User's Manual

8 System Description
Chapter 1 - System Description
Each AU-IDU includes four channels using a common PHY and MAC
that can connect to up to four outdoor radio units, according to the
selected diversity mode (refer to Section 1.2.5 below for more details).
The AU-IDU module connects to the AU-ODUs via Intermediate
Frequency (IF) cables carrying full duplex data, control and
management signals between the AU-IDU and the AU-ODU, as well as
power (-48 VDC) and 64 MHz synchronization reference clock from the
AU-IDU to the AU-ODU. The IF Tx and Rx frequencies are 240 MHz
and 140 MHz, respectively. IDU-ODU service channel at 14 MHz
serves for bi-directional control, status and management signaling.
1.2.4 AU-ODU-HP
The AU-ODU-HP (High Power ODU) is a full duplex multi-carrier radio unit that
connects to an external antenna. It is designed to provide high system gain and
interference robustness utilizing high transmit power and low noise figure.
1.2.5 Base Station Radio Configurations
The 4-Channel High-Power AU-IDUs support the following radio configurations:
1.2.5.1 Single Channel per AU, No Diversity
This is the basic configuration, where each AU-IDU connects to one ODU, serving
a single sector with a directional antenna.
1.2.5.2 Multiple Channels per AU, No Diversity
Up to 4 channels per AU-IDU can be used to cover several sectors, where each
channel connects to one ODU, with one ODU per sector. A single AU-IDU can
cover a 360° cell. Where the coverage of the cell can be built from 3 sectors of 120°
each with frequency reuse 1, or 4 sectors of 90° each with frequency reuse 1 (i.e.
frequency per sector) or 1/2 (i.e. 2 frequencies for 4 sectors where each frequency
is used for 2 opposite sectors). All ODUs served by the same AU-IDU share a
common MAC and modem. Each ODU is managed separately.