Dave - Are there differences in the way the spreading/handoffs etc are to be done in WCDMA compared with CDMA2000,leaving timing issues aside?
As usual, some good points. There are a lot more differences between W-CDMA and CDMA-2000 then just chip rate and synch. Almost surely the protocols for power control, soft handoff, vocoder bit rate changing, ... are all different, and I suspect that these areas are ones in which Nokia and Motorola have had a lot of problems. Qualcomm appears to have listed all the things that made W-CDMA incompatible with CDMAOne and then prioritized them according to which would cost the most to change in an existing CDMAOne system and removed all but the top five.
Why is WCDMA called direct sequence and CDMA2000 multicarrier, as if CDMA2000 were not direct sequence?
I would speculate that it is for the same reason that W-CDMA is the acronym. Confusion between the generic and the particular. 'We're the experts in Direct Sequence CDMA' makes you think that they know more than Qualcomm about all forms of DS-CDMA, when in reality all that they are really more experienced at is the particular mode.
Isn't this just a spectrum issue which has nothing to do with synchronous/asynchronous pilots, chiprate, concatenated convoluted Solomon turbochargers and the rest? Is there any reason CDMAone can't be used in these new slices of spectrum?
The difference in spectrum used between W-CDMA and CDMA-2000 in its wide mode is very little. And CDMA-2000 in its wide mode is not multi-carrier. Just FYI.
Of course we won't know until later but perhaps the 3.8x rate is 10% more efficient and someone building an entirely new network ie NTT might be willing to take the risk with the hope of gaining that capacity.
And what about data? Is there even a kernel of truth in these factoids we've seen numerous times claiming WCDMA will do data better?
W-CDMA might indeed provide 10% more throughput due to chip rate; then again maybe not. The big argument against a different chip rate is that there are many things in the system that affect the capacity more than the slight difference in chip rate possibly could, and the system capacity uncertainty is certainly greater than the chip rate difference. To hone a particular parameter that has a few percent effect on performance which is lost in the noise is known in engineering circles as 'polishing a turd'.
As for handling data, there are few ways to know without a full simulation, but generally I would expect that if there are significant differences that most of them could be easily handled in software. Most hardware aspects are probably not factors in data transmission performance. Thus this is not likely to be a good reason for keeping a separate mode.
Clark
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