"microwave communications" posts

Fishing for the Small Cell Red Herring

• February 21, 2014
• 70GHz, 80GHz, backhaul, densification, E-Band, microwave communications, microwave congestion, millimeterwave, small cell, small cell backhaul, small cells, urban backhaul, urbanized backhaul

Photo credit: Foter / CC BY-SA

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.

As I wrote in a 2013 article, starting with wireless microwave communications (6-42GHz frequency range), solutions for backhaul both large and small are available and effective today for mobile operators.

This is the second in a series that highlights technology available to enable immediate deployment of small cell backhaul. This segment focuses on the convenience of using wireless E-band as a complement to microwave for small cell backhaul, while bringing to light some of the true obstacles to small cell adoption.

E-band is a part of the electromagnetic frequency spectrum in the millimeter range between 71-76 GHz and 81-86 GHz. In recent years, there has been more interest in this frequency band, because traditional microwave (6-40 GHz) bands are now very congested in parts of the world, and that with the densification of mobile networks due to the introduction of 3G/HSPA and 4G/LTE, link distances between cell sites are shrinking in urban areas.

The surge in interest in a new network of outdoor small cells is driving a new approach toward cost-effective wireless solutions for backhaul. E-band offers a large swath of available spectrum with more than 10 GHz at stake—it represents more bandwidth than all the combined open frequency bands below 40 GHz.

What is needed is an all-outdoor, packet millimeterwave radio, offering a rich set of features, expressly built to support mobile (macro and small) backhaul by:

• Conforming to planning and local authority “community-friendly” aesthetics and design approval guidelines
• Eliminating external parabolic antennas, thus enabling significant savings on shipping, storage and handling costs
• Weighing dramatically less than competing solutions, resulting in easier handling and installation within 30 minutes
• Consuming less power, allowing flexibility in electrical source options such as via fixed supplies or Power over Ethernet (PoE), with built-in surge protection

As the world becomes increasingly urbanized—for the first time ever, more than 50 percent of the world’s population lives in dense urban areas—it is also the place where we communicate the most and networks are most stressed to keep up. Small cell designs offer a convenient method to densify networks.

However, my prediction is that in the near to medium term, deployments will be surgical—to plug gaps where coverage is poor and to fill hot-spots where incremental capacity is needed. It is important to note that outdoor, public access small cells will coexist and in some ways compete with other densification solutions, including DAS, wi-fi, and additional macro cell builds. Small cells may indeed need to be backhauled from light poles and building sides, but ultimately they need to go where they need to go, while serving the primary goal of not-spot and hot-spot filler.

The more pressing obstacles for outdoor small cells include the method operators use to assess the business case and solve the construction and site acquisition challenges borne by the paradigm shift. The expectation is that the ecosystem will produce a solution that makes small cells easier and cheaper to deploy than macro cells. The problem with that thinking is the economics of it all. The business case will continue to struggle to prove out vs. macro cell, as scalability and network dimensioning quickly come at odds with requirements for unbridled capacity, high reliability and network intelligence.

Operators think they may be vying for a diminutive device supporting multi-generational, multi-band, multi-media and multi-OSI-layers, but that utopian requirement breeds complex challenges in permitting, site acquisition, interference, costs, and so on—all items recently in the pick-list of a flash poll by Light Reading. I maintain that we are not just over-thinking, but over-expecting the benefits of a pure-play small cell rollout. We might all be better off following the “K-I-S-S” principle for the foreseeable future, which might produce this guidance:

1. Use small cells only where it makes sense
2. Deploy it with tried and true technology (i.e., wireless microwave)
3. Consider E-band for expansion in dense urban outdoor environments
4. Be mindful about keeping your budget in the black, but don’t stress about challenges that need not manifest in your business

So here’s to Keeping it Small and Simple!

Louis Scialabba
Senior Manager of Marketing
Aviat Networks

Related articles

• Big Promise for Small Cell Mobile Backhaul (aviatnetworks.com)
• Critical Role of Microwave in LTE and Small Cell Backhaul (aviatnetworks.com)
• THE Mobile Marketplace: Towers, Small Cells and Backhaul (aviatnetworks.com)
• If Microwave Didn’t Exist for Small Cells, We’d Have to Invent It! (aviatnetworks.com)

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