do nothing iphone case

The problem is simple: There's not enough spectrum available throughout the world in the same frequencies to make roaming between networks easy or cost effective. So even though most of the world's wireless carriers will finally be operating networks using the same basic technology, they still may not allow for easy international roaming. "The fragmentation in 4G is driven by spectrum scarcity," said Neville Ray, chief technology officer for T-Mobile USA. "The International Telecommunications Union tried 15 years ago to harmonize the spectrum plan globally, but what works well for one country or region doesn't work well in another region. So we have this patchwork approach."Fragmentation is a killerA recent report published by the GSMA's Wireless Intelligence Service predicts that at least 38 different radio frequency combinations may be used in LTE deployments in the next few years. For example, operators in the U.S. are mostly using 700MHz spectrum to build their 4G LTE networks. But in parts of Europe operators are using 2.6 GHz. China is using 2.5 GHz. Japan is using 2.1 GHz. And many markets in Southeast Asia are using 1.8 GHz.

And devices built for one band of do nothing iphone case radio frequency won't work on a network that uses a different band, In other words a Verizon 4G LTE smartphone that operates on 700MHz spectrum in the U.S, will not operate on TeliaSonera's 4G LTE network in Sweden, which uses spectrum in the 1800MHz band, There are similar spectrum differences among countries when it comes to 2G and 3G networks, But what's different about the shift toward 4G is the shear number of radios that must be supported to offer roaming, When 2G and 3G spectrum was allocated, regulators in various regions of the world were able to work together to develop more comprehensive spectrum plans that necessitated fewer radios in devices..

But now spectrum in almost every part of the world is harder to come by, which means more radios must be supported in devices to allow for international roaming. Some experts in the industry say that the lack of cohesive spectrum planning has fragmented the market so much that it will be difficult and expensive for device makers and carriers to ever make roaming from one LTE network to another anywhere in the world as seamless as it is today for mobile subscribers to roam onto 3G networks. "We'll likely see some LTE roaming between different regions and carriers," said Chris Pearson, president of the industry trade group 4G Americas. "But it won't be worldwide roaming."But others are more optimistic. Dan Warren, senior technology director for the GSMA, an international trade group promoting GSM technology throughout the world, is confident that technology advancements will prevail and save the day for future LTE device-toting globe trotters.

And he believes that technology is advancing rapidly to get more radio technologies handling more frequencies into devices at a much lower cost, "What's happening in terms of the number of radio technologies that can be added to a chip is not classic Moore's Law, but it's similar" he said, "There has been a lot of change in the past 9 to 12 months, And we're seeing chipsets go from do nothing iphone case single and dual frequency to four and five frequencies."Today's so-called "world" phones already need to operate in about six bands to get access to 2G and 3G networks around the world, To include LTE roaming, wireless devices will need another six or seven frequency bands, Warren estimates, This means that the next generation of truly mobile "world" devices will need at least 12 frequency bands..

Also, spectrum at higher frequencies is not ideal for indoor coverage. The reason is that signals at higher frequencies don't propagate as easily through obstacles, such as walls. This makes high-frequency spectrum problematic for in-building coverage. Spectrum in the lower bands is scarce because it's already been allocated for other purposes. For instance, the 700MHz that U.S. operators are using for LTE was initially allocated for analog TV. The FCC was able to free up spectrum in this band when it forced TV broadcasters to broadcast in digital rather than analog back in 2009. This made more efficient use of spectrum and allowed the FCC to clear a large chunk of spectrum, which it auctioned off in 2007.