Hybrid RTP Payload Switching for Legacy Codec Interoperability

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Solution Overview

Problem

Existing speech/audio codecs face interoperability issues when introducing new codecs into legacy systems, leading to increased network costs and undesirable speech quality degradations, particularly in limited resource applications and scenarios like multi-party conferencing and hand-over scenarios, where traditional transcoding and capability exchange methods are not feasible.

Innovation Solution

A multi-mode speech/audio codec that dynamically decides between header-less and header-full RTP payload formats based on codec mode and bit rate, using a set of unique packet sizes to avoid ambiguities and include necessary signaling information, allowing efficient transmission and decoding while maintaining compatibility with legacy equipment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a new speech codec is introduced into a legacy communication system, then service quality is improved, but interoperability problems occur between new and legacy equipment

Engineering Contradiction:
Improveservice qualityVSAvoidinteroperability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The payload format dynamically adapts between header-less and header-full modes based on the codec mode being transmitted. The format includes a mode indication field that allows the receiver to automatically adjust its processing mode, enabling seamless interoperability between new EVS codecs and legacy AMR-WB equipment without requiring static configuration or capability exchange procedures

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent introduces an intermediary mechanism - the mode indication field within the payload format - that mediates between new and legacy codecs. This field acts as a signal that allows legacy equipment to correctly interpret packets from new codecs and vice versa, eliminating the need for transcoders or capability exchange while maintaining both service quality improvement and interoperability

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If transcoders are provisioned in media gateways to translate between new and old coding formats, then interoperability is achieved, but network investment and maintenance costs increase

Engineering Contradiction:
ImproveinteroperabilityVSAvoidnetwork investment and maintenance costs
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts the interoperability function from separate transcoder devices and integrates it directly into the payload format structure. By embedding mode indication fields and using conditional header inclusion, the system achieves codec translation capability without requiring physical transcoder infrastructure, thereby eliminating additional network investment and maintenance costs while maintaining interoperability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The payload format enables self-service interoperability by including all necessary mode indication information directly within the packet structure. The format allows receiving equipment to automatically determine the appropriate decoding mode based on the included indicators, eliminating the need for external transcoder assistance and reducing network infrastructure requirements

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If capability exchange between terminals is implemented prior to call, then interoperability is ensured, but the method is not always possible in scenarios like multi-party conferencing and hand-over scenarios

Engineering Contradiction:
ImproveinteroperabilityVSAvoidoperational flexibility
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent implements preliminary action by embedding mode indication information directly in the payload format structure before transmission occurs. This pre-inclusion of codec mode indicators eliminates the need for runtime capability exchange procedures, enabling immediate interoperability in dynamic scenarios such as multi-party conferencing and hand-over situations where SDP negotiation is not feasible

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The payload format dynamically adapts to different operational scenarios by including mode indication fields that allow receiving equipment to automatically adjust processing modes in real-time. This dynamic capability enables seamless operation in diverse scenarios including multi-party conferencing, hand-over situations, and voice messaging without requiring pre-call capability exchange or terminal-specific configurations

Inventive Principle:
Principle #15Dynamics

4Adaptability or versatility

If terminal implementation supports complete set of new and legacy codecs, then interoperability is achieved, but implementation and technology licensing costs increase

Engineering Contradiction:
ImproveinteroperabilityVSAvoidimplementation and technology licensing costs
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements universality by designing a single payload format structure that can handle both new EVS codec modes and legacy AMR-WB modes. The format includes mode indication fields and conditional header elements that enable one terminal implementation to universally support multiple codec types without requiring separate processing paths, thereby reducing implementation complexity and technology licensing costs while maintaining complete interoperability

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

Data Source

PatentEP3917112B1Hybrid RTP payload format
Publication Date: 2022.10.05 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3917112B1 patent drawingFigure 1~3
  • EP3917112B1 patent drawingFigure 2
  • EP3917112B1 patent drawingFigure 4~5

AI summary

A multi-mode speech or audio codec is provided. The multi-mode speech or audio codec comprises means for formatting a payload for transmission of multi-mode speech codec data or multi-mode audio codec data. Said means are configured to decide based on a codec mode and a bit rate whether a header-less or a header-full payload format is used. If the header-full payload format with a payload header is used the payload header comprises signaling information, wherein the signaling information is associated with at least one of: a codec mode identification, a bit rate, a mode adaptation, a codec mode request, an audio bandwidth, a codec internal mode and frame aggregation. Said means being configured to packetize an RTP payload data with or without the payload header depending on the decision.