Exploiting an Optimal Delay-Collision Tradeoff in CSMA-Based High-Dense Wireless Systems

A novel carrier sense multiple access strategy with collision avoidance (CSMA/CA) balancing contention probability and channel access time is proposed. The approach can be applied to any context where the computational simplicity of the MAC must be preferred to the complexity of the channel access strategy. Our MAC, called Delay-Collision CSMA (DC-CSMA), is a slotted nonpersistent CSMA/CA with nonuniform contention probability distribution, designed to reduce at the same time latency of contenders and preserve a high successful access probability. An utility function aiming at equalizing the effects of these two performance metrics is introduced, and the related theoretical properties and optimal distribution are derived. DC-CSMA is insensitive to the number of contenders and very robust with respect to contention window size, packet length, and impairments such as frame synchronization errors and hidden terminals, and it does not require any adaptive tuning to optimize its performance. Current technologies such as WSN, RFID, IoT devices can benefit from such a simple access technique. The numerical evaluation has been led out considering latency, successful probability and throughput, and DC-CSMA has been compared with other classical strategies such as CSMA with uniformly distributed contention probability, CSMA/ p∗ and Sift distribution.