User's Manual

18/70 Issue 01 - April 2001 - Draft 03 3CC12425AAAA TQ BJA 01
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2.3.3 – Capacity
The system capacity depends on the traffic mix between data services (transported on ATM cells) and
leased lines or telephony services (transported on TDM circuits)
It also depends on the channeling and the number of upstream channels.
Figures are given in the following tables for three mix examples : minimum, medium and maximum
circuit capacity but any intermediate mix is possible.
28 / 7 MHz channeling:
Upstream
Channel bandwidth 3.5 MHz 7 MHz
Occupied bandwidth 3.36 MHz 6.72 MHz
Roll-off factor 25% 25%
Modulation D-QPSK D-QPSK
Gross bit rate 5.38 Mbit/s 10.75 Mbit/s
Outer Code Reed-Solomon (63,53,5) Reed-Solomon (63,53,5)
Bit rate before coding 4.19 Mbit/s 8.38 Mbit/s
Radio 25 GHz 28 GHz 25 GHz 28 GHz
TS output power (antenna port) 14 dBm 14 dBm 14 dBm 14 dBm
Transmit antenna gain 35 dB 34.5 dB 35 dB 34.5 dB
Receive antenna gain (with radome) 15 dB 15 dB 15 dB 15 dB
Downlink: 28 MHz
Trafic MIX: circuit capacity
Uplink: 1 x 7 MHz Minimum Medium Maximum
Nb of circuits: 64 kbit/s 0 60 120
ATM uplink capacity (cells/s) 18.823 9.412 0
ATM downlink capacity
(cells/s)
75.512 66.530 57.399
Downlink : 28 MHz
Trafic MIX: circuit capacity
Uplink : 2 x 7 MHz Minimum Medium Maximum
Nb of circuits: 64 kbit/s 0 120 240
ATM uplink capacity (cells/s) 37.647 18.823 0
ATM downlink capacity
(cells/s)
75.512 57.548 39.286