We Put the Spotlight on Voice Over LTE (VoLTE)

As one of the most anticipated network technologies, Voice over LTE (VoLTE) has been discussed by operators for years. The expectation was that deployments would start in 2013, but roll-outs in North America were delayed.

VoLTE Logo

Logo courtesy of YTD2525 Blog

Operators have faced a series of issues that include poor voice quality and long call establishment times. Once these problems are solved, it is expected that VoLTE will allow operators to provide  voice and data services using an integrated packet network. As the problems described show, the implementation of VoLTE presents challenges for the entire LTE ecosystem including microwave backhaul.

We have produced a white paper to describe some of the VoLTE requirements that must be met in order to overcome these technical challenges, which must encompass a flexible microwave backhaul as a key factor for a successful transition to all-packet voice and video VoLTE  networks. A brief introduction to VoLTE is presented and then different VoLTE backhaul requirements are described with possible solutions.

Click here to download a white paper on this subject titled “VoLTE and the IP/MPLS Cell Site Evolution”.

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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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More on E-band Backhaul: a Tale of Two Operators

Tight city spaces will need small E-band radios for microcell backhaul. Photo credit: La Citta Vita / Foter / CC BY-SA

Tight city spaces will need small E-band radios for microcell backhaul. Photo credit: La Citta Vita / Foter / CC BY-SA

The last time we were together, we discussed the prospects for urban backhaul in 2014. True, it will be a very exciting time in the 70 GHz and 80 GHz E-band frequencies. The promise of small cells is finally coming to fruition after the hype cycle had all but chewed and spit them out. Remember when you first heard of DSL and cable modem? By the time you could get one, the media had stopped talking about them for at least two years. But we’re digressing.

The point is that with cellular network subscribers actually able to connect to these microcell base stations, the need for a viable backhaul solution has come to a head. E-band to the rescue! And the need is not just with the established players to extend their mobile networks into the city cores backed by radio backhaul. By opening up the 70 and 80GHz frequencies to commercial backhaul applications, regulators have created an opportunity for new market entrants to move under the radar and grab share from the legacy carriers, who had previously discounted this spectrum.

With very aggressive pricing and novel tariffs that offer a bare minimum of 50 MB for data downloads and two hours of airtime for the equivalent of less than 3 dollars/month, as an example from Aviat research, a provider of mobile services such as these would need to be very creative capitalizing its backhaul requirements. As it turns out, on a per-link basis, an 80GHz nationwide backhaul license can be had for less than if the operator bought individual licenses everywhere it provides coverage—in one nation, in any event. At least, it would be true once a provider’s backhaul sites pass into four-figures territory.

Nonetheless, it’s a remarkable development made possible by the world shrinking figuratively and people living in closer quarters as never before. Brought to you by (the letter) E-band backhaul!

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Urban Backhaul with 70-80GHz E-band Radios

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Urban infrastructure for E-band radio. Photo credit: christine592 / Foter.com / CC BY-ND

For years and years, microwave and millimeterwave radio technologies have coexisted without very much overlap in either their markets or applications. Microwave radio served telephone company needs (e.g., long distance backhaul, mobile access aggregation) for the bulk of its implementations with some vertical deployments for oil and gas, public safety and utilities organizations. Typically, licensed bands in service ranged from 6GHz to 42GHz—with 11GHz and under popular for long haul; 18-38GHz trendy for short urban hops. Generally, millimeterwave radio is considered to be between the 60GHz and 80GHz bands and found its applications confined to those for intra-campus communication from building to building for universities, civic centers, other government conglomerations and large, spread-out (i.e., 1 to 5 miles) corporate facilities.

More recently, E-band has seen its profile rise, as mobile operators have had to “densify” their networks to service the more tightly packed populations moving into larger and larger cities around the world. This is due to at least two factors: the shorter distances between wireless sites in urban locations and the lack of available spectrum in the traditional microwave bands. E-band radios are now starting to be deployed to aggregate traffic from macro cell base stations in the Gotham-esque landscapes of the 21st century and the new small cell transceivers that venture where no full-size mobile base station can tread.

