This paper describes a CSMA channel access algorithm that is capable of detecting collisions in radio channels. Radio networks have a special problem in that the transmitted and received signal amplitudes differ by orders of magnitude. This makes it infeasible to detect collisions by comparing the transmitted and received signals. The algorithm in this paper is based on the sender pausing briefly during transmission and listening to the channel. If the channel is not idle during the pause, a collision has occurred.

The author evaluates the throughput, channel capacity, and throughput-delay performance of the algorithm. The paper also discusses the dependence of performance on the duration of the collision detection interval, the minimum transmission duration following detection of a collision that guarantees that the collision will be sensed by all receivers. The author concludes that this algorithm exhibits improved performance relative to standard CSMA, especially under high loads and near the limit of channel capacity.