MSK performance under various fading conditions in the presence of worst-case CW interference

The author analyzes the flat-fading-channel performance of coherent MSK (minimum shift keying) matched filter demodulation in the presence of cochannel interference. It is shown that the most deleterious interference is CW (continuous wave) at center frequency. Bit error rate (BER) performance is first characterized for nonfading signal and interference typical of a terrestrial line-of-sight scenario. Subsequent analyses address fading signal vs. nonfading interference (typical of a long skywave or scintillation communication path and local interference), fading signal vs. fading interference (typical of satellite communication performance in ionospheric fading and remote interference), and nonfading signal vs. fading interference. The performance under fading-signal conditions, regardless of whether the interference is constant (short range) or fading (long range), is extremely poor; to be usable, such channels will require the use of diversity techniques