Hardware Design

Ciena And Aviat Team Up On Unified Fiber-Microwave Solution For Utilities
Building advanced utility communications networks requires a solution with superior performance that spans both fiber and microwave to meet the wide variability in terrain while improving overall cost and reliability.

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- October 18, 2017
Evolution of Trunking Microwave Radios
Aviat WTM 6000 trunking microwave radio
Back in the day, trunking microwave radios were huge power-hungry beasts that consumed vast quantities of power and space at equal rates. They were complex “animals” that took days to install and hours to configure. Then they had to be looked after like well-loved but aged members of the family—with care, all due respect and consideration. Over time, components went out of adjustment and had to be brought back into line through various tuning routines, but overall they did their job as the super-reliable backbone of the POTS (i.e., Plain Old Telephone Service).
Jump forward a few decades and the latest trunking microwave solutions are elegant and graceful—almost svelte. With their current high levels of electronic integration, a complete repeater system can stand in a single rack space—unheard of until the most recent products. Furthermore, these new systems consume dramatically less power—a typical 3+1 system (i.e., four transceivers) consumes less than 400 watts. So now, backbone operators can save significantly on operating expenditure because of decreased space and power requirements at their microwave radio shelters.
Evolving microwave systems from analog to digital microwave systems carrying digital payloads was a rocky and dangerous path. The next migration from TDM payloads to IP payloads appears to be just as treacherous. How can a traditional TDM backbone radio, typically configured with N+1 radio protection switching, be reconfigured to transport a non-TDM payload that does not suit N+1 switching? IP transport is a completely different environment altogether! Luckily, trunking radio system designers have not ignored the Internet revolution and are perfectly aware of these challenges. In fact, well-appointed trunking microwave radio systems allow a graceful evolution from TDM to IP, with capability to transport both types of traffic simultaneously—and with their own ultra-reliable protection schemes!
Today, trunking microwave radios can support both TDM and IP seamlessly, offer robust radio performance and highly reliable switching and really do make it easy for operators to design mission-critical backbone networks. They offer mean time between failure (MTBF) reliability figures into the hundreds-of-years and highly integrated yet modular designs, which make expansion very straightforward. Before deciding on a trunking microwave radio, consider if the system:
- Allows easy migration from TDM to IP with a minimal amount of replacement materials
- Can expand to an expected maximum channel capacity (for example, six channels) without needing additional racks, etc.
- Enables repeater configurations within one rack
- Has a field-proven heritage of reliability and performance
Terry Ross
Senior Product Manager
Aviat Networks
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- October 2, 2012
All-Indoor Microwave: LTE’s Best Backhaul Solution for North American Operators
Aviat Networks’ Packet Node IRU600 is an example of an all-indoor microwave radio, which is one choice wireless operators should consider for implementations in North America.
There’s a lot of buzz in the microwave industry about the trend toward all-outdoor radios, but those who haven’t been through LTE deployments may be surprised to learn that based on our experience deploying LTE backhaul for some of the world’s largest LTE networks, all-indoor is actually the best radio architecture for LTE backhaul.
We can debate today’s LTE backhaul capacity requirements, but one thing we do know is that with new advances in LTE technology, the capacity needed is going to grow. This means that microwave radios installed for backhaul will likely have to be upgraded with more capacity over time. Although people are experimenting with compression techniques and very high QAM modulations and other capacity extension solutions, the most proven way to expand capacity is to add radio channels because it represents real usable bandwidth independent of packet sizes, traffic mix and the RF propagation environment.
All-indoor radios are more expensive initially in terms of capital expenditures, but they’re cheaper to expand and (as electronics are accessible without tower climb) are more easily serviced. While an outdoor radio connects to the antenna with Ethernet or coax cable, indoor radios usually need a more expensive waveguide to carry the RF signal from the radio to the antenna. So you pay more up front with an all-indoor radio but as the radio’s capacity grows you save money. There are several reasons.
