In this paper, we analyze the performance of a downlink beamforming system with partitioned vector quantization (P-VQ). A multiuser multiple-input single-output (MU-MISO) downlink beamforming system with accurate chan...
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ISBN:
(纸本)9781467362337
In this paper, we analyze the performance of a downlink beamforming system with partitioned vector quantization (P-VQ). A multiuser multiple-input single-output (MU-MISO) downlink beamforming system with accurate channel state information (CSI) at user terminals is considered. The optimization of feedback bits allocation to different partitions and channel direction indicator (CDI), channel quality indicator (CQI) corresponding to each partition has been performed exploiting quantization mean square error (MSE). The impacts of equal and unequal partitioning, and the number of partitions on codebook memory and overall system capacity have also been investigated and depicted through simulation results. We have found that with optimized CQI and CDI bits allocations, the amount of bits allotted to equal and unequal partitions are proportional to the size ratios of the respective partitioned sub-vectors. It has also been observed that for small-sized partitions, the optimal ratio of CDI to CQI is much smaller than that of large-sized partitions.
In this study, an adaptive and variable-rate feedback reduction technique for partitioned vector quantization (P-VQ) in MU-MISO downlink precoding is proposed. Independent feedback reduction is performed for both chan...
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ISBN:
(纸本)9781467361866
In this study, an adaptive and variable-rate feedback reduction technique for partitioned vector quantization (P-VQ) in MU-MISO downlink precoding is proposed. Independent feedback reduction is performed for both channel quality indicator (CQI) and channel direction indicator (CDI) over slowly-varying Rayleigh channel. The users adaptively reduce the feedback overhead for quantized channel state information (CSI) depending on the rate and direction of change in the correlated CQIs and CDIs. Simulation results show that the proposed scheme greatly lessens the communication overhead with very small performance loss and enhances the quantization efficiency.
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