28 October 2015

STANAG-4538 BW5 sample

waveform BW5

The usual 2G scenario (MIL 188-141 2G-ALE + MIL 188-110A/B 3KHz serial-tone) is replicated here but using 3G waveforms: the sample shows a data transfer, using one of the MIL 188-110C App.D serial-tone waveforms (precisely the waveform-id n.7 15KHz bandwidth, seen in another post), followed by STANAG 4538 FLSU 3G-ALE signal to supposedly close the link. 
To avoid confusions, MIL 188-141C Appendix C third-generation ALE is termed Link Set-Up (LSU) in STANAG 4538. Two non-interoperable protocols for link establishment are specified in STANAG 4538: Fast LSU (FLSU, smaller, lightly-loaded tactical networks) and Robust LSU (RLSU, large networks and heavy traffic).  The specifications previously contained in the Appendix C have been replaced with reference to the essentially identical NATO STANAG 4538: I refer to this document.

The ALE segments have been downsampled and decimated in order to get a better signal to analyze (pic. 2), so it was possible to identify the 3G-ALE as the Fast LSU burst-waveform n.5, or BW5 waveform as indicated in the table shown in picture 3, just from the standard STANG 4538. PSK-8 modulation is analyzed in pic. 4.

Pic. 2 - 3G-ALE signals after downsampling
lenght of the burst: 1013 ms
Pic. 3 - the heard signal mathces the characteristics of the BW5 waveform
Pic. 4

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