When everything related to the radio is indoors, you just have a waveguide and an antenna up on the tower. To add radio channels with an all-indoor radio you go into the cabinet and add an RF unit. With an outdoor radio, you have to climb the tower, which can cost as much as $10,000. Also, when you add a new outdoor RF unit you may have to swap out the antenna for a larger one due to extra losses incurred by having to combine radio channels on tower….(read the full story at RCR Wireless).
Gary Croke
Senior Product Marketing Manager
Aviat Networks
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- September 7, 2012
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- July 27, 2012
Best Practices for Ultra Low Latency Microwave Networks
For discussion purposes of ultra low latency, two theoretical ultra low latency microwave networks are compared to an existing optical Chicago-NY network.
In today’s ultra-competitive High Frequency Trading markets, speed is everything, and recently wireless technologies, and specifically microwave networking, have been recognized as a faster alternative to optical transport for ultra-low latency financial applications.
Even though microwave technology has been in use in telecommunications networks around the world for more than 50 years, new developments have optimized microwave products to drive down the latency performance to the point that microwave can significantly outperform fiber over long routes, for example between Chicago and New York. This has provided a new market opportunity for innovative service providers to venture into the microwave low latency business.
Although reducing the latency of the equipment is an important consideration, the most important metric is the end-to-end latency. Many factors that influence overall end-to-end latency require a deep understanding of the technology and how this is applied in practice.
This white paper will show that to achieve the lowest end-to-end latency with the highest possible reliability and network stability not only requires a microwave platform that supports cutting edge low latency performance but also a combination of experience and expertise necessary to design, deploy, support and operate a microwave transmission network.
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- July 20, 2012
You can read more about how Aviat Networks is working with Basin Electric on its microwave backhaul network here: http://investors.aviatnetworks.com/releasedetail.cfm?ReleaseID=659669
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- April 4, 2012
Mobile World Congress 2012 Wrap Up
¡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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- March 1, 2012
A Timely Update on Wireless Security
Wireless Security Components
Traditionally, microwave networks have been unsecure—unsecure as far as any purpose-built payload encryption or secure management is concerned. Until recently, it was deemed essential only for the most confidential microwave communications of financial firms, defense agencies and government, where the law can require them. But now billions of people around the world rely on the Internet to deliver varies types of data traffic ranging from personal messages to financial transactions. This value and volume of traffic makes it an irresistible target for cyber criminals. As security measures are implemented in other parts of the network (core, access) it is fundamental to implement strong security measures in microwave networks.
Aviat Networks Strong Security suite for the Eclipse Packet Node microwave radio platform prevents the following attacks on the network:
Front door attack: Traditionally microwave networks have not encrypted their payloads. With many networks transitioning from TDM to IP not encrypting payload traffic is the equivalent “of leaving the front door unlocked.” Hackers, cyber criminals and even foreign governments could try to access the air link using methods such as the “man in the middle” to read unencrypted data streams. Aviat Networks’ solution is to implement Payload Encryption that protects all traffic over the air link including user data and Eclipse management data in the payload.
Backdoor attack: Unsecured NMS can be used to change the radio configuration, sabotage or divert traffic using network management. With Aviat Networks’ Secure Management all Eclipse Packet Node management and control commands are secured over unsecure networks.
Insider attack: Disgruntled employees or cyber criminals that have obtained inside access to the network can use this access to divert traffic or upload malware to the network. Aviat Networks implements complete AAA (Authentication, Authorization and Accounting) capability through a RADIUS server that can be used to prevent, or if happens, track and identify an inside security breach.
Covering all vulnerable areas of a microwave network, Aviat Networks’ Strong Security provides the toughest standards-compliant security protection in the market.
Eduardo Sanchez
Marketing Engineering Specialist
Aviat Networks
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- February 21, 2012
The kWh Joins the dB?
Some leading telecommunications carriers are quietly effecting a shift in design priorities. For microwave radio, for example, output power, receive threshold, system gain and various other performance parameters (the dBs) have always been important product differentiators. Equipment vendors have also strived to make their equipment ever smaller to fulfil a requirement to pack more capacity into less rack space. There is, however, what appears to be a shift in some quarters.
