The tiny Isle of Man in the Irish Sea is not known as a vanguard of technology, but this month it was to serve as the test bed f

admin2016-04-23  42

问题     The tiny Isle of Man in the Irish Sea is not known as a vanguard of technology, but this month it was to serve as the test bed for the highly acclaimed third-generation mobile phones. A subsidiary of British Telecom (BT), the British phone company, cobbled together a network and prepared to hand out prototype mobile handsets to about 200 volunteers. But problems arose in the software that keeps track of each call as it moves from one tower’s range to another’s. BT postponed the trial until late summer, after a similar delay announced a few weeks earlier by NTT DoCoMo in Japan.
    What’s the big deal? Aren’t thousands of mobile calls "handed off" every day from one "cell" to another without a glitch? They are indeed. But third-generation technology, or 3G, is so radically new that it requires a rethinking of just about every aspect of how mobile phones work, from the handset to the transmission masts to the software that runs them. For this reason, 3G are a massive engineering and construction project that will take years to complete and cost hundreds of billions of dollars. The magnitude of this effort has somehow been forgotten in the mad scramble to be first out.
    The handover problem is a case in point. When you talk on a conventional mobile phone, your call is beamed as a continuous stream of digital data to the nearest receiver. The technology for handing these calls off from one area to the next was worked out years ago. But a 3G phone is different it bundle up the data into little packets and sends them through the airwaves, one at a time. This creates the impression of an Internet connection’s being " always on," which is good news. But keeping rack of these data bundles from one region to the next is a daunting engineering problem — and, more to the point, a brand-new one. NEC, the Japanese phone company that supplies BT with equipment for its Isle of Man trail, hasn’t had time to work it out.
    Handset makers also have work to do. The 3G technologies have so many features; only a wonder gizmo could handle all of them, which is why none exists. The phones are not only supposed to work with 3G networks but also with the less sophisticated (but cheaper and more useful) General Packet Radio Service (GPRS) technology already being installed on the continent and also with the current mobile phone standard, Global System for Mobile (GSM). Phones for corporate executives are also supposed to adapt to dozens of other standards around the world. Doing all this requires powerful, custom-built computer chips, which are tough to make quickly.
    A device that does so many things is bound to guzzle a lot of power. Prototype 3G phones drain so much juice that they’ve been known to get uncomfortably hot. Batteries that can keep a conventional phone running for days would fizzle in a 3G handset in a matter of minutes. Engineers are searching for alternative, but at the moment the lack of a long-lasting battery is a major hurdle.
    None of these problems is insurmountable, but neither will they be resolved quickly. Analysts at Forrester Research in the Netherlands predict that even in 2005, when more than half of Europe’s phones will be connected to the Internet, fewer than 15 percent of them will use 3G. That’s a measure of this technology’s complexity and immaturity.

选项

答案 男人岛,这个爱尔兰海上的小岛,并不是以技术先锋而知名,但这个月它将成为广受赞扬的第三代移动电话系统的测试基地。隶属于英国电信公司的英国电话公司已匆匆搭建了一个网络,并准备将该手机的样机发放给大约200名志愿者。但是负责监控发射塔之间通话传递的软件出了问题,英国电信公司将实验推迟到了夏末。几周之前,日本的NTT DoCoMo也宣布推迟类似的实验。 这算什么大事?每天不都有上千的移动电话在不同的发射覆盖范围出现类似的小毛病吗?确实是这样。但是第三代的技术,或者所谓的3G,是全新的技术,它需要我们重新思考移动电话运作的各个方面,包括手机,发射天线和运行的软件等。正是由于这个原因,3G是一个巨大的工程和建设项目,需要花费几年的时间和成百上千亿的资金来完成。在争夺谁最先胜出的混战中,大家似乎都已经忘记了所需的这些巨大付出。 信号转换问题就是个很好的例子。当使用传统的移动电话时,通话是作为连续的数字信号被发送到最近的接收塔的。把信号从一个地区向另一个地区传送的技术在许多年前就已经解决了。但是3G电话不同,它把这些信号压缩成一个个的数据包,通过空中电波逐个发送。它给人的印象好像互联网的联结一样,永远在线。这当然是个好消息。但是从一个地区到另一个地区之间持续地跟踪这些数据包却是个异常困难的课题,或者更确切地说,是个全新的课题。为英国电话公司在男人岛的实验提供设备的日本NEC公司目前仍没有找到解决问题的办法。 手机制造商也有许多问题要解决。3G技术可以提供众多的功能,目前还没有一家公司能够生产出一个非凡的产品把所有功能都包括进去。这样的手机不但要适应3G的网络。还应能适应已经在欧洲大陆使用的相对简单,有效而便宜的GPRS技术以及现有的移动电话标准系统——GSM系统。供公司高级主管使用的手机还要能适应全球的其他数十个标准系统。满足这样的要求需要功能强大的,按要求定制的计算机芯片,这很难在短期内完成。 能够提供这些功能的设备注定会消耗大量能量。现在的3G样机能量消耗过大,致使机身过热,使用者感到不舒服。传统手机可使用几天的电池,在3G手机上用几分钟就没电了。工程师们正在寻找替代办法。目前没有能够长期使用的电池是个主要的障碍。 所有这些问题都不是不能解决的,但都不可能很快解决。荷兰Forrester研究公司的分析家预言,到2005年,超过一半的欧洲手机用户都可以同互联网相接。即使如此。也只有不到15%的用户使用3G手机,这能衡量出此项技术的复杂和不成熟。

解析
转载请注明原文地址:https://jikaoti.com/ti/cqcYFFFM
0

相关试题推荐
最新回复(0)