城市地下管廊内布设了大量的管线,如燃气管道、网络通讯线路、电力线路等,由于地下环境复杂多变,存在着气体泄漏、爆炸、火灾等安全风险。针对这些问题,提出一种基于窄带物联网技术(Narrow Band Internet of Things,NB-IoT)的地下管廊...城市地下管廊内布设了大量的管线,如燃气管道、网络通讯线路、电力线路等,由于地下环境复杂多变,存在着气体泄漏、爆炸、火灾等安全风险。针对这些问题,提出一种基于窄带物联网技术(Narrow Band Internet of Things,NB-IoT)的地下管廊环境监测系统。该系统采用先进的传感器技术、NB-IoT技术、软件技术,系统主要分为数据采集模块、物联网云平台、远程监测系统三部分。数据采集模块以STM32作为主控单元连接各个传感器,采集温度、湿度、水位、可燃气体等数据,经过处理后利用NB-IoT网络上传到物联网云平台,远程监测系统调用物联网云平台的数据接口进行远程显示与预警。实验结果表明,系统在降低系统总体功耗的同时,能够实时、稳定地进行地下管廊环境监测,提前预防可能存在的风险。展开更多
随着物联网技术的飞速发展,窄带物联网(Narrow Band Internet of Things,NB-IoT)作为一种低功耗、广覆盖、大连接的无线通信技术,逐渐成为连接物理世界与数字世界的桥梁。然而,在实际应用中,NB-IoT信号面临着诸如信号衰减、干扰、覆盖...随着物联网技术的飞速发展,窄带物联网(Narrow Band Internet of Things,NB-IoT)作为一种低功耗、广覆盖、大连接的无线通信技术,逐渐成为连接物理世界与数字世界的桥梁。然而,在实际应用中,NB-IoT信号面临着诸如信号衰减、干扰、覆盖不均等挑战。这些挑战不仅影响用户体验,还限制了物联网应用的进一步发展。因此,研究面向物联网的NB-IoT信号优化方法具有重要意义。文章深入研究面向物联网的NB-IoT信号优化方法,提出多种有效的优化策略和技术手段。展开更多
NB-IoT(Narrow Band Internet of Things)是基于蜂窝窄带物联网的一种新兴技术,是物联网的一个重要分支。随着NB-IoT终端设备的规模不断增大,物联网安全面临数据泄露、中间人攻击等安全威胁。本论文针对NB-IoT技术的数据安全传输研究,...NB-IoT(Narrow Band Internet of Things)是基于蜂窝窄带物联网的一种新兴技术,是物联网的一个重要分支。随着NB-IoT终端设备的规模不断增大,物联网安全面临数据泄露、中间人攻击等安全威胁。本论文针对NB-IoT技术的数据安全传输研究,从物联网终端安全和应用服务安全两方面进行分析,结合密码技术给出了NB-IoT系统安全模型,提出了基于物联网应用层数据信源加密传输机制,给出了轻量级身份认证协议和数据加密传输协议,论证了该方案的安全性,通过实验验证了所提方案的可行性和适用性。展开更多
Backscatter communications will play an important role in connecting everything for beyond 5G(B5G)and 6G systems.One open challenge for backscatter communications is that the signals suffer a round-trip path loss so t...Backscatter communications will play an important role in connecting everything for beyond 5G(B5G)and 6G systems.One open challenge for backscatter communications is that the signals suffer a round-trip path loss so that the communication distance is short.In this paper,we first calculate the communication distance upper bounds for both uplink and downlink by measuring the tag sensitivity and reflection coefficient.It is found that the activation voltage of the envelope detection diode of the downlink tag is the main factor limiting the back-scatter communication distance.Based on this analysis,we then propose to implement a low-noise amplifier(LNA)module before the envelope detection at the tag to enhance the incident signal strength.Our experimental results on the hardware platform show that our method can increase the downlink communication range by nearly 20 m.展开更多
随着物联网技术的快速发展,低功率广域网络(Low-Power Wide-Area Network,LPWAN)以其特有的优势得到广泛的应用。在众多的LPWAN技术应用场景中,地磁作为无线传感器被应用于各种停车管理的场景中,其中,国内停车行业关注度最高的是远距离...随着物联网技术的快速发展,低功率广域网络(Low-Power Wide-Area Network,LPWAN)以其特有的优势得到广泛的应用。在众多的LPWAN技术应用场景中,地磁作为无线传感器被应用于各种停车管理的场景中,其中,国内停车行业关注度最高的是远距离无线电(Long Range Radio,Lo Ra)和窄带物联网(Narrow Band Internet of Things,NB-Io T)两种通信技术的地磁。本文旨在从地磁的Lo Ra与NB-Io T通信技术方面进行系统的梳理和比较分析,为地磁的选择应用提供有力的技术参考和储备。展开更多
In this paper,we investigate covert communications in data collected IoT with NOMA,where the paired sensor nodes S_(m) and S_(n) transmit covert messages to a legitimate receiver(Bob)in the presence of a Warden(Willie...In this paper,we investigate covert communications in data collected IoT with NOMA,where the paired sensor nodes S_(m) and S_(n) transmit covert messages to a legitimate receiver(Bob)in the presence of a Warden(Willie).To confuse the detection at Willie,an extra multi-antenna friendly jammer(Jammer)has been employed to transmit artificial noise(AN)with random power.Based on the CSI of Willie is available or not at Jammer,three AN transmission schemes,including null-space artificial noise(NAN),transmit antenna selection(TAS),and zeroforcing beamforming(ZFB),are proposed.Furthermore,the closed-form expressions of expected minimum detection error probability(EMDEP)and joint connection outage probability(JCOP)are derived to measure covertness and reliability,respectively.Finally,the maximum effective covert rate(ECR)is obtained with a given covertness constraint.The numerical results show that ZFB scheme has the best maximum ECR in the case of the number of antennas satisfies N>2,and the same maximum ECR can be achieved in ZFB and NAN schemes with N=2.Moreover,TAS scheme also can improve the maximum ECR compared with the benchmark scheme(i.e.,signal-antenna jammer).In addition,a proper NOMA node pairing can further improve the maximum ECR.展开更多
