July 7, 2017
How to Avoid Costly Emergency Repairs by Performing Proactive Maintenance in 4 Simple Steps
By Ramon Morales, NOC Operations Team, US
It’s 2:30 AM Saturday morning and the phone rings dragging you out of a deep sleep. Groggily you answer the phone and a voice at the end of the line is alerting you that the communication system is in alarm and traffic is down. While trying to figure out what’s going on, you remember you are the person responsible for your company’s communication infrastructure.
June 7, 2017
Microwave radio choices
There’s no one-size-fits-all in microwave. Each radio architecture comes with tradeoffs, so you need to weigh the choices in each segment of the network to get the right product mix for your business. To determine your best solution, first establish your requirements from a capacity, reliability, operational, and cost perspective. Then choose the right product. Microwave’s major technologies include the following.
May 25, 2017
5 Things You Should Know About RSL
By Ramon Morales, NOC Operations Team, US
Do you remember the last time your blood pressure was checked? I remember staring at the results wondering what the numbers meant. Usually my thoughts are, “Great, does this mean I’m healthy or should I be concerned?”
Recently, one of our customers had a similar experience with an email received from our customer service group. The customer’s initial impression was that the content received was vague and meaningless. “What am I supposed to do with this information?”, the customer asked.
October 18, 2013
Lessons Learned: Transitioning from TDM to IP
Cell phone tower near Lozen, Bulgaria. Photo credit: Plamen Agov • studiolemontree.com [CC-BY-SA-3.0 or GFDL], via Wikimedia Commons
Aviat Networks has been there all along the way, helping operators design and deploy aggregation systems. We’ve seen and learned a lot as some of the leading mobile phone carriers have upgraded their networks. Now as LTE works its way into mainstream status, cell phone networks are transitioning to full-IP, the underlying technology of LTE.
June 12, 2012
Record 180 km Hybrid Diversity IP Microwave Link
Survey view from Belize toward Honduras, at 1000 m AMSL
Link between Honduras and Belize Crosses Water and Land
Last year I wrote about the world’s longest all-IP microwave link, stretching 193 km over the Atlantic Ocean in Honduras. Aviat Networks and Telecomunicaciones y Sistemas S.A. (TELSSA) designed and implemented this link together. This year, Aviat Networks and TELSSA again worked together to build another link and achieve another record—an Eclipse microwave link between Honduras and Belize that crosses 75 km of the Atlantic Ocean and 105 km of rugged terrain for a total path length of 180 km. This is a new world record for a hybrid diversity microwave link!
After the success of implementing the 193km link over water, Aviat Networks and TELSSA were eager to meet the challenge to connect Honduras and the neighboring nation of Belize using a single microwave link. Aviat Networks network engineers and TELSSA engineers were able to use their extensive knowledge of local propagation conditions, thorough understanding of long path design principles and precise installation practices to successfully implement this 180km microwave link.
Long Path Design Considerations
As outlined in the article last year for the longest all-IP hop, a deep understanding of path design considerations and experience in microwave transmission path design are necessary to successfully complete a long path design. Key considerations involved:
- The effect of antenna diameter on highly refractive paths
- Precise alignment of the antennas to mitigate the effect of refractivity
- Optimum RF and space diversity spacing to counter elevated divergent dielectric layers
- Deterministic prediction of the variations of atmospheric conditions
- Multi-path propagation delay
To read more about this world-record Hybrid Diversity IP microwave link, download the full article.
Ivan Zambrano
Senior Network Engineer
Aviat Networks
Related articles
- The Worlds Longest All-IP Microwave Link (aviatnetworks.com)
- 3 Truths about High Fade Margin in Point-to-Point Path Design (aviatnetworks.com)
- Dick Laine’s 4 Keys to Successful Transmission Engineering of Microwave Links (aviatnetworks.com)
- 10 Things to Know About the Status of Asymmetrical Wireless Backhaul (aviatnetworks.com)
- 3 Models for Microwave Link Error Performance? Laine Explains (aviatnetworks.com)
May 11, 2012
3 Models for Microwave Link Error Performance? Laine Explains
In the second episode of Aviat Networks’ Radio Head Technology Series, Principal Engineer Dick Laine explains ITU-R models for Fixed Wireless Systems.
As most radio engineers know, Vigants calculations, which are discussed in a broadly cited Bell System Technical Journal article, are widely used to determine reliability or error performance for microwave link design. In Video 2 of Aviat Networks’ popular Radio Head Technology Series, which is now available for viewing, Principal Engineer Dick Laine explains how he uses Vigants calculations in conjunction with the three completely separate ITU-R Fixed Wireless System (FWS) models for TDM.
Because of all these models, he likes to use Vigants calculations as a “sanity check” to see that he is close to the correct result for his path engineering plans. The free Aviat Networks’ Starlink wireless path engineering tool can be used to handle Vigants calculations for Aviat Networks’ and other vendors’ equipment.
