Multi-Hop Collaborative Relay Networks with Consideration of Contention Overhead of Relay Nodes in IEEE 802.11 DCF

In a WLAN setting, the system throughput may be heavily affected by a small number of low data rate clients due to the packet-fairness property provided by IEEE 802.11 DCF. This is regarded as the performance anomaly problem. Client relay is a technology widely adopted to solve this problem. An important issue of client relay is to decide when a client's traffic should be relayed and who relays it. However, the existing protocols fail to consider the overhead introduced by DCF contentions, resulting in an inaccurate performance analysis and lead to wrong decisions for client relay. In this paper, we focus on the performance analysis for multi-hop relay networks with consideration of contention overhead of relay nodes in IEEE 802.11 DCF protocols. The main work of this paper includes: we consider the contention overhead in the performance analytical model of collaborative relay networks. This model is more accurate than the existing models. We present a throughput analytical model that considers different traffic demands of clients for the traffic pattern of relay networks. Extensive simulations have been done in NS-2. The simulation results show that our algorithm is more accurate and achieves higher relay performance, compared with existing methods.