Twenty years ago, Clayton M. Christensen introduced the term disruptive technologies and now we’re seeing this disruption happening in almost every sphere of life. Uber, Airbnb, Purple, Tesla are disrupting the old traditional models of their respective industries. We’ve seen lot of such innovation in telecom as well with apps like WhatsApp and WeChat replacing SMS in a matter of a few years.
Mobile operators have been battling with churn more than ever due to changing market dynamics with the mobile market reaching saturation. Operators are trying to differentiate themselves from one another by offering different services, technological innovations, better network quality and pricing models. Disruption in telecom is a norm rather than exception with the innovations of today becoming legacy technologies of tomorrow.
Voice over Wi-Fi (VoWiFi) can be one such innovation which is set to change the way we conduct voice calls. In fact, Deloitte predicted that by the end of 2016, about 100 carriers worldwide will be offering at least one packet-based voice service (VoWiFi or VoLTE). In one of my previous articles I explained the benefits of Voice over LTE (VoLTE), but this is where the opportunity lies for VoWiFi.
Most of the time we suffer from poor cellular network coverage inside our homes/rooms due to a number of reasons: location of the home, obstruction due to walls/trees etc. This means that many consumers have problems making calls from inside the home. As per Ericsson’s consumer lab report, at least twice as many smartphone users make voice calls indoors than outdoors, but providing good internal coverage can be technically complex and expensive, particularly for basements and internal rooms.
LTE signals are prone to the same RF limitations as previous generations (2G/3G); signal strength is reduced by walls, obstruction, trees etc. As a result, VoLTE is already facing issues with indoor coverage. Of course, operators have two options: deploy femtocells, or install signal boosters near residences but that means heavy spending on network equipment which most operators will avoid or to offer VoWiFi. Since most of the urban homes are expected to have Wi-Fi and newer smartphones include support for VoWiFi, offering VoWiFi solution as a complementary solution for VoLTE is an automatic choice for operators.
As we know voice solutions are having several benefits over non voice solutions. WLAN has been developed to provide data connectivity between various devices wirelessly. This eliminates cumbersome wiring used before in LAN. Companies and manufacturers are working towards providing voice transmission over WiFi network. WLAN network is also referred as WiFi network.
This voice transmission over WLAN network is referred as VoWiFi. WLAN network is made up of Access Points and Stations. Access Point is like router which is interfaced with internet service provider. Stations are dongles or Wi-Fi card used by the users to access the Wi-Fi network. Now-a-days all the smart phones are coming up with WLAN capabilities and hence it has become essential for companies to have support of VoWiFi to save cost and have efficient interaction between their employees. This helps tremendously in the business management.
Both end users and those in the mobile industry will benefit from Voice over Wi-Fi.
- Can make calls without the need for a mobile signal (e.g. in a remote location or in a property with thick walls);
- Benefit from security being based on SIM-based authentication as for VoLTE; and
- Experience better indoor coverage.
- Unlock revenue opportunities;
- Leverage existing SIM-based security and authentication as for VoLTE;
- Gain the opportunity to access IMS-based services via Wi-Fi access;
- Issue a single bill for the user for all IMS-based services across different access types;
- Ensure ongoing relevance with customers;
- Gain competitive advantage; and
- Benefit from voice/video telephony services provided by IMS and the MMTEL application server as for VoLTE/ViLTE.
- As VoWiFi is still a relatively new service, only a handful of smartphone models support VoWiFi. No backward support for old smartphone models.
- Since operator don’t have control over the quality of Wi-Fi signal at home or malls etc. QoS may be impacted at times. Operators can reserve bandwidth for VoWiFi calling on their hotspots but same can’t be guaranteed on public hotspots/routers.
- As Wi-Fi operates in unlicensed bands, so other radio device may cause some interference although there are many Wi-Fi RRM solutions in the market for handling such issues for operator controlled Wi-Fi Access points.
Why VoWiFi could eventually be the winner?
Due to ever increasing broadband speeds and easy accessibility to Wi-Fi routers, Wi-Fi has become a de-facto standard for internet connectivity in cities and towns which have dense populations and high rises. In fact, the availability of Wi-Fi continues to grow in urban smartphone users households, from 30 percent in 2011 to 61 percent in 2014. There is not an iota of doubt in my mind that Wi-Fi will continue to grow at an overwhelming pace. Ipass predicts there will be one public hotspot for every 20 people on earth by 2018. Operators are likely to leverage on this availability of Wi-Fi to use VoWiFi to extend coverage, particularly indoors and in areas of poor cellular coverage and to reduce churn.
