Contents
1 Definitions of terms
1.1 802.16d
1.2 802.16e
1.3 Fixed WiMAX
1.4 Mobile WiMAX
2 Uses
2.1 Broadband access
2.1.1 Subscriber units
2.2 Mobile applications
3 Technical information
3.1 MAC layer/data link layer
3.2 Physical layer
3.3 Comparison with Wi-Fi
3.4 Spectrum allocation issues
3.4.1 Limitations
3.5 Silicon implementations
4 Standards
4.1 IEEE 802.16e-2005
4.2 WiBro
5 Associations
5.1 WiMAX Forum
5.2 WiMAX Spectrum Owners Alliance - WiSOA
6 Competing technologies
6.1 3G and 4G cellular phone Systems
6.1.1 Mobile Broadband Wireless Access
6.2 Internet-oriented systems
6.3 Comparison
7 Future development
8 Current deployments
Definitions of terms[1]
The terms "fixed WiMAX", "mobile WiMAX", "802.16d" and "802.16e" are frequently used incorrectly. Correct definitions are:
[edit] 802.16d
Strictly speaking, 802.16d has never existed as a standard. The standard is correctly called 802.16-2004. However, since this standard is frequently called 802.16d, that usage also takes place in this article to assist readability.
[edit] 802.16e
Just as 802.16d has never existed, a standard called 802.16e hasn't either. It's an amendment to 802.16-2004, so is not a standard in its own right. It's properly referred to as 802.16e-2005.
[edit] Fixed WiMAX
This is a phrase frequently used to refer to systems built using 802.16-2004 ('802.16d') as the air interface technology.
[edit] Mobile WiMAX
A phrase frequently used to refer to systems built using 802.16e-2005 as the air interface technology. "Mobile WiMAX" implementations are therefore frequently used to deliver pure fixed services.
[edit] Uses
The bandwidth and reach of WiMAX make it suitable for the following potential applications:
Connecting Wi-Fi hotspots with each other and to other parts of the Internet.
Providing a wireless alternative to cable and DSL for last mile (last km) broadband access.
Providing high-speed data and telecommunications services.
Providing a diverse source of Internet connectivity as part of a business continuity plan. That is, if a business has a fixed and a wireless Internet connection, especially from unrelated providers, they are unlikely to be affected by the same service outage.
Providing nomadic connectivity.
[edit] Broadband access
Many companies are closely examining WiMAX for "last mile" connectivity at high data rates. The resulting competition may bring lower pricing for both home and business customers, or bring broadband access to places where it has been economically unavailable. Prior to WiMAX, many operators have been using proprietary fixed wireless technologies for broadband services.
WiMAX access was used to assist with communications in Aceh, Indonesia, after the tsunami in December 2004. All communication infrastructures, other than HAM Radio in the area were destroyed making the survivors unable to communicate with people outside the disaster area and vice versa. WiMAX provided broadband access that helped regenerate communication to and from Aceh.
[edit] Subscriber units
WiMAX subscriber units are available in both indoor and outdoor versions from several manufacturers. Self-install indoor units are convenient, but radio losses mean that the subscriber must be significantly closer to the WiMAX base station than with professionally installed external units. As such, indoor installed units require a much higher infrastructure investment as well as operational cost (site lease, backhaul, maintenance) due to the high number of base stations required to cover a given area. Indoor units are comparable in size to a cable modem or DSL modem. Outdoor units are roughly the size of a laptop PC, and their installation is comparable to a residential satellite dish.
With the advent of mobility ("16e"), there is an increasing focus on portable units. This includes handsets (similar to cellular smartphones) and PC peripherals (PC Cards or USB dongles). In addition, there is much emphasis from operators on consumer electronics devices (games terminals, MP3 players and the like); it is notable this is more similar to WiFi than 3G cellular technologies.
[edit] Mobile applications
Some cellular companies are evaluating WiMAX as a means of increasing bandwidth for a variety of data-intensive applications; Sprint Nextel announced in mid-2006 that it would invest about US$ 3 billion in a WiMAX technology buildout over the next few years[2].
In line with these possible applications is the technology's ability to serve as a high bandwidth "backhaul" for Internet or cellular phone traffic from remote areas back to an Internet backbone. Although the cost per user/point of WiMAX in a remote application will be higher, it is not limited to such applications, and may be an answer to reducing the cost of T1/E1 backhaul as well. Given the limited wired infrastructure in some developing countries, the costs to install a WiMAX station in conjunction with an existing cellular tower or even as a solitary hub are likely to be small in comparison to developing a wired solution. Areas of low population density and flat terrain are particularly suited to WiMAX and its range. For countries that have skipped wired infrastructure as a result of prohibitive costs and unsympathetic geography, WiMAX can enhance wireless infrastructure in an inexpensive, decentralized, deployment-friendly and effective manner.
[edit] Technical information
WiMAX is a term coined to describe standard, interoperable implementations of IEEE 802.16 wireless networks, in a rather similar way to Wi-Fi being interoperable implementations of the IEEE 802.11 Wireless LAN standard. However, WiMAX is very different from Wi-Fi in the way it works.
[edit] MAC layer/data link layer
In Wi-Fi the media access controller (MAC) uses contention access — all subscriber stations that wish to pass data through a wireless access point (AP) are competing for the AP's attention on a random interrupt basis. This can cause subscriber stations distant from the AP to be repeatedly interrupted by closer stations, greatly reducing their throughput. This makes services such as Voice over IP (VoIP) or IPTV, which depend on an essentially constant Quality of Service (QoS) depending on data rate and interruptibility, difficult to maintain for more than a few simultaneous users.
In contrast, the 802.16 MAC uses a scheduling algorithm for which the subscriber station need compete once (for initial entry into the network). After that it is allocated an access slot by the base station. The time slot can enlarge and contract, but remains assigned to the subscriber station which means that other subscribers cannot use it. In addition to being stable under overload and over-subscription (unlike 802.11), the 802.16 scheduling algorithm can also be more bandwidth efficient. The scheduling algorithm also allows the base station to control QoS parameters by balancing the time-slot assignments among the application needs of the subscriber stations.
[edit] Physical layer
The original WiMAX standard (IEEE 802.16) specified WiMAX for the 10 to 66 GHz range. 802.16a, updated in 2004 to 802.16-2004, added specifications for the 2 to 11 GHz range. 802.16-2004 was updated to 802.16e in 2005 and uses scalable orthogonal frequency-division multiple access (SOFDMA) as opposed to the OFDM version with 256 sub-carriers (of which 200 are used) in 802.16d. More advanced versions including 802.16e also bring Multiple Antenna Support through Multiple-input multiple-output communications (MIMO). This brings potential benefits in terms of coverage, self installation, power consumption, frequency re-use and bandwidth efficiency. 802.16e also adds a capability for full mobility support. The WiMAX certification allows vendors with 802.16d products to sell their equipment as WiMAX certified, thus ensuring a level of interoperability with other certified products, as long as they fit the same profile.
Most commercial interest is in the 802.16d and .16e standards, since the lower frequencies used in these variants suffer less from inherent signal attenuation and therefore give improved range and in-building penetration. Already today, a number of networks throughout the World are in commercial operation using certified WiMAX equipment compliant with the 802.16d standard.
[edit] Comparison with Wi-Fi
Possibly due to the fact both WiMAX and Wi-Fi begin with the same two letters, and are based upon IEEE standards beginning with 802., and both have a connection to wireless connectivity and the Internet, comparisons and confusion between the two are frequent. Despite this, both standards are aimed at different applications.
WiMAX is a long range system, covering many kilometers, that uses licensed or unlicensed spectrum to deliver a point-to-point connection to the Internet from an ISP to an end user. Different 802.16 standards provide different types of access, from mobile (analogous to access via a cellphone) to fixed (an alternative to wired access, where the end user's wireless termination point is fixed in location.)
Wi-Fi is a shorter range system, typically hundreds of meters, that uses unlicensed spectrum to provide access to a network, typically covering only the network operator's own property. Typically Wi-Fi is used by an end user to access their own network, which may or may not be connected to the Internet. If WiMAX provides services analogous to a cellphone, Wi-Fi is more analogous to a cordless phone.
WiMAX is highly scalable from what are called 'femto' scale remote stations to multi-sector 'maxi' scale base that handle complex tasks of management and mobile handoff functions and include MIMO-AAS smart antenna subsystems.
Due to the ease and low cost with which Wi-Fi can be deployed, it is sometimes used to provide Internet access to third parties within a single room or building available to the provider, sometimes informally, and sometimes as part of a business relationship. For example, many coffee shops, hotels, and transportation hubs contain Wi-Fi access points providing access to the Internet for patrons.
[edit] Spectrum allocation issues
The 802.16 specification applies across a wide swath of the RF spectrum. However, specification is not the same as permission to use. There is no uniform global licensed spectrum for WiMAX. In the US, the biggest segment available is around 2.5 GHz[3], and is already assigned, primarily to Sprint Nextel and Clearwire. Elsewhere in the world, the most likely bands used will be around 3.5 GHz, 2.3/2.5 GHz, or 5 GHz, with 2.3/2.5 GHz probably being most important in Asia. Some countries in Asia like India, Vietnam and Indonesia will use 3.3 GHz.
Analogue TV bands may become available for WiMAX use, but await the complete rollout of digital TV, and there will be other uses suggested for that spectrum. In the U.S. The FCC auction for this spectrum is scheduled for the end of 2007. EU commissioner Viviane Reding has suggested re-allocation of 500-800 Mhz spectrum for wireless communication, including WiMAX [1].
It seems likely that there will be several variants of 802.16, depending on local regulatory conditions and thus on which spectrum is used, even if everything but the underlying radio frequencies is the same. WiMAX equipment will not, therefore, be as portable as it might have been - perhaps even less so than WiFi, whose assigned channels in unlicensed spectrum vary little from jurisdiction to jurisdiction. Manufacturers are compelled to provide multi-spectrum devices that can be used across different regions and regulatory requirements. WISOA is an organization that promotes roaming among service providers. However, this is no different than current mobile phones with dual band, triband and even quadband capabilities. Equipment vendors have already announced the development of multiband subscriber units.
WiMAX profiles define channel size, TDD/FDD and other necessary attributes in order to have inter-operating products. The current fixed profiles define for both TDD and FDD profiles. At this point, all of the mobile profiles are TDD only. The fixed profiles have channel sizes of 3.5 MHz, 5 MHz, 7 MHz and 10 MHz. The mobile profiles are 5 MHz, 8.75 MHz and 10 MHz. (Note: the 802.16 standard allows far wider variety of channels, but only the above subsets are supported as WiMAX profiles).
A major trend in capabilities that mitigates concerns about homogeneous global spectrum is the increasing ability of multi-mode and multi-spectrum wireless ICs and antenna components. This provides a form of De facto deregulation of spectrum as multiple spectra can be aggregated via hardware. This trend has appeared in the cellular and now will advance in the field based on the WiMAX standard for wireless broadband. Keep in mind that this is the 1st broad standard for WWAN systems under which standard multi-mode silicon is being developed.
One of the significant advantages of advanced wireless systems such as WiMAX is spectral efficiency. For example, 802.16-2004 (fixed) has a spectral efficiency of 3.7 bit/s/hertz. But all 3.5-4G wireless systems similarly offer spectral efficiencies that are within a few tenths of a percent. The more notable advantage comes from combining SOFDMA with smart antenna technologies. This multiplies the effective spectral efficiency through multiple reuse and smart network deployment topologies. The direct use of frequency domain organization simplifies designs using MIMO-AAS compared to CDMA/WCDMA methods, resulting in more effective systems.
[edit] Limitations
A commonly held misconception is that WiMAX will deliver 70 Mbit/s, over 30 miles (48 kilometers). Both of these qualities are true individually, given ideal circumstances, but they are not simultaneously true. WiMAX has some similarities to DSL in this respect, where one can either have high bandwidth or long reach, but not both simultaneously.
The nature of wireless communications dictates that the antenna design will have a substantial impact on what is achievable. Typically, Fixed WiMAX networks have a higher-gain directional antenna installed externally at the customer's premises which results in greatly increased range and throughput. Mobile WiMAX networks comprise mostly of indoor CPEs such as desktop modems, laptops with integrated Mobile WiMAX or other Mobile WiMAX devices. Mobile WiMAX devices typically have an antenna design which is of lower-gain by nature due to their inherent omni-directional (and portable) design. In practice this means that in a line-of-sight environment with a portable Mobile WiMAX CPE, symmetrical speeds of 10 Mbit/s at 10 km could be delivered, but in urban environments it is more likely that these devices will not have line-of-sight and therefore users may only receive 10 Mbit/s over 2 km. Higher-gain directional antennas can be used with a Mobile WiMAX network with range and throughput benefits but the obvious loss of practical mobility.
Like most wireless systems, available bandwidth is shared between users in a given radio sector, so performance could deteriorate in the case of many active users on a single sector, especially if proper capacity planning has not been undertaken. In practice, many users will have a range of 2-, 4-, 6-, 8-, 10- or 12 Mbit/s services and additional radio cards will be added to the base station to increase the capacity as required.
Because of this, various granular and distributed network architectures are being incorporated into WiMAX through independent development and within the 802.16j, mobile multi-hop relay (MMR) task group. This includes wireless mesh, grids, network remote station repeaters which can extend networks and connect to back-haul.
[edit] Silicon implementations
A critical requirement for the success of a new technology is the availability of low-cost chipsets and silicon implementations.
