Research On The Performance Of Coded Continuous Phase Modulation Systems

With the rapid development of wireless communication technology, various communication systems have emerged, which makes the resource of wireless spectrum increasingly strained. Meanwhile, the requirement of wireless communication systems is continually improved by people, and people hope that the systems should have many advantages, for example high transmission rate, robustness to burst errors, high efficient power and bandwidth efficiency. The systems of deep space communication, satellite communication and mobile communication have the characters of far communication distance and large energy attenuation, and how to save signal power and improve bandwidth efficiency become an important problem. The combination of advanced channel coding and efficient modulation is an effective way to solve this problem.Convolutional code (CC) that makes full use of the correlation among code words is a channel coding with excellent performance. The code has been widely used in wireless communication standards, such as GSM, CDMA2000, IS-95, and has played an important role in Satellite communications, deep space communications and mobile communication because of its advantages, such as strong error detecting ability, small coding delay and low implementation complexity. Continuous phase modulation (CPM) is a method for modulation of data commonly used in wireless modems. It is used primarily because continuous phase modulation has good spectral efficiency for a noncoherent modulation technique. Furthermore, CPM is typically implemented as a constant-envelope waveform, i.e. the transmitted carrier power is constant. Therefore, CPM is attractive because the phase continuity yields high spectral efficiency, and the constant-envelope yields excellent power efficiency. CPM has a lot of realization ways, such as MSK and CPFSK.The paper mainly discusses the combination of convolutional code and CPM for wireless communications applications, and the performance of CC-MSK system, CC-CPFSK system and SCCPM system is studied. In order to solve the problem of information sharing between demodulator and decoder in traditional receiver of SCCPM system, an iterative detection method based on SISO algorithm is proposed. Then the effect of main parameters on the performance of the system is studied, which can provide the reference basis for practical application.