基于时间反演的多用户下行安全传输技术

无线通信是开放的自由空间,窃听用户可能在通信过程中对信息进行窃取.针对多用户下行链路的信息泄露问题,提出一种基于时间反演(time reversal, TR)且采用波束赋形(beam forming, BF)技术优化的安全传输方案.该方案以最大化安全容量为多用户通信准则,建立多输入单输出(multiple-input single-output, MISO)窃听信道模型.一方面基站采用BF技术使信号在指定方向上增强,针对期望用户发送需求信号;另一方面由于TR技术对环境是自适应的,基站的信号在发射之前都要经过TR腔,其空时聚焦性使能量聚焦在合法接收方,保密性能更优.理论分析和仿真结果表明:与已有物理层安全方案相比,所提方案安全容量更高,误比特率更低.

The secure transmission technology based on time reversal for multiuser downlink system

Information may be eavesdropped by eavesdropping users in the process of wireless communication which relies on open free space. To solve the information disclosure problem of multi-user downlink, a secure transmission scheme which is optimized by beam forming(BF) technology on the basis of time reversal(TR) technology is proposed in this paper. This scheme takes the maximization of security capacity as the principle of multiuser communication, builds a multiple input single output(MISO) wiretap channel model. On one hand, the base station uses beam forming technology to make the signals enhanced in the specified direction, and transmit the demand signals to the desired users. On the other hand, the signals of the base station need to pass through the time reversal cavities before being transmitted because of the environment adaptive technique-time reversal, and spatial and temporal focusing characteristics of time reversal technology make the energy focused on the legal receiver to make the performance of security better. The theoretical analysis and simulation results show that the proposed scheme has a higher security capacity and a lower bit error probability.