Vocoder Handoff State Memory Transcoder
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Handoffs between different types of voice encoders (vocoders) in communication systems are complicated by incompatible architectures, bit streams, and algorithmic delays, leading to potential communication delays or loss due to misaligned output signals.
Innovation Solution
A method involving a state memory transcoder that translates the state memory of one vocoder to another, time-delaying the state memory to match the algorithmic delay of the second vocoder, and using a fadeover switch to smoothly transition between vocoders, ensuring seamless handoffs by aligning and encoding signals according to the second vocoder's parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If handoff is performed between different types of vocoders with incompatible architectures, then communication continuity is maintained, but signal alignment and communication quality deteriorate due to incompatible bit streams, different frame sizes, and different algorithmic delays
Solution Approach 1:
A transcoding module is introduced as an intermediary component between the first and second vocoders. This module receives output from the first vocoder, performs transcoding to adapt to the second vocoder's format requirements, and outputs to the second vocoder. The intermediary handles bit stream conversion, frame size adaptation, and algorithmic delay compensation, enabling seamless handoff while maintaining signal alignment between incompatible vocoder architectures.
2Adaptability or versatility
If handoff is performed between vocoders with different algorithmic delays, then network flexibility and adaptability are improved, but output signal alignment deteriorates causing perceptible gaps or delays
Solution Approach 1:
The transcoding module performs preliminary actions by calculating the algorithmic delay difference between the first and second vocoders before the handoff occurs. It pre-adjusts the timing of bit streams and prepares appropriate buffering or delay compensation mechanisms in advance. This preliminary timing alignment ensures that when the handoff occurs, the output signals from both vocoders are properly synchronized, preventing perceptible gaps or delays while maintaining network flexibility to use different vocoder types.
Data Source
AI summary
Provided are methods and systems of managing handoffs in a wireless communication system having different types of vocoders. Some embodiments include translating state memory of a first vocoder to a second vocoder using a state memory transcoder. The state memory may be delayed to align differences in algorithmic delays between the first vocoder and the second vocoder. In one embodiment, a speech signal may be decoded from the first vocoder, delayed, and encoded to the second vocoder. Furthermore, for a period of time during and/or adjacent to the handoff, the first vocoder may output with decreasing amplitude while the second vocoder outputs with increasing amplitude. Such techniques may be used alone or in combination.