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 Currently, out-of-date FCC regulations about antenna radiation patterns hold back development and deployment of this type of equipment that urban dwellers will find acceptable in big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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Telecom Industry Participants call on FCC for E-band Action

While U.S. regulators decide on flat-panel antenna rules for E-band, operators and subscribers walk a tightrope of red tape.

While U.S. regulators decide on flat-panel antenna rules for E-band, operators and subscribers walk a tightrope of red tape.

Back in April the telecom experts over at CommLawBlog weighed in on a simmering issue in the 70-80GHz radio space. Since October 2012, the Federal Communications Commission (FCC) has mulled over a motion by the Fixed Wireless Communications Coalition (FWCC) to relax rules for flat panel antennas as well as a 2013 waiver to the existing rules while it considers a new rulemaking.

Lack of taking any action on any of these filings has left the backhaul industry in a quandary. With viable radio solutions ready to deploy in the 70-80 GHz frequency ranges, the only holdup has been a technical requirement that FCC rules place on the radiation pattern of the very thinnest of flat panel antennas. These rules were originally formulated for an era where microwave radios were used for links that spanned 1 to 5 kilometers.

In the new urban reality for small cells, the distances between mobile base stations will be measured in hundreds of meters. At these lengths, the radiation patterns of flat panel antennas will not materially increase interference, to paraphrase language the FCC itself has used previously when approving use of smaller antennas in the 6, 18 and 23 GHz bands, circa 2012.

With small cell wireless in close-in city settings, both mobile and non-mobile subscribers have a heightened sense of awareness, and they will take extra notice of backhaul radios with prominent parabolic dishes that stick out like sore thumbs. With their figurative and literal low profiles, flat panel antennas provide the critical missing link in ameliorating the aesthetics concerns that many feel toward old, bulky microwave installs. While these hulking communications devices were fine on towers at long haul sites way out by the interstate freeway or high atop skyscrapers in the heart of the business district, when they are situated on the side of a residential building the modern-day urbanite will not tolerate these telecom equipment eyesores.

In reality, there is very little for the FCC to decide upon. While the telecom regulator here in the United States has its own rules, regulators in much of the rest of the world use the ETSI standards. Actually, the standard in effect is of little consequence. The point of fact is that the flat panel antennas in question before the FCC have been approved for use in all these ETSI countries without any significant drawbacks being reported in nearly three years of use. Even the FCC’s companion agency to the north, Industry Canada, has given tentative go-ahead to flat panel antennas for use with 70-80GHz backhaul radios, with the implicit understanding that they will receive formal approval if no unforeseen snags occur in final rule drafting.

So while the rest of the small cell community enjoys a flat panel world, the U.S. is walking a tightrope of red tape in hopes that some decision is made—soon.

Full disclosure: Aviat Networks is the filer of the 2013 waiver request and is a member of the Fixed Wireless Communications Coalition. Aviat Networks is legally represented by Fletcher, Heald & Hildreth, PLC, the host of CommLawBlog.

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FCC: New Spectrum for Wireless Backhaul, Relaxed ACM Rules

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On 9 August 2011, the FCC announced several changes to the rules (Part 101) that govern the use of microwave communications in the Fixed Service bands in the U.S. These changes are great news for operators and will be encouraging increased adoption of microwave technology as a wireless transmission alternative to fiber for next generation mobile networks and fixed/private networks.

New Frequency Band for Fixed Services

The FCC opened 650 MHz of new spectrum for Fixed Service (FS) operators in the 6875-7125 MHz and 12700-13100 MHz bands, which will be shared with the incumbent Fixed and Mobile Broadcast Auxiliary Service (BAS) and Cable TV Relay Service (CARS). These bands will primarily be used as an alternative to the 6 and 11 GHz “Common Carrier” bands in rural areas, where the band is not currently licensed to TV mobile pickup stations used in newsgathering operations.

Frequency allocations in these new bands should commence later this year and will be based upon the existing 25MHz channelization. To facilitate adoption, the FCC is also allowing the use of 5, 8.33 and 12.5 MHz channels, as well as 50 MHz channel operation in the 12700-13100 MHz band using two adjacent 25MHz channels.

