AT&T sketched out its plans to start testing Integrated Access and Backhaul (IAB) technology during 2020, saying it can prove a reliable backhaul alternative to fiber in certain cases, such as expanding millimeter-wave locations to reach more isolated areas. Verizon also confirmed, without adding any details, that it plans to use IAB, which is an architecture for the 5G cellular networks in which the same infrastructure and spectral resources will be used for both access and backhaul.   IAB will be described in 3GPP Release 16 (see 3GPP section below for more details).

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“Fiber is still required in close proximity to serve the capacity coming from the nodes, so if it can be extended to each of the nodes, it will be the first choice,” said Gordon Mansfield, VP of Converged Access and Device Technology at AT&T. in an statement emailed to FierceWireless.

“From there, IAB can be used to extend to hard to reach and temporary locations that are in close proximity. As far as timing, we will do some testing in 2020 but 2021 is when we expect it to be used more widely,” he said.

Verizon also told Fierce that it has plans to incorporate IAB as a tool. It doesn’t have any details to share at this time, but “it’s certainly on the roadmap,” an unknown Verizon representative said.

Earlier this year, Mike Dano of Lightreading reported:

Verizon’s Glenn Wellbrock said he expects to add “Integrated Access Backhaul” technology to the operator’s network-deployment toolkit next year, which would allow Verizon to deploy 5G more easily and cheaply into locations where it can’t get fiber.

“It’s a really powerful tool,” Glenn Wellbrock, director of architecture, design and planning for Verizon’s optical transport network, explained during a keynote presentation here Thursday at Light Reading’s 5G Transport & the Edge event.

Wellbrock said IAB will be part of the 3GPP’s “Release 16” set of 5G specifications, which is expected to be completed by July 2020. However, Wellbrock said it will likely take equipment vendors some time to implement the technology in actual, physical products. That means 2020 would be the earliest that Verizon could begin deploying the technology, he added.

Wellbrock said IAB would allow Verizon to install 5G antennas into locations where routing a fiber cable could be difficult or expensive, such as across a set of train tracks.

However, Wellbrock said that IAB will be but one tool in Verizon’s network-deployment toolbox, and that Verizon will continue to use fiber for the bulk of its backhaul needs. Indeed, he pointed out that Verizon is now deploying roughly 1,400 miles of new fiber lines per month in dozens of cities around the country.

He said Verizon could ultimately use IAB in up to 10-20% of its 5G sites, once the technology is widely available. He said that would represent an increase from Verizon’s current use of wireless backhaul technologies running in the E-band; he said less than 10% of the operator’s sites currently use wireless backhaul. He said IAB is better than current wireless backhaul technologies like those that use the E-band because it won’t require a separate antenna for the backhaul link. As indicated by the “integrated” portion of the “integrated access backhaul” moniker, IAB supports wireless connections both for regular 5G users and for backhaul links using the same antenna.

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According to 5G Americas, the larger bandwidths associated with 5G New Radio (NR), such as those found in mmWave spectrum, as well as the native support of massive MIMO and multi-beams, are expected to facilitate and/or optimize the design and performance of IAB.

5G Americas maintains that the primary goals of IAB are to:

• Improve capacity by supporting networks with a higher density of access points in areas with only sparse fiber availability.
• Improve coverage by extending the range of the wireless network, and by providing coverage for isolated coverage gaps. For example, if the user equipment (UE) is behind a building, an access point can provide coverage to that UE with the access point being connected wirelessly to the donor cell.
• Provide indoor coverage, such as with an IAB access point on top of a building that serves users within the building.

5G Americas also said that in practice, IAB is more relevant for mmWave because lower frequency spectrum may be seen as too valuable (and also too slow) to use for backhaul. The backhaul link, where both endpoints of the link are stationary, is especially suitable for the massive beam-forming possible at the higher frequencies.

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3GPP Release 16 status of work items related to IAB:

(Note: Study is 100% complete, but others are 0% or 50% complete):

References:

https://www.fiercewireless.com/wireless/at-t-expects-to-test-iab-2020-use-it-more-widely-2021

https://www.lightreading.com/mobile/5g/verizon-to-use-integrated-access-backhaul-for-fiber-less-5g/d/d-id/754752