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23 September 2019

With WiFi 6 and CBRS coming to market together, convergence is in the air

The official start of CBRS services is a genuine milestone in the wireless industry because of the potential to enable many new services providers and industries to use cellular technology. But of course, these organizations have always had a wireless technology, in unlicensed spectrum, at their disposal in the form of WiFi, which has supported a huge variety of enterprise and neutral host models as its capabilities have increased. At the same time the CBRS Alliance was talking about the progress of its OnGo certification scheme, its older equivalent in the 802.11 standards world, the WiFi Alliance, was celebrating the start of certification for the latest generation of standards, 802.11ax, branded WiFi 6.

When considering enterprise, industrial and neutral host networks, WiFi 6 promises many of the capabilities touted for 5G, such as lower latency and higher data rates. But seeing these technologies as competitors is an old-fashioned view in a world where both can live in shared spectrum and so the divisions are blurring.

WiFi is likely to continue to dominate the home and carpeted office markets, but in industrial, critical, highly mobile and wide area environments, it still has disadvantages compared to cellular. In most scenarios, enterprises would ideally have access to both radio networks, preferably managed from a common core so that there is seamless interaction between the two. This is why, while individual stakeholders may still talk in terms of technology battles, two stalwart operator-driven alliances – the Wireless Broadband Alliance from the WiFi side, and the NGMN Alliance from cellular – are cooperating to drive convergence of the two platforms, in order to enable or enhance a wide range of applications.

The two groups published their first joint white paper in January and have followed up with second one, focused on RAN Convergence.  It outlines the benefits of better interworking between 5G and WiFi for MNOs, including improved visibility into WiFi networks, leading to better customer experiences and enterprise services.

The paper also seeks to identify new commercial opportunities created from convergence at multiple network layers, with a particular focus on use cases in manufacturing, smart cities, public hotspots, general enterprise and homes.

“Mobile and WiFi operators, equipment manufacturers and end users all stand to benefit a great deal from the continued convergence of WiFi and cellular networks, especially with the release of WiFi 6 and the continued development of 5G networks,” said Tiago Rodrigues, general manager of the WBA. “As the paper highlights, convergence of 5G and WiFi 6 in the RAN is vital for 5G coverage in dense locations and indoor deployments, giving stakeholders the ability to cost effectively improve performance, while ultimately improving return on investment for mobile operators.”

The paper was supported by 38 leading MNOs with BT, Orange, Rogers of Canada and US Cellular among the active contributors, along with vendors such as Intel, Broadcom, Cisco, Accuris Networks and Huawei.

The WBA was set up to represent WiFi service providers, and has extended its remit in recent years to other unlicensed spectrum technologies. It has been bold in its claims for a central role for WiFi in the broader 5G platform; and in arguing that WiFi will deliver many of the advances that are being discussed around 5G NR. Its official line is that “WiFi will be a core component of 5G communication technologies and WiFi will have a significant impact on the definition of 5G, which will seamlessly integrate with future IMT-2020(5G) standards.”

However, as a solo voice, the arguments have always sounded somewhat defensive, especially when the WBA has been set against its mighty equivalent in the cellular world, the GSMA. By forming a united front with the NGMN – a major powerhouse in the 3GPP arena, and heavily driven by large MNOs – the WBA has greatly amplified its voice and boosted its credibility.

The new report builds on the findings of the original one, which focused on use cases where the optimal solution woud be an integrated 5G/WiFi approach, as well as highlighting the challenges to achieve that. If there is to be any hope of real future convergence, the key hurdles to leap are, the report argues:

  • tighter integration of WiFi access within 5G networks
  • network manageability and policy control,
  • the enablement of WiFi-only devices in a converged environment.

The NGMN Alliance’s CEO, Peter Meissner, raised one of the key issues which has always kept MNOs at a wary distance from WiFi. They may have welcomed some measure of interworking, so they could offload excessive or low value traffic from their precious 4G RANs, but they knew that, once a user moved to WiFi, they could no longer be monetized or their behavior tracked and analyzed. Meissner said that, especially in the enterprise and public WiFi areas, “there is a demand from cellular operators for a standardized solution for improved visibility and control in the configuration and management of WiFi access networks”.

This will be the price for WiFi to be embraced fully within the 3GPP environment, rather than treated as a hard-working but mistrusted poor relation.

MNOs will need WiFi offload less in the 5G era than in 4G, at least once they get to boost capacity in mmWave bands. And they can leverage unlicensed spectrum using the 5 GHz implementations of LTE, the 3.5 GHz MulteFire technology, and in future 5G-Unlicensed (though not until Release 16 is finalized). So it is important, from the WBA’s point of view, to cancel out some of the MNOs’ motives to shift away from WiFi by improving their ability to keep visibility of users and traffic, and monetize them, regardless of their connection.

The January study identified four challenges which must be met to enable fully converged operation, with the associated cost, performance and revenue benefits. These are:

  • enabling WiFi-only devices to connect to the 5G core
  • tight integration between 5G and WiFi networks
  • an interface to enable a certain level of network manageability and policy control between 5G core and WiFi networks
  • the ability for a client to route traffic over one or more access types in an intelligent way, making optimal use of the available connectivity.

Progress on these points is at the heart of the new paper’s findings and recommendations, and the two Alliances’ joint working group will continue to conduct further study on them.