Published on April 15, 2020
You've probably heard a lot about 5G and its supporting optical access networks, but you may be wondering about the practical details of full-scale deployment and whether costs will make it unfeasible. Those are reasonable concerns, and from EXFO’s perspective, there are answers to be found. Dense wavelength division multiplexing (DWDM) has the potential to make 5G wireless access networks more affordable, leveling out overall 5G CAPEX and OPEX costs and accelerating deployment. EXFO’s Maury Wood, Business Development Manager of North American Key Accounts, recently shared some insights on this topic on an episode of EXFO's "Test Your Network" podcast.
In 2019, all four major US wireless carriers began to offer 5G services and are continuing to expand coverage areas. But deployment has been slowed due to cost concerns, with challenges surrounding the expansion of the optical fiber edge networks that feed 5G radio base stations and small cells. Historically, there have been two ways to do this. "There are limited ways to expand the access bandwidth for 5G. Bury or string more cables, which is expensive – you have the cost of the fiber and installation labor, but also the time component of environmental and community impact assessments, especially in dense urban areas,” Wood said. “The second relatively new and exciting option is to leverage DWDM technology in the access network transmission equipment." To understand how DWDM can create a cost advantage, it's important to know how it works.
DWDM technology has been around for decades. An easy analogy that Wood uses–it works in the same way that our ears hear music. "The beautiful thing about sound is that our ears are able to simultaneously hear low-pitched and high-pitched sounds, which helps to explain why music is so beautiful to most of us," Wood said. "The same basic principle applies with light traveling through the atmosphere to our eyes, or laser light going through glass fiber. The wavelengths do not mix and can be separately encoded and decoded for higher aggregate information content." DWDM narrowly slices the optical spectrum so that each wavelength can transport different data streams, and DWDM signals can be recovered at great distances using optical amplifiers. You then don't need more optical fibers, just the ability to utilize different wavelengths on a single existing (and fully cost depreciated) fiber.
Practical DWDM systems in the past were stymied by low volumes and high costs, and were used mainly in core networks. While mobile carriers understood that DWDM was a technology worth exploiting to increase access network fiber bandwidth, they didn't want to make this investment for lower bandwidth 3G and 4G LTE deployments.
Now a major shift in component cost and functionality, in the form of high volume 400G coherent photonic integrated circuits as embodied in the new 400ZR IA from the OIF, is enabling the upgrade of fronthaul and backhaul transmission equipment to DWDM technology, just in time for full-scale 5G wireless services deployment.
This leap forward is bolstered by EXFO's 5G test solutions, which automate and streamline field operations in 5G xhaul and transport deployments, facilitating the transformation to 5G infrastructure. With this emerging DWDM-based access network transmission equipment, existing fibers can multiply their wavelength capacities up to 100-fold on a single fiber, delivering the bandwidth over existing outside plant fiber runs needed for fully scaled-out and ubiquitous 5G wireless services.
Consumer and industrial demand for 5G services will continue to grow, putting pressure on carriers to deliver on their commitments. This challenging worldwide deployment can be made much smoother with the right tools.
Explore how our 5G test solution for mobile networks can do just that.