IEEE : Institute of Electrical and Electronics Engineers, founded in 1884 as the AIEE. In 1963 AIEE merged with IRE to form IEEE.
IEEE is an organization composed of engineers, scientists, and students. The IEEE is best known for developing standards for the computer and electronics industry. In particular, the IEEE 802 standards for local-area networks are widely followed.
OFDM: Orthogonal Frequency Division Multiplexing
An FDM modulation technique for transmitting large amounts of digital data over a radio wave.
OFDM works by splitting the radio signal into multiple smaller sub-signals that are then transmitted simultaneously at different frequencies to the receiver.
OFDM reduces the amount of crosstalk in signal transmissions. 802.11a WLAN, 802.16 and WiMAX technologies use OFDM.
Wimax technologies are primarily based on IEEE 802.16a and 802.16REVd (collectively referred to as 802.16-2004), and 802.16e (802.16-2005). (Joel B & Jimmy D, 2006 pp 43)
It was required because there was:
Lack of standardization
Range & Speed
High CPE Costs
IEEE 802.16 Specifications
Range - 30-mile (50-km) radius from base station
Speed - 70 Mbps
Line-of-sight not needed between user and base station
Frequency bands - 2 to 11 GHz and 10 to 66 GHz (licensed and unlicensed bands)
… IEEE standards
802.20 MobileFi or Mobile Broadband Wireless Access: It established in December 2002 that originally planned to define mobile broadband wireless access (MBWA), with 802.16 (WiMAX) addressing fixed-location access. 802.16e (Mobile WiMAX) is now an alternative service. In June 2006 the IEEE suspended 802.20 activities temporarily because of various irregularities in the proceedings. 802.21: The IEEE 802.21 working group, which began in early 2004, is developing standards and protocols that support mobile communication handover (passing control from one base station to another) and interoperability between similar and dissimilar networks. This work includes 802-type networks such as Wi-Fi (802.11), Bluetooth (802.15.1), and WiMAX (802.16) as well as non-802 networks such as those for 2.5G/3G mobile cellular communications. The standard is expected to enable mobile devices to determine when to switch from 802.11 to cdma2000, for example, based on their current radio environment. One goal is to allow VoIP and other office applications to move seamlessly to the field and operate there equally well. No timeframe is established yet for completing this standard. Global Area Network: The final step in the area network scale is the global area network (GAN). The proposal for GAN is IEEE 802.20. A true GAN would work a lot like today's cell phone networks, with users able to travel across the country and still have access to the network the whole time. This network would have enough bandwidth to offer Internet access comparable to cable modem service, but it would be accessible to mobile, always-connected devices like laptops or next-generation cell phones. … IEEE standards
SUMMARY OF IEEE SPECIFICATIONS No native support for IP, so it does not support TCP/IP and wireless LAN applications well. Not originally created to support wireless LANs. Best suited for connecting PDAs, cell phones and PCs in short intervals. FHSS Up to 2Mbps in the 2.45GHz band Bluetooth Commonly referred to as WiMAX or less commonly as WirelessMAN or the Air Interface Standard, IEEE 802.16 is a specification for fixed broadband wireless metropolitan access networks (MANs) OFDM Added support for the 2 to 11 GHz range. IEEE 802.16a (WiMAX) Commonly referred to as WiMAX or less commonly as WirelessMAN or the Air Interface Standard, IEEE 802.16 is a specification for fixed broadband wireless metropolitan access networks (MANs) OFDM Specifies WiMAX in the 10 to 66 GHz range IEEE 802.16 (WiMAX) "Wi-Fi Certified." May replace 802.11b. Improved security enhancements over 802.11. Compatible with 802.11b. 14 channels available in the 2.4GHz band (only 11 of which can be used in the U.S. due to FCC regulations) with only three non-overlapping channels. OFDM above 20Mbps, DSSS with CCK below 20Mbps Up to 54Mbps in the 2.4GHz band IEEE 802.11g Wi-Fi "Wi-Fi Certified." Not interoperable with 802.11a. Requires fewer access points than 802.11a for coverage of large areas. Offers high-speed access to data at up to 300 feet from base station. 14 channels available in the 2.4GHz band (only 11 of which can be used in the U.S. due to FCC regulations) DSSS with CCK Up to 11Mbps in the 2.4GHz band IEEE 802.11b Wi-Fi "Wi-Fi Certified." Eight available channels. Less potential for RF interference than 802.11b and 802.11g. Better than 802.11b at supporting multimedia voice, video and large-image applications in densely populated user environments. OFDM Up to 54Mbps in the 5GHz band IEEE 802.11a Wi-Fi This specification has been extended into 802.11b. FHSS or DSSS Up to 2Mbps in the 2.4GHz band IEEE 802.11 Pros/Cons & More Info Modulation Scheme Data Rate Standard
A WiMAX tower station can connect directly to the Internet using a high-bandwidth, wired connection (for example, a T3 line).