Can’t wait to hear more of Dick’s experienced views on microwave radio transmission engineering? You can get ahead of the learning curve by registering for the series and get these videos sent to your inbox as soon as they are released.
Related articles
- ITU calls for inclusion of ICT at Rio+20 Summit (ghanabusinessnews.com)
- Metropolitan Area Network (computrnetworking.wordpress.com)
- 3 Truths about High Fade Margin in Point-to-Point Path Design (blog.aviatnetworks.com)
- LTE – Lessons Learned So Far (blog.aviatnetworks.com)
- Dick Laine’s 4 Keys to Successful Transmission Engineering of Microwave Links (blog.aviatnetworks.com)
April 13, 2012
Coverage Maps for New Wireless Spectrum Available to Fixed Services
United States radio spectrum frequency allocations chart. The FCC has freed 650 MHz of spectrum to increase sharing possibilities for 7GHz and 13GHz bands. (Photo credit: United States Department of Commerce employee via Wikipedia)
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:
Related articles
- Senators Task FCC to Find Alternate Spectrum for LightSquared (phonescoop.com)
- Are Auctions an Appropriate Way to Allocate Microwave Spectrum? (aviatnetworks.com)
- Feds Update Spectrum Release to Relieve Wireless Congestion (aviatnetworks.com)
- Singapore IDA contemplates reserving spectrum for new entrant as it consults on 4G auctions (robbratby.com)
March 15, 2012
Diverse Wireless Network Topologies Cost Savings
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.
Gary Croke
Senior Product Marketing Manager
Aviat Networks
Related articles
- Network Topologies (computrnetworking.wordpress.com)
- Microwave Total Cost of Ownership (TCO) Pt. 1 (blog.aviatnetworks.com)
- Microwave Total Cost of Ownership (TCO) Pt. 2 (blog.aviatnetworks.com)
- Tower Technology Summit: Microwave Backhaul Gaining Momentum (files.wordpress.com)
- Strategies for Lowering Your LTE/4G Backhaul Bill – WCAI Webinar (wcai.com)
August 23, 2011
4 Realities about Rain Fading in Microwave Networks
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:
- Rain outage approximately doubles in each higher millimeter wave band, e.g. 18 to 23 GHz
- Rain outage is directly proportional to path length—assuming a constant fade margin for each hop
- Rain outage in tandem-connected short hops is the same as for a single long hop—if they have the same fade margin
- Multipath fading in optimally aligned millimeter wave hops does not occur during periods of heavy rainfall, so the entire path fade margin is available to combat rain attenuation fades
More information about assessing rain-induced attenuation is available in our white paper, Rain Fading in Microwave Networks.
Related articles
- The influence of rain attenuation (sce.carleton.ca)
- The World’s Longest All-IP Microwave Link (aviatnetworks.com)
- Comparison of Multiple Rain Attenuation Models with Three Years of Ka Band Propagation Data Concurrently Taken at Eight Different Locations (spacejournal.ohio.edu)
- Microwave Wireless Backhaul Case Study: Tooele County (Utah) (aviatnetworks.com)
- Proposed Rain Attenuation Model Revised From ITU Used For Prediction in Tropical Climates (aprsaf.org)
August 5, 2011
Fiber Isn’t Everything: Key Role of Microwave in Mobile Backhaul
If fiber is this much of a mess in your wiring closet, just imagine the difficulty of deploying it to your cell site. Image by DrBacchus (Rich Bowen) via Flickr
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.
These slides present the findings of an Ovum survey of North America’s largest backhaul players to understand their strategies regarding media types used to supply cell-site backhaul.
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.
Related articles
- Telecom PR: Looking for the “Back Story” in Today’s Wireless Boom (customerthink.com)
- Backhaul for the Mobile Broadband or Wireless Broadband Network (aviatnetworks.com)
- Pictures From LTE World Summit (for 4G Wireless) (aviatnetworks.com)
- Ethernet OAM Meets Demands on Microwave (Wireless) Networks (aviatnetworks.com)
- Small Cell Mobile Backhaul: The LTE Capacity Shortfall (aviatnetworks.com)
July 22, 2011
Evolution of Microwave: History of Wireless Communications
This image of microwave energy in a "total sky" picture of the known universe shows it's everywhere in primordial space, more than 13 billion years ago.
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.
Related articles
- NASA’s ‘Age of Aquarius’ Dawns With California Launch (spacefellowship.com)
- Solar Power from the Moon (empressoftheglobaluniverse.wordpress.com)
- Ireland Issues Spectrum Consultation on Wireless Communications (aviatnetworks.com)
- Backhaul for the Mobile Broadband or Wireless Broadband Network (aviatnetworks.com)
- Homage to Nikola Tesla, Great Inventor of Wireless Technology (aviatnetworks.com)