提出一个基于GPRS(G enera l Packet R ad io Serv ice)网络的远程数据传输方案,将远端的各种传感器数据及时发送给监控中心,同时实现了远程控制、远程唤醒等移动终端的功能,监视被监控点的动态信息,并给出了数据链接的AT命令和数据传...提出一个基于GPRS(G enera l Packet R ad io Serv ice)网络的远程数据传输方案,将远端的各种传感器数据及时发送给监控中心,同时实现了远程控制、远程唤醒等移动终端的功能,监视被监控点的动态信息,并给出了数据链接的AT命令和数据传输时间的实验数据.展开更多
为了实现大规模、多区域的可燃气体的统一监测预警,使用无线传感器网络自组网技术、通用分组无线业务(general packet radio service,GPRS)无线传输技术和服务器数据库设计了可燃气体报警器采集节点、可燃气体报警器汇聚传输节点并完成...为了实现大规模、多区域的可燃气体的统一监测预警,使用无线传感器网络自组网技术、通用分组无线业务(general packet radio service,GPRS)无线传输技术和服务器数据库设计了可燃气体报警器采集节点、可燃气体报警器汇聚传输节点并完成服务器云管理平台的搭建.温湿度补偿算法提高了可燃气体报警器的采集精度,多级报警策略使可燃气体预警更智能,数据传输加密算法使数据传输更安全.系统可以应用在居民小区环境对可燃气体泄露智能预警.相关管理部门根据服务器云管理平台对预警信息及时处理并长期对监测数据进行统计分析.最后对搭建的远程可燃气体监测预警系统进行应用测试.结果表明:系统丢包率和用户收到预警信息时间间隔都满足可燃气体预警的实际要求.展开更多
In cognitive radio networks(CoR),the performance of cooperative spectrum sensing is improved by reducing the overall error rate or maximizing the detection probability.Several optimization methods are usually used to ...In cognitive radio networks(CoR),the performance of cooperative spectrum sensing is improved by reducing the overall error rate or maximizing the detection probability.Several optimization methods are usually used to optimize the number of user-chosen for cooperation and the threshold selection.However,these methods do not take into account the effect of sample size and its effect on improving CoR performance.In general,a large sample size results in more reliable detection,but takes longer sensing time and increases complexity.Thus,the locally sensed sample size is an optimization problem.Therefore,optimizing the local sample size for each cognitive user helps to improve CoR performance.In this study,two new methods are proposed to find the optimum sample size to achieve objective-based improved(single/double)threshold energy detection,these methods are the optimum sample size N^(*)and neural networks(NN)optimization.Through the evaluation,it was found that the proposed methods outperform the traditional sample size selection in terms of the total error rate,detection probability,and throughput.展开更多
Several channel de-allocation schemes for GSM/GPRS(General Packet Radio Service) networks are proposed in this paper. For DRA (Dynamical Resource Allocation) with de-allocation mechanism, if a new voice call arrives a...Several channel de-allocation schemes for GSM/GPRS(General Packet Radio Service) networks are proposed in this paper. For DRA (Dynamical Resource Allocation) with de-allocation mechanism, if a new voice call arrives and finds that all the channels are busy,then one of the GPRS packets which occupy more than one channel for data transmission may release a channel for the new voice call. This paper presents 5 de-allocation mechanisms, i.e.DA-RANDOM, DA-RICHEST, DA-POOREST, DA-OLDEST and DA-YOUNGEST, to select the GPRS packet for releasing the appropriate channel. Simulation results show that DAOLDEST achieves the best performance, especially in packets blocking probability, among all the de-allocation schemes. Although the performance of the proposed de-allocation schemes is not significantly different, they are all much better than that of the scheme without de-allocation.展开更多
In a cognitive radio network, the secondary users can use the spectrum holes when the primary users do not utilize the spectrum, but they must vacant the spectrum when the primary users need to transmit data on the sp...In a cognitive radio network, the secondary users can use the spectrum holes when the primary users do not utilize the spectrum, but they must vacant the spectrum when the primary users need to transmit data on the spectrum. In other words, the primary users have higher priority over the secondary users. In this paper, backlog and delay distribution bounds for both primary users and secondary users are obtained. The analysis is based on stochastic network calculus, for which, stochastic service curves are t-n-st derived for both primary users and secondary users, and the network calculus independent case analysis approach is used to find the distribution bounds. Numerical results and simulation results are also presented and discussed.展开更多
