Low Power Wide Area Networks (lpwan): Technology Review And Experimental Study on Mobility Effect

SYSTEM IMPLEMENTATION

1. SYSTEM ARCHITECTURE

We design a completely functional Symphony Link test platform to conduct experiments for evaluating the performance of LoRaWAN system under various mobility settings. The components selected according to the availability and suitability of this research are :

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  Symphony LoRa module LL-RXR-27
  
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  Symphony gateway LL-BST-8
  
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  Symphony link conductor
  
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  Symphony LoRa evaluation board
  
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  Prelude LoRa evaluation program
  
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  Dell Precision M4400 as host terminal
  

Figure 16: System architecture.
Figure 16 shows the interface of all the components used for conducting experiments in this research. The host terminal being used is the Dell Precision M4400. The host runs a script which would send a fixed number of messages to the end node and also record the response from the gateway for each of the message sent and store these responses in a data file for further analysis. In order to perform functions like firmware upgrade, registration of new end node, communication with the node, Link Labs has designed a GUI application called Prelude which runs on the host terminal. All the functions performed by Prelude can also be performed by using command line functions.
The host terminal connects to the LL module evaluation board via a USB connection. The
Lora Module LL-RXR-27 is attached to the LL Module evaluation board built by Link Labs. This evaluation board has a USB-to-UART bridge which makes it possible to control the LoRa module by using a PC over USB. This feature serves our purpose of controlling the module using a host PC. The LoRa module sends and receives data to and from the LL-BST-8 gateway over the ISM frequency band. The gateway is connected to a cloud based application called the Conductor. The Conductor is responsible for keeping track of LoRa applications, gateways and the end nodes currently being used in the network. It also acts as a database for all the uplink and downlink data send between the end node and the gateway. The details of components shown in Figure 16 are discussed below.

2.