SGSN Handover Context Detection for Radio Resource Optimization

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Solution Overview

Problem

In radio telecommunications networks, handover of packet-switched connections results in non-optimal resource utilization due to the deletion of inactive packet flow contexts by the packet control unit, leading to unnecessary resource allocation during handover processes.

Innovation Solution

A method is introduced where the Serving GPRS Support Node (SGSN) detects and communicates the number of active packet flow contexts to the target packet control unit during handover, ensuring only active contexts are re-established, thereby conserving resources by avoiding the setup of inactive ones.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the PCU deletes inactive PFCs to conserve radio resources, then resource utilization is improved, but the SGSN lacks knowledge of active PFCs leading to non-optimal resource allocation during handover

Engineering Contradiction:
Improveradio resource utilizationVSAvoidPFC status information
Core Design Contradiction:
Loss of energyVSLoss of information

Solution Approach 1:

The source PCU sends feedback information to the SGSN about the status of PFCs (active or deleted) through the handover message. This feedback mechanism allows the SGSN to obtain accurate PFC status information without the PCU maintaining continuous knowledge of all PFC states, thus conserving radio resources while enabling optimal handover resource allocation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The SGSN acts as an intermediary between the source PCU and target PCU. The source PCU provides PFC status information to the SGSN, which then uses this information to instruct the target PCU on which PFCs to set up. This intermediary approach allows resource optimization at the PCU level while maintaining accurate information flow through the SGSN.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the SGSN requests PFC setup for all PDP contexts during handover, then service continuity is ensured, but radio resources are wasted on inactive PFCs

Engineering Contradiction:
Improveservice continuityVSAvoidradio resource allocation
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

Instead of requesting setup for all PDP contexts (excessive action), the SGSN uses the PFC status information from the source PCU to request setup only for active PFCs (partial action). This selective approach maintains service continuity for active connections while avoiding unnecessary resource allocation for inactive PFCs that would not be used anyway.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The handover message includes a parameter indicating PFC status (active or deleted). The SGSN uses this parameter to dynamically adjust which PFCs are requested for setup in the target PCU, changing the resource allocation parameters based on actual usage status rather than using a fixed approach for all PDP contexts.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the PCU maintains knowledge of all PFCs, then accurate resource management is achieved, but system complexity increases

Engineering Contradiction:
Improveresource management accuracyVSAvoidPCU system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system divides the knowledge burden by segmenting which entity maintains which information. The PCU maintains only the actual PFC status (simple local state), while the SGSN receives this information and makes the handover decisions. This segmentation allows the PCU to remain simple while the overall system achieves accurate resource management through information sharing.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2016795B1Packet data support node and method of activating packet flow contexts during handover
Publication Date: 2016.08.17 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP2016795B1 patent drawingFigure 1
  • EP2016795B1 patent drawingFigure 2~3
  • EP2016795B1 patent drawingFigure 4~5

AI summary

A method and packet data support node (204) in a radio telecommunications network supporting packet data communication between a packet data network and a mobile terminal (203) in radio communication with a first packet control unit (201 ).The packet data support node receives a message from the mobile terminal requesting handover to a second packet control unit (202). A packet flow context detector in the packet data support node (204) detects the number of packet flow contexts currently active in the first packet control unit (201 ) for supporting the packet data connection. The detector sends a message during handover to the second packet control unit (202) indicating the number of active packet flow contexts. The message is used for activation of a corresponding number of packet flow contexts in the second packet control unit.