Short-wave communication frequency offset estimation method based on maximum likelihood

Abstract

The invention discloses a short-wave communication frequency offset estimation method based on maximum likelihood, and the method comprises the following specific steps that a transmitting end transmits the data to be transmitted of a user, wherein the data to be transmitted of the user and a synchronization sequence at the front end form a data frame structure; the digital up-conversion processing is carried out on the data frame structure to obtain a transmitting data sequence; the transmitted data sequence is transmitted through a short wave channel and synchronously sampled, and a received data sequence is obtained at a receiving end; and the frequency offset estimation is carried out on the received data sequence by adopting a maximum likelihood criterion to obtain a frequency offset estimation value of the received data sequence. According to the invention, the problems of rotation of a signal phase, non-correctable errors, sharp deterioration of system performance and the like caused by the larger errors are solved; the channel estimation is not needed while the estimation precision is improved, the calculation complexity is greatly reduced, and meanwhile, the frequent change of the frequency of the receiver crystal oscillator is avoided, and the equipment cost does not need to be increased.

Description

Technical field [0001] The invention belongs to the technical field of shortwave communication, and in particular relates to a method for estimating frequency offset of shortwave communication based on maximum likelihood. Background technique [0002] Shortwave communication refers to a radio communication technology with a wavelength between 100 meters and 10 meters and a frequency range of 3 MHz to 30 MHz. The radio waves emitted by short-wave communication can only reach the receiving end through the reflection of the ionosphere. The communication distance is relatively long, and it is the main means of long-distance communication. Despite the continuous emergence of new radio communication systems, shortwave communication, an ancient and traditional communication method, is still widely valued by the world. Not only has it not been eliminated, but it is still developing rapidly, because it has advantages that other communication systems do not have: First of all , Shortwave ...

AI Technical Summary

Problems solved by technology

[0005] In order to solve the above-mentioned problems, the purpose of the present invention is to propose a method for estimating the frequency offset of short-wave communication based on maximum likelihood, which solves the problems such as the rotation of the signal phase caused by large errors, the generation of uncorrectable errors, and the sharp deterioration of system performance; While improving the estimation accuracy, there is no need for channel estimation, which greatly reduces the computational complexity; at the same time, it avoids frequent changes to the crystal oscillator frequency of the receiver, and does not need to increase equipment costs

Images