AT&T, T-Mobile Agree on the Future of Small Cell

AT&T and T-Mobile recently filed comments with the FCC that will enable small cell backhaul in urban cores for greater subscriber connectivity.

AT&T and T-Mobile recently filed comments with the FCC that will enable small cell backhaul in urban cores for greater subscriber connectivity.

In the last few weeks, the future prospects of small cell antennas got brighter and shrank at the same time. AT&T and T-Mobile both filed comments with the Federal Communications Commission (FCC) in support of an industry-wide waiver of rules against flat-panel antennas for backhaul radios in the 70-80GHz bands. Currently, out-of-date FCC regulations about antenna radiation patterns hold back development and deployment of this type of equipment that urban dwellers will find acceptable in big city cores.

The current rules effectively call for the use of parabolic antennas that will be unsightly and would violate the aesthetics considerations and zoning regulations in many city core locations—precisely the type of environment that 70-80GHz radios exist to service. While the FCC regulations seem to necessitate parabolic antennas to keep radio beams focused and from interfering with equipment in the vicinity that uses the same wavelengths, mobile subscribers prefer more visually friendly solutions.

How to get from here to there
For the last few years, Aviat Networks has been working with the Fixed Wireless Communications Coalition and others to get the FCC to update its regulations in the 70-80GHz bands. The problem: when the FCC promulgated these rules, the idea had never occurred to anyone that these bands would ever service small cell applications. And the applications that the FCC’s 70-80GHz rules were designed to support never materialized, with only 5,500 links registered in this spectrum since 2005, according to T-Mobile.

However, with this breakthrough in support from Tier 1 operators like AT&T and T-Mobile, the FCC should feel reassured that granting the waiver to the antenna rules for 70-80GHz bands is in the best interest of all the wireless industry service providers. And with OEMs in addition to Aviat asking for the waiver, no specific vendor will be favored. We urge other wireless service providers, communications equipment OEMs, subscribers and anyone else interested in moving forward as fast as the technology can go to also contact the FCC about granting this industry-wide waiver.

In the meantime, to learn more about urbanized small cell backhaul in the 70-80GHz bands, download this white paper.

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Fishing for the Small Cell Red Herring

Fishing-for-Small-Cell-Red-Herring-Aviat-Networks-microwave-backhaul-blog-February-22-2014

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

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Wireless Transmission Blog 2012 in Review

Happy New Year and thank you to the avid readers of the Wireless Transmission Blog! We had readers from 186 countries (out of the official 192) during 2012! You’ll find other interesting statistics in the 2012 annual report WordPress has prepared below.

Here’s an excerpt:

4,329 films were submitted to the 2012 Cannes Film Festival. This blog had 40,000 views in 2012. If each view were a film, this blog would power 9 Film Festivals. Click here to see the complete report.

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Pole Sway and Small Cell Deployments for Wireless Backhaul

The two main vibration types for light poles are shown in figure 1.

The two main vibration types for light poles are shown in this figure. Both of these two vibration types will create sway that might affect the link performance for small cell microwave backhaul.

There is real concern from operators that utility, streetlight and traffic poles are not designed to meet the minimum twist and sway standards for deploying microwave solutions for small cell backhaul. Our research suggests that not all poles are created equal, however. Under certain circumstances these structures can be an option for deploying microwave backhaul for small cells.

Twist and sway requirements for towers and poles that support microwave backhaul hops are more stringent than for other RF equipment. This is especially true for deployments in frequency bands above 18 GHz where the antenna beamwidth is narrower than below 18 GHz. Standards such as the TIA-222-G set a minimum twist and sway that a structure should be able to endure for hosting a microwave installation. This creates concerns for operators interested in deploying microwave for small cell backhaul on structures including utility, streetlight and traffic poles that are not designed to meet this standard. Although the use of a sturdy structure is always recommended a close look at utility, streetlight and traffic poles suggests that under certain circumstances these structures can be an option for deploying microwave backhaul for small cell.

The installation of any equipment on existing poles—including small cell and backhaul radios and antennas—will necessarily change the weight and wind loading characteristics of the deployment pole. This will require a structural analysis to verify if the existing pole still meets the standards or the commercial criteria set by the pole manufacturer. For more information on Aviat’s analysis of pole sway for small cell backhaul see our PDF.

Eduardo Sanchez
Marketing Engineering Specialist
Aviat Networks

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Mobile World Congress 2012 Wrap Up

Aviat Networks Booth at MWC 2012¡Hola! again from the final day at Barcelona, where close to 1500 companies have been busily showcasing their products and services since Monday.

Once again microwave backhaul has featured highly with the main development being the widespread adoption of 1024QAM modulation. At least half a dozen new products now support this higher modulation level. Of course we are one of them, showing our new WTM 3200 all-outdoor radio. 1024QAM supports about 25 percent more throughput over the radio path compared to 256QAM, but it does come with a tradeoff in reduced system performance and increased interference sensitivity. These can be somewhat offset by using Adaptive Modulation, so if the link starts to struggle at 1024QAM it can drop back to a lower modulation until conditions improve.

Small cell backhaul has also been a hot topic, with many vendors jockeying for position in this emerging application. Small cells are tiny base stations that can be fitted to lamp posts or the sides of buildings, covering just a few hundred square yards/meters and would provide enhanced coverage and capacity to the network. There is talk of there being literally millions of these small cells being deployed over the next five years, starting in 2014 or so, and the big challenge will be backhauling all that traffic.

Multi-technology small cells (WiFi + LTE) are emerging to enable mobile offload directly at the outdoor mounted small cell. Offload solutions that offload traffic at the building and onto fiber/DSL are designed to relieve the RAN and backhaul networks. This approach however is designed to provide capacity relief to the RAN part of the network only and will use the same backhaul as LTE traffic. The intersection of mobile offload and outdoor mounted small cells will mean backhaul remains a critical part of the offload solution for some time to come.

As with last year, there is still a huge proliferation of new LTE-enabled smartphone and tablet devices. More connections bring more opportunities. This is good for our business as mobile operators will need to upgrade their networks.

Until next year!

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