Cooperative Transmission for Random Access Wireless Networks

Abstract

We propose a novel high-throughput medium access scheme for wireless networks that is suitable for bursty sources. We view the wireless network as a spatially distributed antenna, with antenna elements linked via the wireless channel. When there is a collision, the packets involved in the collision are saved in a buffer. In the slots following the collision, a set of nodes, designated as relays, form an alliance and bounce off the signal that they received during the collision slot. By processing the originally collided packets and the signals forwarded by the relays, the destination node can formulate and solve a multiple-input multiple-output problem, the inputs of which are the original packets. The spatial diversity introduced via the cooperative relaying enables us to deal with the wireless channel effectively without any bandwidth expansion nor additional antenna hardware. The proposed scheme maintains the benefits of ALOHA systems in the sense that all nodes share access to media resources efficiently and without extra scheduling overhead, and enables efficient use of network power.