Achieving fairness in distributed scheduling in wireless ad-hoc networks

Fairness is an important design criterion for medium access control protocol in multihop wireless networks. It is a complex problem due to its many dimensions that include consideration of location-dependent contention, spatial reuse of channels, and desire to achieve fully distributed scheduling in the wireless communication systems. This paper presents a localized and fully distributed algorithm with fair scheduling in multihop wireless networks. The proposed algorithm incorporates start time fair queuing (STFQ) into the distributed coordination function (DCF) in IEEE 802.11. Our algorithm accounts for the services that have already been received by the sender to adjust the backoff timer to ensure that every flow gets a fair service. We propose a simple data structure that every node (sender or receiver) needs to maintain and an update mechanism that achieves fairness. We illustrate through simulations that the proposed algorithm achieves the desired fairness.