Ciena And Aviat Team Up On Unified Fiber-Microwave Solution For Utilities
  • October 18, 2017

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.

  • October 2, 2012

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

  • September 7, 2012

All-Indoor Microwave: LTE’s Best Backhaul Solution for North American Operators

Eclipse Packet Node IRU600 all-indoor microwave radio

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

  • July 20, 2012

Best Practices for Ultra Low Latency Microwave Networks

Theoretical Chicago-NY microwave networks using existing towers compared to existing optical network

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.

  • February 21, 2012

A Timely Update on Wireless Security

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

  • December 6, 2011

The kWh Joins the dB?

kWh imageSome 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

  • October 18, 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.

What is Asymmetrical Link Operation?

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.

What is Asymmetrical Link Operation?

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

  • July 1, 2011

Antennas: Why Size is Important for This Wireless Equipment

Antenna tower supporting several antennas. The...

Image via Wikipedia

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

Related articles
  • Testing the T-shirt antenna (physorg.com)
  • Ball Aerospace to build F-35 antennas (bcbr.com)
  • Small Cell Mobile Backhaul: The LTE Capacity Shortfall (aviatnetworks.com)
  • Ireland Issues Spectrum Consultation on Wireless Communications (aviatnetworks.com)
  • Network Services from Aviat Networks’ Network Operations Center (aviatnetworks.com)
  • June 24, 2011

Mobile Security Requires More Than Secure Wireless Devices

Person with PDA handheld device.

Image via Wikipedia

When people think of mobile security, they usually think of encryption for their smartphones, tablet computers such as the BlackBerry PlayBook or other wireless devices. Or they think of a remote “wipe” capability that can render any lost device blank of any data if some unauthorized party did in fact try to enter the device illegally. These wireless solutions are all state-of-the-art thinking in the mobile security community. And many wireless equipment OEMs and third-party mobile security providers offer them.

But they only protect the data on the devices. They only protect so-called “data at rest” once it’s been downloaded onto the iPhone or iPad. They don’t speak to the need to cover “data in motion” as it is transmitted over the air. Some parts of the over the air journey are protected by infrastructure in the form of Wi-Fi and GSM. One is notoriously subject to human failing to enable security and the other has been broken for sometime. And then there is wireless security for backhaul. In this area, there has not even been an industry standard or de facto standard established. And most microwave solutions providers don’t even offer options for wireless security on the backhaul.

Fortunately, this is not the case across the board. Strong Security on the Eclipse Packet Node microwave radio platform offers three-way protection for mobile backhaul security: secure management, payload encryption and integrated RADIUS capability. Read the embedded overview document in full-screen mode for more details:

  • April 20, 2011

Unlocking Capacity Block Through Higher Order Digital Modulation

If you are reading this post, then you probably have heard about “4G”, the 4th generation cellular network. For a cell phone user, 4G means improved data speeds that allow faster delivery of multimedia-based applications, see our previous post, What is 4G?, for more details. On the other hand, the network operator desires to spend a minimum on upgrading network infrastructure and prefers to buy a backhaul solution that supports current and near future capacity demands of a cellular network.

Thus, it is important to improve the capacity of wireless backhaul links. To increase transmission capacity, wider channel spacing can be used. However the wireless spectrum is expensive and may not be available in some countries. Using transmission in high frequency bands, such as 60 GHz and above, provides the bandwidth needed to increase capacity. However, very high radio frequencies increase the cost of radio components. In addition, 60 GHz links limit transmission range due to high absorption of radio waves by the atmosphere, making this solution somewhat cost inefficient. One efficient way of improving the capacity of a communication link is to increase the order of the digital communication modulation scheme used for transmission.

In simple terms, digital modulation is the process of mapping a group of data bits into an information symbol that gets transmitted, after up-conversion to the radio frequency (RF) of the link. The most popular digital modulation scheme used in wireless radios is known as quadrature amplitude modulation (QAM). For a given symbol rate, increasing the modulation order, or equivalently packing more bits per symbol, would be an effective way to increase the capacity of a microwave link. For example, each symbol in a 64-QAM signal represents 6 data bits, while for 256-QAM and 1024-QAM signals it represents 8 and 10 data bits, respectively. Therefore, 1024-QAM provides (theoretically) a 25 percent increase in capacity over 256-QAM and an impressive 67 percent increase in capacity compared to 64-QAM.

The price paid for achieving such an increase in capacity is more complex signal processing algorithms and stricter requirements for channel quality, e.g. higher signal-to-noise ratio (SNR) at the receiver is required. In that case, increasing the modulation order for some networks under normal operating conditions can have a diminishing return on throughput. This is due to the fact that the required SNR for an acceptable receiver performance rarely can be met.

Why this is the case? Let us briefly discuss the challenges in increasing the modulation order. Higher modulation order results in larger pool of symbols available for transmission. For example, for 64-QAM, there exists 64 symbols in a 2D grid (known as constellation points) compared to 1,024 symbols for 1024-QAM for the same grid size. Clearly, increasing the number of symbols (assuming fixed power) makes the symbols closer to each other in this 2D grid. Thus, data detection at the receiver becomes more susceptible to errors due to impairment.

In practical terms, receiver circuits are affected by thermal noise, clipping and non-linearity of power amplifiers, phase noise and many other distortions that are beyond the scope of this post. It is worth mentioning that increasing the signal power beyond some limits results in actually decreasing the received SNR since many of these distortions associated with RF circuits are dependent on the transmitted power. Rather, the way to increase the modulation order is to improve the detection schemes and build circuits that are less susceptible to power-related distortions, along with improving the correction mechanisms at the receiver for phase noise and other impairments.

At Aviat Networks, we have the expertise and knowledge to build the highest quality microwave radios that can work at cutting edge signaling schemes. We will make sure that our customers see a sizable return—not a diminishing one from increasing the modulation order. Our pledge is that microwave backhaul will always exceed the capacity requirements of our customers.

Ramy Abdallah,

Senior Signal Processing Engineer, Aviat Networks

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