트렐리스부호화 M-ary PSK 변조기법의 성능 향상을 위한 새로운 심볼 사상방법에 관한 연구

Multi-level modulation techniques permit high data rates within fixed bandwidth constraints. A convenient set of signals for M-ary PSK is φ i (t) = A cos(ω c t + θ i), 0 < t ≤ T s , where the M phase angles are θ i = 0, 2π M ,. .. , 2(M − 1)π M. For equiprobable ones and zeros the PSD for M-ary PSK is S φ (ω) = A 2 T s Sa 2 (ω − ω c) T s 2. The symbols in this case are of duration T s , so the information (or bit) rate T b satisfies T s = T b log 2 M. The potential bandwidth efficiency of M-ary PSK can be shown to be f b B = log 2 M bps/Hz. A phase diagram and signal constellation diagram for the case of M = 8 are shown below: