From ccbc9448442468a6d5a933f0bb41f30b73b8385a Mon Sep 17 00:00:00 2001 From: Eric Anderson Date: Tue, 25 Jul 2023 10:42:02 -0600 Subject: [PATCH 1/2] Clarify LinkADRReq parameters The original definition was for the wrong kind of "bandwidth," and while I was making that change I got sucked into adding a little more explanation, and including the Redundancy parameter --- .../learn/05.communication/05.lorawan-101/lorawan-101.md | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/content/learn/05.communication/05.lorawan-101/lorawan-101.md b/content/learn/05.communication/05.lorawan-101/lorawan-101.md index 17f6f5c800..03bc47019a 100644 --- a/content/learn/05.communication/05.lorawan-101/lorawan-101.md +++ b/content/learn/05.communication/05.lorawan-101/lorawan-101.md @@ -70,9 +70,10 @@ Communication between end-devices and gateways in LoRaWAN® networks is spread o To maximize the battery life of each end-device and the overall capacity available through the network, LoRaWAN® uses an **Adaptive Data Rate** (ADR) mechanism for **optimizing data rates, airtime, and power consumption**. ADR controls the following transmission parameters on end-devices: -- **Spreading factor**: the **speed of data transmission**. Lower spreading factors mean a higher data transmission rate. -- **Bandwidth**: the **amount of data that can be transmitted** from one point to another within the network. -- **Transmission power**: the energy that the end-device transmitter produces at its output. +- **Spreading factor**: the **speed of data transmission**. Lower spreading factors mean a higher data transmission rate, but lower range and link budget. +- **Bandwidth**: the **the amount of radio-frequency spectrum used** for the transmission. Higher bandwidth mean a higher data rate, but potentially more inference and lower range/link budget. +- **Transmission power**: the energy that the end-device transmitter produces at its output. Higher power means more range and link budget (lower error rates), and _allows_ increased data rates (via raising bandwidth and/or lowering spreading). +- **Redundancy**: the number of times each message is repeated. Higher redundancy means a much lower (effective) data rate, but some improvement in reliability. The table below shows compares spreading factor, data rate, and time on-air at a bandwidth of 125 kHz (range is an indicative value, it will depend on the propagation conditions): @@ -299,4 +300,4 @@ LoRa® and LoRaWAN® are pretty extensive but exciting topics to study. If you w - [The LoRa Alliance® Resource Hub](https://lora-alliance.org/resource-hub/). Here you can access LoRaWAN® technical documents and Whitepapers from The LoRa Alliance®. - [LoRa Developer Portal from Semtech](https://lora-alliance.org/resource-hub/). Here you can find technical papers and user guides as well as specifications and datasheets from Semtech. - [The Things Network documentation](https://www.thethingsnetwork.org/docs/). Here you can learn all about LoRaWAN® and The Things Network! -- [The Things Academy online course in Udemy](https://www.udemy.com/course/lorawan-fundamentals/). A free online course where you'll learn all about LoRa® and LoRaWAN®, and get ready to start building your own Low Power Wide Area Network applications. \ No newline at end of file +- [The Things Academy online course in Udemy](https://www.udemy.com/course/lorawan-fundamentals/). A free online course where you'll learn all about LoRa® and LoRaWAN®, and get ready to start building your own Low Power Wide Area Network applications. From 1f37fc3048da14734018f7b1043511a90a946afc Mon Sep 17 00:00:00 2001 From: Eric Anderson Date: Tue, 25 Jul 2023 11:07:48 -0600 Subject: [PATCH 2/2] LoRa: Added a little description and citation Explained a little more about how data rate control works --- content/learn/05.communication/05.lorawan-101/lorawan-101.md | 2 ++ 1 file changed, 2 insertions(+) diff --git a/content/learn/05.communication/05.lorawan-101/lorawan-101.md b/content/learn/05.communication/05.lorawan-101/lorawan-101.md index 03bc47019a..3aed56c460 100644 --- a/content/learn/05.communication/05.lorawan-101/lorawan-101.md +++ b/content/learn/05.communication/05.lorawan-101/lorawan-101.md @@ -75,6 +75,8 @@ To maximize the battery life of each end-device and the overall capacity availab - **Transmission power**: the energy that the end-device transmitter produces at its output. Higher power means more range and link budget (lower error rates), and _allows_ increased data rates (via raising bandwidth and/or lowering spreading). - **Redundancy**: the number of times each message is repeated. Higher redundancy means a much lower (effective) data rate, but some improvement in reliability. +Note that spreading factor and bandwidth aren't independently configurable, rather the "Data Rate" parameter is an index into a table of pre-defined "bandwidth + spreading factor (and sometimes other modulation parameters)" configurations. Transmit power is configured separately, also through a lookup table. Note also that there are *different* tables for different frequency bands and regions/regulators. For example, in the US 902 - 928 MHz band, "data rate" 3 corresponds to a 125 kHz bandwidth with SF7, and "data rate" 4 is 500 kHz with SF8 (see [RP002-1.0.4](https://resources.lora-alliance.org/technical-specifications/rp002-1-0-4-regional-parameters) Table 15). + The table below shows compares spreading factor, data rate, and time on-air at a bandwidth of 125 kHz (range is an indicative value, it will depend on the propagation conditions): | **Spreading Factor** | **Data Rate** | **Range** | **Time on-Air** |