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.

Diversity, Hot Standby and Alarms for Wireless Backhaul—Oh My!

Microwave radio relay tower on Cimetta mountai...

(Photo credit: LittleJoe via Wikipedia)

Do not be Alarmed by this latest video in the Radio Head Technology Series (complimentary registration). For the insider’s perspective on Hot Standby, we will not keep you waiting. Dick Laine, Aviat Networks’ principal engineer, has many informed views on Diversity and relates them in his familiar relaxed presentation style.

All puns aside, Dick covers the multitude of options available in Diversity Schemes (and all their acronyms!). Plus, there is a lot to know about the differences in asymmetrical splitters for digital radios and their analog predecessors. Turns out there is no point in using symmetrical splitters in digital microwave radios. Even a heavily asymmetrical split provides as much protection as a symmetrical split but it avoids 2-3 dB in fade margin losses, providing significantly more uptime.

And if there is anything you need to know about Alarms, Dick takes a fine-toothed comb to the subject and teases out the details, providing context for the strategy of how they function in keeping your wireless communication network online. Dick will also tell you how improvement in digital radios has led to large gains in recovery time when radios in a Hot Standby arrangement are switched and quadrature relock can now essentially be avoided. On errorless switching, although it has greatly benefitted microwave radio usage, Dick will tell you the importance of early warning alarms to it.

So make no mistake, Dick is your information source for all things microwave radio—wrap your head around it!

Microwave Backhaul for Public Safety LTE

US Navy 031026-M-4815H-029 Fire fighters from ...

(Photo credit: Chance W. Haworth via Wikipedia)

Public safety agencies will soon experience a dramatic improvement in communications capabilities enabled by advances in technology. New broadband multimedia applications will give first responders and commanders alike far better situational awareness, thereby improving both the effectiveness and safety of all personnel charged with protecting the public.

The specific technology, now mandated by the U.S. Federal Communications Commission (FCC) for all new emergency communications networks, is Long Term Evolution, or LTE—a fourth-generation (4G) broadband solution. The FCC has also allocated licensed spectrum to ensure the best possible performance in these new networks. These FCC rulings support the goal of achieving an interoperable nationwide network for public safety agencies.

The FCC chose LTE based on its proven ability to support voice, video and data communications at remarkably high data rates that were previously only possible with wired links. Although there will be some differences in a nationwide public safety network involving capacity and coexistence with Land-Mobile Radio communications, lessons learned from LTE’s deployment in large-scale commercial mobile operator networks will help ensure agencies are able to achieve the FCC’s goal cost-effectively. Continue reading

4G Upgrade Path Drives Backhaul Migration in Kenya

Safaricom's Internet Broadband Dongle (with SI...

Burgeoning WiMAX and 3G data traffic from subscriber devices such as Safaricom’s Internet Broadband Dongle (with SIM Card) are driving the mobile operator to migrate from TDM to hybrid microwave backhaul. (Photo credit: whiteafrican via Flickr)

Migrating legacy mobile backhaul networks that were designed for TDM traffic to add support for high-speed Ethernet data for 3G and 4G mobile technologies is one of the biggest challenges for operators worldwide. Each case is unique and poses its own quirks and potential pitfalls. Mobile operators must juggle new technologies, cost pressures and the need to maintain existing services or risk driving customers to the competition.

For Safaricom, the leading mobile operator in Kenya and one of largest in all Africa, the case involved preserving its E1 capacity for voice calls and simultaneously adding Ethernet/IP bandwidth for burgeoning 3G and WiMAX data traffic. As many mobile operators have done in the past, Safaricom built its network over time. Many parts of the network are still legacy 2G TDM technology. However, things are changing rapidly, with 3G subscriber numbers up 85 percent in 2011 year over year.

Many of these subscribers are consuming ever-increasing amounts of data bandwidth. Safaricom’s TDM based backhaul, making use of Ethernet-to-E1 converters, is finding it hard to keep up with demand. To help resolve the situation, the operator called on Aviat Networks, one of its incumbent solution providers. Using its market leading hybrid radio solution, the modular Eclipse microwave networking platform, Aviat Networks enabled Safaricom to add IP data capacity as necessary while keeping E1 capacity for voice calls.

