Bit Error Rate and Channel Capacity Performance of Telemetry Modulation Methods Under Typical Reentry Plasma Sheath Channel

摘要

Due to the severe impact of plasma turbulence on electromagnetic waves, the dynamic plasma sheath can degrade communication quality, even resulting in communication blackouts. This article studies the effect of different frequency bands and two typical telemetry modulation methods on communication signals under a time-varying plasma sheath channel. First, considering plasma dynamics on different scales, a typical reentry plasma sheath channel response is simulated and analyzed. Then, the average bit error rate (BER) and channel capacity of M-ary phase-shift keying (MPSK) and M-ary frequency-shift keying (MFSK) evaluating the telemetry communication performance are derived theoretically and simulated numerically based on the typical reentry plasma sheath channel response. The simulation results show that BPSK and noncoherent-MFSK (NC-MFSK) in the Ka-band and above bands have a preferable communication performance; when bit-to-noise ratio > 10 dB, BER < 10(-5) and channel capacity loss < 10(-3) for both BPSK and NC-MFSK (M >= 8) modulations in the especial reentry plasma condition (ERPC). Comparing BPSK and NC-MFSK in the Ka-band and above bands, the performances of BER and channel capacity follow the order: NC-MFSK (M >= 8) > BPSK > NC-4FSK > NC-2FSK. In particular, results indicate that under the dynamic plasma channel, terahertz communication can effectively improve communication performance and alleviate communication blackout.