Carrier Frequency Synchronization in Distributed Wireless Sensor Networks

Abstract

Carrier frequency synchronization is a difficult problem in distributed wireless sensor networks (WSNs) due to its high-precision requirement. In this paper, we propose simple and easily implementable carrier frequency synchronization for distributed WSNs with a master-slave structure. The slave sensors receive the calibration signal broadcasted from the master sensor (base station) and modulate them in a novel manner such that the retransmitted signal can be easily extracted by the master sensor to compensate the carrier frequency synchronization errors. The advantage of this method is that it does not require a priori establishment of the time synchronization between the master sensor and slave sensors and that no additional resource would be required to transmit as synchronization signal. Moreover, the impact of Doppler frequency shift is canceled to some degree in this approach. We present the carrier synchronization compensation algorithm and discuss several practical implementation issues. We also derive the stochastic Cramér-Rao lower bound performance analysis of the method and provide numerical results that validate the analysis.

Distributed Radio Frequency Cooperation at the Wavelength Level Using Wireless Phase Synchronization

“…In wireless sensing, closed-loop architectures were implemented for frequency synchronization [20]. Open-loop architectures were also implemented such as in [21], but these approaches are slow and require significant processing. Coupled-oscillators [22] and optically-locked voltage controlled oscillators [23] were implemented for wireless frequency synchronization, however the performance of such systems highly depends on the separation distance, and in the case that obstacles are present in between the transmitter and receiver, frequency synchronization might not be possible.…”

Effect Analysis of Time and Carrier Frequency Offset on the Performance of Distributed Transmit Beamforming for Emergency Radio

“…As for performance analysis, we adopt the PDF assumption in [3] and [14]. ∆ f i is treated as a random variable, and its mean and standard deviation of CFO are shown below:…”

Precise frequency synchronization detection method based on the group quantization stepping law

“…The commonly used frequency measurement methods include the direct counting method, multi-period synchronization method, analog interpolation method, and time Vernier method [10–11]. The direct counting method and the multi-period synchronous method have a ±1−word counting error [12–13]. Since the frequency of the filling signal is generally less than 10 9 Hz, the accuracy of the frequency measurement is usually lower than 10 −9 /s.…”