A review on voice over internet protocol on conference call with mobile phone

Conference call services are an essential telecommunication tool in today's business world. In a modernized world, audio conferencing multi-parties can reach out and communicate with people located anywhere in the world. Call conferencing is to stay as one of the most costs operative's means of statement because of the real time interactions, reducing in time and transportable costs and the acceleration of decision making. Conference calls are inherently mobile because anybody can join from their smartphone, either through a steadfast mobile app or by simply ringing the conference line openly. Quality of voice is the major issue in conference calls since factors like low volume, audio noise, audio delays, line noise and feedback, audio echoes etc., have to be detached to improve the voice clarity of a speaker. Voice quality has been made by classy and time overriding. Different atmospheres have different needs, and each conferencing atmosphere has its own acoustical challenge which has to be given attention. This article addresses the issues and challenges for reassuring clear and well-timed communication within contacted phone calls. In this context multi-party conference has been very commonly used now-a-days despite the last mile which could be a VoIP Device, Telephone, WLL based Phone, Cellular Phone (2G, 3G and 4G) etc. With every advanced telecommunication network, problems like popping, static, echo and tapping occurs commonly which results in synchronization of speech processing. It is always difficult for people to process the information when it is less credible. When the voice quality deteriorates, naturally the information being communicated becomes less reliable. One of the critical issues pertaining to communication is poor voice quality when multiple people interact with each other through conference call. Especially in a corporate environment where people operate with heterogeneous communication devices poor voice quality often creates a lousy experience for people involved in the conference call. The situation gets worsened when the number of participants increases and the wide range of connectivity increases due to varied nature of last mile devices and networks involved. Typically, voice signals are represented as continuous signals which can be further decomposed as scaled and shifted delta functions. Various existing methods from literature review are discussed and identified for improving the multi-user voice conference signals, especially the quality of speech in the conference call. Audio quality is essential to both phone and web conference calls, and yet it is the element of conference calls that seems to cause the most trouble and complaints because of poor voice quality. The thesis addresses the problem of quality of voice in conference call using DWT (Discrete Wavelet Transform) techniques and for reverberation and noise reduction using Lynn filter technique. The implementation has been simulated in MATLAB R2013a with simulation results and discussions.