Goodput Analysis and Link Adaptation for IEEE 802.11a Wireless LANs
IEEE Transactions on Mobile Computing
The impact of link-layer retransmissions on video streaming in wireless mesh networks
Proceedings of the 4th Annual International Conference on Wireless Internet
MAC layer support for delay tolerant video transport in disruptive MANETs
NETWORKING'11 Proceedings of the 10th international IFIP TC 6 conference on Networking - Volume Part I
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Multimedia transmission over wireless local area networks is challenging due to the varying nature of the wireless channel as well as the inherent difference between multimedia and data traffic. In the MAC layer, a single bit error in the packet can lead to the entire packet being discarded. This results in a higher packet error rate for larger payload sizes. Retransmission due to packet errors causes the contention window to double, and this leads to a decrease in throughput if the wireless channel does not improve for the retransmitted packets. Hence, throughput is a function of packet payload length as well as the maximum number of allowable retransmissions. In this paper, we investigate the effect of payload length adaptation and retransmissions on the throughput and capacity of multimedia users. Numerical results and simulations reveal that careful payload adaptation significantly improves the throughput performance at low signal to noise ratios (SNRs). It is also observed that excessive retransmissions reduce the effective throughput, thereby decreasing the capacity of multimedia users in the presence of data users. Since multimedia traffic is more latency constrained and less error constrained, by carefully selecting the payload length and maximum number of allowable retransmissions based on the channel conditions, a greater number of multimedia users can be supported.