Mobile voice revenues are declining and CSPs (communication service providers) are finding ways to reduce the impact. Data revenues are increasing, but they are unable to compensate for a loss in voice revenues by identical measure. As competition intensifies, CSPs must tailor their offerings so as to offset competitive pressures.

VoWiFi (voice over WiFi) emerges as an enabler of communication medium by a combination of hardware and software over WiFi. Voice calls are sent in the form of data in packets via WiFi network instead of a cellular network. It uses WiFi connection present at a premise or public/private WiFi hotspot (e.g. commercial/private campus, airport, cafe, library, train station, etc.). WiFi can be utilized at places where cellular network is often unavailable/patchy (e.g. basement or houses in remote areas). The basic difference between VoWiFi, VoLTE and traditional calling is that traditional calling uses circuit switched networks for calling which requires maintaining 2g/3g technologies. LTE is a data network which uses an additional network to provide voice calling known as an IP Multimedia Subsystem (IMS) network. Voice signals are given higher priority within this network arrangement. VoWiFi also uses the same access network, but a separate packet switching (PS) network to ensure quality of service.

VoLTE suffers from the same frequency oscillation as previous generation networks (2g/3g) leading to reduced signal strength. Signals are obstructed by walls, trees etc. which leads to loss of connectivity or poor voice quality. VoWiFi may prove to be a feasible option in this scenario as most subscribers are within WiFi range when they are indoors. CSPs can offload to these WiFi networks and provide good quality service.

CSPs got interested in VoWiFi post launch of Apple's iOS8 and iPhone 6. T-Mobile became first major operator to launch VoWiFi with Apple iPhone 6. MVNO's like Republic Wireless are offering VoWiFi since 2011.

VoWiFi differs from OTT (over the top) services - Skype, etc. VoWiFi doesn't require a third-party app for calling; instead, utilizes device native dialer and number provided by the network operator. VoWiFi is available on phones (Android and iOS) where the CSP has created a VoWiFi infrastructure. Without this investment, VoWiFi services are not accessible to the consumer. Android OS allows the automatic switch to WiFi calling whereas iOS requires permission.

We believe, simply laying down the WiFi infrastructure will not suffice the operators' need in terms of earning revenue and alleviating CAPEX and OPEX cost. Operators require a platform with enhanced features enabling them to monetize from their WiFi offerings and let them deliver differential and innovative services to hasten value and rapidly change their monetizing landscape.

VoWiFi is a communication network based on three components:
1. WiFi network
2. CSPs network infrastructure
3. User's device.

Acceptance of WiFi calling is growing around the world and CSPs are deploying solutions to address needs of subscribers. WiFi calling transforms a WiFi hub into a mobile tower and acts as an extension to CSPs network. These so-called mobile towers extend CSPs network without incurring additional costs of deployment and operation.

Evolving VoWiFi Business Models
• WiFi calling bundled with residential and enterprise plans
• WiFi calling with roaming packages, service bundled with Cable MSO subscription, etc.
• Fermium public WiFi supported by advertising, data analytics and location-based services, to recover WiFi network costs

Voice over WiFi will not guarantee coverage, but when integrated with LTE it has potential to offer improved services. The combination of hardware and software between 3G-WiFi, 4G-WiFi and LTE-WiFi ensure voice travel on different networks efficiently. WiFi calling creates many opportunities for CSPs, not feasible earlier.

Due to its obvious advantages VoWiFi has been adopted by many CSPs across the world.

Sterlite's VoWiFi solution
Sterlite's provides end-to-end integration service to its customers and provides a comprehensive WiFi calling solution. Its major characteristics are:
• HD voice quality & text services with better indoor coverage
• Seamless interworking & voice mobility support between legacy (3G/4G) and WiFi networks
• Secured EAP SIM/AKA authentication over 3GPP enabled SWm via 3GPP AAA
• Device agnostic support - EAP SIM/AKA
• Customized policy decisions and supports different charging models
• Next generation WiFi calling with VoWiFi + VoLTE
• End-to-end connection between device & ePDG via secured IP sec tunnel
• Cost effective with less roaming charges
• Supports law intercept and emergency calling feature

An effective handover and a qualified technology partner like Sterlite can help CSPs meet these network challenges.
Akshat Joshi
VP - WiFi Business