Without becoming reality, 5G mobile communications have already captured the imagination of operators and technology providers. So can the general public catch up with the hype soon? We’ll see. Meantime, behind-the-scenes mechanics of prepping for 5G continue, building on prior technologies. At each step of the evolution of backhaul infrastructure, different challenges cropped up.
With the goal of a hyper-meshed 5G street level network, clearly today’s small cell deployments represent just an interim phase in a progressive network densification—pushing the network outward. This means today’s small cell sites will become tomorrow’s macrocells, or hub sites.
Future-looking mobile operators have planned for this eventuality. In the developed world, small cell and the Internet of Things (IoT) drive mobile network densification. However, in the developing world the primary goal of enterprise connectivity spurs network densification, due to lack of wireline infrastructure to business buildings. The end result of network densification is the same.
As the telecom community searches for reasons why Small Cell architectures have not yet launched en masse, “experts” are quick to suggest that lack of backhaul technology as the key perpetrator.
The Case for Small Cell Backhaul
As the search for frequency bands with suitable capacity for small-cell backhaul continues, frequency bands above 50GHz start to appear attractive because they offer both high-bandwidth availability and short range owing to their inherent propagation characteristics. The white paper available at the bottom of this blog examines spectrum in the 57-64GHz range to see whether it can be of use for small cell backhaul.
In many countries, the frequency range 57-66GHz is split into a number of discrete bands with differing requirements and conditions of use and/or licensing. These differences will be highlighted where applicable.
From a global point of view, the use of this spectrum by Fixed Services (FS) is being addressed by the ITU-R in its draft report on Fixed Service use trends in WP5C, which is currently under development and states:
57 GHz to 64 GHz
The radio-frequency channel and block arrangements of these bands for FS are defined in Recommendation ITU-R F.1497.
In 2011, around 700 links were in use in this band in a few administrations. The majority of the links are used for fixed and mobile infrastructure.
The air absorption around 60 GHz is over 10 dB/km. This condition restricts the hop length; on the other hand, the spectrum reuse efficiency is high. This feature makes the band suitable for small cell mobile backhaul.
Clearly, a global reported usage of 700 links would suggest a great deal of underutilization, although with unlicensed use in many countries it is difficult to know whether these figures are accurate or not. Regardless, there are reasons as to why this could be the case, while noting that the ITU-R believes this band has potential for small cell backhaul.
One factor is that this spectrum is not allocated solely to the Fixed Service. In fact, in many countries the Fixed Services have no access to this spectrum at all. A more detailed country-by-country breakdown follows. Please sign up below to receive the entire white paper.
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Small cells get all the press! As LTE rolls out in networks on every continent except Antarctica, small cells are grabbing headlines in technology trades and geek fan-boy blogs across the Internet. They’ll be needed sooner or later to provide LTE access in all those places around corners of buildings on business campuses, in urban parks surrounded by concrete canyons and other inaccessible locations. But little or only passing thought is paid to the ways in which small cell traffic will be aggregated back to the main network.
However, in a new FierceWireless ebook, microwave backhaul is pointed out as one of the critical strategies to provide throughput for all the small cell traffic to come. Microwave was here before small cell. And it’s such a good fit for small cell, if it had not already existed, we’d have to invent it now! Our director of product marketing, Stuart Little, tells FierceWireless that microwave meets the capacity needs of LTE backhaul. And Fierce adds modern microwave technology is changing the perceptions of its use for small cell backhaul.
Neither sleet nor rain nor changing K factors at night will stop microwave from small cell service. Specifically, Little tells Fierce that rain has little to no effect on microwave at the lower frequencies, and where it does have some effect in the higher bands, different technical techniques can help mitigate it. To find out more about small cell microwave backhaul, we recommend any of the Aviat blogs and related articles below. Or just read the FierceWireless ebook.
With the mobile telecommunications space facing an onslaught of data-hungry subscribers and their migration to LTE, operators have embarked on a quest to pack even more service in smaller and smaller service areas. The frontier of these smaller service areas have come to be characterized as small cells. The issue is getting communications into and out of these small service areas. Capacity, coverage and interference all need to be addressed. Some have proposed serving small cells via Centralized Radio Access Networks (C-RAN). To implement a C-RAN, one of the requirements is a newer concept that has come to be termed “fronthaul.”
In a June 2013 meeting of the Telecom Council, Aviat Networks’ chief technology officer, Paul Kennard, took on fronthaul and the challenges it presents for LTE, small cell and C-RAN. In his presentation, he weighed the advantages and obstacles of fronthaul. While the chief advantage of distributing Remote Radio Heads (RRH) around the cell can help alleviate coverage, capacity and interference concerns, it is not easy to reach these RRH locations with fiber in the mostly urban areas where this deployment scenario will be needed most. This is especially true of non-traditional implementation of small cells on light standards, signposts and other non-tower infrastructure collectively known as “street furniture.” Wireless backhaul solutions will continue to be necessary in the grand scheme of things.
More is available on fronthaul in the Telecom Council presentation below as is in an associated webinar.
This week, Aviat Networks participated in the very well attended CTIA 2013 wireless and mobile trade show in Las Vegas. The theme for this year’s event was “THE Mobile Marketplace” with various areas of focus dealing with applications, devices and, of course, infrastructure. LTE, backhaul and small cells were once again important infrastructure-related topics during the event.
Aviat was a Platinum Sponsor of the Tower & Small Cell Summit—a sub-conference program composed of presentations, panels and case studies on wireless backhaul, mobile video, Distributed Antenna Systems (DAS), small cells, 4G and residential tower builds. I spoke on a panel at this event and shared our views on small cell evolution, including our thoughts on the migration of the mobile network to the Cloud Radio Access Network (C-RAN) architecture—if interested in this topic, please register for our upcoming webinars: North America or Europe, Middle East, Africa.
In addition, this show also paid significant attention to FirstNet—the nationwide public safety LTE network here in the United States. Aviat’s Ronil Prasad shared Aviat’s perspective on FirstNet, options for network sharing to reduce costs and best practices for building mission-critical backhaul networks for public safety LTE (with our 60-year history in public safety and our deployments in some of the largest LTE networks in the world, we are uniquely qualified to talk on this topic).
In addition, Aviat’s meeting facility experienced a constant flow of customers, industry analysts and partners, which kept Aviat staff on its toes for the entire event. Overall, it was a great show and Aviat was happy to participate to share our views on some of the most exciting new topics in mobile networks in the U.S.
Director, Marketing and Communications