Dynamic RSRP Weighted Average for Handover Target Cell Selection

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Solution Overview

Problem

Existing handover decision algorithms in cellular communication systems do not effectively consider incremental measurement reports or scaling factors, leading to unnecessary handovers and failures, especially for UEs with low speed or high speed Radio Link Failures, as they rely on static thresholds and do not calculate weighted averages of Reference Signal Received Power (RSRP) values.

Innovation Solution

A method and system that detect neighbor cells, receive periodic measurement reports from User Equipment (UE) with incremental weightages assigned to RSRP values, calculate a weighted average of RSRP values over time, and select the target cell with the highest weighted average for handover requests, thereby improving the reliability and efficiency of handover decisions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing handover decision algorithms use static thresholds and do not calculate weighted averages of RSRP values, then the handover decision process is simple, but unnecessary handovers and Radio Link Failures occur especially for UEs with low speed or high speed mobility

Engineering Contradiction:
Improvehandover reliabilityVSAvoidhandover decision algorithm complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies dynamics by transitioning from static handover thresholds to dynamic weighted average RSRP calculations. The system continuously updates the weighted average of Reference Signal Received Power values from multiple measurement reports, where weights are assigned based on the recency and reliability of measurements. This dynamic approach allows the handover decision to adapt to changing channel conditions and UE mobility patterns, thereby improving handover reliability without excessive complexity

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter used for handover decision from simple RSRP threshold comparison to weighted average RSRP calculation. By introducing weights that reflect the quality and recency of measurement reports, the system transforms the decision parameter into a more robust metric that accounts for measurement variations due to UE mobility. This parameter transformation reduces unnecessary handovers while maintaining algorithmic tractability

Inventive Principle:
Principle #35Parameter changes

2Reliability

If handover decision algorithm re-executes to determine another target cell after handover failure, then another target cell can be selected, but time is lost and additional failures may occur

Engineering Contradiction:
Improvehandover success rateVSAvoidhandover decision time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-calculating and maintaining a ranked list of candidate target cells based on their weighted average RSRP values before handover failure occurs. When a handover fails, the system can immediately select the next best candidate from the pre-evaluated list without re-executing the entire decision algorithm. This preliminary preparation significantly reduces the time required for alternative handover attempts and improves overall handover success rate

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If existing algorithms do not consider scaling factors of UE at eNodeB, then the algorithm is simpler, but unnecessary handovers occur for low speed UEs and Radio Link Failures occur for high speed UEs

Engineering Contradiction:
Improveadaptability to UE mobilityVSAvoidalgorithm complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by introducing UE-specific scaling factors that adapt the handover decision to the mobility characteristics of individual UEs. The scaling factor is determined based on UE speed and mobility pattern, allowing the algorithm to adjust the sensitivity of handover triggers locally for each UE. This enables the system to prevent unnecessary handovers for low-speed UEs while facilitating timely handovers for high-speed UEs, improving adaptability without significantly increasing overall system complexity

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3029996B1Target cell selection during handover
Publication Date: 2017.10.04 TATA CONSULTANCY SERVICES LTD
  • EP3029996B1 patent drawingFigure 1
  • EP3029996B1 patent drawingFigure 2
  • EP3029996B1 patent drawingFigure 3

AI summary

Systems and methods for selecting a target cell during a handover procedure at a serving cell are disclosed. A plurality of neighbor cells is detected. A plurality of Measurement Reports (MRs) comprising Reference Signal Received Power (RSRP) values of the plurality of neighbor cells is received from the user equipment (UE). Incremental weightages are assigned to the RSRP values of each MR of the plurality of MRs. Based on the RSRP and the incremental weightages assigned, a weighted average of the RSRP values for each neighbor cell is calculated. Based on the weighted average, a target cell is selected to send a handover request. A target cell is selected from the plurality of neighbor cells based on the weighted average of the RSRP values. the target cell is selected based on a periodic interval time and scaling factors as per UE speed to determine the handover.