Cross-Layer Cooperative Transmission for Improving Throughput in Wireless Relay Networks

With the rapid increase of mobile devices, wireless networks face spectrum exhaustion and insufficient bandwidth utilization problems. Cooperative communication is a promising approach to improve throughput in wireless relay networks. Recent researches mainly focus on cooperative communication methods in PHY or MAC layers separately to improve data transmission performance. Considering a typical video surveillance scenario in WLAN, this paper propose a cross-layer cooperative transmission scheme from the terminal to the wireless access point with help of another terminal as the relay node. The relay and direct channel states are estimated first based on finite state Markov channel (FSMC) model before transmission. The link with larger effective bandwidth between the relay and direct transmission channels is selected as the actual transmission channel. The simulation experiments are implemented in 802.11b framework. The experimental results indicate that the proposed scheme can achieve a gain of about 11% in throughput with channel average signal-to-noise ratio (SNR) equal to 5 dB, and about 19% with average SNR equal to 10 dB. It shows that the proposed scheme can improve transmission performance effectively, and when the channel situation gets better, the gain becomes more notable.