Method and System of Adaptive Communication in the HF Band

• US 20120309330A1
• Filed: 11/30/2011
• Published: 12/06/2012
• Est. Priority Date: 11/30/2010
• Status: Active Grant

• Current Assignee: Thales SA
• Original Assignee: Thales SA
• Inventors: LAMY-BERGOT, Catherine, PHILIPPE, Crambert, GILBERT, Multedo, DOMINIQUE, Merel, JEAN-FRANÇIS, Gaschi
• Granted Patent: US 9,008,594 B2
• Time in Patent Office: Days
• US Class Current: 455/101
• CPC Class Codes: H04L 5/006 Quality of the received signal, e.g. BER, SNR, water filling
• CPC Class Codes: H04L 5/06 the signals being represented by different frequencies combined with time-division multiplexing H04L5/26

Abstract

A method for adaptive communication in an HF frequency band includes at least one of the following steps: the determination of a payload subband S that is available for a transmission in the HF band, the selection in the payload subband S of a set of n frequency channels of identical width according to a frequency allocation plan and the quality of the link of each of said channels, or the simultaneous transmission on the n frequency channels of a signal complying with an HF waveform.

Claims

1. A method for adaptive communications in an HF frequency band, comprising the steps of:

determination of a payload subband S that is available for a transmission in the HF band, depending on at least one of the following two criteria

a number of frequencies allocated to the user included in the payload subband S according to said frequency allocation plan,

a physical availability of the payload subband S evaluated as a function of a prediction of the interference induced on the signal by the reflections on the ionospheric layers;

selection in the payload subband S of a set of n frequency channels of identical width according to a frequency allocation plan and the quality of the link of each of said channels; and

simultaneous transmission on the n frequency channels of a signal complying with an HF waveform.

2. The method as claimed in claim 1, wherein the quality of the link of each of said channels is estimated at least on the basis of the following substeps:

measurement of the power of the received signal, in the absence of communication, in each frequency channel contained in the payload subband S,

attribution of a quality score to each of said frequency channels as a function of the comparison of said power with one or more predetermined thresholds, said quality decreasing with the increase in power,

selection of the n channels having the highest quality scores.

3. The method as claimed in claim 1, wherein the selection of said set of n frequency channels is updated periodically or when the quality score of a selected channel is degraded.

4. The method as claimed in claim 2, further comprising the following test step:

determining the number of frequency channels for which the quality of the link is greater than a minimum threshold required for a transmission to be possible on these channels,

if said number is less than the number n of channels required for the transmission, determining another available payload subband S.

5. The method as claimed in claim 2, wherein the quality of the link of each of said channels is estimated also with the aid of a measurement of the average power of the received signal over a period of elapsed time.

6. The method as claimed in claim 1, wherein the width of a frequency channel is equal to 3 kHz.

7. An HF band communication system comprising at least one HF transmitter and one HF receiver adapted to transmit and receive an HF waveform signal, wherein:

said HF receiver comprises means for determining a payload subband S that is available for a transmission in the HF band, and for selecting, in the payload subband S, a set of n frequency channels of identical width according to a frequency allocation plan and the quality of the link of each of said channels and transmitting to said HF transmitter said set of n selected frequency channels,

said HF transmitter comprises means for receiving a set of n selected frequency channels and simultaneously transmitting over the n frequency channels a signal complying with said HF waveform, and

said communication system also comprising means for using the adaptive communication method as claimed in any one of claims 1 to 6.