Patent ID: 8462709

Claim:
An apparatus comprising: a receiver configured to receive a signal on a shared channel comprising at least a primary channel and a secondary channel; an energy calculator configured to calculate an energy measurement of a plurality of tones of the primary channel and an energy measurement of a plurality of tones of the secondary channel and to compute an energy difference between the energy measurement of the primary channel and the energy measurement of the secondary channel, wherein calculating the energy measurement of the plurality of tones of the primary channel comprises aggregating the energy of the plurality of tones of the primary channel and wherein calculating the energy measurement of the plurality of tones of the secondary channel comprises aggregating the energy of the plurality of tones of the secondary channel; and a processor configured to detect interference in response to the energy measurement of the primary channel and the energy measurement of the secondary channel, wherein detecting interference comprises determining interference in a second mode, in which transmission is expected on the primary channel and the secondary channel, when the computed energy difference is above an energy difference threshold.