June 2, 2021

Stretching 11 GHz Links for Higher Capacity without Compromises

In this highly digitized broadband world, the demand for network capacity is always rising. Wireless internet service providers and mobile operators are all finding their customers demanding more bandwidth. Even utilities and local governments use more network bandwidth as they deploy surveillance cameras and other high-demand applications. Long-haul microwave links play a key role in delivering network capacity, and 6 GHz and 11 GHz frequencies are popular choices.

In North America, 6 GHz has always been the primary frequency band for long-haul backhaul links (i.e., greater than 10 miles), but it’s a victim of its success in some ways. There have been a lot of 6 GHz licenses obtained and activated recently, and now Wi-Fi 6E is going to use some of that spectrum as well. Users must now deal with congestion on that frequency, and the congestion impact is worse with higher-capacity configurations such as dual-channel (60MHz) 6 GHz deployments.

The 11 GHz frequency is more readily available and delivers more network capacity, over 700 Mbps in an 80MHz channel, than 6 GHz’s 250 Mbps in a 30MHz channel. So it seems like a good solution for significantly increasing network capacity. The problem is that 11 GHz is typically used for short-to-medium distance links under 10 miles because it can be susceptible to rain attenuation. Because the higher the rain level, the greater the attenuation and the shorter the 11 GHz path has to be.

To compensate for the degraded signal during rain on an 11 GHz path, you need to increase the signal strength to overcome the degradation level. There are two widely-used methods to increase signal strength:

• increase the antenna size, which improves performance but also increases Total Cost of Ownership (TCO) because of higher space/leasing costs on the tower; or
• increase the transmit output power of the radio to compensate for the path losses without having to use a larger antenna.

The Multi-Band Solution

Now, there’s a way to combine these two bands to get the best of both worlds. Aviat’s IRU 600 Extra High Power (EHP) multi-band 6 GHz/11 GHz radio combines the higher reliability of 6 GHz with the capacity of 11 GHz to increase customer options for network expansion. Customers can use 11 GHz for higher capacity while putting more reliability-sensitive traffic on the 6 GHz band (which offers Five Nines – 99.999 percent – reliability).

As the comparison in Figure A shows, an 11 GHz, 15-mile link equipped with IRU 600EHP radios (denoted “Replacement Option B”) can reach a distance comparable to a 6 GHz MW link. (As a frame of reference, Figure A shows options with four, six, eight, and ten-foot antennas.)

EHP Equals more Flexibility

Figure A

While specific path calculations will be needed to validate the exact deployment scenario, this example demonstrates that 11 GHz is now a more viable long-range solution with an EHP radio in cases where 6 GHz channels are not available.

Maintaining Low TCO

If possible, customers want to increase network capacity without increasing TCO. Today’s abundance of networking equipment inside the shelter or cabinet and on the tower makes it necessary to find ways to decrease the equipment footprint. Adding an extra equipment rack, a bigger cabinet, or bigger or multiple antennas on the tower unnecessarily increases the TCO of the network.

Aviat’s solutions all contribute to lower network TCO by reducing the total footprint of microwave equipment in every site. The IRU 600 EHP chassis can house both 6 GHz and 11 GHz RFUs (or two RFUs of either channel) along with microwave filters in a single chassis and a single INUe, so it requires no extra footprint in the shelter.

With Aviat’s IRU 600 EHP multi-band radio, 11 GHz becomes a truly viable option for extending network capacity over long distances without compromising the reliability of having a 6 GHz path on the same link. For more information about the IRU 600EHP, contact us today!