ADCP-75-210 • Issue 1 • March 2007
Page 2
© 2007, ADC Telecommunications, Inc.
1.2 System Function
The NXD Distributed Antenna System (DAS), in which the RAN is the remote component, is a
multi-frequency, multi-protocol RF access network providing microcellular Cellular and PCS
coverage via a distributed RF access system. In a typical configuration, such as shown in
Figure 2, multiple RANs are connected to a central Hub where multiple Base Transceiver
Station (BTS) interfaces are located. Signals received at the Hub are distributed to the RANs in
digital form by way of a fiber optical link. Within the RANs, the signals are converted from
digital to RF format to be transmitted from the RAN antennas. Signals also travel in a reverse
direction, from the RANs to the Hub, with a reverse data conversion.
Physically, the DAS consists primarily of electronic modules located in the Hub and RANs. At
the Hub, these modules are mounted in an equipment rack typically housed in a common
telecommunications structure with the base station electronics for Wireless Service Providers
(WSPs), either in the same room or nearby. These modules include high power attenuators, base
station modules, a power distribution unit, an Ethernet hub, a Hub reference module, an RF
chassis, and one or more digital chassis. The RAN electronic modules, mounted in the RAN
cabinet, perform the remote system functions of optical to RF data conversion and RF access.
These modules are described in subsequent topics within this product description. Digivance
Element Management System (EMS) software, running on a computer located at the Hub,
provides a graphical user interface to monitor system performance.
Figure 2. System Function
BTS BTS BTS BTS
Distribution Hub - EMS Server,
located on Hub Master, monitors
Hub Nodes and RANs
Digital
Fiber
Radio
Access
Node
21013-A
RF
SIGNALS
WIRELESS
SERVICE
PROVIDERS
(WSPs)
