DCTPSK:AN EFFICIENT MODULATION TECHNIQUE FOR DIFFERENTIAL DETECTION

摘要

We introduce a modem which considers the modulator jointly with differential detection and uses spectral shaping techniques to achieve bandwidth and power efficiency in nonlinear channels.This new technique is called Differentially-detected Controlled Transition PSK (DCTPSK).The baseband waveshapes,eye diagrams and signal space diagram of DCTPSK are given.Its bit error rate performance for differential detection is calculated and its power spectral density is obtained.In linear and nonlinear channels,the compact spectrum of DCTPSK enables it to utilize the available bandwidth more efficiently than wellknown modulation techniques such as DQPSK and DMSK.In a hardlimited channel,the bit error rate performance of DCTPSK is comparable to those of DQPSK and DMSK.To our knowledge,this is the only quadrature modulation technique that constructs the signals particularly for differential detection and also constrains the spectral regrowth after a nonlinearity without using a delay element.