In addition, the stage has been set for Safaricom to make the eventual migration to all-IP backhaul. With the modular Eclipse platform, it can transition on its own schedule. For more information, read the complete Safaricom case study in the frame below or download the PDF:

How is Buying a Wireless Network like Buying a Boat?

Downeast style charter boat Wreck Valley

Buying a network is like buying a boat in that you do not really know what you need/want until after you have bought it. (Photo credit: Wreckvalle via Wikipedia)

Think about this phrase carefully: “Buy your second boat first.” Lately, I have been thinking of that phrase, which I once read in a boating magazine, and how it parallels some of the thinking processes wireless operators go through when making their technology and product decisions.

Often, when it comes to boating, you do not know what kind of “boat” you want or that you are even in the market. You show up to the boat show and are overwhelmed by the number of models, features, prices, etc.

To make a long story short, you end up picking something that is shiny/new, fits your near-term budget and matches how you envision the experience. What you did not know is how the “boat” rides in the water, how well it will perform with your children trailing in the water in an inner tube, how it is at storing all your swag, how roomy it really is once you add your friend’s family and the dog, etc. It is only after you get to know these things and “boating” in general that you start to realize what it is that you really want.

But now, you are stuck for at least a few years since—as you can imagine—you cannot easily trade in a “boat” that you have owned for just a short period of time. You need to stick it out until it makes sense financially, all the while watching “boats” you really want zipping around on the lake. If only you could go back in time and buy your second boat first. This experience draws parallels to wireless network buying decisions for a few reasons:

  1. Depreciation of wireless networking assets—much like a boat, the network does not pay for itself for a number of years down the road. Memories and the fun on the boat is really the only way to assign the boat a monetary value, but a wireless network is similar in that its usage is paying down on the investment
  2. What’s shiny/new is not always what you actually need—don’t be emotional. You need to understand what it is you really want to build toward. Stop thinking about how you can get by on the cheap to satisfy a relatively short-term, emotional goal
  3. Experience/expertise—whether buying a boat or buying a wireless network, find someone you can trust, someone who has done it before and has the experience to work with you on the complete package, the solution and total cost of ownership. Test-drive your friend’s boat for a day or take him to the boat show

Suffice to say you really cannot predict the future, but you should know where you want to go and where you want to be. Knowing you should be thinking about how to build the right network first just makes sense.

Steven Loebrich
Director, Partner and Solutions Marketing
Aviat Networks

Protection and Diversity: 100 Percent Uptime the Goal

English: BT Thornhill microwave radio tower

The BT Thornhill microwave radio tower above demonstrates a Space Diversity protection scheme with its parabolic antennas placed apart from one another (Photo credit: Peter Facey via Wikipedia)

Traffic disconnect is unacceptable for most microwave systems, especially for homeland security and utilities. But Aviat Networks Principal Engineer Dick Laine says that it is economically unviable to have a microwave radio system that provides absolutely 100 percent uptime to accommodate every possible traffic downtime scenario. He adds that towers, waveguides and all other hardware and infrastructure would have to be completely bulletproof. This is true of every telecommunication system.

However, with protection schemes and diversity arrangements in today’s wireless communication solutions, microwave transmission can get very close to mitigating against long-term traffic outages (i.e., > 10 CSES, consecutive severely errored seconds) and short-term traffic outages (i.e., < 10 CSES).

In pursuit of the 100 percent uptime goal, Dick goes over many of the strategies available in the newest video in the Radio Head Technology Series, for which there is complimentary registration. For example, there are many approaches to protection, including Hot Standby and Space Diversity. In particular, Dick points out Frequency Diversity has advantages over many protection schemes, but few outside the federal government are able to obtain the necessary waivers in order to use it. Hybrid Diversity uses both Space Diversity and Frequency Diversity to create a very strong protection solution. A case study outlining Hybrid Diversity is available.

Other concepts Dick covers in this fifth edition of Radio Heads includes error performance objectives, bit error rate, data throughput, errorless switching, equipment degradation, antenna misalignment, self-healing ring architecture and something called the “Chicken Little” alarm.