British Telecom (BT), Verizon and AT&T are among those passionate about reducing their energy consumption and, hence, their carbon emissions. Environmentally aware operators that have set themselves the challenge of reducing their overall energy usage are facing the challenge of doing so at a time when there is an exponential increase in demand for their services. The frequency with which the kWh is referred to by operators increases with each passing year.
BT was an early mover and has already reduced its UK carbon emissions by 60% since 1997 and reduced its energy consumption by 2.5% year-on-year, as reported Spring 2011. BT has set an incredibly ambitious target of cutting its carbon footprint by 80% between 1997 and 2020. How are they doing this at a time of growth? Well, BT has reported that their new 21st century data centers use 60-70% less energy and the resulting financial savings have made the centers profitable within 18 months. BT estimates that an incredible 50% of the energy consumed by a typical data centre can be consumed by cooling. By introducing fresh air cooling they have reduced this requirement by 85%, as much of the year no refrigeration is required.
Among other measures, BT has focused on energy efficiency of network equipment and also increased efficiency by supplying DC power directly to equipment rather than sustaining significant losses associated with converting AC power to DC. This is an incredibly inspiring record. BT is genuinely committed to its environmental policy believing that it has a responsibility to reduce power consumption, as one of the UK’s top ten energy users. There is certainly a compelling business case for their policy too as they have seen substantial savings and also a significant increase in the volume of business that requires environmental reporting. BT estimates that its UK business alone saved £35M or $54M for the year 2010/2011 over where their energy usage would have stood without the efficiencies introduced by their energy program.
Verizon has emerged as a key North American player and, witnessing what they considered to be apathy with regard to standardization, the Verizon NEBS group released an energy efficiency standard (VZ.TPR.9205) in 2008. NEBS had been traditionally focused on EMC (electromagnetic compatibility) and physical protection requirements such as survival over temperature and earthquake resistance. Energy efficiency became, therefore, an unexpected but vital third strand of NEBS for Verizon. Since then, energy efficiency and related topics have become key at the Verizon-hosted annual NEBS conferences. Verizon has launched a carbon intensity metric which measures Verizon’s carbon intensity by factoring the amount of CO2 produced per Terabyte of data. Year-on-year, Verizon achieved a 15.75% reduction 2009/2010. Verizon’s projections show a forecasted financial saving of around $22M for 2011. Equipment cooling is recognized by Verizon and AT&T as a big factor in energy consumption too but their method of managing this varies.
At this year’s NEBS conference both AT&T and Verizon made announcements that will affect the way that some vendors design their equipment. AT&T announced that from 1st January 2012 they will mandate equipment with airflow that flows front to back within the rack. This move is related to the fact that AT&T has established ‘hot aisles’ and ‘cool aisles’ within its centers. The aisle facing the front of the rack is the cool aisle and the equipment draws air from this aisle, exhausting it into the hot aisle. This allows for the hot air to be efficiently extracted from the center, resulting in significant reductions in the energy consumed by the HVAC system. Verizon also announced that it would be mandating front-to-back airflow in the future. They are seeking to include this as a requirement within GR-63-CORE as this Telcordia standard currently states front-to-back airflow as an objective only. Verizon’s motive for seeking this change to GR-63-CORE is the fact that they also have a hot aisle/cool aisle system. Verizon is also hoping to have the core NEBS standards updated to include energy efficiency requirements. If successful this will mean that NEBS certification, whether it is for equipment intended for Verizon or not, will need to meet a minimum efficiency specification and have front-to-back cooling. Another shift is that efficiency of equipment cooling is starting to be regarded ahead of equipment size by some operators. A slightly larger mechanical enclosure is easier to cool, using less energy. All of these shifts seem to suggest that environmental performance is taking its place alongside other parameters as a key consideration for some operators.