文摘城市地下管廊内布设了大量的管线,如燃气管道、网络通讯线路、电力线路等,由于地下环境复杂多变,存在着气体泄漏、爆炸、火灾等安全风险。针对这些问题,提出一种基于窄带物联网技术(Narrow Band Internet of Things,NB-IoT)的地下管廊环境监测系统。该系统采用先进的传感器技术、NB-IoT技术、软件技术,系统主要分为数据采集模块、物联网云平台、远程监测系统三部分。数据采集模块以STM32作为主控单元连接各个传感器,采集温度、湿度、水位、可燃气体等数据,经过处理后利用NB-IoT网络上传到物联网云平台,远程监测系统调用物联网云平台的数据接口进行远程显示与预警。实验结果表明,系统在降低系统总体功耗的同时,能够实时、稳定地进行地下管廊环境监测,提前预防可能存在的风险。
文摘随着物联网技术的飞速发展,窄带物联网(Narrow Band Internet of Things,NB-IoT)作为一种低功耗、广覆盖、大连接的无线通信技术,逐渐成为连接物理世界与数字世界的桥梁。然而,在实际应用中,NB-IoT信号面临着诸如信号衰减、干扰、覆盖不均等挑战。这些挑战不仅影响用户体验,还限制了物联网应用的进一步发展。因此,研究面向物联网的NB-IoT信号优化方法具有重要意义。文章深入研究面向物联网的NB-IoT信号优化方法,提出多种有效的优化策略和技术手段。
文摘NB-IoT(Narrow Band Internet of Things)是基于蜂窝窄带物联网的一种新兴技术,是物联网的一个重要分支。随着NB-IoT终端设备的规模不断增大,物联网安全面临数据泄露、中间人攻击等安全威胁。本论文针对NB-IoT技术的数据安全传输研究,从物联网终端安全和应用服务安全两方面进行分析,结合密码技术给出了NB-IoT系统安全模型,提出了基于物联网应用层数据信源加密传输机制,给出了轻量级身份认证协议和数据加密传输协议,论证了该方案的安全性,通过实验验证了所提方案的可行性和适用性。
基金supported in part by National Natural Science Foundation of China under Grant Nos.61971029 and U22B2004in part by Beijing Municipal Natural Science Foundation under Grant No.L222002.
文摘Backscatter communications will play an important role in connecting everything for beyond 5G(B5G)and 6G systems.One open challenge for backscatter communications is that the signals suffer a round-trip path loss so that the communication distance is short.In this paper,we first calculate the communication distance upper bounds for both uplink and downlink by measuring the tag sensitivity and reflection coefficient.It is found that the activation voltage of the envelope detection diode of the downlink tag is the main factor limiting the back-scatter communication distance.Based on this analysis,we then propose to implement a low-noise amplifier(LNA)module before the envelope detection at the tag to enhance the incident signal strength.Our experimental results on the hardware platform show that our method can increase the downlink communication range by nearly 20 m.
文摘随着物联网技术的快速发展,低功率广域网络(Low-Power Wide-Area Network,LPWAN)以其特有的优势得到广泛的应用。在众多的LPWAN技术应用场景中,地磁作为无线传感器被应用于各种停车管理的场景中,其中,国内停车行业关注度最高的是远距离无线电(Long Range Radio,Lo Ra)和窄带物联网(Narrow Band Internet of Things,NB-Io T)两种通信技术的地磁。本文旨在从地磁的Lo Ra与NB-Io T通信技术方面进行系统的梳理和比较分析,为地磁的选择应用提供有力的技术参考和储备。
基金supported by the National Natural Science Foundation of China under Grant(no.62071486,no.61771487,no.62171464).
文摘In this paper,we investigate covert communications in data collected IoT with NOMA,where the paired sensor nodes S_(m) and S_(n) transmit covert messages to a legitimate receiver(Bob)in the presence of a Warden(Willie).To confuse the detection at Willie,an extra multi-antenna friendly jammer(Jammer)has been employed to transmit artificial noise(AN)with random power.Based on the CSI of Willie is available or not at Jammer,three AN transmission schemes,including null-space artificial noise(NAN),transmit antenna selection(TAS),and zeroforcing beamforming(ZFB),are proposed.Furthermore,the closed-form expressions of expected minimum detection error probability(EMDEP)and joint connection outage probability(JCOP)are derived to measure covertness and reliability,respectively.Finally,the maximum effective covert rate(ECR)is obtained with a given covertness constraint.The numerical results show that ZFB scheme has the best maximum ECR in the case of the number of antennas satisfies N>2,and the same maximum ECR can be achieved in ZFB and NAN schemes with N=2.Moreover,TAS scheme also can improve the maximum ECR compared with the benchmark scheme(i.e.,signal-antenna jammer).In addition,a proper NOMA node pairing can further improve the maximum ECR.
