I/Q imbalance compensation and channel equalization algorithm for MISO-OFDM systems

Abstract

In this paper, both the I/Q imbalance compensation and the channel equalization algorithm are proposed for space-time-block-code (STBC) MISO-OFDM systems. The I/Q imbalance compensation scheme is composed of self-calibration and tracking processes. The self-calibration process is further divided into two stages, symmetric- and anti-symmetric-tone, employed to extract the gain and the phase mismatches of transmitter (Tx) and receiver (Rx) I/Q imbalance for end-user in system power-on. According to the results of self-calibration process, both pre-and post-compensation block is presented to eliminate the Tx and Rx I/Q imbalances of end-user, respectively. In addition, the remote Tx I/Q imbalance compensation can be merged into the channel equalization process, based on MMSE criterion, on each subchannel.