RFCI Handling in HNB Relocation for Transcoder-Free Voice

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Solution Overview

Problem

In mobile communication systems with Home Node-B (HNB) and Home Node-Gateway (HNB-GW) configurations, the mismatch of Radio Access Bearer sub-flow Combination Indicator (RFCI) information between movement-origin and movement-destination base stations hinders transcoder-free operation during intra-HNB-GW relocation, leading to disrupted voice communication.

Innovation Solution

The system sets RFCI information in advance for both movement-origin and movement-destination base stations and uses a higher-order apparatus or gateway apparatus to transmit and convert this information without an Iu User Plane Initialization procedure, ensuring consistent data frame structures and maintaining transcoder-free operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If RFCI information is not handed over between movement-origin and movement-destination base stations during relocation, then the Iu User Plane Initialization procedure is avoided, but RFCI information mismatch occurs and transcoder-free operation cannot be maintained

Engineering Contradiction:
Improverelocation processing timeVSAvoidtranscoder-free operation reliability
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The patent applies preliminary action by having the movement-origin base station transmit its RFCI information to the higher-order apparatus before relocation occurs. The higher-order apparatus then proactively transmits this pre-acquired RFCI information to the movement-destination base station, ensuring that RFCI information is available before the relocation completes, thus maintaining transcoder-free operation without waiting for post-relocation initialization.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces a higher-order apparatus as an intermediary between the movement-origin base station and movement-destination base station. This intermediary receives RFCI information from the movement-origin base station and forwards it to the movement-destination base station, enabling RFCI information handover without requiring direct communication between the base stations or triggering Iu User Plane Initialization.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If RFCI information is handed over between base stations during relocation, then transcoder-free operation is maintained, but additional signaling procedures are required

Engineering Contradiction:
Improvetranscoder-free operation reliabilityVSAvoidsignaling procedure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies universality by utilizing the existing RANAP Relocation Required and Relocation Request messages for dual purposes: both the relocation procedure itself and the RFCI information handover. The higher-order apparatus incorporates RFCI information transmission within these existing message structures, allowing one mechanism to serve multiple functions without adding separate dedicated signaling procedures.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent applies copying by having the higher-order apparatus copy the RFCI information from the movement-origin base station and replicate it in the relocation signaling messages sent to the movement-destination base station. This copying mechanism ensures accurate transmission of RFCI information without requiring the movement-destination base station to regenerate or re-derive the information.

Inventive Principle:
Principle #26Copying

3Productivity

If RFCI information mismatch occurs between base stations, then voice communication can proceed with transcoder-free operation, but data frame structure consistency is compromised

Engineering Contradiction:
Improvevoice communication continuityVSAvoiddata frame structure consistency
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The patent applies feedback by having the movement-destination base station receive and process RFCI information from the movement-origin base station through the higher-order apparatus. This feedback mechanism ensures that the movement-destination base station is informed about the expected data frame structure, allowing it to properly interpret and process incoming voice data without requiring transcoder intervention.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2466988B1Mobile communication system, base station, higher-order apparatus, communication method, and program
Publication Date: 2020.02.19 NEC CORP
  • EP2466988B1 patent drawingFigure 1
  • EP2466988B1 patent drawingFigure 2
  • EP2466988B1 patent drawingFigure 3

AI summary

A mobile communication system including: a terminal, a movement-origin base station to which the terminal connects before movement of the terminal; a movement-destination base station to which the terminal connects after movement of the terminal; and a higher-order apparatus that has the movement-origin base station and the movement-destination base station under its control. Control information for voice encoding is set in advance in the movement-origin base station and the movement-destination base station, the movement-origin base station includes the control information of its own station in a first message and transmits the first message to the higher-order apparatus, and the higher-order apparatus includes the control information of the movement-origin base station in a second message and transmits the second message to the movement-destination base station.