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What is VoLTE or Voice over LTE?

What is VoLTE or Voice over LTE?

VoLTE has taken the world by storm, since its inception. It is honestly not surprising given that, VoLTE has three times more the capacity of older technologies like 3G  UMTS and six times more than 2G GSM. The following numbers will help us understand better the magnitude of the rise of VoLTE – according to Global Mobile Suppliers Association, as of February 2019, globally there are 253 operators who have investments in VoLTE in 113 countries, this includes 184 operators who have already launched VoLTE-HD voice service in 87 countries in a commercial capacity. To put the numbers into perspective, according to Global Mobile Suppliers Association the number of operators who have invested in VoLTE went up from 137 operators in 65 countries in just one year from February 2018. As of August 2019, the numbers had significantly risen, there were 262 operators with investments in VoLTE spread in a total of 120 countries and out of those, 194 operators have launched VoLTE-HD enabled voice services in 91 countries.

The VoLTE mechanism :

There needs to be a certain synchronized compatibility to be able to place a VoLTE call. The device along with its firmware and the service provider must all of them support VoLTE and should be able to provide the service in the required area. IP Multimedia Subsystem or the IMS architectural framework is what VoLTE bases its functionality upon. As defined by the Global System for Mobile Communications Association or GSMA in PRD IR.92  to facilitate VoLTE on the LTE wireless broadband service there are specific profiles for control and a router architecture of voice services. After the procedures of authentication and authorization are completed, the MME and the HSS have goes over mobility management communication to ensure the storage of the subscriber profile. The Diameter S6a interface is typically used for the purpose of signaling for these procedures. The device which has already been authorized is capable of establishing the always-on LTE default user data bearer, to do this the authorized device has to communicate with the PGW. The PGW and the device then establishes a user data session. It is important to note that for that particular user data session, which in this case is still under the domain of the default bearer, the PGW is required to establish communication with the PCRF with the help of the Diameter Gx interface to get hold of the the policy and charging regulations that is to be levied on the customer’s that particular data session. Once the PGW and in some cases other PCEFs (Policy and Charging Enforcement Function) have finished up with their procedures, users then can avail Internet services with the help of the established default bearer or can choose to establish a VoLTE call.


Advantages of VoLTE


  1. Efficient uses of network resources – It goes without saying that organizations are constantly looking for solutions that will help them use their resources efficiently. VoLTE is often used to develop a network that is not only simple whose operation expenditures also become immensely more cost effective. This can happen by making the scope for service providers to eventually handle the management of a singular network only. It is in best interest of VoLTE to get rid of other archaic delivery technologies.


  1. Spectrum space – 2G and 3G services have lost much of their significance with the advent of VoLTE. The majority of the spectrum that is used for 2G has the potential to be used for the purpose of significantly increasing capacity for 4G networks. Carriers will be able to free up spectrum space that is used for the archaic voice services with the help of VoLTE.


  1. Superior coverage and connectivity – VoLTE comes with the promise of providing superior indoor coverage than the 2G or 3G spectrums. Experts are of the opinion that calls over VoLTE are able to establish connection twice as fast as other methods that were in use or are currently in use. There is conclusive evidence that the frequencies used by 4G have a far greater capability of an extended reach than some 2G or 3G spectrums.


  1. Business and Enterprise communication services – With the help of VoLTE, it will be possible for us to use native dialer which comes with high-quality voice calls with the help of VoLTE. This in combination with business and enterprise collaboration ensure that enterprise users largely benefit from VoLTE.


  1. No requirement for legacy infrastructure – VoLTE is capable of delivering voice and data services over the same network which means there is absolutely no need to maintain legacy infrastructure.


  1. Improvement in other functions – VoLTE not only increases the functionality of VoIP protocols but are also useful in improving capacity with the help of RoHC / SPS protocols. VoLTE also helps in UL coverage using TTI bundling.



VoLTE is the new buzzword that is taking the world by storm. VoLTE’s main selling point remains an enhanced customer experience, banking on that VoLTE is constantly looking for ways to improve communication that can aid in providing solutions for personal, corporate and commercial users.