【作者】 李霞；

【导师】 江桦；

【作者基本信息】 解放军信息工程大学 ， 军事通信学， 2011， 博士

【摘要】 超宽带通信技术具有截获与检测概率低、抗干扰与穿透能力强、系统共存性好、适合高速数据传输以及测距精度高等突出特点,因此在军事和民事领域具有广阔的应用前景。超宽带通信技术目前主要应用于短距离的高速率数据传输等领域,而在国家安全、反恐维稳、交通管理、工业控制等领域对拓展距离超宽带通信技术的应用需求十分旺盛。发送参考超宽带通信技术具有无需复杂信道估计、对定时同步要求低、可以实现多径能量收集以及有利于小型化、低功耗设计等特点,因此成为超宽带通信领域的重要研究内容之一。发送参考超宽带通信系统存在时域、频域和码域三种具体实现结构。本文面向拓展距离超宽带通信的应用需求,在参与提出码域发送参考超宽带通信技术体制的基础上,针对这一新型超宽带通信技术体制进行了进一步研究,主要研究内容与创新点如下:1.从提高系统误码率性能的角度开展研究,提出一种改进型的码域发送参考脉冲超宽带通信接收机结构。本论文给出了改进型接收机的基本结构模型,推导了改进型系统在加性高斯白噪声信道和多径信道条件下的误码率表达式,仿真分析了其误码率性能;同时,针对改进型接收机的同步捕获策略进行研究,推导了改进型接收机在加性高斯白噪声信道和多径信道下的同步捕获参数表达式,仿真分析了改进型接收机的同步捕获性能。研究结果表明,在适当提高接收机复杂度的条件下,通过选取最佳积分区间,改进型接收机不仅可以保持码域发送参考脉冲超宽带通信原型接收机的固有技术优点,而且可以有效提高系统的误码率性能。2.从提高系统信息传输速率的角度开展研究,提出一种码域发送参考脉冲超宽带通信系统的多路并行传输方法。本论文给出了多路并行传输系统的基本结构模型,推导了其在加性高斯白噪声信道和多径信道条件下的误码率表达式,给出了多路并行传输结构的正交码选取方法,仿真分析了多路并行传输系统的误码率性能。研究结果表明,通过参考支路信号能量的复用,这种并行传输方法可以适应较高信息速率传输的要求,并且在中低信噪比条件下每一支路具有优于原型系统的误比特率性能。3.针对系统多用户的应用需求,提出一种码域发送参考脉冲超宽带通信系统的多址接入方法。本论文给出了多址接入系统的基本结构模型,分析了在加性高斯白噪声信道和多径信道下多址干扰对系统误码率性能的影响,仿真分析了多址接入系统的误码率性能。研究结果表明,通过引入一组伪随机跳时码,结合自身的码域发送参考结构,这种多址接入方法可以有效控制多址干扰的影响,并且系统实现复杂度较低。4.从提高系统抗干扰性能的角度开展研究,提出一种码域发送参考Chirp超宽带通信系统的干扰抑制方法。本论文针对码域发送参考Chirp超宽带通信系统的抗干扰性能进行了研究,推导了该接收机在单音干扰和窄带干扰存在条件下信号输出分量和噪声输出分量表达式,仿真分析了该系统的抗干扰性能;在此基础上,结合有源频谱压缩结构,提出一种基于分数阶傅里叶变换的窄带干扰抑制方法,仿真验证了该方法的有效性。研究结果表明,该窄带干扰抑制方法可以有效抑制带内多个随机窄带干扰,具有较强的实用价值。本论文提出的码域发送参考超宽带通信传输与抗干扰方法,目前已在相关课题中得到应用。更多还原

【Abstract】 The Ultra-wideband (UWB) wireless communication system has many advantages such as very low interception and detection probability, excellent anti-interference and material penetration abilities, good performance of system coexistence, high rate data transmission suitability, high precision ranging, and so on, thus making the UWB technology qualified for broad application in military and civil wireless communication. At present, UWB communication technology is mainly used in short distance and high data rate transmission. Meanwhile, there is a strong demand for extending the transmission distance of UWB communication technology in many domains such as national security, antiterrorism and social stabilization, traffic and industrial control, and so on.The impulse radio UWB (IR-UWB) system based on the transmitted reference structure can avoid complicated channel estimation, effectively reduce the demand for synchronization accuracy , collect the energy of multipath, and facilitate miniaturization and low power-consuming system design. Accordingly, IR-UWB system based on the transmitted reference structure becomes an important research direction. Transmitted reference IR-UWB system has three realization structures: time domain, frequency domain, and code domain.Based on the code domain transmitted reference IR-UWB system (the author is one of the designers), the study is followed up in depth in this paper with emphasis on extended distance UWB communication. The main content and innovation are as follows:1. From the point of improving the bit error rate (BER) performance of system, this paper proposes a modified receiver structure of code domain transmitted reference IR-UWB system. The structure model of the receiver is given, and in additive white Gaussian noise (AWGN) and multipath fading (MP) channels, the BER performance expressions are deduced in detail, respectively. The BER performance is also simulated. In addition, this paper studies the synchronization acquisition performance of the modified receiver, and in AWGN and MP channels, the parameter expressions of synchronization acquisition are deduced in detail, respectively. The synchronization acquisition performance is also simulated. The research results indicate that by appropriately increasing the structural complexity of receiver, the modified receiver not only keeps the inherent advantages of the original code domain transmitted reference IR-UWB system receiver, but also achieves improved performance through the selection of optimal integral interval.2. From the point of improving the system information transmission rate, a multiple parallel transmission method of code domain transmitted reference IR-UWB system is proposed. This paper gives the structure model, and the BER performance expressions in AWGN and MP channels are also deduced in detail, respectively. The selection method of orthogonal code is also given. In addition, the performance of the proposed structure is simulated. The research results indicate that by energy multiplexing of reference signal, the multiple parallel transmission structure can not only accommodate to higher transmission rate, but also outperform the original code domain transmitted reference IR-UWB system in error performance for each data signal with middle and low signal niose ratio.3. Aiming at the application requirement of multi users, a multiple access transmission scheme of code domain transmitted reference IR-UWB system is proposed. This paper proposes the structure model, and based on a Gaussian assumption for the multiple access interference, the BER performance expressions in AWGN and MP channels are also derived in detail, respectively. In addition, the performance of the proposed scheme is simulated. The research results indicate that by introducing a pseudo-random time hopping code to the code domain transmitted reference structure to the code domain transmitted reference structure, the scheme can effectively control the influence of multiple access interference. And the system realization complexity is low.4. From the point of improving the system anti-interference performance, an interference suppression method of code domain transmitted reference Chirp-UWB system is proposed. This paper studies the anti-interference performance of the code domain transmitted reference Chirp UWB system. The output signal and noise component expressions of single frequency and narrowband interference of system receiver is deduced, and the anti-interference performance of system is simulated. Furthermore, by combining with the structure of the active spectrum compression, a narrowband interference suppression method based on the fractional Fourier transform is proposed, and its validity is verified through simulation. The research results indicate that the narrowband interference method proposed can effectively suppress the multi random narrowband interference, and is thus of practical value.The extended distance UWB communication transmission and interference suppression methods proposed in this paper has been well used in the relevant projects as a basic technology solution.更多还原