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airOS LTU v1.1.2 for AF-5XHD Now Available

Hi everyone,

We recently released airOS LTU v1.1.2 for the AF-5XHD. This release is a real milestone for the product, as it introduces several powerful and long-awaited features that will help to make your network faster, easier to operate, and more resistant to interference. Here are some of those key features:

Frequency Split

As more and more networks are deployed worldwide in the 5 GHz band, the ability to make the most efficient use of the available spectrum is critical. In some environments, the sources of noise and interference may not be the same for both ends of a wireless link. A channel that is clean at one location may be cluttered at another, and vice versa. In these cases, the ideal solution would be to use one channel to transmit, and another to receive. This gives network operators substantial flexibility in how they arrange their channel plan, allowing them to increase network reliability and performance without requiring any new hardware.

In airOS LTU v1.1.2, this feature is now available for the AF-5XHD. Separate frequencies for transmit and receive can be easily configured using the airOS LTU web user interface, and we expect to see a lot of network operators trying it out in various challenging conditions over the coming weeks.

In the screenshots below from one of our live links, Frequency Split is giving the link a 30% boost in performance. The first screenshot below shows a 21km link in a noisy environment with Frequency Split turned off:

The second screenshot shows the same link with Frequency Split turned on, using the Best Frequency Hint feature (described below) to choose the optimal channel. This results in a 30% performance increase and solid data rates:

4096 QAM (12x) Support

Since LTU was first announced, one of its headline features has been the extraordinarily high spectral efficiency that this innovative, custom-built silicon makes possible for the WISP, even in the 5 GHz band. Starting with 1024 QAM (10x) support, the AF-5XHD has been the only WISP product available that allows network operators to keep pushing their links above 256 QAM, and delivers unmatched spectral efficiency. Now, with airOS LTU v1.1.2, we’re taking it further with 4096 QAM.

4096 QAM requires an incredibly dense constellation to function and provide error-free, high data rate performance. To support 4096 QAM, the ordinary software-defined radio won’t cut it; everything from power supply noise to how signals are amplified must be finely tuned, tweaked and perfected. In addition, only an LTU RF front-end designed for the task can handle it today.

With 4096 QAM, wireless links that meet the SNR and signal quality requirements can see a significant boost in data rate with just a software upgrade to both ends of the link. Here’s a screenshot from one of our live links running 4096 QAM (12x):

And just take a look at the results table below to see the difference that 1024 and 4096 QAM make over 256 QAM:

Link Frequency Selector

When you operate a wireless network, especially at the time of deployment, few choices are as critical as your choice of channel. For all the time network operators spend choosing the right radio, aligning the antenna, and combing through settings, you can still be operating on a non-optimal channel without realizing it. To help network operators everywhere get the best network performance with the least amount of fuss, we’ve introduced a new feature.

The Link Frequency Selector shows both the local and remote RF environments, and helps the network operator to quickly and easily select the best channel. Through a combination of the spectrum data from both ends of the link, this feature shows you which frequency is optimal.

In the screenshot below, you can see an example of the new Best Frequency Hint feature. This feature uses a dynamic calculation that is continually performed on spectrum data to always recommend the best frequency to use for the link. It also works with Frequency Split, and will recommend the ideal frequency to use for each end of the link independently of the other.

Seamless Frequency Changes

Changing to another, less cluttered frequency can often be the best boost in performance you can give your network. But making the switch usually comes with issues; primarily, when you change frequency, your wireless link will have some downtime. There has to be a better way, and there is it’s the new Seamless Frequency Changes feature implemented in airOS LTU v1.1.2.

With Seamless Frequency Changes, whether your wireless link changes to another frequency because you’re using Frequency Split, Alternative Frequency, or Auto Frequency, it doesn’t matter. Even during a frequency change, your link will not drop or disconnect. This drastically reduces your downtime and makes network maintenance easier and less troublesome than ever.

Centralized Link Management

When configuring a PtP link, it can be time-consuming to create nearly the same configuration on both ends of the link. This is especially true when you have many links in the field, and you may have to configure each of them in a specific order to avoid losing access to remote units.

With Centralized Link Management, our goal is to save you time and effort in configuring and managing your network. This feature lets you treat both ends of your link as one, so you can manage the link from the master side rather than individual devices. Any configuration changes marked below that you make to the link are performed across both devices, all automatically.

What’s more, this feature is enabled by default and also applies to firmware updates. If the wireless link is down, you can still configure each standalone device as you have in the past.

Smart Assistant

In keeping with the theme of saving you time and effort in operating your network, our new Smart Assistant feature is designed to help speed up troubleshooting. On the Dashboard, an Alerts menu now shows a list of issues airOS LTU has detected with your link. You can click on each one to see a brief description, as well as some quick troubleshooting steps you can take for it:

By clicking on these alerts, you can see the list of troubleshooting steps:

Or, by clicking directly on a highlighted issue, you can review and fix the relevant configuration:

In the first stage of this exciting new feature, the Smart Assistant will monitor and alert you of errors and warnings that are often encountered in real-world networks, such as a missing GPS signal, Ethernet negotiation failures, or a lower than expected signal strength. For each of these issues, the Smart Assistant will give you some troubleshooting steps on how to fix the problem.

In the second stage, to come in a later firmware release, the Smart Assistant will have access to more detailed information about the wireless link and be able to respond to link capacity drops, interference and other issues, and will provide help on making the best use of the spectrum.

Auto Frequency

This feature is currently in beta, but it’s already proving to be effective at keeping wireless links working smoothly for many network operators around the world. With Auto Frequency, you don’t need to manually specify alternative frequencies in case of a DFS event, keeping your network performing better with less of your time required for configuration. And because of Seamless Frequency Changes, frequency changes can occur without your link dropping or disconnecting.

Other Updates

As well as these features, airOS LTU v1.1.2 includes several more features and fixes as well:

  • Traffic prioritization based on DSCP/ToS bit values
  • Auto rate recovery improvements
  • Improved 4 and 5 ms stability under interference
  • Wider channel stability improvements

Thank you for your continued interest and support in our products. To download v1.1.2, go here:

To view the full change log for v1.1.2, go here:

We look forward to hearing all of your experiences and feedback on this release and more on both the Official Ubiquiti ISP Professionals Facebook group, and on the Ubiquiti Community, where you can also get quick help and discussion. We’re always listening to your feedback!