Originally published in Advanced Wireless Technology in December 2017 

As the wireless industry begins to standardize and trial 5G networks, it is useful to consider how voice services, and the networks that support them, might change as well. Currently, most of the industry is still actively converting their subscribers to 4G voice or voice-over-LTE (VoLTE). While VoLTE is still in the early stages in many regions, and has significant adoption in certain markets like North America, Korea, and Japan, the transition to VoLTE will lay the groundwork for operators to begin offering voice and messaging services as an integral part of enterprise, web, and customer support applications. 5G core network architectures will leave the VoLTE application infrastructure largely intact, but will introduce leaner and more scalable core network functions that will rely on HTTP2 for its signaling. In 3G and 4G (VoLTE) networks, signaling was accomplished via SS7 and Diameter, respectively. The voice and messaging infrastructure will need to interoperate with HTTP2 either through new functionality or via a separate interworking network element that will convert the HTTP2 signaling to a legacy signaling protocol.

While voice is often considered an afterthought to developing wireless standards, and despite limited revenue growth potential, consumer voice remains a foundational service for mobile operators. If mobile operators cannot execute a phone call with high quality and reliability, then a consumer will quickly lose confidence in that service, greatly increasing the likelihood of churn. Phone calls are becoming more important with lesser important communications being handled via messaging. Voice quality and reliability will always be important.

VoLTE, and the IMS networks that underpin the service, are necessary for operators to get legacy Time Division Multiplexing (TDM) services and equipment out of their networks. Despite often being fully depreciated, legacy TDM equipment is very expensive to operate and maintain. In many cases development work on these systems has been minimized for the past several years as equipment vendors have invested in all-IP systems and software. Further, as the equipment ages, so does the workforce with the technical expertise to keep the equipment operational. As these older workers leave the workforce, it becomes more difficult and expensive to maintain and operate legacy networks.

The following are several trends related to voice services that mobile operators will likely invest in as VoLTE gets more entrenched worldwide and operators look at migrating to a 5G core network:

Voice Calls Initiated Through Assistant Apps

Consumer voice is changing as well. Voice calls can be initiated through home speaker systems, like Amazon’s Alexa, Google Home, Apple’s HomePod. And voice calls and messaging will be increasingly initiated through intelligent assistant apps (like Apple’s Siri, Samsung’s Bixby, Google’s Assistant, and Amazon’s Alexa) on mobile devices. In this case, voice is treated as an over-the-top service without the quality of service and reliability associated with voice services through the native dialer. Voice and natural language processing, that is converting what people say into a language computers understand and are able to take action against via machine learning models and/or decision trees, is becoming more important to how consumers interact with customer support systems. Chatbots can accomplish the same, reducing the expensive human-to-human interactions by replicating the experience via messaging.

Communications Platform as a Service (CPaaS)

Increasingly consumers can initiate customer support calls or chat session directly through their app. These services are often provided by a CPaaS vendor, who sells wholesale voice and messaging services through open application programming interfaces (API) to their application network. As mobile operators have been deploying similar application infrastructure through their IMS and VoLTE initiatives, they are increasingly considering their own open API initiates with the intention to start monetizing network traffic that would otherwise be purely over-the-top. With direct access to operator networks, app developers will likely experience faster time to market, due to less testing, and a better experience for their end users. Today, CPaaS companies like Twilio are offering voice and messaging APIs to web properties like WhatsApp and Uber.

Unified Communications as a Service (UCaaS)

As the market for consumer voice is increasingly limited in terms of direct, ARPU-related revenue growth, operators will likely begin to look at the enterprise and small and medium business markets for growth. Ideally, these operators will have the network and application resources to easily add UCaaS application servers to their IMS networks. It is costly and time consuming to develop a sales channel to market and sell directly (or indirectly) to business customers, so operators have been slow to pursue this opportunity. However, with VoLTE, IMS, and the transition of enterprise voice services to the cloud, this convergence of trends is creating a window of opportunity for mobile operators to become more active in pursuing enterprise and SMB voice services.

While 5G will not immediately introduce a vastly new type of voice or communications service, the changes network operators are making to their core networks will better prepare them to address the lucrative enterprise and small to medium business markets, and to add communications as a feature to assistant apps and customer support features within web properties. As 5G matures we may see wireless speeds and latencies to the extent that virtual reality and augmented reality become more a part of mobile service offerings.