Allowing Adaptive Modulation

Adaptive Modulation, or AM—or ACM when used with Adaptive Coding—is a relatively recent innovation in microwave technology that allows the radio to dynamically adapt to path conditions to allow a much higher degree of spectrum efficiency, increased wireless link throughput, use of smaller antennas or a combination of all three benefits.

Up until now, the use of AM was restricted by the requirement to comply with FCC spectrum efficiency rules, which dictate a minimum data rate for certain bands. For example in the 6 GHz band a minimum capacity of 130 Mbit/s, or 3xDS3, must be maintained at all times within a 30 MHz channel assignment, using 64QAM modulation. The FCC now allows AM operation where the capacity of the link may drop below the minimum data rate, as long as the operators “design their paths to be available at modulations compliant with the minimum payload capacity at least 99.95 percent of the time,” or in other words, operators will have to “design their paths to operate in full compliance with the capacity and loading requirements for all but 4.38 hours out of the year.”

Aviat Networks, through our membership of the Fixed Wireless Communications Coalition (FWCC), supported rule changes to permit ACM, and the FCC included in its Rulemaking (Clause 48) our analysis on the benefits of ACM in terms of reducing the costs associated with tower leasing:

By way of hypothetical, consider a single link in the 6 GHz band that would require 10-foot antennas with a 99.999 percent standard instead of 6-foot antennas under the 99.95 percent standard. The total cost increase over a 10-year period in this hypothetical example could exceed $100,000.

The smaller antennas offer a number of advantages over larger ones, including more TCO savings over those 10 years.

Still Under Consideration by the FCC

Of all the new proposals being considered, the FCC also announced a Further Notice of Proposed Rulemaking (FNPRM) to further investigate the following proposals:

  • Allowing Smaller Antennas in Certain Part 101 Antenna Standards without materially increasing interference
  • Exempting Licensees in Non-Congested Areas from Efficiency Standards to allow operators to increase link length in rural areas
  • Allowing Wider Channels, including 60 MHz in the 6 GHz band, and 80 MHz in the 11 GHz bands
  • Revising Waiver Standard for Microwave Stations Near the Geostationary Arc to align with ITU regulations
  • Updating Definition of Payload Capacity rules in Part 101 rules to account for Internet Protocol radio systems

Aviat Networks continues to work on these issues, via the FWCC, which we believe will assist operators in lowering their total wireless network operational costs by taking advantage of the newest innovations that are now available in microwave technology.

With these new rules, along with the potential for further changes under consideration, microwave solutions provide an even more compelling case to enable mobile operators in the U.S. to keep pace with the IP mobile backhaul capacity demand driven by the introduction of new 4G wireless/LTE wireless networks.

Ian Marshall
Regulatory Manager, Aviat Networks

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Antennas: Why Size is Important for This Wireless Equipment

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In response to the recent FCC docket 10-153, many stakeholders proposed relaxing antennas requirements so as to allow the use of smaller antennas in certain circumstances. This is an increasingly important issue as tower rental costs can be as high as 62 percent of the total cost of ownership for a microwave solutions link. As these costs are directly related to antenna size, reducing antenna size leads to a significant reduction in the cost of ownership for microwave equipment links.

The Fixed Wireless Communications Coalition (FWCC), of which Aviat Networks is a major contributor, proposed a possible compromise that would leave Category A standards unchanged while relaxing Category B standards. The latter are less demanding than Category A, and after some further easing, might allow significantly smaller antennas. The rules should permit the use of these smaller antennas where congestion is not a problem, and require upgrades to better antennas where necessary.

A further detailed proposal from Comsearch proposed a new antenna category known as B2, which would lead to a reduction in antenna size of up to 50 percent in some frequency bands. This would be a significant cost saving for link operators.

At the present time, the industry is waiting for the FCC to deliberate on the responses to its 10-153 docket, including those on reducing antenna size.

See the briefing paper below for more information.

Ian Marshall
Regulatory Manager, Aviat Networks

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