The MIMO OFDM receiver with mismatched transmit carrier frequency offsets

Abstract

The combination of multiple-input multiple-output (MIMO) and orthogonal frequency division multiplexing (OFDM) has been adopted as the next-generation wireless LAN technology. In this paper, we consider the design of a 2×2 space-time block coded (STBC) MIMO-OFDM baseband receiver with different carrier frequency offsets between transmit antennas due to an antenna resistance match problem. We propose a new carrier frequency offset tracking algorithm to estimate the mismatch of carrier frequency offsets between two transmit antennas. As the carrier frequency mismatch is corrected at transmitters via the side information channel, the performance of the MIMO OFDM receiver can approach the result without carrier frequency offsets. The overall receiver is also designed on the Xilinx FPGA with an implementation loss of about 1.5 dB.