A common question is how to evaluate if Kontakt.io Portal Beams are in sufficient proximity to Portal Lights (BLE to Wi-Fi gateway infrastructure devices). The Bluetooth Low Energy (BLE) Received Signal Strength Indicator (RSSI) value serves as a tool to evaluate the distance between these devices. Although not remarkably precise on its own, it offers a fundamental understanding of the relative closeness or distance between a transmitting device (Portal Beam) and a receiving device (Portal Light).
In this article, you'll learn about using BLE RSSI measurements to evaluate the proximity between Kontakt.io Portal Beams and Portal Lights. This information can be used to assess whether you have the appropriate density of Portal Lights to effectively support your Kontakt.io solution and its use case.
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BLE RSSI is a measure of the BLE signal of a transmitter (Portal Beam) as seen by a receiving device (Portal Light; BLE to Wi-Fi gateway). When a receiver scans for Kontakt.io BLE devices, the Bluetooth radio inside the device provides a measurement of the RSSI for each seen packet. It's measured in decibels, dBm, on a logarithmic scale and is negative. A more negative number indicates the device is further away. For example, a value of -60 dBm indicates the a BLE device is close to the receiving device while a value of -≤ -85 indicates the BLE device is near the limit of detection.
Maintaining a desired RSSI level is important to ensure communication between the transmitting and receiving devices. Keep in mind that while the BLE RSSI provides a basic indication of proximity, it's not a linear measurement and can be influenced by other factors.
The following details should help you quickly assess the proximity of a Portal Beam (transmitter) to a Portal Light (receiver) based on the BLE RSSI measurement observed.
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The signal is always better when the RSSI value is closer to -60. For example, a pretty good value is -70, while -85 indicates a weak signal.
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As the RSSI value decreases (becomes more negative), the proximity (distance) between the devices tends to increase. A more negative RSSI value ( ≤ -85 ) will result in less reliable data.
It's important to note that the actual performance of a BLE connection is influenced by factors beyond just RSSI, including interference, noise, and the specific use case. Additionally, the distances corresponding to these BLE RSSI ranges can vary based on factors such as the transmit power of the BLE transmitting devices and the surrounding environment.
|
BLE RSSI Range (dBm) |
Signal Strength |
Definition |
|---|---|---|
|
> -60 |
Excellent |
Very strong signal; devices are very close and ideal for packet scanning, configuration and firmware updates |
|
≥ -60 and ≤ -85 |
Good |
Strong signal; devices are relatively close and suitable for packet scanning, configuration and firmware updates |
|
≤ -85 |
Weak |
Very weak signal, high chance of packet loss |
Consider the following example of the telemetry data for a Portal Beam. In this instance, the recorded RSSI value is -96. Unfortunately, this value is notably weak and falls below the recommended RSSI range for both firmware and configuration updates. Given that the RSSI value is -96, it's too weak for stable communication.
```json" trackingId": "00:fa:b6:0b:b3:47", (Portal Beam MAC address;transmitter) "timestamp": "2023-07-25T08:03:00Z", "batteryLevel": -1, "channel": 38, "humidity": 21," lightIntensity": 25, "rssi": -96, (BLE RSSI measurement) "sourceId": "132n00HP" (Portal Light Unique ID;receiver)
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Kontakt.io API. Retrieve telemetry by tracking ID (tag or room sensor MAC address). Provides the last received RSSI measurement of the receiver (Portal Light)
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Kontakt.io API. Retrieve telemetry by source (Portal Light Unique ID). Provides the last received RSSI measurement for each tracking ID (BLE tag or room sensor) scanned by the Portal Light.
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Kio Setup Manager app. Provides the real-time BLE RSSI measurement of the BLE device in proximity to your mobile device (acting as the BLE receiver).