Serving Cell RSRQ Measurement Using DMTC Period Segmentation

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Solution Overview

Problem

In wireless communication systems, especially in LTE environments, the presence of a small cell positioned in a serving cell can interfere with the measurement of reference symbol received quality (RSRQ) of the serving cell, even when the small cell is in an off state, due to the transmission of discovery reference signals (DRS) during specific timing configurations, affecting the accuracy of RSRQ measurements.

Innovation Solution

A method and apparatus for a user equipment (UE) to receive a DRS measurement timing configuration (DMTC) from the network, allowing it to measure RSRQ of the serving cell only during non-DMTC periods when no DRS is transmitted from the small cell, and in other periods when the small cell is on, enabling accurate RSRQ measurement by considering the small cell's state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If DRS is transmitted during DMTC period from small cell, then small cell can perform discovery signal transmission, but RSRQ measurement accuracy of serving cell deteriorates due to interference

Engineering Contradiction:

Improvesmall cell discovery signal transmissionVSAvoidRSRQ measurement accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The measurement period is segmented into DMTC periods (when small cell transmits DRS) and non-DMTC periods (when small cell does not transmit DRS). RSRQ measurements are performed specifically during non-DMTC periods to avoid interference from small cell DRS transmission, while still allowing small cell discovery and operation during DMTC periods.

Inventive Principle:

Principle #1Segmentation

2Productivity

If UE measures RSRQ during DMTC period, then measurement can be performed continuously, but measurement accuracy deteriorates due to small cell DRS interference

Engineering Contradiction:

Improvemeasurement continuityVSAvoidRSRQ measurement accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

RSRQ measurements are performed periodically during non-DMTC periods rather than continuously. This periodic measurement approach avoids the interference occurring during DMTC periods while still providing regular measurement updates for mobility management decisions.

Inventive Principle:

Principle #19Periodic action

3Object-affected harmful factors

If small cell is kept in off state, then interference to serving cell is reduced, but small cell cannot perform necessary DRS transmission for discovery

Engineering Contradiction:

Improveinterference to serving cellVSAvoidsmall cell discovery function

Core Design Contradiction:

Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The small cell is configured to transmit DRS periodically during designated DMTC periods rather than continuously. During non-DMTC periods, the small cell remains silent to avoid interference with serving cell RSRQ measurements, while still maintaining the ability to perform discovery and transmission during DMTC periods.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS10056995B2Method and apparatus for measuring RSRQ of serving cell on basis of DMTC

Publication Date: 2018.08.21 LG ELECTRONICS INC

AI summary

Provided is a method for a terminal for measuring the reference signal received quality (RSRQ) of a serving cell.The terminal receives a discovery reference signal (DRS) measurement timing configuration (DMTC) from a network, and on the basis of the received DMTC, the terminal can measure the RSRQ of the serving cell. The serving cell may comprise a small cell supporting a DRS, and the small cell may be present on the same frequency as the serving cell. Furthermore, the RSRQ measurement of the serving cell can only be carried out during a non-DMTC period set in accordance with the DMTC. The non-DMTC period is a period during which a DRS is not transmitted from the small cell.