Utility Maximization Of Layered Video Multicasting For Wireless Systems With AMC

With the rapid development of modern wireless communication technology and the great deployment of wireless data service, researches on high data rate wireless transmission become more and more popular. The adaptive modulation and coding can improve the spectral efficiency of wireless systems, is one of the most important technologies in wireless communication systems. The adaptive modulation is widely applied to many wireless communication systems such as wireless LAN, IMT-2000, and so on. The method adapts the physical layer mode (modulation index, coding rate, etc.) to the channel condition to maximize the channel utilization.Layered video multicasting can be used to accommodate the heterogeneity of users and their receive channels in wired and wireless system. In a wireless system using adaptive modulation and coding (AMC), total utility of all users can be increased by transmitting the video layers over different AMC modes and allocating proper bandwidth to these video layers. In this paper, it is shown that when the utility function is convex, the utility maximization problem can be formulated into a convex optimization problem. Then several important practical issues like limitation of layer numbers and operational layer rates are considered. With these limitations and no convex constraint on utility function, a genetic algorithm (GA) is proposed to maximize the total utility by layer rate allocation and selecting AMC modes to transmit the video layers. A 7-cell cdma2000 HDR system is used in the simulation to show the performance of the proposed methods.