In-band signaling for dynamic codec switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Telecommunications networks face challenges in maintaining voice signal quality due to transcoding, which introduces latency and degradation, especially when using incompatible codecs, and the infrastructure costs and complexity of upgrading to support advanced codecs like EVRC-WB are barriers to adoption.
Innovation Solution
In-band signaling is used to dynamically switch between codecs, such as EVRC-B and EVRC-WB, within established calls, allowing compatible codecs to be used without infrastructure upgrades, ensuring transcoding-free operation and maintaining quality for legacy users by probing the capabilities of connected stations and switching between narrowband and wideband modes as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If advanced codecs like EVRC-WB are deployed to improve voice signal quality and eliminate transcoding, then voice signal quality and latency are improved, but infrastructure upgrade cost and device complexity increase
Solution Approach 1:
The system dynamically switches between narrowband and wideband codecs based on real-time capability detection through in-band signaling. Stations probe each other's codec capabilities during calls and adaptively select the appropriate codec mode, enabling advanced wideband operation when both endpoints support it while automatically falling back to narrowband when encountering legacy devices, thus eliminating the need for universal infrastructure upgrades.
Solution Approach 2:
The invention changes the operational parameters of the codec system by introducing in-band signaling mechanisms that allow stations to negotiate and switch between different codec modes (narrowband EVRC-B and wideband EVRC-WB) during call establishment and execution. This parameter switching enables advanced functionality when conditions permit while maintaining compatibility with legacy systems.
2Adaptability or versatility
If in-band signaling is used to dynamically switch codecs between stations, then adaptability and compatibility are improved, but device complexity and processing overhead increase
Solution Approach 1:
The system implements self-service capability detection where stations autonomously probe each other's codec capabilities through in-band signaling during calls. Each station independently determines the appropriate codec mode by analyzing responses from the remote station, eliminating the need for complex centralized negotiation protocols or additional infrastructure elements, thus achieving high adaptability with minimal processing overhead.
3Reliability
If transcoding is avoided by using compatible codecs, then voice signal quality is improved, but device complexity increases due to multiple codec support requirements
Solution Approach 1:
The invention extracts the codec capability information exchange from the traditional call setup signaling and embeds it within the voice traffic itself through in-band signaling. This separation allows stations to support multiple codecs (both narrowband and wideband) without requiring complex pre-call negotiation protocols, as the capability detection happens transparently during the call using the voice channel itself, thus maintaining voice quality while managing device complexity.
Data Source
AI summary
After a call is established between two stations using a codec that has been negotiated during call setup, in-band signaling may be used between the two stations to change the codec that is to be used. The in-band signals are indicative that the station that is transmitting the in-band signals can operate with a second codec and are used to probe whether the receiving station can also operate with that second codec. If the receiving station detects and reacts to the in-band signals, then both stations change to communicate with the second codec. The second codec has compatible packet sizes of the deployed (originally negotiated) codec without any need of infrastructure upgrade and/or quality compromise to legacy phone users (i.e., stations that cannot operate with the second codec).