BER performance of anti-multipath modulation PSK-VP and its optimum phase-waveform

A novel antimultipath modulation method, called PSK-VP (phase shift keying with varied phase), in which a varied phase-waveform is redundantly imposed on the DPSK timeslot is proposed. The optimum phase-waveform is discussed by using an approximate analysis based on a special diversity with a continuous branch. A formula-type bit error rate (BER) expression is obtained by the analysis and shows the optimum phase-waveform condition. A convex phase-waveform asymptotically satisfies the optimum condition as its phase shift peak is increased. PSK-VP with a convex phase-waveform extends the delay difference upper limit to almost one symbol and shows an excellent BER for multipath fading with delay differences less than the upper limit. A strict numerical calculation also confirms the results and shows that 4-ary PSK-VP can nearly double the upper limit as measured in bits, which is about 1.7 bits for the convex phase-waveform