Precoding and Successive Decoding for Throughput Enhancement in Random Access Wireless Networks

The collision avoidance paradigm which forms the basis for existing random access protocols (e.g. the IEEE 802.11 CSMA/CA with CTS/RTS) employs orthogonal multiaccess-a suboptimal strategy under most operating conditions. This paper illustrates use of precoding and successive decoding to support concurrent mutually interfering transmissions at both the multiaccess and network protocol layers to yield significant throughput benefits over a range of received interfering transmission powers. The proposed schemes include practical admission control criteria based on quality of service requirements (specified by requested minimum rates and maximum tolerable outage probability levels) and superposition coding or Costa precoding at intermediate nodes where local broadcast channels are encountered while traversing assigned multihop routes.