Chang-Bin Ha

Phase adjustment signaling based on packet structure for Wi-Fi backscatter system

This paper proposes the phase adjustment signaling based on packet structure for the Wi-Fi backscatter system. The Wi-Fi backscatter system has very low data rate due to the transmission method by unit of packet. In addition, because the Wi-Fi backscatter system uses simple energy detection method for identification of request information from the reader, the system has very low reliability. In order to solve these problems, the signaling that adjusts transmission power in according to transmitting information is proposed. For improvement of data rate of the system, the proposed signaling uses the transmission method by unit of OFDM symbol in Wi-Fi packet. Also, for improvement of reliability of the system, the proposed signaling uses the iterative transmission method in Wi-Fi packet. The simulations show that the proposed signaling improves performance of the Wi-Fi backscatter system. Also, because the proposed signaling can easily achieve diverse data rate or reliability in according to the parameters, it is useful to meet the demands of IoT application for specific data rate or reliability.

Cooperative Communication for Multi-Hop Routing in ZigBee Network

In this paper, we propose multi-hop routing scheme using RSSI to improve the reliability of ZigBee network. By using RSSI for the routing, the transmitted signal is less affected by the fading in each link on the routing path. If the proposed routing scheme is applied to relaying, the demodulation error is reduced in each relay node and the performance is significantly improved as the number of hops increases. Also, if the proposed scheme is applied to the cooperative communication, the improved diversity gain is additionally obtained.