【4G is one of those terms that keep coming back through marketing brochures for what the latest technologies happen to be in the

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问题 【4G is one of those terms that keep coming back through marketing brochures for what the latest technologies happen to be in the cellphone market.Every carrier claims to have true 4G,and has been claiming that for years,regardless of what they actually use.The reason was simple because the real 4G specification,expected to be drafted by the International Telecommunication Union,was no where to be found.In fact,the ITU took way longer than being expected to come up with a decision,likely because of massive lobbying campaigns.After all,which company wants to have to redesign its entire network just to be able to keep saying they are 4G?Now however,the ITU has decided itself.What does this mean for carriers and users?  First,let’s see what 4G really is.As expected.LTE is central to the ITU strategy,but more precisely,the organization went with LTE.Advanced.Which is a stricter version of traditional LTE.To qualify as 4G,a network has to provide 100 Mbps connections over wireless,and 1 Gbps over wired.The whole network has to be fully IPv6 compliant.Frequencies have to be scalable over 40 MHz to avoid interference.Finally, global roaming has to be seamless,along with transitions between wireless and wired connections.
This is a real step forward,and a good decision,which ensures that real 4G services will meet a good level of service.Technically,LTE—Advanced is just one of two new standards that are now under the umbrella called IMT-Advanced.The other one is WiMAX 2 which is a further refinement of the WiMAX protoco1.】
Based on the paragraph above,to qualify as 4G,a network has to satisfy(98) criteria The transitions between wireless and wired connections have to be(99).LTE-Advanced is a standard belonging to(100).
(100)

选项 A、WiMAX
B、WiMAX 2
C、IPv6
D、IMT-Advanced

答案D

解析 本题考查4G方面的基本知识。
4G技术是营销手册众多条款中的一条,说明了运营商在手机市场上所采用的最新技术。多年以来,每一个运营商都一直声称拥有真正的4G,而不管的实际使用情况如何。原因很简单,因为真正的由国际电信联盟起草的4G标准,还没有正式出台。事实上,因为大量的游说活动,国际电联将比预期需要更长的时间来完成这项任务。毕竟,重新设计整个网络就能够说他们的公司实现了4G吗?然而现在,ITU自己决定了这件事情。这对运营商和用户意味着什么?首先,让我们看看什么是真正的4G。正如预期的那样,LTE是ITu的战略中心,但更准确地说,组织了LTE-Advanced,这是一个比传统的LTE更严格的版本。为了满足4G的需求,网络需要提供100 Mbps的无线连接,1 Gbps的有线连接。整个网络可以完全兼容IPv6。为了避免干扰,频率可扩展性超过40兆赫兹。最后,随着无线和有线连接之间的转换,全球漫游必须是无缝的。这是一个真正的进步和好的决定,以确保真正的4G服务将满足良好的服务水平。从技术上讲,IMT-Advanced包括两个新的标准,一个是LTE—Advanced,另一个是WiMAX2,它是WiMAX协议的进一步改进。
基于以上,必须满足五个标准,网络才有资格成为4G。无线和有线连接之间的转换是无缝的。LTE-Advanced是属于IMT-Advanced标准。
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