Receiver based contention management: A cross layer approach to enhance performance of wireless networks

Abstract

IEEE 802.11 standards adopted Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) to witness improvements in performance. Supporting, CSMA/CA is found to enhance performance when the transmitters are located within the neighborhood of one another. But, in the presence of multiple flows, the channel state creates an asymmetric distribution of throughput for different flows. Some flows experience high throughput while others suffer with insufficient bandwidth. To address this problem, Receiver Based Contention Management Scheme (RBCMS) approach is proposed based on collisions sensed by the receiver. RBCMS makes use of RRTS (Request for RTS) packets and also ensures that only the required number of RRTS packets are used to minimize the control overhead. In RBCMS, the current channel status is estimated by Success Ratio (SR) parameter by which contention and congestion are effectively controlled. The potential receiver sends SR value via packets and that is utilized by the sender to estimate network condition in and around the receiver.Accordingly, Contention Window (CW) size in MAC layer and the procedures of congestion avoidance and slow start in transport layer are intensified. The NS3 simulation results obtained in terms of fairness, throughput, delay etc. reveal the performance enhancements of RBCMS over Advanced Backoff Algorithm (ABA) and BEB.