On video multicast over wireless LANs

In this paper, we explore and analyze the feasibility of current generation IEEE 802.11b wireless networks to sustain video multicast applications. We assess bandwidth efficiency to transport packets of various sizes over 802.11b WLAN in distributed coordination function (DCF) mode and derive corresponding theoretical maximum data rates. Due to the overhead associated with the different protocol layers, the efficiency of transport can vary widely with different packet sizes. By controlled WLAN experimentation the effect of this phenomenon on video traffic is studied. Application to MPEG4-AVC streams show that the packet overhead in 802.11 DCF mode causes a significant bottleneck for simultaneous multicast streams. We conclude with several suggestions to alleviate this problem including operating in 802.11 PCF mode, using a statistical multiplexer and improving design of queues in the wireless access point