A Novel Fixed Contention Window Backoff Algorithm for IEEE 802.11 WLAN

The network throughput will decrease dramatically and collision rate increases severely when active nodes increase in WLAN. Breaking through the limitation of the Binary Exponential Backoff algorithms, we provide a new backoff algorithm which utilizes the linear contention window based on the node numbers. To attain better performance, we derive that the contention window is selected as an approximate linear function of number of active nodes. Consequently, for large number of nodes, the collision probability is independent of contention window and the node numbers. The theoretical analysis and simulation results show that the algorithm can maintain the network throughput effectively.