Evolution of voice Communication

From ARPANET(Advanced Reseracha nd Prjects Agency Network) in 1973 by US dept of defence , invention of HTTP in 19196 and finally evoluation of SIP in 2000 and availiability of broadband ethernet services, the telecom landscape has evolved.

As far as infrastructure, services, and contents are concerned, the VoIP industry is witnessing a  migration from POTS / PSTN/  Legacy integrations to  NGN (Next Generation  Network).

NGN is  being implemented globally as a means to change the cost base, agility and service capabilities of telecoms providers. The evolved architecture for the transition is one that provides flexibility to service providers by enabling them to deploy new services on IP based technologies, while leveraging existing services and infrastructure as long as it makes sense.

This post describes the evolution of voice communication in access , transport and  session layers respectively.

1G2G3G4G5G
Year of dev1970-19841980-19991990-20022002-20102010-2015
Launch year1987 by Telstra Australia 1991 in Finland by Elisa1998 pre-commercial launched by NTT DoCoMo in Japan , branded as FOMA.2009 in Stockholm (Ericsson and Nokia Siemens Networks systems) 2019, in South Korea,
TechologyAMPS, NMT , TACSGSMWCDMALTE, WiMAXMIMO , mm Waves
Frequency30 Khz1.8 Ghz1.6 – 2 Ghz2- 8 Ghz3 – 30 Ghz
bandwidth2.4 Kbps14.4 – 50 Kbps ( GPRS)
64 Kbps – 1 Mbps ( EDGE)
144 Kbps – 2 Mbps100 Mbps – 1 Gbps> 1Gbps
upto 35.46 Gbps
Access LayerFDMATDMA/CDMACDMACDMAOFDM/BDMA
Core LayerPSTNPSTNpacketinternetinternet
Compiled by @altanai

Access Layer

We see that the speed enhances considerably with every generation- 1G offerd 2.4 kbps, 2G offered 64 Kbps based on GSM, 3G offered 144 kbps – 2 mbps whereas 4G offers 100 Mbps – 1 Gbps with LTE technology .

It is to be noted that  one of requirements set by IMT-2000 was that speed should be at least 200Kbps to call it as 3G service and 384kbps ( wth stationary speeds of 2Mbps) for a “true” 3G.

ip transformation in access layer
IP transformation in access layer

Note that voice calls in GSM , UMTS and CDMA2000 were circuit switched but with newer technology voice calls became packet switched too and a lot of rereginerring was required.

LTE (Long Term Evolution) is a series of upgrades to existing UMTS technology involving OFDM and MIMO and newer upgrade were called LTE advanced also. Upcoming 5G offers speeds upto 35.46 Gbps.

Transport Layer

ip transformation in transport layer
IP transformation in transport layer

Session Layer

While 2G introduced services like SMS , MMS , internal roaming , conference calls, call hold and billing based on services e.g. charges based on long distance calls and real time billing which were unheard of in 1G , there were challenges in terms of page load speed for interactive websites .

As 3G came into picture, usecases also enhanced with multimedia features siuch as fast web browsing, maps navigation, email, video downloading, picture sharing and other Smartphone technology

ip transformation in session layer
ip transformation in session layer

Read more about IMS ( Ip multimedia System ) IP Multimedia Subsystem ( IMS )

IMS at work from visiting to home location
Access network agnostic

It is noteworthy that SKYPE provided VoIP services ( since 2003) much before mobile phone had 2G/3G ( 2010). In current times with many fantastic options to choose from( whatapp , FB messenger , insta cht , Viber , Hangouts ..) given the high bandwidth with 4G/5G and mych advanced media / signal processing tech , the glocal voip scene is touching 400 mililion subscribers and looks very attractive with 1.5$ billion market .

Enterprise communication systems

On premise private branch exchanges ( PBX ) were the first kind of business telephone systems to which the analog PSTN systems of the company were conneced. These analog circuits were then replaced by digital PBX which provided enhanced features liek screening , voicemails , shared lines.

In the current landscape , the digital PBX of the company is connected to the external telco privider via a SBC or SIP trunking service .

An ompremise LAN based voIP system can be accessed from outside via a VPN on SSL/ IPsec. Although it incures greater CAPEX but ensufe maximum control and ownership of the data . Many time the local laws mandate the server to be hosted with a partuclat geographical area too where an on premise setup and data centre is used.

Enterprise communication shifts from on-premise to SaaS (cloud)

As for remote worksforce and employees working from home (such as during lockdown , pandemics ) it is even more crticial for enterprises to maange inter communication between teams and keep the communication private ie not using piblic messaging platforms , hence the role of cloud based PBX integrated with secure and end to end encrypted telco providers is of prime importance .

To read how a SME can setup their own flexible and scable enterprise comunication system read –

VoIP/ OTT / Telecom Solution startup’s strategy for Building a scalable flexible SIP platform https://telecom.altanai.com/2013/11/21/what-should-a-telecom-solution-startup-do/

With the advent of other disruptive technologies such as free and opensource codecs in browser with WebRTC and well defined framework and standards , voIP definetly looks detsined to expand by leaps and bounds.