Wireless Conference Phone POD Echo Cancellation
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Solution Overview
Problem
Existing wireless conference phone systems are inadequate for large conference rooms as they lack the ability to effectively manage echo and provide sufficient mobility and flexibility, with previous solutions either being too complex or costly due to the need for sophisticated switching and echo cancellation in both main and satellite units.
Innovation Solution
A wireless conference phone system where each POD unit operates independently, communicating with a base station connected to the outside world telephone network, performing its own echo cancellation, and not with other PODs, allowing for multiple units to connect to the same base station without the need for complex echo cancellation circuitry in the base station.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If wireless conference phones use multiple satellite units connected to a central unit, then coverage area is improved, but device complexity increases due to need for sophisticated echo cancellation across multiple units
Solution Approach 1:
The system divides the conference phone functionality into independent POD units, each capable of autonomous operation. Each POD performs its own echo cancellation independently rather than requiring centralized control across all units. This segmentation allows multiple PODs to cover larger areas while maintaining simple individual device complexity.
Solution Approach 2:
Each POD unit is designed to be self-sufficient with its own echo cancellation circuitry and processing capabilities. The PODs do not rely on the central base station or other PODs for echo cancellation functions. This self-service approach eliminates the need for complex inter-unit coordination and centralized echo management.
2Reliability
If conference phones use full duplex operation with speaker and microphones active simultaneously, then audio quality is improved, but echo problems worsen
Solution Approach 1:
The system uses the speaker output signal itself to generate the echo cancellation reference. By feeding the speaker signal through a model of the acoustic path and subtracting it from the microphone input, the system converts the harmful echo into a useful cancellation signal. This allows full duplex operation with both speaker and microphones active simultaneously without echo problems.
3Device complexity
If wireless conference phones lack satellite units, then device complexity is reduced, but ability to serve large meeting rooms worsens
Solution Approach 1:
Each POD unit is designed as a universal, standalone conference phone that can function independently or in conjunction with other PODs. The same basic unit serves both as a complete conference solution for small rooms and as a scalable component for large rooms. This multi-functionality eliminates the need for different unit types (main vs. satellite) while providing flexible scalability.
Data Source
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AI summary
A wireless conference phone system has a base station to couple at least one conference unit to a telephone network, such as the public switched telephone network (PSTN) or a digital telephone network such as a voice over internet protocol (VoIP) network. Each conference unit performs echo cancellation of the audio signal received from a remote location allowing a simplified base station implementation.