So into this brave new world of urban backhaul, next-wave E-band radios have been thrust. But small form-factors and spectrum availability are not going to be enough to ensure the success of this new generation of millimeterwave equipment. Additional features will be necessary. They will need capabilities such as:

  • Integrated antennas to enable quick installation, minimize visual impact on city dwellers and overall promote “community friendly” backhaul
  • Light weight for lessened load factors on light poles, street signs and other non-traditional metro wireless infrastructure
  • Wide channels up to 250MHz in size
  • Scalable capacity starting at 350 Mbps to 1 Gbps with room to grow

It is an exciting time in the E-band space in early 2014. We will share more as the year progresses. Check back regularly to stay apprised of developments.

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60GHz Band: a Solution for Small Cell Backhaul?

60GHz-microwave-backhaul-could-be-effective-solution-for-small-cell-if-regulators-in-various-nations-permit-its-use-says-Aviat-Networks-07Oct13

Small cell will enable mobile usage in dense urban environments but will need a backhaul solution to make it possible. Photo credit: Ed Yourdon / Foter / CC BY-SA

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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Ian Marshall
Regulatory Manager
Aviat Networks

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A (Personal) Milestone in Microwave Networking

aviat-networks-senior-network-engineer-shares-his-first-microwave-radio-path-plan-on-28th-anniversary-with-the-company-Ivan-says-I-am-showing-the-first-studio-transmitter-link-STL-design-I-did-in-January-1986-for-a-broadcaster-in-Louisiana-while-working-as-a-Proposals-Engineer-for-Harris-Broadcast-Microwave-in-Mountain-View-CA-The-antenna-heights-were-around-600-ft

Figure 1: Aviat Networks’ senior network engineer Ivan Zambrano shares his first microwave radio path plan on the occasion of his 28th anniversary with the company.

Recently, Aviat Networks was privileged to mark a milestone for one of its longest tenured and most distinguished employees, Ivan Zambrano. For 28 years, Ivan has dedicated his professional life to providing education and expert analysis to the microwave backhaul community, on the behalf of Aviat Networks and its corporate predecessors. As a senior engineer, Ivan teaches network transmission courses and other topics around the world on a regular basis.

However, Ivan got his start in the field. In fact, he still has the very first microwave radio path plan he ever created for a television station in Louisiana (Figure 1).

Together with the legendary Dick Laine (Figure 2), the two veteran microwave communications professionals have a combined 97 years of experience in the field. Unbelievably, Ivan actually has seniority over Dick (in the company at least). Dick has only been with us for a mere 26 years!

Between-Aviat-Networks-Dick-Laine-left-and-Ivan-Zambrano-right-the-two-microwave-radio-path-planners-have-97-years-experience-13Sep13

Figure 2: Dick Laine (left) and Ivan Zambrano have a combined 97 years of microwave experience.

To help celebrate the occasion, Aviat Networks CEO, president and board member Michael Pangia took some time to personally congratulate Ivan (Figure 3). So here’s to you Ivan! We’re all looking forward to at least another 28 years!

Aviat-Networks-CEO-president-and-board-member-Michael-Pangia-personally-contragulated-Ivan-Zambrano-on-his-28-years-with-Aviat

Figure 3: Aviat CEO Michael Pangia and Ivan.

If you’d be interested in having Ivan or Dick lend a hand (or bend an ear) on your microwave project, let us know by dropping a note below. Give us an idea about the type of training or consultation you need and any other pertinent details about the project.

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Top Trends in Backhaul Summer 2013

Ryan-Bruton-Aviat-Networks-senior-international-marketing-manager-sees-big-trends-against-fiber-and-for-microwave-in-backhaul-in-summer-2013

Ryan Bruton: Aviat Networks senior international marketing manager.

As the summer in the Northern Hemisphere quickly draws to a close, we can look back to the beginning of the season to see what was on the mind of the backhaul market. Our international marketing manager, Ryan Bruton, gave an interview to CommsMEA covering the trends in backhaul for this time period.

In microwave backhaul, for the African market, radio links are averaging around 40 kilometers in length, says Bruton. This is due in part to climatological conditions, but other factors could also be involved, he says. However, in the Middle East, the typical microwave backhaul links are above this average—also partially due to the atmosphere and geography.

