基于信道状态信息的后向散射信号检测

为了实现Wi Fi环境后向散射系统中后向散射信号的检测,提出了2种检测方案。首先通过对Wi Fi后向散射系统的建模和分析,基于Wi Fi上行链路的IEEE802.11a标准提出了一种常规检测方案;方案在信道估计中,利用接收到的长训练序列和短训练序列以获得信道状态信息,Wi Fi阅读器利用这个信道状态信息通过后向散射标签检测编码数据,从而实现检测功能;为了进一步提高检测阈值的质量,提出了在Wi Fi阅读器上采用多个接收Wi Fi信号的天线的改进检测方案,并通过对多个接收信号进行平均运算以提高接收信号的信噪比,从而进一步提高检测性能。仿真实验结果表明,提出的2种检测方案不仅能够实现对Wi Fi环境后向散射信号的有效检测,而且还增大了检测距离。

Backscattering signal detection based on channel state information

For detecting the backscattering signal in WiFi ambient backscattering system,two detection schemes are proposed in this paper. By modeling and analyzing WiFi backscattering system,a conventional detection scheme based on IEEE802. 11 a standard of WiFi uplink is proposed. In the channel estimation,the scheme uses the long training sequence and the short training sequence to obtain the channel state information,and the WiFi reader uses the channel state information to detect the encoded data by the backscatter tag,so as to implement the detection function. In order to further improve the quality of detection thresholds,an improved detection scheme using multiple antennas receiving WiFi signals on WiFi readers is proposed,and the signal to noise power ratio of received signals is improved by the average operation of multiple received signals. Thus,the detection performance is further improved. Simulation results show that the proposed two detection schemes not only effectively detect the WiFi ambient backscattering signal,but also increase the detection distance.