Patent ID: 7024188

Claim:
A method for use in a wireless LAN-system of the 802.11-type for avoiding interference between radar signals and the signals exchanged between a plurality of wireless broadcasting nodes in the system, the method comprising the steps of: enabling one of the nodes in the system to function as a radar controlling node (RCN) and letting said RCN carry out measurement on at least one frequency in a frequency band which has been assigned to the system, said measurements being carried out to detect if said at least one frequency is being utilized by a device or a system foreign to said wireless communications system, such as a radar device or system, the measurement being enabled to be carried out by means of the RCN transmitting a “quiet” message to other nodes in the system, said “quiet” message being a message which prohibits other nodes from transmitting during a certain interval defined in the “quiet” message, which method is characterized in that: said “quiet” message is contained in the beacon message of the 802.11-system, as an Information Element (IE) in the Beacon message, the “quiet” message which is transmitted contains information about the start of said interval, as well as the duration of the interval, the “quiet” message is transmitted redundantly in each Beacon message by the RCN.