Combined URN and TDMA scheme for multiple-access protocols

Local area networks provide communications facilities for high-speed data transfer between computers and erminals within a limited geographical district. The investigation of methods of improving the throughput-delay behaviour of such systems, even under heavy traffic conditions, is an open and challenging research area. A new family of hybrid multiple-access protocols is proposed for contention resolution in local networks. These protocols are a combination of random and deterministic multiple-access protocols. A dynamic frame construction is used. The frame consists of a status slot, followed by an RTDMA period and a URN period. This scheme provides stability under any circumstances and allows for control mechanisms so that good throughput-delay characteristics can be achieved. Analysis shows that the proposed protocols behave better than the isolated URN or RTDMA schemes, exhibiting low access time under normal traffic, while under heavy traffic, channel utilization remains high and the delay at acceptable levels.