The tone sense multiaccess protocol with partial collision detection (TSMA/PCD) for packet satellite communication

The (TSMA/PCD) contention protocol is designed for packet satellite communications. This protocol is particularly suitable for a satellite system serving an area with a dense population of Earth stations. By incorporating a narrowband ground radio channel for broadcasting busy tones, the Earth stations are able to avoid packet collisions by sensing the absence of busy tones before transmitting packets, and partial collision detection capability can also be achieved. The performance of TSMA/PCD is found to be somewhere between CSMA (carrier-sense multiaccess) and CSMA/CD, depending on the number N of busy tones used. When N=50, single-tone TSMA/PCD gives almost identical performance as CSMA/CD, while for multitone and slot-by-slot announcement TSMA/PCD protocols, only N=8 and N=2, respectively, are sufficient to drive the system to the CSMA/CD performance. Both nonpersistent and 1-persistent TSMA/PCD give lower delays than their corresponding CSMA protocols. The performance of the protocols in a noisy satellite channel is also studied.<>