| Because Continuous phase modulation(CPM) is a kind of phase continuous,constant envelope modulation method and has higher power efficiency and spectrum characteristics,it can be applied to a cheap and effective nonlinear amplifier and widely used in deep space communications,remote sensing,ranging,in the field of mobile communications and radio communications, and many other communication.The synchronization issues of receiver is very important for CPM transmission system, the stand or fall of synchronization performance directly affects the bit error rate performance. It is very important for CPM burst transmission system to estimated frame signal starting position and frequency offset.In this paper, the main work and innovation points as follows:(1)A best synchronization sequence is put forward and make the Cramer-Rao Bound(CRB) of synchronize related parameters minimum value. It is discussed about the timing synchronization, carrier phase and frequency offset joint-estimation CRB of CPM signal over AWGN channels, and it can get the same optimal synchronization sequence that allows the three parameters of the CRB to obtain the minimum value through the analysis of timing synchronization and frequency deviation and carrier phase CRB expression. Additionally, to compare the performance differences of the best training sequence with a random sequence for the symbol timing estimation of CPM signals. The results showed that the CPM scheme of non-binary and/or partial response have a significant gain about mean square error(MSE) of the optimal synchronization sequence.(2)Based on the best synchronization sequences of(1) and the maximum likelihood criterion, a complete synchronization algorithm of CPM burst-mode transmission is put forward. The synchronization algorithm can jointly estimate the frame signal starting position and size of the deviation, The synchronization algorithm can estimate the frequency offset through searching a dimensional network,and can estimated timing synchronization through simple closed-loop expressions.Matlab simulation shows that the MSE of synchronization algorithm is very close to the theoretical value of CRB at low signal to noise ratio, even 0dB.The synchronization algorithm can detect arrival of the frame signal, and the starting position of the frame signal accurate arrival.With thetraditional methods about barker code by MSK modulation and m sequence by BPSK modulation as synchronous sequence, the synchronization algorithm overcomes the traditional methods that are poor about the deviation in the frame synchronization performance and frequency offset estimation,and so on.(3)In this paper, the synchronization algorithm of the CPM burst-mode transmission is proposed to convert the code and implementation on CCS, and the qualitative analysis of the CCS implementation and matlab simulation results show that synchronization algorithm implementation is feasible in the range of allowable error. |
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