Abstract—Conventional precoded spatial multiplexing multiple-input multiple-output (MIMO) systems using limited feedback are mainly based on the notion of time invariant channels throughout transmission. Consequ-encely, the precoding matrix can be found during the training symbols and used over the subsequent data symbols. In this paper, a more practical system where the channel varies from one block of symbols to another is considered. In such scenario, the precoding matrix designed at the receiver based on the previous training symbols becomes outdated, which results in significant system performance degradation. In order to avoid this problem, and reduce performance degradation, we propose the use of a Kalman filter linear predictor at the receiver to provide the transmitter with the precoding matrix for the next block of symbols. The performance of this method is assessed using computer simulation, and the obtained results for the proposed channel prediction demonstrate improved bit error rate performance for time-varying Rayleigh fading channels.

Index Terms—feedback delay, Kalman filter, limited feedback, MIMO systems, spatial multiplexing

Cite: Abdullatif S. Kharwat, "Precoded Spatial Multiplexing MIMO Systems in Time- Varying Fading Channel," Journal of Communications, vol. 9, no. 2, pp. 118-125, 2014. Doi: 10.12720/jcm.9.2.118-125