A Spatiotemporal Contention Resolution for Enhancing Spatial Reuse in Wireless Networks

摘要

In a multihop wireless network, it is important to control access to the channel so that concurrent transmissions do not interfere with each other. Access may effectively be controlled by properly tuning protocol parameters, e.g., the contention window $CW$ and the carrier sensing threshold $CS_{th}$. Although the former parameter aims to separate, in time, different transmissions, the latter parameter reduces interference by allowing senders separated by a safe margin to engage in concurrent transmissions. We propose a localized spatiotemporal algorithm that jointly controls the selection of these parameters to enhance the spatial reuse and optimize the overall network throughput. To efficiently decide which protocol parameter(s) to tune, we deem it necessary to first distinguish between the causes of frame loss. We propose an effective loss differentiation and establish accordingly appropriate reactive methods. We consider a realistic wireless network with fading channel conditions, where time-varying channel gains cause random frame losses that need to be distinguished from losses due to collisions and strong interference. Our protocol is extended with an adaptive request-to-send probe method to consider such dynamics, and significant performance gains are observed under different fading scenarios.