基于压缩感知的多点协作技术研究

发布时间：2018-04-22 13:45

本文选题：多点协作联合传输 + 预编码　；参考：《福州大学》2014年硕士论文

【摘要】：多点协作技术(Coordinated Multi-Point, CoMP)是先进的长期演进(Long Term Evolution Advanced, LTE-A)提高小区边缘用户吞吐量和网络整体数据传输速率的核心技术。CoMP的联合处理方式以预编码技术为基础,其解码过程要求协作基站的信号同时到达用户终端。实际网路中,用户位置分布具有一定的随机性和移动性,协作基站难以根据有限的反馈信息保证信号能同时或者以较少的时延差到达用户终端,这就产生了多用户协作的异步干扰问题。目前研究学者主要通过设计有限反馈信道的预编码方法消除异步干扰,但这些预编码方法复杂度普遍较高。本文以先进的压缩感知技术为基础,通过合理设计低速率的压缩采样方案,提取感兴趣信号,有效地消除异步干扰。本文首先介绍CoMP的联合处理技术,构建结合中继和CoMP技术的异构网络模型,分析异构通信网络模型的异步干扰问题。异步干扰是到达用户端的协作基站信号之间的时延差而引起的,在傅里叶变换解调后会造成LTE-A信号的子载波间干扰。相关文献已经证明利用部分傅里叶变换可以有效消除子载波间干扰对系统的影响。本文根据现有文献的设计思想,将快速傅里叶采样方法从离散时间域扩展到连续时间域中,提出了以随机部分傅里叶变换为基础的压缩感知异步干扰抵消方法。该方法首先通过多通道的模拟信息转换器,实现LTE-A信号频谱的随机循环移位,然后通过滤波器组提取感兴趣信号,分解信号的重要频谱,以sub-Nyquist速率采集信息,并对采集的离散信号样本进行部分傅里叶变换,估计包含重要信息的频率和相应的系数。本文采用的压缩感知算法以部分傅里叶变换为核心,只提取子载波的主频信息,可以有效地消除异步干扰的影响。仿真实验证明连续时间域傅里叶采样系统能以sub-Nyquist速率接收LTE-A信号的同时有效地消除异步干扰对系统性能的影响。在信号的带宽为10MHz,载频为2GHz情况下,根据香农定理,接收系统的奈奎斯特采样率为4.01GHz。本文提出的连续时间域傅里叶采样接收系统可以在信号未受到异步干扰的情况下,以1.296GHz的系统采样率达到传统的奈奎斯特速率采样信号再通过傅里叶变换解调的相当性能。在接收信号受到异步干扰的影响下,传统的信号接收方法性能急剧下降,而本文提出的连续时间域傅里叶采样系统可以在采样率为1.296GHz,信噪比为30dB条件下,误比特率下降到10-4以下。
[Abstract]:Co-coordinated Multi-Point.comp is the core technology of advanced long term evolution long Term Evolution Advanced (LTE-A) to improve cell edge user throughput and overall data transmission rate of network. The combined processing method of comp is based on precoding technology. The decoding process requires the signal of the cooperative base station to arrive at the user terminal at the same time. In the actual network, the user location distribution has some randomness and mobility, so it is difficult for the cooperative base station to ensure that the signal can reach the user terminal at the same time or with less delay difference according to the limited feedback information. This leads to the asynchronous interference problem of multi-user cooperation. At present, researchers mainly design precoding methods for limited feedback channels to eliminate asynchronous interference, but the complexity of these precoding methods is generally high. Based on the advanced compression sensing technology, this paper, by reasonably designing the low rate compression sampling scheme, extracts the interested signal and effectively eliminates the asynchronous interference. This paper first introduces the joint processing technology of CoMP, constructs the heterogeneous network model combining relay and CoMP technology, and analyzes the asynchronous interference problem of the heterogeneous communication network model. The asynchronous interference is caused by the delay difference between the signals of the cooperative base station which arrives at the client. After the Fourier transform demodulation, it will cause the inter-carrier interference of the LTE-A signal. It has been proved that partial Fourier transform can effectively eliminate the influence of inter-carrier interference on the system. In this paper, based on the design ideas of existing literature, the fast Fourier sampling method is extended from discrete time domain to continuous time domain, and a compression sensing asynchronous interference cancellation method based on random partial Fourier transform is proposed. In this method, the random cyclic shift of LTE-A signal spectrum is realized by a multi-channel analog information converter, and then the signal of interest is extracted by filter bank, the important spectrum of signal is decomposed, and the information is collected at sub-Nyquist rate. The frequency and coefficient of important information are estimated by partial Fourier transform. The compression sensing algorithm adopted in this paper is based on partial Fourier transform and only extracts the main frequency information of subcarriers, which can effectively eliminate the influence of asynchronous interference. The simulation results show that the continuous time domain Fourier sampling system can effectively eliminate the influence of asynchronous interference on the system performance while receiving LTE-A signals at sub-Nyquist rate. Under the condition that the signal bandwidth is 10MHz and the carrier frequency is 2GHz, according to Shannon's theorem, the Nyquist sampling rate of the receiving system is 4.01 GHz. The proposed continuous time domain Fourier sampling and receiving system can achieve the equivalent performance of conventional Nyquist rate sampling signal and demodulating by Fourier transform with the system sampling rate of 1.296GHz without asynchronous interference. Under the influence of asynchronous interference on the received signal, the performance of the traditional signal receiving method drops sharply. However, the proposed continuous time domain Fourier sampling system can be used at a sampling rate of 1.296 GHz and a signal-to-noise ratio of 30dB. The bit error rate drops below 10-4.
【学位授予单位】：福州大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.5

【相似文献】