重叠复用原理在通信中的应用

发布时间：2018-02-20 14:52

  本文关键词： 重叠复用 OvTDM 波形编码 级联OvTDM 迭代检测　出处：《北京邮电大学》2014年博士论文　论文类型：学位论文

【摘要】：重叠复用原理是通信系统最本质的现象。利用重叠复用原理,不仅可以实现高频谱效率传输,还能够获得远优于奈奎斯特系统的性能。重叠时分复用(OvTDM)系统是对重叠复用原理最直接的应用,该技术利用传输数据符号之间的移位重叠,通过在相邻符号之间人为引入ISI的方式提高系统频谱效率。论文主要从理论和实现两个方面对OvTDM进行了分析和仿真验证。 理论方面在第三章详细分析了时域重叠复用系统的频谱效率、功率谱特性、信道容量和差错概率。证明了相邻符号之间的移位重叠不仅不会扩展系统带宽,而且相比于奈奎斯特传输系统不存在过剩带宽的问题,因此可以提高系统频谱效率。OvTDM的实质是一个并行传输系统,因此相比于奈奎斯特系统可以成倍的提高系统的频谱效率。与相同谱效率下的正交传输系统(例如PSK和QAM)传输相比,OvTDM编码输出信号电平数仅随着频谱效率线性增加,而正交调制的信号电平数则是随着频谱效率指数式增加。所以,相同频谱效率条件下OvTDM系统具有更低的峰平比和更大的信号节点欧式距离。信道容量方面证明了OvTDM系统可以达到波形信道的容量,而且严格优于奈奎斯特系统的信道容量。证明了OvTDM系统是一种真正意义上的波形编码方案。 差错概率方面,将ISI信道的差错概率性能界应用到OvTDM系统,得到了OvTDM系统采用矩形复用波形的差错概率。与正交调制相比,OvTDM在差错概率方面有两大优势,一方面OvTDM可以提供较高的编码增益；另一方面相同频谱效率下OvTDM所需的星座点比较少,因此具有较大的星座点距离。 第四章为了提高OvTDM编码在低频谱效率区域的性能,给出了OvTDM的级联模型及其迭代检测算法。由于OvTDM可以等效为一个复数域的卷积编码模型,因此,OvTDM也具有类似于卷积码的不同结构。文中分别给出了三种不同的级联方案：并行级联OvTDM、串行级联OvTDM以及混合级联OvTDM系统。三种结构分别在OvTDM编码之间以及OvTDM和信道编码之间进行了级联。由仿真结果可以看出,级联结构可以有效的增加OvTDM的编码约束长度,从而显著提升OvTDM的系统性能。 多载波OvTDM解决了OvTDM的宽带传输问题。若直接将OvTDM应用到OFDM系统,除了自身的ISI,还会引入子载波间干扰,破坏子载波间的正交性,大大增加了接收机的复杂度。为了克服这个问题,文中构造了一种旋转正交互补码对偶。利用旋转正交互补码对偶实现了多载波OvTDM的传输。从而使得各路OvTDM可以独立译码,该方案在不增加OvTDM检测复杂度的基础上实现了各子载波间的独立传输。 最后给出了OvTDM的多小区组网方案和多用户传输系统。首先利用四色原理给出了OvTDM的四色组网方案,利用该方案,实现了相邻小区间的无干扰传输。而对于多用户的OvTDM传输问题,文中首先给出了多用户OvTDM的矩阵卷积模型。给出了一种和多用户数成线性关系的并行迭代多用户检测算法。该算法不仅算法复杂度低,而且能够快速收敛到最优算法性能。
[Abstract]:Overlapping multiplexing principle is the most essential communication system phenomenon. By overlapping multiplexing principle, can not only realize the transmission of high frequency spectrum efficiency, but also be able to obtain better performance than the Nyquist system. Overlapped time division multiplexing (OvTDM) system is the most direct application of overlapped multiplexing principle, the shift between the transmission of data symbols overlap using the technology, improve the system the spectral efficiency between adjacent symbols artificially introduced ISI. The main realization from the theory and the two aspects of the analysis and Simulation of OvTDM.
The theory in the third chapter detailed analysis of the spectral efficiency of time-domain overlapped multiplexing system, power spectrum, channel capacity and error probability. It is proved that the displacement between adjacent symbols overlap will not only extend the system bandwidth, but compared to the Nyquist transmission system does not have the excess bandwidth, so it can improve the spectrum efficiency of the.OvTDM is the essence of the system a parallel transmission system, so compared to the Nyquist system can improve the spectrum efficiency of the system. With the same spectral efficiency under the orthogonal transmission system (such as PSK and QAM) compared with OvTDM transmission, encoding the output signal level only with the spectral efficiency of linear increase, while the number of quadrature modulation signal level is with spectral efficiency index to increase the peak level. So, OvTDM system under the condition of the same spectral efficiency is lower than and greater signal node Euclidean distance. The channel capacity In terms of volume, it is proved that the OvTDM system can achieve the capacity of the waveform channel, and it is superior to the Nyquist system's channel capacity. It is proved that the OvTDM system is a true waveform coding scheme.
The error probability, ISI channel error probability performance bound is applied to the OvTDM system, the error probability of OvTDM system using rectangular waveform multiplexing. Compared with orthogonal modulation, OvTDM has two major advantages in the error probability, on the one hand, OvTDM can provide high encoding gain; on the other hand, the constellation points the same spectral efficiency under OvTDM the required is relatively small, so it has the constellation points greater distance.
The fourth chapter in order to improve the performance of OvTDM encoding spectral efficiency in the low-frequency region, given the cascade model and iterative detection algorithm OvTDM. Because OvTDM convolutional encoding model, equivalent to a complex domain so that OvTDM has a different structure similar to convolutional codes. This paper respectively presents three different schemes of cascade parallel concatenated OvTDM, serial concatenated OvTDM and hybrid cascade OvTDM system. Three structures were between OvTDM and between OvTDM encoding and channel encoding of the cascade. The simulation results show that the cascade structure can effectively increase the OvTDM encoding constraint length, thus greatly improve the system performance of OvTDM.
Multi carrier broadband transmission OvTDM solves the problems of OvTDM. If the OvTDM is applied to the OFDM system, in addition to their own ISI, will introduce intercarrier interference, destroy the orthogonality between subcarriers, greatly increasing the complexity of the receiver. In order to overcome this problem, this paper constructs a dual rotating orthogonal code by rotating orthogonal code to achieve dual transmission of multi carrier OvTDM. So that each OvTDM can be independently decoded, the scheme on the basis of not increasing the complexity of OvTDM detection based on the independent transmission of each sub carrier.
Finally, the multi cell network scheme OvTDM and multi-user transmission system are given. The first principle is given four four-color networking scheme of OvTDM by using this scheme, the interference free transmission between adjacent cells. The OvTDM transmission problem of multiple users, this paper gives a matrix convolution model of multi user OvTDM is given. A multi user and a linear relationship between the number of parallel iterative multiuser detection algorithm. The algorithm not only the complexity of the algorithm is low, and can quickly converge to the optimal performance of the algorithm.

【学位授予单位】：北京邮电大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TN911.2

【参考文献】

相关期刊论文 前3条

1 杨星;李道本;邹永忠;李宗霖;;一类新的LS码及其构造方法[J];北京邮电大学学报;2006年03期

2 李道本;传统CDMA与LAS-CDMA中的重要关系及比较[J];电信科学;2002年10期

3 刘兵朝;李道本;;一种正交时频码及其应用[J];北京邮电大学学报;2013年05期

，

本文编号：1519236