Nortel Networks 411-2021-111 manual Control Channel redundancy, RF Frame

3-2Cell Site Layouts

(ATC 1 and ATC 2) are combined through one phasing transformer (located at ATC 2) and then connected to Duplexer position 2 and the main TX/RX Antenna. The output of the upper ATC (ATC 3) is connected to Duplexer position 3 and the diversity TX/RX Antenna. This arrangement is used to meet the requirement of a minimum of 21 channel spacing (630 kHz) between the channels in one RF Frame. This configuration requires a TX/RX antenna to perform the diversity receive function of the cell. See Figure 3-3.

Control Channel redundancy

Control Channel (CCH) redundancy is commonly provided with a Locate Channel Receiver (LCR) backup. The CCH is assigned to position 1 on the TRU/DPA Shelf 1 and the LCR is assigned to position 4 on the same shelf. 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.

Figure 3-1

Frame layout of an omni Metrocell with one RF frame (front view)

CE Frame

CE RIP

DRUM

ACU

HSMO

CSM2

RMC 1

Blank Panel

ICRM

Blank Panel

Base

RF Frame 1

RF RIP

Duplexer Duplexer Duplexer

Position 3 Position 2 Position 1

		ATC 3
21	22	DPA	DPA		23	24
17TRU	18TRU				19TRU	20TRU	TRU/DPA
		11		12
TRU	TRU	DPA	DPA		TRU	TRU	Shelf 3
		9		10
		ATC 2
13	14	DPA	DPA		15	16
TRU9TRU	10TRUTRU				11TRUTRU	12TRUTRU
		7		8			TRU/DPA
		DPA	DPA				Shelf 2
		5		6
		ATC 1
5	6	DPA		DPA	7	8
TRU	TRU				TRU	TRU	TRU/DPA
		3		4
							Shelf 1
1	2	DPA		DPA	3	4
TRU	TRU	1		2	TRU	TRU

Base

Note: For a frame with up to 20 channels, only one duplexer (located in position 2) is required.

For a frame with 21 channels or more, two duplexers (located in positions 2 and 3) are required.

411-2021-111 Standard 01.01 June 1996