Caxton,
In case you didn't read the Adventis Report,here's what it has to say about HDR:
"In principle HDR enables a maximum data rate of 2.4 Mbps over a 1.25 MHz channel. However, these speeds are only possible at SHORT ranges (less than 5% of a cell under IDEAL conditions), and averaged over a typical cell a theoretical maximum of 600 kbps is more likely (Qualcomm).
These rates are, however, based on LAB CONDITIONS and published expectations of average data rates are closer to 200 kbps.
{Footnote: As the number of users INCREASES, average data rates for HDR may be as low as 33 kbps downstream and 11 kbps upstream for a reasonable number of active users of
15-20 per sector, or 4.5-6 per square mile (1XHDR)Airlink Overview, Qualcomm, Inc. April 28,2000, Revision 3.1;IEEE}
What I gather from this is that every company can boast "theoretical maximums" or "burst speeds," but the bottom line is what kind of performance can one expect on a loaded system, under normal operating conditions? This is the real test.
Qualcomm, by their own admission, has admitted here that with a system containing 4.5-6 users per square mile the average data rate for HDR may be "as low as 33kbps." Straight from the horses mouth, who will dispute this?
4 1/2 to 6 users per square mile isn't very many. What happens if there are 10 users per square mile? Lower speeds obviously. The system apparently does NOT have the same ability as MCDN to "scale."
Regards,
Charlie R. |
