Specifications

1
Radio Port (RP) B1990
RP Functions
The RP provides the link between Subscriber Unit (SU) and Radio Port Control Unit
(RPCU).
Extremely compact and lightweight, Syncomm's RP is economical to purchase and can
be installed outdoors for excellent coverage. The following are basic RP functions:
n Link between SU and RPCU
Whether in making a phone call or receiving an alerting message, the user's
SU communicates with the wireline network element (RPCU) through the RP
which functions as a RF modem over the air interface.
n Transmission/reception of radio signals
Each RP transmitter takes a framed and encoded signal from the modulator
and converts it to the appropriate carrier frequency. The RP transmitter then
transmits a π/4 DQPSK(Differentially encoded Quadrature Phase Shift Keying)
signal with a TDM radio channel structure out to the SUs. The uplink TDMA
bursts are transmitted by the SUs arrive at the RP, where the TDMA signals are
amplified, translated in frequency, demodulated, diversity combined,
synchronized, decoded, and converted to a TDM line interface signal for
transmission to the RPCU.
n Channel coding/decoding for error detection and burst synchronization
The burst is synchronized between RP and SU. Error detection is employed
to mitigate the errors induced during transmission. Because the entire burst is
only 120 bits long, synchronization and error detection processes are combined.
Placing the burst encoding/decoding circuitry at the RP helps to minimize the
RP-to-RPCU transmission requirements.
n Synchronization
The local reference clock at the RP will extract the timing from the
transmission wireline facility (e.g., HDSL) to synchronize itself to the network
and may reference all transmit and receive frequencies to the same oscillator, that
is, to maintain the stability of transmit and receive frequencies.
n Termination of air interface
Message sets, measurement and performance monitoring data, signaling
information and operations data are combined with the 384Kbps RF channel data
to make up the transmission facility (e.g., HDSL).
n Mapping of radio channel bit rate(384kbps) to standard HDSL line rate
The radio channel bit stream is mapped into a HDSL line rate by bit stuffing,
and then the unchannelized HDSL signal is transported over a wireline network
facility to the RPCU. The purpose is to provide a standard physical level line
interface.