A1-6 Minimum ship e.i.r.p. vs. elevation angle Ship elevation angle Ship antenna gain Minimum ship e.i.r.p. with 6 W transmitter degrees dBi dBW 0 3 10.8 10 3 10.8 20 2.5 10.3 30 1 8.8 40 0 7.8 50 −1.5 6.3 60 −3 4.8 70 −4 3.8 80 −10 −2.2 90 −20 −12.2 3.9 Transmitter requirements for VDES ship stations 3.9.1 Transmitter power Table A1-7 defines the requirements for the VDES ship station transmitters. A1-7 Transmitter parameters mobile station Transmitter parameters Requirements Condition Frequency error 3 ppm normal Transmit power Transmit average power should be at least 1 watt and not exceed 25 watts as declared by the manufacturer. ±1.5 dB normal, +2/−6 dB extreme Conducted Maximum adjacent power levels for 25 kHz channel 0 dBc −25 dBc −60 dBc Δfc < ±12.5 kHz ±12.5 kHz < Δfc < ±25 kHz ±25 kHz < Δfc < ±75 kHz Maximum adjacent power levels for 50 kHz channel 0 dBc −25 dBc −60 dBc Δfc < ±25 kHz ±25 kHz < Δfc < ±50 kHz ±50 kHz< Δfc < ±100 kHz Maximum adjacent levels for 100 kHz channel 0 dBc −25 dBc −60 dBc Δfc < ±50 kHz ±50 kHz < Δfc < ±100 kHz ±100 kHz < Δfc < ±150 kHz Spurious emissions −36 dBm −30 dBm 9 kHz to 1 GHz 1 GHz to 4 GHz 3.10 Shutdown procedure An automatic transmitter hardware shutdown procedure and indication should be provided in case a transmitter continues to transmit for more than 2 s. This shutdown procedure should be independent of software control.
TABLE A2-9 Modified packet bit structure for satellite uplink ASM message with SCTDMA Slot composition Bits Notes Carrier sense period 56 Not transmitting (2 917 µs, equivalent to 56 bits) Ramp up 16 Standard Pre training sequence 44 0011 (repeat for 44 bits) Training sequence 27 Standard Signal information 7 Decoded from Hamming (7,4) 0000 – not coding 0001 – 1/2 coding 0010 – 3/4 coding 0011 – 5/6 coding Data length 10 Default: “0011000110” (198) encoded data and CRC; Data field 166 Without encoding:166 bits With encoding: varies according to coding rate defined in the Signal Information field CRC 32 Without encoding: 32 bits; With encoding: varies according to coding rate defined in the Signal Information Only the data length and data field are included in the CRC Long-range ASM receiving system buffer 154 Synch jitter (mobile station) = 6 bits Synch jitter (mobile/satellite) = 2 bits Propagation time delay difference = 144 bits Spare = 2 bits Total 512 Maximum 512 bits for 19.2 π/4 QPSK 6.2 Transmitting the satellite uplink broadcast message The satellite uplink ASM broadcast message should be transmitted only on ASM channels and not on the following channels: 75, 76, AIS 1, AIS 2 or regional channels. 3 Technical characteristics of VDE-terrestrial in the maritime mobile band 1 Introduction This describes the characteristics of the terrestrial VDES. It contains a description of the different protocols according to the OSI layer model and recommends implementation details for each layer. Data transmission is made in the VHF maritime mobile band. Data transmissions are made within the spectrum allocated for the VDE1-A and VDE1- B. The spectrum may be used as 25 kHz, 50 kHz or 100 kHz channels. The system should use TDMA techniques in a synchronized manner.
Channel fading bandwidth 3 Hz Target frame error rate 1 % Pilot and data duration of burst 2 371 ms Pilot duration 237.1 ms Data duration 2 133.9 ms Number of info bits 20 480 bits Number of coded bits 81 920 bits Block interleaver width 256 bits interleaver height 320 bits Interleaver size 81 920 bits Number of info bytes 2 560 bytes 2.7.3 PL-Frame format 3 The PL-Frame format 3 is provided in Table A4-14. A4-14 PL-Frame format 3 Downlink format 3 Function High throughput TDM channel File segment transfer Header 03 hex Channel bandwidth 50 kHz Unfaded C/N0 50.0 dBHz Burst duration 90 slots Burst duration 2 400 ms Ramp down 0.3 ms Guard time 8.0 ms Channel rate 19.2 Spreading factor 1 Modulation 8PSK Channel bits/symbol 3 FEC rate 0.50 FEC Type 3GPP Annex 1 Information rate/user 28.80 kbits/s Number of simultaneous 1 Eb/N0 5.4 dB Channel Rice factor (C/M) 10 dB Channel fading bandwidth 3 Hz Target frame error rate 1 % Pilot and data duration of burst 2 371 ms
Satellite ID The ID of this satellite in a network. Up to 256 satellites per network. 3 1 Bulletin version Version number of this Bulletin Up to 256 frames active 3 1 Validity of this version Lifetime of this version in number of 1 minute frames. 16 bits used. 4 1 Future satellite status change Packet providing information about planned future status change. From Julian day of year start, frame no, today and frame, new status. 13 1 Back-up bulletin board frequency Channel number above 156 MHz, 25 kHz resolution 3 1 Satellite protocol capability Index showing which protocols are supported by this satellite 3 1 Downlink channel configuration Packet providing centre frequency, start slot, PL-Frame format no, logical channel number 6 1 8 bits are used for slots corresponding to actual slot number/10. A may contain multiple announcement channels to reduce protocol latency Downlink data channel configuration Packet providing centre frequency, start slot , PL-Frame format no, logical channel number 6 1 A frame may contain multiple data channels Uplink random access/signalling channel configuration Packet providing centre frequency, start slot , PL-Frame format no, logical channel number 6 1 A frame may contain multiple uplink signalling channels to reduce protocol latency Uplink demand assign channel configuration Packet providing centre frequency, start slot , PL-Frame format no, logical channel number 6 1 A frame may contain multiple data channels This satellite ephemeris Packet containing the ephemeris, validity 25 Flexible GPS almanac format may be used. Other satellite ephemeris Packet containing network ID, satellite ID, status , ephemeris, validity 46 Flexible GPS almanac format may be used. Free text message Containing up to 128 ASCII characters 9 Flexible Network operator message to all ships, information only