STANAG 4539

Overview:

The RapidM modems include the narrowband HF data modem waveforms, which are in compliance with STANAG 4539.  This standard describes the Serial Tone Mode (STM) providing data rates ranging from 75 to 9600 bps coded, and 12800 bps uncoded, in a 3 kHz channel.

Status:

The STANAG 4539 (Edition 1) “Technical Standards for Non-Hopping HF Communications Waveforms” was released in Jun 2005.

Key Features:

• Very robust traffic waveform providing a 75 bps autobaud data modem for conveying data traffic over severely degraded channels, as specified in STANAG 4415.
• Low to medium data rate traffic waveforms providing autobaud data modem with data rates ranging from 150 to 2400 bps coded, as specified in MIL-STD-188-110 (Section 5.3).
• High data rate traffic waveforms providing autobaud data modem with data rates ranging from 3200 to 9600 bps coded and 12800 bps uncoded. Specifically, Annex B of the STANAG 4539 standard specifies the HF Data Modem Waveforms for data rates above 2400 bps.
• Non-hopping TDMA traffic waveforms providing data modems for HF fixed frequency slotted TDMA operation. Specifically, Annex D of the STANAG 4539 standard specifies the modulation types and contents for three TDMA waveforms, namely WF1, WF2 and WF3.

Relevance:

• The single tone PSK waveforms are important for backwards interoperability with NATO BRASS systems used by Navies.

Serial Tone Mode (STM):

The table below summarises the complete STANAG 4539 waveform suite. Included in the table are the modulation, code rate and interleaver settings for each data rate. The STANAG 4539 waveform includes tone excision, whereby suppression of up to 4 tones is possible.  The inclusion of tone excision improves the waveform resilience and performance in the presence of channel interference.

Table 1: STANAG 4539 – STM Waveform Suite

The following tables give performance results for the RM modems for various data rates. The results were measured using an HF Channel Simulator.

An AWGN channel is representative of ground wave propagation, while the POOR channel represents skywave conditions. A RICEAN channel has a steady (specular) component and a fading component, thus representing a mixture of the ground and skywave propagation scenarios.

Table 2: Performance: STANAG 4539