Congestion control in wireless links based on selective delivery of erroneous packets

Traditionally, congestion control in packet networks is performed by reducing the transmission rate when congestion is detected, in order to cut down the traffic that overwhelms the capacity of the network. However, if the bottleneck is a wireless link, congestion is often cumulated because of retransmissions derived from bit errors. In this case, it might be beneficial to allow delivery of partly corrupted packets up to the application layer instead of reducing the transmission rate. This would decrease the number of retransmissions in the link layer and therefore relieve congestion, but at the cost of bit errors appearing in the packet payload. In this paper, we study a congestion control mechanism for streaming applications that combines traditional congestion control with selective link layer partial checksumming allowing bit errors in the less sensitive parts of data. We have compared the performance of the proposed mechanism against traditional congestion control with a simulation study. The results show that the proposed approach can improve the overall performance both by increasing the throughput over the wireless and improving the video quality in terms of peak signal-to-noise ratio (PSNR) by up to 8 dB, depending on the error conditions and the content.