Tree-Structured Random Vector Quantization for Limited-Feedback Wireless Channels
Abstract
We consider the quantization of a transmit beamforming vector in multiantenna channels and of a signature vector in code division multiple access (CDMA) systems. Assuming perfect channel knowledge, the receiver selects for a transmitter the vector that maximizes the performance from a random vector quantization (RVQ) codebook, which consists of independent isotropically distributed unit-norm vectors. The quantized vector is then relayed to the transmitter via a rate-limited feedback channel. The RVQ codebook requires an exhaustive search to locate the selected entry. To reduce the search complexity, we apply generalized Lloyd or -dimensional (kd)-tree algorithms to organize RVQ entries into a tree. In examples shown, the search complexity of tree-structured (TS) RVQ can be a few orders of magnitude less than that of the unstructured RVQ for the same performance. We also derive the performance approximation for TS-RVQ in a large system limit, which predicts the performance of a moderate-size system very well.
Keywords
Cite
@article{arxiv.1104.4607,
title = {Tree-Structured Random Vector Quantization for Limited-Feedback Wireless Channels},
author = {Wiroonsak Santipach and Kritsada Mamat},
journal= {arXiv preprint arXiv:1104.4607},
year = {2015}
}