CSMA and CSMA/CD with random signal powers

A throughput analysis is provided of CSMA (carrier-sense multiple-access) and CSMA/CD (CSMA with collision detection) protocols using random signal powers to induce a capture effect when the ratio of the tagged packet power to the total power of interfering packets exceeds a preset detection threshold. The pseudo-Bayesian stabilization of CSMA and CSMA/CD with random two-power levels is also discussed. It is shown that the use of random signal powers improves the throughput of CSMA and CSMA/CD, but the improvement is not as large as in slotted or unslotted Aloha. The throughput improvement is much higher with a multipower model, but the power level is too large to be practical. With random signal powers, the system can operate at a higher channel traffic and therefore has a larger stable domain, and the packet delay is reduced at the same channel traffic load.<>