exploring_lora
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exploring_lora [2018/09/29 12:51] – [3.1. Modifying the Radio Parameters] samer | exploring_lora [2018/09/29 13:35] – [4.1. Time on Air] samer | ||
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As defined by Semtech, [[http:// | As defined by Semtech, [[http:// | ||
- | In this lab, you will implement a prototype of LoRa communication between two wireless | + | In this lab, you will implement a prototype of LoRa communication between two wireless |
<WRAP center round help 100%> | <WRAP center round help 100%> | ||
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* What is the relation between processing gain and spreading factor in LoRa modulation? Explain. | * What is the relation between processing gain and spreading factor in LoRa modulation? Explain. | ||
* How does the spreading factor impact the coverage of a LoRa transmitter? | * How does the spreading factor impact the coverage of a LoRa transmitter? | ||
- | * For each of the three possible configurations of your LoRa module, what is the transmission bit rate? Explain your computation. | + | * For each of the three possible configurations of your LoRa device, what is the transmission bit rate? Explain your computation. |
* Compute the receiver sensitivity, | * Compute the receiver sensitivity, | ||
* Compare the computed sensitivity to that provided by the {{ : | * Compare the computed sensitivity to that provided by the {{ : | ||
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==== -. Modifying the Radio Parameters ==== | ==== -. Modifying the Radio Parameters ==== | ||
- | Download the {{ : | + | Download the {{ : |
+ | |||
+ | Take a look at the source code in '' | ||
+ | |||
+ | * Central frequency (freq) | ||
+ | * Spreading Factor (SF) | ||
+ | * Bandwidth (Bw) | ||
+ | * Coding Rate (CR) | ||
+ | * Transmit power (Pow) | ||
+ | |||
+ | <code c++> | ||
+ | rf95.setFrequency(frequency); | ||
+ | // Setup Power,dBm | ||
+ | rf95.setTxPower(13); | ||
+ | |||
+ | // Setup Spreading Factor (6 ~ 12) | ||
+ | rf95.setSpreadingFactor(7); | ||
+ | |||
+ | // Setup BandWidth, option: 7800, | ||
+ | //Lower BandWidth for longer distance. | ||
+ | rf95.setSignalBandwidth(125000); | ||
+ | |||
+ | // Setup Coding Rate: | ||
+ | rf95.setCodingRate4(5); | ||
+ | </ | ||
+ | |||
+ | In order to reduce collisions, configure the central frequency of your LoRa devices | ||
^ Group Number | ^ Group Number | ||
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| | | | ||
- | Note that the radio parameters of your LoRa devices: Spreading Factor (SF), Bandwidth (Bw), and Coding Rate (CR) are configured in the '' | ||
==== -. Running Basic Sketches ==== | ==== -. Running Basic Sketches ==== | ||
- | Now you can compile and upload the client and server sketches on the two arduino | + | Now you can compile and upload the client and server sketches on the two arduino |
[{{ : | [{{ : | ||
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==== -. Time on Air ==== | ==== -. Time on Air ==== | ||
- | In this section, you will measure the Time on Air (ToA) under the three different radio configurations and for different message sizes. The ToA is the time necessary to send a message on the radio interface. | + | In this section, you will measure the Time on Air (ToA) as given by the time necessary to transmit |
- | For this, you can start by implementing a function on the client that measures the time necessary for sending a message. For example, you can use the [[https:// | + | For this, you can start by implementing a function on the client that measures the time necessary for sending a message. For example, you can use the [[https:// |
<WRAP center round help 100%> | <WRAP center round help 100%> | ||
- | * Join commented extracts of your code and explain your approach for computing the ToA. | + | * Describe the scenarios you used for assessing the impact of radio parameters on the ToA. You can join commented extracts of your code. |
- | * Draw a box plot of the ToA under the three different radio configurations and for three different message sizes. | + | * Visualise the experimental results using for example [[http:// |
* Analyze the obtained results and compare with the theoretical computations. You can superpose the theoretical results and the practical ones on the same graph. | * Analyze the obtained results and compare with the theoretical computations. You can superpose the theoretical results and the practical ones on the same graph. | ||
</ | </ | ||
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- | In this section, you will measure the coverage of LoRa modules | + | In this section, you will measure the coverage of LoRa devices |
<code c++> | <code c++> |
exploring_lora.txt · Last modified: 2021/10/20 12:52 by samer