MIL-STD-187-721 Interoperability And Performance Standard For Advanced Adaptive Hf RadioThe purpose of this document is to describe the technical parameters for adaptive high frequency HF radio that are more advanced than those described in MIL-STD-188-141. The advanced technology contained in this standard will guide the planning of military adaptive HF radio network technology into the 21st century. To fully understand and utilize this document, it is necessary to refer to portions of MIL-STD-188-141.

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MIL-STD-187-721D

5.  DETAILED REQUIREMENTS

5.1  Linking protection. See MIL-STD-181-141.

5.2  Time exchange protocols. See MIL-STD-188-141.

5.3  Channel and frequency designators. See MIL-STD-188-141.

5.4  Link quality functions.

The central data structure for the link quality functions is the LQA matrix in MIL-STD-188-141, the figure on connectivity and LQA memory.

5.4.1  LQA matrix.

This is an array of link quality records, each containing bi-directional measurements for (at least) BER, SINAD, and multipath (MP), and each tagged with the ages of the measurements.  The matrix is conceptually organized as a two-dimensional array, indexed by channel number and by directly reachable station (i.e., matrix contains an entry for the potential quality of a link to each station that can be called directly on every channel defined for reaching that station).

5.4.2  Sounding.

Sounding is the periodic broadcast of a station's address, so that other stations can evaluate the quality of the frequency carrying the sound for future link establishment to the sounding station.

5.4.2.1  Sounding intervals.

The required rate of sounding is determined by how busy the intended recipients are, and the maximum acceptable probability that the most recent sounds received from some stations are older than some maximum acceptable age.  For example, if B is the probability that a receiver is busy when a sound is sent, A is the maximum acceptable age (in hours), and P is the maximum acceptable probability that an entry is older than that age, then R sounds will be sent per hour, where:

R       log P  .

A log B

A and P are chosen by the network manager to satisfy network performance goals.  B is measured from actual network operation.  Specifically, B is the fraction of time during a measurement

period that the observed radio is not able to receive sounds; this usually means the fraction of time that the radio is not scanning.  Note that B includes both traffic and overhead (e.g., sounding and

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