Intel is a leader in promoting WiMAX, and has developed its own chipset. However, it is notable that most of the major semiconductor companies have to date been more cautious of involvement and most of the solutions come from specialist smaller or start-up suppliers. For client-side these include Altair, Beceem, GCI, Runcom and a number of others. Both Sequans and Wavesat manufacture solutions for both clients and network while Picochip is focussed on WiMAX chipsets for basestations.
[edit] Standards
The current WiMAX incarnation, Mobile WiMAX, is based upon IEEE Std 802.16e-2005[4], approved in December 2005. It is an amendment of IEEE Std 802.16-2004[5] and so the actual standard is 802.16-2004 as amended by 802.16e-2005 - the specifications need to be read together to understand them.
IEEE Std 802.16-2004 addresses only fixed systems. It replaced IEEE Standards 802.16-2001, 802.16c-2002, and 802.16a-2003.
[edit] IEEE 802.16e-2005
IEEE 802.16e-2005 improves upon IEEE 802.16-2004 by:
Scaling of the Fast Fourier Transform (FFT) to the channel bandwidth in order to keep the carrier spacing constant across different channel bandwidths (1.25-20 MHz). Constant carrier spacing results in a higher spectrum efficiency in wide channels, and a cost reduction in narrow channels. Also known as Scalable OFDMA (SOFDMA).
Improving NLOS coverage by utilizing advanced antenna diversity schemes, and hybrid-Automatic Retransmission Request (hARQ)
Improving capacity and coverage by introducing Adaptive Antenna Systems (AAS) and Multiple Input Multiple Output (MIMO) technology
Increasing system gain by use of denser sub-channelization, thereby improving indoor penetration
Introducing high-performance coding techniques such as Turbo Coding and Low-Density Parity Check (LDPC), enhancing security and NLOS performance
Introducing downlink sub-channelization, allowing administrators to trade coverage for capacity or vice versa
Enhanced Fast Fourier Transform algorithm can tolerate larger delay spreads, increasing resistance to multipath interference
Adding an extra QoS class (enhanced real-time Polling Service) more appropriate for VoIP applications.
Adding support for mobility (soft and hard handover between base stations). This is seen as one of the most important aspects of 802.16e-2005, and is the very basis of 'Mobile WiMAX'.
802.16d vendors point out that fixed WiMAX offers the benefit of available commercial products and implementations optimized for fixed access. It is a popular standard among alternative service providers and operators in developing areas due to its low cost of deployment and advanced performance in a fixed environment. Fixed WiMAX is also seen as a potential standard for backhaul of wireless base stations such as cellular, WiFi or even Mobile WiMAX.
SOFDMA (used in 802.16e-2005) and OFDM256 (802.16d) are not compatible so most equipment will have to be replaced if an operator wants or needs to move to the later standard. However, some manufacturers are planning to provide a migration path for older equipment to SOFDMA compatibility which would ease the transition for those networks which have already made the OFDM256 investment. This affects a relatively small number users and operators.
[edit] WiBro
South Korea's electronics and telecommunication industry spearheaded by Samsung Electronics and ETRI has developed its own standard, WiBro. In late 2004, Intel and LG Electronics have agreed on a merger of mobile WiBro(S-OFDMA modulation) and fixed WiMAX(OFDM modulation) to produce a new standard dubbed Mobile WiMax(802.16e-2005) combining features from both to avoid a future standard war. From this point on WiBro became a specific subset implementation of 802.16e-2005 standard over 8.75 Mhz channels in 2.3 Ghz band, whereas Mobile WiMax represents a full implementation of 802.16e-2005 standard that supports flexible channel size and service band. The side effect of this merger is that Mobile WiMax gears are backward compatible with WiBro gears but not with fixed WiMax gears, reflecting its WiBro originated heritage.
WiBro has South Korean government support with the requirement for each carrier to spend over US$1 billion for deployments. Korea sought to develop WiBro as a regional and potentially international alternative to 3.5G or 4G cellular systems. But given the lack of momentum as a standard, WiBro has joined WiMAX and agreed to harmonize with the similar OFDMA 802.16e version of the standard.
What makes WiBro roll-outs a good "test case" for the overall WiMAX effort is that it is mobile, well thought out for delivery of wireless broadband services, and the fact that the deployment is taking place in a highly sophisticated, broadband-saturated market. WiBro will go up against 3G and very high bandwidth wire-line services rather than as gap-filler or rural under-served market deployments often thought of as "best fit" markets for WiMAX.
As such, WiBRO is now best described as a particular profile within WiMAX with 8.75MHz channel in the 2.3GHz band.
[edit] Associations
[edit] WiMAX Forum
The WiMAX Forum is the organization dedicated to certifying the interoperability of WiMAX products. Those that pass conformance and interoperability testing achieve the "WiMAX Forum Certified" designation and can display this mark on their products and marketing materials. Some vendors claim that their equipment is "WiMAX-ready", "WiMAX-compliant", or "pre-WiMAX", if they are not officially WiMAX Forum Certified. [6]
[edit] WiMAX Spectrum Owners Alliance - WiSOA
WiSOA is the first global organization composed exclusively of owners of WiMAX spectrum without plans to deploy WiMAX technology in those bands. WiSOA is focussed on the regulation, commercialisation, and deployment of WiMAX spectrum in the 2.3–2.5 GHz and the 3.4–3.5 GHz ranges. WiSOA are dedicated to educating and informing its members, industry representatives and government regulators of the importance of WiMAX spectrum, its use, and the potential for WiMAX to revolutionise broadband.[7]
[edit] Competing technologies
Within the marketplace, WiMAX's main competition comes from existing widely deployed wireless systems such as UMTS and CDMA2000, as well as a number of Internet oriented systems such as HIPERMAN and WiBro.
[edit] 3G and 4G cellular phone Systems
Both of the two major 3G systems, CDMA2000 and UMTS, compete with WiMAX. Both aim to offer DSL-class Internet access in addition to phone service. UMTS has also been enhanced to compete directly with WiMAX in the form of UMTS-TDD, which can use WiMAX oriented spectrum and provides a more consistent, if lower bandwidth at peak, user experience than WiMAX.
3G cellular phone systems usually benefit from already having entrenched infrastructure, being upgraded from earlier systems. Users can usually fall back to older systems when they move out of range of upgraded equipment, often relatively seamlessly.
The major cellular standards are being evolved to so-called 4G, high bandwidth, low latency, all-IP networks with voice services built on top. With GSM/UMTS, the move to 4G is the 3GPP Long Term Evolution effort. For AMPS/TIA derived standards such as CDMA2000, a replacement called Ultra Mobile Broadband is under development. In both cases, existing air interfaces are being discarded, in favour of OFDMA for the downlink and a variety of OFDM based solutions for the uplink, much akin to WiMAX.
In some areas of the world the wide availability of UMTS and a general desire for standardization has meant spectrum has not been allocated for WiMAX: in July 2005, the EU-wide frequency allocation for WiMAX was blocked.
[edit] Mobile Broadband Wireless Access
Mobile Broadband Wireless Access (MBWA) is a technology being developed by IEEE 802.20 and is aimed at wireless mobile broadband for operations from 120 to 350 km/h. The 802.20 standard has taken on many of the methods behind Mobile WiMAX, including high speed dynamic modulation and similar scalable OFDMA capabilities. It apparently retains fast hand-off, Forward Error Correction (FEC) and cell edge enhancements.
The Working Group was temporarily suspended in mid 2006 by the IEE-SA Standards Board since it had been the subject of a number of appeals, and a preliminary investigation of one of these "revealed a lack of transparency, possible 'dominance,' and other irregularities in the Working Group" [8].
In September 2006 the IEE-SA Standards Board approved a plan to enable the working group to continue under new conditions, and the standard is now expected to be finalized by Q2 2008.
[edit] Internet-oriented systems
Early WirelessMAN standards, the European standard HIPERMAN and Korean standard WiBro have been harmonized as part of WiMAX and are no longer seen as competition but as complementary. All networks now being deployed in South Korea, the home of the Wibro standard, are now WiMAX.
As a short-range mobile Internet solution, such as in cafes and at transportation hubs like airports, the popular WiFi 802.11b/g system is widely deployed, and provides enough coverage for some users to feel subscription to a WiMAX service is unnecessary.
The following table should be treated with caution as it only shows peak rates which are potentially very misleading.
[edit] Comparison
Main article: Comparison of wireless data standards
v • d • e
Comparison of Mobile Internet Access methods
Standard
Family
Primary Use
Radio Tech
Downlink (Mbps)
Uplink (Mbps)
Notes
802.16e
WiMAX
Mobile Internet
MIMO-SOFDMA
70
70
Quoted speeds only achievable at very short ranges, more practically 10 Mbps at 10 km.
HIPERMAN
HIPERMAN
Mobile Internet
OFDM
56.9
56.9
WiBro
WiBro
Mobile Internet
OFDMA
50
50
Mobile range (900 m)
iBurst
iBurst 802.20
Mobile Internet
HC-SDMA
64
64
3-12 km
UMTS W-CDMAHSDPA+HSUPA
UMTS/3GSM
Mobile phone
CDMA/FDD
.38414.4
.3845.76
HSDPA widely deployed. Typical downlink rates today 1-2Mbps, ~200kbps uplink; future downlink up to 28.8Mbps.
UMTS-TDD
UMTS/3GSM
Mobile Internet
CDMA/TDD
16
16
Reported speeds according to IPWireless using 16QAM modulation similar to HSDPA+HSUPA
LTE UMTS
UMTS/4GSM
General 4G
OFDMA/MIMO/SC-FDMA (HSOPA)
>100
>50
Still in development
1xRTT
CDMA2000
Mobile phone
CDMA
0.144
0.144
Obsoleted by EV-DO
EV-DO 1x Rev. 0EV-DO 1x Rev.AEV-DO Rev.B
CDMA2000
Mobile Internet
CDMA/FDD
2.453.14.9xN
0.151.81.8xN
Rev B note: N is the number of 1.25 MHz chunks of spectrum used. Not yet deployed.
Notes: All speeds are theoretical maximums and will vary by a number of factors, including the use of external antennae, distance from the tower and the ground speed (i.e. communications on a train may be poorer than when standing still.) Usually the bandwidth is shared between several terminals. The performance of each technology is determined by a number of constraints, including the spectral efficiency of the technology, the cell sizes used, and the amount of spectrum available. For more information, see Comparison of wireless data standards.
Future development
Mobile WiMAX based upon 802.16e-2005 has been accepted as IP-OFDMA for inclusion as the sixth wireless link system under IMT-2000. This can hasten acceptance by regulatory authorities and operators for use in cellular spectrum. WiMAX II, 802.16m will be proposed for IMT-Advanced 4G.
The goal for the long term evolution of both WiMAX and LTE is to achieve 100 Mbit/s mobile and 1 Gbit/s fixed-nomadic bandwidth as set by ITU for 4G NGMN (Next Generation Mobile Network) systems through the adaptive use of MIMO-AAS and smart, granular network topologies. 3GPP LTE and WiMAX-m are concentrating much effort on MIMO-AAS, mobile multi-hop relay networking and related developments needed to deliver 10X and higher Co-Channel reuse multiples.
Since the evolution of core air-link technologies has approached the practical limits imposed by Shannon's Theorem, the evolution of wireless has embarked on pursuit of the 3X to 10X+ greater bandwidth and network efficiency gains that are expected by advances in the spatial and smart wireless broadband networking technologies. What will clearly define 4G more than either WCDMA or OFDMA wireless link methods will be wireless networks that more effectively adapt to and take advantage of available spectrum.
Current deployments
Main article: List of Deployed WiMAX networks(Country by Country List)
The WiMAX Forum now lists over 350 WiMAX trials and deployments. Current and planned deployments and the bands in which they operate and the standards they use are listed in the above article.
Tuesday, August 14, 2007
Monday, August 13, 2007
Wi-Fi
Wi-Fi is a wireless technology brand owned by the Wi-Fi Alliance intended to improve the interoperability of wireless local area network products based on the IEEE 802.11 standards.
Common applications for Wi-Fi include Interne and VoIP phone access, gaming, and network connectivity for consumer electronics such as televisions, DVD players, and digital cameras.
Contents[hide]
1 Definition
2 Uses
3 Advantages of Wi-Fi
4 Disadvantages of Wi-Fi
5 Standard Devices
6 Non-Standard Devices
6.1 Embedded systems
7 Unintended and intended use by outsiders
8 Wi-Fi vs. amateur radio
9 Media reports of health risks
10 History
11 Origin and meaning of the term "Wi-Fi"
//
[edit] Definition
Main article: Wi-Fi Technical Information
According to the brand style guide of the Wi-Fi Alliance (the owner of the Wi-Fi brand):
"Products which successfully pass the Wi-Fi Alliance testing may use the Wi-Fi CERTIFIED brand. The Alliance tests and certifies the interoperability of wireless LAN products based on the IEEE 802.11 standards. Studies show that 88% of consumers prefer products which have been tested by an independent organization."
Wi-Fi technologies have gone through several generations since their inception in 1997. Wi-Fi is supported to different extents under Microsoft Windows, Apple Mac OS and open source Unix and Linux operating systems. Contrary to popular belief, Wi-Fi is not an abbreviation for "Wireless Fidelity" (see "Origin and meaning of the term "Wi-Fi"" below).
[edit] Uses
A Wi-Fi enabled device such as a PC, cell phone or PDA can connect to the Internet when within range of a wireless network connected to the Internet. The area covered by one or several interconnected access points is called a hotspot. Hotspots can cover as little as a single room with wireless-opaque walls or as much as many square miles covered by overlapping access points. Wi-Fi can also be used to create a mesh network. Both architectures are used in community networks.[citation needed]
Wi-Fi also allows connectivity in peer-to-peer (wireless ad-hoc network) mode, which enables devices to connect directly with each other. This connectivity mode is useful in consumer electronics and gaming applications.
