Discussion 1 - Question 2

           Do research on the Web on wireless communications standards for Mans often called WIMAX. What is it current status of the various standards and what are the current major issues? Write a report on what you found.

WiMAX stand for Worldwide Interoperability for Microwave Access and it is a communications technology that uses radio spectrum to transmit tens of megabits per second in bandwidth between digital devices such as laptop computers. WiMAX brings the ability to transmit over far greater distances and to handle much more data where similar to Wifi.

These standards are issued by IEEE 802.16 work group that originally covered the wireless local loop (WLL) technologies in the 10.66 GHz radio spectrum, which where later extended through amendment projects to include both licensed and unlicensed spectra from 2 to 11 GHz.

The chart of various IEEE 802.16 Standards related to WiMax.

	802.16	802.16a	802.16e
Spectrum	10 - 66 GHz	2 – 11 GHz	<6 GHz
Configuration	Line of Sight	Non  Line of Sight	Non Line of Sight
Bit Rate	32 to 134 Mbps (28 MHz Channel)	70 or 100 Mbps (20 MHz Channel	Up to 15 Mbps
Modulation	QPSK, 16-QAM, 64-QAM	256 Sub-Carrier OFDM using QPSK, 16-QAM, 64-QAM, 256-QAM	Same as 802.16a
Mobility	Fixed	Fixed	75 MPH
Channel Bandwidth	20,25,28 MHz	Selectable 1.25 to 20 MHz	5 MHz (Planned)
Typical Cell Radius	1 -3 miles	3 – 5 miles	1 – 3 miles
Completed	Dec 2001	Jan 2003	2nd half of 2005

           

The current major issues are listed below.

Lack of Quality	There are hundreds of people trying to get access at the same tower so due to heavy traffic it is very hard to maintain high quality.
Wimax range	As Wimax offer 70Mbps in range with moving station but in practice it is quite different because it is possible only in specify or ideal circumstances. If a user staying away from the specified environment then speed can drop considerably.
Wimax Bandwidth	If there are a lot of users in one area the speed decreases which may be 2 to 10 Mbps of shared bandwidth. Like other network Bandwidth is collective amongst clients in a specified zone.
Expensive network	Its  installation and operational cost makes the Wimax network collectively high cost network  due to heavy structure, tower, antennas etc
Bad Weather	In rainy season, the quality of services decreases due to the weather condition could interrupt the signal which may cause of bad signal and broadcasting may be stop or interrupted.
Wireless equipments	These equipments may cause of interference and could interfere the broadcasting data or face some compromised speed if there are trying to use much wireless equipment in time Wimax network.
Power consuming	Wimax network is very heavy in structure therefore need much electrical support for running the overall network.
Data Rate	The data rate of Wimax as compared to other network such as fiber optics, satellite, cables etc are very slow.