Another big trend Bruton sees this summer in backhaul includes the barriers to fiber being used in the Middle East and Africa markets. Accordingly, fiber is very difficult to trench over kilometers and kilometers of open desert. The terrain is inhospitable and very tough on fiber due to high heat and arid conditions. Not to mention bringing in the equipment necessary to install long fiber routes can be a very large obstacle if the paths lay some distance away from existing roads and other infrastructure. Going through the lush flora of Africa, such as in Nigeria, trenching fiber presents a different yet also nearly insurmountable set of barriers, with massive stands of sometimes-centuries-old trees. And clearcutting tropical rainforest to make way for a fiber backhaul route is neither cheap nor “green.”

Microwave is both the more cost-effective and greener alternative compared to fiber-optic technology for wireless backhaul. Currently achieving about 50 percent of the total market share for backhaul worldwide, microwave certainly is a driver for mobile and other wireless network operators.

Then there is always the potential for fiber to fall victim to so-called “backhoe fade,” a euphemism for the accidental cutting of fiber lines by misguided digging operations. But there is always the potential that fiber cuts are not accidental. In any event, fiber is vulnerable to cuts over the entire course of a route—from Point A to Point B. Microwave sites are isolated to a single spot where they may be assailable. At least operators have the option of “hardening” their microwave sites for maximum uptime, whereas, again, this would be too cost prohibitive in the case of fiber over an entire route.

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Lessons of LTE Africa 2013: Bringing Broadband Back to Basics

Cell tower with microwave: many lessons were taught and learned at LTE Africa, Aviat's Siphiwe Nelwamondo reports.

Photo credit: Jeff Kubina / Foter / CC BY-SA

Africa’s only dedicated LTE event, LTE Africa 2013, took place in Cape Town this July 2013, bringing operators, vendors, mobile device makers, regulators and standardization bodies together under one roof to discuss LTE. On the agenda were the opportunities LTE can bring, obstacles to deployment, monetization challenges, current African success stories and future directions that LTE may take in Africa.

At the conference, operators grappled with the opportunity they face with LTE. What emerged as the main challenges for operators were spectrum, monetization and device availability—at the right price—for the African market.

In many exchanges, policymakers and regulators were beseeched to make spectrum available for LTE. Dr. Ernest Ndukwe, former CEO of the Nigerian Communications Commission, said, “Unless African leaders create an environment which encourages broadband network investments and makes it easy for companies to roll out broadband services, the situation is unlikely to change in the near future.” Operators were equally concerned about monetization of LTE so as to be able to recover their CAPEX—not to mention OPEX. (Others have not fully recovered their investments on 3G yet!)

Nonetheless, they are now expected to move to LTE. It was clear that operators would need to innovate how they do business by implementing new pricing strategies such as “value bundling” solutions, which would move them away from the cost-per-megabyte pricing tariff they firmly cling to today. Finally, a mobile device priced correctly for the African market has been earmarked as the enabler needed for massive adoption of LTE in Africa.

However, the conference was not all gloom and doom as operators who have successfully implemented LTE, such as Smile, MTC and others, shared information on how they made it possible. They highlighted how they implemented LTE. One of the key areas they focused on was in what way they backhaul LTE traffic.

Successful implementations revealed that for Africa—considering Africa’s demographics—practical and cost-effective implementation of LTE does not allow for 100 percent fiber backhaul, especially since realistic throughput demands of a typical three-sector LTE site max out at about 150 Mbps. With microwave systems easily able to reach 400 Mbps and even 2Gbps, microwave is more than capable of catering to an LTE site’s requirements and is undoubtedly the technology of choice for LTE backhaul except at sites where fiber already exists.

Microwave has cost benefits when deploying in areas lacking fiber, and it can be a cost-effective way to connect rural areas. Microwave also has the benefits of being quicker-to-deployment compared to the trenching needed for fiber. By 2017, industry analysts foresee that microwave backhaul will account for more than 50 percent of all LTE cell sites in Africa.

