Getting Schooled: 5 Reasons to use Class 4 Antennas

Class 4 antennas helped reduce interference due to congestion for 3 sites in South America

As mobile phone and other wireless networks “densify” in the parlance of the day, airwave congestion will inevitably rise causing greater interference. Generally, microwave path planners will use dish antennas that provide tighter radiation patterns with more focused main beams and smaller side lobes to overcome interference that results from congestion.

To indicate the tightness of their radiation patterns ETSI (European Telecommunications Standards Institute) classifies antennas from 1 to 4 with higher classifications having tighter radiation patterns. Until recently, to fight interference in most circumstances wireless transmission engineers would resort to Class 3 antennas for deployment scenarios where “very high interference potential” existed.

However, the situation has changed. More drastic implementation scenarios now drive path planners to invoke more dramatic solutions. That includes use of Class 4 antennas, which are for “extremely high interference potential” situations, according to ETSI. For a more detailed treatment of antenna classifications and radiation patterns, see the ETSI document “Fixed Radio Systems; Point to Point Antennas.”

It’s an urban thing
In most cases, microwave radio congestion that leads to interference problems occurs primarily in urban locations. With wireless backhaul sites in much closer proximity in urban areas than in rural or suburban locales, there it’s more likely that side lobes from microwave transmitters could become sources of secondary RF radiation, which can overlap with point-to-point links between neighboring sites.

For example, according to an Aviat Networks analysis of three wireless sites in South America that recently experienced interference issues, at one site the congestion was so intense as to make one complete channel unusable. Even if Class 3 antennas were used, the interference levels were too high to be able to reactivate the disabled microwave channel.

Wider channels, larger capacity
For situations where the operator needs to increase capacity from a wireless backhaul site, the easiest way remains widening the channel size. But at sites that experience extremely high interference, the operator may not be able to coordinate radio frequency pairs in wide channels with Class 3 antennas. However, moving up to Class 4 antennas would allow the operator to optimize the signal-to-noise ratio and let higher modulations come into play, so wide channels could be coordinated with correspondingly higher data rates.

Smaller is more
In cases of high interference, larger antennas can be used to reduce it. For a subset, smaller Class 4 antennas can be used instead of their oversize Class 3 counterparts. Thus, operators who deploy Class 4 antennas gain the added benefit of dropping down a parabolic dish antenna size as compared to a Class 3 antenna in the same application. In general, smaller dishes advantage the operator due to their lighter weight and lower opex tower charges, albeit with an initially bigger upfront capex. Because Class 4 antennas represent an elevated level of precision tooling and more detailed manufacturing versus lower class antennas, capex of these passive, higher-performance infrastructure pieces always weighs in the balance.

Other considerations
As we’ve seen, Class 4 microwave antennas have many general uses. They also are very good alternative solutions for specific industries. For example, utilities often find it difficult to implement Adaptive Coding and Modulation schemes in their backhauls, so Class 4 antennas can provide another way for them to achieve their connectivity and capacity goals.

Lower frequency bands (i.e., less than 11 GHz) have long had access to Class 4 antennas. More recently, antenna manufacturers such as Commscope have begun to make Class 4 antennas for higher frequency bands (e.g., 13, 15, 18, 23 GHz). And RFS has also expressed interest in supplying higher frequency class 4 antennas.

This overview has provided a broad grounding in Class 4 microwave antenna subject matter, but for more in-depth information please download the Aviat white paper “Use of Class 4 Antennas” for which no signup is necessary.

3 Ways to Get Smart About Nodal Microwave

At a time in the not-so-distant past, there was only one way to implement microwave radio: one radio link per microwave terminal. Did not matter what type of link it concerned: protected, non-protected or multi-channel. From the advent of digital microwave radio in the 1980s and 1990s, terminals typically had no options for integration of co-located telecom devices. And to interconnect muxes or switches required external cabling and possibly a patch-panel.

Then in the early 2000s, so-called “nodal” radios came into vogue. Designed to address the drawbacks of the one-radio-one-link paradigm, a single microwave radio node could serve as a platform for multiple links. There were still limitations when it came to radio and switch interactions, but multiple sources of traffic could now be integrated and connected on the nodal platform. Continue reading

Aviat Networks wins best Microwave Backhaul Provider award in Ghana

At the Ghana Telecom Awards in May 2015. Ahmed Adama, Aviat Ghana country manager (right) proudly accepts on behalf of all Aviat Networks the honor for Best Microwave Backhaul Vendor of 2015.

At the Ghana Telecom Awards in May 2015, Ahmed Adama, Aviat Ghana country manager (right) proudly accepts on behalf of all Aviat Networks the honor for Best Microwave Backhaul Vendor of 2015.

At the recently concluded Ghana Telecom Awards held in May 2015, Aviat Networks won the Microwave Backhaul Vendor award for the second year in a row. Based on a survey of telecom industry participants, Aviat bested all the other major microwave specialists and one of the top three telecom generalists.

“I am very proud to inform you that Aviat Networks has been honored again as the best overall microwave backhaul solutions provider in Ghana,” said Ahmed Adama, country manager, Ghana, Aviat Networks. “The combination of our microwave networking technology and full turnkey service capability was key to securing this award.” Continue reading