MBMS Continuity via MBSFN Area Matching

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Solution Overview

Problem

Current multimedia broadcast multicast service (MBMS) technologies face challenges in maintaining service continuity for User Equipment (UE) in Radio Resource Controller (RRC) connected and idle modes, particularly in handover scenarios where the target cell may not belong to the same Multicast/Broadcast Single Frequency Network (MBSFN) area, leading to potential service disruptions and quality issues.

Innovation Solution

The proposed solution involves identifying and selecting a target cell within the same MBSFN area or with matching Multicast Group Identifiers (TMGI) for UE in RRC connected and idle modes, using mechanisms like measurement reports, MBMS query procedures, and assistance information to ensure seamless MBMS service continuity, even if the target cell is not synchronized with the serving cell.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If handover is performed to a target cell outside the same MBSFN area, then mobility and network flexibility are improved, but MBMS service continuity is degraded

Engineering Contradiction:

ImprovemobilityVSAvoidMBMS service continuity

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The network performs preliminary actions by identifying and pre-configuring target cells that can provide MBMS service continuity before handover is triggered. The source eNB retrieves MBMS service information from the target eNB in advance and prepares handover commands that include necessary MBMS configuration parameters, ensuring that the UE can maintain MBMS reception during and after handover.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The source eNB acts as an intermediary between the UE and target eNB during handover. It retrieves MBMS service information from the target eNB, processes this information to determine appropriate MBMS configuration parameters, and incorporates these parameters into the handover command sent to the UE, thereby mediating the complex interaction between mobility management and MBMS service continuity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If handover is performed to a target cell within the same MBSFN area, then MBMS service continuity is improved, but network flexibility and mobility options are degraded

Engineering Contradiction:

ImproveMBMS service continuityVSAvoidnetwork flexibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The invention changes the parameters included in handover commands from traditional radio resource parameters to include MBMS-specific parameters such as MBSFN area identifier, MBMS service identifier, and MBMS configuration parameters. This allows the handover process to adapt to MBMS service requirements while maintaining network flexibility through configurable parameter sets.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If MBMS service information is retrieved and processed during handover, then MBMS service continuity is improved, but handover signaling complexity and processing time are degraded

Engineering Contradiction:

ImproveMBMS service continuityVSAvoidhandover signaling complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The handover process is segmented into distinct phases: MBMS service information retrieval phase, processing and determination phase, and command transmission phase. This segmentation allows each phase to be optimized independently, with MBMS information retrieved in parallel with other handover preparations, reducing overall complexity and processing time.

Inventive Principle:

Principle #1Segmentation

4Reliability

If MBMS configuration parameters are included in handover commands, then MBMS service continuity is improved, but message size and signaling overhead are degraded

Engineering Contradiction:

ImproveMBMS service continuityVSAvoidsignaling overhead

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The handover command message structure is designed to be universal and multi-functional, incorporating both traditional radio resource handover parameters and MBMS-specific parameters within a unified framework. This allows the same message to serve multiple purposes: radio resource allocation, MBMS service continuity maintenance, and configuration parameter transmission, thereby reducing overall signaling overhead.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentEP2850876B1Maintaining MBMS continuity

Publication Date: 2022.11.02 BLACKBERRY LTD

Figure 1A~1B
Figure 1C~2
Figure 3

AI summary

Systems, apparatuses, and computer implemented methods may be directed to identifying that a user equipment (UE) is near a cell edge of the source base station, the UE receiving or requesting a multimedia broadcast multicast service (MBMS). A target base station can be identified based, at least in part, on the MBMS received at or requested by the UE. The target base station can be provided to the UE, for example, by providing an indication to the UE of a target base station from which to receive services. The target base station may be acquired through a handover procedure (RRC connected mode), or through a cell selection procedure (RRC idle mode). The target base station can be identified based on a multimedia broadcast single frequency network area identifier (MBSFN ArealD) for a synchronized MBMS continuity across network cells or by a temporary multicast group identity (TMGI) for asynchronous MBMS continuity across network cells.