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One of my favorite industry expressions is “there are a lot of wires in wireless.” I recall first hearing this expression around 10 years ago at a presentation given by a wireless operator in South East Asia, and those of you that have heard me talk at conferences would know that this is a term that I continue use on a regular basis.
The explosive and seemingly insatiable growth in mobile data traffic has made fiber the backhaul connectivity of choice to serve not only today’s requirements, but also to meet the following expectations that 5G promises:
- Up to 10Gbps per subscriber
- Up to 100 x connected devices
- 1000 x more bandwidth
- 5 x location density
- Ultra low latency less than 5 milliseconds
In order to reduce power usage and optimize space utilization at the tower, many operators are now transitioning to centralized RAN (C-RAN) architecture—and here, too, fiber is playing a key role by providing the fronthaul connectivity between the centralized broadband base unit (BBU) and the remote radio head (RRH) located at multiple cell sites many miles away.
C-RAN offers an effective way to increase the capacity, reliability and flexibility of the network while lowering operational costs. It is also a necessary step along the path to cloud RAN, where the BBU functionality will become “virtualized”—allowing for greater elasticity and scalability for future network requirements.
Network operators that have invested in fiber-to-the-home (FTTH) networks over the past 20 odd years have unwittingly been laying the foundation for 5G. Most FTTH networks today are using just two or three wavelengths – one for gigabit passive optical network (GPON) downstream, one for GPON upstream, and one for video overlay. The vast spectrum of Coarse /Dense Wavelength Division Multiplexing (C/DWDM) wavelengths remain unused, and hence can be utilized for wireless applications.
These network operators can use the same fiber strand but keep cell site traffic and residential GPON traffic on different wavelengths. Passive C/DWDM modules are put at both ends of the fiber to combine/separate the different wavelengths. Alternatively, you can keep traffic on separate fiber strands and design the connectivity at the hubs and closures to appropriately route the traffic.
An additional driver for more fiber will be 5G fixed wireless access, which is being utilized by some operators as another option for delivering broadband to consumers in their homes and small businesses. Whilst fixed 5G broadband access will be quicker and simpler to deploy than FTTH, the rate that bandwidth can be turned up is accelerated, which will exacerbate bandwidth pressures on all parts of the network. This means that more and more fiber will be required in order to handle this.
Essentially all metro, long haul, and trans continental networks today are fiber-based, and they have proven that they can scale to meet the growth in bandwidth by utilizing the latest generation of optical transmission technologies. The access network though still has a significant amount of copper, wireless and microwave technology deployed. Areas targeted for 5G coverage require lots of fiber to be successful, and not just for capacity reasons. It must also meet other rather formidable 5G performance goals related to network diversity, availability, and coverage since all three of these goals are achieved through a greater number of interconnected paths of fiber.
In order to achieve the performance goals promised by 5G, the adage “lots of wires in wireless” is stronger every day — and those wires are fiber.
By Wes Oklee, director of Business Development and Strategy for the CommScope Connectivity Solutions
October 12, 2018