Trellis-based feedback reduction for multiple input multiple output orthogonal frequency division multiplexing (MIMO-OFDM) with rate-limited feedback

摘要

Trellis-based methods for reducing feedback while maintaining performance in a Multiple Input, Multiple Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) system. The methods involve: receiving a plurality of symbols from a plurality of sub-carriers at a receiver; selecting a plurality of indices of codewords corresponding to a codebook of pre-coding weighting matrices for the sub-carriers based on vector quantization compression of the codewords, including selecting a plurality of indices based on trellis-based feedback encoding; and transmitting the selected indices over a wireless channel to a transmitter. Optimal precoding matrices are selected at the same time for all subcarriers by searching for the optimum choice of matrices along a trellis. Selecting a plurality of indices based on trellis-based feedback encoding includes constructing a trellis by specifying a state transition table.