Multiple precoder codebooks for MIMO systems with limited feedback of precoder and bit loading

In this paper we propose to use multiple precoder codebooks for MIMO systems with limited feedback of precoder and bit loading. One precoder codebook is designed for each bit loading vector in the bit loading codebook as bit loading contains information on the importance of individual subchannels. For each precoder codebook, we incorporate the associated bit loading in codebook design to minimize transmission power based on sequential vector quantization. There is no need of informing the transmitter which precoder codebook has been used as the information is conveyed by the bit loading feedback. Due to the exploitation of bit loading information, the proposed multi-codebook scheme outperforms the single-codebook scheme significantly as will be demonstrated by simulations.