基于DSSS-LFM-FRFT的ZigBee网络中抗RFID干扰研究

针对传统解决ZigBee/RFID(radio frequency identification)2种设备的信号同频干扰问题，采用信道调度算法存在频谱资源利用率低、通信效率低等问题，量化分析了两者信号冲突成因，并提出了基于直接序列扩频再线性调频的分数阶傅里叶变换自适应抗干扰方法(direct sequence spread spectrum-linear frequency modulation-fractional Fourier transform，DSSS-LFM-FRFT)。该方法将传统的ZigBee直接序列扩频技术进行改进，当系统检测到信号干扰时，在接收机解扩之前进行干扰抑制，通过线性调频再扩频技术展宽ZigBee信道信号频谱，接收机前端利用分数阶傅里叶变换滤除掉干扰信号之后再进行分数阶傅里叶逆变换，通过解扩还原信号。实验结果表明，该方法与传统DSSS比较，不仅提高了系统的抗干扰能力，还降低了误码率，实现了ZigBee/RFID共存时高效率通信，提高了无线网络频谱资源利用率。

Research on anti-RFID interference in ZigBee network based on DSSS-LFM-FRFT

To solve the problem of co-channel interference of ZigBee/RFID (radio frequency identification) signal, the traditional channel scheduling algorithm shows up underutilization of spectrum resource and low communication efficiency, this paper analyzes the principle of signal collision between the two devices and an adaptive anti-interference method based on fractional fourier transform and direct sequence spread spectrum-linear frequency modulation (DSSS-LFM-FRFT) is proposed. This method improves the traditional DSSS technology of ZigBee, when the system detects interference, the receiver performs interference suppression before despreading. Spreading the channel signal spectrum of the ZigBee network through DSSS-LFM technique, the receiver front-end uses the fractional Fourier transform to filter out the interference signal then performing fractional Fourier inverse transform and restores signal by despreading. The experimental results show that, compared with the traditional DSSS, this method not only improves the anti-interference ability of the system, but also reduces the bit error rate. It can achieve high communication efficiency in the coexistence of ZigBee/RFID, and improve wireless frequency resource utilization.