Cooperative Ambient Backscatter Communications for Green Internet-of-Things
Cooperative Ambient Backscatter Communications for Green Internet-of-Things
复制标题
绿色物联网的协作环境反向散射通信
DOI：
10.1109/jiot.2018.2799848
复制
发表时间：
2018-04-01
影响因子：
10.6
通讯作者：
Liang, Ying-Chang
中科院分区：
文献类型：
--
作者：
Yang, Gang;Zhang, Qianqian;Liang, Ying-Chang
环境后向散射通信(AMBC)使被动后向散射设备能够利用环境射频信号将信息传输到阅读器，并已成为绿色物联网(IoT)的一种有前途的解决方案。传统的AMBC接收机只对从环境后向散射设备(A-BD)恢复信息感兴趣。在本文中，我们提出了一种协作AMBC(CABC)系统，其中阅读器不仅可以从A-BD恢复信息，还可以从射频源恢复信息。首先从扩频和频谱共享的角度建立了CABC系统的系统模型。然后，对于平坦衰落信道，我们推导了最优最大似然(ML)检测器、次优线性检测器以及基于连续干扰消除(SIC)的检测器。针对频率选择性衰落信道，建立了CABC系统在环境正交频分复用载波下的系统模型，并在此基础上推导出了一种低复杂度的最优ML检测器。对于这两种信道，所提出的检测器的误码率表达式都是闭合形式的。大量的数值结果表明，当A-BD信号和射频源信号具有相同的符号周期时，所提出的基于SIC的检测器在典型应用场景中可以达到接近最大似然检测的性能；当A-BD符号周期长于射频源符号周期时，CABC系统中后向散射信号的存在可以提高射频源信号的ML检测性能，这要归功于A-BD以低于射频源的速率传输时的后向散射链路的有益效果。
Ambient backscatter communication (AmBC) enables a passive backscatter device to transmit information to a reader using ambient RF signals, and has emerged as a promising solution to green Internet-of-Things (IoT). Conventional AmBC receivers are interested in recovering the information from the ambient backscatter device (A-BD) only. In this paper, we propose a cooperative AmBC (CABC) system in which the reader recovers information not only from the A-BD, but also from the RF source. We first establish the system model for the CABC system from spread spectrum and spectrum sharing perspectives. Then, for flat fading channels, we derive the optimal maximum-likelihood (ML) detector, suboptimal linear detectors as well as successive interference-cancellation (SIC) based detectors. For frequency-selective fading channels, the system model for the CABC system over ambient orthogonal frequency division multiplexing carriers is proposed, upon which a low-complexity optimal ML detector is derived. For both kinds of channels, the bit-error-rate expressions for the proposed detectors are derived in closed forms. Finally, extensive numerical results have shown that, when the A-BD signal and the RF-source signal have equal symbol period, the proposed SIC-based detectors can achieve near-ML detection performance for typical application scenarios, and when the A-BD symbol period is longer than the RF-source symbol period, the existence of backscattered signal in the CABC system can enhance the ML detection performance of the RF-source signal, thanks to the beneficial effect of the backscatter link when the A-BD transmits at a lower rate than the RF source.