>>Can somebody answer some questions for me? What is the difference between CDMA and TDMA and who uses what? Which is better and why? Which is more expensive and why?>>
Frank:
This question has been covered over and over again. Check your web resources for details or go back over this thread.
I don't have the time to give you a full answer today - and I am not a technical expert in this area, but.....
For the layman:
TDMA - Time Division Multiple Access. Packets of voice or IP data are encoded digitally and then sent across micro-slices of time slots, then reassembled at the receiving end.
CDMA - Code Division Multiple Access. The spectrum itself - versus time - is divided up into mulitple slices. Voice/IP data is encoded digitally and sent across these multiple slices of the spectrum rainbow and then reassembled at the receiving end.
Capacity argument: You can only divide "time" into so many slices. You can divide spectrum into a theorectically unlimited number of slices. They have yet to hit the boundary on splicing "time" with TDMA. With CDMA there are other issues beyond capacity that are creating problems.
Thumb Nail....
TDMA - high energy bursts, longer duration, wave amplitude, carries longer distances, fewer towers, stronger handoffs, lower capacity, lower cost of buildout.
CDMA - low energy, shorter wave amplitude, shorter distances, requires more towers, weaker handoffs between cells, more overall potential capacity, higher cost buildout.
Trying to create SMR-like DC on higher-frequency CDMA must be like trying to fit a camel through the eye of a needle. Just MHO.
As we've seen so many times in other areas, the best technology doesn't win that often. All the brightest OS technologists in the
have decried the growth of windows, but the additional hardware, CPU and RAM horses were more than ready for the task of pulling that stage coach.
The Nextel/Motorola iDEN version of TDMA should have a unique niche opportunity for some time. The i1000 has opened up a whole new market for iDEN. Cross country DC and FAST IP data will ensure the standard has legs.
All the best.
Anybody else care to chime in??? |
