Aviat Design, Aviat’s cloud-based link planning application, supports WTM 4800 E-Band and Multi-band designs. Aviat Design is the industry’s first and only integrated Multi-band link design solution showing a combined view of availability and capacity for the link. This enables easy, fast, intuitive E-Band and Multi-Band designs (all specs included, no pathloss files to download or update, easy cloud access). Popular design tools will require 2 separate link calculations for Multi-Band, and will not result in a combined design for the link, making it virtually impossible to understand the expected link performance or capacity or estimate the proper antenna size. Aviat Design is FREE for use at www.aviatcloud.com.
This large western US state had a longtime relationship with a microwave radio vendor and would have continued buying from them if their radios and support evolved with the State’s needs. However, over time its needs changed and it had to have more capabilities from its communications network. But it did not want to unnecessarily build new sites and erect costly new towers.
When designing microwave networks, backhaul engineers have a wide variety of techniques at their disposal. One method that remains highly effective is Space Diversity (SD). With SD, two antennas separated by some distance can increase the availability of a link from something less than 99.999 percent to in excess of five-nines uptime. However, the introduction of a second parabolic antenna on a microwave path poses a substantial increase in the capital expenditure (capex) budget.
Figure 1: 8-foot antenna (left) clearly much bulkier than a 3-foot antenna (right in carton). Basketball included to indicate relative scale.
You may have noticed we’ve been talking a lot lately about our new 39dBm EHP radio (the most powerful digital microwave radio ever built by the way). We’ve been getting a phenomenal response to this product mostly because of the real business benefits it delivers…benefits largely related to the antenna.
As a rule of thumb in microwave backhaul, the more powerful the radio (i.e., system gain) the smaller the antenna has to be (i.e., overall diameter). More than any other factor, smaller antennas drastically lower the total cost of ownership for microwave.
LTE mobile connectivity now exists in many more urban places than not. Virtually all big cities have multiple choices for LTE and most have at least one choice for LTE Advanced—the real 4G wireless. For example, you can see iPhone and Android users taking advantage of all this high-capacity coverage as they leisurely view high-definition YouTube videos without buffering and actually livestream major league sports in cafes, parks and just walking around at lunch.
- September 18, 2012
- Antenna diversity, Antennas, China Basin, Dick Laine, horn antenna, microwave, microwave propagation, Principal Engineer, Radio Head Technology Series, Radio Heads, Radiohead, San Francisco, Space Diversity
Horn antennas on the roof of a microwave relay station near Madison St. and 17th Ave, Capitol Hill, Seattle, Washington State, USA. (Photo credit: Vladimir Menkov via Wikipedia)
Between any two microwave radio antennas, there is one direct ray and multiple refractive/ reflective multi-path rays. In the eighth and last installment of our Radio Head Technology Series, Aviat Networks Principal Engineer and master storyteller, Dick Laine, relates how restrictive tower rules for San Francisco’s historic China Basin Building required fine adjustments of a horn antenna to resolve reflective rays from the surrounding bay.
As Dick tells it, to accommodate a Space Diversity arrangement, one horn antenna on the building had to be hung upside down. During the installation process, the alignment for the upside-down diversity antenna created a reflection point 3 miles out into the bay. Because of this installation, the performance was horrible, but at the time no one knew why. For example, when a little speedboat or anything larger went through the reflection point, there would be an outage as the signal was interrupted. There did not seem to be an obvious fix to the alignment issue. The horn antenna did not have a way to check the alignment on the horizontal with a bubble level.
To find out how Dick solved this antenna mystery, register for the Radio Head series (it’s free). Then to put it all in context, Dick goes over Huygens’ Principle as it applies to microwave signal diffraction. And if you ever wondered what happened to periscope antennas, Dick provides some key insight! Tune in to find out!
- The Truth About Terahertz (spectrum.ieee.org)
- GL Conveys the Availability of RF Design Tools (virtual-strategy.com)
- FCC Rule Changes Lower the Cost of Microwave Deployments (aviatnetworks.com)
- Why Bigger is not Always Better for Mobile Backhaul! (aviatnetworks.com)
- Got Protection? Diversity Schemes and Other Methods (aviatnetworks.com)
- Cole Valley Cell Tower Authorization Approved By Planning Commission (tantek.com)
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).
Senior Product Marketing Manager
- Microwave Backhaul for Public Safety LTE (aviatnetworks.com)
- Sprint: Ethernet backhaul gives us 20 times more bandwidth (fiercebroadbandwireless.com)
- Microwave Wireless Backhaul Case Study: Tooele County (Utah) (aviatnetworks.com)
- Construction, Not Capacity, is the Real LTE Challenge in U.S. (aviatnetworks.com)
- Worldwide Survey Finds Mobile Operators Aren’t fully Benefitting from the Value of IP/Ethernet Backhaul Architectures (infovista.com)