Frequency Offset Estimation and Compensation Method Based on Idle Subcarriers in Constant Envelope Orthogonal Frequency Division Multiplexing System

Abstract

The invention discloses a carrier frequency offset estimation and compensation scheme for a constant envelope frequency division multiplexing (OFDM) system using null subcarrier, and belongs to the field of wireless communication. The method comprises the following steps: performing FFT (Fast Fourier Transform) operation on a signal being subjected to phase demodulation at a receiving end to obtain a sequence including an available signal and frequency offset information; estimating the frequency offset by using a feature that the available signal includes the null subcarrier; performing compensation on the signal according to the estimated frequency offset; and performing phase demodulation, FFT, conjugate sequence deconstruction and symbol de-mapping on the signal subjected to the frequency offset compensation to obtain a received bit. Through adoption of the method, the problem of bit error rate increase caused by frequency offset is solved; an extra module does not need to be introduced; the complexity is relatively low; and the influence of the frequency offset on the system performance is effectively restrained.

Description

technical field [0001] The present invention belongs to the field of wireless communication, and specifically refers to a constant envelope orthogonal frequency division multiplexing (CE-OFDM) frequency offset estimation and compensation technology based on idle subcarriers, which is applied to broadband wireless communication. Background technique [0002] In broadband wireless communication systems, information is transmitted in space through modulated electromagnetic waves to the receiver. Due to the complex communication environment, electromagnetic waves are affected by reflection, diffusion, and scattering during space transmission, and multiple received signals with different delays and signal strengths will be generated at the receiver, making the communication channel have time-varying frequency selective fading. characteristic. In order to effectively eliminate the frequency-selective fading of broadband communication channels, multi-carrier modulation technology ...

AI Technical Summary

Problems solved by technology

This method uses the characteristics of CE-OFDM to set idle subcarriers when constructing centrally conjugated symmetric data at the sending end, and the mathematical principle of DFT, estimates and compensates the frequency offset at the receiving end, and solves the problem of increasing the bit error rate caused by frequency offset

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