Medium access control with channel state information for large sensor networks

Abstract

Traditionally, random access protocols have been designed and studied by assuming simple models for the physical layer. We introduce a reception model that incorporates the channel states of the transmitting users and allows for multiple simultaneous successes. We assume that each user has access to his channel state and propose a variant of the Slotted ALOHA protocol for medium access where the transmit probability is chosen as a function of the channel state. We introduce the notion of asymptotic stable throughput and characterize the achievable asymptotic stable throughput through the use of channel state information. As an example, we consider the application of the results to sensor networks.