Overview

This article describes the workflow for deploying Aruba Access Points (AP) and control tags to support Meridian asset tracking.   

Similar to AP deployment for Wi-Fi systems, it can be difficult to predict the radio wave propagation or detect the presence of signal interference without the use of proper deployment strategies or test equipment. Obstacles such as walls, doors, glass, metals and others physical properties may contribute some degree of attenuation or reflection, causing the RF radiation pattern to be irregular and unpredictable. Since BLE uses RF, it is susceptible to multi-path propagation problems just like Wi-Fi.

Whereas the goal for deploying Wi-Fi systems is for enabling wireless mobile connectivity for computing devices, the goal for deploying BLE is for location services. Aruba Access Points are mainly deployed for wi-fi systems to enable a wireless mobile device to connect to the internet.  However, with the integration Bluetooth Low Energy (BLE) radio, it can also be deployed for location services, such as blue dot wayfinding and asset tracking. 

There are a good amount of information and knowledge base along with site survey software and tools for deploying APs for wi-fi.  This article will mainly focus on deploying and placing APs for Meridian asset tracking.

Benefits of Access Point Beacons

The Internal BLE was not a part of the Aruba APs until the AP-300, AP-203R and AP-303H series Access Points.   Prior to the AP with internal BLE (APB), Meridian location services was relying on the battery powered beacons for blue dot wayfinding and did not have a way to track tags.  

Battery powered beacons have its advantages. They were easy to deploy because they can be place anywhere without having to run cables or power. However, they have a limited battery life and are not able to communicate beacon status back to Meridian servers. Having a reliance on battery may limit its placement in environments with extreme temperature conditions as well.

Using APB not only did away with the beacon's reliance on battery but it can operate as a beacon sensor to monitor and report status of surrounding beacons to the Meridian server. This ability to listen for beacons was then extended to listen for BLE tags, hence the ability to track asset tags.

With the evolving capabilities and use cases for BLE, the Aruba AP deployment plan not only has to consider blue dot wayfinding, it also needs to evolve to account for asset tracking.

Supporting Meridian Location Services After the APs Have Already Been Installed

This section describes the workflow for deploying Aruba Access Points (APs) and control tags to support Meridian asset tracking after the APs have already been installed.

Asset Tracking Deployment Guidelines

Below is a list of things to consider when deploying to support asset tracking:

• The accuracy of Meridian Asset Tracking is directly related to the density of the AP deployment. The Asset Tracking Performance article provides a breakdown of the accuracy, latency, and stability you can expect based on the AP density you deploy.
• As a recommended approach, it's advisable to implement as many control tags as possible before initiating asset tracking to assess the precision of the environment.
• To track assets along a corridor, deploy APBs configured as Observers in a straight line down the center or along the corridor. An Observer = an APB that has the AP Beacon configured as either a Location or Proximity beacon AND the Asset Tracking IoT Profile defined. An asset tag can be tracked if heard by 1, 2, or 3 Observers. Tag tracking accuracy is more accurate if heard by at least 3 Observers.  If there are APBs in and adjacent rooms to the corridor, but asset tracking is not required in that room, I would be best to not configure the beacons on those APs. If an APB is not configured, it will not operate as an Observer.
• To track assets in an open room, first, deploy APBs in the corners, second along the perimeter of the room, and third fill in the center of the open area.  
• If accuracy is not required in the room but knowing the tag is in the room is good enough, then a single APB in the center of the room should be sufficient.
• Never place a control tag outside the perimeter of the APB triangle perimeter. 

Workflow for Deploying APs and Control Tags for Asset Tracking

The steps below will guide you through the best approach for deploying the APs and control tags to support asset tracking after the APs have been deployed.

Step 1.  Analyze Current AP Placement

All Aruba AP deployments up to this point have only considered best practices for wi-fi.  Whereas this is great for wireless connectivity, it may leave some gap for asset tracking.   This doesn't mean that you have to rip them out and re-deploy.  As long as the APBs are deployed for optimal Wi-Fi connectivity, approximately 50 feet apart, additional APs can be used to fill-in and augment for improved tracking of asset tags.

Listening and reporting tags to Meridian server is a functionality of the APs, not beacons.  After the data is sent to Meridian server, asset tracking is then done on the Meridian server and the location of the tag is stored for later retrieval.   If you have previously deployed beacons for wayfinding, the beacons are not part of the asset tracking solution.  Here, it is all about the AP placement in your environment for accurate asset tracking.  

The map below shows a very good AP deployment for wi-fi, however, there are a few problem areas if you intend to track tags.

Note:  The grid lines are 30 ft apart.  This examples below may have a denser deployment than typical because APs were used for various tests.  This is an exception and not a requirement.

Take a look at where your APs are currently deployed to quickly assess where you can track tags in your environment.  In the map below, the red line represents the outer perimeter of the APs.  Tags can only be tracked inside this AP perimeter.    Beyond the outer AP perimeter is the red zone where tags cannot be tracked.  For example, if a tag was to be placed outside of the outer AP perimeter, in the red zone, the system could only determine that the tag is between the closest APs, similar to how a blue dot is shown between beacons.  

Step 2.  Identify Where the Tags Are to be Tracked

In this example we are interested in tracking the tags in the Tag Zone, marked with the green rectangle, but in reality the tag can only be tracked in the actual tracking zones marked with the blue polygon - the area inside the perimeter of the nearest APs.  

Step 3.  Augment with APs for Additional Coverage

If tag tracking is required in all of the Tag Zone area, then additional APs will need to be deployed or existing APs moved to bring that area inside the AP perimeter, as shown below.  This change will ensure that you are able to track the APs in the desired location in the building.

Step 4. Troubleshoot Using Control Tags for Improved Accuracy

Meridian provides an additional feature to quantify the accuracy of tag tracking in a specific areas.    In the physical world, building materials and signal interferences may obscure the data that is use by the Meridian location engine to track a tag. The control tags is a tag way to fingerprint the environment with know locations of a reference tag.  A control tag is an asset tag that is place on the map at a known location so that is can be compared the location that the location engine thinks it's at based on the data received by the APs in the area.

A control tag is an asset tag that is placed on the Meridian map.  
It is the same hardware as a normal tag, but configured differently.

For more information about configuring control tags, see:  Deploying Asset Tags and Control Tags

Planning AP Deployment for Asset Tracking

If tag tracking was required in all areas of this floor then additional APs should be added in the areas with the red circles:

The red circles represent areas where APs should be place to increase the tag tracking area.  It is best to start with the corners, fill in the perimeter gaps, and then fill in the center.  From a wi-fi placement perspective, this is not a typical deployment plan.  

Summary

The mobile app relies on the the ABs placed in the environment to listen for the tag and report that data to Meridian server.  It seems like you should be able to deploy APs anywhere and let the app figure it out, but the Meridian server does not a have a spatial awareness to track the tags outside of the AP perimeter.  To ensure the best tag tracking, it is critical that the APs are deployed in the locations as described above. 

If the system does not work as expected after completing all the steps described above, you may contact us as https://asp.arubanetworks.com/.