Phase and power estimation for per-hop multi-user detection in frequency-hopping systems

Per-hop multi-user detection (PH-MUD) is a general class of techniques for frequency-hopping systems that enable multiple interfering hops to be simultaneously demodulated. Such techniques have the potential to increase the number of supportable users and increase per-user throughput. To realize these gains in actual systems, however, channel estimation capabilities sufficient for successful PH-MUD must be developed. In fact, the fundamental feature of such systems, hopping, requires that estimation be performed on a perhop basis, which precludes training amortization. We describe potential estimation techniques for PH-MUD and evaluate the resulting overhead, energy requirements, and performance. Practical estimation techniques with reasonable overhead are seen to provide good PH-MUD performance; thus PH-MUD remains a promising capability for frequency-hopping systems.