Intercarrier Interference Self-Cancellation Space-Frequency Codes for MIMO-OFDM

Abstract

Abstract—Space-frequency (SF) codes that exploit both spatial and frequency diversity can be designed using orthogonal fre-quency division multiplexing (OFDM). However, OFDM is sen-sitive to frequency offset (FO), which generates intercarrier in-terference (ICI) among subcarriers. We investigate the pair-wise error probability (PEP) performance of SF codes over quasistatic, frequency selective Rayleigh fading channels with FO. We prove that the conventional SF code design criteria remain valid. The negligible performance loss for small FOs (less than 1%), however, increases with FO and with signal to noise ratio (SNR). While di-versity can be used to mitigate ICI, as FO increases, the PEP does not rapidly decay with SNR. Therefore, we propose a new class of SF codes called ICI self-cancellation SF (ISC-SF) codes to combat ICI effectively even with high FO (10%). ISC-SF codes are con-structed from existing full diversity space-time codes. Importantly, our code design provide a satisfactory tradeoff among error correc-tion ability, ICI reduction and spectral efficiency. Furthermore, we demonstrate that ISC-SF codes can also mitigate the ICI caused by phase noise and time varying channels. Simulation results affirm the theoretical analysis. Index Terms—Inter-carrier interference (ICI), multiple input multiple output (MIMO), orthogonal frequency division multiplex-ing (OFDM), space-frequency (SF) codes. I.