Arnie:
If the above numbers are correct, that means that NXTL has the POTENTIAL to have as much capacity as T and more than FON! So the only question is "Are the numbers correct, both in theory and math?
Spint PCS (FON) uses CDMA so the comparison doesn't apply. The numbers are basically correct.
However, as I answered Paul, you don't get something for nothing. When I responded to Tony I said he should also discuss what the reduced bandwidth per voice channel means for relative voice quality.
iDEN, D-AMPS and PCS-1900 are all digital. All transform our voices into bits for transmission. The more bits you have to represent a slice of sound, the more accurate is its replication.
Lets assume that all three systems can transmit 1 bits per hertz. (this is illustrative, I don't have the numbers handy anymore). Therefore, a 30 khz channel would have a total payload of 30,000 bits and a 25 khz channel has only 25,000 bits. Divide that by three and you see how much "payload" each voice channel has. To make a long story short, the fewer the bits, the less accuracy of sound reproduction, all things being equal. Also, fewer bits generally translates into greater susceptibility to interference, again all other factors being equal.
Since Direct Connect is 6:1, does that increase NXTL's capacity beyond the above calculations?
Yes, but not in the same way. A typical voice call grabs a channel and dedicates it for the duration of the call, i.e., radio link from the mobile to the base and the base to the mobile are dedicated to the call. With direct connect, the radio link from the mobile to the base is dedicated when you "push to talk." When you release the button, that link is freed. When the other party talks to you, the radio link from the cell site to your phone is dedicated and later released. If all radio channels at a cell site were direct connect, then and only then would you get 6:1 increase, provided that the inbound talking exactly matched outbound talking.
The actual increase in site capacity is dependent on the ratio of DC channels to regular channels and the ration between inbound and outbound. Without Nextel's actually traffic statistics, I could not begin to estimate what the capacity improvement is.
hope this helps
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