Carrier phase synchronization method and device for non-coherent demodulation circuit

Abstract

The invention discloses a carrier phase synchronization method and device for a non-coherent demodulation circuit. An all-digital implementation mode is adopted for the method and the device, and two working modes, namely. a phase acquisition mode and a phase tracking mode, are adopted. The method comprises the following steps: in a phase acquisition stage in a preamble period, estimating carrier frequency offset by delay-related calculation on a preamble, estimating an initial phase by utilizing a frequency offset estimation result and a known preamble sequence, and performing frequency and phase compensation calculation on received data; after the preamble period, starting dispreading the data, and starting a phase tracking stage; and in the phase tracking stage, performing correlation calculation by utilizing spreading code data corresponding to demodulated symbols and the received data, estimating a residual phase difference of each symbol, and performing phase compensation calculation on the received data. The method and the device are used for the carrier phase synchronization of a non-coherent demodulation digital baseband design, and the carrier phase synchronization can be accurately implemented under the condition of low signal to noise ratio.

Description

technical field [0001] The invention relates to the communication field, in particular to a communication system compatible with the IEEE 802.15.4 standard implemented in a non-coherent demodulation mode, and the invention is used to realize carrier phase synchronization of received signals. Background technique [0002] The IEEE 802.15.4 standard defines two specifications of the physical layer and media access control layer of the low-speed wireless personal area network (LR-WPAN). The characteristics of IEEE 802.15.4 low rate, low power consumption and short distance transmission make it suitable for application in the field of wireless sensor network. The IEEE 802.15.4c physical layer specifies three frequency bands, namely 2.4GHz frequency band, 868 / 915MHz frequency band and 780MHz frequency band. In the 780MHz frequency band dedicated to China, the specification stipulates two physical layer modulation schemes: using O-QPSK modulation scheme and direct sequence spread...

AI Technical Summary

Problems solved by technology

[0005] In the all-digital design scheme, the carrier frequency offset estimation is mostly performed by using the received data to perform delay correlation calculation to complete the frequency offset estimation. If the signal-to-noise ratio is low, the accuracy of the frequency offset estimation will decrease. Seriously deteriorated, because it does not use the relevant information of the known preamble sequence to reduce noise interference, and its phase compensation is only for frequency offset phase compensation, generally does not consider the initial phase estimation and phase residual error tracking, so due to the existence of Frequency estimation error, as the packet length increases, the phase difference of the received data points will accumulate to a large value, which will cause a large bit error rate to the demodulation circuit

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