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
Wind energy can be considered a push-driver factor in the integration of renewable energy sources within the concept of smart grids.For its full deployment,it requires a modern telecommunication infrastructure for tra...Wind energy can be considered a push-driver factor in the integration of renewable energy sources within the concept of smart grids.For its full deployment,it requires a modern telecommunication infrastructure for transmitting control signals around the distributed generation,in which,the wireless communication standards stand out for employing modern digital modulation and coding schemes for error correction,in order to guarantee the power plant operability.In some developing countries,such as Brazil,the high penetration of commercial mobile wireless standards GPRS and EGPRS(based on GSM technology)have captivated the interests of the energy sector,and they now seek to perform remote monitoring and control operations.In this context,this article presents a comparative performance analysis of a wireless control system for a wind SRG,when a GPRS or EGPRS data service is employed.The system performance is analyzed by co-simulations,including the wind generator dynamics and the wireless channel effects.The satisfactory results endorse the viability and robustness of the proposed system.展开更多
Considering the need of target positioning,a remote positioning system is designed based on global positioning system(GPS)and general packet radio service(GPRS);The data collection terminal is based on microcontroller...Considering the need of target positioning,a remote positioning system is designed based on global positioning system(GPS)and general packet radio service(GPRS);The data collection terminal is based on microcontroller unit(MCU)PIC24FV301.It uses GPRS network to create wireless link and transmits GPS source information which is collected by LEA-5H board to monitor center on the Internet.The monitor center obtains the target information through processing and analysis of the calculated data.Actual operation results indicate that the designed system has excellent performance and achieves the goal of the remote location.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
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
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Wind energy can be considered a push-driver factor in the integration of renewable energy sources within the concept of smart grids.For its full deployment,it requires a modern telecommunication infrastructure for transmitting control signals around the distributed generation,in which,the wireless communication standards stand out for employing modern digital modulation and coding schemes for error correction,in order to guarantee the power plant operability.In some developing countries,such as Brazil,the high penetration of commercial mobile wireless standards GPRS and EGPRS(based on GSM technology)have captivated the interests of the energy sector,and they now seek to perform remote monitoring and control operations.In this context,this article presents a comparative performance analysis of a wireless control system for a wind SRG,when a GPRS or EGPRS data service is employed.The system performance is analyzed by co-simulations,including the wind generator dynamics and the wireless channel effects.The satisfactory results endorse the viability and robustness of the proposed system.
文摘Considering the need of target positioning,a remote positioning system is designed based on global positioning system(GPS)and general packet radio service(GPRS);The data collection terminal is based on microcontroller unit(MCU)PIC24FV301.It uses GPRS network to create wireless link and transmits GPS source information which is collected by LEA-5H board to monitor center on the Internet.The monitor center obtains the target information through processing and analysis of the calculated data.Actual operation results indicate that the designed system has excellent performance and achieves the goal of the remote location.
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.
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.
