Patent ID: 8451808

Claim:
A method comprising: transmitting a channel switch announcement frame to announce a channel switch for a 40 MHz channel of a wireless communications network, the channel including a 20 MHz primary channel and a 20 MHz secondary channel, the channel switch announcement frame including a channel switch announcement element and channel offset element; wherein the channel switch announcement element contains a channel number field, the channel number field indicating a number of the channel being switched to; wherein the channel offset element includes an element ID field, a length field and channel offset field, the channel offset field indicating a first value or a second value when a 20 MHz secondary channel is included in the channel of wireless communications network, the first and second values each indicating a position of the 20 MHz secondary channel relative to the 20 MHz primary channel; and wherein the channel offset field indicates a third value when no 20 MHz secondary channel is included in the 40 MHz channel of the wireless communications network.