I don't know anything about the technical details related to the studies upon which those graphs were based on, but I do know that when a company/organization wants to do so, it can get quite creative when it comes to playing with tests, studies, and benchmarks so as to suit their own strategic/financial ends. I've seen EMC do this to Network Appliance, and Network Appliance return the favor. I've seen Intel discredit AMD in this manner, and Tom's Hardware discredit Intel the same way.
What I've read so far has suggested that while using wider frequency spreads for a given wireless technology leads to increasing processing/battery power requirements for a given terminal, it also allows for more network capacity. Even Gilder, although generally critical of W-CDMA, said something similar:
Message 14557674
In theory WCDMA enhances the advantages of CDMA by expanding fourfold the spread (or so called "chipping rate") in its "spread spectrum." Thus, each signal is spread more widely by a higher chipping rate, each bit is lower power, rendering the resulting background noise even more Gaussian (a smoother more random appearing hum against which to search out the signal). Since more users are sharing a single channel, the statistical multiplexing advantages of variable rate vocoding are enhanced.
The law of large numbers, however, suggests that at some point "large" becomes "too large" and returns beyond this point diminish. Before settling on a 1.25 MHz spread almost a decade ago, Qualcomm sage Klein Gilhousen studied a range of spectrum widths and chipping rates for expanding the signal. He found that an eightfold increase, from a chipping rate of 16 to 128, produced a 20 percentage point increase in spectral efficiency. By increasing the rate another eightfold to 1024 over 10 MHz, however, the WCDMA proposal of the time would yield less than half that increase, about 9 percent. The current WCDMA proposal would yield about 6 percent greater spectral efficiency.
And I should also remind you that the W-CDMA can be overlayed over existing GSM networks; cdma2000 doesn't have that advantage, thus making it more expensive. 1xEV/HDR would provide more capacity and a somewhat smoother upgrade...if wireless networks ran nothing but IP for voice as well as data. VoIPoWireless hasn't advanced that far yet for this to be completely feasible. There have to be major upgrades not only to the wireless networks, but also to the general-purpose optical backbones upon which the traffic would go through. Maybe in three or for years it'll be a different story.
Of course, by then, most major GSM/PDC carriers will have W-CDMA up and running, and they won't want to put their money into another, completely new technology for another five years. But this tangent's covered as well by the push for "enhanced" W-CDMA:
eetimes.com
Jan Uddenfeldt, chief technology officer for Ericsson (Stockholm), said the work on enhancing W-CDMA will occur in tandem with the CDMA2000 1xEV effort to take the U.S. version of CDMA up to 2 Mbits/s...Phase one of W-CDMA is generally considered to be the immediate introduction of basic 3G service, while phase two is the move to fully Internet Protocol-based transport, including such developments as voice-over-IP.
So, as you see, there's a very good chance that there will eventually be an HDR-like technology deployed on these networks, with all the capacity/data rate benefits that would come with it; but if/when it happens, it'll probably be done via a far more sensible upgrade path for the carriers that are being targeted.
As I once said before, with a couple of exceptions, the announcements made so far by carriers regarding the 3G platforms that they're opting for come across as fairly reasonable given the circumstances that surround them. Most current CDMAone carriers are going for cdma2000, and most current GSM carriers are going for W-CDMA. Meanwhile, HDR's being looked at by the cdma2000 side for future IP-centric networks, and a technology with specifications that will most likely incorporate many of the attributes of HDR is being studied by the W-CDMA group for a similar purpose.
I have to agree that this industry does have its share of absurdities when it comes to the strategic decisions made by those who run it, perhaps far more so than, say, the optical networking or storage industries. However, IMO, it still doesn't act anywhere as irrationally as some may think. |
