Wichita State University
Over the last few decades, the telecommunication industries has transited from fixed to mobile wireless solutions to provide their subscriber with exceptional services. To overcome these issues many telecommunication industries has been deploying Worldwide Interoperability for Microwave Access (WiMAX) as a last mile solution. The only backbone infrastructure for most business environment to deploy WiMAX is the wireless broadband connection, thus will be best possible solution ever. WiMAX, also known as IEEE 802.16 standard is the most recent state of the art technology that promise to offer high data rate for both fixed and mobile users.
The purpose of this thesis is to study the technical aspect of WiMAX and IEEE 802.11 standard also known as wireless fidelity (Wi-Fi). The report contains the various features of different IEEE 802.XX standard from its initial phase to final phase and its technical enhancement over the years. The comparative study is done between the WiMAX and Wi-Fi to analyze the better possible solution to overcome the current user demand.
WiMAX: A Last Mile Solution In Wireless Communication.
Since the demand and utilization of digital network is much higher these days, the telecommunication industries are struggling to design and implement the newer communication network with higher capacity and load to cope with the current situation. These industries highly utilizes the wireless communications technologies that has emerged rapidly and expanded stunningly during the last few decades. The application of cellular mobile technology, wireless local area network (WLAN) and the exponential growth of Internet has made possible to obtain the wireless network of higher capacity and bandwidth.
WiMAX incorporates the medium access control (MAC) and physical layer (PHY) protocol of wireless broadband communication network. WiMAX is also defined as metropolitan area network (WMAN), where the end users gets directly connected to the main transmitting station of the wireless service provider (Martin, Li, Pressly & Westall, 2010). It has the integrated features of line of sight(LOS) along with the non line of sight (NLOS) communication which is best possible alternative technology to be deployed in urban areas where cables, DSL or T1 has not yet been implemented. There are other wireless technologies like Wi-Fi. which also provided wireless connectivity to the end users with very low range, mobility, bandwidth and quality of service (QoS). WiMAX is a better solution than Wi-Fi for providing wireless connectivity in urban areas due to its exceptional bandwidth, QoS and mobility.
WiMAX can be compared with many other wireless solutions like Wi-Fi, 3G, Universal Mobile Telecommunication System (UMTS) or Long Term Evolution (LTE). They are all competing technologies and evolving daily with something new. UMTS offers very high mobility but does not provide enough bandwidth for higher data rates. Wi-Fi provides high data rate with very limited mobility. WiMAX on the other hand lies in between Wi-Fi and UMTS, providing sufficient bandwidth and mobility for the end users (Bathich, Baba & Ibrahim, 2012).
As defined by the IEEE computer society there are four protocols defined for the Wi-Fi network, IEEE 802.11a/b/g/n. IEEE.802.11a/g wireless standard offers a maximum throughput of 54 Mbps operating at 5.2/2.4 GHz frequency .IEEE 802.11b offers the maximum data rate of 11 Mbps operating at 2.4 GHz frequency band. These technologies provides indoor coverage of around 100 m radius and outdoor coverage of around 250 m radius having 20 MHz fixed channel bandwidth (Marzuki & Baba, 2011). Wi-Fi can be deployed in two ways, infrastructure mode and ad-hoc mode. In infrastructure mode the end users connect to the Wi-Fi network via. the access point (AP). The AP is responsible for providing IP address, data rate and mobility. In ad-hoc mode each users connect with another without the need of AP. There are many limitations on deploying this technology due to its range, QoS and data rate makes (Bathich et al., 2012). The biggest challenge in Wi-Fi network is that the wireless signal is very sensitive to an external interference which is beyond the control of the system administrator, thus very unreliable to implement. For an example, as the user changes its location or move far from the base station, the data rate starts dropping gradually and finally reaches 0 at certain point which in-turn reduces the QoS which has a great impact on voice and video conferencing. The only advantage of using Wi-Fi is because of the cost associated with its deployment. These practical limitations can be highly reduced with the implementation of WiMAX which has numerous advantages over the Wi-Fi (Chou, Li & Lan, 2009).
WiMAX is one of the best possible wireless broadband solution that incorporates numerous features and deployment flexibility. The prominent features that cannot be ignored are its physical layer based on orthogonal frequency division multiplexing (OFDM), higher bandwidth, QoS, mobility support scalability, adaptive modulation and coding (AMC), link layer retransmission, support for advanced multiple input multiple output (MIMO) antenna technology, security and last but not the least Internet Protocol (IP) based architecture.
According to IEEE, WiMAX is capable of providing service range of up to 30 miles so that the users can connect directly with the base station without requiring the line of sight. It provides a bandwidth of 70 Mbps for downlink and uplink, which is far enough to support more than 50 businesses and thousand homes running simultaneously at a time. As Wi-Fi, the IEEE 802.16 has four different standards, The original standard IEEE 802.16, IEEE 802.16a-2004 (known as fixed WiMAX), IEEE 802.16e-2005 (Known as mobile WiMAX) that operates in the frequency band of 10 to 66 GHz, 2 to 11 GHz and 20 MHz frequency band respectively (Patidar, Dubey, Jain & Kulpariya, 2012 ). Since it operates at higher frequency band, licensing issues comes ahead so, many businesses and companies are interested in deploying 802.16a standard. Beside these three standards, the WiMAX update IEEE 802.16m that supports both the fixed and mobile users is expected to offer a bandwidth of 1Gbps for fixed and 100 Mbps for mobile users (Bathich et al., 2012).
The deployment cost associated with the WiMAX is very high as compared to Wi-Fi because the internet service provider (ISP) will have to deploy the WiMAX tower in various location of the city in order to provide full coverage. This deployment depends on the geographical location and weather condition. Once deployed each WiMAX tower can communicate with other WiMAX tower without the use of wires. This eventually saves the cost associated with the wired implementation and the user can directly communicate with the WiMAX tower form their end-devices like laptop, personal digital assistant (pda), tablets, mobile phones etc. Users do not need to install any wireless devices in their home like Wi-Fi routers or modems and get rid of those clumsy cables hanging all around. With these aspects WiMAX is reliable, scalable and stable backbone network for providing the internet service to their users (Chou et al., 2009).
Since the bandwidth and range associated with WiMAX is very high as compared to the Wi-Fi, thus WiMAX is able to provide very high QoS and is scalable to support enough users without any degradation in the bandwidth. WiMAX is more reliable as its signal is not prone to noise and interference. Thus with all these features WiMAX proves to be the best possible solutions for wireless connectivity specially in urban areas.
Regardless of these exceptional features more efficient research needs to be done for the issues of licensing and the cost associated with the deployment. The frequency band of WiMAX implemented under the legal bandwidth assigned by the government without degrading the quality that it recently provides would be the most challenging aspect of future research. Also more research can be done in future on reducing the manufacturing cost of the semiconductor implemented in the WiMAX devices which eventually helps cost effective deployment of WiMAX.