How 5G and Wi-Fi 6 will work together
Considering how much we all rely on Wi-Fi and cellular communications to work seamlessly, the two do not have a history of working well together. That's one thing the latest generations—5G and Wi-Fi 6—aim to change.
As the two technologies race to provide wireless access for business use cases, verticals, and IoT devices, a key issue is how to integrate 5G and Wi-Fi so that users can roam between them painlessly. Critical business applications requiring low latency and near-real-time communications over a wireless medium are the next frontier in data communications. 5G and Wi-Fi give us more ways to access the cloud.
Wi-Fi is ubiquitous and seen as a commodity nowadays. We expect Wi-Fi service in shopping centers, at medical offices, and on planes. The Wi-Fi access medium has been around for more than 20 years.
5G is the next iteration of cellular technologies. Consisting of new architecture such as next-generation radio network and 5G core, the building blocks will contain many of the same tenets of mobility used in Wi-Fi, which are access, transport, cloud, network applications, and management.
In 2018, we got a taste of cellular and Wi-Fi working together by having the carriers perform Wi-Fi offload for phone calls: the birth of Wi-Fi Calling. It was a way for carriers to tackle the challenge of not having enough cellular signal. The core concept behind Wi-Fi Calling involves the phone making a connection back to the carrier's network through a potentially untrusted Wi-Fi network through the use of IPsec tunnels.
This allows voice calls that normally connect over cellular to use Wi-Fi. Wi-Fi Calling has become wildly popular with carriers, with support from more than 128 operators in 47 countries, according to a list maintained by Apple. A live-call handoff still is challenging today, and coverage gaps in a Wi-Fi environment lead to dropped calls. But the industry is working toward making seamless handoffs, even between 5G and Wi-Fi, something that we can take for granted.
What about Passpoint?
For those who thought Passpoint solved the issue, well, it does lead us down the right path. Seamless offloading from the cellular network and onto Wi-Fi is the goal of Passpoint. But it doesn't address true roaming between Wi-Fi and 5G.
Passpoint allows a cellular user to connect to a Wi-Fi network without the user's intervention, utilizing the carrier's device credentials. This promises to dramatically simplify the offloading of 5G data and voice traffic onto the local Wi-Fi network.
Passpoint is currently supported by all the major U.S. operators and provides a way for devices receiving services from a 5G network to discover and get onto a Wi-Fi network when 5G coverage drops off or better Wi-Fi coverage becomes available. While Passpoint automates network discovery and streamlines access, it still requires roaming agreements between the identity provider (probably the carrier) and the Wi-Fi provider (airport, library, coffee shop, and so on).
The coexistence between 5G and Wi-Fi is here, but we need convergence. 3GPP, the group behind 5G standards, studied how 5G can be extended to support Access Traffic Steering, Switching, and Splitting (ATSSS) with non-5G networks. We have also seen discussion of methods for the convergence of Wi-Fi and 5G from the Wireless Broadband Alliance.
We will see further coexistence in the 6 GHz band. Discussions of how 5G and Wi-Fi will play nicely together have been less than fruitful, but we need the convergence of the two technologies.
Wi-Fi as a RAN
An architectural change in 5G compared to 4G opens up a new level of integration. In both 4G and 5G, the part of the network that talks directly to client devices and connects them to the core network is called the radio access network (RAN).
In 5G, the design is modular enough that any network that services the RAN interfaces to the core can serve as the RAN. It needn't be cellular at all. It could be a Wi-Fi 6 network. It could also be one of a few Industrial IoT network protocols like LoRa, LPWAN, or Sigfox. This hasn't been implemented anywhere yet, but the design is meant to allow it.
And there are good reasons to do it. A telco might interface its own core to a customer's Wi-Fi 6 network to avoid deploying an actual cellular network, and it still gets control and visibility into the customer network.
How the convergence will happen
The convergence will take time, but the work has begun and will proceed along these paths:
- Discovery and authentication: A mechanism in the management framework for the device to identify authorized Wi-Fi networks and connect to them using the device's 5G credentials.
- Mobility with continuity: A mechanism in both the Wi-Fi and 5G networks to transfer the call between them without the dropped-call problems of Wi-Fi Calling.
- Data routing: A mechanism to route data connections to and from the phone either through the cellular or local Wi-Fi network.
- Aggregation and load balancing: The use of both Wi-Fi and 5G for the most efficient utilization of available network resources.
The mechanisms making these decisions could do so for a variety of reasons under a variety of criteria. The cellular network may be congested, even if it's normally a faster route to the destination. A need for greater bandwidth might justify aggregating cellular and Wi-Fi, but many factors, including battery level, might mitigate against it.
Some presence in the network has to track all of this and balance it against policy. Such a system requires a lot of coordinated intelligence in the networks.
Wi-Fi 6 is another requirement for all of this to work well. Keeping up with 5G's quality of service and determinism expectations is beyond the capabilities of earlier Wi-Fi generations.
You shouldn't have to care
The day will come, in not too many years, when we won't have to pay attention to what network we're on, and the idea that we should have to will seem strange. It's just not reasonable to expect users to manage the shift from Wi-Fi to cellular and back manually. It should just work.
It's time to build better devices, better networks, and better management layers and design better policies so that mobile devices work as well as they can. The roadmap from here to there is clear.
Wi-Fi and 5G convergence: Lessons for leaders
- As much as business is accomplishing on wireless networks today, networks can and will get a lot better
- Wi-Fi and cellular are different, but users shouldn't have to care about the difference. They should just be able to do their work.
- If businesses want to get the most out of their technology, they need to be open to new generations of those technologies.
This article/content was written by the individual writer identified and does not necessarily reflect the view of Hewlett Packard Enterprise Company.