Performance of Partitioned Vector Quantization with Optimized Feedback Budget Allocation

Mirza Golam KIBRIA  Hidekazu MURATA  Susumu YOSHIDA  

IEICE TRANSACTIONS on Communications   Vol.E97-B   No.6   pp.1184-1194
Publication Date: 2014/06/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E97.B.1184
Type of Manuscript: PAPER
Category: Terrestrial Wireless Communication/Broadcasting Technologies
partitioned vector quantization,  feedback budget optimization,  multiuser-MISO,  Nonlinear precoding,  

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This study analyzes the performance of a downlink beamformer with partitioned vector quantization under optimized feedback budget allocation. A multiuser multiple-input single-output downlink precoding system with perfect channel state information at mobile stations is considered. The number of feedback bits allocated to the channel quality indicator (CQI) and the channel direction indicator (CDI) corresponding to each partition are optimized by exploiting the quantization mean square error. In addition, the effects of equal and unequal partitioning on codebook memory and system capacity are studied and elucidated through simulations. The results show that with optimized CQI-CDI allocation, the feedback budget distributions of equal or unequal partitions are proportional to the size ratios of the partitioned subvectors. Furthermore, it is observed that for large-sized partitions, the ratio of optimal CDI to CQI is much higher than that for small-sized partitions.