Aiming at the inaccessible problem of remote embedded devices update and maintenance, this paper presents a method using general packet radio service (GPRS) to achieve update based on the embedded real-time operatin...Aiming at the inaccessible problem of remote embedded devices update and maintenance, this paper presents a method using general packet radio service (GPRS) to achieve update based on the embedded real-time operating system (RTOS) μC/OS-Ⅱ. It introduces architecture of the system first. And then it uses LPC1768 chip as the central processing unit, SIM900A module for data transmission, and SST25VF016B to store the data. To ensure accuracy of the data transmis- sion, cyclic redundancy code (CRC) is adopted. The software uses fixed bootstrap and mutable update program, and thus the embedded devices can still normally start in case of update failure. Finally, high stability and extensive adaptability of the system are verified by experimental data.展开更多
文摘为了实现大规模、多区域的可燃气体的统一监测预警,使用无线传感器网络自组网技术、通用分组无线业务(general packet radio service,GPRS)无线传输技术和服务器数据库设计了可燃气体报警器采集节点、可燃气体报警器汇聚传输节点并完成服务器云管理平台的搭建.温湿度补偿算法提高了可燃气体报警器的采集精度,多级报警策略使可燃气体预警更智能,数据传输加密算法使数据传输更安全.系统可以应用在居民小区环境对可燃气体泄露智能预警.相关管理部门根据服务器云管理平台对预警信息及时处理并长期对监测数据进行统计分析.最后对搭建的远程可燃气体监测预警系统进行应用测试.结果表明:系统丢包率和用户收到预警信息时间间隔都满足可燃气体预警的实际要求.
基金This research was funded by Princess Nourah bint Abdulrahman University Researchers Supporting Project Number(PNURSP2022R97),Princess Nourah bint Abdulrahman University,Riyadh,Saudi Arabia.
文摘In cognitive radio networks(CoR),the performance of cooperative spectrum sensing is improved by reducing the overall error rate or maximizing the detection probability.Several optimization methods are usually used to optimize the number of user-chosen for cooperation and the threshold selection.However,these methods do not take into account the effect of sample size and its effect on improving CoR performance.In general,a large sample size results in more reliable detection,but takes longer sensing time and increases complexity.Thus,the locally sensed sample size is an optimization problem.Therefore,optimizing the local sample size for each cognitive user helps to improve CoR performance.In this study,two new methods are proposed to find the optimum sample size to achieve objective-based improved(single/double)threshold energy detection,these methods are the optimum sample size N^(*)and neural networks(NN)optimization.Through the evaluation,it was found that the proposed methods outperform the traditional sample size selection in terms of the total error rate,detection probability,and throughput.
基金Supported by the NSFC/RGC joint research scheme (No.60218001/N_HKUST617-02).
文摘Several channel de-allocation schemes for GSM/GPRS(General Packet Radio Service) networks are proposed in this paper. For DRA (Dynamical Resource Allocation) with de-allocation mechanism, if a new voice call arrives and finds that all the channels are busy,then one of the GPRS packets which occupy more than one channel for data transmission may release a channel for the new voice call. This paper presents 5 de-allocation mechanisms, i.e.DA-RANDOM, DA-RICHEST, DA-POOREST, DA-OLDEST and DA-YOUNGEST, to select the GPRS packet for releasing the appropriate channel. Simulation results show that DAOLDEST achieves the best performance, especially in packets blocking probability, among all the de-allocation schemes. Although the performance of the proposed de-allocation schemes is not significantly different, they are all much better than that of the scheme without de-allocation.
文摘In a cognitive radio network, the secondary users can use the spectrum holes when the primary users do not utilize the spectrum, but they must vacant the spectrum when the primary users need to transmit data on the spectrum. In other words, the primary users have higher priority over the secondary users. In this paper, backlog and delay distribution bounds for both primary users and secondary users are obtained. The analysis is based on stochastic network calculus, for which, stochastic service curves are t-n-st derived for both primary users and secondary users, and the network calculus independent case analysis approach is used to find the distribution bounds. Numerical results and simulation results are also presented and discussed.
文摘Aiming at the inaccessible problem of remote embedded devices update and maintenance, this paper presents a method using general packet radio service (GPRS) to achieve update based on the embedded real-time operating system (RTOS) μC/OS-Ⅱ. It introduces architecture of the system first. And then it uses LPC1768 chip as the central processing unit, SIM900A module for data transmission, and SST25VF016B to store the data. To ensure accuracy of the data transmis- sion, cyclic redundancy code (CRC) is adopted. The software uses fixed bootstrap and mutable update program, and thus the embedded devices can still normally start in case of update failure. Finally, high stability and extensive adaptability of the system are verified by experimental data.