April 22, 2021
With the current landscape of network economics and challenges associated with capacity and spectrum, having multiple tools for link deployments, capacity growth, and future-proofing are necessary. In this blog, we’ll discuss the concept of Microwave Multi-Band, or the use of two different microwave frequency bands over one link, and specifically the combination of 6 GHz and 11 GHz.
In previous blog posts, we have talked a lot about Multi-Band in the context of combining a wide channel in the 80 GHz E-Band with a narrower channel in a lower microwave band. This combination joins together the capacity advantages of E-band with the high availability of lower bands, such as 18 or 23 GHz. We have demonstrated the tremendous advantages provided by our all-outdoor, single-box WTM 4800 Multi-Band solution. However, the Multi-Band concept can be applied to a combination of microwave-only bands, as well as to all-indoor radio architectures for ANSI applications, such as provided by Aviat’s all-indoor IRU 600.
Combining two microwave bands on one link benefits applications that struggle from a lack of spectrum availability in one band, or tower footprint issues. In addition, spectrum fee savings are possible from using a higher band, such as 11 GHz, in addition to a lower band such as 6 or 7 GHz. In the USA, where 6 GHz is heavily used for microwave point-to-point links and is now sharing the spectrum with Wi-Fi, Microwave Multi-Band offers an effective way to achieve higher link capacities with lower total cost of ownership (TCO), while also minimizing the use of the 6 GHz band.
Higher frequency bands often allocate much more bandwidth per channel. In 11 GHz, channels can be up to 80 MHz wide, offering an extra 33% more capacity than a 6 GHz 60 MHz channel, and up to 166% more capacity compared to a 30 MHz channel.
An emerging issue with 6 GHz is that new unlicensed devices (WI-FI 6E initiative) are now allowed to operate across the entire band, threatening current and future deployments in this band. This does not apply to 11 GHz, making it an ideal parallel channel to increase the available throughput of a link. Along with an option for capacity growth, 11 GHz also provides a second channel immune to potential interference, which offers protection and a form of spectrum diversity in case the 6 GHz link is impacted.
For Ethernet-based links, radios can combine the throughputs of multiple microwave channels using a protocol called “layer 1 link aggregation” (L1LA) into a single ethernet pipe. This protocol can be accomplished with radios at different frequency bands, thus enabling the seamless combination of high throughput and reliability, using the higher availability of the 6 GHz and the higher throughput of 11 GHz.
A second focus looks at the economics of the antenna and how the total cost of ownership (TCO) associated with antennas is a key criterion for network designs. For customers who lease tower space, the recurring cost (OPEX) is calculated on the leased vertical space on the tower based on the size of the antenna. The smaller the size of the antenna, the lower the monthly fee. For customers who own towers, the size of the antenna can still have a cost impact depending on the tower loading capability of the structure. Tower regulations also impose newer, more stringent requirements on towers that apply to larger antennas and add significant costs for analyses and potential modifications.
To simplify deployments and reduce costs, using fewer and smaller antennas is a smart decision. In the past deploying two separate frequency bands on a single link would have required an antenna for each band to be installed, adding cost and deployment complexity.
However, an antenna is now available that supports both 6 and 11 GHz in a single common reflector, with multiple RF ports. With this new antenna 6 plus 11 GHz Multi-Band links can now be implemented as easily, and as cost-effectively, as a 2+0 6 GHz link.
Aviat’s IRU 600 all-indoor radio provides a simple solution for 6+11 GHz Multi-Band links. With a modular chassis design, a single 2RU indoor radio can be equipped with one 6 GHz and one 11 GHz transceiver, plus the associated branching and filtering, with an individual waveguide antenna connection for each band. The IRU 600 also can be configured with Extra High Power (EHP) capability for the 11 GHz channel, so that it can support availability approaching that of the 6 GHz path.
The combination of Aviat’s market-leading ultra-high power IRU 600, with Multi-Band 6+11 GHz capability, all with a single antenna is a great option to alleviate channel availability issues at 6 GHz, reduce the potential of WI-FI 6E related interference issues, while also minimizing the tower related TCO, while also supporting a high capacity, mission-critical microwave link.
Here are my contact details