MIMO Broadcast Channels with Block Diagonalization and Finite Rate Feedback
<|reference_start|>MIMO Broadcast Channels with Block Diagonalization and Finite Rate Feedback: Block diagonalization is a linear precoding technique for the multiple antenna broadcast (downlink) channel that involves transmission of multiple data streams to each receiver such that no multi-user interference is experienced at any of the receivers. This low-complexity scheme operates only a few dB away from capacity but does require very accurate channel knowledge at the transmitter, which can be very difficult to obtain in fading scenarios. We consider a limited feedback system where each receiver knows its channel perfectly, but the transmitter is only provided with a finite number of channel feedback bits from each receiver. Using a random vector quantization argument, we quantify the throughput loss due to imperfect channel knowledge as a function of the feedback level. The quality of channel knowledge must improve proportional to the SNR in order to prevent interference-limitations, and we show that scaling the number of feedback bits linearly with the system SNR is sufficient to maintain a bounded rate loss. Finally, we investigate a simple scalar quantization scheme that is seen to achieve the same scaling behavior as vector quantization.<|reference_end|>
@article{ravindran2006mimo,
    title={MIMO Broadcast Channels with Block Diagonalization and Finite Rate
  Feedback},
    author={Niranjay Ravindran and Nihar Jindal},
    journal={arXiv preprint arXiv:cs/0610077},
    year={2006},
    archivePrefix={arXiv},
    eprint={cs/0610077},
    primaryClass={cs.IT math.IT}
}