A fairer multiple access protocol for multi-hop wireless networks: hybrid asynchronous time division multiple access protocol (HATDMA)

In this paper, we investigate fairness properties of MAC protocols in multi-hop ad-hoc networks that have identical ranges of communication, interference and carrier sensing. We propose a new MAC protocol-hybrid asynchronous time division multiple access (HATDMA). The proposed protocol contains two schemes: SI-RI hybrid scheme and ATDMA scheme. The hybrid scheme employs both sender-initiated (SI) and receiver-initiated (RI) collision avoidance mechanisms and adoptively chooses one of them to use based on the observed performance. The ATDMA scheme requires a flow just getting a successful transmission to suspend the next transmission for a period of time that is derived from the traffic load observed around the flow. Comprehensive simulations show that HATDMA can yield high aggregate throughput and at the same time achieve very good fairness.

1. Introducton

One of the key elements in the design of single channel wireless ad hoc networks is the medium access control (MAC) protocol with which nodes share a common channel. Due to the distributed nature of ad-hoc networks and the lack of a central control entity, distributed random access MAC protocols are preferred to the centralized MAC protocols [1].