Patent ID: 8326227

Claim:
A method for transmitting information, the method comprising: (1) setting a directional antenna of a transmitter of a cognitive radio system to a first transmission direction; (2) determining whether a state of a spectrum band in the first transmission direction is idle or busy; (3) transmitting the information in the first transmission direction to a receiver of the cognitive radio system when the spectrum band state is idle and the receiver lies within a coverage area of the transmitter; (4) transmitting the information in the first transmission direction to a first relay when the spectrum band state is idle and the receiver lies without the coverage area of the transmitter; and when the spectrum band state is busy: (5) determining whether a group of untested transmission directions of the directional antenna is empty or not empty, (6) selecting an untested transmission direction from the group of untested transmission directions when the group of untested transmission directions is not empty, (7) determining whether the state of the spectrum band in the untested transmission direction is idle or busy, (8) transmitting the information in the untested transmission direction to the receiver when the spectrum band state is idle and the receiver lies within a coverage area of the transmitter, and (9) transmitting the information in the untested transmission direction to a second relay when the spectrum band state is idle and the receiver lies without the coverage area of the transmitter; and (10) when the group of untested transmission directions is empty, (11) buffering the information.