高速铁路场景下环境反向散射辅助的无线传输方案

将反向散射技术引入到高铁场景的无线通信系统中，提出一种反向散射辅助无线传输方案（Backscatter Aided Wireless Transmission,BAWT），并针对BAWT和传统无线传输方案（Direct Wireless Transmission,DWT）进行了收发信机设计，包括信道估计以及信号检测。与传统无线传输方案相比，证明了在固定的火车天线和不变的轨道情况下，BAWT可以获得信道统计信息为信道估计提供助力。通过仿真对比两种方案的信道估计均方误差，BAWT方案相较DWT方案的信道估计准确性明显提高；对比BAWT、传统中继技术以及DWT方案，当信噪比为20 dB时，对应的BAWT方案和中继技术、DWT方案的误码率分别为1%和2%和12%，BAWT方案误码检测性能获得明显提升。此外，针对广域环境下的环境反向散射通信，推导了高铁场景下使用蜂窝移动通信信号作为RF信源的无线链路预算，反向散射信号在车厢内的覆盖范围内可以满足接收机的灵敏度要求，从链路预算角度论证了BAWT方案实现的可行性。

Transmission Schemes for Backscatter Aided Wireless Communications on High-speed Railways

The backscatter technology is introduced to the wireless communication system of high-speed railway(HSR).Taking advantage of the low cost of backscatter technology,a backscatter aided wireless transmission scheme(BAWT) is proposed.Transceiver is designed for BAWT scheme and traditional wireless transmission scheme(DWT),including channel estimation and signal detection.Compared with the traditional wireless transmission scheme,it is proved that under the condition of fixed train antenna and constant track,BAWT can obtain channel statistics information to provide assistance for channel estimation.Compared with the channel estimation mean square error of BAWT,DWT,the BAWT scheme has significantly improved channel estimation accuracy according to simulation results.Moreover,compared with the signal detection performance of BAWT,Relay and DWT,bit error rate are 1%,2% and 12% respectively when signal-to-noise ratio(SNR) is 20 dB.It is proved that BAWT scheme improves the error rate detection performance significantly.In addition,for the ambient backscatter communication in the wide area environment,the link budget in the HSR scenario is deduced.It can be seen from the link budget that the backscatter signal can meet the sensitivity requirements of the receiver within the coverage area of the carriage,and the feasibility of BAWT scheme is demonstrated from the perspective of the link budget.