摘要在MIMO通信系统中，以现代密码学为基础的保密手段，已经无法满足现代无线通信技术的发展的安全需求。论文设计了一种通过通信信道特征来实现指定用户接入的算法。该算法可选择指定接入用户，源节点通过随机正交的信道发送信息给这些用户，而用户将在这个子载波上最高的SNR值反馈回源节点；实现了在发送端通过对比各用户所计算反馈回的信噪比值，将这个子载波分配给具有最高信噪比的用户，减少反馈量；设计了在其它用户信道上添加人工噪声方法，使得信息能够实现安全传输，完成指定用户的接入功能；利用随机过程的方法，推导出系统安全吞吐量；在窃听信道CSI未知的无线通信系统中，引入非盲波束成形算法，并且对系统的安全容量进行分析。仿真结果表明，论文设计的方法可以达到提高安全容量的目的。69356

毕业论文关键词  OFDM  随机波束成型  通信安全

毕业设计说明书外文摘要

Title    Design of the Algorithms for Access Control          

           based on OFDM                                        

Abstract

In the MIMO wireless communication system, the traditional security method based on modern cryptography has been unable to meet the needs of the development of modern wireless communication technology. This paper designs a secure algorithm based on the characteristics of the communication channel to realize the access function of control of the specified user. The algorithm designs the selection of specified users. The sender sends the random orthogonal beams and each user will send the largest SNR feedback to the sender in this subcarrier. Then the sender will assign the subcarrier to the user who has a maximum signal-to-noise ratio (SNR) by comparing the SNR which comes from the feedback of users. In the meanwhile, we reduce the amount of feedback by utilizing this method; This paper designs a method of safe information transmission that the artificial noise is transmitted on the other channels to ensure the safety of information transmission and complete the access function of the specified user. We derive the safe throughput by taking advantage of the random process method. In this paper, the non-blind beam-forming algorithm is introduced in wireless communication system when CSI of eavesdropper channel is unknown.  The safety capacity of system is also analyzed in this paper. The simulation results show that the thesis design method can achieve the purpose of the improvement of safety capacity. 

Keywords  OFDM  random beamforming  communications security

目   次

1  绪论……………………………………………………………………………………………………… 1

1.1  研究现状分析…………………………………………………………………………………………… 2

1.1.1  OFDM的研究现状…………………………………………………………………………………… 2

1.1.2  随机波束成形的研究现状…………………………………………………………………………… 2