Frequently asked questions about LTE and Voice over LTE ( VoLTE)

Where are phone numbers stored?

In the 2G and 3G Technologies the database Server for the Phone numbers used to call Home Location Register ( HLR ) and in LTE (4G), The database of the telephone numbers and its profile is maintained in HSS ( Home Subscriber Server).

Is this possible to upgrade/convert from LTE to VoLTE?

I have seen many questions regarding LTE and VoLTE. Users asked if they can upgrade from LTE to VoLTE. The both technologies are not in competition but the VoLTE is a solution for voice over LTE network. Long Term Evolution (LTE) standard is for high-speed data access while VoLTE for the voice calls over LTE network.

The VoLTE was delayed in most of the cases because the LTE operators who had existing GSM/CDMA (also referred as 2G), UMTS( 3G) kept on providing the voice services by switching to their old network, the method is called Circuit Switch Fall Back. So they do need to put the systems for VoLTE and they can roll out later.

Nowadays if you are spending the high money on the new smartphone then check if your new device can support VoLTE to keep flexibility as there are few carriers who have VoLTE only network. Also, the LTE operators with an older infrastructure of 3G and 2G expand the network only with LTE and VoLTE for voice so in few areas the voice calls may suffer.

You can check in the setting options if the device supports VoLTE. when calls are made using VoLTE service then 'HD Voice' is visible on the screen. Also, you can search an app which can validate the VoLTE support info for the device.

Since VoLTE feature is not available on all the devices and it's not possible for everyone to purchase a new phone so LTE only operators provide Over the top application to make voice call even the device does not support VoLTE.

How to check if my Phone device supports VoLTE?

You can check in multiple ways:

1. If you have the device with you then it can be checked in the settings if the setting option of VoLTE is available. 

2. Product specification, you can find the specifications if the device supports VoLTE/ HD calling

3. There are applications which will validate if the feature including VoLTE available on your device.

 How does a mobile phone service provider remotely make a phone function only with its own SIM, which previously was functional with other SIM cards also?

The complete name of SIM is subscriber identity module. The id which makes the SIM card unique is the International Mobile Subscriber Identity (IMSI). There is other info on the SIM card like Authentication key which is used to secure the transaction between a subscriber and the network. Other network related information is also stored on the SIM card. Once the SIM start talking to the network then it is primarily identified by the IMSI and then Authentication key to secure the transactions/communications. The detailed information for the subscriber is stored in the carrier’s servers which are changing as per the technology like, GSM, CDMA, PDC, UMTS(W-CDMA) or LTE.

The main job to authenticate the subscriber, billing and call n data related services are carried by the network and its elements which are in form of distributed server.