Skip to main content
Exploring what’s next in tech – Insights, information, and ideas for today’s IT and business leaders

Convergence of Wi-Fi and 5G offers greater enterprise flexibility

The designers of 5G and Wi-Fi borrow from each other and make their networks more interoperable.

Technology leaders now have greater flexibility in network planning, thanks to a growing convergence and cooperation among the two primary wireless networking standards: Wi-Fi 6 and 5G.

"Unlike past generations of wireless, Wi-Fi 6 and 5G are designed to work together smoothly, and the wireless industry appears headed toward a future in which devices can roam securely and seamlessly between all types of wireless networks," explain experts in a Deloitte 2022 outlook analysis, putting to rest the myth that 5G would supplant Wi-Fi as the network of the future.

According to Stuart Strickland, a Hewlett Packard Enterprise Fellow, the standards now support deep integration between Wi-Fi and 5G, but real-world implementations have more modest aspirations. Strickland sees the path to this goal running on two tracks: improved user experience and easier administration.

"We want to see services persist as devices move between Wi-Fi and 5G coverage with no user intervention," says Strickland. "We want to see comparable and predictable quality of service and not drop any calls."

He says the network administrator "wants to deploy a private 5G and a private Wi-Fi network with the same basic tools, manage credentials in the same ways, provide role-based access and segregation in the same way they do in their Wi-Fi and fixed networks, and control the whole thing through the same pane of glass."

The history of Wi-Fi and cellular

Smartphones have had Wi-Fi support from the earliest models, but the Wi-Fi and cellular networks were completely separate, and Wi-Fi had no role in voice calling.

Both the devices and the network changes to smooth the relationship between cellular and Wi-Fi happened mostly with 4G LTE and VoLTE (Voice over LTE), standards that have been uniform in the U.S. for five or six years. "The telephony [cellular] system is fully IP-based, so the handoff from a Wi-Fi call to a carrier network works right now," says Florin Baboescu, principal engineer at Broadcom and chair of the 5G group at the Wireless Broadband Alliance (WBA).

Please read: Best of Enterprise.nxt: All about 5G networks

Baboescu adds, "Once VoLTE was in place, the next step was voice over WLAN, which in this context is Wi-Fi." This feature, probably called "Wi-Fi calling" on your phone, allows the phone to establish a voice telephony path over a Wi-Fi network to the carrier. Wi-Fi calling took a large amount of traffic off of carrier networks and allowed customers to make reliable calls, over secure connections, where a cellular signal might not be available.

5G optimizes for Wi-Fi

The designers of 5G saw that everyone was using Wi-Fi and made it so that Wi-Fi could work as well as possible with a 5G network. It's almost as if the Wi-Fi is part of the 5G network.

As Baboescu puts it, "At Broadcom, one of our goals for 5G system design was always to be able to have Wi-Fi as a viable access alternative to cellular." In a 5G system from the very beginning, Wi-Fi access is seamlessly integrated compared with 4G, so there is a lower cost for implementation. "If you want to deploy your own 5G services, you can definitely use Wi-Fi as a viable connection option," he says. Operators could even develop 5G services using unlicensed spectrum while using Wi-Fi as the radio access network, the local network through which the handset connects.

In 4G, you couldn't access operator services without having access via licensed spectrum through the operator core network. On 5G, you can connect over Wi-Fi, and if your handset has the proper credentials, you can have full access to carrier services. Strickland notes, "For those devices that use their 5G SIM credentials to access Wi-Fi via Passpoint, the air interface is just as secure as 5G radio networks."

Other improvements make the systems more efficient. While in 4G there are multiple ways through which a terminal device can connect over Wi-Fi access, with impacts on both device and network complexity, in 5G there is a unified way to use IP-level connectivity over Wi-Fi access. The 5G design for Wi-Fi access extends the IPsec tunneling mechanism used for Wi-Fi calling in 4G.

However, the IPsec tunnel used for Wi-Fi calling does not come cheap. It puts a processing burden both on the handset and the network core, consuming power. The encryption/decryption burden in the network itself is considerable. One of the changes in 5G to mitigate this problem is to allow the handset to connect using a null (unencrypted) IPsec tunnel if the connection is over a trusted, encrypted Wi-Fi network. In this way, there will not be double encryption when the network connection is encrypted.

