25th September 2008. New Delhi

Factors governing voice quality in VoIP

• Available Bandwidth at caller side – If the caller has poor internet bandwidth then it might affect the voice packets to traverse correctly and essentially affect the voice quality.

• Available bandwidth at carrier side – Call termination also requires adequate internet bandwidth for each call or else it might result in packets loss and other known issues.

• Codecs – The choice of a codec determine as to what is the amount of internet bandwidth that each call will consume. So, for example, if the available internet bandwidth per call is 35 kbps then using G.711 codec would be inefficient choice, as G.711 requires 64 kbps internet bandwidth per call. Whereas, G.723 or G.729 would be good choice.

• Packets Loss – In VoIP, there are 2 parts in which a conversation can be broken:

  • Signaling

  • RTP Packets (also know as Media)

When the caller or callee speaks then the voice travels, from one end to the other through internet, in the form of voice packets. These packets are essentially traversed like data on the internet and each packet is sent in a sequential form. All the voice conversations, in VoIP, happen largely over public internet, hence, it is difficult to control the delivery of voice packets from one end to the other. This results in loss of packets or delay in packets delivery and hence ultimately resulting in voice delay (receiver hear the voice with identifiable delay), loss of voice (receiver is unable to hear something).

• Poor Jitter/Buffer Handling - In order to provide smooth RTP packet flow, Voip Clients (Sometimes server too) manage jitter buffer, in other words client collect packets for a time period, before relaying it. This causes delay in voice but considerably smooth voice flow. Poor jitter-buffer management may result to very long delays.

• Echo – Echo is the phenomenon in which the call receiver or the caller hears own voice being repeated. This occurs because of either faulty microphone and speakers and is enhanced by Amplifiers used in Internet.

• Noise – Poor bandwidth connections, bad quality network wires, transmission leakages collectively result in external noises to be heard along with the primary conversation. The caller and call receiver hear this as noise occurring and thus hampering the conversation quality badly.

Why is good voice quality a challenge in VoIP

• Public Internet for voice traversal

• VoIP being a Distributed & differentiated network

• Lack of affordable & competent solution with capability to handle media effectively

What is the importance of Voice Quality in VoIP

• Today, in global environment, each service provider has access to all the big carriers directly and this means that low rates is not a competitive edge any longer because there is always a lower rate, than what you may offer, available in the market.

• Softswitches plus billing software are also available at very competitive pricing and in very easy to install manner. That means that every one can afford, nearly, similar set of software setup (atleast to support some limited volume of traffic)

• That makes Good Voice Quality as the single most important factor that can be a make or break difference between various competitors in the market.

• Notably, the core function of a tele-conversation is always the voice quality. If there's a problem in this core function then no matter how many add-ons (like low rates, better look & feel) are provided, the service would never succeed.

Possible Solutions to overcome Poor Voice Quality

• Better internet bandwidth connectivity throughout the globe – This is more like a wish than a reality. It would take a lot of years, still, to get the internet bandwidth upgraded.

• One Single unified end-to-end bandwidth channel for all voice conversations on IP (similar to PSTN telephones) – This defeats the benefits that VoIP brings along. The biggest factor contributing to VoIP's rise is the fact that it utilizes the existing internet connectivity prevailing around the world. If one has to setup the point-to-point channels, then it would bring us to back where we were. This is more of a hypothetical situation that a reality.

• Affordable Innovation, at software level, tacking the reasons that result in poor voice quality – An ideal solution, to this present problem, is in the form of a software or set of software that provides a solution to the problems like Packets Delay, Packets Loss, Echo, Noise, Jitter/Buffer etc. Such a software would be effective because it takes care of the root causes and deals with them at software level thus resulting in a stable, echo free, noise free voice conversation through IP.

• What is also important is to make such software really affordable so that it's true power can be realized by all the service providers and the real benefits pass on to the end callers. This would thus culminate in to harnessing the true power of VoIP!
   

About Ascent
Founded in year 2000, we are a New Delhi, India based Softphone development organization that specializes in offering “Private Labeled Secured Voice Quality Enhanced Softphones” to the “Service Providers” globally. Our decade long experience in VoIP & telecom domain enables us to delivery proven, stable, robust & flexible products that fit the varied requirements of our potential customers (read service providers). Our softphone products work on range of operating systems in varied devices: All Windows versions, Symbian operating systems, Windows Mobile operating systems. Our Mobile Softphones run on varied range of handset & operating system vendors: Symbian, Nokia, Windows Mobile, HTC, Samsung, LG, Sony Ericsson etc. Our softphones are highly interoperable with any standard Softswitch, works behind all NAT & firewalls with the use of our Encryption/Decryption technology. Our Encryption/Decryption technology make sure that our softphone works in all the regions where the service providers may block SIP ports to halt the competitive traffic or for any other reason. Encryption/Decryption have been embedded in our both PC Softphone as well as our Mobile Softphone

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