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NTT DoCoMo's 4G Tests Hit 300Mbps
haunebu writes "'Your brand-spankin'-new 3G phone is nearing obsolesence: NTT DoCoMo reveals the results from a new 4G test system.' says TheFeature. While in a car moving at 30kph, DoCoMo engineers managed a peak throughput of 300Mbps and a sustained transfer rate of 135Mbps with their new variable spreading factor orthogonal frequency code division multiplexing (WSF-OFCDM) downstream technology. Who comes up with these names, and how does Japan manage to stay lightyears ahead of everyone else in wireless?"
Who comes up with these names...
Assuming the poster is referring to ``variable spreading factor orthogonal frequency code division multiplexing (WSF-OFCDM) downstream technology'', the name describes exactly how the technology works. Without reading a technical paper on the technology, I don't know the exact details, but I know what it is doing and what it isn't doing.
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how does Japan manage to stay lightyears ahead of everyone else in wireless?
Might have something to do with the fact that they have 130 Million people in an area slightly smaller than california.
Lot less area to provide coverage for. Not to mention 26 million people in Tokyo alone, making it the highest density city on the planet.
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...that it's a very small island, just put big transmitters on mountantops and you're good to go
Actually this is not funny. The United States is, for the most part, sparsely populated compared to most of Europe and Asia. This is why the U.S. carriers hesitated to adopt GSM in the early 90s, which has a fixed number of supported users/frequency and has a maximum cell size due to being time multiplexed. On the other hand, CDMA is able to create much larger cells at the expense of a higher noise floor (hence less users). It was promised to be better suited to sparsely populated areas, yet still tuneable to suit New York City and etc. Whether or not CDMA IS-95 met those goals is debateable.
Japan is indeed under less contraints. Their cell sizes are very small meaning the required transmission power is reduced. If anybody ever saw a Japanese PDC phone from 10 years ago, and was blown away at how small it was, this is the explanation.
It would be nice to mention that before the furor erupts...
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Motorola's GSM base stations offer extended range cells (120km radius) which do implement the coverage density/cell size tradeoff you describe. I'd imagine it might be easier for CDMA to offer a larger set of grades than these do, though.
NTT is a surprisingly large company (now a group of companies), and the bureaucracy of such a company is staggeringly prohibitive to actually getting anything accomplished.
We tried launching Wireless access there in 2000 and 2001, and the endless meetings and forms were more than discouraging.
But the real answer to how NTT DoCoMo (a division of the monster) manages to turn around so fast is that their researchers work with cell researchers from KDDI, J-Phone (now Vodafone), and that other one who nobody uses (TUCA).
Where does all the funding for research come from? Well, in a country of now 135 million people, there are over 80 million cellular subscribers. A good portion of these are also cellular internet users, paying an extra 100 yen here, 100 yen there for different services.
There is a LOT more income on a monthly basis to Japanese cellular providers than there is in America, or anywhere else in the world.
The easy bottom line is that all this cash can be thrown at research, and that this research is further supported by companies like National/Panasonic, Toshiba, Sony, etc who make the phones for Japan.
The average turn-around time in phone ownership in Japan is 9 months. Your $150 top-of-the-line video-camera/mp3/digital still camera/phone is made obsolete in that short span of time. The furthering of technology by DoCoMo/Vodaphone/etc allows the phone manufacturers to move more units.
The consumer gets new features at the same monthly price (more or less), a new phone to show off to friends, and better service.
The providers and hardware manufacturers rake in the cash.
The cycle supports itself, and it makes everyone happy.
Only those who attempt the absurd will achieve the impossible.
yeah - AC has a point (perhaps 2) here.
The Japanese were fairly brutal during the war.
They killed maybe more than hilter and Stalin - mostly east asians, chinese and Koreans
Nasty.
My Bad
Hmm. Perhaps you should consider the technology name. Much like the old quadrature based encodings, the orthogonal nature of the encoding will permit multiple bits per cycle. Othogonal carriers would be independent of one another, and therefore, be something that could be sampled independently.
Do not confuse what Nyquist has to say about sampling a single signal with the numbers presented. Each orthogonal component is a new axis upon which they can mux a data carrier (in the simplest sense).