Core Network Node Time Coordinated Cells eDRX Paging

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Solution Overview

Problem

The lack of time coordination among cells in wireless communication networks leads to issues such as wireless devices missing paging opportunities or receiving duplicate pages due to mobility, and temporary identifiers becoming invalid, resulting in paging failures or bandwidth waste.

Innovation Solution

Implementing a system where the Core Network node (e.g., SGSN) and Radio Access Network nodes synchronize paging occasions across multiple cells, ensuring each paging event occurs approximately at the same time, using modified RAU and paging procedures to calculate and maintain the time remaining until the next paging opportunity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cells are not time coordinated, then wireless devices can experience missed paging opportunities or duplicate pages due to mobility, but implementing time coordination requires modified RAU and paging procedures and increased network complexity

Engineering Contradiction:
Improvepaging reliabilityVSAvoidnetwork procedure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The network performs preliminary time coordination calculations during RAU acceptance, determining the time remaining until the next paging opportunity in advance. This allows the network to proactively adjust paging timing and send dummy paging requests to synchronize paging occasions across cells before mobility issues arise, rather than reacting to missed pages or duplicate pages after they occur.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary mechanism where the core network node (SGSN) acts as a coordinator between RAN nodes and wireless devices. The SGSN calculates time remaining until next paging opportunities and communicates this information to RAN nodes, which then adjust their paging transmissions accordingly. This intermediary coordination layer resolves timing conflicts without requiring direct complex interactions between all network elements.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If paging occasions are not synchronized across cells, then temporary identifiers may become invalid due to routing area updates, but synchronizing paging occasions requires calculating and maintaining time remaining information

Engineering Contradiction:
Improveidentifier validityVSAvoidinformation management overhead
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The system performs preliminary calculation of time remaining until the next paging opportunity when processing RAU acceptance. By determining this timing information in advance, the network can proactively manage identifier validity periods and coordinate paging transmissions before temporary identifiers become invalid, reducing the need for frequent re-coordination and information updates.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback mechanism where the time remaining until next paging opportunity is calculated and communicated back to RAN nodes. This feedback loop allows the network to continuously monitor and adjust paging timing based on current system state, ensuring temporary identifiers remain valid while minimizing unnecessary information exchanges through intelligent timing of updates.

Inventive Principle:
Principle #23Feedback

3Duration of action of moving object

If wireless devices use extended discontinuous receive (eDRX) cycles, then battery life is extended, but paging reliability decreases due to longer intervals between paging opportunities

Engineering Contradiction:
Improvebattery lifeVSAvoidpaging reliability
Core Design Contradiction:
Duration of action of moving objectVSReliability

Solution Approach 1:

The network performs preliminary calculation of time remaining until the next paging opportunity based on eDRX cycle timing. By knowing in advance when the device will wake up from its extended sleep period, the network can proactively prepare and transmit paging messages at the optimal moment, ensuring paging reliability is maintained despite the long intervals between paging opportunities enabled by eDRX.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The core network node acts as an intermediary that bridges the long eDRX cycle intervals with the need for reliable paging. The SGSN calculates timing information and coordinates with RAN nodes to ensure paging messages are transmitted at the precise moment the device becomes reachable, effectively mediating between the device's power-saving strategy and the network's need to deliver messages reliably.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3554153B1Core network node and method--time coordinated cells for extended discontinuous receive (EDRX)
Publication Date: 2020.04.22 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3554153B1 patent drawingFigure 1
  • EP3554153B1 patent drawingFigure 2
  • EP3554153B1 patent drawingFigure 3~4

AI summary

A core network node (e.g., Serving GPRS Support Node (SGSN)), a radio access network node (e.g., Base Station Subsystem), and various methods are described herein for realizing time coordinated cells and maintaining a reliability of paging a wireless device (e.g., Machine Type Communications (MTC) device, mobile station).