User Manual

Demand Assignment
System Overview GSI 002
605-0000-450
Draft Issue 1.3dr Date 8/02/00
Page 18 of 16
STs track available TCHs to permit “fast acquisition”. When a user’s line goes “off-
hook”, STs request allocation of a TCH from the available pool. The CT instructs STs
to “seize” a particular TCH, if access noise permits.
Traffic engineering is via the management system, which allows the following
parameters to be programmed:
• Minimum / maximum number of traffic channels
• Number of access channels
• Demand access protocol type
• BER grade of service threshold
• Call blocking threshold
• Number of priority channels
7.3. Frequency Ranges Supported.
AS4000 supports system implementation in various frequency ranges within the ITU-R
and ETSI 2GHz and 3GHz frequency ranges. The specific channel plans available (see
Appendix A) operate in frequency bands at:
• 2.0-2.3GHz, in accordance with CEPT/ERC/Rec. 13-01E, Annex C, with 175MHz
duplex spacing
• 2.3-2.5GHz, in accordance with ITU-R 746, with 94MHz duplex spacing
• 3.4-3.6GHz, in accordance with CEPT/ERC/Rec. 14-03E (Turku 1996), with
100MHz duplex spacing
AS4000 operates in licensed spectrum, normally co-ordinated with other users by the
licensing authority. Coexistence with other systems is in-line with ETS EN 301 055.