多指数连续相位调制信号非数据辅助的前馈符号定时恢复算法

针对多指数连续相位调制(Multi-h CPM)信号的符号定时恢复困难且算法复杂的问题，提出了一种多指数(Multi-h) CPM信号的非数据辅助的前馈符号定时恢复算法。该算法基于Multi-h CPM信号的调制指数同步偏差和符号定时偏差的联合似然函数，通过平均可能的调制指数同步偏差所对应的期望函数将其联合似然简化，得到符号定时偏差似然函数以及符号定时偏差估计值，并给出了其定时偏差估计算法的修正的Cramer-Rao限(MCRB)以及其符号定时恢复的实现方案。仿真结果表明，该算法适用于全响应和部分响应的Multi-h CPM信号，符号定时恢复性能良好且对残留载波频偏和调制指数同步偏差不敏感。

Non Data-aided Feedforward Symbol Timing Recovery for Multi-h CPM

To solve the difficulty and complexity of symbol timing problem of Multi-h CPM (Continuous Phase Modulation), a non-data-aided feedforward symbol timing recovery algorithm for multi-h CPM was proposed. The joint likelihood functions of modulation index offset and symbol timing offset were simplified into the likelihood functions of symbol timing offset and estimation of symbol timing offset was acquired by means of averaging the expectation functions according to possible modulation index offset. Modified Cramer-Rao Bound (MCRB) and implementation scheme of the proposed symbol timing recovery were presented. The simulation analyses show that, the proposed algorithm is suitable for full response and partial response multi-h CPM. Meanwhile, symbol timing recovery performance is good, and is not sensitive to the carrier frequency offset and modulation index offset.