Nortel Networks 411-2021-111 manual Cell Site Layouts, Omni cell site configuration

3-1

Cell Site Layouts

This chapter provides information on the layout and cabling of the different DualMode Metrocell configurations.

Important

For ALL Metrocell cell site configurations, the frequency plan used should have a minimum of 21 channel spacing (630 kHz) between the channels in one RF Frame.

Note: The DualMode Metrocell supports only Transmit Receive Units (TRU) with Product Engineering Code (PEC) NTAX98AA. No other radios can be used. The NTAX98AA TRU supports full digital and analog transmissions in accordance with IS-54 and IS-41 standards.

Omni cell site configuration

The Metrocell in an omni configuration uses at least two equipment frames, one CE Frame and one RF frame (see Figure 3-1). With only one RF frame, the maximum number of Voice Channels (VCH) supported by the cell site is 22 since two of the 24 TRUs have to be assigned as the Control Channel (CCH) and the Locate Channel Receiver (LCR). As traffic grows, four additional RF frames can be added to the site to accommodate up to a maximum of 120 channels, including the CCH and the LCR.

An RF Frame with up to 20 channels requires only one duplexer in the RF Frame and one TX/RX antenna. The outputs of the three AutoTune Combiners (ATC) are combined through one phasing transformer (located at ATC 2) and then connected to Duplexer position 2. This configuration requires a RX only antenna for the diversity receive function of the cell. See Figure 3-2.

An RF Frame with 21 channels or more requires two duplexers in the RF Frame and two TX/RX antennas. The outputs of the lower and middle ATCs

DMS-MTX DualMode Metrocell Cell Site Description