基于连续相位调制的OFDM信号研究

采用连续相位调制技术中相位转移平滑、频带利用率较高和带外功率较低的特性,研究了连续相位调制信号与部分响应序列相结合的方法,解决了OFDM信号峰平功率比较大的问题。建立了系统的数字模型并进行了仿真,仿真结果验证了该方法可以明显降低OFDM信号峰平功率比。

Reducing PAPR (Peak-to-Average-Power Ratio) in OFDM (Orthogonal Frequency Division Multiplexing) Signal Transmission

Aim.To our knowledge,there is no paper in the open literature dealing with how to reduce PAPR.We now propose a method that can do it.CPM(continuous phase modulation) offers higher channel utilization and requires lower baseband power because of its smooth phase transfer characteristics.In the full paper,we explain in some detail our new method and the analysis of its simulation results;in this abstract,we just add some pertinent remarks to listing the two topics of explanation.The first topic is: OFDM-CPM transmission system.In this topic,we establish a mathematical model for the OFDM transmission system.Then,also in the first topic,we analyze the multi-amplitude CPM using double-value CPM constellation to illustrate how to reduce PAPR value.Still in the first topic,we study how to combine the multi-amplitude CPM with PTS(partial transmit sequence) algorithm.The algorithm uses various sequences to do weighted calculation of OFDM signals and transmit only those of smaller PAPR value.The second tropic is: simulation results and their analysis.In this topic,we simulate the algorithm that uses the modulation indices of 1/2 and 2/3 respectively.The simulation results,given in Fig.3 and Fig.4 in the full paper,show preliminarily that,when the multi-amplitude CPM signals combined with PTS are used,the PAPR value of OFDM-CPM transmission system is much smaller than that of the system which does not use the algorithm,and more importantly,the algorithm does not magnify the complexity of the system implementation.