Analysis of a MUD-based Situation Awareness Messaging System without a Feedback Channel

This paper is concerned with enhancing situation awareness messaging using multi-user detection (MUD) techniques. Situation awareness messaging involves sending short packets of situation update data. Low latency is an important requirement. This paper focuses on using satellite communications which have a substantial propagation delay. Random access systems without channel feedback information are particularly preferable for such situations. However, the main draw back of these systems is their low channel utilisation. In this paper, the capacity of a MUD-based random access system without a feedback channel is analysed. The results obtained showed substantial improvements when the system is employed with multi-user detectors. A large spread of received packet powers is typically expected in wide area mobile applications. In many implementations, a spread of powers inhibits receiver performance however when MUD is employed it becomes an enhancing factor.