A Framework For Coping With Intra-Node Adjacent Channel Interference In Multi- Channel Multi-Radio Mesh Networks

Abstract

Typically, in a wireless data network, all devices use the same channel (i.e. the same frequency) so that they can easily communicate with each other. However, as node density increases, the throughput share of each device decreases due to contention of the wireless medium. It seems that the capacity problem in wireless mesh networks can be alleviated by equipping the nodes with multiple radios tuned to non-overlapping channels. In theory it should be possible to have simultaneous reliable transmissions on orthogonal non-overlapping channels. In practice though, due to signal leakage from one channel to another, transmissions on these non overlapping channels interfere with one another. In this thesis, I claim that the assumption of perfect independence between non-overlapping operating channels does not always hold in general. During this work, I have done some practical measurements about adjacent channel interference, taking into consideration various factors such as antenna separation, number of channels and radio, transmit-power and packet size. I have compared the interference effects in different channels. Furthermore, I have evaluated and studied the causes and effects of adjacent channel interference via analysis, calculations and simulation. In order to cope with this problem, a classification of possible solutions which are feasible is discussed, and then by adopting the concept of reservation, I propose a solution called MRR (Multi-Radio Reservation). Finally the proposed solution is evaluated.