When the technology was first commercialized there were many problems because consumers could not be sure that products from different vendors would work together. The Wi-Fi Alliance began as a community to solve this issue so as to address the needs of the end user and allow the technology to mature. The Alliance created the branding Wi-Fi CERTIFIED to show consumers that products are interoperable with other products displaying the same branding.
Many consumer devices use Wi-Fi. Amongst others, personal computers can network to each other and connect to the Internet, mobile computers can connect to the Internet from any Wi-Fi hotspot, and digital cameras can transfer images wirelessly.
Routers which incorporate a DSL or cable modem and a Wi-Fi access point are often used in homes and other premises, and provide Internet access and internetworking to all devices connected wirelessly or by cable into them. Devices supporting Wi-Fi can also be connected in ad-hoc mode for client-to-client connections without a router.
Business and industrial Wi-Fi is widespread as of 2007. In business environments, increasing the number of Wi-Fi access points provides redundancy, support for fast roaming and increased overall network capacity by using more channels or creating smaller cells. Wi-Fi enables wireless voice applications (VoWLAN or WVOIP). Over the years, Wi-Fi implementations have moved toward 'thin' access points, with more of the network intelligence housed in a centralized network appliance, relegating individual Access Points to be simply 'dumb' radios. Outdoor applications may utilize true mesh topologies. As of 2007 Wi-Fi installations can provide a secure computer networking gateway, firewall, DHCP server, intrusion detection system, and other functions.
In addition to restricted use in homes and offices, Wi-Fi is publicly available at Wi-Fi hotspots provided either free of charge or to subscribers to various providers. Free hotspots are often provided by businesses such as hotels, restaurants, and airports who offer the service to attract or assist clients. Sometimes free Wi-Fi is provided by enthusiasts, or by organisations or authorities who wish to promote business in their area. Metropolitan-wide WiFi (Mu-Fi) already has more than 300 projects in process.[1]
[edit] Advantages of Wi-Fi
Wi-Fi allows LANs to be deployed without cabling for client devices, typically reducing the costs of network deployment and expansion. Spaces where cables cannot be run, such as outdoor areas and historical buildings, can host wireless LANs.
As of 2007 wireless network adapters are built into most modern laptops. The price of chipsets for Wi-Fi continues to drop, making it an economical networking option included in ever more devices. Wi-Fi has become widespread in corporate infrastructures, which also helps with the deployment of RFID technology that can piggyback on Wi-Fi [2].
Different competitive brands of access points and client network interfaces are inter-operable at a basic level of service. Products designated as "Wi-Fi Certified" by the Wi-Fi Alliance are backwards inter-operable. Wi-Fi is a global set of standards. Unlike mobile telephones, any standard Wi-Fi device will work anywhere in the world.
Wi-Fi is widely available in more than 250,000 public hotspots and tens of millions of homes and corporate and university campuses worldwide. WPA is not easily cracked if strong passwords are used and WPA2 encryption has no known weaknesses. New protocols for Quality of Service (WMM) make Wi-Fi more suitable for latency-sensitive applications (such as voice and video), and power saving mechanisms (WMM Power Save) improve battery operation.
[edit] Disadvantages of Wi-Fi
Spectrum assignments and operational limitations are not consistent worldwide. Most of Europe allows for an additional 2 channels beyond those permitted in the US (1-13 vs 1-11); Japan has one more on top of that (1-14), and some countries, like Spain, prohibit use of the lower-numbered channels. Europe, as of 2007, is now essentially homogeneous in this respect. Some countries, such as Italy, formerly required a 'general authorization' for any Wi-Fi used outside an operator's own premises, or require something akin to an operator registration.[citation needed] Equivalent isotropically radiated power (EIRP) in the EU is limited to 20 dBm (0.1 W).
Power consumption is fairly high compared to some other low-bandwidth standards, such as Zigbee and Bluetooth, making battery life a concern.
The most common wireless encryption standard, Wired Equivalent Privacy or WEP, has been shown to be easily breakable even when correctly configured. Wi-Fi Protected Access (WPA and WPA2), which began shipping in 2003, aims to solve this problem and is now available on most products. Wi-Fi Access Points typically default to an open (encryption-free) mode. Novice users benefit from a zero-configuration device that works out of the box, but without security enabled, providing open wireless access to their LAN. To turn security on requires the user to configure the device, usually via a software graphical user interface (GUI). Wi-Fi networks that are open (unencrypted) can be monitored and used to read and copy data (including personal information) transmitted over the network, unless another security method is used to secure the data, such as a VPN or a secure web page. (HTTPS/Secure Socket Layer)
Many 2.4 GHz 802.11b and 802.11g Access points default to the same channel on initial startup, contributing to congestion on certain channels. To change the channel of operation for an access point requires the user to configure the device.
Wi-Fi networks have limited range. A typical Wi-Fi home router using 802.11b or 802.11g with a stock antenna might have a range of 45 m (150 ft) indoors and 90 m (300 ft) outdoors. Range also varies with frequency band. Wi-Fi in the 2.4 GHz frequency block has slightly better range than Wi-Fi in the 5 GHz frequency block. Outdoor range with improved (directional) antennas can be several kilometres or more with line-of-sight.
Wi-Fi pollution, or an excessive number of access points in the area, especially on the same or neighboring channel, can prevent access and interfere with the use of other access points by others, caused by overlapping channels in the 802.11g/b spectrum, as well as with decreased signal-to-noise ratio (SNR) between access points. This can be a problem in high-density areas, such as large apartment complexes or office buildings with many Wi-Fi access points. Additionally, other devices use the 2.4 GHz band: microwave ovens, cordless phones, baby monitors, security cameras, and Bluetooth devices can cause significant additional interference.
It is also an issue when municipalities[3], or other large entities such as universities, seek to provide large area coverage. Everyone is considered equal for the base standard without 802.11e/WMM when they use the band. This openness is also important to the success and widespread use of 2.4 GHz Wi-Fi, but makes it unsuitable for "must-have" public service functions or where reliability is required.
Interoperability issues between brands or proprietary deviations from the standard can disrupt connections or lower throughput speeds on other user's devices that are within range. Additionally, Wi-Fi devices do not, as of 2007, pick channels to avoid interference.[citation needed]
[edit] Standard Devices
Wireless access points connects a group of wireless devices to an adjacent wired LAN. An access point is similar to an ethernet hub, relaying data between connected wireless devices in addition to a (usually) single connected wired device, most often an ethernet hub or switch, allowing wireless devices to communicate with other wired devices.
Wireless adapters allow devices to connect to a wireless network. These adapters connect to devices using various external or internal interconnects such as PCI, miniPCI, USB, ExpressCard, Cardbus and PC card. Most newer laptop computers are equipped with internal adapters. Internal cards are generally more difficult to install.
Wireless routers integrate WAP, ethernet switch, and internal Router firmware application that provides IP Routing, NAT, and DNS forwarding through an integrated WAN interface. A wireless router allows wired and wireless ethernet LAN devices to connect to a (usually) single WAN device such as cable modem or DSL modem. A wireless router allows all three devices (mainly the access point and router) to be configured through one central utility. This utility is most usually an integrated web server which serves web pages to wired and wireless LAN clients and often optionally to WAN clients. This utility may also be an application that is run on a desktop computer such as Apple's AirPort.
Wireless Ethernet bridges connect a wired network to a wireless network. This is different from an access point in the sense that an access point connects wireless devices to a wired network at the data-link layer. Two wireless bridges may be used to connect two wired networks over a wireless link, useful in situations where a wired connection may be unavailable, such as between two separate homes.
Wireless range extenders or wireless repeaters can extend the range of an existing wireless network. Range extenders can be strategically placed to elongate a signal area or allow for the signal area to reach around barriers such as those created in L-shaped corridors. Wireless devices connected through repeaters will suffer from an increased latency for each hop. Additionally, a wireless device at the end of chain of wireless repeaters will have a throughput that is limited by the weakest link within the repeater chain.
Most commercial devices (routers, access points, bridges, repeaters) designed for home or business environments use either RP-SMA or RP-TNC antenna connectors. PCI wireless adapters also mainly use RP-SMA connectors. Most PC card and USB wireless only have internal antennas etched on their printed circuit board while some have MMCX connector or MC-Card external connections in addition to an internal antenna. A few USB cards have a RP-SMA connector. Most Mini PCI wireless cards utilize Hirose U.FL connectors, but cards found in various wireless appliances contain all of the connectors listed. Many high-gain (and homebuilt antennas) utilize the Type N connector more commonly used by other radio communications methods.
[edit] Non-Standard Devices
USB-Wi-Fi adapters, food container "Cantennas", parabolic reflectors, and many other types of self-built antennae are increasingly made by do-it-yourselfers. For minimal budgets, as low as a few dollars, signal strength and range can be improved dramatically.
As of 2007, Long Range Wi-Fi kits have begun to enter the market. Companies like BroadbandXpress offer long range, inexpensive kits that can be setup with limited knowledge. These kits utilize specialized antennas which increase the range of Wi-Fi dramatically, up to the world record 137.2 miles (220 km). These kits are commonly used to get broadband internet to a place without direct broadband access.[4]
The longest link ever achieved was by the Swedish space agency. They attained 310 km, but used 6 watt amplifiers to reach an overhead stratospheric balloon. [citation needed] The longest link without amplification was 279 km in Venezuela, 2006. [5]
Embedded systems
Wi-Fi availability in the home is on the increase. This extension of the Internet into the home space will increasingly be used for remote monitoring. Examples of remote monitoring include security systems and tele-medicine. In all these kinds of implementation, if the Wi-Fi provision is provided using a system running one of operating systems mentioned above, then it becomes unfeasible due to weight, power consumption and cost issues.
Increasingly in the last few years (particularly as of early 2007), embedded Wi-Fi modules have become available which come with a real-time operating system and provide a simple means of wireless enabling any device which has and communicates via a serial port.
This allows simple monitoring devices -- for example, a portable ECG monitor hooked up to a patient in their home -- to be created. This Wi-Fi enabled device effectively becomes part of the internet cloud and can communicate with any other node on the internet. The data collected can hop via the home's Wi-Fi access point to anywhere on the internet.
These Wi-Fi modules are designed so that minimal Wi-Fi knowledge is required by designers to wireless enable their product.
[edit] Unintended and intended use by outsiders
Wikinews has related news:
Florida man charged with stealing WiFi
Measures to deter unauthorized users include suppressing the AP's service set identifier (SSID) broadcast, allowing only computers with known MAC addresses to join the network, and various encryption standards. Access points and computers using no encryption are vulnerable to eavesdropping by an attacker armed with packet sniffer software. If the eavesdropper has the ability to change his MAC address then he can potentially join the network by spoofing an authorised address.
WEP encryption can protect against casual snooping but may also produce a misguided sense of security since freely available tools such as AirSnort can quickly recover WEP encryption keys. Once it has seen 5-10 million encrypted packets, AirSnort will determine the encryption password in under a second.[6] The newer Wi-Fi Protected Access (WPA) and IEEE 802.11i (WPA2) encyption standards do not have the serious weaknesses of WEP encryption, but require strong passphrases for full security.
Recreational exploration of other people's access points has become known as wardriving, and the leaving of graffiti describing available services as warchalking. These activities may be illegal in certain jurisdictions, but existing legislation and case-law is often unclear.
However, it is also common for people to unintentionally use others' Wi-Fi networks without explicit authorization. Operating systems such as Windows XP SP2 and Mac OS X automatically connect to an available wireless network, depending on the network configuration. A user who happens to start up a laptop in the vicinity of an access point may find the computer has joined the network without any visible indication. Moreover, a user intending to join one network may instead end up on another one if the latter's signal is stronger. In combination with automatic discovery of other network resources (see DHCP and Zeroconf) this could possibly lead wireless users to send sensitive data to the wrong destination. [citation needed]
In Singapore, using another person's Wi-Fi network is illegal under the Computer Misuse Act. A 17 year old has been arrested for simply tapping into his neighbor's wireless Internet connection and faces up to 3 years' imprisonment and a fine.[7]
[edit] Wi-Fi vs. amateur radio
In the US, Canada and Australia, a portion of the 2.4 GHz Wi-Fi radio spectrum is also allocated to amateur radio users. In the US, FCC Part 15 rules govern non-licensed operators (i.e. most Wi-Fi equipment users). Under Part 15 rules, non-licensed users must "accept" (i.e. endure) interference from licensed users and not cause harmful interference to licensed users. Amateur radio operators are licensed users, and retain what the FCC terms "primary status" on the band, under a distinct set of rules (Part 97). Under Part 97, licensed amateur operators may construct their own equipment, use very high-gain antennas, and boost output power to 100 watts on frequencies covered by Wi-Fi channels 2-6. However, Part 97 rules mandate using only the minimum power necessary for communications, forbid obscuring the data, and require station identification every 10 minutes. Therefore, output power control is required to meet regulations, and the transmission of any encrypted data (for example https) is questionable.
In practice, microwave power amplifiers are expensive. On the other hand, the short wavelength at 2.4 GHz allows for simple construction of very high gain directional antennas. Although Part 15 rules forbid any modification of commercially constructed systems, amateur radio operators may modify commercial systems for optimized construction of long links, for example. Using only 200 mW link radios and high gain directional antennas, a very narrow beam may be used to construct reliable links with minimal radio frequency interference to other users.
