Acoustic Echo cancellation inside a Conference Room using Adaptive Algorithms

Abstract: The whole dimension of communications has been changed by the rapid growth of technology. Today people are more interested in hands-free com-mucation, which makes use of loud speaker and high gain microphone, in place of the old modeled wired telephone. The main advantage of wireless system is that, more than one person can participate in conversation while freely moving in the room. The presence of large acoustic coupling between speaker and microphone would produce a loud acoustic echo making the con-versation difficult. The term Acoustic Echo Cancellation (AEC) refers to a process of removing echo from the received signal that contains one or more delayed signals (copies of the original signal). The primary step while cancelling an echo is to identify the transmitted signal which reappears with some delay. Once the echo is identified it is cancelled by subtracting from transmitted signal. Echo cancellation can be done using either echo suppressors or echo cancellers, or in some case both. But suppressors support only half duplex communication leading to the invention of echo cancellers which allows both the speakers to talk at the same time. The main objective of this research is to model a room and cancel the acoustic echo being generated by a speaker and microphone. This dissertation provides a comparison of LMS, NLMS, LLMS and RLS adaptive algorithms in terms of echo return loss enhancement ( ERLE) value and provides the best suitable algorithm for usage in adaptive filters for AEC. AEC is simulated and results are evaluated by using Matlab