After completing this experiment you will be able to:
- Understand about WiMAX network,standards,limitations,working principles and differentiate from Wi-Fi network
- Identifying the different issues related to WiMAX. Solve and simulate the problems with the open source network simulator NS2
- Analyze the WiMAX communication range in the presence of the access point (AP) and the base station (BS)
Around 3.00 hours
WiMAX stands [i] for Worldwide Interoperability for Microwave Access (AXess). It is a broadband wireless point-to-multipoint specification from the IEEE 802.16 working group. It was developed by Institute of Electrical and Electronics Engineers (IEEE) in June 2001. WiMAX is designed to operate as a wireless MAN (Metropolitan Area Network). It is a telecommunications protocol that provides fixed and mobile internet access.
- The IEEE 802.16 WiMAX standard specified for the 10 to 66 GHz ranges.[i]
- 802.16d was updated by 802.16a in 2004 to 802.16-2004. It added specification for the 2 to 11 GHz range. 802.16d, it also known as "fixed WiMAX”.
- 802.16e was updated by 802.16d in December 2005. It is known as "roaming and mobile WiMAX" and uses scalable orthogonal frequency-division multiplexing (OFDM). It has 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
- 802.16m (New) The Institute of Electrical and Electronics Engineers is expected this year in 2011 to provide final approval for the 802.16m standard, also known as "WiMAX 2" [iii] . However it plans on testing out 802.16m sometime next year in the hopes of deploying it in 2012.
Following table shows the differentiate among IEEE 802.16,802.16d and 802.16e
llustration of different WiMAX standards
Comparison of Wi-Fi and WiMAX
The following table shows how WiFi is differentiate from WiMAX
WiFi vs WiMAX [ii]
How WiMAX works ?
WiMAX is possible through broadband access to DSL lines. The working method of WiMAX is different from Wi-Fi network, because Wi-Fi system can be connected via LAN card or router, while the connectivity of WiMAX network constitutes of two parts in which one is WiMAX tower or booster also known as WiMAX base station and second is WiMAX receiver or Customer Premise Equipment (CPE).
WiMAX technology providers build a network with the help of towers that enable communication access over many miles. The broadband service of WiMAX technology is available in coverage areas. The coverage areas of WiMAX technology separated in series of over lied areas called channel.
When a user sends data from one location to another, the wireless connection is transferred from one cell to another cell. When signal transmit form user to WiMAX base station or base station to user (WiMAX receiver), the wireless channel faces many attenuation such as fraction, reflection, refraction, wall obstruction etc. These all attenuation may cause of distorted, and split toward multi path. The target of WiMAX receiver is to rebuild the transmitted data perfectly to make possible reliable data transmission.
Limitations of WiMAX
WiMax cannot provide highest performance over 50 kilometers. As the distance increases, bit error rate reduces the performance. Reducing distance to less than 1km allows a device to operate at higher bit rate. A user closer to base station gets better speed at around 30mbps.
As an available bandwidth is shared between no. of users, performance depends on number of active users connecting to that base station. So this needs a use of Quality of Service (QOS) mechanism to provide a minimum guaranteed throughput.