In telecommunication

Telecommunication

Telecommunication is the transmission of information over significant distances to communicate. In earlier times, telecommunications involved the use of visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, and optical heliographs, or audio messages via coded...

, automatic sounding is the testing of selected channels for quality by providing a very brief identifying transmission that may be used by other stations to evaluate connectivity, and availability

Availability

In telecommunications and reliability theory, the term availability has the following meanings:* The degree to which a system, subsystem, or equipment is in a specified operable and committable state at the start of a mission, when the mission is called for at an unknown, i.e., a random, time...

, and to identify known working channels for immediate or later use for communications

Telecommunication

Telecommunication is the transmission of information over significant distances to communicate. In earlier times, telecommunications involved the use of visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, and optical heliographs, or audio messages via coded...

 or calling. Often used to maintain connectivity

Telecommunication circuit

A telecommunication circuit is any line, conductor, or other conduit by which information is transmitted.A dedicated circuit, private circuit, or leased line is a line that is dedicated to only one use...

 in digital communications high frequency radio

Shortwave

Shortwave radio refers to the upper MF and all of the HF portion of the radio spectrum, between 1,800–30,000 kHz. Shortwave radio received its name because the wavelengths in this band are shorter than 200 m which marked the original upper limit of the medium frequency band first used...

 networks.

Automatic soundings are primarily intended to increase the efficiency of the automatic link establishment

Automatic link establishment

Automatic Link Establishment, commonly known as ALE, is the worldwide de facto standard for digitally initiating and sustaining HF radio communications. ALE is a feature in an HF communications radio transceiver system, that enables the radio station to make contact, or initiate a circuit, between...

 (ALE) function, thereby increasing system throughput

Throughput

In communication networks, such as Ethernet or packet radio, throughput or network throughput is the average rate of successful message delivery over a communication channel. This data may be delivered over a physical or logical link, or pass through a certain network node...

.

In ALE, the sounding information consists of a heavily error-corrected

Forward error correction

In telecommunication, information theory, and coding theory, forward error correction or channel coding is a technique used for controlling errors in data transmission over unreliable or noisy communication channels....

 short message identifying the sender. Recipients decode it and use the bit error rate to calculate and store a (channel, node, quality) tuple

Row (database)

In the context of a relational database, a row—also called a record or tuple—represents a single, implicitly structured data item in a table. In simple terms, a database table can be thought of as consisting of rows and columns or fields...

. As ionospheric conditions and mobile-node locations change, these quality tuples will shift. The stored data can be used to maximize the chance that the best channel to link with a given partner will be chosen first.