- Installing beacons
- Transmission Power and Advertising Interval
- How to check that all areas have been covered?
In this section of the documentation, we will explain in detail how Situm recommends placing the beacons.
Installing beacons #
Where and how to attach beacons #
- The beacons can be installed on the walls, ceilings or other elements of your building.
- If you’re going to install them in columns, please take into consideration the signal’s emission radius: the strength of the signal might be noticeably less on the opposite side to which the beacon is installed in.
- We recommend avoiding placing beacons on smooth surfaces such as: metal coated walls, columns or panels, windows or glass surfaces, PVC, or other types of plastic surfaces.
- Usually, you will be able to attach them through an adhesive that they carry on their back part (some beacons also allow you to screw them to the wall).However, you may also attach them by way of adhesive paste or even Velcro panels.
- We recommend to not install them near sources of electromagnetic emission, such as WiFi APs, operating machines or electrical panels.
- We also suggest to place them at a between 2 and 3 meters height.
How to distribute beacons #
Generally, you should distribute your beacons so that you:
- Cover as much space possible while respecting at least the minimum number of beacons recommended (see below some of the tips).
- All areas are covered at least by the signal of 2 or 3 beacons.
- The imaginary perimeter formed by the outer beacons of each floorplan encloses all the areas that you want to cover.
More specifically, follow these tips for placing beacons in typical areas:
Open areas #
Place the beacons in the outer walls, drawing, if possible, a zig-zag pattern. Beacons should not be more than 15-30 meters away from each other. If walls are very far away from each other, you will need to place a few beacons in the middle of the open area, as evenly distributed as possible.
If possible, place the beacons in the middle of the corridor, evenly distributed every 15-30 meters.
Small rooms #
Like offices, meeting rooms, etc. Depending on the size of the room, one beacon might be enough.
However, these are not the only areas in which a beacon could be placed. Depending on your use case, you might have to place them in:
Place beacons on a zig-zag type of pattern, but always on the corridors of the parking, which is typically where people would pass through. We recommend that you configure their transmission power to the maximum: +4 dBm.
Same as described above, and whenever possible, place the beacons in the ceiling, centred in the corridor, and evenly distributed.
Double Narrow Corridor #
In some places, like Airports, you might need to discriminate between two different sides of one corridor. These areas are typically only divided by a glass. In this case, you will want to install the beacons at the same height and distance in either side of the corridor and attach them on the walls opposite the glass.
Optimising beacon placement for floor detection #
If your building has more than one floor, it is important to place beacons close to each floor’s changing point (elevator, stairs), to help Situm detect the new floor as soon as the user arrives at it.
Moreover, it is important to place beacons facing the floor change point so that the signal is stronger. You may play with the transmission power of the beacons here so that floor detection is quicker.
Transmission Power and Advertising Interval #
There are two relevant beacon configurations regarding deployment & maintenance.
- Transmission Power (Tx Power). Influences:
- Signal Range.
- Advertising Interval
The settings you choose will have a large impact on how your beacon network will operate once deployed. However, choosing the best settings is greatly determined by your use case or any specific needs you may have, and so, you will need to keep in mind that the settings you choose will have an effect on the following things:
- Signal Range (influenced mostly by Tx Power).
- Signal Stability (influenced more by the Advertising Interval than by Tx Power).
- Battery Life (influenced more by the Advertising Interval than by Tx Power).
Choosing the best Transmission Power #
All beacons, regardless of manufacturer, allow you to customize their transmission power. This power is measured in ‘dBm’ (Decibel-milliwatt), which is a unit of measure to gauge the strength of radio frequencies.
Transmission signals from a beacon expand outwards like this:
Where the relationship between distance and Tx Power follows an inverse square law where each tier represents a doubling (or halving) of power.
Therefore, Tx power does not just affect the range within which another smart device (I.e., a smartphone) can pick up the transmission but it also affects the battery life of a beacon. The lower the
dBm power of a beacon, the more targeted of an area you can create. However, increasing the dBm to increase range is not as efficient.
There are many reasons to want to decrease the Tx factor of your beacon:
- You typically want to prevent regions of beacon coverage from overlapping.
- You may also want to deploy beacons which broadcast different types of packet data based on proximity.
There are also reasons to increase the Tx factor of your beacon:
- Stronger signal strengths have less margin for error when estimated the distances between two or more Bluetooth devices.
- If you are using beacons for proximity and location determination, higher Tx signals are necessary and overlap between regions is less problematic.