[edit] Media reports of health risks
The UK's Health Protection Agency considers there is no consistent evidence of harm from the low power transmissions of Wi-Fi equipment, nevertheless their chairman, Sir William Stewart, stated that it is a sensible precaution to keep the situation under review.[8] Two media items (the latest in an episode of the current affairs television program Panorama in May 2007) reported that schools and families have been removing their Wi-Fi systems as a result.[9] Individual anecdotes of deleterious effects which ceased upon removal of the systems have also been reported including headaches and lethargy.[9]. Consensus amongst scientists is that there is no evidence of harm, and the continuing calls for more research into the effects on human health remain limited. Thirty-seven studies have already been conducted that do not show a causal relationship.[9][10]
[edit] History
Wi-Fi uses both single carrier direct-sequence spread spectrum radio technology (part of the larger family of spread spectrum systems) and multi-carrier OFDM (Orthogonal Frequency Division Multiplexing) radio technology. These regulations then enabled the development of Wi-Fi, its onetime competitor HomeRF, and Bluetooth.
Unlicensed spread spectrum was first made available by the Federal Communications Commission in 1985 and these FCC regulations were later copied with some changes in many other countries enabling use of this technology in all major countries.[11] The FCC action was proposed by Michael Marcus of the FCC staff in 1980 and the subsequent controversial regulatory action took 5 more years. It was part of a broader proposal to allow civil use of spread spectrum technology and was opposed at the time by main stream equipment manufacturers and many radio system operators.
The precursor to Wi-Fi was invented in 1991 by NCR Corporation/AT&T (later Lucent & Agere Systems) in Nieuwegein, the Netherlands. It was initially intended for cashier systems; the first wireless products were brought on the market under the name WaveLAN with speeds of 1 Mbit/s to 2 Mbit/s. Vic Hayes, who held the chair of IEEE 802.11 for 10 years and has been named the 'father of Wi-Fi,' was involved in designing standards such as IEEE 802.11b, 802.11a and 802.11g.
[edit] Origin and meaning of the term "Wi-Fi"
Despite the similarity between the terms "Wi-Fi" and "Hi-Fi", statements reportedly made by Phil Belanger of the Wi-Fi Alliance contradict the popular conclusion that "Wi-Fi" stands for "Wireless Fidelity".[12] According to Mr Belanger, the Interbrand Corporation developed the brand "Wi-Fi" for the Wi-Fi Alliance to use to describe WLAN products that are based on the IEEE 802.11 standards. In Mr Belanger's words, "Wi-Fi and the yin yang style logo were invented by Interbrand. We [the founding members of the Wireless Ethernet Compatibility Alliance, now called the Wi-Fi Alliance] hired Interbrand to come up with the name and logo that we could use for our interoperability seal and marketing efforts. We needed something that was a little catchier than 'IEEE 802.11b Direct Sequence'."
थे wi-फि अलायंस themselves इन्वोकेद थे टर्म "वायरलेस फिदेलिटी" विथ थे मार्केटिंग ऑफ़ अ टैग लीन, "थे स्टैंडर्ड फ़ॉर वायरलेस फिदेलिटी", बुत लेटर रेमोवेद थे टैग फ्रॉम थेइर मार्केटिंग. थे wi-फि अलायंस नोव सीम्स तो दिस्कौरागे थे प्रोपगेशन ऑफ़ थे नोतिओं ठाट "wi-फि" स्तान्ड्स फ़ॉर "वायरलेस फिदेलिटी", बुत इत हस बीन रेफेर्रेड तो अस सुच ब्य थे wi-फि अलायंस इन व्हिते पपेर्स कर्रेंत्ल्य हेल्ड इन थेइर क्नोव्लेद्गे बसें: "... अ प्रोमिसिंग मार्केट फ़ॉर वायरलेस फिदेलिटी (wi-फि) नेत्वोर्क एक़ुइप्मेन्त्." [13] and "A Short History of WLANs... The association created the Wi-Fi (Wireless Fidelity) logo to indicate that a product had been certified for interoperability."
Common applications for Wi-Fi include Interne and VoIP phone access, gaming, and network connectivity for consumer electronics such as televisions, DVD players, and digital cameras.
Contents[hide]
1 Definition
2 Uses
3 Advantages of Wi-Fi
4 Disadvantages of Wi-Fi
5 Standard Devices
6 Non-Standard Devices
6.1 Embedded systems
7 Unintended and intended use by outsiders
8 Wi-Fi vs. amateur radio
9 Media reports of health risks
10 History
11 Origin and meaning of the term "Wi-Fi"
//
[edit] Definition
Main article: Wi-Fi Technical Information
According to the brand style guide of the Wi-Fi Alliance (the owner of the Wi-Fi brand):
"Products which successfully pass the Wi-Fi Alliance testing may use the Wi-Fi CERTIFIED brand. The Alliance tests and certifies the interoperability of wireless LAN products based on the IEEE 802.11 standards. Studies show that 88% of consumers prefer products which have been tested by an independent organization."
Wi-Fi technologies have gone through several generations since their inception in 1997. Wi-Fi is supported to different extents under Microsoft Windows, Apple Mac OS and open source Unix and Linux operating systems. Contrary to popular belief, Wi-Fi is not an abbreviation for "Wireless Fidelity" (see "Origin and meaning of the term "Wi-Fi"" below).
[edit] Uses
A Wi-Fi enabled device such as a PC, cell phone or PDA can connect to the Internet when within range of a wireless network connected to the Internet. The area covered by one or several interconnected access points is called a hotspot. Hotspots can cover as little as a single room with wireless-opaque walls or as much as many square miles covered by overlapping access points. Wi-Fi can also be used to create a mesh network. Both architectures are used in community networks.[citation needed]
Wi-Fi also allows connectivity in peer-to-peer (wireless ad-hoc network) mode, which enables devices to connect directly with each other. This connectivity mode is useful in consumer electronics and gaming applications.
When the technology was first commercialized there were many problems because consumers could not be sure that products from different vendors would work together. The Wi-Fi Alliance began as a community to solve this issue so as to address the needs of the end user and allow the technology to mature. The Alliance created the branding Wi-Fi CERTIFIED to show consumers that products are interoperable with other products displaying the same branding.
Many consumer devices use Wi-Fi. Amongst others, personal computers can network to each other and connect to the Internet, mobile computers can connect to the Internet from any Wi-Fi hotspot, and digital cameras can transfer images wirelessly.
Routers which incorporate a DSL or cable modem and a Wi-Fi access point are often used in homes and other premises, and provide Internet access and internetworking to all devices connected wirelessly or by cable into them. Devices supporting Wi-Fi can also be connected in ad-hoc mode for client-to-client connections without a router.
Business and industrial Wi-Fi is widespread as of 2007. In business environments, increasing the number of Wi-Fi access points provides redundancy, support for fast roaming and increased overall network capacity by using more channels or creating smaller cells. Wi-Fi enables wireless voice applications (VoWLAN or WVOIP). Over the years, Wi-Fi implementations have moved toward 'thin' access points, with more of the network intelligence housed in a centralized network appliance, relegating individual Access Points to be simply 'dumb' radios. Outdoor applications may utilize true mesh topologies. As of 2007 Wi-Fi installations can provide a secure computer networking gateway, firewall, DHCP server, intrusion detection system, and other functions.
In addition to restricted use in homes and offices, Wi-Fi is publicly available at Wi-Fi hotspots provided either free of charge or to subscribers to various providers. Free hotspots are often provided by businesses such as hotels, restaurants, and airports who offer the service to attract or assist clients. Sometimes free Wi-Fi is provided by enthusiasts, or by organisations or authorities who wish to promote business in their area. Metropolitan-wide WiFi (Mu-Fi) already has more than 300 projects in process.[1]
[edit] Advantages of Wi-Fi
Wi-Fi allows LANs to be deployed without cabling for client devices, typically reducing the costs of network deployment and expansion. Spaces where cables cannot be run, such as outdoor areas and historical buildings, can host wireless LANs.
As of 2007 wireless network adapters are built into most modern laptops. The price of chipsets for Wi-Fi continues to drop, making it an economical networking option included in ever more devices. Wi-Fi has become widespread in corporate infrastructures, which also helps with the deployment of RFID technology that can piggyback on Wi-Fi [2].
Different competitive brands of access points and client network interfaces are inter-operable at a basic level of service. Products designated as "Wi-Fi Certified" by the Wi-Fi Alliance are backwards inter-operable. Wi-Fi is a global set of standards. Unlike mobile telephones, any standard Wi-Fi device will work anywhere in the world.
Wi-Fi is widely available in more than 250,000 public hotspots and tens of millions of homes and corporate and university campuses worldwide. WPA is not easily cracked if strong passwords are used and WPA2 encryption has no known weaknesses. New protocols for Quality of Service (WMM) make Wi-Fi more suitable for latency-sensitive applications (such as voice and video), and power saving mechanisms (WMM Power Save) improve battery operation.
[edit] Disadvantages of Wi-Fi
Spectrum assignments and operational limitations are not consistent worldwide. Most of Europe allows for an additional 2 channels beyond those permitted in the US (1-13 vs 1-11); Japan has one more on top of that (1-14), and some countries, like Spain, prohibit use of the lower-numbered channels. Europe, as of 2007, is now essentially homogeneous in this respect. Some countries, such as Italy, formerly required a 'general authorization' for any Wi-Fi used outside an operator's own premises, or require something akin to an operator registration.[citation needed] Equivalent isotropically radiated power (EIRP) in the EU is limited to 20 dBm (0.1 W).
Power consumption is fairly high compared to some other low-bandwidth standards, such as Zigbee and Bluetooth, making battery life a concern.
The most common wireless encryption standard, Wired Equivalent Privacy or WEP, has been shown to be easily breakable even when correctly configured. Wi-Fi Protected Access (WPA and WPA2), which began shipping in 2003, aims to solve this problem and is now available on most products. Wi-Fi Access Points typically default to an open (encryption-free) mode. Novice users benefit from a zero-configuration device that works out of the box, but without security enabled, providing open wireless access to their LAN. To turn security on requires the user to configure the device, usually via a software graphical user interface (GUI). Wi-Fi networks that are open (unencrypted) can be monitored and used to read and copy data (including personal information) transmitted over the network, unless another security method is used to secure the data, such as a VPN or a secure web page. (HTTPS/Secure Socket Layer)
Many 2.4 GHz 802.11b and 802.11g Access points default to the same channel on initial startup, contributing to congestion on certain channels. To change the channel of operation for an access point requires the user to configure the device.
Wi-Fi networks have limited range. A typical Wi-Fi home router using 802.11b or 802.11g with a stock antenna might have a range of 45 m (150 ft) indoors and 90 m (300 ft) outdoors. Range also varies with frequency band. Wi-Fi in the 2.4 GHz frequency block has slightly better range than Wi-Fi in the 5 GHz frequency block. Outdoor range with improved (directional) antennas can be several kilometres or more with line-of-sight.
Wi-Fi pollution, or an excessive number of access points in the area, especially on the same or neighboring channel, can prevent access and interfere with the use of other access points by others, caused by overlapping channels in the 802.11g/b spectrum, as well as with decreased signal-to-noise ratio (SNR) between access points. This can be a problem in high-density areas, such as large apartment complexes or office buildings with many Wi-Fi access points. Additionally, other devices use the 2.4 GHz band: microwave ovens, cordless phones, baby monitors, security cameras, and Bluetooth devices can cause significant additional interference.
It is also an issue when municipalities[3], or other large entities such as universities, seek to provide large area coverage. Everyone is considered equal for the base standard without 802.11e/WMM when they use the band. This openness is also important to the success and widespread use of 2.4 GHz Wi-Fi, but makes it unsuitable for "must-have" public service functions or where reliability is required.
Interoperability issues between brands or proprietary deviations from the standard can disrupt connections or lower throughput speeds on other user's devices that are within range. Additionally, Wi-Fi devices do not, as of 2007, pick channels to avoid interference.[citation needed]
[edit] Standard Devices
Wireless access points connects a group of wireless devices to an adjacent wired LAN. An access point is similar to an ethernet hub, relaying data between connected wireless devices in addition to a (usually) single connected wired device, most often an ethernet hub or switch, allowing wireless devices to communicate with other wired devices.
Wireless adapters allow devices to connect to a wireless network. These adapters connect to devices using various external or internal interconnects such as PCI, miniPCI, USB, ExpressCard, Cardbus and PC card. Most newer laptop computers are equipped with internal adapters. Internal cards are generally more difficult to install.
Wireless routers integrate WAP, ethernet switch, and internal Router firmware application that provides IP Routing, NAT, and DNS forwarding through an integrated WAN interface. A wireless router allows wired and wireless ethernet LAN devices to connect to a (usually) single WAN device such as cable modem or DSL modem. A wireless router allows all three devices (mainly the access point and router) to be configured through one central utility. This utility is most usually an integrated web server which serves web pages to wired and wireless LAN clients and often optionally to WAN clients. This utility may also be an application that is run on a desktop computer such as Apple's AirPort.
Wireless Ethernet bridges connect a wired network to a wireless network. This is different from an access point in the sense that an access point connects wireless devices to a wired network at the data-link layer. Two wireless bridges may be used to connect two wired networks over a wireless link, useful in situations where a wired connection may be unavailable, such as between two separate homes.
Wireless range extenders or wireless repeaters can extend the range of an existing wireless network. Range extenders can be strategically placed to elongate a signal area or allow for the signal area to reach around barriers such as those created in L-shaped corridors. Wireless devices connected through repeaters will suffer from an increased latency for each hop. Additionally, a wireless device at the end of chain of wireless repeaters will have a throughput that is limited by the weakest link within the repeater chain.
