Throughput Enhancement of Random Access in Unstructured Networks via Successive Decoding

Existing random access protocols are essentially based on the collision avoidance paradigm (e.g. the IEEE 802.11 CSMA/CD with CTS/RTS) which corresponds to orthogonal multiple access. This is known to be optimal, in the information-theoretic sense, only in slowly fading communication channels that are in deep-fade states; further, in such propagation environments, the achievable rates are negligible. At higher operating powers, theoretical upper bounds on the achievable rates of interference channels motivate the admission of concurrent transmissions to be supported by successive decoding techniques. Practical admission control criteria based on quality of service requirements specified by requested minimum rates and maximum tolerable outage probability levels are proposed and the resulting successive decoding protocols are shown to yield several-fold improvements in throughput over a range of interfering transmission powers.