Estimation of Desired power and Undesired power Using Chirp Demodulation and Evaluation of Accuracy

In recent years, Low Power Wide Area (LPWA) has attracted attention for utilizing Internet of Things (IoT). LPWA is a standard of wireless sensor network for wide area coverage and low power consumption. Even in an environment where it is difficult to secure a power source, LPWA can be used for a long time with a battery, so its maintenance cycle can be a large period. The wireless systems including LPWA share the common frequency channel and thus the co-channel interference (CCI) among them is serious problem. Long Range (LoRa), which is one of the standards of LPWA, uses chirp modulation (spread spectrum technology) to suppress CCI. In this modulation method, the resistance to CCI can be strengthened by increasing the spreading factor of the signal, but at the same time, the transmission rate decreases. Therefore, it is necessary to design an appropriate spreading factor that matches the required Signal to Interference Ratio (SIR). In this paper, we propose the estimation scheme for the desired and the undesired power in the LPWA receiver. It is based on LoRa modulation scheme. From the computer simulation, the accuracy of the proposed estimation scheme is evaluated.