STANDARD:

MIL-STD-188-141D

Overview

MIL-STD-188-141D establishes technical performance and interface parameter requirements as well as optional design directives neccesary for interoperability and standardisation of new radio systems.

The Second Generation (2G) ALE wavform, signal structures, protocols and performance requirements are described in Appendix A of the standard.

Appendix C of the standard contains the requirements for #G ALE HF radio fechnology, including automatic link maintencance and high-performance data link protocols.

Fourth Generation (4G) ALE / WALE waveforms, signal structures, protocols and performance requirements are described in Appendix G & H of MIL-STD-188-141D

2G ALE Waveform

Appendix A of the MIL-STD-188-141D standard specifies the Second Generation Automatic Link Establishment (2G ALE) waveform – physical layer and protocols. The 2G ALE waveform is still widely deployed and an important capability for backwards compatibility for systems with multi-channel capability.

The ALE 2G Waveform functionality includes the capability to detect the presence of certain waveforms occupying a given channel in the scan list. This capability is referred to as Occupancy Detection and Listen-before-Transmit. The MIL-STD-188-141D Appendix A 2G ALE signal detection implementations include the capability to detect the presence of MIL-STD-188-110 A, MIL-STD-188-110 B and MIL-STD-188-110 C, STANAG 4285, STANAG 4529.

Status	Waveform Description	Max. Rate [bps]	B/W [Hz]	Use	Standardisation
in use	2G ALE	125	3 000	LSU, AMD, DTM	MIL-STD-188-141D (2G ALE)

Table 1: 2G ALE Waveform

3G ALE Waveforms

The 3G ALE waveform has the significant advantage in that it can link in channels with SNR of -12 dB (6 dB lower than 2G ALE). This waveform also has a formal traffic management function and a very efficient set of packet data modems (xDL protocols).

ALE 4G Waveforms

The 4G ALE (WALE) system uses waveforms derived from the WB waveforms for its transmissions, and draws ideas from both 2G ALE and 3G ALE for its protocols. The WALE waveforms operate in 3 kHz and provide two modes for sending Protocol Data Units (PDUs) – the “Fast” WALE waveform (intended for very fast link setup in voicequality channels) and the “Deep” WALE waveform (designed for operation in the most challenging channels, including SNR < 0 dB).

The choice between Fast or Deep WALE can be made on a call-bycall basis as receivers listen to both types of WALE calls, as well as 2G ALE and 3G ALE calls for simultaneous operation with existing narrowband circuits.

4G ALE / WALE

ALE 4G Waveforms:
- Excellent performance in degraded HF channels by means of robust burst waveforms
- Deep and Fast Link set-up waveforms
- BW1, BW2, BW3, BW4, BW5, BW6 and BW7 according to STANAG 4538
- Doppler lock and track (capture range up to +/- 100 Hz, configurable)
- Adaptive multi-path tracking (up to 10 ms spread, for FLSU & LDL)
- Linking probability performance 2-3dB better than MIL-STD-188-141C specification
- Concurrent operation with other RapidM waveforms
Scanning
- Asynchronous (100+ ms)
- Synchronous (450 ms, 675 ms, or 1350 ms)
- Staring (optional) needs transceiver support (TBC Codan)
Automatic Channel Selection
- Channel Occupancy Table
- Link Quality Table
Occupancy Detection
- Up to 48 kHz wide
Link Setup
- One-Way Broadcast
- One-Way Link Quality Analysis
- One-Way Text Message
- One-Way Data Message
- One-Way Point-To-Multipoint
- One-Way Point-To-Point
- One-Way Time-Of-Day
- Two-Way Fill (optional, not implemented) (TBC PZ)
- Two-Way Link Quality Analysis
- Two-Way Point-To-Multipoint
- Two-Way Point-To-Point
- Two-Way Time-Of-Day
Traffic Setup
- Analog Voice
- Mil-Std 110 Appendix C
- STANAG 4415
- STANAG 4539
- STANAG 5069
Messaging
- Text, Data
Link Protection - Appendix H
- Using HALFLOOP cipher
Interoperability
- With 3G ALE
Staring (Optional - Not Supported)

4G ALE / WALE MIL-STD-188-141D Appendix G & H features