IMS MBMS File Repair Through Scalable HTTP Servers

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Solution Overview

Problem

MBMS-based transmissions lack data recovery mechanisms like ARQ and HARQ, leading to data loss or corruption, and current file-repair architectures rely on dedicated servers that are costly and do not scale well with large deployments.

Innovation Solution

Utilize conventional HTTP web servers for file-repair requests, leveraging existing scalable infrastructure to handle MBMS file repairs through AL-FEC schemes, allowing UEs to request and receive redundant symbols over unicast bearers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If dedicated file-repair servers are used for MBMS file repair, then file repair reliability is improved, but system complexity and deployment cost increase

Engineering Contradiction:
Improvefile repair reliabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies universality by enabling conventional HTTP web servers to perform dual functions: their original web serving role and new file-repair functionality. This allows existing infrastructure to handle MBMS file repairs without requiring specialized dedicated servers, thereby maintaining reliability while reducing system complexity and deployment cost.

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

Solution Approach 2:

The patent implements self-service by allowing user equipment to autonomously initiate file repair requests directly to HTTP servers using standard HTTP protocols. The system enables itself to repair files without requiring complex dedicated repair server infrastructure, as regular web servers naturally handle these requests through their existing HTTP capabilities.

Inventive Principle:
Principle #25Self-service

2Reliability

If dedicated file-repair servers are deployed, then file repair capability is improved, but scalability deteriorates

Engineering Contradiction:
Improvefile repair capabilityVSAvoidscalability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

By making HTTP servers universal platforms that handle both web content delivery and file repair operations, the system achieves scalability. Existing distributed web server infrastructure can be leveraged across the network, allowing the file repair service to scale automatically with the deployment without requiring additional specialized server infrastructure.

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

Solution Approach 2:

The patent applies copying by utilizing the existing widespread deployment of conventional HTTP web servers throughout the network. Instead of copying or deploying specialized file-repair server software, the system copies the capability to use standard HTTP protocols across existing web server instances, enabling scalable file repair service across multiple locations without additional infrastructure complexity.

Inventive Principle:
Principle #26Copying

3Device complexity

If MBMS transmissions use traditional channel coding only, then system simplicity is maintained, but data recovery capability deteriorates

Engineering Contradiction:
Improvesystem simplicityVSAvoiddata recovery capability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces an intermediary layer of application-layer forward error correction (AL-FEC) codes that work in conjunction with traditional channel coding. This intermediary AL-FEC layer provides enhanced data recovery capability for MBMS transmissions without replacing the existing channel coding infrastructure, thereby maintaining system simplicity while improving reliability through the additional protective layer.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3726864B1IP multimedia subsystem and method for MBMS file repair using HTTP servers
Publication Date: 2025.07.02 APPLE INC
  • EP3726864B1 patent drawingFigure 1
  • EP3726864B1 patent drawingFigure 2
  • EP3726864B1 patent drawingFigure 3

AI summary

Disclosed in some examples is a method of media repair in an Internet Protocol Multimedia Subsystem (IMS) based network, the method includes communicating with an IMS network component using a Session Initiation Protocol (SIP) to setup a download session with a Broadcast-Multicast Service Center (BMSC) over a Multi Media Broadcast Multicast Service (MBMS) bearer; responsive to determining that one or more encoding symbols of media downloaded using the established MBMS bearer cannot be decoded: requesting a file repair procedure from the IMS network component using a SIP re-invite request, the SIP re-invite request including an address of an HyperText Transfer Protocol (HTTP) repair server indicated by the IMS network component during the MBMS bearer setup; responsive to receiving a SIP acknowledgement indicating that the request was successful, requesting an HTTP connection with the HTTP server to re-download the one or more encoding symbols of the media that could not be decoded; and receiving the one or more encoding symbols from the HTTP server.