April 13, 2012
As we blogged last summer, the FCC has released 650 MHz of new wireless technology spectrum for Fixed Service wireless communication technology operators. Now Comsearch, a leading provider of spectrum management and wireless engineering services in the US, has highlighted this issue in its latest online newsletter, with an article that includes some very informative coverage maps showing the zones where the new bandwidth is available.
These maps are excellent at conveying the limitations of the newly released spectrum for microwave link applications in the 7 GHz (6.875–7.125) and 13 GHz (12.7–13.1) bands. After taking into account the zones that are reserved for existing Fixed and Mobile Broadcast Auxiliary Service (BAS) and the Cable TV Relay Service (CARS) users, these new bands are only available in about 50 percent of the US land mass covering only 10 percent of the population.
What do you think? Should the FCC loosen the spectrum sharing rules even more for 7GHz and 13GHz bands? Take our poll and tell us:
April 6, 2012
In 2011, the United States experienced its worst tornado outbreak in more than 50 years. And communication systems were not spared from the carnage.
In the video below, Robert Young, senior manager for Aviat Networks’ Americas TAC/NOC explains how the company’s San Antonio network operations center (NOC) and its expertise in disaster monitoring and recovery helped microwave communication systems rebound from severe weather challenges. He details how the Aviat Networks Technical Assistance Center (TAC) and NOC team provided support for customers during the 2011 tornado outbreak.
One of the special services Aviat Networks’ NOC offers is in the form of Special Event Recovery and Monitoring. Two of Aviat Networks’ major customers were directly affected by the 2011 tornado outbreak. The storms were tracked, and the customers were preemptively notified of the storm tracks. Approximately 600-plus tornadoes were monitored in one week, and Aviat Networks managed disaster recovery of more than 300 outages due to the storms.
March 15, 2012
To compare how different wireless backhaul network topologies perform under the same operating scenario, let’s analyze how a traditional hub-and-spoke and a ring configuration compare in connecting the same six sites (See table below). For the hub-and-spoke configuration, each cell site is provided 50 Mbps capacity in 1+1 protection. With five links and no path diversity, full protection is the only way to achieve five nines reliability. In this configuration, 10 antennas are employed, which average a large and costly 5.2 feet in diameter. Total cost of ownership for this six-site network is close to $700,000 for five years.
For a ring design for the same six sites, throughput of 200 Mbps is established to carry the traffic for each specific hop and any traffic coming in that direction from farther up the network. Designed to take advantage of higher-level redundancy schemes, the ring configuration only requires antennas that average 2.3 feet in diameter, which are much lower in cost compared to the antennas in the hub-and-spoke configuration. And even though the ring configuration requires 12 antennas and six links, its overall TCO amounts to a little under $500,000 over five years—30 percent less than TCO for the hub-and-spoke design for the same six sites.
This comparison is based upon deployments in the USA, where most operators lease tower space from other providers.
Senior Product Marketing Manager
December 21, 2011
Have you ever had an unusual experience at a microwave radio site?
Here’s one we would like to share with you. Aviat Networks Account Manager Mark Davis recently experienced an ascent of Mt. Pisgah in North Carolina (mid-Atlantic coast USA) in a cable car—climbing 3,600 feet in 11 minutes. The cable car is purpose-built to carry engineers to the TV broadcast tower on top of Mt. Pisgah, in this intance it transported 6-ft antennas and Aviat Networks radio gear. The microwave radio installation will connect U.S. National Park Service offices along the entire Blue Ridge Parkway.
Check out the video:
We are sure there are many more interesting examples of radio installations out there. Post comments below or email us your story or images. We want to hear from you!
September 22, 2011
Our partner, Symmetricom, recently announced the launching of a new segment of their SyncWorld ecosystem for microwave backhaul. Our hat’s off to them; this is great news for Symmetricom and the new players that are now on board. We boarded this train awhile back. After a couple years of collaborative testing between us, we first joined the ecosystem when it was initially launched in March at CTIA 2011.
So, what have we learned since then you might ask?
Well for one, packet based timing is still growing in interest, evaluation, and deployment. Customers around the world — including mobile operators, state and utility providers and others – are increasingly looking for timing solutions that operate over their Ethernet fiber and microwave network as effectively as their TDM timing solutions do. A recent Heavy Reading analyst report projects close to 2 million cell sites will have deployed the two most dominant solutions, IEEE 1588v2 and Synchronous Ethernet (SyncE), by 2015.
