Limited feedback scheme in the presence of feedback delay using Kalman filter

In this paper, a Best-M feedback scheme using Kalman filter is proposed to reduce the uplink feedback overhead in the presence of feedback delay. Best-M feedback scheme is an effective method to reduce the number of the channel quality information (CQI) feedback. However, the CQI feedback after the conventional Best-M decision is inaccurate for base station (BS) scheduling due to the feedback delay and the time varying nature of the channel. A modified limited feedback scheme is proposed to use a Kalman filter to compensate for the performance degradation caused by the feedback delay in Best-M feedback scheme. In the proposed scheme, the user equipment (UE) exploits a Kalman filter to predict the signal to interference plus noise ratio (SINR). Then, the UE makes the Best-M decision based on this predicted SINR and sends the corresponding CQI back to the BS. The simulation results show that the Best-M feedback scheme using Kalman filter, which achieves the same feedback reduction as the conventional scheme, improves the system spectral efficiency.