一种基于相位轨迹相关的GMSK突发同步设计

Burst Synchronization Design based on Phase Trajectory Correlation Algorithm

GMSK一般采用非相干解调,但是性能相对相干解调较差。最大似然解调和相干解调相近,但需要专门的定时同步算法。基于前导码的相位轨迹相关可以提供良好的同步性能,设计的算法不同于传统同步算法设计,相位轨迹的相关运算在IQ正交信号域实现,运用于最大似然解调。相比非相干解调,它可以提高接收门限;相比一般相干解调,它不要求载波同步,实现简单。它基于FPGA实现,运算架构简单,同步稳定可靠,为最大似然解调性能的发挥提供了保障基础。

The performance of using non-coherent demodulation to demodulate GMSK is not as good as relatively coherent demodulation. Maximum likelihood demodulation could provide similar performance with relatively coherent demodulation, but requires special timing synchronization algorithm. Algorithm in this paper, the design of the phase trajectory based on the preamble of the correlation can be provide good synchronization performance, different from traditional synchronization algorithm design, and phase trajectory correlation arithmetic is implemented in the IQ signal domain, used in maximum likelihood demodulation. Compared with non-coherent demodulation, the receiver could improve the receiving threshold, and compared with the general coherent demodulation, does not require the carrier synchronization. The algorithm is implemented on FPGA platform, with simple operation structure, stable and reliable synchronization, and it also could provide guarantee for maximum likelihood demodulation performance.