An apparatus for wireless communication comprising: means for receiving a frame indicating an announcement of a switch to a particular bandwidth; means for determining whether the particular bandwidth belongs to a first or second set of operating bandwidths; and means for switching to the first or second set of operating bandwidths, wherein the first set of operating bandwidths comprises 80 MHz, 80+80 MHz and 160 MHz operating bandwidths and wherein the second set of operating bandwidths comprises 20 MHz and 40 MHz operating bandwidths; wherein the means for determining comprises means for detecting a presence or absence of a Secondary Channel Offset Element and a Wide Bandwidth Channel Switch Element , wherein the presence of the Secondary Channel Offset Element and the Wide Bandwidth Channel Switch Element in the frame indicates that the particular bandwidth belongs to the first set of operating bandwidths, and characterised in that the absence of the Secondary Channel Offset Element and the Wide Bandwidth Channel Switch Element in the frame indicates that the particular bandwidth belongs to the second set of operating bandwidths wherein, if the particular bandwidth is indicated to be in the first set of operating bandwidths, and if the frame includes an Extended Channel Switch Announcement Element or an Extended Channel Switch Announcement Frame, a New Operating Class field of the frame comprises information that identifies a primary 40 MHz channel to be used by the apparatus after the switch, the New Operating Class field being different than the Secondary Channel Offset Element and the Wide Bandwidth Channel Switch Element. means for receiving a frame indicating an announcement of a switch to a particular bandwidth; means for determining whether the particular bandwidth belongs to a first or second set of operating bandwidths; and means for switching to the first or second set of operating bandwidths, wherein the first set of operating bandwidths comprises 80 MHz, 80+80 MHz and 160 MHz operating bandwidths and wherein the second set of operating bandwidths comprises 20 MHz and 40 MHz operating bandwidths; wherein the means for determining comprises means for detecting a presence or absence of a Secondary Channel Offset Element and a Wide Bandwidth Channel Switch Element , wherein the presence of the Secondary Channel Offset Element and the Wide Bandwidth Channel Switch Element in the frame indicates that the particular bandwidth belongs to the first set of operating bandwidths, and characterised in that the absence of the Secondary Channel Offset Element and the Wide Bandwidth Channel Switch Element in the frame indicates that the particular bandwidth belongs to the second set of operating bandwidths wherein, if the particular bandwidth is indicated to be in the first set of operating bandwidths, and if the frame includes an Extended Channel Switch Announcement Element or an Extended Channel Switch Announcement Frame, a New Operating Class field of the frame comprises information that identifies a primary 40 MHz channel to be used by the apparatus after the switch, the New Operating Class field being different than the Secondary Channel Offset Element and the Wide Bandwidth Channel Switch Element. <EOS>