Application Of Oversampling In IoT Wi-Fi

With the proliferation of the Internet and the popularization of cloud computing services,humanity is about to enter the era of the Internet of Things.As an important part of a new generation of information technology,the Internet of Things is predicted to be a technological revolution and economic wave of the global information industry.It is attached great importance by governments,enterprises,and academia.Wi-Fi meets the communication requirements for large-scale access in the Internet of Things due to its high spectrum efficiency.However,the traditional Wi-Fi protocol has a problem of excessive power consumption when used in the Internet of Things directly,which affect the endurance of the Internet of Things terminal equipment Seriously.In order to design a Wi-Fi protocol which suitable for the Internet of Things,researchers from home and abroad have conducted extensive research for it.In response to the excessive power consumption of Wi-Fi protocol when applied to IoT communication,in December 2016,the Wi-Fi Alliance released a low-power long-distance communication protocol 802.1 lah(Wi-Fi HaLow)which specifically designed for IoT communication.802.1 lah adopted a restricted access window mechanism and a target wake time mechanism at the MAC layer which reduces the energy consumption of the Internet of Things terminals effectively.However,we consider that the bottleneck of the uplink energy efficiency of IoT device is the architecture of transceiver.Nowadays,The access point has more powerful computing capabilities and sufficient energy supply than IoT terminal in IoT application.Using a traditional transceiver architecture for IoT communications does not fully utilize the powerful performance advantages of IoT access point devices,it is a waste of access point hardware resources.So,combining the scheme of cellular network we propose a scheme to reduce the power consumption of the IoT device by modifying the architecture of IoT transceiver.It takes full advantage of the strong performance of the access point to oversample the OFDM signal and decode it with the redundancy of the oversampled signal.Through the theoretical analysis and experimental experiments of oversampling OFDM signals we found the correlation between redundant signals and as a breakthrough point for oversampling OFDM signals.Then we designed the synchronization algorithm,frequency offset compensation algorithm and solution for over-sampling OFDM signals modulation algorithm.With this transceiver,the IoT terminal can transmit RF signals with lower power.System places the decoding pressure on the receiver access point device which have powerful computing performance and sufficient energy supply.In the premise that the transceiver communication function well,we reduced the minimum transmission power of transmitter.Finally,USRP software define radio hardware experiment platform were used to build the asymmetric communication architecture,and we realized the synchronization algorithm,frequency offset compensation algorithm and modulation algorithm in GNU Radio software experiment platform.With a series of tests,we verify the feasibility of oversampling Wi-Fi signal demodulation algorithm,and we found that oversampling demodulation algorithm has an outstanding anti-noise capability.Compared with the traditional Wi-Fi protocol,the oversampling Wi-Fi protocol have a better communication performance in low-SNR experimental environment.We found that the performance increase with the increase of oversampling factor,and it can reduce the energy consumption of nearly 70%for transmitting device under the experimental conditions of 8 times the clock frequency.