《通信工程毕业论文1.doc》由会员分享，可在线阅读，更多相关《通信工程毕业论文1.doc（14页珍藏版）》请在三一文库上搜索。
1、毕 业 设 计（论 文）外 文 参 考 资 料 及 译 文译文题目： TD-SCDMA与WCMA网络优化分析 3G network optimization 学生姓名： 周阳 学号： 0821113923 专业： 通信工程 所在学院： 龙蟠学院 指导教师： 徐友法 职称： 讲师 2011年 12 月 1 日说明：要求学生结合毕业设计（论文）课题参阅一篇以上的外文资料，并翻译至少一万印刷符（或译出3千汉字）以上的译文。译文原则上要求打印（如手写，一律用400字方格稿纸书写），连同学校提供的统一封面及英文原文装订，于毕业设计（论文）工作开始后2周内完成，作为成绩考核的一部分。3G network
2、optimization摘自TD-SCDMA无线网络优化原理及方法One, the basic process of 3G network optimizationOperators aim is to build a profitable network, they are very concerned about the network construction, expansion and upgrade in the process of investment cost and its final performance, but the expansion, upgrade cost
3、s and network performance is a pair of contradiction. Construction cost budget and control can get relatively accurate numerical, but the performance of the network is composed of many subjective and objective factors. On one hand, the network capacity expansion, upgrading and upgrades to existing u
4、sers can guarantee the normal use, on the other hand, it also can provide competitive new business, and makes further expansion, upgrading and upgrades can be carried out smoothly. In this way, the network optimization becomes a long-term, iterative process.Network optimization should be able to acc
5、ording to the operators specific needs by means of software tool automatically, can also through manual intervention to achieve the capacity, coverage, QoS ensure a balance point. 3G network system structure is shown in figure 1. Generally, network and includes 3 levels:On Node B, the mobile station
6、 performance indicators for real-time calculation and simulation, including fast power control, rapid congestion resolved, wireless link adaptive, channel allocation;Real time load analysis and control;Based on experience or statistical results, through roadshow, network optimization software for ne
7、twork performance prediction.In front of 2 levels, in the network is completed, by the network management system through the online monitoring and statistics in real time automatic adjustment, while the third level is the need for professionals to carry out, also is we often say that the network opt
8、imization.Artificial network optimization can be divided into the following several steps:First of all, the operator should be based on their own characteristics the definition of a good network optimization is completed to achieve the goal, which determine the above mentioned balance point, includi
9、ng point-to-point quality objectives, different business types of performance indicators and related KPI ( key performance indicators) of various values; later, the existing network performance index data acquisition, through a variety of channels, such as network management system and the convergen
10、ce device feedback, protocol analyzers and even maintenance department customer complaints such as summary, in conclusion, should be through a variety of ways, using a variety of means, collecting more data, the analysis result is accurate.The collected data is input to the network planning software
11、 analysis, can generate the current network status, or achieve some indexes are needed for network configuration. In the process of system simulation, some results in the initial analysis is complete, the error will be relatively large, at this time, some parameters are fine-tuned, local iterative a
12、nalysis of system, it was repeatedly modified, will eventually get accurate results.Network optimization to achieve the purpose of including: improving network coverage, reduce the system call drop rate, loss rate, improve the switching success rate, on Node B load adjustment, optimization of Node B
13、 pilot frequency distribution. Optimization of indicators include: Node B sector transmission power, antenna height and angle, the adjacent Node B position and the pilot signal, the adjacent Node B pilot search window size, trigger switch threshold value.In the process of network optimization, we ne
14、ed to use different tools, and these tools have different effects.1 planning softwareIn detail simulation process, we will be new or expansion, upgrading the site information input to the electronic map. Through repeated simulation and tuning, resulting in some constraints ( such as site location, d
15、etermining fixed configuration ), optimal coverage, capacity, quality of service indicators. Land use planning software optimization stage, through the simulation to determine the system factors include: Node B site, type of antenna, antenna angle. On the basis of the existing network expansion, upg
16、rade, the operator is always concerned with optimization is completed, the new capacity can achieve the simulation predicted value.2 network management systemNetwork management system is to monitor network performance, the system data acquisition. It can be shown that the distribution business, the
