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SDR Bridge for a Secure Wireless Sensor Network (WSN)

A software-defined Radio (SDR) is a wireless communication system whose main radio functionalities are implemented in software on an embedded system instead of hardware. The advantages of SDR include its wide range of frequency channels that have configurable bandwidths in addition to its support of multiple configurations and modulations. In this paper, an SDR bridge implemented within a wireless sensor network (WSN) is developed. The SDR bridge is inserted as a gateway between sensor nodes and the end-user receiver to add security to the overall network. For this study, LoRa link is chosen to ensure communication between the network components because of its low power consumption and its long range. Typically, the sensor nodes will send their data to the SDR bridge using LoRa modulation. The bridge will add a layer of security to the overall system by encrypting the signals sent within the bridge. Experimental results found during this study showed that the SDR Bridge allows successful interconnection of the sensor nodes and the end-user receiver. Also, the SDR Bridge prevented reception of the data by the user when data was encrypted unless the proper key was used. Encryption of the signal did not have a significant effect on the QoS since the Packet Loss Ratio (PLR) of the link was around 1.6%. When the bridge is used, the Received Signal Strength Indication (RSSI) was also within the typical values for the LoRa receiver.