Secondly, we’ve learned this is by no means the technology race it started out to be. Remember when Blu-ray and HD–DVD were competing a few years ago? Or perhaps that has well faded into memory. Well, I still recall the industry buzz a couple years ago about whether Synchronous Ethernet (SyncE) was going to kill IEEE 1588v2, or vice-versa. Who was going to come out on top?
Telecom watchers and players are always primed for a tech battle it seems. Well lo and behold; this battle has become more of an alliance, as of late.
The dominant discussion today is now about how BOTH these technologies can co-exist, and where best to deploy them in a network, either side by side or in parallel, with one backing up the other. Hmmm, now that’s an interesting conclusion to a tech battle.
Case in point, a couple of our customers are planning to deploy both technologies to take advantage of their respective strengths and are in the process of doing just this. See this whitepaper for more information about synchronization over microwave backhaul or maybe this one for insight into deploying IEEE1588v2 synchronization.
So, with the reality today that packet timing is still growing and that options for packet timing (including TDM, 1588v2, SyncE, and GPS) will continue to co-exist for a long time, it becomes even more critical to seek experience when it comes to planning your sync migration.
An ecosystem is probably a good place to start, especially with those players that have been at it for some time.
Sr. Manager, Solutions Marketing
August 23, 2011
Rain fading (also referred to as rain attenuation) at the higher microwave frequencies (“millimeter wave” bands) has been under study for more than 60 years. Much is known about the qualitative aspects, but the problems faced by microwave transmission engineers—who must make quantitative estimates of the probability distribution of the rainfall attenuation for a given frequency band as a function of path length and geographic area—remains a most interesting challenge, albeit now greatly assisted by computer rain models.
A surprising piece of the puzzle is that the total annual rainfall in an area has almost no correlation to the rain attenuation for that area. A day with one inch of rainfall may have a path outage due to a short period of extremely high localized rain cell intensity, while another day of rain may experience little or no path attenuation because rain is spread over a long period of time, or the high intensity rain cell could miss the microwave hop completely.
Over the years, we have learned a lot about deploying millimeter wave microwave hops for our customers:
More information about assessing rain-induced attenuation is available in our white paper, Rain Fading in Microwave Networks.
August 5, 2011
Last year in August, Aviat Networks presented its argument for why fiber optics technology isn’t everything where backhaul of wireless networks is concerned. If anything, this point has only been reinforced by analyses and anecdotal stories showing that fiber can be overkill for the mobile backhaul requirements of LTE wireless. Plus, there is the simple truth that fiber cannot be deployed to every cell site due to financial and topological issues. That’s why microwave technology remains the world’s first choice for backhauling wireless networks. So let’s look at last year’s FierceWireless webinar slide presentation and refresh our memories.
Ovum found that demand for wireless backhaul equipment in North America will continue to grow as mobile operators upgrade their networks to support higher-speed LTE networking technologies. The most common backhaul strategy for mobile operators in the region comprises leasing services over fiber combined with owning and operating microwave-based facilities. Microwave has a distinct advantage vis-a-vis leased services over the long-term due to the opex associated with leasing.
If you would like to see more, you may register for the on-demand replay of the full webinar. It will also present the latest trends and advancements in microwave transmission technology that support the evolution of mobile backhaul networks to all-IP.
July 22, 2011
Microwaves are as old as the beginning of the universe. Well, they’ve been around for at least 13.7 billion years—very close to the total time since the Big Bang, some 14 billion years ago. However, we don’t want to go that far back in covering the history of microwave communications.
Having just observed the 155th anniversary of the birth of Nikola Tesla, arguably the most important inventor involved in radio and wireless communications, this is a good time to take a broader view of the wireless industry. If you have been in the wireless transmission field for some time, you are probably familiar with Dick Laine, Aviat Networks‘ principal engineer. He has taught a wireless transmission course for many years—for Aviat Networks and its predecessor companies.
The embedded presentation below comes from one of those courses. In a technological field filled with such well-educated scientists and engineers from some of the finest universities and colleges, it’s hard to believe that microwave solutions and radio itself started in so much controversy by men who were in many cases self-taught. Dick’s presentation goes over all of this in a bit more detail. Hopefully, it’s enough to whet your appetite to find out more. If you like the presentation, consider hearing it live or another lecture series on wireless transmission engineering at one of our open enrollment training courses.