Siphiwe Nelwamondo
Technical Marketing Manager, South Africa
Aviat Networks

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85 Microwave Operators tell us their Biggest Backhaul Challenge

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England: Campion Hills communications mast with microwave antennae. Photo credit: David Stowell [CC-BY-SA-2.0], via Wikimedia Commons

The general mobile industry sentiment has typically been that the capacity bottleneck is the biggest challenge in backhaul. Thus, the focus has been on adding more capacity to address the surge of 3G and now 4G traffic. So you might think that this concern would rank first, particularly among microwave-centric operators, who are often looking to maximize their network throughput. We recently commissioned the experts at Heavy Reading to do a custom survey to get some quantifiable data to clarify this key question and a few others.

85 mobile operators were selected and surveyed globally, including a good cross-section from both developed and emerging markets. The respondents were screened to ensure that they all had a stake in microwave-specific backhaul: 93 percent had deployed microwave and the rest had plans to deploy it. In fact, 45 percent were categorized as heavy microwave users—those where more than 50 percent of their cell sites were served by microwave backhaul.

So we asked this select group, which consisted of mostly planners, engineers and strategy leaders, “What is the biggest challenge your company faces regarding the future development and deployment of microwave backhaul?” 

The results were interesting in that “total cost of ownership” actually eclipsed “increasing capacity” as their biggest challenge, as shown in the pie chart of survey responses below.

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LTE Backhaul: The View from Africa

Telecom-tower-Johannesburg-South-Africa-enabling-LTE-backhaul

Telecom Tower, Johannesburg, South Africa. Photo credit: Marc_Smith / Foter / CC BY

LTE has been moving more and more to the forefront in mobile cellular networks around the world. Africa, and particularly the Republic of South Africa, is the latest hotbed of LTE rollouts, with the leading country operators of Vodacom, MTN and Cell C coming online since late in 2012. In conjunction with these LTE access rollouts, our technical marketing manager in the region, Mr. Siphiwe Nelwamondo, has been authoring a series of columns on enabling LTE in a leading regional technology media Internet site, ITWeb Africa.

Naturally, his focus has been on backhaul. In the first installment of his series, Mr. Nelwamondo looked closely at the backhaul requirements of LTE. Chief among these requirements are speed, Quality of Service (QoS) and capacity. He concluded that it is too early to close the book on the requisite parameters for supporting LTE backhaul. Part two of the features, he examined the basis on which microwave provides the technical underpinnings for LTE backhaul—especially as related to capacity. More spectrum, better spectral efficiency and more effective throughput were Mr. Nelwamondo’s subpoints to increasing capacity.

Having more spectrum for microwave backhaul is always nice, but it’s a finite resource and other RF-based equipment from satellites to garage door openers is in competition for it. Bettering spectral efficiency may be accomplished by traditional methods such as ACM and might be increased through unproven-in-microwave techniques like MIMO. Throughput improvement has wide claims from the plausible low single digit percentage increases to the more speculative of upping capacity by nearly half-again. Data compression and suppression are discussed. The truth is LTE, while data-intensive, probably will not require drastic measures for backhaul capacity until at least the next stage of LTE-Advanced.

If indeed capacity increases are necessary in the LTE backhaul, number three and the most current piece of Mr. Nelwamondo’s contains additional information. Nothing is better than having something bigger than normal or having many of the standard model. As the analogy applies to LTE microwave backhaul, bigger or wider channels will increase capacity, of course. A larger hose sprays more water. Or if you have two or three or more hoses pumping in parallel that will also support comparatively more water volume. The same is true of multiple microwave channels.

However, the most truly and cost effective capacity hiking approach is proper network planning. Mr. Nelwamondo points out that in Africa—more than some places—mobile operators are involved in transitioning from TDM planning to IP planning. While TDM planning was dependent on finding the peak traffic requirement per link, IP planning allows the flexibility to anticipate a normalized rate of traffic with contingencies to “borrow” capacity from elsewhere in a backhaul ring network that is not currently being utilized. Along with several other IP-related features, this makes determining the capacity a lot more of a gray area. Some operators solve this by simply “over-dimensioning” by providing too much bandwidth for the actual data throughput needed, but most cannot afford to do this.

The fourth and final entry in Mr. Nelwamondo’s series will appear soon on other LTE backhaul considerations of which you may not have thought. Sign up below to be notified when it is available. [contact-form-7 404 "Not Found"]

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