Most commercial devices (routers, access points, bridges, repeaters) designed for home or business environments use either RP-SMA or RP-TNC antenna connectors. PCI wireless adapters also mainly use RP-SMA connectors. Most PC card and USB wireless only have internal antennas etched on their printed circuit board while some have MMCX connector or MC-Card external connections in addition to an internal antenna. A few USB cards have a RP-SMA connector. Most Mini PCI wireless cards utilize Hirose U.FL connectors, but cards found in various wireless appliances contain all of the connectors listed. Many high-gain (and homebuilt antennas) utilize the Type N connector more commonly used by other radio communications methods.
[edit] Non-Standard Devices
USB-Wi-Fi adapters, food container "Cantennas", parabolic reflectors, and many other types of self-built antennae are increasingly made by do-it-yourselfers. For minimal budgets, as low as a few dollars, signal strength and range can be improved dramatically.
As of 2007, Long Range Wi-Fi kits have begun to enter the market. Companies like BroadbandXpress offer long range, inexpensive kits that can be setup with limited knowledge. These kits utilize specialized antennas which increase the range of Wi-Fi dramatically, up to the world record 137.2 miles (220 km). These kits are commonly used to get broadband internet to a place without direct broadband access.[4]
The longest link ever achieved was by the Swedish space agency. They attained 310 km, but used 6 watt amplifiers to reach an overhead stratospheric balloon. [citation needed] The longest link without amplification was 279 km in Venezuela, 2006. [5]
Embedded systems
Wi-Fi availability in the home is on the increase. This extension of the Internet into the home space will increasingly be used for remote monitoring. Examples of remote monitoring include security systems and tele-medicine. In all these kinds of implementation, if the Wi-Fi provision is provided using a system running one of operating systems mentioned above, then it becomes unfeasible due to weight, power consumption and cost issues.
Increasingly in the last few years (particularly as of early 2007), embedded Wi-Fi modules have become available which come with a real-time operating system and provide a simple means of wireless enabling any device which has and communicates via a serial port.
This allows simple monitoring devices -- for example, a portable ECG monitor hooked up to a patient in their home -- to be created. This Wi-Fi enabled device effectively becomes part of the internet cloud and can communicate with any other node on the internet. The data collected can hop via the home's Wi-Fi access point to anywhere on the internet.
These Wi-Fi modules are designed so that minimal Wi-Fi knowledge is required by designers to wireless enable their product.
[edit] Unintended and intended use by outsiders
Wikinews has related news:
Florida man charged with stealing WiFi
Measures to deter unauthorized users include suppressing the AP's service set identifier (SSID) broadcast, allowing only computers with known MAC addresses to join the network, and various encryption standards. Access points and computers using no encryption are vulnerable to eavesdropping by an attacker armed with packet sniffer software. If the eavesdropper has the ability to change his MAC address then he can potentially join the network by spoofing an authorised address.
WEP encryption can protect against casual snooping but may also produce a misguided sense of security since freely available tools such as AirSnort can quickly recover WEP encryption keys. Once it has seen 5-10 million encrypted packets, AirSnort will determine the encryption password in under a second.[6] The newer Wi-Fi Protected Access (WPA) and IEEE 802.11i (WPA2) encyption standards do not have the serious weaknesses of WEP encryption, but require strong passphrases for full security.
Recreational exploration of other people's access points has become known as wardriving, and the leaving of graffiti describing available services as warchalking. These activities may be illegal in certain jurisdictions, but existing legislation and case-law is often unclear.
However, it is also common for people to unintentionally use others' Wi-Fi networks without explicit authorization. Operating systems such as Windows XP SP2 and Mac OS X automatically connect to an available wireless network, depending on the network configuration. A user who happens to start up a laptop in the vicinity of an access point may find the computer has joined the network without any visible indication. Moreover, a user intending to join one network may instead end up on another one if the latter's signal is stronger. In combination with automatic discovery of other network resources (see DHCP and Zeroconf) this could possibly lead wireless users to send sensitive data to the wrong destination. [citation needed]
In Singapore, using another person's Wi-Fi network is illegal under the Computer Misuse Act. A 17 year old has been arrested for simply tapping into his neighbor's wireless Internet connection and faces up to 3 years' imprisonment and a fine.[7]
[edit] Wi-Fi vs. amateur radio
In the US, Canada and Australia, a portion of the 2.4 GHz Wi-Fi radio spectrum is also allocated to amateur radio users. In the US, FCC Part 15 rules govern non-licensed operators (i.e. most Wi-Fi equipment users). Under Part 15 rules, non-licensed users must "accept" (i.e. endure) interference from licensed users and not cause harmful interference to licensed users. Amateur radio operators are licensed users, and retain what the FCC terms "primary status" on the band, under a distinct set of rules (Part 97). Under Part 97, licensed amateur operators may construct their own equipment, use very high-gain antennas, and boost output power to 100 watts on frequencies covered by Wi-Fi channels 2-6. However, Part 97 rules mandate using only the minimum power necessary for communications, forbid obscuring the data, and require station identification every 10 minutes. Therefore, output power control is required to meet regulations, and the transmission of any encrypted data (for example https) is questionable.
In practice, microwave power amplifiers are expensive. On the other hand, the short wavelength at 2.4 GHz allows for simple construction of very high gain directional antennas. Although Part 15 rules forbid any modification of commercially constructed systems, amateur radio operators may modify commercial systems for optimized construction of long links, for example. Using only 200 mW link radios and high gain directional antennas, a very narrow beam may be used to construct reliable links with minimal radio frequency interference to other users.
[edit] Media reports of health risks
The UK's Health Protection Agency considers there is no consistent evidence of harm from the low power transmissions of Wi-Fi equipment, nevertheless their chairman, Sir William Stewart, stated that it is a sensible precaution to keep the situation under review.[8] Two media items (the latest in an episode of the current affairs television program Panorama in May 2007) reported that schools and families have been removing their Wi-Fi systems as a result.[9] Individual anecdotes of deleterious effects which ceased upon removal of the systems have also been reported including headaches and lethargy.[9]. Consensus amongst scientists is that there is no evidence of harm, and the continuing calls for more research into the effects on human health remain limited. Thirty-seven studies have already been conducted that do not show a causal relationship.[9][10]
[edit] History
Wi-Fi uses both single carrier direct-sequence spread spectrum radio technology (part of the larger family of spread spectrum systems) and multi-carrier OFDM (Orthogonal Frequency Division Multiplexing) radio technology. These regulations then enabled the development of Wi-Fi, its onetime competitor HomeRF, and Bluetooth.
Unlicensed spread spectrum was first made available by the Federal Communications Commission in 1985 and these FCC regulations were later copied with some changes in many other countries enabling use of this technology in all major countries.[11] The FCC action was proposed by Michael Marcus of the FCC staff in 1980 and the subsequent controversial regulatory action took 5 more years. It was part of a broader proposal to allow civil use of spread spectrum technology and was opposed at the time by main stream equipment manufacturers and many radio system operators.
The precursor to Wi-Fi was invented in 1991 by NCR Corporation/AT&T (later Lucent & Agere Systems) in Nieuwegein, the Netherlands. It was initially intended for cashier systems; the first wireless products were brought on the market under the name WaveLAN with speeds of 1 Mbit/s to 2 Mbit/s. Vic Hayes, who held the chair of IEEE 802.11 for 10 years and has been named the 'father of Wi-Fi,' was involved in designing standards such as IEEE 802.11b, 802.11a and 802.11g.
[edit] Origin and meaning of the term "Wi-Fi"
Despite the similarity between the terms "Wi-Fi" and "Hi-Fi", statements reportedly made by Phil Belanger of the Wi-Fi Alliance contradict the popular conclusion that "Wi-Fi" stands for "Wireless Fidelity".[12] According to Mr Belanger, the Interbrand Corporation developed the brand "Wi-Fi" for the Wi-Fi Alliance to use to describe WLAN products that are based on the IEEE 802.11 standards. In Mr Belanger's words, "Wi-Fi and the yin yang style logo were invented by Interbrand. We [the founding members of the Wireless Ethernet Compatibility Alliance, now called the Wi-Fi Alliance] hired Interbrand to come up with the name and logo that we could use for our interoperability seal and marketing efforts. We needed something that was a little catchier than 'IEEE 802.11b Direct Sequence'."
थे wi-फि अलायंस themselves इन्वोकेद थे टर्म "वायरलेस फिदेलिटी" विथ थे मार्केटिंग ऑफ़ अ टैग लीन, "थे स्टैंडर्ड फ़ॉर वायरलेस फिदेलिटी", बुत लेटर रेमोवेद थे टैग फ्रॉम थेइर मार्केटिंग. थे wi-फि अलायंस नोव सीम्स तो दिस्कौरागे थे प्रोपगेशन ऑफ़ थे नोतिओं ठाट "wi-फि" स्तान्ड्स फ़ॉर "वायरलेस फिदेलिटी", बुत इत हस बीन रेफेर्रेड तो अस सुच ब्य थे wi-फि अलायंस इन व्हिते पपेर्स कर्रेंत्ल्य हेल्ड इन थेइर क्नोव्लेद्गे बसें: "... अ प्रोमिसिंग मार्केट फ़ॉर वायरलेस फिदेलिटी (wi-फि) नेत्वोर्क एक़ुइप्मेन्त्." [13] and "A Short History of WLANs... The association created the Wi-Fi (Wireless Fidelity) logo to indicate that a product had been certified for interoperability."
Thursday, August 9, 2007
Mahindra & Mahindra Limited
TypePublic
Founded1945
Headquarters
people
Keshub Mahindra (Chairman), Anand G.Mahindra (Vice-Chairman & Managing Director)
Industry
Automotive and Tractor
Products
utility vehiclescommercial vehiclestractor
Revenue
$4.5 Bn (2007)
Employees
11,600
Website
http://www.mahindra.com/
HISTORY
Mahindra & Mahindra Limited (M&M) is a major automaker in India. It is the flagship company of the Mahindra Group. The company was set up in 1945 as Mahindra & Mohammed.[3] It traded steel with suppliers in England and the United States. M&M began by assembling complete knock down(CKD) Jeeps in 1949. It expanded to indigenous manufacture of Jeep vehicles with a high level of local content under license from Kaiser Jeep and later American Motors (AMC).
M&M soon branched out into manufacturing agricultural tractorsand light commercial vehicles (LCVs). It later expanded its operations to secure a significant presence in many more important sectors. The company has now transformed itself into a group that caters to the Indian and overseas markets with a presence in vehicles, farm equipment, information technology, trade and finance related services, as well as infrastructure development.
By 2005, M&M had become the largest producer of SUVs in India. The company has recently started a separate sector, the Mahindra Systems and Automotive Technologies (MSAT), to focus on developing components and offering engineering services
M&M soon branched out into manufacturing agricultural tractorsand light commercial vehicles (LCVs). It later expanded its operations to secure a significant presence in many more important sectors. The company has now transformed itself into a group that caters to the Indian and overseas markets with a presence in vehicles, farm equipment, information technology, trade and finance related services, as well as infrastructure development.
By 2005, M&M had become the largest producer of SUVs in India. The company has recently started a separate sector, the Mahindra Systems and Automotive Technologies (MSAT), to focus on developing components and offering engineering services
Overview 
The Mahindra Group is a US $4.5 billion* conglomerate and has a leadership position in the Indian automotive sector. Mahindra & Mahindra Ltd. is the flagship company of the Group. M&M comprises of the Automotive Sector, the Farm Equipment Sector and the Systems & Technologies Sector. It is a leading manufacturer of multi-utility vehicles and tractors. Mahindra & Mahindra completed 60 years of business excellence in 2005. Set up in 1945 to make general-purpose utility vehicles for the Indian market, M&M first became known as the maker of the iconic Jeep in India. Mahindra & Mahindra rapidly grew from being a maker of army vehicles to a major automobile and tractor manufacturer with a growing global appetite. M&M initiated a process of product enhancement and globalization. It made strategic acquisitions of plants in China and the United Kingdom, and has three assembly plants in the USA. M&M has partnerships with international companies like Renault SA, France, Nissan and International Truck and Engine Corporation, USA. M&M made its entry into the passenger car segment with Logan in April 2007 under the Mahindra Renault JV. M&M will make its maiden entry into the heavy trucks segment with Mahindra International, the joint venture with International Truck, USA. M&M’s Automotive Sector makes a wide rage of vehicles including MUVs, LCVs and three wheelers. M&M is the largest manufacturer of MUVs, offering over 20 models including new generation multi-utility vehicles like the Scorpio and the Bolero. The company is a market leader in the Utility Vehicle segment. M&M's products are being exported to the USA, Russia and several other countries in Africa, Asia, Europe and Latin America. Its global subsidiaries include Mahindra Europe Srl. based in Italy, Mahindra USA Inc., Mahindra South Africa and Mahindra (China) Tractor Co. Ltd. Mahindra Farm Equipment Sector has come to be recognised as a powerful symbol of productivity and performance. M&M is the fourth largest tractor company in the world. It is also the largest manufacturer of tractors in India with sustained market leadership of around 24 years. It designs, develops, manufactures and markets tractors as well as farm implements. The Sector has also found significant success in the international market. Mahindra (China) Tractor Co. Ltd. manufactures tractors for the growing Chinese market and is a hub for tractor exports to the USA and other western nations. M&M has a 100% subsidiary, Mahindra USA, where it assembles products for the American market. FES received the coveted Deming Application Prize for manufacturing in 2003, for establishing Total Quality Management in all operations. M&M Ltd. is the only tractor company in the world to have achieved this honor. Formed in 2004, by M&M, Systech Sector is a response to the increasingly competitive automotive components industry. Providing an extensive range of services from design to delivery, Systech intends to create the worlds most valuable and innovative auto components business by partnering with global customers to satisfy their business needs. Towards this goal, M&M has acquired three international companies in the forging space -- Stokes Forgings in the UK, Jeco Holding AG and Schöneweiss GmbH in Germany. Through these acquisitions and by finding value wherever it may be, Mahindra has created the fifth largest forging company in the world and one that it feels will become the best as well. Over the years, M&M has transformed itself into a company that has a leadership position in all the sectors it operates in and has a growing global footprint.
