Analysis and suppression of phase noise and IQ imbalance for dual-band MIMO-OFDM

Carrier aggregation (CA) schemes and multiple antenna techniques are used for the orthogonal frequency division multiplexing (OFDM) in order to highly improve the communication capacity in LTE-advanced. In order to implement the multi-band system based on multiple-input multiple-output (MIMO) technique, a wideband frequency synthesizer is required. But, when using broadband frequency synthesizer, serious phase noise problem occurs at the transceiver. In addition, when using MIMO scheme, IQ imbalance is a critical impairment as it causes inter carrier interferences (ICI), that results in severe degradation of the receive performance. Therefore, a joint phase noise and IQ imbalance compensation technique is needed at the receiver for LTE-advanced system with CA and MIMO. In this article, we analyze the effects of the phase noise and IQ imbalance in dual band MIMO-OFDM system, and propose a novel compensation scheme in order to enhance the system performance. From the simulation results, it can be seen that phase noise and IQ imbalance cause serious performance degradation of dual-band MIMO-OFDM system, and the proposed schemes has significantly improved BER performance by concurrent suppression of ICI due to phase noise and IQ imbalance.