高速MIMO-OFDM SOC非理想效应联合自校准和补偿机制研究

With the development and requirement of multi-antenna and high-order modulated wideband high-speed MIMO-OFDM SOC,various impairments are expected to take place in the radio transceivers,especially in the radio-frequency(RF) analog electronics,and it becomes the key problem of restricting the improvement of performance. How to reduce the effects of impairments effectively is the key factor and interesting topic of the high-order antenna(4~8), high-order modulation(64QAM/256QAM) and high-speed MIMO-OFDM communication system(4G/802.11n/ac). The project aims at research on the key technologies of calibration and compensation of impairments for the high-speed MIMO-OFDM SOC. The contents of research include: using RF loopback and baseband digital technologies for joint calibration, research the high-precision, low-complexity and auto-operation calibration mechanism of I/Q mismatch in the coexistence of impairments; using analog and digital technology for joint compensation, research the high-precision and low-complexity compensation mechanism of DC offset in the coexistence of impairments. Establishing the platform of 4 transmitter and 4 receiver high-speed MIMO-OFDM system according to 802.11n/ac, carry on algorithm evaluation, verification on FPGA prototype system and mixed-signal SOC. Achievements of the project are expected to provide exploration, reference and promotion for the research on joint RF, analog and digital calibration and compensation in broadband wireless communication SOC.

随着多天线、高阶调制、高带宽高速MIMO-OFDM SOC发展和应用需求，射频模拟器件引入的非理想效应成为制约性能提升的关键性问题。如何有效减小非理想效应影响是高阶天线(4~8)、高阶调制(64QAM/256QAM)的高速MIMO-OFDM通信系统(4G/802.11n/ac)的关键因素和研究热点。项目拟对高速MIMO-OFDM SOC非理想效应校准和补偿关键技术进行研究。采用射频环路反馈和基带数字联合校准方法，研究非理想效应共存下高精度、低复杂度和自启动的I/Q失衡校准机制；采用模拟和数字联合补偿方法，研究非理想效应共存下高精度、低复杂度的直流失调补偿机制。根据802.11n/ac协议，建立4发4收高速MIMO-OFDM系统，进行算法评估、FPGA原型系统验证和数模混合SOC验证。项目成果可望对宽带无线通信SOC中涉及射频、模拟及数字交互的联合校准和补偿研究起到良好探索、借鉴和推动作用。

本项目针对面向Gbps MIMO-OFDM系统中非理想效应校准和补偿关键技术进行研究。紧跟国际上超高速无线通信系统与射频芯片技术的研究前沿，设计实现面向IEEE 802.11ac/ad通信标准的射频前端系统芯片，采用射频环路反馈和基带数字技术联合校准方法，研究高精度、低复杂度和上电自运行的I/Q失衡校准与直流失调补偿机制；并考虑多种非理想效应的共存及相互影响，研究共存下的联合补偿机制。解决了Gbps宽带无线通信系统射频前端芯片关键设计问题，以及对非理想效应校准和补偿关键问题，对未来Gbps宽带无线通信系统的应用，起到了良好的探索、借鉴、推动作用。