MIL-STD-188-110B
Overview
MIL-STD-188-110B describes the technical standards and design objectives for narrowband HF data modems. The standard describes minimum requirements for Frequency Shift Keying (FSK) and HF serial (single-tone) and parallel tone modem waveforms. This version of the standard is identical to the previous version, with the addition of Appendices C, D, E & F.
Status
The second revision of the MIL-STD-188-110 “Military Standard Interoperability and Performance Standards for Data Modems” was released in April 2000. It has since been superseded by later revisions, the current one being MIL-STD-188-110D (December 2017).
Key Features
- Legacy MS110A modes provide FSK data rates up to 1200 bps, and PTM data rates up to 2400 bps in a 3 kHz channel as required for backwards interoperability with legacy voice and data systems.
- Autobaud capable Single Sideband (SSB) STM waveforms providing data rates ranging from 75 to 9600 bps coded, and 12800 bps uncoded, in a 3 kHz channel. Specifically, Appendix C of the MIL-STD 188-110B standard specifies the HF Data Modem Waveforms for data rates above 2400 bps.
- Autobaud capable Independent Sideband (ISB) STM waveforms providing data rates ranging from 9600 bps to 19200 bps in a multi-channel (2-ISB, USB 3 kHz and LSB 3 kHz). Specifically, Appendix F of the MIL-STD-188-110B standard is an early design for wideband serial-tone modems and has been widely implemented in naval systems in an attempt to achieve higher data rates.
Relevance
- Serial tone autobaud capable PSK waveforms providing data rates up to 9600 bps are widely used in modern data Automatic Repeat Request (ARQ) data systems.
- The NATO STANAG 4539 specification specifying the HF Data Modems for data rates 75 to 9600 bps, includes the waveforms and associated data rates of the MIL-STD-188-110B standard.
- The combination of SSB and ISB serial tone autobaud capable PSK waveforms is widely deployed in networks using both SSB and ISB-cable radios. RapidM modems can autobaud on the 9600 bps data waveform (as per Appendix C and Appendix F) whether it has been transmitted from a SSB or ISB radio.
Serial Tone Mode (STM) – Single Sideband
The table below summarises the complete MIL-STD 188-110B SSB STM waveform suite. Included in the table are the modulation, code rate and interleaver settings for each data rate. The lower data rates include a tone excision capability to supress narrowband interferers. The inclusion of tone excision improves the waveform resilience and performance in the presence of channel interference.
| Waveform | Data Rate (bps) | Modulation Constellation | Coding Rate | Interleaver Settings | Tone Excision Capability |
|---|---|---|---|---|---|
| MS 110B & MS 110B-C | 75 C | Walsh | 1/2 | Z, S, L | YES |
| 150 C | BPSK | 1/8 | YES | ||
| 300 C | BPSK | 1/4 | YES | ||
| 600 C | BPSK | 1/2 | YES | ||
| 1200 C | QPSK | 1/2 | YES | ||
| 2400 C | 8-PSK | 1/2 | YES | ||
| 2400 C VOICE | 8-PSK | 1/2 | Z, S | YES | |
| 3200 C | QPSK | 3/4 | US, VS, S, M, L, VL | NO | |
| 4800 U | 8-PSK | None | None | YES | |
| 4800 C | 8-PSK | 3/4 | US, VS, S, M, L, VL | NO | |
| 6400 C | 16-QAM | 3/4 | NO | ||
| 8000 C | 32-QAM | 3/4 | NO | ||
| 9600 C | 64-QAM | 3/4 | NO | ||
| 12800 U | 64-QAM | None | None | NO |
Table 1: MIL-STD-188-110B & MIL-STD-188-110B Appendix C – STM Waveform Suite
The figure below illustrates the Bit Error Rate (BER) performances of the MIL-STD 188-110B STM (SSB Modes) waveform suite as measured for ITU-R Poor Channels. The RapidM RS8 Wideband HF & V/UHF Channel Simulator was used to simulate the HF channel conditions.
Figure 1: Bit Error Rate (BER) Performance of MIL-STD-188-110B (SSB Modes) for ITU-R Poor Channels
Serial Tone Mode (STM) – Independent Sideband
The table below summarises the complete MIL-STD 188-110B Appendix F STM waveform suite, providing the autobaud modem waveforms with data rates from 9600 to 19200 bps coded in an ISB (USB 3 kHz and LSB 3 kHz) channel.
| Waveform | Data Rate (bps) | Modulation Constellation | Coding Rate | Interleaver Settings | Tone Excision Capability |
| MS 110B-F (2-ISB) | 9600 C | 8-PSK | 3/4 | US, VS, S, M, L, VL (same as 110B Appendix C Interleaver definition) | NO |
| 12800 C | 16-QAM | 3/4 | NO | ||
| 16000 C | 32-QAM | 3/4 | NO | ||
| 19200 C | 64-QAM | 3/4 | NO |
Table 2: MIL-STD-188-110B Appendix F – STM Waveform Suite
The figure below illustrates the Bit Error Rate (BER) performances of the MIL-STD 188-110B STM (SSB and ISB Modes) waveform suite as measured for ITU-R poor channels. The RapidM RS8 HF and V/UHF Channel Simulator was used to simulate the HF channel conditions.
Figure 2: Bit Error Rate (BER) Performance of MIL-STD-188-110B (SSB & ISB Modes) for ITU-R Poor Channels
Use of MIL-STD-188-110B (SSB and ISB Modes)
SSB versus ISB data modem selection
- The 4800 bps waveform used in MS110B (SSB) is based on an 8-PSK signal constellation used as the data modem waveform modulated in either the LSB or USB sidebands.
- The 9600 bps waveform used in MS110B (SSB) is based on a 64-QAM signal constellation used as the data modem waveform modulated in either the LSB or USB sidebands.
- The 9600 bps waveform used in MS110B-F (ISB) is based on an 8-PSK signal constellation (similar to 4800 bps in MS110B) used as the data modem waveform modulated in both the LSB or USB sidebands.
- In theory, the performance of the 9600 bps MS110B-F data modem should be similar to that of the 4800 bps MS110B waveform. This is the case when the BER performance is measured by baseband channel simulators in the Lab. In practice, there is a penalty involved when actual radios are used.