Matched Filter Mismatch Losses in MPSK and MQAM Using Semi-Analytic BEP Modeling

The focus of this paper is the bit error probability (BEP) performance degradation when the transmit and receive pulse shaping filters are mismatched. The modulation schemes considered are MPSK and MQAM. In the additive white Gaussian noise (AWGN) channel both spectral efficiency and noise mitigation is commonly achieved by using square-root raised cosine (SRC) pulse shaping at both the transmitter and receiver. The novelty of this paper primarily lies in the use semi-analytic BEP simulation for conditional error probability calculations, with transmit and receive filter mismatch, the optional inclusion of a small FIR equalizer. For lower order MPSK and MQAM, i.e., 8PSK and 16QAM power degradation at is 0.1 dB when the excess bandwidth mismatch tx/rx = 0.25/0.35 or 0.35/0.25, but quickly grows as the modulation order increases and/or the mismatch increases.