Overview For A Gtr 8000 Base Radio In Conventional Architectures; Figure 4: Gtr 8000 Base Radios In Hpd Remote Site - Motorola ASTRO 25 GTR 8000 Manual

MN003286A01-E
Chapter 1: GTR 8000 Base Radio Description
The HPD base radio provides a full-duplex RF interface to HPD Mobile Subscriber Units (MSUs). The
HPD base radios are available for 25 kHz HPD operation in the 700 MHz or 800 MHz bands. Up to five
HPD base radios may be installed at the site. Each base radio has an Ethernet connection to both of
the site controller modules at the site.
The HPD base radio uses Radio Link Adaptation (RLA) to provide high-speed, reliable, enhanced data
performance when communicating traffic with MSUs. RLA uses adaptive modulation techniques, with
slower, and more reliable modulation for control signaling and retries, and faster modulation methods
when traffic is successfully being delivered between the base radio and MSUs.
The HPD base radio is implemented with 2X receiver diversity. This receiver diversity enhances the
inbound signals from the MSUs on the channel.

Figure 4: GTR 8000 Base Radios in HPD Remote Site

The HPD base radio uses Time Division Multiplex (TDM) frames for random access channels,
reserved access channels, and broadcast messages. All carriers in the system are synchronized by a
Global Positioning System (GPS) so that transmission slots are synchronized across sites. The base
radio is able to schedule inbound/outbound traffic for half-duplex MSUs so that outbound traffic
intended for the MSU does not conflict with inbound random or reserved access traffic from the MSU.
1.8
Overview for a GTR 8000 Base Radio in Conventional
Architectures
Throughout this manual, the term "conventional" addresses either an analog only base radio or an
ASTRO ® 25 Conventional base radio that operates in either digital mode or mixed (analog/digital)
mode. Conventional base radios operate within:
• An analog only infrastructure
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