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Transmission Modes
WAVECOM Decoder W74PC, W-PCI/e, W-CODE, W-CLOUD Manual V9.1.0
possible in a broadcast connection. A lossless compression format is used for compressing Codan-3212
data stream with arbitrarily length.
CODAN-3212 Waveform:
The modem uses a high-speed waveform to address other CODAN-3212 mo-
dems. The CODAN-3212 waveform is based on the STANAG-4539 waveform, which has been modified for
commercial use. This waveform transports data in conjunction with a STANAG-5066 protocol. The wave-
form is centered at 1500 Hz with a baudrate of 1800 symbols per second. The supported waveforms of the
modem are:
User data rate
Waveform
80 baud CHIRP
Proprietary link establishment
2400 bps
CODAN-9001/9002/3012
16 Channel QPSK
CODAN-3012
75 bps
CODAN-3212: Modified STANAG-4539 serial tone wave-
form (in conjunction with STANAG-5066 Protocol)
150 bps
300 bps
600 bps
1200 bps
2400 bps
3600 bps
4800 bps
6000 bps
7200 bps
The characteristics of the CODAN-3212 waveform are shown below:
User data rate
FEC coding rate
Interleaver
Modulation
75 bps
1/2
Short or Long
8-PSK (Walsh)
150 bps
1/8
Short or Long
8-PSK
300 bps
1/4
Short or Long
8-PSK
600 bps
1/2
Short or Long
8-PSK
1200 bps
1/2
Short, Medium or Long
8-PSK
2400 bps
3/4
Short, Medium or Long
8-PSK
3600 bps
3/4
Short, Medium or Long
8-PSK
4800 bps
3/4
Short, Medium or Long
16-QAM
6000 bps
3/4
Short, Medium or Long
32-QAM
7200 bps
3/4
Short, Medium or Long
64-QAM
CODAN-32122 Decoder:
Each transmission of a CODAN-3212 message begins with a synchronization
phase (preamble). In the preamble, the data rate and the interleaver setting are encoded.
For user data rates up to and including 1200 bps, the preamble includes 480 8-phase symbols. The pre-
amble lasts for 0.8 seconds in case of messages with a SHORT interleaver and 6.4 seconds for messages
with a LONG interleaver setting. The preamble is followed by the data phase, which is of unlimited length.
The data phase consists of an undefined number of interleaver blocks. Each interleaver block is divided in-
to user data and channel probe. The user data is of unknown phase, whereas the channel probe has a
predefined phase pattern. The probe pattern, which corresponds to the known 8-phase symbols, is regu-
larly inserted to make sure the decoder will synchronize at any time of the transmission, without having to
repeat the preamble at regular intervals.
Preamble (0.8 or 6.4
s)
Interleaver 1
Interleaver 2
Interleaver 3
...
Interleaver N
For user data rates above 1200 bps, the preamble includes 287 8-PSK symbols. The preamble is followed
by the data block of unlimited length. The data block consists of 256 symbols paired with a 31 mini-probe
pattern. After 72 user data - mini-probe pairs, a 103-symbol mini-preamble is inserted. The mini-probe
pattern and the mini-preamble are regularly inserted to make sure the decoder does not loose synchroni-
zation. The FEC and interleaver are used to reduce the effects of fading, frequency drift, multi-path effects
and burst noise in the HF transmission. At the end of the transmission, a certain bit pattern is transmitted
(in HEX: 0x4B 0x65 0xA5 0xB2) to mark the end of the message.