The Mahindra Group is a US $4.5 billion* conglomerate and has a leadership position in the Indian automotive sector. Mahindra & Mahindra Ltd. is the flagship company of the Group. M&M comprises of the Automotive Sector, the Farm Equipment Sector and the Systems & Technologies Sector. It is a leading manufacturer of multi-utility vehicles and tractors. Mahindra & Mahindra completed 60 years of business excellence in 2005. Set up in 1945 to make general-purpose utility vehicles for the Indian market, M&M first became known as the maker of the iconic Jeep in India. Mahindra & Mahindra rapidly grew from being a maker of army vehicles to a major automobile and tractor manufacturer with a growing global appetite. M&M initiated a process of product enhancement and globalization. It made strategic acquisitions of plants in China and the United Kingdom, and has three assembly plants in the USA. M&M has partnerships with international companies like Renault SA, France, Nissan and International Truck and Engine Corporation, USA. M&M made its entry into the passenger car segment with Logan in April 2007 under the Mahindra Renault JV. M&M will make its maiden entry into the heavy trucks segment with Mahindra International, the joint venture with International Truck, USA. M&M’s Automotive Sector makes a wide rage of vehicles including MUVs, LCVs and three wheelers. M&M is the largest manufacturer of MUVs, offering over 20 models including new generation multi-utility vehicles like the Scorpio and the Bolero. The company is a market leader in the Utility Vehicle segment. M&M's products are being exported to the USA, Russia and several other countries in Africa, Asia, Europe and Latin America. Its global subsidiaries include Mahindra Europe Srl. based in Italy, Mahindra USA Inc., Mahindra South Africa and Mahindra (China) Tractor Co. Ltd. Mahindra Farm Equipment Sector has come to be recognised as a powerful symbol of productivity and performance. M&M is the fourth largest tractor company in the world. It is also the largest manufacturer of tractors in India with sustained market leadership of around 24 years. It designs, develops, manufactures and markets tractors as well as farm implements. The Sector has also found significant success in the international market. Mahindra (China) Tractor Co. Ltd. manufactures tractors for the growing Chinese market and is a hub for tractor exports to the USA and other western nations. M&M has a 100% subsidiary, Mahindra USA, where it assembles products for the American market. FES received the coveted Deming Application Prize for manufacturing in 2003, for establishing Total Quality Management in all operations. M&M Ltd. is the only tractor company in the world to have achieved this honor. Formed in 2004, by M&M, Systech Sector is a response to the increasingly competitive automotive components industry. Providing an extensive range of services from design to delivery, Systech intends to create the worlds most valuable and innovative auto components business by partnering with global customers to satisfy their business needs. Towards this goal, M&M has acquired three international companies in the forging space -- Stokes Forgings in the UK, Jeco Holding AG and Schöneweiss GmbH in Germany. Through these acquisitions and by finding value wherever it may be, Mahindra has created the fifth largest forging company in the world and one that it feels will become the best as well. Over the years, M&M has transformed itself into a company that has a leadership position in all the sectors it operates in and has a growing global footprint.
Models
Mahindra Bolero
Mahindra Bolero Camper
Mahindra Scorpio
Mahindra-Renault Logan (in cooperation with Renault
Mahindra Bolero
Mahindra Bolero Camper
Mahindra Scorpio
Mahindra-Renault Logan (in cooperation with Renault
Saturday, August 4, 2007
HISTORYThe story of one of India's favourite brands reads almost like a fairy tale. Once upon a time, in 1892 to be precise, a biscuit company was started in a nondescript house in Calcutta (now Kolkata) with an initial investment of Rs. 295. The company we all know as Britannia today.
The beginnings might have been humble-the dreams were anything but. By 1910, with the advent of electricity, Britannia mechanised its operations, and in 1921, it became the first company east of the Suez Canal to use imported gas ovens. Britannia's business was flourishing. But, more importantly, Britannia was acquiring a reputation for quality and value. As a result, during the tragic World War II, the Government reposed its trust in Britannia by contracting it to supply large quantities of "service biscuits" to the armed forces.
As time moved on, the biscuit market continued to grow… and Britannia grew along with it. In 1975, the Britannia Biscuit Company took over the distribution of biscuits from Parry's who till now distributed Britannia biscuits in India. In the subsequent public issue of 1978, Indian shareholding crossed 60%, firmly establishing the Indianness of the firm. The following year, Britannia Biscuit Company was re-christened Britannia Industries Limited (BIL). Four years later in 1983, it crossed the Rs. 100 crores revenue mark.
On the operations front, the company was making equally dynamic strides. In 1992, it celebrated its Platinum Jubilee. In 1997, the company unveiled its new corporate identity - "Eat Healthy, Think Better" - and made its first foray into the dairy products market. In 1999, the "Britannia Khao, World Cup Jao" promotion further fortified the affinity consumers had with 'Brand Britannia'.
Britannia strode into the 21st Century as one of India's biggest brands and the pre-eminent food brand of the country. It was equally recognised for its innovative approach to products and marketing: the Lagaan Match was voted India's most successful promotional activity of the year 2001 while the delicious Britannia 50-50 Maska-Chaska became India's most successful product launch. In 2002, Britannia's New Business Division formed a joint venture with Fonterra, the world's second largest Dairy Company, and Britannia New Zealand Foods Pvt. Ltd. was born. In recognition of its vision and accelerating graph, Forbes Global rated Britannia 'One amongst the Top 200 Small Companies of the World', and The Economic Times pegged Britannia India's 2nd Most Trusted Brand.
Today, more than a century after those tentative first steps, Britannia's fairy tale is not only going strong but blazing new standards, and that miniscule initial investment has grown by leaps and bounds to crores of rupees in wealth for Britannia's shareholders. The company's offerings are spread across the spectrum with products ranging from the healthy and economical Tiger biscuits to the more lifestyle-oriented Milkman Cheese. Having succeeded in garnering the trust of almost one-third of India's one billion population and a strong management at the helm means Britannia will continue to dream big on its path of innovation and quality. And millions of consumers will savour the results, happily ever after.
MILESTONE
1892
The Genesis - Britannia established with an investment of Rs. 295 in Kolkata
Advent of electricity sees operations mechanised
1921
Imported machinery introduced; Britannia becomes the first company East of the Suez to use gas ovens
1939 - 44
Sales rise exponentially to Rs.16,27,202 in 1939 Becomes bulk supplier of 'Service Biscuits' to the armed forces during World War II -->
During 1944 sales ramp up by more than eight times to reach Rs.1.36 crore
1975
Britannia Biscuit Company takes over biscuit distribution from Parry's
1978
Public issue - Indian shareholding crosses 60%
1979
Re-christened Britannia Industries Ltd. (BIL)
1983
Sales cross Rs.100 crore
1989
The Executive Office relocated to Bangalore
1992
BIL celebrates its Platinum Jubilee
1993
Wadia Group acquires stake in ABIL, UK and becomes an equal partner with Groupe Danone in BIL
1994
Volumes cross 1,00,000 tons of biscuits
1997
Re-birth - new corporate identity 'Eat Healthy, Think Better' leads to new mission: 'Make every third Indian a Britannia consumer'
BIL enters the dairy products market
1999
"Britannia Khao World Cup Jao" - a major success! Profit up by 37% 2000
Forbes Global Ranking - Britannia among Top 300 small companies
2001
BIL ranked one of India's biggest brands
No.1 food brand of the country
Britannia Lagaan Match: India's most successful promotional activity of the year
Maska Chaska: India's most successful FMCG launch
2002
BIL launches joint venture with Fonterra, the world's second largest dairy company
Britannia New Zealand Foods Pvt. Ltd. is born
Rated as 'One amongst the Top 200 Small Companies of the World' by Forbes Global
Economic Times ranks BIL India's 2nd Most Trusted Brand
Pure Magic -Winner of the Worldstar, Asiastar and Indiastar award for packaging
2003
'Treat Duet'- most successful launch of the year
Britannia Khao World Cup Jao rocks the consumer lives yet again
2004
Britannia accorded the status of being a 'Superbrand'
Volumes cross 3,00,000 tons of biscuits
Good Day adds a new variant - Choconut - in its range
2005
GLoble partners
The Wadia Group of India along with Groupe Danone of France, are equal shareholders in ABIL, UK which is a major shareholder in Britannia Industries Limited. GROUPE DANONE is an International FMCG Major specializing in Fresh Dairy Products, Bottled Water and Biscuits/Cereals. One of the World leaders in the food industry, these are some of the laurels it possesses:
No # 1 worldwide in Fresh Dairy Products
No # 1 worldwide equally placed in Bottled Water (by volume)
No # 2 worldwide in Biscuits and Cereal Products Through its three core businesses (Fresh Dairy Products, Beverages and Biscuits and Cereal Products), GROUPE DANONE is committed to improving the lives of people around the world by providing them with better food products, a wider variety of flavors and healthier pleasures. Its dominant position worldwide is based on major international brands and on its solid presence in local markets (about 70% of global sales come from brands that are local market leaders). GROUPE DANONE is recognized for the dynamism and strength of its brands:
Danone: the leading brand worldwide for Fresh Dairy Products; DANONE represents almost 20% of the international market. DANONE is present in 40 countries worldwide.
Evian: the best selling mineral water brand, with 1.5 billion bottles sold every year. Present in the 5 continents, in 125 countries.
LU: the second brand worldwide, the first biscuits brand of GROUPE DANONE, which represents almost the half of the sales for the Biscuits and Cereal Products division. LU is mainly present in Western Europe.
Wahaha: the leading brand for refreshing still water (water, ready made tea, fruit juices). The brand is one of the most popular in China, with more than 1.5 billion liters of water sold each year. Its name means "the child who laughs". Financial results:
Net sales in 2004: 13,024 million Euros (+6.1% at comparable scope)
Operational Income: 1,706 million Euros
Operating Margin: 13.1% (+40 base points in relation to 2004).
Re-birth of Tiger - 'Swasth Khao, Tiger Ban Jao' becomes the popular chant!
Britannia launched 'Greetings' range of premium assorted gift packs
The new plant in Uttaranchal, commissioned ahead of schedule.
The launch of yet another exciting snacking option - Britannia 50-50 Pepper Chakkar
Annual Performance (FY 2006)
Britannia's gross sales turnover increased to Rs 18,179 mn in 2005-06 from Rs 16,154 mn in the previous year, registering a growth of 13%. Operating profit at Rs 1,763 mn increased by 7%, profit before tax and exceptional items at Rs. 1,958 mn declined by 19% against 2004-05 , impacted by the profit on sale of long term investments that accrued to 'other income' last year.
Friday, August 3, 2007
BSE
SENSEX - THE BAROMETER OF INDIAN CAPITAL MARKETS
Download Index ConstituentsClick to search Historical Notices on Index Replacements
Introduction
For the premier Stock Exchange that pioneered the stock broking activity in India, 128 years of experience seems to be a proud milestone. A lot has changed since 1875 when 318 persons became members of what today is called "The Stock Exchange, Mumbai" by paying a princely amount of Re1.Since then, the country's capital markets have passed through both good and bad periods. The journey in the 20th century has not been an easy one. Till the decade of eighties, there was no scale to measure the ups and downs in the Indian stock market. The Stock Exchange, Mumbai (BSE) in 1986 came out with a stock index that subsequently became the barometer of the Indian stock market.SENSEX is not only scientifically designed but also based on globally accepted construction and review methodology. First compiled in 1986, SENSEX is a basket of 30 constituent stocks representing a sample of large, liquid and representative companies. The base year of SENSEX is 1978-79 and the base value is 100. The index is widely reported in both domestic and international markets through print as well as electronic media.The Index was initially calculated based on the "Full Market Capitalization" methodology but was shifted to the free-float methodology with effect from September 1, 2003. The "Free-float Market Capitalization" methodology of index construction is regarded as an industry best practice globally. All major index providers like MSCI, FTSE, STOXX, S&P and Dow Jones use the Free-float methodology.Due to is wide acceptance amongst the Indian investors; SENSEX is regarded to be the pulse of the Indian stock market. As the oldest index in the country, it provides the time series data over a fairly long period of time (From 1979 onwards). Small wonder, the SENSEX has over the years become one of the most prominent brands in the country.The growth of equity markets in India has been phenomenal in the decade gone by. Right from early nineties the stock market witnessed heightened activity in terms of various bull and bear runs. The SENSEX captured all these events in the most judicial manner. One can identify the booms and busts of the Indian stock market through SENSEX.SENSEX Calculation MethodologySENSEX is calculated using the "Free-float Market Capitalization" methodology. As per this methodology, the level of index at any point of time reflects the Free-float market value of 30 component stocks relative to a base period. The market capitalization of a company is determined by multiplying the price of its stock by the number of shares issued by the company. This market capitalization is further multiplied by the free-float factor to determine the free-float market capitalization.The base period of SENSEX is 1978-79 and the base value is 100 index points. This is often indicated by the notation 1978-79=100. The calculation of SENSEX involves dividing the Free-float market capitalization of 30 companies in the Index by a number called the Index Divisor. The Divisor is the only link to the original base period value of the SENSEX. It keeps the Index comparable over time and is the adjustment point for all Index adjustments arising out of corporate actions, replacement of scrips etc. During market hours, prices of the index scrips, at which latest trades are executed, are used by the trading system to calculate SENSEX every 15 seconds and disseminated in real time.Dollex-30BSE also calculates a dollar-linked version of SENSEX and historical values of this index are available since its inception. (For more details click ‘Dollex series of BSE indices’)Understanding Free-float MethodologyConcept:Free-float Methodology refers to an index construction methodology that takes into consideration only the free-float market capitalization of a company for the purpose of index calculation and assigning weight to stocks in Index. Free-float market capitalization is defined as that proportion of total shares issued by the company that are readily available for trading in the market. It generally excludes promoters' holding, government holding, strategic holding and other locked-in shares that will not come to the market for trading in the normal course. In other words, the market capitalization of each company in a Free-float index is reduced to the extent of its readily available shares in the market.In India, BSE pioneered the concept of Free-float by launching BSE TECk in July 2001 and BANKEX in June 2003. While BSE TECk Index is a TMT benchmark, BANKEX is positioned as a benchmark for the banking sector stocks. SENSEX becomes the third index in India to be based on the globally accepted Free-float Methodology.Major advantages of Free-float Methodology:
A Free-float index reflects the market trends more rationally as it takes into consideration only those shares that are available for trading in the market.
