Study of Acknowledgment Schemes in a Star Multiaccess Network

In distributed random access communication, collision occurs when two or more transmissions overlap in time. After a transmission a user should know whether his attempt was successful so that he can decide his next action. Acknowledgments are commonly used to indicate whether a transmission is successful. The authors study the effect of acknowledgments on the performance of a star broadcast network. They evaluate the network performance for the following four cases: free and instantaneous acknowledgment, common channel for data and acknowledgments, split channel for data and acknowledgments, and a common channel with high-power acknowledgments. The study reveals that the split channel has the highest capacity, and that the high-power scheme provides an attractive economical alternative when data packets are short.