Cabin car communication system to improve communications inside a car

This paper presents a cabin car communication system (CCCS) to improve the communication among passengers inside a car. Noise, distance between speakers and many other factors make difficult to maintain a conversation inside a car. The CCCS picks up the speech of each passenger, amplifies it, and uses the car loudspeaker system to return it into the cabin. Two problems arise when designing a CCCS; the electro-acoustic coupling between loudspeakers and microphones, and the amplification of the inside car noise. As a result of the first problem, the system may become unstable. To maintain the stability of the system, the CCCS makes use of a robust acoustic echo cancellation scheme based on system identification and a Wiener echo suppressor. Using a noise reduction system based on Wiener filtering reduces second problem, noise amplification. Experimental results showing the performance of the system in terms of acoustic echo and noise reduction and speech reinforce are presented. A system with 2-input/2-output channels has been built on a DSP board for medium size cars and minivan vehicles.