MUD Enabled Media Access Control for High Capacity, Low-Latency Spread Spectrum Communications

Unlike conventional wireless communication systems that operate under an interference avoidance paradigm, the DARPA Interference Division Multiple Access (IDMA) program exploits multi-access interference to enable high-capacity, low-latency spread spectrum communication that requires no infrastructure or coordination. The enabling technology behind IDMA is Multi-User Detection (MUD) at the Physical Layer, which enables a receiver to simultaneously demodulate multiple interfering users. To fully exploit this new Physical Layer capability, novel Media Access Control (MAC) protocols are required that control and encourage users to collide rather than avoid interference all together. This paper discusses the motivating factors behind the IDMA MAC design and highlights the technical challenges in developing a MAC that both facilitates and exploits MUD at the Physical Layer. Particular attention is given to key decentralized MAC mechanisms, including distributed synchronization and scheduling. Analysis is presented highlighting the performance gains of IDMA over conventional adhoc communication systems, such as 802.11. Looking to the future, insight is provided into military applications and concepts of operations where IDMA technology is expected to dramatically improve performance and provide novel capabilities to the warfighter.