Linear Interference Suppression With Covariance Mismatches in MIMO-OFDM Systems

Abstract—Interference cancellation is a key design concern for next-generation communication systems. One practical approach is the interference rejection combining (IRC) scheme, which is already being considered as the base receiver for next-generation 3GPP specifications. IRC treats interference as a stationary Gaussian process to facilitate simple interference suppression. However, this stationary assumption does not hold in practice; for example, the variances of the pilot signal and of the data signal from the interfering base station (eNB) are quite differ-ent. This considerably impacts the possible improvements of an interference-aware receiver. In this paper, novel interference sup-pression schemes are proposed, which handle separately the inter-fering pilot and the interfering data signals. The proposed schemes take into account channel estimation errors and the errors in esti-mating the covariance of interference plus noise. The performance of the proposed schemes is validated by using realistic channel models and asynchronous scenarios for MIMO-OFDM systems. Index Terms—Multi-user interference, MIMO-OFDM, imper-fect CSI