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In the United States, Verizon and MetroPCS have LTE networks, and AT&T and Sprint have also announced expansion or interest in this technology. Garnering an additional nod, low-frequency (700 mhz) LTE has recently been endorsed by the U.S. for public safety and disaster recovery use.
Even though it’s still new, LTE is all the buzz these days, making significant headlines at Mobile World Congress in Barcelona. Joss Gillet, Senior Analyst for Wireless Intelligence, outlined the global LTE roadmap:
“2011 marks the beginning of LTE rollouts worldwide…Europe will lead in terms of network deployments with 31 operators expected to commercially launch LTE by year-end, compared to nine in Asia Pacific and six in North America.”
While the theoretical speed limit of LTE in its current incarnation is 50 Mbps, real-world tests say 12 Mbps is the real upper speed limit, and many users experience far slower speeds.
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"Future iterations of LTE and Wi-MAX will become the first true 4G technologies." |
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space than there will be in WiMAX…so
LTE will predominate, but WiMAX still
has a place in the more price-conscious
or emerging marketplaces.”
Where is the Real 4G?
So we see that in actuality, none of the networks marketed as 4G are actually capable of delivering 4G speeds as defined by ITU; in fact, in real-world, not theoretical situations, some so-called 4G networks don’t deliver much beyond 3G speeds.
In terms of speed, networks currently marketed as “4G” are more precisely 3.5G. In terms of technological evolution, as we’ll see below, ITU allows LTE and WiMAX networks to be labeled “4G” because they are not backwards compatible to 3G and their future iterations will meet the 4G standard.
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WiMAX:
WiMAX stands for “Worldwide Interoperability for Microwave Access.” WiMAX boasts theoretical speeds up to 40 Mbps download, while real-world testing produces a more sobering 6-12 Mbps. Future iterations of WiMAX will meet the ITU definition of 4G, and have a theoretical downlink speed 28% higher than LTE-Advanced. Sprint/Clear uses WiMAX technology for its 4G network.
WiMAX has been around much longer than LTE, it costs significantly less to deploy than LTE, and enjoys greater popularity in developing countries where carriers have less capital outlay in legacy networks.
There are many WiMAX dongles and
hubs on the market, however, there
are significantly less WiMAX phones on
the market vs. LTE, and these devices,
in general, drive the market. John Kim,
VP of Business Development at Alepo,
explained the device dilemma: “Devices
drive consumers, consumers want
sleek and sexy devices, and there are
more device manufacturers in the LTE
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Differences between 4G and 3G
Despite the confusion regarding 4G speeds, there are significant differences in the underlying technologies. The main difference in all iterations is that 4G radios use Orthogonal Frequency-Division Multiple Access (OFDMA) communication protocol instead of CDMA. OFDMA offers better interference management, increased spectral efficiency, increased number of users, and inherently less complexity. Another key difference is that 4G is an all-IP packet switched network, versus a combination of circuit-switching for voice and IP-packet switching for data.
There are many more differences between the two standards, but the above two make the two technologies incompatible. In other words, you need an LTE phone to work on an LTE network, and connecting and LTE or WiMAX phone to 3G networks requires a handover. This is significant, because that fancy new 4G phone may be spending as much or more time on a 3G network, at least in the year to come.
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