Carrier Frequency Offset and Channel Estimation for Passive Backscatter Communication Systems

Backscatter communications, one key key technology for Internet of Things (IoT), attract extensive attentions recently. In one typical backscatter communication system, there may exist carrier frequency offset (CFO) between the receiver and the transmitter, which is often neglected by most studies. The CFO may result from the relative motion of the transceiver, the accuracy of crystal oscillator, and the changes of the physical environment such as the difference of temperature or humidity. CFO seriously affects the signal detection performance at the receiver. Accurate estimation of CFO is of vital significance to improve the system performance. This paper first establishes the backscatter communication system model with CFO, then design an estimator using the least squares method, and next estimates the CFO using a one-dimensional linear search method. Finally, simulation results are provided to corroborate our proposed studies.