US 4,780,885 AGranted

Frequency management system

OwnerHaim D. Paul, Joseph M. Perlinventors

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Abstract

A high frequency (HF) frequency-management system for automatically selecting optimum HF frequency. A frequency management means controls the operation of a regular HF radio communications transmitter and receiver at each station. The frequency-management means transmits sounding signals synchronously and repeatedly over a finite group of HF frequencies, from a first radio communications station to a second radio communications station. Link quality evaluation (LQE) is carried out at the second station. Sounding signals are transmitted synchronously and repeatedly back to the first station. Optimum HF frequencies are selected based on the sounding signals and LQE. An HF communications path is automatically established between stations. The system performs the scanning of the HF frequencies, the detection and measurement of signals, noise and interferences on each frequency and the timing synchronization as required for the frequency management operation.

Claims18

Dependent claims

A high frequency (HF) frequency-management system that performs automatic selection of the optimum HF frequency for reliable communications between two or more stations of an HF net and dissemination of the optimum frequency, for the automatic establishment of HF communications path between two or more radio stations of the said net, comprising of a frequency management means that controls the operation of a regular HF radio communications transmitter and receiver at each stations;

the said frequency-management means comprising means for transmitting sounding signals synchronously and repeatedly over a finite group of HF frequencies, from a first radio communications station to a second radio communications station;
means for link quality evaluation (LQE) at the second station;
means for transmitting back sounding signals, synchronously and repeatedly over said finite group of HF frequencies, from said second station back to said first station;
means for selecting optimum HF frequencies at the said first station, based on said sounding signals and LQE;
means for dissemination of said optimum HF frequencies information, by the said first station to the said second station (and all other stations in the net), for the automatic establishment of an HF communications path between said stations, wherein said first and second stations utlize said regular HF radio communications transmitter and receiver for both the frequency management functions as well as for the usual communication function, in time interleaved mode controlled by the said frequency management means;
and means for monitoring the noise and interferences on said finite group of HF frequencies, means for searching for incoming communication or sounding calls;
means for performing the timing and control of the HF radios;
means for acquiring and maintaining synchronization of the frequency management system and communication net;
and each said means performing the scanning of the HF frequencies, the detection and measurement of signals, noise and interferences on each frequency and the timing synchronization as required for the frequency management operation.

6 more elements

A method of selecting an optimum HF frequency for reliable communication between two or more stations of an HF net and for disseminating the optimum frequency, establishing automatically an HF communication path between two or more stations of said net, which comprises the steps of controlling the operation of a regular HF communications transmitter and receiver at each station, transmitting sounding signals synchronously and repeatedly over a finite group of HF frequencies, from a first radio communications station to a second radio communications station, continuously monitoring the interference and occupancy of a finite group of HF channels, each channel a different frequency;

hard-labeling each one of the said channels as either a binary "1" for a `quiet` channel or a binary "0" for a `noisy` channel, based on a predetermined set of criteria;
storing and updating the resulting set of binary labels wherein each bit represents an evaluation of one of the HF frequencies visited;
using this binary word as a sounding signal and transmitting this signal repeatedly, once over each of the said finite group of frequencies by having the transmitter scan said channels;
synchronizing said second station receiver so that it is sequenced through same said group of channels at an equal rate, being at each one of the channels at the same period of the time as the transmitter, to allow the sounding message to be received;
majority-detecting said redundant sounding message by the receiver;
performing link quality measurements on each of the scanned group of frequencies;
hard-labeling each one of the said channels as either binary "1" for a "good" or "acceptable", and a binary "0" for a "bad" or "not-acceptable" communication quality, based on another set of criteria;
storing the resulting set of binary labels to be used by it in forming the answer-back sounding signal from said second station to said first station;
transmitting the answer-back sounding message repeatedly, once over each of the said group of channels by having said second station transmitter scan said channels;
majority-detecting said answer-back sounding message by the first station receiver, performing link quality measurements by the first station receiver, on each one of the said scanned group of frequencies;
selecting optimal frequencies by the first station, for reliable communications in both directions, based on the analysis of the received and locally evaluated link quality patterns;
utilizing the synchronization maintained between the stations, to disseminate the selected frequencies information to said second station;
automatically tuning the communications transmitters and receivers to the selected preferred frequencies, thus establishing reliable communication paths between the stations.

10 more elements

Dependencies are inferred from the claim text.