QDOG you have made several strong assertions over the last couple of days which I dont understand. Perhaps you could explain.
You said CDMA is not the technology of choice for broadband wireless. Evidence is to the contrary. In that ERICY, NTT , and the ITU appear ready to adopt CDMA as the next generation broadband wireless technology. QCOM has indicated that CDMA2000 will offer 2mbs datrate which will be more than adequate for internet, full motion video etc.
You also said cellular and PCS are LOS. Anyone who has heard annoying cellphone ringers in theaters knows that cannot be true.
In the conventional lingo of the industry, Cellular and PCS are not considered LOS. I don't care how many modems qdog has made, or how many MIT professors he has made look stupid -- qdog is not using the term correctly.
LOS literally means that you can see one communication point from the other -- that you could hit one point with a beam of light originating from the other. Cellular and pcs systems violate this description as a matter of course.
As far as the preferred technology for broadband, the answer is it depends.
For fixed point-to-point broadband at very high data rates using directional antennas at both ends -- the traditional MMDS model -- the benefits of CDMA are not compelling. CDMA just adds cost.
When you change that to a mobile or quasi-mobile environment, add the desire to use non-directional antennas, a medium-high data rate and point to multipoint configuration -- any of the 3G CDMA systems are far superior.
gdog, my text book tells me that the free space path loss of an RF signal varies with the square of the frequency. That is, twice the frequency gives you four times the path loss. The reflection coefficient of an RF signal, which is related to the signals ability to penetrate physical objects, also varies with frequency.
So a 2.4GHz would have 2/3 more path loss than a 1.9GHz signal. It would also have a higher reflection coef.
I would think these attributes would make it, at the very least, preferable to use the lower frequency bands. Any chance that is why they selected these frequencies for cellular in the first place?
Yes, you can always put a base station next to every house. The point is to provide coverage with the minimum number of base stations. |
