| 摘要 |
<p>The present invention is related to a method for selecting a frequency channel of given bandwidth in a cognitive radio application comprising :
- considering a frequency bin from a plurality of frequency bins,
- evaluating at the considered frequency bin a function indicative of the frequency occupancy,
- if the evaluation result indicates free spectrum at the considered frequency bin, repeating the previous step for a frequency bin adjacent to the considered frequency bin until the free frequency bins constitute a frequency channel of the given bandwidth,
- if the evaluation result indicates occupied spectrum at the considered frequency bin, performing the step of evaluating for a next frequency bin determined by carrying out the substeps of :
—‹ calculating a measure of the left and right derivative, respectively, of the function at the considered frequency bin,
—‹ taking the measure of the left or right derivative as gradient approximation depending on which of the two provides the steepest descent,
—‹ determining the next frequency bin by shifting the considered frequency bin over a frequency shift inversely proportional to the gradient approximation.</p> |
