Performance of Phase Comparison Sinusoidal Frequency Shift Keying

Some communication systems require the close packing of many signals into a fixed bandwidth while precluding an absolute phase reference at the receiver and time synchronization between the signals. This paper investigates the bit error performance in the presence of white Gaussian noise of PCSFSK, which has been found to be very bandwidth efficient under the above conditions; much more efficient than DQPSK. PCSFSK is found to perform slightly better than an upper bound on the performance of DQPSK for high signal-signal-to-noise ratios and somewhat worse for low signal-to-noise ratios, while allowing much closer packing of unsynchronized signals.