Nortel Networks 411-2021-111 manual Stsr cell site connection, Sector U, Sector W

Cell Site Layouts 3-21

60° STSR cell site connection

The Metrocell in a 60° STSR configuration uses at least three equipment frames, one CE Frame and two RF frames (see Figure 3-8). Each TRU/DPA Shelf and its associated ATC on one of the two RF frames support one of the six sectors. With only two RF frames, the maximum number of Voice Channels (VCH) supported by each sector is six since two of the eight TRUs on the TRU shelf have to be assigned as the Control Channel (CCH) and the Locate Channel Receiver (LCR). A 60° STSR Metrocell with two RF Frames requires twelve antennas; one TX/RX antenna and one RX only antenna for each sector (see Figure 3-10). As traffic grows, two additional RF frames can be added to accommodate more VCHs per sector (see Figure 3-9).

A 60° STSR Metrocell with four RF Frames has 16 channels for one sector (including the CCH and the LCR) and each sector requires two TRU/DPA shelves and two ATCs. It also requires twelve antennas; one TX/RX antenna and one RX only antenna for each sector. The outputs of the two ATCs for each sector are combined through one phasing transformer and connected to a duplexer. The output of duplexer is then connected to the main TX/RX Antenna of that sector. The diversity RX antenna of each sector is connected directly to the Receive Multicoupler (RMC) of that sector. Figure 3-9 shows the frame layout and Figure 3-11 shows the block diagram of a 60° STSR Metrocell with four RF Frames.

Control Channel redundancy

Control Channel (CCH) redundancy is commonly provided with a Locate Channel Receiver (LCR) backup. With two RF Frames, the CCH of each sector is assigned to position 1 on the TRU/DPA Shelf of that sector and the LCR is assigned to position 4 on the same shelf. With four RF Frames, a typical assignment of the CCH and LCR for each sector is listed below:

	Control Channel	Locate Channel Receiver
Sector X	RF Frame 1/TRU Shelf 1/Position 1	RF Frame 1/TRU Shelf 1/Position 4
Sector Y	RF Frame 2/TRU Shelf 1/Position 1	RF Frame 2/TRU Shelf 1/Position 4
Sector Z	RF Frame 2/TRU Shelf 3/Position 1	RF Frame 2/TRU Shelf 3/Position 4
Sector U	RF Frame 3/TRU Shelf 1/Position 1	RF Frame 3/TRU Shelf 1/Position 4
Sector V	RF Frame 4/TRU Shelf 1/Position 1	RF Frame 4/TRU Shelf 1/Position 4
Sector W	RF Frame 3/TRU Shelf 3/Position 1	RF Frame 3/TRU Shelf 3/Position 4

This arrangement will have the CCH and the LCR supplied on a different DC power feed and a TCM card. No RF coaxial switch is required since the cavity of the LCR position on the ATC will tune to the CCH frequency when backup is required.

DMS-MTX DualMode Metrocell Cell Site Description