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Method and apparatus for switching between flat feedback mode and hierarchical feedback mode

A hierarchical feedback and flat feedback technology, applied in baseband systems, radio transmission systems, digital transmission systems, etc., can solve problems such as inefficient use of feedback overhead

Active Publication Date: 2014-12-03
ALCATEL LUCENT SHANGHAI BELL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, hierarchical feedback may lead to an inefficient use of feedback overhead when the time or frequency correlation of the channel is low

Method used

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  • Method and apparatus for switching between flat feedback mode and hierarchical feedback mode
  • Method and apparatus for switching between flat feedback mode and hierarchical feedback mode
  • Method and apparatus for switching between flat feedback mode and hierarchical feedback mode

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Embodiment Construction

[0018] Hereinafter, the present invention will be described based on the accompanying drawings. In the following description, some specific embodiments are only for the purpose of description, which should not be construed as any limitation on the present invention, but are only examples. Conventional structures or constructions will be omitted when it may cause to obscure the understanding of the present invention.

[0019] The idea of ​​hierarchical feedback stems from improving feedback accuracy and improving the overall performance of wireless communication systems with limited feedback. The hierarchical feedback mechanism utilizes the correlation of the physical channel in the time or frequency domain. Codebooks in hierarchical feedback are organized in a binary tree structure, and the codeword-coupled indices in a given subtree at level j have the same (j-1) effective bits, as figure 1 shown.

[0020] When the channel varies slowly, the codewords corresponding to adja...

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Abstract

The present invention provides a method for switching between a flat feedback mode and a hierarchical feedback mode in a mobile communication system, which includes: feeding back the precoding matrix index from a user terminal to a base station in the flat feedback mode, after associating the user terminal with the base station; monitoring the measurement which indicates the channel change speed of the user terminal; judging whether the measurement which indicates the channel change speed of the user terminal exceeds a predetermined threshold; and if judging that the measurement which indicates the channel change speed of the user terminal exceeds the predetermined threshold, feeding back the precoding matrix index from the user terminal to the base station by switching from the flat feedback mode to the hierarchical feedback mode.

Description

technical field [0001] The present invention relates to the field of mobile communication, and more particularly, to a method and device for switching between flat feedback mode and hierarchical feedback mode in a mobile communication system, which can adapt different feedback modes according to the channel conditions of a user terminal (UE). Feedback mode, and the hierarchical feedback mode can be used to improve the feedback accuracy when the channel changes slowly. Background technique [0002] In the Long Term Evolution Release 8 (LTE Re1-8) specification, SU-MIMO (Single User Multiple-Input Multiple-Output) is specially optimized for feedback strategies and codebooks. However, it is known that MU-MIMO is more sensitive to feedback accuracy than SU-MIMO. Low feedback accuracy will lead to poor MU-MIMO performance, thus hindering the exploitation of the theoretical potential of MU-MIMO. In order to solve this problem, recent discussions of LTE-A focus on advanced feedba...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04W72/00
CPCH04L2025/03426H04L1/003H04L25/03343H04B7/0643H04L2025/03808H04B7/0639H04L5/0023
Inventor 吕荻杨红卫
Owner ALCATEL LUCENT SHANGHAI BELL CO LTD