It can also connect to another WiMAX tower using a line-of-sight, microwave link (backhaul), along with the ability of a single tower to cover up to 3,000 square miles, is what allows WiMAX to provide coverage to remote rural areas. This way WiMAX actually can provide two forms of wireless service:
Non-line-of-sight , WiFi sort of service, where a small antenna on your computer connects to the tower, using a lower frequency range -- 2 GHz to 11 GHz (similar to WiFi). Lower-wavelength transmissions are not as easily disrupted by physical obstructions -- they are better able to diffract, or bend, around obstacles.
Line-of-sight service, where a fixed dish antenna points straight at the WiMAX tower from a rooftop or pole. The line-of-sight connection is stronger and more stable, so it's able to send a lot of data with fewer errors. Line-of-sight transmissions use higher frequencies , with ranges reaching a possible 66 GHz. At higher frequencies, there is less interference and lots more bandwidth.
WiFi-style access will be limited to a 4-to-6 mile radius (perhaps 25 square miles or 65 square km of coverage, which is similar in range to a cell-phone zone).
Through the stronger line-of-sight antennas, the WiMAX transmitting station would send data to WiMAX-enabled computers or routers set up within the transmitter's 30-mile radius (2,800 square miles or 9,300 square km of coverage). This is what allows WiMAX to achieve its maximum range.
Q. What companies are involved with WiMAX? (link to Forum list)by Michael Wolleben — last modified 2007-03-19 12:38 PM
As of last count, the WiMAX Forum membership counted 426 companies with many other firms evaluating the technology as a possible fit for their business and technical models. A complete list of WiMAX Forum members can be found on its site. WiMAX Forum ™ Members.( /www.wimaxforum.org)
Total of 66 countries are in the process of WiMAX Deployment, including Pakistan. For a list of operators in the countries click list of countries deploying WiMAX
WiMAX has a communication range of up to 30 miles. This can cover over 2800 square miles enough to blanket an entire city.
By using a WiMAX system, companies/ residents no longer have to rip up buildings or streets or lay down expensive cables.
WiMAX can provide shared data rates of up to 70 Mb/s, to support more than 60 businesses at once with T1-type connectivity.
It can also support over a thousand homes at 1 Mb/s DSL-level connectivity.
Service WiMAX can provide users with two forms of wireless service:
Non Line-of-Sight :
Operates at 2 to 11 GHz, which at a lower level frequency has the ability to bend around obstacles more easily. A small antenna on a computer connects to the tower and is backwards compatible with existing Wi-Fi technologies.
Can go as high as 66 GHz since the signal is stronger and more stable, which leads to greater bandwidth. Here, a fixed dish antenna points straight at the tower or for communication between tower to tower.
Base stations will cost under $20,000 but will still provide customers with T1-class connections.
(1) Wateen - which is using WiMAX solution from Motorola and its cable/fiber network to offer triple play of phone, TV and broadband. Trials have been extended for over a year. Most aggressive to market their bundled solutions, they have started advertising without providing pricing and availability information.
(2) Mobilink - has formed a new entity called Link Dot Net (LDN) to focus on broadband market. WiMAX infrastructure was piloted by Mobilink in 3 cities and a recently issued RFP has generated 7 proposals to cover 5 major metros , including in-building coverage for high value business areas. Malaysia’s Dancom , which conducted early trials of WiMAX in Karachi , was acquired by Mobilink’s LDN in 2007 . Mobilink also bought DV Com and its licenses.
(3) Burraq Telecom - which was acquired by ACT consortium which includes Qatar Telecom and Clearwire Corporation , an American operator providing WiMAX services in 10 countries, also plans to offer WiMAX .
The pricing has not been announced by these companies yet. Business users in Pakistan desperately need reliable broadband and are the desired customers because of their high affordability levels. Consumer market is different as demand varies by demographics’ low price is the dominating success factor.
Wimax is expected to help the ‘last mile’ problem prevalent in many 3rd world countries and underserved areas in developed countries where wireline infrastructure is limited and that would be too expensive and time consuming to deploy.
In addition to this Wimax provides a significant improvement over existing technologies in speed, range & cost of deployment. This will result in availability of Broad wireless services to a large number of consumers & SME’s.
The better bandwidth and range would also result in new applications availability, like online gaming, video on demand, VPLS & Voip, this in turn will help in reduction of bandwidth costs.
Wimax will not however be as ‘disruptive technology’ as suggested by some industry experts, at least not for another 3-4 years until 802.16e is fully standardized and mobile Wimax devices becomes common place.
For next few years Wimax technology will complement current technologies like Wi-Fi & 3G, although gradually Wimax might prove to be a disruptive technology for wireline technologies like DSL, specially when demand for broadband internet and higher bandwidth applications increases.
On the whole Wimax will have a positive effect for the consumers, through standardization, lower cost, better speed & range. Although there are legitimate impediments surrounding it, like standardization, government regulatory policies, timelines etc, Wimax will play a critical role in making wireless broadband a more globally ubiquitous service, in mostly developing countries, having less or no telecom infrastructure available.
Thank you For details /references, contact: [email_address] 0345-2001058