Broadband Lost Frame Concealment Using Band-Specific Signal Recovery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing lost frame concealment technologies are inadequate for broadband signals and fail to meet the requirements for high-quality calls, as they are primarily designed for 8 kHz sampling narrowband signals and introduce additional delays.
Innovation Solution
A device and method that include a lost frame detector, decoding module, low band delay module, low band signal recovering module, high band lost frame concealment module, and Quadrature Mirror Filter (QMF) synthesis filter to detect and recover lost voice frames, generating a previous frame voice signal without introducing additional delay, thereby enhancing low and high band signal concealment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing lost frame concealment algorithms are used, then narrowband signal concealment is achieved, but broadband signal quality deteriorates
Solution Approach 1:
The patent divides the broadband signal into low-band and high-band components, applying different concealment strategies to each band. The low-band signal uses traditional concealment methods while the high-band signal uses spectral transformation techniques, thereby achieving effective concealment across the entire broadband spectrum rather than being limited to narrowband signals.
Solution Approach 2:
The patent transforms the high-band lost frame concealment problem from the time domain to the frequency domain using spectral transformation. By operating in the frequency domain and then transforming back, the system achieves effective concealment for broadband signals that cannot be handled by traditional time-domain narrowband algorithms.
2Device complexity
If traditional lost frame concealment methods are applied, then processing simplicity is maintained, but additional delays are introduced
Solution Approach 1:
The patent performs spectral transformation and concealment operations on the high-band signal in advance, before the lost frame occurs. By preparing the spectral components and concealment data beforehand, the system can rapidly reconstruct lost frames without introducing significant additional delay, thus balancing processing complexity with time efficiency.
3Reliability
If broadband signal processing is implemented, then high-quality call requirements are met, but processing complexity increases
Solution Approach 1:
The patent applies different processing complexities to different frequency bands based on their importance. The low-band signal, which contains fundamental speech information, receives simpler concealment processing, while the high-band signal, which contains spectral detail, receives more sophisticated spectral transformation processing. This localized approach achieves high overall quality without uniformly increasing complexity across the entire system.
Data Source
AI summary
A device for lost frame concealment comprises: a lost frame detector for detecting whether a voice frame is lost, a decoding module for decoding the current voice frame, a low band delay module for delaying the low band signal, a low band signal recovering module for recovering the lost low band signal, a high band lost frame concealment module for processing the lost frame concealment for the high band signal, and a QMF synthesis filter for synthetically filtering the low band signal and the high band signal. The invention makes full use of the delay of the coding/decoding device itself, enhances the effect of lost frame concealment for the low band signal and the high band signal, and introduces no nearby delay during the process of lost frame concealment.