结构化训练的关键因素 [5]
论文作者:www.51lunwen.org论文属性:作业 Assignment登出时间:2016-05-04编辑:lily点击率:12035
论文字数:3237论文编号:org201605030852016406语种:英语 English地区:台湾价格:免费论文
关键词:塞浦路斯结构化训练电信服务
摘要:本文以作者在塞浦路斯电信局操作与维护服务部门实习的经历来阐述结构化训练的内容、意义及关键因素,通过分析工作情况,最终得出结论,试图给出比较有效的工作训练方法。
. The software allows also the monitoring and control of handovers to other cells. For test runs to record the signal strength in an area, the TEMS equipment is combined with a GPS receiver, that way the field engineer is able to allocate the quality of the signal to the area on the map.
After spending more than half my training period in the operation and maintenance department, I began to visit the other departments in the company. I was given lectures by the different departments as they explained to me the main concept of their work and the basics of how it all works from their part of the company. One of the departments I visited was that responsible for the GPRS system.
GPRS is an applied update of the GSM network, to increase the data rate between the mobile station and the radio base station. The Base Station Subsystem requires a software upgrade of the transceiver unit as well as some other units. In addition, a new hardware unit called a Packet Control Unit (PCU) is added to the BSS to manage the packet data transfer between user devices and the GPRS core network. Furthermore, GPRS adds two new components to the network: the Serving GPRS Support Node (SGSN) and the Gateway GPRS Support Node (GGSN). These nodes interact with the network subsystem and the internet. Also a special channel is reserved in each cell for the control data of the GPRS applications. This package data channel (PDCH) is mapped onto a single time slot and is utilized by the same physical channel structure as the other circuit-switched GSM channels.
The GSM radio technology is based on 200 kHz wide radio channels with a data throughput rate of 9.6 or 14.4 Kbps, depending on the coding scheme supported by the network and terminal device. To increase the data rate, GPRS ties the information into data packets and makes use of unused TDMA timeslots. In theory, up to 8 timeslots can be allocated to one data channel during packet transfer. The maximum theoretical data rate under perfect radio conditions is 171 Kbps. In practical application, the number of allocated channels is reduced by the capability of the mobile station and the number of users in the network. At the moment, mobile stations can use up to 4 channels for uplink and downlink, but a maximum of 5 timeslots at the same time. Depending on the quality of the radio transmission the applied channel coding sequence reduces the data traffic speed again. In this case, one time slot is statically assigned to GPRS. The additional timeslots are dynamically assigned by the BSC, depending on the circuit-switched traffic, which has a priority because it is more time critical than the data traffic of GPRS. Under good radio conditions, this yields speeds of approximately 50 Kbps downstream and 20 Kbps upstream. This is more than three times faster than current 14.4 Kbps GSM networks and roughly equivalent to a good landline analogue modem connection. With its faster data transfer rates, GPRS enables higher bandwidth applications like Multi Message Service (MMS), Push To Talk (PTT), and a faster Wireless Application Protocol (WAP). Moreover, the transfer of Short Message System (SMS) via GPRS is much faster.
The Mobile Stations are connected to the RBS by a virtual “always on” connection, which eliminates the lengthy delays required to reconnect to the network to send and receive data. These means the radio channels are used on demand, so that information
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