ALOHA-NUI: A collision-free version of ALOHA using a Neighborhood-Understood Index

Abstract

ALOHA with priority acknowledgments (ACK) is transformed into a collision-free channel access method by means of a neighborhood-understood index (NUI). Each node maintains the NUI, which allows nodes to remember all nodes that requested to share the channel and the order in which they should be allowed to transmit. The resulting protocol, ALOHA-NUI, adds signaling packets and NUI information in data packets to maintain the NUI, rather than just remembering that a data packet was sent successfully as in ALOHA. This results in ALOHA-NUI, which is compared with TDMA assuming a fixed transmission schedule, ALOHA with priority ACK’s, and CSMA with priority ACK’s analytically and by simulation. ALOHA-NUI is shown to attain the high throughput of collision-free transmission scheduling methods that usually require clock synchronization while maintaining most of the simplicity of ALOHA with priority ACK’s. ALOHA-NUI is also shown to be fair and to reach stable transmission schedules very quickly.