Continuous‐phase modulations for CDMA radio communications: Modem architecture and performance
Filippo Giannetti, Marco Luke, R. Reggiannini · European Transactions on Telecommunications · 1996
Abstract In this paper we analyze the structure and the performance of a digital modem for band‐limited spread‐spectrum signals to be employed in a radio communication network with asynchronous code‐division multiple access and constant‐envelope continuous‐phase modulation. After a description of the modem structure and the evaluation of its bit error rate in the presence of co‐channel interference, we tackle the key point of code synchronization. In particular, we present a detailed analysis of the code acquisition strategy, assessing its performance in terms of false alarm probability, missed detection probability and mean acquisition time. Furthermore, we address the problem of code chip timing recovery, describing the performance of three different code tracking loops in terms of the steady‐state RMS chip timing error jitter. The analytical approach we present can be applied to any Continuous Phase Modulation (CPM) format that can be approximated by an Offset‐QAM signal, such as Gaussian‐filtered Minimum‐Shift Keying (GMSK).