exploring_lora
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exploring_lora [2018/09/29 15:39] – [4.3. Coverage] samer | exploring_lora [2018/10/06 13:45] – [1.2. Software Tools] samer | ||
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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: | ||
- | * Arduino Mega (x2). | + | * Arduino Mega or Arduino Duemilanove |
* LoRa shields from [[http:// | * LoRa shields from [[http:// | ||
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* Give the main characteristics of the LoRa shield from Dragino (www.dragino.com). | * Give the main characteristics of the LoRa shield from Dragino (www.dragino.com). | ||
* What type of Antenna are you using? Explain the corresponding characteristics. | * What type of Antenna are you using? Explain the corresponding characteristics. | ||
- | * Give an estimated cost of your platform. | + | * Give an estimated cost of your devices. |
</ | </ | ||
- | |||
==== -. Software Tools ==== | ==== -. Software Tools ==== | ||
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Unzip the RadioHead library and copy it to your sketchbook library folder as detailed in [[https:// | Unzip the RadioHead library and copy it to your sketchbook library folder as detailed in [[https:// | ||
- | |||
- | <WRAP center round tip 75%> | ||
- | 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. | ||
- | </ | ||
==== -. Installation ==== | ==== -. Installation ==== | ||
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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 | + | * What is the transmission bit rate for each of the following |
+ | * Configuration 1: channel bandwidth = 125 kHz, spreading factor = 7, coding rate = 4/5 | ||
+ | * Configuration 2: channel bandwidth = 500 kHz, spreading factor = 7, coding rate = 4/5 | ||
+ | * Configuration 3: channel bandwidth = 125 kHz, spreading factor = 12, coding rate = 1/2 | ||
* 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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Download the {{ : | Download the {{ : | ||
- | Take a look at the source code in '' | + | Take a look at the source code in '' |
- | * Central frequency | + | * Central frequency |
- | * Spreading Factor | + | * Spreading Factor |
- | * Bandwidth | + | * Bandwidth |
- | * Coding Rate (CR) | + | * Coding Rate |
- | * Transmit power (Pow) | + | * Transmit power |
<code c++> | <code c++> | ||
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==== -. Time on Air ==== | ==== -. Time on Air ==== | ||
- | In this section, you will measure the Time on Air (ToA) as given by the time necessary to transmit a message on the radio interface. You will assess the impact of the spreading factor, bandwidth, coding rate, and the message size on the ToA. | + | In this section, you will measure the Time on Air (ToA) that is given by the time necessary to transmit a message on the radio interface. You will assess the impact of the spreading factor, bandwidth, coding rate, and message size on the ToA. |
- | For this, you will start by implementing a function on the client that measures the time necessary for sending a message. For example, you can use the [[https:// | + | 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%> | ||
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* Analyze the obtained results and compare with the theoretical computations. You can superpose the theoretical results and the experimental ones on the same graph. | * Analyze the obtained results and compare with the theoretical computations. You can superpose the theoretical results and the experimental ones on the same graph. | ||
</ | </ | ||
+ | ==== -. Coverage ==== | ||
- | ==== -. [Classroom activity] Collisions and Packet Delivery Ratio ==== | + | In this section, you will measure the coverage of LoRa under different radio configurations. |
- | In this section, you will measure the Packet Delivery Ratio (PDR) under different transmission periods. Only for this test, all groups are required | + | Start by identifying a set of five geographical locations or Test Points |
- | + | ||
- | You will start by implementing | + | |
- | + | ||
<WRAP center round help 100%> | <WRAP center round help 100%> | ||
- | * Draw the PER as a function | + | * Draw the test points on a map and motivate your choices. |
- | * What type of mathematical models enables to theoretically compute | + | * Describe the radio configurations you selected and their impact on the reliability |
+ | * Visualise | ||
+ | * Analyze | ||
</ | </ | ||
+ | ==== -. [Classroom activity] Collisions and Packet Delivery Ratio ==== | ||
- | ==== -. Coverage ==== | + | In this section, you will measure the impact of the packet arrival rate on the collision rate and consequently the PDR. |
- | In this section, you will measure the coverage of LoRa under the three different radio configurations. Such configurations should ensure different reliability levels. | + | The setting for this experiment is unique: |
- | For this, you will start by identifying a set of geographical locations or Test Points (TP). These TPs should be astutely chosen to challenge | + | * Only one server is required in the classroom. This server |
+ | * All groups are required to use the same frequency, spreading factor, and coding rate. | ||
+ | * On each client, packets will be generated following a Poisson process with the same average arrival rate for all groups. | ||
<WRAP center round help 100%> | <WRAP center round help 100%> | ||
- | * Draw the test points on a map. | + | * Draw the PDR as a function of the average arrival rate. Analyze your results. |
- | * Give a statistical measure | + | * What type of mathematical model enables to theoretically compute |
</ | </ | ||
- | ==== -. Path Loss ==== | + | ===== -. Coverage Challenge ===== |
- | In this section, you will study the properties | + | In this section, you are required to establish a record |
+ | |||
+ | * Direct transmission between | ||
+ | * 3D distance is computed between devices. | ||
+ | * PDR must be higher than 10% as computed | ||
<WRAP center round help 100%> | <WRAP center round help 100%> | ||
- | * Provide | + | * Compute |
- | * Draw the RSSI values as a function | + | * Provide |
- | * What is the path loss exponent? | + | * Compare the received power obtained |
- | * Using regressions, | + | * Write an article (blog, wiki, ...) to describe your experiment. |
- | * Compare the obtained | + | |
</ | </ | ||
- | |||
- | In order to compute distances in your experiment, you can get the GPS coordinates as recorded by your smartphone using an application such as [[https:// | ||
- | ===== -. Coverage Challenge ===== | ||
- | |||
- | |||
===== -. Grading ===== | ===== -. Grading ===== | ||
exploring_lora.txt · Last modified: 2021/10/20 12:52 by samer