Base Station Offset Signaling for Accurate Channel State Information

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Solution Overview

Problem

In heterogeneous wireless networks, there is an interference mismatch problem between reference signals and data symbols, leading to inaccurate channel state information calculation, which affects communication reliability and spectrum efficiency.

Innovation Solution

A method where user equipment estimates and compensates Signal to Interference and Noise Ratios (SINR) for subframes interfered by Almost Blank Subframes and non-Almost Blank Subframes, using offset values received from the base station to calculate more accurate channel state information, which is then transmitted back to the base station.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If pico base station transmission power is increased to expand cell size, then coverage area is improved, but base station cost and size increase

Engineering Contradiction:

Improvepico base station cell sizeVSAvoidbase station cost and size

Core Design Contradiction:

Area of stationary objectVSEase of manufacture

Solution Approach 1:

The patent changes the parameter of transmission power dynamically by introducing a cell selection offset that favors pico base stations. This allows the effective coverage area to be expanded without physically increasing the transmission power hardware, thereby avoiding increased cost and size while achieving the desired coverage expansion.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If cell selection offset is used to favor pico base station selection, then uplink connection to pico base station is improved, but downlink interference from macro base station increases

Engineering Contradiction:

Improveuplink connection reliabilityVSAvoiddownlink interference

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by implementing interference coordination specifically at the cell border regions where macro-pico interference occurs. The eNodeB identifies user equipment in interference-prone areas and applies targeted interference mitigation techniques, rather than uniformly reducing power across the entire cell, thus maintaining uplink reliability while minimizing downlink interference.

Inventive Principle:

Principle #3Local quality

3Measurement precision

If reference signals are used for channel estimation, then channel state information is obtained, but interference mismatch between reference signals and data symbols occurs

Engineering Contradiction:

Improvechannel state information accuracyVSAvoidcommunication reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent implements feedback by having the eNodeB measure the interference on PDSCH resources, calculate an interference offset, and signal this offset to the UE. The UE then uses this feedback information to compensate for the interference mismatch when calculating channel state information, ensuring both measurement precision and communication reliability are maintained.

Inventive Principle:

Principle #23Feedback

4Productivity

If heterogeneous networks are deployed to increase data rates, then network capacity is improved, but interference management complexity increases

Engineering Contradiction:

Improvenetwork data rateVSAvoidinterference management complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent applies self-service by enabling the eNodeB to autonomously measure interference on PDSCH resources, calculate the appropriate interference offset, and signal it to UEs without requiring complex centralized coordination. This self-service approach allows heterogeneous networks to achieve high data rates while keeping interference management relatively simple and decentralized.

Inventive Principle:

Principle #25Self-service

Data Source

PatentEP2810474B1Base station, user equipment, and methods therein in a communications system

Publication Date: 2020.03.25 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

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AI summary

A method in a first base station for obtaining channel state information from a user equipment is provided. The first base station is comprised in a wireless communication system. The wireless communication system further comprises the user equipment. The first base station estimates (403) a first offset value for a first set of subframes based on a first channel information. The first base station further estimates (404) a second offset value for a second set of subframes based on a second channel information. The first base station transmits (405) the estimated first offset value and the estimated second offset value to the user equipment. The first base station then obtains (407) channel state information from the user equipment. The channel state information is based on the transmitted estimated first offset value and the estimated second offset value. The channel state information is to be used for transmission in the first base station.