美国：移动信号哪里最差？

如今，各大主流运营商都拿出了百十亿美元的资金推广各自的4G网络，但全美各地的推进程度却并不均衡。

网络评级机构Rootmetrics公司进行的调查显示，美国各大城市的4G网络的普及有很大差距，因为运营商的投资与某些地区的用户增长率并不总能保持同步。在该公司最近发布的排名中，包括芝加哥、亚特兰大和纽约在内的一些大城市的排名都有所下降。

为测试全美各地的移动网络建设情况，Rootmetrics公司派遣了一批专业测试人员，驱车分赴美国的125个主要城市，对当地移动网络的总体可靠性、网速以及通话、短信息和数据质量等指标进行测试，然后根据测试结果，对美国四大主流运营商——AT&T、威瑞森、T-Mobile和斯普林特进行了排名。其中，威瑞森在最近的这张榜单上排名首位。

2016年下半年，美国网络质量居首的五个城市全部集中在远离东西海岸的中部地区。其中印第安纳波利斯以抢眼的总体网速和数据网络性能排名首位，里士满以较强的可靠性和通话服务排名第二，排在第三位的克里夫兰也有较强的网速和数据性能。排名第四的哥伦布市在各项指标上都比较均衡。明尼阿波里斯市在这张榜单上名列第五位。

在倒数前五名中，奥马哈在所有125座城市中排名倒数第一。奥马哈地区的居民忍受着全美最差的移动网络服务，这座城市在每个指标上都排名垫底。尤其是较高的通话阻断率已经成为这座城市移动网络服务的最大问题。这已经是奥马哈连续第三次在调查中排名垫底或倒数第二名了。

沃斯特市的移动网络质量排名倒数第二，它的邻居斯普林菲尔德则排在倒数第四名。倒数第三是加州的圣罗莎，倒数第五则是纽约地区的哈德孙谷。

Rootmetrics公司也指出，对于纽约市北部的居民来说，他们所能享受到的网络质量还是较之前的几次调查稍有提高。“与上一轮测试相比，哈德孙谷地区的消费者的确在2016年下半年享受到了更好的移动网络体验，它在五大指标类别上的总分都有所提高。”

在美国人口最多的大城市中，纽约的总体移动网络质量排名全美第66位，洛杉矶排在第49位，迈阿密排在第89位，费城排在第32位。排名第8的芝加哥则是特大城市中唯一进入前十的一个。（财富中文网）

作者：Aaron Pressman

译者：朴成奎

Mobile carriers have spent billions to expand the reach of their 4G networks, but the gains aren't spreading evenly across the country.

Surveys by network rater Rootmetrics found starkly varying conditions in different metropolitan areas, as carriers' investments didn't always match the growth of usage in some places. In its latest rankings, some of the largest cities in the country—including Chicago, Atlanta, and New York—saw their ratings drop.

Rootmetrics sends professional surveyors driving through 125 cities to test mobile networks on overall reliability and speed, as well as separate measures of call, text, and data quality. The firm rates the big four carriers—AT&T (t, -1.02%), Verizon (vz, -0.90%), T-Mobile (tmus, +1.28%), and Sprint (s, -0.12%)—in a separate report. Verizon came out on top most recently.

For the second half of 2016, the top five cities ranked by overall network quality were all in the center of the country away from the coasts. Indianapolis garnered the top spot, thanks to strong overall speed and data networking performance. Number two-ranked Richmond earned its place with strong reliability and calling ratings. Cleveland was third, also with strong speed and data performance, while Columbus was fourth with steady scores across all categories. Minneapolis rounded out the top five.

Among the five bottom dwellers, Omaha was ranked last out of all 125 metro areas, Rootmetrics said. Omaha residents received the worst mobile performance in the country, with the city ranking dead last in every category tested. A particularly high rate of blocked calls was the city's biggest issue. It was the third straight survey where Omaha ranked last or second to last.

Just slightly better, Worcester's mobile networks ranked second last in the survey, with nearby Springfield, Mass., ranking fourth worst. In between, Santa Rosa, Calif., ranked third worst. And the final member of the bottom dwelling five was the Hudson Valley, N.Y. region.

Still, for residents of the area north of New York City, performance improved slightly from previous surveys, Rootmetrics noted. "Compared to the previous round of testing, consumers in Hudson Valley did enjoy a better mobile experience in the second half of 2016, with higher composite scores in all five performance categories," the testing firm wrote.

Among the five largest cities by population, New York ranked 66th in overall mobile performance, Los Angeles was 49th, Miami was 89th, and Philadelphia was 32nd. Only residents of Chicago, which ranked 8th overall, made the top 10 of the rankings.