DRS Reception in Unlicensed Band MBSFN Subframes

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Solution Overview

Problem

Wireless access systems face challenges in efficiently supporting unlicensed bands, particularly in rate matching of downlink transmission bursts and frequency reuse, as well as in accurately defining and transmitting discovery reference signals (DRS) during multicast service single frequency network (MBSFN) configurations.

Innovation Solution

A method for a user equipment (UE) to receive a discovery reference signal (DRS) in a wireless access system supporting an unlicensed band, involving the reception of high-layer signals indicating MBSFN subframes and setting a discovery measurement timing configuration (DMTC) period, allowing DRS transmission within this period, and applying MBSFN configuration only when necessary.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If MBSFN configuration is applied to all subframes in DMTC period, then multicast service coverage is improved, but DRS reception reliability deteriorates

Engineering Contradiction:

Improvemulticast service coverageVSAvoidDRS reception reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies MBSFN configuration selectively to specific subframes within the DMTC period rather than uniformly to all subframes. The eNodeB configures MBSFN subframes based on local conditions - applying MBSFN where multicast traffic requires it while leaving other subframes in normal mode to ensure reliable DRS transmission and reception.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If DRS is transmitted in MBSFN subframe, then DRS transmission flexibility is improved, but measurement precision deteriorates

Engineering Contradiction:

ImproveDRS transmission flexibilityVSAvoidRRM measurement precision

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent implements dynamic subframe configuration where the eNodeB can flexibly determine whether each subframe in the DMTC period should operate in MBSFN mode or normal mode. This dynamic adjustment allows the system to adapt to varying traffic conditions while ensuring that DRS transmissions occur in subframes with appropriate characteristics for accurate UE measurements.

Inventive Principle:

Principle #15Dynamics

3Productivity

If DMTC period is set to cover all possible DRS transmission opportunities, then DRS reception opportunity is improved, but time resource utilization deteriorates

Engineering Contradiction:

ImproveDRS reception opportunityVSAvoidtime resource utilization

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent segments the DMTC period into multiple subframes with different configurations. Instead of treating the entire DMTC period uniformly, the eNodeB divides it into specific MBSFN subframes and normal subframes, allowing UEs to perform DRS measurements only in appropriate subframes while other subframes are utilized for other purposes, thereby improving overall time resource utilization.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS11337050B2Method and device for transreceiving discovery reference signal in wireless access system supporting unlicensed band

Publication Date: 2022.05.17 LG ELECTRONICS INC

AI summary

A method for receiving a discovery reference signal (DRS) by a user equipment (UE) in a wireless communication system for supporting an unlicensed band, includes receiving the DRS in at least one subframe included in a discovery measurement timing configuration (DMTC) period, and receiving a multimedia broadcast multicast service single frequency network (MBSFN) configuration, wherein the MBSFN configuration is not applied to the at least one subframe.