User Manual

AS4000 Wireless Local Loop
System Overview
GSI 001
605-0000-430
Issue 1.2 Date 7/4/99
Page 11 of 16
8.3 Subscriber Terminal ISDN (ST- I1)
8.3.1 The Subscriber Interface
The Subscriber interface is an “S” Basic Rate Interface (2B+D) at the customer premises,
i.e. NT1 functionality. This interface is according to ITU-T (CCITT) I.420/421 {ETS 300
012, 300 125 and 300 102-1}, and provides a short passive bus connection at the
Subscriber Terminal. This passive bus supports up to eight I420 ‘S’ interface compatible
devices. See Figure 9
AC
PSU
Subscriber Terminal
(ST-I1)
CRU
Junction
Box
NT1
(RJ45)
Terminal
Adapter
Drop
Cable
TE2 Terminal
TE1 ISDN Terminal
‘S’ Passive Bus
Supports up to 8 devices)
~
Figure 9. Subscriber Terminal ST-I1
8.4 Frequency Planning
Figure 10 shows the current AS4000 frequency plans.
The deployment of AS4000 will depend upon the requirements for coverage. When
deployed over a wide area Central Terminals will be deployed using a reuse pattern of three.
This means that all twelve channels required for a wide area deployment as shown in Figure
11 below will be used in three adjacent cells.
The use of a three cell pattern is shown in Figure 11. The 12 frequency channels allocated
from the frequency spectrum shown in Figure 10 are distributed over a cluster of three cells
in the most efficient way to ensure minimum interference.