Simulation of a Narrow Bandpass-Limited Satellite Channel
MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB
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The effects of a bandpass-limiting satellite channel, such as a B25- kHz hard-limiting FLEETSAT channel, on several modulation techniques were simulated. The modulations included BPSK and various forms of QPSK, including offset QPSK and continuous-phase minimum frequency shift keying MSK. Coherent matched-filter receivers and both uplink and downlink noise were assumed. For a bit error probability of 0.005 and a SNR loss of less than 1 dB caused by the nonlinearity in the FLEETSAT case, the maximum standard data rate R was 19.2 kbps for BPSK but 32 kbps for offset QPSK, MSK and QPSK. Rates of 24 kbps for BPSK and 48 kbps for offset QPSK and MSK were attainable at this same reliability with a SNR degradation of about 4 dB and 2.5 dB, respectively. Larger degradations are expected at lower error rates.
- Non-Radio Communications