Abstract: “Receive Signal Strength Indicator (RSSI) is one of performance metrics in wireless communications. The value indicates whether receiver could receive a packet. Since signal can reflex and refract from soil surface, underground nodes may not be able to communicate with aboveground nodes. One way solving this problem is to control the antenna orientation where antenna’s radiation pattern is in an appropriate direction. Therefore, in this work, we develop two types of sensor nodes which are 2-and 3-antenna nodes to improve RSSI values for underground-to-aboveground communications. Results show RSSI values of 2-and 3- antenna have better than those of 1-antenna sensor node approximately 0.85 and 1.43 dBm for manual installation and 2.64 and 6.97 dBm for random installation respectively.”

Keywords: Multiple antennas, Wireless Underground Sensor Networks, Antenna orieantation