Uppsala universitet

Diversity-Enhanced Equal Access - Considerable Throughput Gains with 1-bit Feedback.

Mathias Johansson

IEEE SPAWC 2004 (Signal Processing Advances in Wireless Communications),
Lissabon, Portugal, July 11-14 2004.   © IEEE


Abstract:
We investigate performance aspects of adaptive modulation and scheduling as the amount of channel feedback is reduced. We study throughput, fairness and the sensitivity to incorrect channel quantizations.

A main finding is that the throughput of a cellular downlink using strict multiuser diversity does not degrade significantly when the channel information is heavily quantized. On the other hand, unfairness increases and due to an inherent sensitivity to incorrectly chosen quantization levels there is a risk of occasional drastic performance drops.

Noting that fixed-access schemes do not have the bad properties of multiuser diversity, but achieve unsatisfactory throughput, we propose a scheme combining the good aspects of multiuser diversity with the desirable properties of fixed access schemes. The result is a low-complexity scheduler and quantization policy that achieve large throughput gains as compared to fixed access without compromising fairness.

Related publications:
Ph.D Thesis by Mathias Johansson.
SPAWC03 paper on use of 1-bit feedback.
RVK02 paper on multiuser diversity and maximum entropy scheduling.
Globecom 2001 paper.

Source:
Pdf, (114K)

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