2016 Volume E99.A Issue 2 Pages 656-659
Nowadays, the batteryless sensor system is widely used for Internet of things (IoT) system. Especially, batteryless backscatter system has a great significance in that it permits us to communicate without power supply devices. However, conventional backscatter system requires high power reader and this can be a problem with the communication efficiency. Therefore, this letter proposes a new transmission scheme on the batteryless backscatter system in order to solve this problem. In the proposed scheme, the mobile devices which embed Wi-Fi chipset are used as a reader. The tag obtains Internet connectivity from the reader. Since the tag can not decode the general Wi-Fi packet, new algorithm of the scheme uses a specially designed packet. In this letter, the designing method for the decodable packet is proposed. Moreover, the scheme implements beamforming to improve the reliability. By concentrating the power to the designated direction, the robust communication can be achieved. The simulation results show that the proposed scheme offers reliable Internet connectivity without extra battery.