Aviat Networks’ Eclipse product line meets the Verizon energy efficiency standard and additional energy efficiencies are being built into future products. Aviat Networks is committed to working closely with customers, vendors and standards agencies to both understand and promote the requirement for environmental sustainability within the telecoms sector at a time when it is challenged with an explosion in demand.
BT’s sustainability report, 2011
More information on Verizon’s environmental sustainability
Footnote – NEBS (Network Equipment Building Systems).
Ruth French
Product Compliance Manager
Aviat Networks

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- December 6, 2011
What is Asymmetrical Link Operation?
Introduction
Last year one of our microwave competitors introduced a new development for the point-to-point licensed microwave market – asymmetrical link operation. There are some very real challenges with the growth of mobile multimedia that are driving interest in this approach. However there are numerous harsh realities involved in introducing such a ‘radical’ technique into the relatively conservative licensed microwave industry. The myriad of Regulatory studies and approvals that will be needed to enable asymmetric operation to be deployed in existing bands means that it could be years, if ever, before asymmetric links can be deployed in most countries around the world.
Today’s Licensed Microwave Bands are Exclusively Symmetric
In current licensed microwave bands and all commercially available equipment today, transmission is symmetric – i.e., the same capacity and bandwidth in both directions. Frequency bands are arranged for frequency division duplex (FDD) operation, where two identical channels are used for Tx (‘go’) and Rx (‘return’). Asymmetric operation is usually reserved for unlicensed time division duplex (TDD) radios, which use a single channel for both go and return.
Spectrum Borrowing
The proposed Asymmetrical scheme is based upon a concept called ‘Spectrum Borrowing’, where frequency spectrum is taken from the upstream direction of a lower capacity link, and given to the downstream direction of an adjacent higher capacity link.
Before - Symmetrical Microwave Network
A second (but related) proposal has been also tabled to amend the standard channel options from the current 7, 14, 28, 56 MHz to an n*7MHz arrangement (i.e. 7, 14, 21, 28, 35, 42, 49, 56 MHz), which is required to support the asymmetric concept.
Asymmetrical Microwave Network, after Spectrum Borrowing
What is driving the need for this Asymmetry?
The underlying rationale is that in 3G and 4G mobile networks, a majority of the traffic over the network is increasingly web- and video- based, meaning more capacity is needed in the backhaul network in the direction towards the base station, and less in the opposite direction back to the core.
However, while this is true today, new emerging mobile applications such as video chat, video uploading, P2P sharing, and new cloud based services (eg: iCloud), have the potential to change the imbalance between upload and download demand over the longer term. This presents a challenge for the proposed asymmetric implementation, which is fixed in nature, not dynamic. This means that the link has no way to adapt to instantaneous uplink/downlink traffic demand, or to change over time as more uplink capacity is needed. Changing this ratio could prove to be very difficult once an asymmetric link is in place and has been operating for several years.
Regulatory Approval
Making substantial changes in the way that licensed microwave bands are used is not a simple process, since strict regulations and standards at the international and national level have been put in place to ensure that links deployed in these bands are assured to be virtually interference free.
A proposal has now been submitted to the Electronic Communications Committee (ECC), the Regulatory Body responsible for amending the channel plans for the existing frequency bands, a part of the European Conference of Postal and Telecommunications Administrations (CEPT), representing 48 countries throughout Europe and Russia. The ECC has agreed to set up a study group to examine the proposal, which is due to report their finding in February 2013.
If the ECC agrees to amend the channel plans to permit asymmetric operation, which may not happen before 2015, the national regulator in each CEPT country will then have to decide whether or not to adopt the recommendations. Further lobbying will also be necessary beyond the CEPT region, for example with the FCC in the USA, to successfully influence regulatory policy in favor of Asymmetrical operation.
A Long Road to (Possible) Adoption
In summary, asymmetrical operation may be a potentially useful technique to improve the efficiency of backhaul networks and frequency utilization. However, introduction of this technique will be extremely difficult within existing congested frequency bands, and will face significant and lengthy regulatory scrutiny and approval before we will see widespread adoption.
Stuart Little
Director of Marketing

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- October 18, 2011