Efficient Uniform Channel Quantization of Sparse CIR for Downlink OFDM Systems
Wireless Personal Communications Vol. 96, Nº 1, pp. 799 - 812, April, 2017.
ISSN (print): 1572-834X
ISSN (online): 0929-6212
Journal Impact Factor: 0,653 (in 2014)
Digital Object Identifier: 10.1007/s11277-017-4201-8
Channel state information at the transmitter side is an important issue for wireless communications systems, namely when precoding techniques are employed. Recent works explored random vector quantization (RVQ) as a solution for limited feedback for multi-user systems equipped with multiple antennas. Despite of being a good option for narrowband channels, this method requires large complexity and is not efficient for sparse channels. To overcome these drawbacks we consider a strategy based on uniform quantization, denoted partial uniform quantization (P-UQ), where just part of channel frequency response is quantized. This allows an efficient feedback of channel frequency response from the receivers to the transmitter, by using a reduced number of quantization bits. The comparison between the proposed P-UQ-based method and RVQ performed in this paper leads to the conclusion that the most advantageous method for sparse channels is the P-UQ.