Codebook Tables for Encoding and Decoding Partial Channel State Information in a Multiple-Input Multiple-Output (MIMO) System

Background Multiple-input multiple-output (MIMO) communication systems can use channel state information to improve performance in wireless links. A practical way to obtain channel state information at the transmitter is through codebook-based closed-loop transmit diversity methods, known broadly as limited feedback techniques. Codebook-based closed-loop transmit diversity method utilizes codebook tables known to both the transmitter and the receiver. Codebook methods have been included in the IEEE 802.16e, 3GPP LTE, and 3GPP2 UMB standards, among others

The choice of the codebook is important in codebook-based MIMO techniques. Prior art considered either codebooks designed under certain optimality criteria but which practically required high storage and high precision operations to search, or practically motivated codebooks that sacrificed performance.

Invention Description In this invention, a new codebook that facilitates efficient searching is described, along with a method for constructing precoding codebooks of different dimensions. The codebook table described herein has the advantage of reduced storage requirements and simple computational procedure, which is beneficial for fast adaptation in rapidly changing channel environments.

Furthermore, it has been shown that the proposed codebook provides performance equal to or better than previously known high precision codebooks. Additionally, a novel method and apparatus for codeword selection at the receiver and encoding at the transmitter is described which does not require high-precision complex number arithmetic.

Benefits

Reduced storage requirements. Beneficial for fast adaptation to rapidly changing channel environments.

Features

Provides performance equal to or better than previously known high-precision codebook tables Does not require high-precision complex number arithmetic Small storage requirements

Market Potential/Applications Present and future MIMO communication equipments, such as in IEEE 802.11n, IEEE 802.16e/m, 3GPP LTE, 3GPP LTE-Advanced, 3GPP2 UMB, and future wireless standards which may employ multiple antenna technologies

IP Status One U.S. patent application filed

UT Researcher Robert W. Heath, Jr., Ph.D., Electrical and Computer Engineering, The University of Texas at Austin Takao Inoue, Electrical and Computer Engineering, The University of Texas at Austin

Type of Offer: Licensing



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