VoLTE

Voice over Long-Term-Evolution or VoLTE is a type of VoIP (Voice over Internet Protocol) calling that allows voice calls to be made over the 4G/LTE (Long-Term Evolution) mobile networks.[[1]]( Unlike 2G or 3G, 4G/LTE and 5G/NR are data-only standards and have no built-in calling functionality, let alone one as well standardized as the traditional Circuited Switched calling from 2G and 3G (GSM/UMTS). This poses an issue for consumers, since enabling 4G or 5G calling on devices requires explicit carrier software or firmware support, including for Emergency Calling. Two identical phones running different carrier software can have different VoLTE Calling and Emergency Calling functionality on various networks.[[2]]( Voice over LTE, aka '4G Calling', is a software-/firmware-based calling solution for mobile sector. The world has used VoIP Calling for decades, but introducing VoIP data based calling into the mobile sector has proven very difficult. VoLTE devices have been around since as early as 2013. Over many years, however, the industry has failed to ensure interoperability.[[3]]( With 2G or 3G still in service, consumers do not experience any loss in device functionality by switching to a competing provider. However, with the shutdown of 2G/3G services, consumers may no longer make nor receive standard phone calls on their existing 4G devices with their preferred mobile carriers. This also impacts Emergency Calls and Roaming Calls, as not all devices that support VoLTE calling can place Emergency Calls or Roaming Calls over 4G. Due to the compatibility and standardization issues with VoLTE, the ability for consumers to use devices purchased from any provider in the world will no longer exist like it did with 2G and 3G (Circuit Switched) networks. Currently, phone carriers can use this telco specific VoLTE firmware requirement as a stealthy way of network locking their devices, which prevents customers from switching to competitors or from using 'BYO' devices.[[4]]( Some carriers, like AT&T , only activate devices that they sell in their store, preventing the unlocked variants from working.[[5]]( Handset makers and network operators also engage in behavior that restricts the use of devices on different networks and otherwise anti-competitive behavior.[[6]]( VoLTE has been supported with Qualcomm Snapdragon Chipsets since at least 2013/2014 (e.g., Snapdragon 800/801), but not all Android devices that have been sold have VoLTE enabled by the manufacturer.[[7]]( [[8]]( In many instances, devices will also lack the correct carrier network configurations/profiles to support VoLTE calling on all networks.[[9]]( Unlike calling with 2G and 3G, there is no single configuration for VoLTE that all devices and networks universally support. Some networks support the GSMA IR.92 'Open Market Device' Configuration.[[10]]( This configuration is intended as a generic/global VoLTE configuration that can be used by Open Market (non-carrier) devices.[[11]]( 4G/LTE Devices that lack native VoLTE calling support are reliant on 2G/3G Networks to make or receive calls (via Circuit Switched Fallback - CSFB). Without either 2G or 3G Networks, those devices do not have call service. A device may be marketed as having VoLTE support. However, the device may only make calls on some networks due to varying network configurations and VoLTE standardization issues.[[12]]( In some instances, the retail versions of devices have been sold without VoLTE Calling on any networks (depending on brand/market/region). However, the exact same device purchased directly from a carrier (with carrier software) will support VoLTE on that carrier network.[[13]]( [[14]]( Equally, some handsets purchased from another carrier or from another market may not be configured (in software) to support VoLTE on all networks within a given country. This issue primarily affects Android Phones and non-Apple devices. The iPhone 6 (2014) with iOS 10 and other newer devices support VoLTE