Adaptive Hysteresis Handover Control for Wireless Base Stations

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Solution Overview

Problem

In wireless communication systems, handover failures occur due to factors like channel status changes and resource depletion at target base stations, leading to a high handover failure rate, which is influenced by the algorithm used for deciding handover execution without considering load status changes of both base stations.

Innovation Solution

A method and system for deciding handover execution in a wireless communication system that involves determining a hysteresis value based on traffic loads, movement speed, and traffic distribution of both the source and target base stations, and only executing handover when the signal strength difference between the two is maintained above the hysteresis value for a predetermined time, thereby minimizing handover failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If handover is executed based on fixed threshold rules without considering load status, then handover decision simplicity is maintained, but handover failure rate increases

Engineering Contradiction:

Improvehandover success rateVSAvoidhandover decision algorithm complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the handover decision algorithm adaptive rather than static. The base station dynamically adjusts handover parameters based on real-time load status information exchanged between source and target base stations. This allows the system to respond to changing network conditions, improving handover success rates without requiring overly complex predetermined rules.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent implements feedback mechanisms where target base stations provide load status information back to source base stations before handover execution. This feedback loop enables source base stations to make informed handover decisions by considering current network conditions at target cells, thereby reducing handover failures caused by resource depletion while maintaining reasonable algorithmic complexity.

Inventive Principle:

Principle #23Feedback

2Reliability

If handover is executed without considering target base station load status, then handover execution speed is maintained, but resource depletion at target base station occurs

Engineering Contradiction:

Improveresource availability at target base stationVSAvoidhandover decision time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by having target base stations prepare and communicate their load status information to source base stations before handover is actually executed. This advance preparation allows source base stations to assess whether target cells have sufficient resources, preventing handovers to overloaded cells and avoiding resource depletion issues while maintaining efficient handover timing.

Inventive Principle:

Principle #10Preliminary action

3Speed

If handover threshold is set low for quick handover, then handover responsiveness is improved, but frequent handovers due to shadow fading increase

Engineering Contradiction:

Improvehandover response speedVSAvoidcommunication service stability

Core Design Contradiction:

SpeedVSProductivity

Solution Approach 1:

The patent applies dynamics by adjusting handover thresholds adaptively rather than using fixed low thresholds. The system dynamically modifies threshold values based on signal strength measurements, shadow fading conditions, and network load status. This allows the system to respond quickly to legitimate handover needs while filtering out spurious handover requests caused by temporary shadow fading effects.

Inventive Principle:

Principle #15Dynamics

4Reliability

If handover is executed without load status consideration, then system complexity is reduced, but service quality during handover deteriorates

Engineering Contradiction:

Improveservice quality continuityVSAvoidbase station coordination complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements feedback where target base stations send load status information to source base stations, enabling informed handover decisions that maintain service quality. The feedback mechanism is designed to be efficient, exchanging only necessary load status parameters rather than comprehensive network state information, thereby maintaining service quality without excessive coordination complexity.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS9119126B2Method for determining handover in wireless communication system and base station therefor

Publication Date: 2015.08.25 KT CORP

AI summary

A handover decision is capable of lowering a handover failure rate of horizontal handover between a source base station and a target base station in a wireless communication system. After deciding a target base station to which the mobile terminal is to be handed over, a hysteresis value for determining a handover execution point is decided, and execution of the handover of the mobile terminal occurs when a difference between the received signal strength of a signal received from the target base station to the mobile terminal and the received signal strength of a signal received from the source base station to the mobile terminal is continuously maintained at the hysteresis value or above during a predetermined time.