Adaptive video multicast over wireless LANs

Video streaming over wireless networks is a challenging problem because of limited bandwidth, high bit error rates and fluctuations in channel quality. This paper investigates the problem of video multicast over an infrastructure-mode 802.11b wireless local area network. In particular, a multirate simulcasting model is considered to deal with variations in channel conditions, and both distributed and centralized algorithms are developed for receiver rate adaptation. OPNET simulations are used to validate the algorithms which aim to maximize the user satisfaction index. Simulation results show that the centralized scheme is better than the distributed scheme as it maximizes the aggregate user satisfaction index under the available bandwidth and channel conditions. It is also observed that FEC increases the user satisfaction index when the channel errors are low; however with higher channel errors EEC cannot increase the user satisfaction index. Based on these results, both open and closed loop algorithms have been developed to maximize the received video quality