Channelization Considerations for PSK Modulation Techniques in Follow-on UHF MILSATCOM Systems

摘要

This report develops tradeoffs and requirements on channel spacing for the follow-on FLTSAT/LEASAT UHF MILSATCOM satellite system given realistic operating conditions where high-power and low-power terminals may be located on adjacent channel frequencies. Results obtained here can be used to develop guidelines on expected system performance and/or specifications on allowable losses due to adjacent channel interference and inband channel filtering losses. This report presents the results of MILSATCOM UHF 5-kHz and 25-Khz nonlinear (hardlimited) channel performance as a function of modulation type and symbol rate, filter characteristics (type), and adjacent channel spacing. The primary channel performance measure is transmitted bit energy per channel noise (E/N) versus probability of bit error. Filter bandwith is expressed as a BT product, where B is the two-sided 3-dB bandwidth and T is the symbol rate. In general, for most simulated configurations, the system is insensitive to filter type and Adjacent Channel Interference. ACI has an impact only under conditions of narrow channel spacing (e.g., 5 kHz for 5-kHz channels and 50 kHz for 25-kHz channels) and high adjacent channel interference power.