5G network performance is expected to deliver a huge leap in capacity and bandwidth. But for 5G users to fully benefit from the faster network speeds and low latency of 5G, operators must ensure that their backhaul network is also performing at its peak.
Backhaul, which is the term used for carrying network traffic from the cell site to the mobile core, hasn’t had any major technological advances in a number of years. Most operators have been using a mix of technologies to backhaul their traffic, including point-to-point fiber, cable and, to a lesser extent, microwave. And those technologies will likely continue to play a key role in 5G backhaul. But now there’s a new tool that promises to make a big impact on 5G backhaul.
Integrated Access Backhaul (IAB) is part of 3GPP Release 16. What makes it so appealing is that operators can use their existing 5G air interface for backhaul as well as access. That means that instead of having to deploy a dedicated fiber link to a cell site for backhaul, operators can instead dynamically allocate a portion of the bandwidth they are using to deliver 5G services and instead use it for backhaul. This is a big advantage because operators will no longer have to wait for a fiber link before a 5G cell site can be up-and-running.
“To speed up deployment, we can take advantage of wireless backhaul over mmWave,” said Bill Stone, vice president of planning for Verizon, which has been testing IAB. “This will allow us to bring up a node in hours instead of waiting for fiber.”
Not a fiber substitute
Verizon recently completed a proof-of-concept IAB trial with Ericsson using its 5G Ultra Wideband service over millimeter wave (mmWave) spectrum. The trial was conducted with 5G radios that had IAB functionality. However, the radios that Verizon has already deployed in its 5G Ultra Wideband network do not have IAB. Stone said that Verizon will commercially deploy the technology in the next year or two. “This capability will be fully integrated into the radios in part of our 5G expansion,” he said.
But Stone was quick to add that IAB will not be a replacement for fiber. “Fiber is still one of the key components of a 5G network,” he said. “Fiber remains a high priority.”
Where IAB will come in handy is in areas where fiber is difficult, or impossible, to deploy. It can also be used for an event or an emergency situation like a natural disaster where 5G coverage is needed quickly or temporarily. “It’s not something that we need everywhere so we can be selective about which radios get this capability,” Stone added.
Stone said that outfitting 5G radios with IAB doesn’t require “manual intervention” and added that it is a software upgrade that can be configured remotely. But he noted that Verizon is still working with its vendors on the details of deploying the technology. “We are working through the process to make it simple and make it happen quickly."
IAB is much more than just a stop-gap measure, however. According to Chris Pearson, president of 5G Americas, IAB will be particularly helpful in areas such as dense urban corridors where it’s difficult to get fiber deployed because it often requires companies to tear up streets and impede traffic. “This gives operators some real choices in dense urban areas,” Pearson said. “When it comes to the economics, efficiency and performance of backhaul, there hasn’t been a lot of choices until now.”
5G Americas earlier this month released a white paper detailing new innovations in 5G backhaul and Pearson said that while lots of fiber for backhaul has already been deployed in the U.S., it’s still not enough to fulfill all the backhaul requirements of 5G. “Densification is needed to fulfill the promise of 5G and you will need to have cell sites all over the place and those cell sites will need backhaul,” he said. “IAB is really a great choice. It’s a breakthrough.”
Spectrum constraints
Not only does IAB give operators the option of using the same antenna for both access and backhaul but they can also use the same power supply. On the downside, operators will have to use some of their spectrum assets for IAB.
Pearson said that in mmWave spectrum, that shouldn’t be an issue because mmWave spectrum can deliver such a large amount of capacity. However, he added that IAB can also be used in low and mid-band 5G spectrum.
Stone said that Verizon has such a robust amount of mmWave spectrum that it can easily devote some of those resources to backhaul. “We don’t need full spectrum depth to serve our customers in an area,” he said. “We can use that additional bandwidth and provide backhaul.”
Moving from 4G to 5G is a big leap for network operators. It’s great to see that backhaul is finally getting some attention. Innovations are happening across all areas of the network – and adding IAB to the operator’s backhaul toolbox is likely to be a game-changer.