Atenção: Considere o texto abaixo para responder às questões de números 56 a 60.
London becomes 4G high speed internet hotspot
London will begin to switch on 4G high-speed mobile internet with the launch of the first large-scale public trial in Britain. Initiated by O2, Britain's second largest operator with 22 million customers, the trial involves more than 25 masts covering 15 square miles. It will run for nine months, and the equipment installed will eventually become part of O2's first commercial 4G network.
The technology is 10 times faster at navigating the internet than the current 3G networks, which often frustrate smartphone users because they are significantly slower than the average home broadband connection. The 25 masts in London will be able to carry more data than O2's entire national 3G network.
Britain's 4G or long-term evolution (LTE) upgrade, expected to begin in earnest in 2013 after a much delayed spectrum auction, will make mobile networks powerful enough to handle video calls, high definition TV and live multi-player gaming. About 1,000 users will be invited to join the London trial.
Initially, the O2 trial will not involve phones, because no compatible handsets exist yet. Samsung dongles will be handed out to plug into tablets and laptop computers, as will portable miniature modems that can create small WI-FI hotspots linking into O2's 4G infrastructure or "backhaul".
The new technology is capable of speeds of up to 150 megabits per second. During the trial, users will be more likely to experience average speeds between 25Mbps and 50Mbps. When 4G is introduced nationally the average speeds are likely to drop to between 10Mbps and 15Mbps. This is faster than 3G, which averages between 1Mbps and 1.5Mbps, and compares well with the average household, fixed line broadband connection, which rose to just under 7Mbps this year.
Live gaming against other players and video calling without delays will become possible from phones, because the speed at which new information loads onto the screen will be reduced from 1 second to 0.07 seconds.
(Adapted from www.guardian.co.uk, Sunday 13, November, 2011)
During the trial phase, the speed of the 4G network is estimated to be