HIGH CAPACITY ASYNCHRONOUS RANDOM ACCESS USING TIME-OF-ARRIVAL BASED COLLISION RESOLUTION.

High-capacity random-access protocols for unslotted channels with arbitrary propagation delay are proposed and analyzed. The protocols described are based on the fact that analysis of observed asynchronous collisions enables terminals to extract partial time-of-arrival information, by the use of which highly efficient collision resolution procedures can be executed. Specifically, asynchronous collision burst analysis makes it possible to mutually order a subset (the size of which depends on the channel feedback available) of the interfering packets. The resolved (ordered) packets can then be retransmitted without further conflict in a scheduled (FCFS) manner. It is demonstrated that for the simplest channel feedback (continuous signal detection), a capacity of 0. 41 is achieved, increasing to 0. 509 when continuous collision detection capability is added. A modified form of collision detection which is simply implemented even on RF channels is shown to provide a capacity as high as 0. 47.