17、business such as the quality of call loss rate statistics, therefore, can help the maintenance engineer for fault location.QoS indexes are relatively flexible, according to KPI requirements or cost control requirements, can be identified in the corresponding QoS index. The constraints include: hardw
18、are resources ( channel capacity configuration ), software resources ( interference caps ), call loss rate, dropped call rate, call rate, handover success rate, the uplink / downlink channel load, data retransmission / delay, data and circuit type business rate etc. To meet these requirements, netwo
19、rk management system should have the following 3 functions:( 1) monitoring network traffic and performance;( 2) real-time fault detection and rapid positioning, in order to improve the quality of service;( 3 ) automatically collected, aggregated data required for network planning.3 simulation tool s
20、oftwareAiming at the existing network operation, through the specialized test software tools, we can draw some area or the whole network performance, through simulation analysis software, the various indicators of classification statistics, network optimization engineer to do a detailed assessment o
21、f the overall network performance. Analysis software through the network access to wireless link index, total co-channel interference, and statistical analysis. Some of these data is random, such as a mobile station to a receiving level value, receiving / transmitting power. While some other indicat
22、ors are static, such as switching time, switching rate of success, the statistical analysis of the results can help the network optimization engineer on the existing network conditions have a clear understanding, and targeted for network optimization.Network planning and optimization is a repeated o
23、peration, according to the actual situation and needs, which are theoretically analyzed and calculated, and through the practice of repeatedly correcting.In two, WCDMA and TD-SCDMA network optimization of similarities and differencesIn general, the configuration of hardware design and planning and p
24、roduct parameters have direct relation, such as a radio link antenna gain, isolation, baseband signal electric equality. This aspect of the planning and design to the antenna azimuth, pitch angle, height etc. Radio resource management ( RRM ) includes switching control, power control, control, load
25、control and so on. And according to the different business model, channel mode and system, design and optimization software to use different algorithms. For 3G system, 3 kinds of international standard, in the business model, channel model of the two is exactly the same, but the system in different
26、wireless modulation, different physical layer technology determines the different radio propagation model.The TD-SCDMA and 3GPP recommended by the other 3G standards, technical differences reflected in the smart antenna, joint detection, uplink / downlink synchronization, special frame structure etc
27、. Therefore, network planning and optimization with other system in the reference model is slightly different, and among them, the smart antenna is introduced to analysis result.Therefore, for the TD-SCDMA system, network optimization more should consider the channel allocation algorithm, intelligen
28、t antenna indicator features. Below, we on the TD-SCDMA and WCDMA optimization in several ways are compared.The 1 switchSwitch design for each mobile communication network are very important. From cyber source use efficiency perspective, mobile station not in the best business sector, largely influe
29、nce the quality of the business. For example, a Node B pilot signal is too strong, around the mobile station will often switch to the sector, causing the Node B wireless resources are occupied, the system load is too large, will increase the area of the drop rate, at the same time, area of the inter
30、ferences between mobile stations will increase.In the system of WCDMA, same frequency switching using soft switching ( soft / softer handoff ) manner, in TD-SCDMA, is the use of relay switching ( Baton Handover ), which is a kind of hard switching and soft switching between a switching mode. TD-SCDM
31、A is also one of the core technologies in mobile communication system. Its design concept is the use of smart antenna and uplink synchronization technology, the mobile station distance and azimuth positioning based on mobile station, according to the bearing and distance information as auxiliary inf
32、ormation to determine whether the mobile station mobile to be switched between adjacent Node B neighborhood. If the mobile station enters the switching region, RNC notifies the Node B to switch to prepare, so as to achieve rapid, reliable and efficient switching purposes. This process is a track and
