Performance evaluation of video streaming over multi-hop wireless local area networks

IEEE 802.11 WLAN is preferred for IPTV in-home distribution, but the achievable throughput and coverage are still limited due to the high attenuation and interference in a household environment. Through our measurement study with a WDS-based multi-hop wireless testbed, we have found that it is possible for multi-hop wireless networks to increase the coverage and improve the video streaming performance at the same time. To analyze the throughput of IEEE 802.11 multihop wireless networks, we propose an extended two-dimensional Markov-chain model in this paper. Different from existing work, our model takes the retry limit and post-backoff stage into account to better capture the behavior of IEEE 802.11 MAC protocols in a non-ideal channel and with non-persistent traffic. The throughput analysis is validated by network simulation with extended lower and upper-layer simulation modules. The achievable throughput gives an upper bound of the video streaming performance, which is further validated by our H.264-based video streaming simulation with application-layer performance metrics. The results correspond to the observation we had on the multi-hop testbed. Further, this paper also provides some guidance on how to achieve the optimal balance for a given scenario, which is important when deploying video streaming services with end-to-end quality-of-service provisioning.