Non-Coherent Phase Compensated Sphere Detector for Partial Response CPM

Continuous phase modulation (CPM) has been widely used in wireless communications, as its continuous phase and constant envelop lead to high bandwidth and power efficiency. Non-coherent detection of CPM is promising in real applications, as carrier phase recovery is not necessary. However, there is a performance gap between the non-coherent and coherent detections, especially for partial response CPM. In this letter, a non-coherent phase-compensated sphere detector (PC-SD) is proposed. Under a same observation length, the proposed non-coherent PC-SD significantly outperforms the conventional non-coherent maximum-likelihood detector for partial response CPM, with a much lower computational complexity. Furthermore, the proposed non-coherent PC-SD also outperforms the state-of-the-art delay-optimized differential detector, and reduces the gap between non-coherent and coherent detectors to only 1 dB. Finally, the proposed non-coherent PC-SD is very robust against Doppler shift.