Patent ID: 7949345

Claim:
A Cognitive Radio (CR) system for distinguishing channels without interference from other RF devices in Wireless Local Area Network (WLAN) comprises: (a) a WLAN-event sensor for detection WLAN event happening in current channel signal; (b) a Receiving-Signal-Strength-Indicator-event sensor (RSSI-event sensor) for detecting RSSI-event happening in current channel signal; (c) an average computer for computing an average value of RSSI (RSSI_AVG) in current channel during RSSI-event happening; (d) a WLAN packet counter for counting a number of WLAN packets (WLAN_CNT) in current channel during WLAN-event happening; (e) a first available-channel for selecting one and plurality of channels with small RSSI_AVG and WLAN_CNT=0 to an available channel list and sorting the one and plurality of rest channels out of the available channel list from low RSSI_AVG to high RSSI_AVG to a sorting list; (f) a second available-channel selector for selecting one and plurality of channels without any WLAN event from sequence of the sorting list to the available channel list and deleting the one and plurality of selected channels from the sorting list; and (g) a third available-channel selector for sorting one and plurality of channels in the sorting list by their WLAN_CNT and storing them to the available channel list from small to large WLAN_CNT, wherein the WLAN channels include channels in 2.4 GHz Industrial, Scientific and Medical band (ISM band) and Unlicensed National Information Infrastructure band (UNII band).