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exploring_lora [2018/09/27 10:33] – samerexploring_lora [2018/09/29 11:40] – [3.1. Modifying the Radio Parameters] samer
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   * How LoRa is compatible with LPWAN requirements and constraints?   * How LoRa is compatible with LPWAN requirements and constraints?
 </WRAP> </WRAP>
-===== -. Hardware Platform =====+ 
 +===== -. Setting the Lab ===== 
 + 
 +==== -. Hardware Platform ====
  
 In order to design and implement experiments with LoRa, you will use the following devices:   In order to design and implement experiments with LoRa, you will use the following devices:  
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   * Give an estimated cost of your platform.   * Give an estimated cost of your platform.
 </WRAP> </WRAP>
-===== -. Software Tools =====+ 
 +==== -. Software Tools ====
  
 Download the following software on your PC: Download the following software on your PC:
-  * RadioHead: The Packet Radio library for embedded microprocessors can be downloaded from [[http://www.airspayce.com/mikem/arduino/RadioHead/]] or from this [[http://www.airspayce.com/mikem/arduino/RadioHead/RadioHead-1.86.zip|direct link]]. +  * RadioHead: The Packet Radio library for embedded microprocessors can be downloaded from [[https://github.com/samerlahoud/RadioHead]]. 
   * Arduino IDE: Specific OS versions can be downloaded from [[https://www.arduino.cc/en/Main/Software]].   * Arduino IDE: Specific OS versions can be downloaded from [[https://www.arduino.cc/en/Main/Software]].
  
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 Note well the location of the library folder on your computer. In the following, you will be required to modify source files located in this folder.  Note well the location of the library folder on your computer. In the following, you will be required to modify source files located in this folder. 
 </WRAP> </WRAP>
-===== -. Installation =====+==== -. Installation ====
  
 Start by plugging the Dragino shields on the Arduino devices and mounting the antennas as shown in Fig. 1. Start by plugging the Dragino shields on the Arduino devices and mounting the antennas as shown in Fig. 1.
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 </WRAP> </WRAP>
  
-===== -. Theoretical Analysis =====+===== -. Theoretical Study =====
  
 In this section, you will perform a theoretical assessment of the performance of LoRa modulation. You will later compare this theoretical results to the experimental ones as in a typical scientific study.   In this section, you will perform a theoretical assessment of the performance of LoRa modulation. You will later compare this theoretical results to the experimental ones as in a typical scientific study.  
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 </WRAP> </WRAP>
  
-===== -. Running Basic Sketches ===== +In the remainder of this lab, you will conduct measurements to validate the obtained theoretical receiver sensitivity. 
-Start by setting the central frequency of the LoRa modules. For this, open the ''RH_RF95.cpp'' file locate in the ''RadioHead'' folder and change the frequency to 868.10 (Group 1), 868.30 (Group 2), and 868.50 MHz (Group 3).+===== -. Configuring and Running the Lab =====
  
-<file cpp RH_RF95.cpp> +==== -. Modifying the Radio Parameters ====
-setFrequency(868.X); +
-</file>+
  
-Download the {{ :example-lora-sketch.zip | basic sketches}} that implement a reliable LoRa communication between the two modules. Open the sketches with Arduino IDE, compile and upload on the two arduino modules, respectively. On the serial interfaces, you should obtain similar results as in Fig. 2 and Fig. 3. The client sends a short message and waits for an acknowledgement message from the server. Both modules output the RSSI (received power in dBm) for each received message.+Download the {{ :sketch-1819.zip | basic sketches}} that implement a simple LoRa communication between the two modules: a client module and a server module. Open the sketches with Arduino IDE.
  