Free-float Methodology makes the index more broad-based by reducing the concentration of top few companies in Index. For example, the concentration of top five companies in SENSEX has fallen under the free-float scenario thereby making the SENSEX more diversified and broad-based.
A Free-float index aids both active and passive investing styles. It aids active managers by enabling them to benchmark their fund returns vis-à-vis an investable index. This enables an apple-to-apple comparison thereby facilitating better evaluation of performance of active managers. Being a perfectly replicable portfolio of stocks, a Free-float adjusted index is best suited for the passive managers as it enables them to track the index with the least tracking error.
Free-float Methodology improves index flexibility in terms of including any stock from the universe of listed stocks. This improves market coverage and sector coverage of the index. For example, under a Full-market capitalization methodology, companies with large market capitalization and low free-float cannot generally be included in the Index because they tend to distort the index by having an undue influence on the index movement. However, under the Free-float Methodology, since only the free-float market capitalization of each company is considered for index calculation, it becomes possible to include such closely held companies in the index while at the same time preventing their undue influence on the index movement.
Globally, the Free-float Methodology of index construction is considered to be an industry best practice and all major index providers like MSCI, FTSE, S&P and STOXX have adopted the same. MSCI, a leading global index provider, shifted all its indices to the Free-float Methodology in 2002. The MSCI India Standard Index, which is followed by Foreign Institutional Investors (FIIs) to track Indian equities, is also based on the Free-float Methodology. NASDAQ-100, the underlying index to the famous Exchange Traded Fund (ETF) - QQQ is based on the Free-float Methodology.Definition of Free-float:
Share holdings held by investors that would not, in the normal course come into the open market for trading are treated as 'Controlling/ Strategic Holdings' and hence not included in free-float. In specific, the following categories of holding are generally excluded from the definition of Free-float:
Holdings by founders/directors/ acquirers which has control element
Holdings by persons/ bodies with "Controlling Interest"
Government holding as promoter/acquirer
Holdings through the FDI Route
Strategic stakes by private corporate bodies/ individuals
Equity held by associate/group companies (cross-holdings)
Equity held by Employee Welfare Trusts
Locked-in shares and shares which would not be sold in the open market in normal course.The remaining shareholders would fall under the Free-float category.Determining Free-float factors of companies:
BSE has designed a Free-float format, which is filled and submitted by all index companies on a quarterly basis with the Exchange. (Format available on www.bseindia.com) The Exchange determines the Free-float factor for each company based on the detailed information submitted by the companies in the prescribed format. Free-float factor is a multiple with which the total market capitalization of a company is adjusted to arrive at the Free-float market capitalization. Once the Free-float of a company is determined, it is rounded-off to the higher multiple of 5 and each company is categorized into one of the 20 bands given below. A Free-float factor of say 0.55 means that only 55% of the market capitalization of the company will be considered for index calculation.Free-float Bands:
% Free-Float
Free-Float Factor
% Free-Float
Free-Float Factor
>0 – 5%
0.05
>50 – 55%
0.55
>5 – 10%
0.10
>55 – 60%
0.60
>10 – 15%
0.15
>60 – 65%
0.65
>15 – 20%
0.20
>65 – 70%
0.70
>20 – 25%
0.25
>70 – 75%
0.75
>25 – 30%
0.30
>75 – 80%
0.80
>30 – 35%
0.35
>80 – 85%
0.85
>35 – 40%
0.40
>85 – 90%
0.90
>40 – 45%
0.45
>90 – 95%
0.95
>45 – 50%
0.50
>95 – 100%
1.00Index Closure Algorithm
The closing SENSEX on any trading day is computed taking the weighted average of all the trades on SENSEX constituents in the last 30 minutes of trading session. If a SENSEX constituent has not traded in the last 30 minutes, the last traded price is taken for computation of the Index closure. If a SENSEX constituent has not traded at all in a day, then its last day's closing price is taken for computation of Index closure. The use of Index Closure Algorithm prevents any intentional manipulation of the closing index value.Maintenance of SENSEXOne of the important aspects of maintaining continuity with the past is to update the base year average. The base year value adjustment ensures that replacement of stocks in Index, additional issue of capital and other corporate announcements like 'rights issue' etc. do not destroy the historical value of the index. The beauty of maintenance lies in the fact that adjustments for corporate actions in the Index should not per se affect the index values.The Index Cell of the exchange does the day-to-day maintenance of the index within the broad index policy framework set by the Index Committee. The Index Cell ensures that SENSEX and all the other BSE indices maintain their benchmark properties by striking a delicate balance between frequent replacements in index and maintaining its historical continuity. The Index Committee of the Exchange comprises of experts on capital markets from all major market segments. They include Academicians, Fund-managers from leading Mutual Funds, Finance-Journalists, Market Participants, Independent Governing Board members, and Exchange administration.On-Line Computation of the Index:During market hours, prices of the index scrips, at which trades are executed, are automatically used by the trading computer to calculate the SENSEX every 15 seconds and continuously updated on all trading workstations connected to the BSE trading computer in real time.Adjustment for Bonus, Rights and Newly issued Capital:The arithmetic calculation involved in calculating SENSEX is simple, but problem arises when one of the component stocks pays a bonus or issues rights shares. If no adjustments were made, a discontinuity would arise between the current value of the index and its previous value despite the non-occurrence of any economic activity of substance. At the Index Cell of the Exchange, the base value is adjusted, which is used to alter market capitalization of the component stocks to arrive at the SENSEX value.The Index Cell of the Exchange keeps a close watch on the events that might affect the index on a regular basis and carries out daily maintenance of all the 14 Indices.
Adjustments for Rights Issues:When a company, included in the compilation of the index, issues right shares, the free-float market capitalisation of that company is increased by the number of additional shares issued based on the theoretical (ex-right) price. An offsetting or proportionate adjustment is then made to the Base Market Capitalisation (see 'Base Market Capitalisation Adjustment' below).
Adjustments for Bonus Issue:When a company, included in the compilation of the index, issues bonus shares, the market capitalisation of that company does not undergo any change. Therefore, there is no change in the Base Market Capitalisation, only the 'number of shares' in the formula is updated.
Other Issues:Base Market Capitalisation Adjustment is required when new shares are issued by way of conversion of debentures, mergers, spin-offs etc. or when equity is reduced by way of buy-back of shares, corporate restructuring etc.
Base Market Capitalisation Adjustment:
The formula for adjusting the Base Market Capitalisation is as follows:
New Market Capitalisation
New Base Market Capitalisation
=
Old Base Market Capitalisation
x
---------------------------------------
Old Market Capitalisation
To illustrate, suppose a company issues right shares which increases the market capitalisation of the shares of that company by say, Rs.100 crores. The existing Base Market Capitalisation (Old Base Market Capitalisation), say, is Rs.2450 crores and the aggregate market capitalisation of all the shares included in the index before the right issue is made is, say Rs.4781 crores. The "New Base Market Capitalisation " will then be:
2450 x (4781+100)
--------------------------
=
Rs.2501.24 crores
4781
This figure of 2501.24 will be used as the Base Market Capitalisation for calculating the index number from then onwards till the next base change becomes necessary.
Back
SENSEX - Scrip selection criteria:
The general guidelines for selection of constituents in SENSEX are as follows:
Listed History:The scrip should have a listing history of at least 3 months at BSE. Exception may be considered if full market capitalisation of a newly listed company ranks among top 10 in the list of BSE universe. In case, a company is listed on account of merger/ demerger/ amalgamation, minimum listing history would not be required.
Trading Frequency:The scrip should have been traded on each and every trading day in the last three months. Exceptions can be made for extreme reasons like scrip suspension etc.
Final Rank:The scrip should figure in the top 100 companies listed by final rank. The final rank is arrived at by assigning 75% weightage to the rank on the basis of three-month average full market capitalisation and 25% weightage to the liquidity rank based on three-month average daily turnover & three-month average impact cost.
Market Capitalization Weightage:The weightage of each scrip in SENSEX based on three-month average free-float market capitalisation should be at least 0.5% of the Index.
Industry Representation:Scrip selection would generally take into account a balanced representation of the listed companies in the universe of BSE.
Track Record:In the opinion of the Committee, the company should have an acceptable track record.Index Review Frequency:The Index Committee meets every quarter to discuss index related issues. In case of a revision in the Index constituents, the announcement of the incoming and outgoing scrips is made six weeks in advance of the actual implementation of the revision of the Index.
Back
History of replacement of scrips in SENSEX
Date
Outgoing Scrips
Replaced by
01.01.1986
Bombay Burmah
Voltas
Asian Cables
Peico
Crompton Greaves
Premier Auto.
Scinda
G.E.Shipping
03.08.1992
Zenith Ltd.
Bharat Forge
19.08.1996
Ballarpur Inds.
Arvind Mills
Bharat Forge
Bajaj Auto
Bombay Dyeing
BHEL
Ceat Tyres
BSES
Century Text.
Colgate
GSFC
Guj. Amb. Cement
Hind. Motors
HPCL
Indian Organic
ICICI
Indian Rayon
IDBI
Kirloskar Cummins
IPCL
Mukand Iron
MTNL
Phlips
Ranbaxy Lab.
Premier Auto
State Bank of India
Siemens
Steel Authority of India
Voltas
Tata Chem
16.11.1998
Arvind Mills
Castrol
G. E. Shipping
Infosys Technologies
IPCL
NIIT Ltd.
Steel Authority of India
Novartis
10.04.2000
I.D.B.I
Dr. Reddy’s Laboratories
Indian Hotels
Reliance Petroleum
Tata Chem
Satyam Computers
Tata Power
Zee Telefilms
08.01.2001
Novartis
Cipla Ltd.
07.01.2002
NIIT Ltd.
HCL Technologies
Mahindra & Mahindra
Hero Honda Motors Ltd.
31.05.2002
ICICI Ltd.
ICICI Bank Ltd.
10.10.2002
Reliance Petroleum Ltd.
HDFC Ltd.
10.11.2003
Castrol India Ltd.
Bharti-Tele-Ventures Ltd.
Colgate Palomive (India) Ltd.
HDFC Bank Ltd.
Glaxo Smithkline Pharma. Ltd.
ONGC Ltd.
HCL Technologies Ltd.
Tata Power Company Ltd.
Nestle (India) Ltd.
Wipro Ltd.
19.05.2004
Larsen & Toubro Ltd.
Maruti Udyog Ltd.
27.09.2004
Mahanagar Telephone Nigam Ltd.
Larsen & Toubro Ltd.
06.06.2005
Hindustan Petroleum Corp Ltd.
National Thermal Power Corpn. Ltd.
Zee Telefilms Ltd.
Tata Consultancy Services Ltd.
12.06.2006
Tata Power Ltd.
Reliance Communiation Ventures Ltd.
09.07.2007
Hero Honda Motors Ltd.
Mahindra & Mahindra Ltd.
