Echo Management in VoIP Conferencing via Mixed Multicast

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Solution Overview

Problem

Current VoIP conferencing systems face challenges in managing echo effectively, leading to increased complexity and CPU bandwidth requirements at participant nodes, as echo cancellation functionality is typically needed at each node.

Innovation Solution

The proposed system employs a master node that mixes and multiplexes digital voice streams, allowing participant nodes to receive mixed or multiplexed streams without their own voice streams, enabling echo cancellation only at the master node and reducing the need for echo cancellation at participant nodes, thus simplifying the system and reducing CPU load.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If echo cancellation functionality is implemented at each participant node, then echo management is effective, but device complexity and CPU bandwidth requirements increase

Engineering Contradiction:

Improveecho management effectivenessVSAvoidparticipant node complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The echo cancellation functionality is extracted from individual participant nodes and centralized at the master node. The master node receives voice streams from all participants, performs echo cancellation on the mixed stream, and returns the cleaned stream to participants. This extraction eliminates the need for complex echo cancellation hardware/software at each participant node while maintaining effective echo management across the conference.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Multiple individual voice streams from different participants are merged into a single mixed stream at the master node. The master node combines these streams, performs centralized echo cancellation on the composite stream, and redistributes the cleaned mixed stream to all participants. This merging approach consolidates processing resources and simplifies participant node architecture.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If echo cancellation is performed at each participant node, then echo is suppressed, but CPU bandwidth consumption increases

Engineering Contradiction:

Improveecho suppressionVSAvoidCPU bandwidth consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent combines multiple individual voice streams into a single mixed stream at the master node before performing echo cancellation. By processing one consolidated stream rather than multiple separate streams at distributed nodes, the total CPU bandwidth consumption is reduced while achieving the same echo suppression effect across all participant connections.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The computationally intensive echo cancellation operation is extracted from resource-constrained participant nodes and relocated to the master node, which has greater processing capacity. This extraction centralizes the CPU-intensive task, preventing bandwidth consumption bottlenecks at participant nodes while maintaining effective echo suppression.

Inventive Principle:

Principle #2Taking out (Extraction)

3Adaptability or versatility

If mixed multicast is used for voice stream distribution, then system scalability improves, but protocol complexity increases

Engineering Contradiction:

Improvesystem scalabilityVSAvoidprotocol complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The master node serves multiple functions: receiving unicast voice streams from all participants, mixing these streams into a composite signal, performing echo cancellation on the mixed stream, and distributing the cleaned mixed stream via multicast to all participants. This multi-functional approach at the master node enables scalable conference calls while keeping participant node protocols simple and uniform.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11606403B2Systems and methods for echo management in conferencing over a network using mixed multicast

Publication Date: 2023.03.14 TYCO FIRE & SECURITY GMBH

AI summary

A system includes participant nodes that unicast a voice stream to a master node and receive a multicast voice stream from the master node. The multicast voice stream may be a mixed voice stream mixing the voice streams of the participants. In this case, each participant performs echo cancellation on the multicast voice stream. Alternatively, the multicast voice stream may be a multiplexed voice stream multiplexing the voice streams of all participants. In this case, each participant de-multiplexes the multicast voice stream and generates a mixed voice stream that does not include that participant. Alternatively, the multicast voice stream received by each participant may be a multiplexed digital voice stream multiplexing multiple mixed streams including one mixed stream that does not include the voice stream of that participant. In this case, each participant de-multiplexes the multicast voice stream to obtain the mixed stream that does not include that participant.