Base Station Logical Cell Segmentation for 256 QAM Measurement

Solution Overview

Problem

Current 3GPP LTE base stations with higher transmission power struggle to implement 256 QAM modulation due to hardware complexity and cost, while power backoff reduces cell coverage variability but complicates UE measurement and handover processes.

Innovation Solution

Implementing a method where a base station operates as two logical cells, using 64 QAM on one subframe set and 256 QAM on another with power backoff, allowing UE to perform measurements and send reports for each, and enabling handovers between these logical cells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a base station uses power backoff to support 256 QAM modulation, then 256 QAM can be implemented in base stations with higher transmission power, but cell coverage size varies abnormally and measurement results become abnormal

Engineering Contradiction:

Improve256 QAM support capabilityVSAvoidmeasurement result accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The base station is divided into two logical cells: a first logical cell operating without power backoff (using 64 QAM or lower) and a second logical cell operating with power backoff (enabling 256 QAM). This segmentation allows the system to support 256 QAM in specific subframes while maintaining stable coverage in others, resolving the measurement accuracy issue caused by uniform power backoff across all subframes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The base station dynamically switches between different power backoff states across different subframe sets. The first subframe set operates with normal power (no backoff) while the second subframe set operates with power backoff applied. This dynamic approach allows the base station to support 256 QAM modulation in the second subframe set while maintaining stable cell coverage and accurate measurement results in the first subframe set.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If a base station uses power backoff to support 256 QAM modulation, then 256 QAM can be implemented in base stations with higher transmission power, but cell coverage size varies abnormally causing abnormal cell reselection and handover

Engineering Contradiction:

Improve256 QAM support capabilityVSAvoidcell reselection and handover stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The base station is divided into two logical cells: a first logical cell operating without power backoff (using 64 QAM or lower) and a second logical cell operating with power backoff (enabling 256 QAM). This segmentation allows the system to support 256 QAM in specific subframes while maintaining stable coverage in others, resolving the measurement accuracy issue caused by uniform power backoff across all subframes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The base station applies power backoff periodically in the second subframe set while maintaining normal power in the first subframe set. This periodic application of power backoff allows the base station to support 256 QAM modulation during specific time intervals (second subframe set) while maintaining stable cell coverage and reliable handover behavior during other intervals (first subframe set).

Inventive Principle:

Principle #19Periodic action

3Adaptability or versatility

If a base station uses power backoff to support 256 QAM modulation, then 256 QAM can be implemented in base stations with higher transmission power, but hardware complexity and cost increase

Engineering Contradiction:

Improve256 QAM support capabilityVSAvoidbase station hardware complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The base station changes the power backoff parameter dynamically across different subframe sets. By applying power backoff only in the second subframe set (enabling 256 QAM) and not in the first subframe set (using 64 QAM or lower), the system achieves 256 QAM support without requiring hardware modifications. This parameter-based approach avoids the need for additional hardware components, reducing complexity and cost compared to hardware-based solutions.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9661548B2Method and terminal for executing measurement

Publication Date: 2017.05.23 LG ELECTRONICS INC

AI summary

A disclosure of the present specification presents a method for executing measurement including: measuring a first and a second logical cell of a base station and measuring a cell of a neighboring base station; and executing cell reselection according to a result of the measuring or transmitting a measurement report including the result of the measuring to the base station. In the method, since the base station operates the first logical cell in a first sub-frame set within a wireless frame and operates the second logical cell in a second sub-frame set within the wireless frame to which power backoff is applied, the measuring of the first logical cell by the base station may be executed in the first sub-frame set and the measuring of the second logical cell by the base station may be executed in the second sub-frame set to which the power-back off is applied.