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通信工程畢業(yè)設(shè)計外文翻譯-td-scdma與wcma網(wǎng)絡(luò)優(yōu)化分析(編輯修改稿)

2025-01-07 01:15 本頁面
 

【文章內(nèi)容簡介】 ea of the interferences between mobile stations will increase. In the system of WCDMA, same frequency switching using soft switching ( soft / softer handoff ) manner, in TDSCDMA, is the use of relay switching ( Baton Handover ), which is a kind of hard switching and soft switching between a switching mode. TDSCDMA is also one of the core technologies in mobile munication 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 information 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 field petition 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 switching method. According to the TDSDMA 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 notified to all Node B measured in a mobile station signal level, whereas in TDSCDMA, 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 direction very quickly, measuring time delay and work 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 signal strength measurement delay in switching area. ( 4) relay switching and soft switching, is aimed at with the original munity maintain munication at the same time, and will switch to the munity to establish a connection. But in order to reduce the switching time, its judgments than soft 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. Therefore, in the TDSCDMA, 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 allocation WCDMA channel allocation is relatively simple, in the same frequency channel allocation in the same order system. But in the TDSCDMA system, using dynamic channel assignment ( DCA ) method, system in any one physical channel is through its carrier frequency / time / spread spectrum code bination to tag. Channel assignment is actually a radio resource allocation 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 the work load and interference changes etc.. The drawback is that, DCA algorithm is pared to FCA ( fixed channel allocation ) is more plex, 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, and 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 interference measurement of DCA algorithm, this algorithm according to the mobile station feedback realtime 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 work plann
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