Joint Carrier Synchronization and Equalization Algorithm for OFDM Systems - Loop-Delay Analysis and Complexity Consideration

In this paper, the loop-delay analysis and the com- plexity consideration of the joint carrier synchronization and equalization algorithm for OFDM systems are presented. As a result, the loop-delay induces an additional phase lag and further gives rise to instability for the dual-loop carrier synchronization loop. In addition, the complexity consideration shows that the presented algorithm definitely accomplishes the cost-effective feature compared with the previous works. I. INTRODUCTION OFDM system is very sensitive to the carrier frequency offset (CFO), which induces the intercarrier interference (ICI) and thus degrades the system performance. The joint carrier synchronization and equalization algorithm (1) is presented to combat the residual CFO and the channel equalization concurrently for OFDM systems in the tracking stage over the multipath fading channel. The cost function of the joint algorithm is derived to minimize the error power on each subchannel based on the minimum mean square error (MMSE) criterion. Therefore, the cost function J(·) on each subchannel can be expressed as