What is a Class 4 Microwave Antenna?
Class 4 Antennas explained:
Class 4 antennas provide the current best RF performance allowing mobile operators and Wireless Internet Service Providers (WISP) to increase the link capacity of a network by deploying new microwave links where high levels of interference are present. Class 4 antennas will allow customers to offer the highest performance in even the most congested environments. The higher side lobe suppression supports networks in ultra-dense areas and enables earlier reuse of frequencies. The lower interference increases the carrier-to-interference-ratio and allows smaller antennas with better link throughput, reducing tower leasing fees. The lower interference also enables higher modulation schemes, increasing the data capacity per antenna.
Benefits of a Class 4 Antenna
Increase the link capacity of the network
– Improved radiation patterns for ETSI Class 4 providing better performance
– Less interference and higher carrier-to-interference ratio
– Allows radios to operate at higher modulation levels
• Minimize the total cost of ownership
– Improved network efficiency
– Facilitates better re-use of a frequency channel
– Small antennas with better link throughput reduces tower leasing fees
Intended Use for Class 4 Antennas
Class 4 antennas are intended 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.”
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 Better
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.
According to Andy Sutton, Principal Network Architect at EE:
Using Comsearch’s iQ.linkXG microwave planning software, CommScope analyzed the technical and commercial benefits of using Class 4 Sentinel antennas in the network. The results were most impressive. For the two frequency bands of the microwave backhaul network studied, which is comprised of over 6,200 links in total, the core findings were:
- Potential savings of $5 million in total cost of ownership (TCO) over five years by enabling a greater link density and therefore reducing the need for third party Ethernet Leased Lines
- Greater utilization of owned block allocated spectrum reduced the need for link by link licensing (from the national regulator) and therefore could save $44,000 in license fees over five years
- $4.5 million could be saved per year based on optimizing capacity by freeing congested channels while still ensuring new links met the strict quality of service criteria
- 96 percent and 31 percent of links which couldn’t be planned due to frequency congestion in 40 and 10 GHz could be assigned a channel, respectively
- A strong opportunity to trade some of the above by reducing antenna size and thus reducing TCO on tower lease costs
(content from EE above reproduced with acknowledgement from Commscope. Other content including photos from RFS).
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