同时同频全双工数字自干扰抑制关键技术

发布时间：2018-05-20 21:07

本文选题：同时同频全双工 + 数字自干扰抑制　；参考：《电子科技大学》2016年博士论文

【摘要】：同时同频全双工在相同时间使用相同频率发送接收信号,相对传统的时分双工和频分双工,最高能获得两倍的频谱利用率,是提高下一代无线通信系统容量的有效措施之一。实现同时同频全双工需要解决同频自干扰的问题,目前普遍采用的是天线抑制、射频抑制和数字抑制联合的自干扰抑制方案。数字抑制作为最后一道抑制手段,其残留的自干扰将会作为最终残留自干扰,所以对最终抑制效果的影响非常重要。本文聚焦于高性能、低成本的数字自干扰抑制技术研究,具体贡献包括:第一,给出数字自干扰抑制下干信比与ADC位数影响误符号率的闭式解。通过分析数字自干扰抑制下干信比与ADC位数对实际判决门限的影响,推导得出QAM调制系统误符号率表达式,从而可为工程上设定模拟自干扰抑制指标限制干信比和选择ADC位数提供依据。在16-QAM调制,比特信噪比14dB,干信比不大于40dB时,只需12位ADC即可能达到接近510-的极限误符号率。第二,提出一种反馈辅助精确测量非线性自干扰的抑制方案。首先通过分析抑制能力,证明反馈方案由于获知了发射通道非线性因而优于非反馈方案。在相位噪声方差为0.0075rad2,反馈与接收通道时延误差为30ns时,反馈方案比非反馈方案的抑制能力高27dB。然后提出一种去除反馈中占主导地位的线性分量并精确测量非线性分量的自干扰抑制方案,在不损失抑制性能的前提下降低对反馈通道ADC位数的需求,从而降低成本。在原反馈通道使用12位ADC接收包含线性与非线性分量自干扰的情况下,本方案只需使用8位ADC接收自干扰非线性分量。第三,提出一种可用于单天线全双工系统的数字预处理自干扰抑制技术。所提技术通过在发射基带引入数字预消除信号,消除时延较大的自干扰径,达到抑制自干扰的效果。当幅值误差在5%范围内时,其对目标径的抑制能力大于20dB。第四,提出一种补偿串扰的全双工MIMO数字自干扰抑制方案。在发射通道存在串扰与非线性失真情况下,通过发射前补偿串扰与数字预失真,抑制自干扰中非线性分量,使得数字自干扰抑制仅需进行线性重建,降低复杂度。对于20MHz带宽的LTE全双工2×2 MIMO,该方案的数字抑制提供了35dB的抑制能力。论文在同时同频全双工数字自干扰抑制方面的研究成果,可以作为全双工收发器系统方案设计、ADC选型、数字自干扰抑制算法设计等方面的重要参考。
[Abstract]:At the same time, the same frequency full duplex uses the same frequency to send the receiving signal at the same time. Compared with the traditional time division duplex and frequency division duplex, the maximum frequency spectrum utilization can be obtained up to two times. It is one of the effective measures to improve the capacity of the next generation wireless communication system. It is a self interference suppression scheme for antenna suppression, radio frequency suppression and digital suppression. Digital suppression is the final means of suppression, and its residual self interference will be the final residual self interference, so it is very important for the final suppression effect. This paper focuses on the research of high energy, low cost digital self interference suppression technology. The specific contributions include: first, a closed solution of the error rate of the dry signal ratio and the ADC digit of the digital self interference suppression is given. By analyzing the influence of the dry signal ratio and the ADC digit on the actual decision threshold under the digital self interference suppression, the expression of the missymbol rate of the QAM modulation system is derived, thus the simulated self interference suppression index can be set for the engineering. It provides a basis for limiting the ratio of the dry signal to the ADC digits. In the 16-QAM modulation, the bit signal to noise ratio 14dB and the dry signal ratio are not more than 40dB, only 12 bit ADC is required to reach the extreme missymbol rate near 510-. Second, a feedback aided method for accurate measurement of nonlinear self interference is proposed. First, the feedback scheme is proved by the analysis of the inhibition ability. When the phase noise variance is 0.0075rad2 and the delay difference of the feedback and receiving channel is 30ns, the feedback scheme is higher than the non feedback scheme 27dB., and then proposes a linear component that removes the dominant feedback in the feedback and accurately measures the self interference of the nonlinear component. The suppression scheme reduces the demand for the ADC digit of the feedback channel without loss of performance, thus reducing the cost. In the case of the original feedback channel using 12 bit ADC receiving the self interference of linear and nonlinear components, the scheme only needs 8 bit ADC to receive self interfering non linear components. Third, a kind of single antenna is proposed to be used as a single antenna. The technique of digital preprocessing self interference suppression in duplex system. The proposed technique can suppress self interference by introducing digital precanceling signals in the transmitting baseband to eliminate the effect of self interference. When the amplitude error is within the range of 5%, the ability to suppress the target diameter is greater than 20dB. fourth, and proposes a full duplex MIMO for compensating crosstalk. Digital self interference suppression scheme. In the case of crosstalk and nonlinear distortion in the transmission channel, by compensating crosstalk and digital predistortion before transmission, the nonlinear component is suppressed in self interference, which makes the digital self interference suppression only needs linear reconstruction and reduces the complexity. For the 20MHz band wide LTE full duplex 2 x 2 MIMO, the digital suppression of the scheme The research results of the same frequency full duplex digital self interference suppression in the same frequency can be used as an important reference for the design of the full duplex transceiver system, the selection of ADC and the design of the digital self interference suppression algorithm in the whole duplex transceiver system at the same time.
【学位授予单位】：电子科技大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN929.5

【相似文献】