How Interoperability Works in 5G networks

5G networks represent the next generation cellular networks posed to replace 4G networks. The network represents a shift from consumer technologies to industrial technologies and promises to usher in an era of exponential connectivity, low latency, ultra high reliability, seamless connection of high dense machines or sensors spread over geographic locations.

In order to meet the exponential demand, it is anticipated that 5G networks would rely on a combination of technologies from Wi-Fi, LTE (Long Term Evolution), small cells, satellites, relays, various access technologies etc. For this to work, the 5G core has been virtualized and softwarised to allow these technologies work interoperably and seamlessly.

Here, I will look at one of the techniques introduced by the 3gpp (third generation partnership project) , in one of their releases, aimed at facilitating interoperability of these technologies.

In the 4G network, when a user attempts to make a voice call or connect to the internet, both voice or data connections typically pass through the cellular network. Alternatively, the user could attempt to make the same voice call or connect to the internet using Wi-Fi, from a hot spot, for example, and thereby avoid incurring charges from the mobile operator. Both cases are depicted below in figure 1.

However, in a 5G network, the network could carefully combine the resources of the both cellular network (2G, 3G, 4G, 5G etc.) and Wi-Fi to offer a superior service to the user. As shown below, the voice and data traffic are split and passed over all networks, see figure 2.

The 5G network can perform any of the functions listed below

1. Steer and select the best network: the 5G network is able to steer the traffic over either the cellular network or Wi-Fi, based on the best network for the user.
2. Switch traffic: when a user is already using the resources of the cellular network, the 5G network is able to hand over the traffic to a wiFi network and vice-versa.
3. Split traffic: the 5G network is also able to split the user’s traffic over all available networks e.g. it could direct voice traffic over a gsm network whereas it directs the data traffic over a Wi-Fi network.

These functions would be performed based on certain rules embedded within the network. The steering, Switching and splitting traffic over various access networks may sound trivial until one considers some of the anticipated use-cases of 5G. For instance, consider an autonomous car driving and it encounters a child crossing the road and it needs to make a quick decision on how to avoid the child, then one would appreciate the need for the network to be able to quickly switch network resources, when one access network suddenly becomes unavailable. The same applies to a robot performing surgical procedures, in the wake of a surge in the use of tele-medical applications, due to social distancing directives.