Download Index ConstituentsClick to search Historical Notices on Index Replacements
Introduction
For the premier Stock Exchange that pioneered the stock broking activity in India, 128 years of experience seems to be a proud milestone. A lot has changed since 1875 when 318 persons became members of what today is called "The Stock Exchange, Mumbai" by paying a princely amount of Re1.Since then, the country's capital markets have passed through both good and bad periods. The journey in the 20th century has not been an easy one. Till the decade of eighties, there was no scale to measure the ups and downs in the Indian stock market. The Stock Exchange, Mumbai (BSE) in 1986 came out with a stock index that subsequently became the barometer of the Indian stock market.SENSEX is not only scientifically designed but also based on globally accepted construction and review methodology. First compiled in 1986, SENSEX is a basket of 30 constituent stocks representing a sample of large, liquid and representative companies. The base year of SENSEX is 1978-79 and the base value is 100. The index is widely reported in both domestic and international markets through print as well as electronic media.The Index was initially calculated based on the "Full Market Capitalization" methodology but was shifted to the free-float methodology with effect from September 1, 2003. The "Free-float Market Capitalization" methodology of index construction is regarded as an industry best practice globally. All major index providers like MSCI, FTSE, STOXX, S&P and Dow Jones use the Free-float methodology.Due to is wide acceptance amongst the Indian investors; SENSEX is regarded to be the pulse of the Indian stock market. As the oldest index in the country, it provides the time series data over a fairly long period of time (From 1979 onwards). Small wonder, the SENSEX has over the years become one of the most prominent brands in the country.The growth of equity markets in India has been phenomenal in the decade gone by. Right from early nineties the stock market witnessed heightened activity in terms of various bull and bear runs. The SENSEX captured all these events in the most judicial manner. One can identify the booms and busts of the Indian stock market through SENSEX.SENSEX Calculation MethodologySENSEX is calculated using the "Free-float Market Capitalization" methodology. As per this methodology, the level of index at any point of time reflects the Free-float market value of 30 component stocks relative to a base period. The market capitalization of a company is determined by multiplying the price of its stock by the number of shares issued by the company. This market capitalization is further multiplied by the free-float factor to determine the free-float market capitalization.The base period of SENSEX is 1978-79 and the base value is 100 index points. This is often indicated by the notation 1978-79=100. The calculation of SENSEX involves dividing the Free-float market capitalization of 30 companies in the Index by a number called the Index Divisor. The Divisor is the only link to the original base period value of the SENSEX. It keeps the Index comparable over time and is the adjustment point for all Index adjustments arising out of corporate actions, replacement of scrips etc. During market hours, prices of the index scrips, at which latest trades are executed, are used by the trading system to calculate SENSEX every 15 seconds and disseminated in real time.Dollex-30BSE also calculates a dollar-linked version of SENSEX and historical values of this index are available since its inception. (For more details click ‘Dollex series of BSE indices’)Understanding Free-float MethodologyConcept:Free-float Methodology refers to an index construction methodology that takes into consideration only the free-float market capitalization of a company for the purpose of index calculation and assigning weight to stocks in Index. Free-float market capitalization is defined as that proportion of total shares issued by the company that are readily available for trading in the market. It generally excludes promoters' holding, government holding, strategic holding and other locked-in shares that will not come to the market for trading in the normal course. In other words, the market capitalization of each company in a Free-float index is reduced to the extent of its readily available shares in the market.In India, BSE pioneered the concept of Free-float by launching BSE TECk in July 2001 and BANKEX in June 2003. While BSE TECk Index is a TMT benchmark, BANKEX is positioned as a benchmark for the banking sector stocks. SENSEX becomes the third index in India to be based on the globally accepted Free-float Methodology.Major advantages of Free-float Methodology:
A Free-float index reflects the market trends more rationally as it takes into consideration only those shares that are available for trading in the market.
Free-float Methodology makes the index more broad-based by reducing the concentration of top few companies in Index. For example, the concentration of top five companies in SENSEX has fallen under the free-float scenario thereby making the SENSEX more diversified and broad-based.
A Free-float index aids both active and passive investing styles. It aids active managers by enabling them to benchmark their fund returns vis-à-vis an investable index. This enables an apple-to-apple comparison thereby facilitating better evaluation of performance of active managers. Being a perfectly replicable portfolio of stocks, a Free-float adjusted index is best suited for the passive managers as it enables them to track the index with the least tracking error.
Free-float Methodology improves index flexibility in terms of including any stock from the universe of listed stocks. This improves market coverage and sector coverage of the index. For example, under a Full-market capitalization methodology, companies with large market capitalization and low free-float cannot generally be included in the Index because they tend to distort the index by having an undue influence on the index movement. However, under the Free-float Methodology, since only the free-float market capitalization of each company is considered for index calculation, it becomes possible to include such closely held companies in the index while at the same time preventing their undue influence on the index movement.
Globally, the Free-float Methodology of index construction is considered to be an industry best practice and all major index providers like MSCI, FTSE, S&P and STOXX have adopted the same. MSCI, a leading global index provider, shifted all its indices to the Free-float Methodology in 2002. The MSCI India Standard Index, which is followed by Foreign Institutional Investors (FIIs) to track Indian equities, is also based on the Free-float Methodology. NASDAQ-100, the underlying index to the famous Exchange Traded Fund (ETF) - QQQ is based on the Free-float Methodology.Definition of Free-float:
Share holdings held by investors that would not, in the normal course come into the open market for trading are treated as 'Controlling/ Strategic Holdings' and hence not included in free-float. In specific, the following categories of holding are generally excluded from the definition of Free-float:
Holdings by founders/directors/ acquirers which has control element
Holdings by persons/ bodies with "Controlling Interest"
Government holding as promoter/acquirer
Holdings through the FDI Route
Strategic stakes by private corporate bodies/ individuals
Equity held by associate/group companies (cross-holdings)
Equity held by Employee Welfare Trusts
Locked-in shares and shares which would not be sold in the open market in normal course.The remaining shareholders would fall under the Free-float category.Determining Free-float factors of companies:
BSE has designed a Free-float format, which is filled and submitted by all index companies on a quarterly basis with the Exchange. (Format available on www.bseindia.com) The Exchange determines the Free-float factor for each company based on the detailed information submitted by the companies in the prescribed format. Free-float factor is a multiple with which the total market capitalization of a company is adjusted to arrive at the Free-float market capitalization. Once the Free-float of a company is determined, it is rounded-off to the higher multiple of 5 and each company is categorized into one of the 20 bands given below. A Free-float factor of say 0.55 means that only 55% of the market capitalization of the company will be considered for index calculation.Free-float Bands:
% Free-Float
Free-Float Factor
% Free-Float
Free-Float Factor
>0 – 5%
0.05
>50 – 55%
0.55
>5 – 10%
0.10
>55 – 60%
0.60
>10 – 15%
0.15
>60 – 65%
0.65
>15 – 20%
0.20
>65 – 70%
0.70
>20 – 25%
0.25
>70 – 75%
0.75
>25 – 30%
0.30
>75 – 80%
0.80
>30 – 35%
0.35
>80 – 85%
0.85
>35 – 40%
0.40
>85 – 90%
0.90
>40 – 45%
0.45
>90 – 95%
0.95
>45 – 50%
0.50
>95 – 100%
1.00Index Closure Algorithm
The closing SENSEX on any trading day is computed taking the weighted average of all the trades on SENSEX constituents in the last 30 minutes of trading session. If a SENSEX constituent has not traded in the last 30 minutes, the last traded price is taken for computation of the Index closure. If a SENSEX constituent has not traded at all in a day, then its last day's closing price is taken for computation of Index closure. The use of Index Closure Algorithm prevents any intentional manipulation of the closing index value.Maintenance of SENSEXOne of the important aspects of maintaining continuity with the past is to update the base year average. The base year value adjustment ensures that replacement of stocks in Index, additional issue of capital and other corporate announcements like 'rights issue' etc. do not destroy the historical value of the index. The beauty of maintenance lies in the fact that adjustments for corporate actions in the Index should not per se affect the index values.The Index Cell of the exchange does the day-to-day maintenance of the index within the broad index policy framework set by the Index Committee. The Index Cell ensures that SENSEX and all the other BSE indices maintain their benchmark properties by striking a delicate balance between frequent replacements in index and maintaining its historical continuity. The Index Committee of the Exchange comprises of experts on capital markets from all major market segments. They include Academicians, Fund-managers from leading Mutual Funds, Finance-Journalists, Market Participants, Independent Governing Board members, and Exchange administration.On-Line Computation of the Index:During market hours, prices of the index scrips, at which trades are executed, are automatically used by the trading computer to calculate the SENSEX every 15 seconds and continuously updated on all trading workstations connected to the BSE trading computer in real time.Adjustment for Bonus, Rights and Newly issued Capital:The arithmetic calculation involved in calculating SENSEX is simple, but problem arises when one of the component stocks pays a bonus or issues rights shares. If no adjustments were made, a discontinuity would arise between the current value of the index and its previous value despite the non-occurrence of any economic activity of substance. At the Index Cell of the Exchange, the base value is adjusted, which is used to alter market capitalization of the component stocks to arrive at the SENSEX value.The Index Cell of the Exchange keeps a close watch on the events that might affect the index on a regular basis and carries out daily maintenance of all the 14 Indices.
Adjustments for Rights Issues:When a company, included in the compilation of the index, issues right shares, the free-float market capitalisation of that company is increased by the number of additional shares issued based on the theoretical (ex-right) price. An offsetting or proportionate adjustment is then made to the Base Market Capitalisation (see 'Base Market Capitalisation Adjustment' below).
Adjustments for Bonus Issue:When a company, included in the compilation of the index, issues bonus shares, the market capitalisation of that company does not undergo any change. Therefore, there is no change in the Base Market Capitalisation, only the 'number of shares' in the formula is updated.
Other Issues:Base Market Capitalisation Adjustment is required when new shares are issued by way of conversion of debentures, mergers, spin-offs etc. or when equity is reduced by way of buy-back of shares, corporate restructuring etc.
Base Market Capitalisation Adjustment:
The formula for adjusting the Base Market Capitalisation is as follows:
New Market Capitalisation
New Base Market Capitalisation
=
Old Base Market Capitalisation
x
---------------------------------------
Old Market Capitalisation
To illustrate, suppose a company issues right shares which increases the market capitalisation of the shares of that company by say, Rs.100 crores. The existing Base Market Capitalisation (Old Base Market Capitalisation), say, is Rs.2450 crores and the aggregate market capitalisation of all the shares included in the index before the right issue is made is, say Rs.4781 crores. The "New Base Market Capitalisation " will then be:
2450 x (4781+100)
--------------------------
=
Rs.2501.24 crores
4781
This figure of 2501.24 will be used as the Base Market Capitalisation for calculating the index number from then onwards till the next base change becomes necessary.
Back
SENSEX - Scrip selection criteria:
The general guidelines for selection of constituents in SENSEX are as follows:
Listed History:The scrip should have a listing history of at least 3 months at BSE. Exception may be considered if full market capitalisation of a newly listed company ranks among top 10 in the list of BSE universe. In case, a company is listed on account of merger/ demerger/ amalgamation, minimum listing history would not be required.
Trading Frequency:The scrip should have been traded on each and every trading day in the last three months. Exceptions can be made for extreme reasons like scrip suspension etc.
Final Rank:The scrip should figure in the top 100 companies listed by final rank. The final rank is arrived at by assigning 75% weightage to the rank on the basis of three-month average full market capitalisation and 25% weightage to the liquidity rank based on three-month average daily turnover & three-month average impact cost.
Market Capitalization Weightage:The weightage of each scrip in SENSEX based on three-month average free-float market capitalisation should be at least 0.5% of the Index.
Industry Representation:Scrip selection would generally take into account a balanced representation of the listed companies in the universe of BSE.
Track Record:In the opinion of the Committee, the company should have an acceptable track record.Index Review Frequency:The Index Committee meets every quarter to discuss index related issues. In case of a revision in the Index constituents, the announcement of the incoming and outgoing scrips is made six weeks in advance of the actual implementation of the revision of the Index.
Back
History of replacement of scrips in SENSEX
Date
Outgoing Scrips
Replaced by
01.01.1986
Bombay Burmah
Voltas
Asian Cables
Peico
Crompton Greaves
Premier Auto.
Scinda
G.E.Shipping
03.08.1992
Zenith Ltd.
Bharat Forge
19.08.1996
Ballarpur Inds.
Arvind Mills
Bharat Forge
Bajaj Auto
Bombay Dyeing
BHEL
Ceat Tyres
BSES
Century Text.
Colgate
GSFC
Guj. Amb. Cement
Hind. Motors
HPCL
Indian Organic
ICICI
Indian Rayon
IDBI
Kirloskar Cummins
IPCL
Mukand Iron
MTNL
Phlips
Ranbaxy Lab.
Premier Auto
State Bank of India
Siemens
Steel Authority of India
Voltas
Tata Chem
16.11.1998
Arvind Mills
Castrol
G. E. Shipping
Infosys Technologies
IPCL
NIIT Ltd.
Steel Authority of India
Novartis
10.04.2000
I.D.B.I
Dr. Reddy’s Laboratories
Indian Hotels
Reliance Petroleum
Tata Chem
Satyam Computers
Tata Power
Zee Telefilms
08.01.2001
Novartis
Cipla Ltd.
07.01.2002
NIIT Ltd.
HCL Technologies
Mahindra & Mahindra
Hero Honda Motors Ltd.
31.05.2002
ICICI Ltd.
ICICI Bank Ltd.
10.10.2002
Reliance Petroleum Ltd.
HDFC Ltd.
10.11.2003
Castrol India Ltd.
Bharti-Tele-Ventures Ltd.
Colgate Palomive (India) Ltd.
HDFC Bank Ltd.
Glaxo Smithkline Pharma. Ltd.
ONGC Ltd.
HCL Technologies Ltd.
Tata Power Company Ltd.
Nestle (India) Ltd.
Wipro Ltd.
19.05.2004
Larsen & Toubro Ltd.
Maruti Udyog Ltd.
27.09.2004
Mahanagar Telephone Nigam Ltd.
Larsen & Toubro Ltd.
06.06.2005
Hindustan Petroleum Corp Ltd.
National Thermal Power Corpn. Ltd.
Zee Telefilms Ltd.
Tata Consultancy Services Ltd.
12.06.2006
Tata Power Ltd.
Reliance Communiation Ventures Ltd.
09.07.2007
Hero Honda Motors Ltd.
Mahindra & Mahindra Ltd.
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