A GPS Synchronized, Long-Range Uplink-Only Radio Designed for IoT

Abstract

Targeting IoT, we have developed an efficient radio system. The system uses GPS (Global Positioning System) for time and frequency calibration. The system uses a newly designed LDPC as error correction, an efficient pi/2 shift BPSK modulation and linear chirp modulation for spectrum spreading. In this system, the transmission channel is estimated using evenly-distributed sync symbols and the channel deterioration is corrected. Together with these technologies, we have experimentally confirmed that the system exhibits -144 dBm of sensitivity. We also confirmed that it could achieve long-range communication in an urban environment. Another experiment shows that signals from a fast moving object can also be decoded.