关键词: 多指数连续相位调制, 非数据辅助, 前馈, 符号定时恢复, 联合似然函数

Abstract:

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.

Key words: Multi-h Continuous Phase Modulation (CPM), non data-aid, feedforward, symbol timing recovery, joint likelihood function