Timing jitter sensitivity comparison of narrowband M-PSK and bandlimited DS/SS M-PSK signals

The authors present a simple approximate expression for the bit-error-rate (BER) degradation, caused by random timing errors, of the maximum-likelihood receiver operating on narrow-band (one-sided bandwidth not exceeding the symbol rate) M-ary phase shift keying (M-PSK) and band-limited (one-sided bandwidth not exceeding the chip rate) direct-sequence/spread-spectrum (DS/SS) M-PSK signals. This expression is very accurate for (small) degradations of practical interest, and reveals that the BER degradation (in dB) is essentially proportional to the tracking error variance. It is shown that band-limited DS/SS M-PSK is considerably less sensitive to timing errors than narrow-band M-PSK, especially for large values of M and small values of the rolloff