DEVELOPMENT OF A SYSTEM THAT WOULD ALLOCATE RESOURCES EVENLY OVER A WIRELESS NETWORK DURING MULTICAST SESSIONS. A RESEARCH PROJECT MATERIAL ON COMPUTER SCIENCE EDUCATION
1.1 BACKGROUND OF THE STUDY
Multicast sessions are expected to be a common form of traffic in emerging mobile ad hoc networks. However, the recently developed theory for fair resource allocation in Mobile Ad Hoc Networks (MANETs) (Lin & Shroff 2004; Eryilmaz & Srikant 2005, 2006; Stolyar 2005, 2006; Neely et al. 2005) only addresses the case of unicast flows. Other than developing appropriate notation, it is somewhat straightforward to extend the theory to multicast sessions if one assumes that data is delivered to all the receivers in a multicast group at the same rate. Such a form of multicast is called single-rate multicast. On the other hand, there are many video applications which allow layered-transmission so that different receivers can subscribe to different numbers of layers and receive different qualities of the same video, depending upon the congestion level in their respective neighborhoods. Moreover, in wireless networks, due to varying signal strengths at different receivers, it may not be desirable or feasible to deliver data at the same rate to all the receivers in a multicast group. Thus, it is important to extend the optimization-based theory to handle multi-rate multicast sessions, i.e., multicast sessions where different receivers are allowed to receive at different rates. Such an extension is not immediate as in the case of single-rate multicast.
In the last few years there has been significant growth in the area of wireless communication. Institute of Electrical and Electronics Engineering (IEEE) 802.16 (WiMAX) is the network which is designed for providing high speed wide area broadband wireless access. It consists of a base station (BS) and multiple subscriber station (SSs). BS transmits data to the SSs through broadcast channel. The SSs are linked to BS through multiple access channels. IEEE 802.16 standard utilize new nodes called relay stations (RSs). The RSs relay data between the BS and the SSs in upward and downward direction. WiMAX is an emerging wireless technology for creating multi-hop Mesh network.