33、 field competition in the relay race relay baton, figure ground says for relay switch. Relay switch with intelligent antenna and uplink synchronization technology, soft switching high success rate and hard switching high channel utilization together, is a good system performance optimization of the
34、switching method.According to the TD-SDMA switch, in the planning and optimization to consider the following points.( 1) the measurement of different switching range.( 2) in the other system, when switching, Node B does not know the exact location of the mobile station and moving direction. RNC noti
35、fied to all Node B measured in a mobile station signal level, whereas in TD-SCDMA, Node B on the signal level measurement based on its current location, RNC according to its moving direction, only to inform their most likely near the Node B measurement. If the mobile station speed, change of directi
36、on very quickly, measuring time delay and network load is relatively large, the relay switch and the effect of WCDMA soft switching effect, conversely, if the district range is too small, easily occur Hou selected pilot area of signal loss, system call drop rate will increase.(3 ) for the purpose of
37、 signal strength measurement delay in switching area.( 4) relay switching and soft switching, is aimed at with the original community maintain communication at the same time, and will switch to the community to establish a connection. But in order to reduce the switching time, its judgments than sof
38、t handoff more strict. If the current cell service quality is relatively high, the mobile station can increase the adjacent Node B signal level measurement interval, when the district service quality decline, the mobile station on the adjacent Node B signal level measuring interval will be reduced.
39、Therefore, in the TD-SCDMA, there is a strong pilot signal Node B is not necessarily the mobile business service Node B. But in WCDMA, switching occurs always in the pilot signal strength as the basis of decision.2 channel allocationWCDMA channel allocation is relatively simple, in the same frequenc
40、y channel allocation in the same order system. But in the TD-SCDMA system, using dynamic channel assignment ( DCA ) method, system in any one physical channel is through its carrier frequency / time / spread spectrum code combination to tag. Channel assignment is actually a radio resource allocation
41、 process.The technology of DCA, the channel is not fixed to a small, but are lumped together for distribution; as long as it can provide enough link quality, any area is the channel to call. DCA has a high utilization rate of the frequency band, without channel planning, can automatically adapt to t
42、he network load and interference changes etc. The drawback is that, DCA algorithm is compared to FCA ( fixed channel allocation ) is more complex, the system overhead is relatively large.The DCA algorithm is divided into slow and fast slow DCA DCA DCA, wireless channel allocation to the District, an
43、d rapid DCA channel to business. RNC management area of available resources, and the dynamic allocation to the user, specific distribution depends on the system load, the business requirements of QoS parameters. Therefore, there are many kinds of DCA algorithm. The most used is based on the interfer
44、ence measurement of DCA algorithm, this algorithm according to the mobile station feedback real-time interference measurement results distribution channel.A good DCA algorithm can improve the bandwidth utilization rate, and can adaptively reduce the system load, but also save the network planning in
45、 the planning and distribution channel link. However, if the use of DCA algorithm is inconsistent with the actual situation, would run counter to ones desire.3 smart antennaIn the TD system, if not using smart antenna, to a user, the same time slot in the useful signal other than the signal power is
46、 affecting the quality of communication interference and noise; the beam shaping, only from the main valve and larger sidelobe interference will affect user signal. Smart antenna beam shaping effectively reduces the interference between users, its essence is to different user signal in space to dist
47、inguish.Smart antenna for TD-SCDMA network performance impact is very big, accordingly, in the DCA algorithm needs to consider the space division multiplexing ( SCDM ). The power control, breathing effect range, interference control algorithm and WCDMA, smart antenna is used in the handoff algorithm
48、 in some criterion relationship becomes fuzzy and complicated, parameter measurement of random factors, such as the mobile users location, such as the effect of intelligent antenna. Cell breathing effect more randomization, the switch region is randomization.4 indoor coverageIn the WCDMA system, for hot spot coverage, especially the construction of large indoor coverage, the widespread use of indoor signal distribution system. In the indoor ceiling mounted