WCD State Transition via E-DCH Resource Retention

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Solution Overview

Problem

Existing methods for transitioning a wireless communication device (WCD) from a CELL_FACH state to a CELL_DCH state are not reliable and robust, particularly affecting legacy devices, and can lead to data transmission disruptions and network performance degradation.

Innovation Solution

A method involving a series of configuration messages is used to ensure a WCD retains a common E-DCH resource, including sending a first configuration message for state transition, a second message to obtain or retain the resource, and a third message to force resource retention if the WCD has not transitioned, with the use of a Move Receiving Window super-field and hybrid automatic repeat request negative acknowledgments to manage data transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the WCD waits for the E-DCH transmission continuation back-off timer to expire before releasing the common E-DCH resource, then the WCD ensures complete UL data transmission, but the transition to CELL_DCH state is delayed and network capacity is decreased

Engineering Contradiction:

ImproveUL data transmission completenessVSAvoidstate transition speed

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The network sends a configuration message to the WCD in advance, instructing it to retain the common E-DCH resource even after the back-off timer expires. This preliminary action prevents the WCD from releasing the resource prematurely, ensuring data transmission completeness while maintaining readiness for rapid state transition.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The network monitors the WCD's buffer status and transmission state, then provides feedback through configuration messages to control resource retention. This feedback mechanism allows the network to coordinate resource release timing with the state transition process, resolving the contradiction between reliable transmission and fast transition.

Inventive Principle:

Principle #23Feedback

2Reliability

If the E-DCH transmission continuation back-off timer duration is increased to ensure data transmission completion, then UL data transmission reliability is improved, but network capacity decreases and UL interference increases

Engineering Contradiction:

ImproveUL data transmission completenessVSAvoidnetwork capacity

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

Instead of increasing the timer duration, the network takes preliminary action by sending a configuration message that instructs the WCD to retain the common E-DCH resource. This allows the WCD to maintain transmission capability without being constrained by a prolonged back-off timer, thus preserving network capacity while ensuring transmission reliability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention changes the control parameter from timer duration to resource retention instruction. By modifying how resource retention is controlled (from time-based to command-based), the system achieves reliable transmission without the negative effects of increased timer duration on network capacity and interference.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If the network sends a configuration message to force the WCD to retain the common E-DCH resource, then seamless transition to CELL_DCH state is enabled, but device complexity increases

Engineering Contradiction:

Improvestate transition speedVSAvoidconfiguration message processing

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The configuration message serves multiple functions: it instructs the WCD to retain the common E-DCH resource, confirms the state transition command, and coordinates resource management. This multi-functionality reduces the need for separate signaling messages, thereby limiting the increase in device complexity while achieving seamless state transition.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Quantity of substance

If the WCD releases the common E-DCH resource after the back-off timer expires, then network resources are freed for other WCDs, but the transition to CELL_DCH state cannot be seamless

Engineering Contradiction:

Improvenetwork resource availabilityVSAvoidtransition reliability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The network provides feedback to the WCD through a configuration message that controls resource retention timing. This feedback mechanism allows the WCD to delay resource release until the state transition is complete, ensuring transition reliability while the network maintains awareness of resource status for capacity management.

Inventive Principle:

Principle #23Feedback

Data Source

PatentEP3257322B1Systems and methods for facilitating the transition of a wireless communication device (WCD) from a cell_FACH state to a cell_DCH state

Publication Date: 2019.12.04 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

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AI summary

In one aspect, a method for facilitating the transition of a wireless communication device, WCD, (102) from a CELL_FACH state to a CELL_DCH state is provided. In some embodiments, the method includes determining that the WCD (102) should transition from the CELL_FACH to the CELL_DCH cell state. The method further includes, in response to determining that the WCD should transition from the CELL_FACH to the CELL_DCH cell state, i) sending to the WCD (102) a first configuration message (302) for moving the WCD from the CELL_FACH state to the CELL_DCH state and ii) sending to the WCD a second configuration message (304) for forcing the WCD to obtain a common E-DCH resource or retain a previously obtained common E-DCH resource.