Department of Electrical and Computer Engineering, University of California at San Diego, La Jolla, CA 92093, USA.
Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon 16419, Korea.
Sensors (Basel). 2019 Oct 28;19(21):4676. doi: 10.3390/s19214676.
This paper presents a duty cycle-based, dual-mode simultaneous wireless information and power transceiver (SWIPT) for Internet of Things (IoT) devices in which a sensor node monitors the received power and adaptively controls the single-tone or multitone communication mode. An adaptive power-splitting (PS) ratio control scheme distributes the received radio frequency (RF) energy between the energy harvesting (EH) path and the information decoding (ID) path. The proposed SWIPT enables the self-powering of an ID transceiver above 20 dBm input power, leading to a battery-free network. The optimized PS ratio of 0.44 enables it to provide sufficient harvested energy for self-powering and energy-neutral operation of the ID transceiver. The ID transceiver can demodulate the amplitude-shift keying (ASK) and the binary phase-shift keying (BPSK) signals. Moreover, for low-input power level, a peak-to-average power ratio (PAPR) scheme based on multitone is also proposed for demodulation of the information-carrying RF signals. Due to the limited power, information is transmitted in uplink by backscatter modulation instead of RF signaling. To validate our proposed SWIPT architecture, a SWIPT printed circuit board (PCB) was designed with a multitone SWIPT board at 900 MHz. The demodulation of multitone by PAPR was verified separately on the PCB. Results showed the measured sensitivity of the SWIPT to be -7 dBm, and the measured peak power efficiency of the RF energy harvester was 69% at 20 dBm input power level. The power consumption of the injection-locked oscillator (ILO)-based phase detection path was 13.6 mW, and it could be supplied from the EH path when the input power level was high. The ID path could demodulate 4-ASK- and BPSK-modulated signals at the same time, thus receiving 3 bits from the demodulation process. Maximum data rate of 4 Mbps was achieved in the measurement.
本文提出了一种基于占空比的物联网（IoT）设备双模式同时无线信息与能量传输（SWIPT）收发器，其中传感器节点监测接收功率，并自适应地控制单音或多音通信模式。一种自适应功率分割（PS）比控制方案将接收到的射频（RF）能量在能量收集（EH）路径和信息解码（ID）路径之间分配。所提出的 SWIPT 使 ID 收发器在输入功率高于 20 dBm 时实现自供电，从而实现无电池网络。优化的 PS 比为 0.44，可为 ID 收发器的自供电和能量中立操作提供足够的能量。ID 收发器可以解调幅移键控（ASK）和二进制相移键控（BPSK）信号。此外，对于低输入功率水平，还提出了基于多音的峰值平均功率比（PAPR）方案，用于解调携带信息的 RF 信号。由于功率有限，信息通过反向散射调制而不是射频信号在上行链路中传输。为了验证我们提出的 SWIPT 架构，设计了一个基于多音的 900 MHz 的 SWIPT 印刷电路板（PCB），并在 PCB 上分别验证了多音的 PAPR 解调。结果表明，SWIPT 的测量灵敏度为-7 dBm，RF 能量收集器的测量峰值功率效率在 20 dBm 输入功率水平下为 69%。基于注入锁定振荡器（ILO）的相位检测路径的功耗为 13.6 mW，当输入功率水平较高时，它可以由 EH 路径供电。ID 路径可以同时解调 4-ASK 和 BPSK 调制信号，从而从解调过程中接收 3 位。在测量中实现了最大 4 Mbps 的数据速率。
