A communication station comprising: a transceiver configured to communicate on a primary 20 MHz channel, and three or more secondary channels including a secondary 20 MHz channel, a secondary 40 MHz channel and a secondary 80 MHz channel for operating channel widths of 20 MHz, 40 MHz, 80 MHz and 160 MHz and characterized in that the transceiver circuitry is configured to perform channel assessment in accordance with an energy detection,ED, technique; and wherein the communication station further comprises: processing circuitry, wherein as part of the ED technique, the processing circuitry is to configure the transceiver to: issue a primary channel busy condition when a start of a 20 MHz data unit is detected in the primary 20 MHz channel at or above a first predetermined energy level; and issue a secondary channel busy condition when a primary channel busy condition has not been issued and when: any signal is detected within the secondary 20 MHz channel at or above a second predetermined energy level; or a 20 MHz data unit is detected in the secondary 20 MHz channel or a 20 MHz subchannel of either the secondary 40 MHz channel or the secondary 80 MHz channel at or above a third predetermined energy level; and wherein the transceiver is further configured to refrain from transmitting on any one of the secondary channels for which a secondary channel busy condition has been issued. a transceiver configured to communicate on a primary 20 MHz channel, and three or more secondary channels including a secondary 20 MHz channel, a secondary 40 MHz channel and a secondary 80 MHz channel for operating channel widths of 20 MHz, 40 MHz, 80 MHz and 160 MHz and characterized in that the transceiver circuitry is configured to perform channel assessment in accordance with an energy detection,ED, technique; and wherein the communication station further comprises: processing circuitry, wherein as part of the ED technique, the processing circuitry is to configure the transceiver to: issue a primary channel busy condition when a start of a 20 MHz data unit is detected in the primary 20 MHz channel at or above a first predetermined energy level; and issue a secondary channel busy condition when a primary channel busy condition has not been issued and when: any signal is detected within the secondary 20 MHz channel at or above a second predetermined energy level; or a 20 MHz data unit is detected in the secondary 20 MHz channel or a 20 MHz subchannel of either the secondary 40 MHz channel or the secondary 80 MHz channel at or above a third predetermined energy level; and wherein the transceiver is further configured to refrain from transmitting on any one of the secondary channels for which a secondary channel busy condition has been issued. processing circuitry, wherein as part of the ED technique, the processing circuitry is to configure the transceiver to: issue a primary channel busy condition when a start of a 20 MHz data unit is detected in the primary 20 MHz channel at or above a first predetermined energy level; and issue a secondary channel busy condition when a primary channel busy condition has not been issued and when: any signal is detected within the secondary 20 MHz channel at or above a second predetermined energy level; or a 20 MHz data unit is detected in the secondary 20 MHz channel or a 20 MHz subchannel of either the secondary 40 MHz channel or the secondary 80 MHz channel at or above a third predetermined energy level; and wherein the transceiver is further configured to refrain from transmitting on any one of the secondary channels for which a secondary channel busy condition has been issued. issue a primary channel busy condition when a start of a 20 MHz data unit is detected in the primary 20 MHz channel at or above a first predetermined energy level; and issue a secondary channel busy condition when a primary channel busy condition has not been issued and when: any signal is detected within the secondary 20 MHz channel at or above a second predetermined energy level; or a 20 MHz data unit is detected in the secondary 20 MHz channel or a 20 MHz subchannel of either the secondary 40 MHz channel or the secondary 80 MHz channel at or above a third predetermined energy level; and wherein the transceiver is further configured to refrain from transmitting on any one of the secondary channels for which a secondary channel busy condition has been issued. any signal is detected within the secondary 20 MHz channel at or above a second predetermined energy level; or a 20 MHz data unit is detected in the secondary 20 MHz channel or a 20 MHz subchannel of either the secondary 40 MHz channel or the secondary 80 MHz channel at or above a third predetermined energy level; and wherein the transceiver is further configured to refrain from transmitting on any one of the secondary channels for which a secondary channel busy condition has been issued.