Patent ID: 7715343

Claim:
A radio terminal which carries out data transmission using a plurality of frequency bands including frequency bands licensed to other licensed radio terminals, comprising: a detection section configured to detect a radio signal for each frequency band; a judging section configured to carry out a modulation analysis by sampling the detected radio signal and calculating frequency and time statistical values of the detected radio signal; to judge, based on a pattern recognition method, whether or not the calculated statistical values match statistical features of a modulation scheme of a licensed radio terminal; and thereby to judge whether the detected radio signal is a radio signal from a licensed radio terminal or not; a selection section configured to select frequency bands in which periods that no radio signal from licensed radio terminals are detected are equal to or exceed a first threshold and in which frequency band utilization rates by unlicensed radio terminals are equal to or lower than a second threshold, as a plurality of frequency bands to be used for data transmission based on the judgment result; a schedule generation section configured to generate a schedule for intermittent data transmissions using the plurality of selected frequency bands by determining a continuous data transmission time in each intermittent data transmission such that the utilization rate falls to or below the second threshold for each of the selected frequency bands; a data generation section configured to generate data for the intermittent data transmissions; a data transmission section configured to transmit the generated data according to the schedule; a carrier sensing section configured to carry out carrier sensing on a frequency band in which data is transmitted before data transmission for each of the intermittent data transmissions; and a control section configured to stop, when the carrier sensing result shows that a radio signal from a licensed radio terminal is detected in a certain frequency band, data transmission using at least the certain frequency band.