The mobile virtual network operators are continuously pressing for VoLTE or Voice Over LTE to bring a standardized level for transferring the voice-traffic over the LTE. Initially, the LTE was viewed as a fully IP cellular mechanism only for carrying the data and the operators were allowed to carry the voice either through using VoIP or reverting to 3G/2G systems. However, the operators have realized that the absence of standardization might pose problems, especially in roaming scenarios. Besides, it wasn’t often internalized that SMS is a prime requirement to set-up several mobile broadband networks and its absence is taken as a show-stopper. Since mobile operators get more than 80 percent of revenue through SMS and voice traffic, it’s essential to come up with a standardized and viable scheme to offer these services & protect revenue.
Options for VoLTE
A number of options have been proposed for carrying voice over the LTE
- Circuit Switched Fall Back or CSFB - CSFB has got standardized under 23.272 3GPP specification. The LTE CSFB utilizes varied network elements & processes to allow circuit in falling back to 3G/2G connection before the initiation of circuit-switched call. This specification enables carrying of SMS.
- SV-LTE – Simultaneous Voice LTE permits the run the packet-switched LTE operations simultaneously with circuit-switched voice facility. SV-LTE is a favorite option for many operators- the only con is that it would need 2 radios to run simultaneously that could be damaging for battery life.
- VoLGA - VoLGA (Voice over LTE via GAN) standard has been based on existing 3GPP GAN standard & the goals was to permit LTE consumers to achieve SMS, voice & other different circuit-switched services consistently as they transit between UMTS, GSM & LTE-access networks.
- One Voice or VoLTE- This scheme involves IMS allowing it in securing a place in rich media solution.
All Good, but still no VoLTE
Unlike the earlier standards of cellular telecommunications including GSM, the LTE isn’t equipped with dedicated channels to help in circuit switched telephone network. LTE, instead, is a complete IP system offering end-to-end IP network from mobile device to core network and out again. Thus, VoIP has to be used to provide some voice connection on standard LTE. Any of the voice services has to have the aim to utilize low latency and QoS features present within the LTE to assure an enhancement over standards featured on 3G and 2G networks. However, complete VoIP on LTE comes with serious issues that would take longer to resolve.
Nerdy Talk on VoLTE
One Voice for the Voice over the LTE was devised by a collaborative endeavor between more than 40 operators including Verizon Wireless, AT & T, Alcatel-Lucent and Nokia. The GSMA Mobile World Congress, 2010, witnessed GSMA announcing their support for One Voice system to offer Voice over the LTE.
VoLTE, the IMS-based specification would allow the system in getting integrated with the application suite that would be made available on the LTE.
There are three interfaces that are required for VoLTE service:
- UNI It is to be situated between operator’s network & user’s equipment.
- R-NNI- It is to be situated between Home & Visited Network & works for user in roaming.
- I-NNI- It is to be situated between networks of 2 parties making call.
VoLTE will include the following elements
- It’s essential to assure continuity of the Voice calls while user moves from LTE coverage region to another requiring fallback to other technology and this could be achieved utilizing SR-VCC.
- Optimal routing for the bearers of voice calls is needed if customers are on roaming.
- It’s necessary to establish commercial frame for roaming and interconnect for the services implemented utilizing VoLTE definitions that would enable in setting up roaming agreements. There should be the provision of the capabilities attached with roaming hubbing.
- A complete security and fraud-threat audit is needed to prevent unauthorized entry into the network and hacking.