-[{{ :client-iotlab1.png?direct&600 ||Figure 2. Client serial monitor}}] +Start by setting the central frequency of your LoRa modules according to the following table: 
-[{{ :server-iotlab1.png?direct&600 ||Figure 3. Server serial monitor}}]+ 
 +^  Group Number  ^   Frequency     ^ 
 +|       1        |      866.7      | 
 +|       2        |      866.9      | 
 +|       3        |      867.1      | 
 +|       4        |      867.3      | 
 +|       5        |      867.5      | 
 +|       6        |      867.7      | 
 +|       7        |      867.9      | 
 +|       8        |      868.1      | 
 +|       9        |      868.3      | 
 +|       10       |      868.5      | 
 +|       11       |      868.7      | 
 +|       12       |      868.9      |
  
-===== -. Modifying the Radio Parameters ===== 
  
 The typical configuration for LoRa modules consists of 125 kHz sub-channels, a coding rate of 4/5, and a spreading factor equal to 7. You can modify the radio parameters by selecting one of the three available configurations: The typical configuration for LoRa modules consists of 125 kHz sub-channels, a coding rate of 4/5, and a spreading factor equal to 7. You can modify the radio parameters by selecting one of the three available configurations:
  
-  * Bw125Cr45Sf128 +==== -. Running Basic Sketches ====
-  * Bw125Cr48Sf4096 +
-  * Bw31_25Cr48Sf512+
  
-Radio configuration is applied in ''RH_RF95.cpp'' as in the following example: +Download the {{ :sketch-1819.zip | basic sketches}} that implement a simple LoRa communication between the two modules. Open the sketches with Arduino IDE, compile and upload on the two arduino modules, respectively. On the serial interfaces, you should obtain similar results as in Fig. 2 and Fig. 3. The client sends periodically a short message and towards the server. The server outputs the RSSI (received power in dBm) for each received message.
-<file cpp RH_RF95.cpp> +
-setModemConfig(Bw125Cr45Sf128); +
-</file> +
- +
-In the remainder of this lab, you will conduct measurements to validate the obtained theoretical receiver sensitivity.+
  
 +[{{ :client-iotlab1.png?direct&600 ||Figure 2. Client serial monitor}}]
 +[{{ :server-iotlab1.png?direct&600 ||Figure 3. Server serial monitor}}]
 ===== -. Performance Evaluation ===== ===== -. Performance Evaluation =====
 In the following, you will design and implement a set of scenarios that enable to evaluate the performance of the LoRa modulation. As you will deal with scientific assessment, you are required to use scientific tools to show the results. You have the choice between [[http://www.gnuplot.info | gnuplot]], [[https://matplotlib.org/index.html#|matplotlib]] with Python, and MATLAB. Take some time to become familiar with one of these software as you will be required to use them in different occasions of your academic programme. In the following, you will design and implement a set of scenarios that enable to evaluate the performance of the LoRa modulation. As you will deal with scientific assessment, you are required to use scientific tools to show the results. You have the choice between [[http://www.gnuplot.info | gnuplot]], [[https://matplotlib.org/index.html#|matplotlib]] with Python, and MATLAB. Take some time to become familiar with one of these software as you will be required to use them in different occasions of your academic programme.
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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. 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://www.arduino.cc/en/Reference/Micros| micros()]] function available in the arduino libraries.+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. 
 + 
 +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://www.arduino.cc/en/Reference/Micros| micros()]] function available in the arduino libraries.
  
 <WRAP center round help 100%> <WRAP center round help 100%>
 +  * Join commented extracts of your code and explain your approach for computing the ToA.
   * Draw a box plot of the ToA under the three different radio configurations and for three different message sizes.    * Draw a box plot of the ToA under the three different radio configurations and for three different message sizes. 
-  * Analyze the obtained results and compare with the theoretical computations.+  * Analyze the obtained results and compare with the theoretical computations. You can superpose the theoretical results and the practical ones on the same graph.
 </WRAP> </WRAP>
- +==== -. Packet Delivery Ratio ====
- +
-==== -. Packet Error Rate ====+
  
 In this section, you will measure the Packet Error Rate (PER) under the three different radio configurations and for different transmission periods. For this, you can start by implementing a function on the client that measures the ratio of successfully delivered packets.  In this section, you will measure the Packet Error Rate (PER) under the three different radio configurations and for different transmission periods. For this, you can start by implementing a function on the client that measures the ratio of successfully delivered packets. 
exploring_lora.txt · Last modified: 2021/10/20 12:52 by samer