6E is sexy

The Wi-Fi people have been doing their part, too. The most significant improvement in support for 5G has been indirect. Wi-Fi 6E, which brings Wi-Fi 6 to the immense 6 GHz band and is shipping today, will take high-bandwidth applications off the 2.4 GHz and 5 GHz bands. These bands are crowded and have comparatively small channels, which are more than adequate for serving voice but are suboptimal for applications like high-def video.

Please read: Wi-Fi 6E and the insatiable demand for network bandwidth

6E adds 1.2 GHz of virgin spectrum to the Wi-Fi pool. The new band allows for large channels while still maintaining network density. Strickland says, "Spectrum constraints in the 5 GHz band had previously required a tradeoff: Sparse home networks could take advantage of broad 180 MHz channels, but dense enterprise environments needed more non-overlapping channels so were typically limited to 40 MHz and sometimes even 20 MHz. Now, with Wi-Fi 6E, they can have both dense networks and wide bandwid

Cellular's move into Wi-Fi turf

Simultaneous with Wi-Fi's leaning on similar technology to cellular, 5G is also taking lessons and space in the shared 5G band from Wi-Fi.

"The task of cellular networks to address enterprise markets has been to make them look like Wi-Fi and fixed networks in terms of giving the venues or administrators of local networks flexibility," says Strickland.

More noticeable, though, is that 5G has begun using the same frequencies as Wi-Fi through what's called 5G NR-U (New Radio Unlicensed), which enables cellular leveraging unlicensed frequencies in 5 GHz and eventually the 6 GHz band, although 3GPP standards for this are not complete. One of the purposes is to provide higher performance and better end-user experience.

The coexistence of Wi-Fi and cellular transmissions has been contentious. A fundamental principle of gaining access to the medium is Listen Before Talk (LBT). 5G NR-U (and its 4G LTE equivalent, License Assisted Access, or LAA) can severely impact Wi-Fi. So a harmonious coexistence between Wi-Fi and 5G NR-U using collision avoidance methods like LBT is required.

Please read: 5G and Wi-Fi 6 and the challenges of edge networking

5G NR-U and Wi-Fi cannot demodulate or understand each other's transmissions. So they must listen for and detect energy from each other's transmissions.

Standards bodies and vendors are working on LBT as we speak. Strickland explains that in late 2021, the European standards body ETSI hashed out plans for standards that level the playing field for the rules around how Wi-Fi and cellular networks share unlicensed spectrum in the 5 GHz and 6 GHz bands.

While ETSI only has jurisdiction over the European Union, Strickland says that the decisions it reaches "generally reverberate throughout the world" on these issues.

What happens as they meet in the middle

According to Deloitte, enterprises tend to favor Wi-Fi for indoor use cases, on-campus environments, and fixed use cases. At the same time, they lean more heavily into 5G for outdoor use cases, off-campus environments, and mobile situations.

One of the components that enterprises and vendors will need to negotiate as they plan mixed network implementations is the issue of quality of service (QoS), a critical component for low-latency and real-time applications. Wi-Fi slices up QoS thresholds into only four access categories, whereas cellular maps dozens of them. These categories allocate the right to transmit on the wireless medium, known as a transmit opportunity.

Wi-Fi's categories prioritize voice and video traffic, but they don't guarantee throughput. The purpose of these categories is to lower the contention window for devices with specific traffic. As mentioned previously, Wi-Fi devices listen before talking, and if they have voice or video traffic to transmit, they would have a shorter contention window.

With the distinction between cellular and Wi-Fi QoS, the industry needs to figure out better methods to share QoS expectations from the operator to over-the-air transmissions to create a fair access method between technologies.

"The current gap is in ways to share those expectations between privately managed Wi-Fi networks and the 5G cellular core, but there's work underway to open protocols to do that," says Strickland, who is also chair of the Access Network Quality of Service work group at the WBA, which is tasked with this work. "All of the information is available now to a local Wi-Fi network to make itself appear as though it were just another node of the cellular network in terms of neighbor cell information. Information about the current network's load and available resources is there. But it's not clear yet that the operators—if they had access to that—know how to digest it."

Strickland says that as a vendor, his ambition is to make much of that prioritization seamless for enterprise customers that want decisions made automatically by the network. At the same time, customers need tools to help them identify customized settings that can enable them to meet specific requirements. Right now, everybody is negotiating a situation where the technologies converged more quickly than the working practices of mobile network operators and local networks, he says, so it's just a matter of the industry coming into equilibrium.

Rowell Dionicio contributed to this article.

This article/content was written by the individual writer identified and does not necessarily reflect the view of Hewlett Packard Enterprise Company.