However, the best way to determine the Tx Power that better suits your needs is to target these:
- Analyzing your building’s infrastructure, square footage, and environmental uniqueness to determine how much beacon range you really need.
- Your willingness to change the beacon’s battery often
- Knowing when you really need to use a higher Tx Power and when not to. For example, the following scenarios may justify the use of a higher power:
a. It is important for the beacon to be found or ‘heard’ by as many people as possible.
b. There is a lot of potential interference in the immediate vicinity of the beacon (e.g., thick steel panels, brick walls, or other dense objects) so you need a powerful signal to cut through this interference.
Beacon installation recommendations regarding Tx Power:
Here are some best practices of using Tx Power to get the best possible performance and battery life:
- If you need the signal range to be as wide as possible in a high traffic area, use a higher power setting
- If you only need the beacon to be detected a few meters away, use a lower power setting.
- Install the beacon roughly 2 meters up from the floor, to reduce interference from people walking by.
- Always be mindful of “line-of-sight” i.e., that in general, there are no objects in between a beacon and the customer’s smart device.
First, I think we need to understand that beacons do not broadcast constantly. They sort of ‘blink’ instead. The advertising interval, therefore, is the time between each ‘blink’, or how often your beacon will transmit its advertising packet (i.e., basically telling nearby devices where it is). This is usually measured in milliseconds (ms) but can also be measured in seconds (s) at the very highest interval ranges.
Choosing the Best Interval Setting #
Therefore, the lower your advertising interval rate, the more often the beacon will transmit its ‘blinks’. As you might have guessed, this has a high impact on the battery life of your beacon.
The current standard for the iBeacon profile (I.e., the settings recommended by Apple), which is 100 ms, reduces battery life substantially and in reality, there are many cases where such a low interval is unnecessary.
Apple’s reasoning behind this is that such a setting is based on achieving high signal stability and highly accurate indoor positioning, but these reasons are arguable, mostly because of the fact that even when setting up your beacons to transmit at such a low interval, it doesn’t mean that an iPhone can respond to that signal with the same speed. iPhone currently scans every one (1) second due to system limitations and decreasing your interval won’t change that: it will only increase the chances of a device (smartphone) managing to grab one signal out of a few transmitted within this second.
On Android devices, on the other hand, there is no such limitation, which means that theoretically they could grab and react to the beacon signal in seconds. This, however, has a high impact on smartphone battery drainage.
How does beacon Interval affect Signal Stability? #
During our rounds of installations and calibrations in different types of buildings, we’ve found that higher interval settings cause major issues with signal stability. In this same way, using lower intervals doesn’t help much either, only in certain tricky areas.
Overall, we’ve determined that 750ms offers the perfect balance between signal stability and battery life, which is why we recommend this setting as a default option.
How does Interval affect indoor positioning? #
However, there may be some cases in which you would want to sacrifice battery life for the sake of indoor positioning accuracy. It will all depend on how accurately you need to determine the positioning of a device (or smartphone-carrying person, in this case) interacting with your beacon network.
For example, if you want to know the positioning of a person traveling at a normal walking speed there isn’t much difference in accuracy between 100 and 650 ms, just the impact on battery drainage.
On the other hand, in this same scenario, if the interval is set up to 1000 ms (or 1s), the positioning accuracy drops substantially and cannot tell precisely which way the person is going. It really depends on your use case.
Then, when should you use a low interval (understood as 100 ms or less)? There are some cases that could be worth the risk of sacrificing battery life:
- The tracked object tends to move quickly, I.e., a moving car
- You need to know the object’s location by centimeters rather than meters.
Beacon Installation Recommendations regarding Advertising Interval: #
If the above-mentioned particular scenarios do not apply to your use case, then we highly recommend using an interval between 700 and 800 ms for the majority of deployments. Anything lower will drain your battery quicker than you’re willing to change it and, anything higher may have performance issues due to signal instability.
How to check that all areas have been covered? #
Once the beacons are installed we will go to the Dashboard and we will be able to know both the location of the beacons and if we have covered our building correctly with the beacons.
Location of beacons #
To find out the location of the beacons, we go to the Infrastructure panel and all the beacons listened to in that building will appear. For this, we will have to calibrate the areas where the beacons have been installed to add them to the model.
Beacons coverage map #
To find out if we have covered a beacon area well, we go to the Dashboard configuration panel and select in Positioning Model the floor of the building that we want to check. Later we click on Visualize model and we can see if all the areas of interest are covered.