In this letter, a compact CORDIC algorithm is proposed to efficiently implement a synchronization block for carrier frequency offset (CFO) in OFDM modems. The compact CORDIC algorithm allows us to combine a CFO estimation block and a CFO compensation block into a single CFO synchronization block. It is shown by FPGA implementation results that the compact CORDIC algorithm can achieve a significant reduction in hardware complexity and latency for implementing the synchronization block in OFDM modems.

In this letter, we propose a new preamble structure for channel estimation in a MIMO OFDM-based WLAN system. Both backward compatibility with IEEE 802.11a and low overhead are considered in designing the preamble. Simulation results show that the proposed preamble has low overhead and good performance gain for channel estimation.