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Adaptive precoding based on channel state information reliability

A technology of channel state information and precoding, which is applied in the field of spatial precoding, and can solve problems such as the occasional problem of unreliable precoder information for a single mobile terminal

Inactive Publication Date: 2015-02-25
TELEFON AB LM ERICSSON (PUBL)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Clearly, enabling CRS is not an energy-efficient solution to the occasional problem of unreliable or non-existent precoder information for a single mobile terminal

Method used

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  • Adaptive precoding based on channel state information reliability
  • Adaptive precoding based on channel state information reliability
  • Adaptive precoding based on channel state information reliability

Examples

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Embodiment Construction

[0030] The invention is described more fully hereinafter with reference to the accompanying drawings, in which examples of embodiments of the invention are shown. This invention may, however, be embodied in different forms and should not be construed as limited to the specific embodiments set forth herein. It should also be noted that these embodiments are not mutually exclusive. Thus, it may be assumed that a component or feature from one embodiment is present in or used in another embodiment where such inclusion is appropriate.

[0031] For purposes of illustration and explanation only, the present invention is described herein in the context of operating in a radio access network (RAN) communicating with wireless terminals (also referred to as user equipment or "UE") over wireless communication channels These and other examples of . More specifically, it is described in the context of systems using the Long Term Evolution (LTE) technology, also known as the Evolved UMTS T...

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PUM

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Abstract

In a system using spatial precoding, in the event that reliable channel state information is unavailable, a transmitting node uses an extended transmission mode, in which the precoders applied to data within each of several groups of time-frequency resources vary according to frequency. The extended transmission mode creates a frequency-selective variation in precoders, which may appear to be random, while using DMRS-based transmission. This variation is achieved by applying different precoders to the resource elements carrying data, using a pattern of precoder variation that is known to the receiving device. The precoding applied to DMRS within a given group of time-frequency resources is held constant-thus, the varying precoders within a given group of time-frequency resources are only applied to data elements, not to the DMRS resource elements.

Description

technical field [0001] The present invention relates generally to wireless communication systems and, more particularly, to techniques for spatially precoding signals transmitted from multiple antennas. Background technique [0002] In many wireless communication systems, wireless receivers use one or more of various types of pilot signals to assist in demodulating received signals. These pilot signals are often referred to as reference signals and / or reference symbols. In the 3rd Generation Partnership Project (3GPP) specification for the Long Term Evolution (LTE) wireless system (also commonly referred to as the Evolved UMTS Terrestrial Radio Access Network or E-UTRAN), the receiving wireless device has two different There are two frequency signal types used for data demodulation, namely, Common Reference Signal (CRS) and Demodulation Reference Signal (DMRS). In 3GPP specifications, for example, in Evolved Universal Terrestrial Radio Access (E-UTRA); Physical channels an...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L5/00H04L27/26H04L25/03H04L25/02
CPCH04L27/261H04L25/03343H04L5/0023H04L5/0048H04L25/0222H04L25/03949H04W72/0446
Inventor 弗雷德里克·努德斯特伦本特·林多夫
Owner TELEFON AB LM ERICSSON (PUBL)
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