Spatial reuse in wireless ad-hoc networks

Abstract

When investigating co-channel spatial reuse, typical studies on ad-hoc networks have adopted static, device-specific transmission/interference ranges regardless of the runtime environment. In this paper, we present an analytical framework to investigate co-channel spatial reuse in dense wireless ad-hoc networks based on RF propagation models for some common network topologies. We derive the minimum separation between simultaneous co-channel transmitters while maintaining desirable signal-noise-interference-ratio at receivers. Spatial reuse is characterized by the ratio between co-channel transmitter (T-T) and transmit-receiver (T-R) distances. Our results show that increasing transmission power improves spatial reuse in ambient noise dominated environments. However, in co-channel interference limited scenarios, increasing transmission power has little effect on spatial reuse. On the other hand, more simultaneous transmissions can be physically possible by decreasing the average T-R separation, independent of transmission power. Our results confirm that the popular practice of using static transmission/interference ranges leads to an oversimplified model that is unable to accurately characterize the spatial reuse (and consequently aggregate network capacity) in ad-hoc networks.