The sky is falling, communism is on the rise, Hillary Clinton
is a lesbian. Opinion or fact?
Donald C. Cox is a respectable author, who Frezza plagiarizes,
did a wonderful treatise named 'Wireless Personnal
Communications: A Perpective.' (1992) I suggest you find it
and read it. It will validate your feelings about QCOM and
CDMA. It will give you a warm and fuzzy feeling about TDMA
and IDC (although I can't recall them being mention). So far,
especially with Nortel, you choose to pick only that which
condemns CDMA. That's fine, I don't look at the world with
rose color glass's either. I'm a communications (non computer)
professional, who by necessity and curiousity, must stay abreast
of the changes in technology. One of the more amusing
claims of TDMA is 'We can get 6x to 10x if we microcell'.
What does that mean? It means if we put more base station
closer together we can realize increase in capacity.
Bernd-Peter Paris says it best, IMO: "Many comparisions in
terms of capacity between TDMA and CDMA can be found
in the recent literature. Such comparasions, however, are often
invalidated by making assumptions that favor one access
method over the other. An important exception constitutes the
recent paper by Wyner (1994). Under a simplified model
that nevertheless captures the essence of cellular systems,
he computes the Shannon capacity.
* TDMA is distinctly suboptimal in cellular systems
*When the signal-to noise is large, CDMA appears to
achieve twice the capacity of TDMA.
*Multiuser detectors are essential to realize near optimum
performance in CDMA systems.
* Intercell interference in CDMA systems has a detrimental
effect when the signal-to noise ratio is large, but it can be
exploited via diversity combining to increase capacity
when the SNR is small.
I'm not sure the date of this writing. So far Jim you quote
to me press release's and magazine articles, what I keep
offering is a broad spectrum of opinion from the scientific
community. Offer, at least to me, substantial technical study
and not company propaganda. So far I offered sites that
are pro and con. You choose to focus on the con. Continue
on, we should never be lemmings and we all should maintain
some sort of skepticism. But, for every negative about TDMA
or CDMA, I can find positives for TDMA and CDMA.
In fiber optics, the new buzz is WDMA (Wave Division Multiple
Access). There are claims of something like 6x increase with
this Voodoo technology. Being a professional, I have to continue
to investigate and evaluate the temerity of all claims and studies.
I realize this to be a stock forum, and yes, I've traded QCOM.
I'm not above taking profits when they present themselves. But,
I'm also deeply involved with the industry and that is my main
interest. That is how I stumble on to this forum, pursuing info
on CDMA.
Remember this, if it's analog and wireless I can easily
monitor your conversation. Where doesTDMA and CDMA
fall into that? Of these two which is the easier
and which is the more difficult? What is NMT? Who introduced it?
Did it succeed? These should keep you busy, but please
spare me company propaganda, pro or con. |
