In both the core and access portions of the communications network, virtualization is becoming a fundamental building block for use of all network assets, owned and borrowed. Such sharing has been informal for some time, as exemplified by smartphone Wi-Fi access. But sharing mechanisms are becoming more formalized and integrated, as exemplified by
In many cases, Wi-Fi calling is a way to overcome mobile network signal issues indoors, with sessions maintained even when a connection switches from mobile to Wi-Fi, for example.
There are, in fact, a growing number of ways to virtualize spectrum and access assets, both formal and informal. Several methods for bonding licensed and unlicensed spectrum assets are available, including LTE-U, license assisted access and license shared access.
In a growing number of instances, both direct and indirect revenue models might be involved, with a growing amount of integration of owned and third party access assets.
Of course, in other cases, Wi-Fi is a feature of a service the buyer actually does pay for directly. The best example is consumer fixed network internet access, where Wi-Fi typically is the physical mechanism used to connect devices. In that sense, Wi-Fi replaces physical cables and outlets.
Wi-Fi calling also represents an early and informal method of spectrum sharing, in this case treating licensed mobile operator assets and owned or third-party Wi-Fi assets as interchangeable parts of the physical network access infrastructure.
That virtualization of the details of network access already is a building block for service providers
Such as Republic Wireless and Google's Project Fi, and is different from Wi-Fi-only calling offered by over-the-top apps such as Skype, Google Hangouts, Facebook Messenger and WhatsApp.
In the future, MulteFire, a method for creating Long Term Evolution 4G networks entirely using unlicensed spectrum, might be an important platform.