Key Technologies Research And Implementation Of Multi-channel Correction

Smart antenna composed of a plurality of antennas is widely used in radar systems, communication systems, et al. Smart antenna is mainly used for DOA(direction of arrival) estimation and DBF(digital beamforming) to enhance anti-interfrence. Besides, mulit-antenna can improve system capacity, such as massive MIMO technology which has become one of the hot research fields in 5G, is an application of smart antenna to improve capacity, and now there exists 128 × 128 MIMO system.When using multi-antenna technology, the consistency of the channels is required. However, in the course of using smart antenna, due to temperature differences in the environment, the aging analog devices, mutual coupling among antennas, and the differences of array element position, et al., there exists amplitude and phase mismatching in multiple channels. So the research of multi-channel smart antenna calibration is very important.Given this, in the paper, multi-channel correction scheme based on spread spectrum calibration sequence is designed, and is verified in the software radio platform. The specific research work is as follows.First of all, multi-channel correction scheme based on spread spectrum sequence is designed. In the design, spread the calibration sequence as training sequence to reduce the influence on useful signal, then add the synchrony sequence. For simulating the correction effect of multi-channel amplitude and phase based on spread spectrum sequence, FIR channel mismatch model is used to verify the scheme, combined with frequency domain correction ways,meanwhile show the MUSIC spectrums. The results show that the amplitude correction error are less than 3%, phase error correction less than 5°.Secondly, the detailed implementation of multi-channel correction scheme is given. The overall architecture of the system is divided into different modules according to the function of the links. Then, the specific implementation process of multi-channel transceiver modules, receiver modules and board interconnect modules is introduced in details, including operating process, data flow analysis, and board interconnect timing analysis. Finally, on this basis, write implementation codes to implement the system links.Thirdly, the performance of multi-channel correction scheme is tested and verified in the software radio platforms, including magnitude errors, phase errors, the performace test of DOA estimation, and the corresponding error analysis. The test results show that the correction design based on multi-channel spreading sequences of the paper meets the system requirements, namely the amplitude correction error is less than 3%, phase error correction less than 5°. The shceme can be applied to the channel correction in smart antenna systems.This paper designs and implements multi-channel correction scheme. The scheme provides a guarantee for the smart antenna accurate of DBF and DOA estimation. The research results can be applied to the next generation of mobile communication network, wireless data link, airborne or carrier communication system, etc, which have important theoretical and economic value.