Packet Protection for VoIP Signal Reconstruction
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Solution Overview
Problem
Existing methods for managing packet switched networks, such as VoIP, face challenges in reconstructing encoded signals when packets are lost, leading to signal deterioration and bandwidth inefficiencies, particularly in cases where recalculating filter memory values is not feasible.
Innovation Solution
A method that identifies essential frames in a communication signal and adds protecting information to packets preceding these frames, allowing for better decoding and synthesis of subsequent frames, even if the essential frame is lost, thereby reducing signal deterioration and improving synchronization between encoder and decoder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If protecting information is added to all packets to prevent frame loss deterioration, then signal quality is improved, but bandwidth consumption increases
Solution Approach 1:
The patent applies local quality by selectively adding protecting information only to specific packets that carry essential frames, rather than uniformly protecting all packets. Essential frames are identified as those where loss would cause substantial deterioration in proceeding frames (e.g., frames containing transitions from unvoiced to voiced signals). This selective protection approach maintains signal quality for critical frames while avoiding unnecessary bandwidth consumption for non-essential frames.
Solution Approach 2:
The patent implements partial action by providing protecting information for only a subset of packets rather than all packets. The protecting information is strategically added to packets containing essential frames that have high impact on signal quality, achieving adequate protection with partial coverage. This avoids the excessive action of protecting every packet, thereby reducing overall bandwidth consumption while maintaining acceptable signal quality.
2Reliability
If replicas of important frames are carried in subsequent packets, then packet loss resistance is improved, but transmission delay increases
Solution Approach 1:
The patent applies preliminary action by adding protecting information to packets that precede the essential frames rather than placing replicas in subsequent packets. The protecting information is embedded in advance in the preceding packet, allowing the receiver to reconstruct lost essential frames without waiting for subsequent packets. This eliminates the transmission delay that would result from carrying replicas in later packets while still providing packet loss resistance.
3Reliability
If XOR operations are performed on consecutive packets, then error protection is improved, but bandwidth efficiency deteriorates
Solution Approach 1:
The patent applies local quality by selectively applying XOR operations or other protecting information only to specific packets containing essential frames, rather than performing XOR operations on all consecutive packets. This selective approach provides error protection where it is most needed while avoiding the bandwidth inefficiency of universally applying protection mechanisms to all packets.
Data Source
AI summary
A method and devices using that method are provided for reconstructing an encoded signal conveyed along a communication path in a packet switched network. The method comprises the steps of providing a communication signal that has been encoded into a plurality of frames; determining which of the plurality of frames is an essential frame, which loss would cause a relatively substantial deterioration in the quality of at least one proceeding frame upon decoding that at least one proceeding frame; packaging the plurality of frames into a plurality of packets, and identifying which of the packets comprise at least one essential frame; adding protecting information to at least one packet which proceeds a packet identified as a packet carrying at least one essential frame.