A mobile device, comprising: a radio configured to perform wireless communication within a wireless network; at least one processor coupled to the radio, wherein the at least one processor is configured to cause the mobile device to: detect, via the radio, a first transmission occupying a first frequency band within an operating bandwidth of the wireless network, wherein the first transmission is transmitted by a remote wireless device; in response to determining that the first transmission does not occupy a second, different frequency band within the operating bandwidth of the wireless network, transmit, via the radio, a second transmission occupying the second frequency band concurrent with the first transmission; determine whether the remote wireless device is configured to assess the state of all frequency bands within the operating bandwidth before beginning a subsequent transmission based on evaluating the first transmission; characterised in that the at least one processor is configured to cause the mobile device to: in response to determining that the remote wireless device is not configured to assess the state of all frequency bands within the operating bandwidth before beginning a subsequent transmission, set a duration of the second transmission such that the second transmission will terminate not later than an expected end time of the first transmission; and in response to determining that the remote wireless device is configured to assess the state of all frequency bands within the operating bandwidth before beginning a subsequent transmission, set the duration of the second transmission without regard to the expected end time of the first transmission. a radio configured to perform wireless communication within a wireless network; at least one processor coupled to the radio, wherein the at least one processor is configured to cause the mobile device to: detect, via the radio, a first transmission occupying a first frequency band within an operating bandwidth of the wireless network, wherein the first transmission is transmitted by a remote wireless device; in response to determining that the first transmission does not occupy a second, different frequency band within the operating bandwidth of the wireless network, transmit, via the radio, a second transmission occupying the second frequency band concurrent with the first transmission; determine whether the remote wireless device is configured to assess the state of all frequency bands within the operating bandwidth before beginning a subsequent transmission based on evaluating the first transmission; characterised in that the at least one processor is configured to cause the mobile device to: in response to determining that the remote wireless device is not configured to assess the state of all frequency bands within the operating bandwidth before beginning a subsequent transmission, set a duration of the second transmission such that the second transmission will terminate not later than an expected end time of the first transmission; and in response to determining that the remote wireless device is configured to assess the state of all frequency bands within the operating bandwidth before beginning a subsequent transmission, set the duration of the second transmission without regard to the expected end time of the first transmission. detect, via the radio, a first transmission occupying a first frequency band within an operating bandwidth of the wireless network, wherein the first transmission is transmitted by a remote wireless device; in response to determining that the first transmission does not occupy a second, different frequency band within the operating bandwidth of the wireless network, transmit, via the radio, a second transmission occupying the second frequency band concurrent with the first transmission; determine whether the remote wireless device is configured to assess the state of all frequency bands within the operating bandwidth before beginning a subsequent transmission based on evaluating the first transmission; in response to determining that the remote wireless device is not configured to assess the state of all frequency bands within the operating bandwidth before beginning a subsequent transmission, set a duration of the second transmission such that the second transmission will terminate not later than an expected end time of the first transmission; and in response to determining that the remote wireless device is configured to assess the state of all frequency bands within the operating bandwidth before beginning a subsequent transmission, set the duration of the second transmission without regard to the expected end time of the first transmission.