Dual-Cell Serving Cell Change Preconfiguration

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Solution Overview

Problem

The existing Dual-Cell HSDPA technology does not effectively handle serving cell changes in multi-cell wireless transmit receive units, leading to unacceptable rates of dropped calls due to delays and service discontinuity, especially when a second carrier is introduced in the downlink, as it does not account for both carriers in the enhanced serving cell change procedure.

Innovation Solution

A method and apparatus for implementing serving cell changes in multi-cell WTRUs by preconfiguring primary and secondary serving cells and performing handovers using preconfigured information, allowing for seamless transitions between cells based on signal strength measurements and network confirmation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional serving cell change procedure is used in Dual-Cell HSDPA, then backward compatibility with Release 7, 6, and 5 devices is maintained, but service discontinuity and packet loss occur due to delays during handover

Engineering Contradiction:

Improveservice continuityVSAvoidhandover delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by preconfiguring the WTRU with serving cell information for both primary and secondary carriers before handover is needed. This includes pre-receiving and storing cell change indicators and preconfiguring measurement parameters, so that when handover is triggered, the WTRU can immediately execute the change without delay, thus resolving the contradiction between service continuity and handover delay

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements beforehand cushioning by preconfiguring the WTRU with all necessary handover parameters and indicators before the actual handover event. This cushioning preparation ensures that no service discontinuity occurs during the transition, as all configuration elements are already in place and ready for immediate activation, eliminating the harmful delay effect

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Productivity

If a second carrier is added in Dual-Cell HSDPA, then downlink throughput is increased, but the existing serving cell change procedure fails to account for both carriers, leading to dropped calls

Engineering Contradiction:

Improvedownlink throughputVSAvoidcall continuity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies universality by creating a unified serving cell change procedure that handles both primary and secondary carriers simultaneously. The WTRU is configured to monitor and execute cell changes for both carriers using a single integrated mechanism, making the handover procedure universal across multi-carrier operations, thus maintaining call continuity while supporting increased throughput from multiple carriers

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent uses preliminary action to preconfigure the WTRU with serving cell information for both primary and secondary carriers before handover is triggered. This includes pre-receiving cell change indicators for both carriers and preconfiguring measurement parameters, ensuring that when handover is needed, both carriers can be switched simultaneously without causing dropped calls, thereby maintaining reliability while supporting higher throughput

Inventive Principle:

Principle #10Preliminary action

3Speed

If preconfiguration of serving cell information is implemented, then handover speed is improved, but device complexity increases due to additional configuration management

Engineering Contradiction:

Improvehandover execution speedVSAvoidconfiguration management complexity

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by having the network preconfigure the WTRU with all necessary serving cell information before handover is needed. This includes pre-transmitting cell change indicators and preconfiguring measurement parameters through RRC messages, so that the WTRU storage already contains all required configuration elements. This approach speeds up handover execution while distributing the complexity burden to the network side rather than the device side

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses the RRC (Radio Resource Control) layer as an intermediary to manage the complexity of preconfiguration. The RRC messages serve as the medium through which the network preconfigures the WTRU with serving cell information, cell change indicators, and measurement parameters. This intermediary mechanism automates the configuration management process, reducing the burden on the WTRU's device complexity while enabling fast handover execution

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS9532288B2Optimized serving dual cell change

Publication Date: 2016.12.27 INTERDIGITAL PATENT HOLDINGS INC

AI summary

A method and apparatus for implementing serving cell change in a multi-cell wireless transmit receive unit (WTRU) are disclosed. Serving cell information is received and stored by the WTRU to preconfigure a primary and secondary serving cell of an added cell to an active set. At least one of the preconfigured primary and secondary serving cells are monitored for a handover indication. Serving cell change is to the primary and secondary serving cells us performed using the preconfigured serving cell information upon receipt of a handover indication.