FMAC: Fair Mac Protocol for Achieving Proportional Fairness in Multi-Rate WSNs

Abstract

In a multi-rate wireless environment, slow nodes occupy the channel for longer time than fast nodes and thus the total throughput of the network will be reduced. In this research, we study the problem of fairness in multi-rate wireless sensor networks. To improve the fairness, we propose a new protocol, FMAC (Fair MAC protocol) that is based on IEEE 802.11 MAC protocol to achieve proportional fairness between all nodes. FMAC protocol includes medium delay periods within Backoff algorithm to utilize the idle slots of time and reduce the number of collisions and then number of retransmissions, and thus reducing the energy consumption, which is very critical in wireless sensor networks. The experimental results show that transmissions become faster with less collisions and power consumption when applying FMAC, while the aggregated throughput and proportional fairness are increased. The detailed performance evaluation and comparisons are provided using the simulation.

Instantaneous Fairness of TCP in Heterogeneous Traffic Wireless LAN Environments

“…Since long-term fairness covers only the average behavior, fairness could be broken in a short interval. For stronger fairness, researchers have also studied instantaneous fairness or short-term fairness [13]. Analyzing fairness at any instance requires the description of each source's throughput as a function of time, which can be very complicated in a general network and traffic environment.…”