A Query Strategy of Mobile Node under LoRa Wireless Network with Relay Mechanism

• Main Authors: CHANG,TSUNG-KAI, 張琮凱
• Other Authors: LEE,HUANG-CHEN
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/63ud9z

碩士 === 國立中正大學 === 通訊工程研究所 === 106 === The Internet of Things (IoTs) is envisioned to connect all smart devices to the network, for exchanging data and assist our daily life cooperatively. Many IoT mobile devices such as networked vehicles and people with wearable devices have been developed to provide intelligent services. However, the mobility of devices causes various issues, which increase the difficultly to maintain a good communication quality between mobile device and its gateway, including the mobile node's moving speed, direction and location. Many IoT wireless communication technologies, such as Bluetooth, WiFi, ZigBee and LoRa, are aimed to facilitate the IoT services. Recently, LoRa has been proposed to provide long-distance communication, while LoRaWAN is a protocol standard based on a star-topology wireless network for offering IoT device to connect to LoRa network. As the nature of radio signals can be degraded and interfered by increasing travel distance, obstacles and other radio sources, using relay nodes can help to increase the communication range and provide better quality of service. This study discusses how to maintain the communication performance of mobile LoRa nodes in a campus-scale star-topology LoRa wireless network with relay mechanism. The major difficulty of this architecture is how to select a proper relay node for a moving mobile node to provide good communication quality. Meanwhile, different query strategies of select relay node and query sequence are analyzed in simulations and real experiments. As the results indicated, the query success rate from a gateway to a mobile node via relays is raised to 67% with the proposed strategy, while the success rate is only 34% if no strategy is used.