Providing Transmission Security for Contention-based Multiple Access

Transmission Security for many satellite communications systems involves encryption and also techniques to deny an adversary traffic flow analysis capability. A known approach for providing traffic flow security in reservation-based multiple access systems involves the use of "dummy" bursts to fill in any gaps in the actual traffic flow. However, in contention-based systems this approach would unnecessarily limit user capacity in the channel. In this paper we present a technique that provides traffic flow security without a significant reduction in overall user network capacity. We describe how this technique can be applied to many different satellite network systems, and also to terrestrial ad-hoc radio networks that use contention-based access.