mighty, regarding spectral efficiency. there are many issues with this presentation in regard to spectral efficiency:
A) it is a spectral efficiency comparison test for VOICE only
B) the test represents a symmetry of the up and downlinks.
As for (A), FUTURE revenue generation for WCDMA, and for that matter CDMA2000, is dependent more on the efficient transmission of data, i.e. multi-media applications, not necessarily voice. Voice is easily quantifiable for CDMA2000 in terms of both performance and revenue generation. Spectral efficiency for data within WCDMA in an asyncronous or unpaired mode far exceeds any current format out there.
And for (B), since CDMA2000 uses a symmetrical path for both up and downlinks, efficiency can be easily determined. But in an evironment where huge data bursts on a download (such as internet) are constantly occurring, the WCDMA format offers greater opportunities in unpaired or asymmetrical up and downlinks.
The opportunities are found especially in time division duplexing (TDD) of data, within the WCDMA model, wherein the uplink and downlink can be fitted to precisely fit the flow of data.
Even as the site claims:
...In summary, chip rate is not a simple issue with a direct cause and effect relationship. More is not necessarily better. cdma2000 enables 3G services without the deployment risks and cost of WCDMA.
More efficiency for "voice" is not necessarily better for a revenue generation model for Operators who are betting their 3g revenue future on "data" transmissions.
Even so, Nokia has claimed that "efficiency" arguments for comparing voice transmissions of a CDMA2000 model with that of a WCDMA model are flawed because they do not compare similar technologies: that is compare a Nokia model with a CDMA2000 model. I would take this to mean that Nokia believes they can achieve equal or superior spectral efficiency on all fronts including voice. |
