On the Impact of Beamforming on Interference in Wireless Mesh Networks

For a wireless mesh network with randomly placed devices, we analyze the impact of beamforming on the statistics of the signal attenuation, interference, and SIR between devices. We show that simple random direction beamforming performs equally well as omni-directional transmission if no MAC layer is present. Optimized beamforming between transmitter-receiver pairs yields a much better SIR than omni-directional antennas. If devices are able to eliminate the strongest interferers, either using a MAC protocol or null steering, both beamforming approaches perform much better than omni-directional transmission, i.e., they allow for a given SIR threshold more concurrent transmissions in the network. In fact, applying null steering has the potential to significantly reduce the requirements for the MAC protocol in terms of blocking interferers.