On Iterative EM-Based Frequency Domain Joint Estimation of Synchronization Parameter and Channel Impulse Response

In this paper, an iterative EM-based frequency domain joint estimation algorithm of synchronization parameter and channel impulse response (CIR) in direct sequence code division multiple access (DS-CDMA) system is proposed. This algorithm is based on the expectation-maximization (EM) method. A complete Cramer-Rao lower bound (CRLB) analysis of the proposed algorithms is also given in this paper. Because this algorithm can provide accurate estimation of channel conditions and synchronization parameter for DS-CDMA receivers, even with a simple equalization module, for example, a one-tap multiplier based frequency domain equalizer (FDE), good performance can be achieved at a low cost.