Behind-the-scenes of IEEE 802.11a based multi-radio mesh networks: a measurement driven evaluation of inter-channel interference

To successfully develop IEEE 802.11a based wireless mesh network solutions that can achieve the reliability and capacities required to offer high quality triple play services the use of multiple radios in each mesh node is essential. Unfortunately, the co-location of multiple antennas in a single device leads to a number of interference problems. In this paper the impact of non-overlapping channel interference in IEEE 802.11a based multi-radio nodes is investigated. A detailed explanation of the performance decreases and their relation to radio settings is presented. The primary contribution of this paper is the discovery of a channel interference effect which is present over the entire 802.11a frequency space. This interference appears if two radios are located less than 50 cm from each other and both are attempting to operate as usual. The results were obtained by conducting experiments in a well planned testbed to produce reliable and reproducible results. The presented results incorporate multiple parameters including transmission power, modulation coding scheme, channel separation and physical layer effects such as adjacent channel interference, carrier sensing, retransmissions and packet distortion.European Community's Seventh Framework ProgramPublicad