Mobile Station Handover Capability Detection

Solution Overview

Problem

In cellular communication systems, handover to uncontrolled cells is challenging due to the lack of control by network operators over the location and operation of these cells, leading to uncertainties about handover capability, resulting in delays and wasted signaling as the serving cell may incorrectly assume handover support, causing unnecessary preparation attempts and potential loss of coverage.

Innovation Solution

Implementing a method within the mobile station and cell controllers to determine whether a target cell supports inbound handover by receiving explicit indications from the target cell or through failed handover preparation attempts, and storing this information to avoid future attempts, using specific physical layer addresses for supported handovers, and modifying messages like Packet Cell Change Continue and Packet Cell Change Order to indicate handover support or lack thereof.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the serving cell attempts handover to an uncontrolled target cell without knowing its handover capability, then the serving cell may initiate handover preparation, but this causes signaling waste and delays when the target cell does not support inbound handover

Engineering Contradiction:

Improvehandover execution efficiencyVSAvoidhandover preparation delay

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The mobile station performs preliminary detection of the target cell's inbound handover support capability before the serving cell initiates handover preparation. The MS receives an indication from the target cell (directly or via serving cell) about whether inbound handover is supported, and uses this information to prevent unnecessary handover preparation attempts, thereby avoiding signaling waste and delays

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements a feedback mechanism where the target cell's handover support capability is communicated back to the mobile station and/or serving cell. This feedback loop allows the serving cell to make informed decisions about handover preparation based on the target cell's actual capability, preventing wasted signaling attempts

Inventive Principle:

Principle #23Feedback

2Reliability

If the serving cell initiates handover preparation to an uncontrolled target cell, then handover may be enabled, but unnecessary preparation attempts are made when the target cell does not support handover, causing signaling waste

Engineering Contradiction:

Improvehandover capability determination accuracyVSAvoidsignaling waste

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The mobile station performs preliminary detection of the target cell's inbound handover support capability before the serving cell initiates handover preparation. The MS receives an indication from the target cell (directly or via serving cell) about whether inbound handover is supported, and uses this information to prevent unnecessary handover preparation attempts, thereby avoiding signaling waste

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements a feedback mechanism where the target cell's handover support capability is communicated back to the mobile station and/or serving cell. This feedback loop allows the serving cell to make informed decisions about handover preparation based on the target cell's actual capability, preventing wasted signaling attempts

Inventive Principle:

Principle #23Feedback

3Ease of operation

If the serving cell does not have explicit identification information for the uncontrolled target cell, then the serving cell cannot communicate with the target cell controller, but the mobile station may still need to perform cell change

Engineering Contradiction:

Improvecell change capabilityVSAvoidtarget cell identification information

Core Design Contradiction:

Ease of operationVSLoss of information

Solution Approach 1:

The mobile station autonomously determines the target cell's inbound handover support capability by detecting the target cell and receiving handover support indication information. This self-service capability allows the MS to perform cell change operations even when the serving cell lacks explicit identification information for uncontrolled target cells

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The mobile station acts as an intermediary that bridges the information gap between the serving cell and uncontrolled target cell. The MS detects the target cell's handover support capability and communicates this information to the serving cell, enabling the serving cell to make informed handover decisions without having prior explicit identification information

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentEP2526716B1Systems and methods for informing serving cell of target cell handover capability

Publication Date: 2018.10.17 BLACKBERRY LTD

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AI summary

Systems and methods of informing a serving cell of a target cell handover capability are provided. In some cases, a mobile station determines whether inbound handover is possible and communicates this to the serving cell. The mobile station may make this determination based on broadcast information from the target cell. Alternatively, the mobile station may make this determination based on a message generated by a target cell controller that is sent to the mobile station through the serving cell. In another example, the mobile station construes the absence of a response to a cell change notification as an indication that inbound handover to the target cell is not possible.