Differences

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--- exploring_lora [2018/10/08 10:10] – [1.3. Installation] samer
+++ exploring_lora [2018/10/13 09:53] – [4.1. Time on Air] samer
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 Unzip the RadioHead library and copy it to your sketchbook library folder as detailed in [[https://www.arduino.cc/en/Guide/Libraries]].
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+Make sure to restart your computer after the installation of Arduino IDE and run the software as administrator.
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 ==== -. Installation ====
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-For Arduino Mega 2560, additional drivers for Microsoft Windows 8 can be installed from [[http://wch.cn/download/CH341SER_ZIP.html]].
+For Arduino Mega 2560, additional drivers for Microsoft Windows 7 or 8 can be installed from [[http://wch.cn/download/CH341SER_ZIP.html]].
+For Arduino Duemilanove, additional drivers can be installed from
+[[https://www.ftdichip.com/Drivers/CDM/CDM21228_Setup.zip]]
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 ===== -. Theoretical Study =====
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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?
   * How does the spreading factor impact the coverage of a LoRa transmitter?
   * What is the transmission bit rate for each of the following configurations of your LoRa device? Explain your computation.
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 For example, the scenario for assessing the impact of the spreading factor on the ToA consists of sending 100 packets for three different spreading factors //e.g.,// 7, 9, and 10, and drawing the average ToA or the distribution in a boxplot for comparing the results.
+As for the theoretical computation of the ToA, you can refer to the the following documents :
+  * The Semtech [[http://semtech.com/uploads/documents/DS_SX1276-7-8-9_W_APP_V5.pdf| specification]] (section 4.1.1.6)
+  * An explanatory video: https://www.youtube.com/watch?v=C_Rh5GSENA4
+  * Various calculation tools available online: https://www.loratools.nl/#/airtime, [[https://docs.google.com/spreadsheets/d/1voGAtQAjC1qBmaVuP1ApNKs1ekgUjavHuVQIXyYSvNc/edit?usp=sharing |Spreadsheet]]
+Note that all messages sent and received by the [[https://www.airspayce.com/mikem/arduino/RadioHead/classRH__RF95.html| RH_RF95 RadioHead]] driver we are using conform to this packet format:
+  * 8 symbol PREAMBLE
+  * Explicit header with header CRC (handled internally by the radio)
+  * 4 octets HEADER: (TO, FROM, ID, FLAGS)
+  * 0 to 251 octets DATA
+  * CRC (handled internally by the radio)
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