Research On The Key Techniques Of The Receiver In The Continuous Phase Modulation System

The continuous phase modulation(CPM) signal has continuous phase and constant envelope which result in compact spectrum and high efficiency of spectrum usage. In these systems, the high efficient and low cost nonlinear power amplifiers can be used to reduce the cost and equipment’s power consumption. Meanwhile, the continuous phase modulation is a kind of nonlinear modulation, as the modulation process can be equivalent to the concatenation of an encoder and a linear modulator, we can use iterative detection to CPM signal by combining the channel coding techniques. Low complexity frequency domain equalization is a common used method to reduce the inter symbol interference(ISI) over multipath fading channel, but this kind of system has a poor performance as the discrete channel impulse response is varying over the multipath time varying channel. So this article focuses on the study of iterative equalization technique for CPM signal in time varying channel.We first discuss the background and significance of this topic, elaborate the research status of continuous phase modulation and constant envelope orthogonal frequency division multiplexing(CE-OFDM), then give a brief summary of the main content and the arrangement.In chapter two we study the CPM signal adaptive equalization algorithm which based on per-survive processing(PSP) in time varying channel, and then present an adaptive tracking algorithm which is suitable for fast time varying channel. We first introduce the modulation theory,the phase status and the channel model of the CPM signal. Then we study the equalization algorithm which based on adaptive per-survive processing technique, and compare the performance with the traditional time domain equalization algorithm.In chapter three we mainly study the adaptive iterative detection(AID) algorithm for CPM signal in time varying channel. We first study the adaptive per-survive processing soft demodulation algorithm, then realize the adaptive iterative detection for CPM signal, and study the performance in the single path time varying channel and the multipath time varying channel. As the soft demodulation complexity increase when the path number increase, we also study a low complexity soft demodulation algorithm and present the complexity analysis and simulation results.In chapter four we study the demodulation algorithm and the performance of CE-OFDM technique in millimeter wave channel. We first introduce the modulation and demodulation theory of CE-OFDM, then present the demodulation performance of the receiver in CE-OFDM system over AWGN channel. Finally, we present the performance analysis of CE-OFDM in multipath channel and 802.11 ad channel.In chapter five we summarize the main contributions of this article, and give a general description of the problems of these two constant envelope modulation. Finally, we give some suggestions for further research.