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--- exploring_lora [2018/09/27 10:32] – [5. Theoretical Analysis] samer
+++ exploring_lora [2018/09/29 11:40] – [3.1. Modifying the Radio Parameters] samer
@@ Line 8: / Line 8: @@
   * How LoRa is compatible with LPWAN requirements and constraints?
 </WRAP>
-===== -. Hardware Platform =====
+===== -. Setting the Lab =====
+==== -. Hardware Platform ====
 In order to design and implement experiments with LoRa, you will use the following devices:
@@ Line 21: / Line 24: @@
   * Give an estimated cost of your platform.
 </WRAP>
-===== -. Software Tools =====
+==== -. Software Tools ====
 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]].
@@ Line 32: / Line 36: @@
 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>
-===== -. Installation =====
+==== -. Installation ====
 Start by plugging the Dragino shields on the Arduino devices and mounting the antennas as shown in Fig. 1.
@@ Line 45: / Line 49: @@
 For Arduino Mega 2560, additional drivers for Microsoft Windows can be installed from [[http://wch.cn/download/CH341SER_ZIP.html]].
 </WRAP>
-===== -. Running Basic Sketches =====
-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).
-<file cpp RH_RF95.cpp>
+===== -. Theoretical Study =====
-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.
-[{{ :client-iotlab1.png?direct&600 ||Figure 2. Client serial monitor}}]
-[{{ :server-iotlab1.png?direct&600 ||Figure 3. Server serial monitor}}]
-===== -. Theoretical Analysis =====
 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.
@@ Line 67: / Line 61: @@
   * Compare the computed sensitivity to that provided by the {{ :an1200.22.pdf |Semtech Application Note AN1200.22}} for the same parameters.
 </WRAP>
-===== -. Modifying the Radio Parameters =====
+In the remainder of this lab, you will conduct measurements to validate the obtained theoretical receiver sensitivity.
+===== -. Configuring and Running the Lab =====
+==== -. Modifying the Radio Parameters ====
+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.
+Start by setting the central frequency of your LoRa modules according to the following table:
+^  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      |
 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 =====
 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.
 ==== -. 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%>
+  * 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.
-  * 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>
+==== -. 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.
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   * What type of mathematical models enables to theoretically compute the PER?
 </WRAP>
 ==== -. Coverage ====