Significance of Vocoders in Mobile Communication

Abstract

Signal Processing finds its applications in many fields of engineering like Communications, Multimedia processing like audio, speech, video compression. It is the constant endeavor in compression techniques to retain highest quality of media through lowest bits so that communication band width utilization can be maximized. The most basic form of end user communication in the mobile industry has been voice calls. Speech signals captured at the microphone are sampled at 8 or 16 KHz and using 16 bits per sample presents 128 KHz of information. Transmitting all of it is very inefficient usage of the communication channel. There are multiple ways to encode the speech input at lower bit rates using Source Coding and Waveform coding techniques. This paper is scoped to practically simulate some of the basic and advanced signal processing concepts and apply them to the speech signal processing domain to minimize the vocoders packet exchange bit rate. Existing techniques are studied and a new schema is proposed which reduce the vocoders packet exchange bit rate further.