Now think about how although there are a multitude of reasons why and when to introduce VoWifi, all operators will ultimately offer VoWiFi calling services in addition to their current solution offerings, such as CS or VoLTE. Some front-runners eminent telecom company like European T-Mobile and EE are offering the service as a way to attract more subscribers. Others, such as Sprint, are offering it as an alternative solution during the transition to VoLTE. Similar announcements have been made by Verizon and AT&T (US), Vodafone UK, and Rogers Canada. All benefits, however, come with a pricetag. Let’s take a look at a few of expected challenges of VoWiFi, how they may affect subscriber satisfaction, how they can be managed.
Today’s VoWiFi is possible due to 3GPP Release 12 mobility solution with IP address preservation between cellular and WiFi accesses, enabling real-time service delivery and consequently offering operators the opportunity of extending their voice service coverage when migrating from cellular to WiFi. Important challenges can be addressed by utilizing drive testing solutions on the device side, as well as passive and active monitoring at various interfaces and network elements (e.g. S2a interface with Trusted WLAN Access Gate or S2b with enhanced Packet Data Gateway for entrusted WiFi solutions) of WiFi and cellular networks, and by identifying VoWiFi QoE problems that can be related to VoWiFi service accessibility, continuity, retainability and voice quality (MOS).
The overall VoWiFi service quality is first and foremost determined by an optimal cellular – WiFi integration secured by an intelligent network selection performed by the Access Network Discovery and Selection Function (ANDSF) entity. Due to its real time and high quality demands, the voice service case is much more sensitive to improper network selection, such as networks without comparative evaluation of the existing cellular or strong WiFi network, networks that are heavily loaded, networks with lower backend capabilities, or networks expressing ping-pong behaviour), all which can result in the degradation of the user’s perceived voice QoE. Passive and active monitoring allows the detection and troubleshooting of improper network selections as well as their overall impact of perceived QoE if voice quality (MOS like) evaluation is enabled. VoWiFi service monitoring solutions help optimize the performance of various signalling procedures required by the IP address preservation-based service continuity towards high voice QoE. Monitoring solutions running MOS-like evaluations can also estimate the perceived impact of possible longer voice interruptions than the acceptable limits, as caused by signalling procedures affecting the duration of the handover to/from cellular/WiFi.
As the most sensitive service to real-time QoS/QoE continuity, VoWiFI requires that QoS admission parameters of trusted WiFi access to be mapped to cellular parameters for voice-dedicated traffic and default signalling barriers during the migration scenarios from/to WiFi/cellular or calls initiated on WiFi access. Inaccurate mapping at TWAG (or ePDG) and/or device-causing budget delays, packet error losses higher than the maximum acceptable thresholds, as well as annoyingly perceived variable delays generated by extensive additional signalling between TWAG (or ePDG) and devices can be accounted for using passive and active monitoring and troubleshooting. VoWiFi service quality is also determined by the performance of the UE’s VoWiFi clients, and therefore it is highly UE dependent. Poor performing error concealment algorithms implemented in VoWiFi client that are generated too frequently or for too long, with periods of voice stretching or compression, can result in annoying perceived voice quality. In addition, poor performing ANDSF UE-based algorithms using UE measurements of WLAN connectivity, as well as of cellular network conditions, can negatively impact the decision-making process of when to connect to the WiFi access network, therefore impacting the voice service continuity while migrating to/from WiFi/cellular. Another factor impacting the handover decision is the device’s battery. In particular, scenarios with connectivity to entrusted WiFi access (when two levels of encryption are used) are prone to poorer measurements’ accuracy and consequently poor handover decisions. Monitoring and reporting information on the device’s battery status can be used in troubleshooting handover behaviour.
Anyway, customers are willing to pay for a service that’s expected to perform better than the existing services. Packet based voice services have the potential to disrupt traditional CS based voice services. Operators should launch services like VoWiFi when the service is stable in the network, delivering a good quality of service. It has happened in the past, that with new services if a customer faces issues he may not use the service again in near future. This can also result in churn for operators. For MVNOs as well, VoWiFi is good opportunity to enter a new market. VoWiFi shouldn’t be considered as a competitor to VoLTE, rather it complements VoLTE. Time will tell if VoWiFi will change the way we call each other but if early results are to be followed, then it’s on the way to do it!