The Myth of Spatial Reuse With Directional Antennas in Indoor Wireless Networks
Interference among co-channel users is a fundamental problem in wireless networks, which prevents nearby links from operating concurrently. Directional antennas allow the radiation patterns of wireless transmitters to be shaped to form directed beams. Conventionally, such beams are assumed to improve the spatial reuse (i.e. concurrency) in indoor wireless networks. In this paper, the authors use experiments in an indoor office setting of Wifi Access points equipped with directional antennas, to study their potential for interference mitigation and spatial reuse. In contrast, to conventional wisdom, they observe that the interference mitigation benefits of directional antennas are minimal. On analyzing the experimental traces they observe that directional links do not reduce interference to nearby links due to the lack of signal confinement due to indoor multi-path fading.