Channel estimation for LTE and LTE-A MU-MIMO uplink with a narrow transmission band

The 3GPP LTE and LTE-A standards provide for multi-user multi-input multi-output (MU-MIMO) transmission in the uplink. But the property of reference signals (RSs) is such that care must be exercised in channel estimation to minimize the interference among different antenna channels. Typical DFT- and DCT-based channel estimation methods have low complexity but may yield relatively high inter-channel interference, especially when user equipments (UEs) are allocated narrow transmission bands. Methods that can attain better channel separation often have much higher computational requirements. In this paper, we propose an MU channel estimation technique that seeks to minimize an L₁ norm of error. It does not need second-order statistics as the linear minimum mean-square error (LMMSE) technique, has good numerical properties, and yields a performance between the least-square (LS), the DFT, and the LMMSE techniques.