A method comprising: transmitting, from a wireless access point device configured to operate in a wireless network, a request-to-send packet and/or a multi-user request-to-send packet that is addressed at least to a designated one (30) of a plurality of wireless client devices (30,..., 30), as part of a multi-user reservation sequence prior to a multi-user transmission from the wireless access point device to the plurality of wireless client devices (30,..., 30) that are the intended recipients for the multi-user transmission, wherein the designated wireless client device (30) has been assigned primary access holder for the multi-user transmission and is characterised by, the request-to-send packet and/or the multi-user request-to-send packet comprising: duration information, address information configured to address at least some of the plurality of wireless client devices (30,..., 30), and information indicating that the designated one (30) of the plurality of wireless client devices (30,..., 30) is to first transmit a clear-to-send packet (66, 80) after the request-to-send packet and/or the multi-user request-to-send packet, and provoking the designated wireless client device (30) to first transmit the clear-to-send packet (66, 80) in response to the request-to-send packet and/or the multi-user request-to-send packet; determining whether a clear-to-send packet (66, 80) is received from the designated wireless client device (30); and receiving clear-to-send packets (80,..., 80) transmitted from the remaining two or more of the plurality of wireless client devices (30,..., 30) in response to the multi-user request-to-send packet, each clear-to-send packet comprising identical content. transmitting, from a wireless access point device configured to operate in a wireless network, a request-to-send packet and/or a multi-user request-to-send packet that is addressed at least to a designated one (30) of a plurality of wireless client devices (30,..., 30), as part of a multi-user reservation sequence prior to a multi-user transmission from the wireless access point device to the plurality of wireless client devices (30,..., 30) that are the intended recipients for the multi-user transmission, wherein the designated wireless client device (30) has been assigned primary access holder for the multi-user transmission and is characterised by, the request-to-send packet and/or the multi-user request-to-send packet comprising: duration information, address information configured to address at least some of the plurality of wireless client devices (30,..., 30), and information indicating that the designated one (30) of the plurality of wireless client devices (30,..., 30) is to first transmit a clear-to-send packet (66, 80) after the request-to-send packet and/or the multi-user request-to-send packet, and provoking the designated wireless client device (30) to first transmit the clear-to-send packet (66, 80) in response to the request-to-send packet and/or the multi-user request-to-send packet; duration information, address information configured to address at least some of the plurality of wireless client devices (30,..., 30), and information indicating that the designated one (30) of the plurality of wireless client devices (30,..., 30) is to first transmit a clear-to-send packet (66, 80) after the request-to-send packet and/or the multi-user request-to-send packet, and provoking the designated wireless client device (30) to first transmit the clear-to-send packet (66, 80) in response to the request-to-send packet and/or the multi-user request-to-send packet; determining whether a clear-to-send packet (66, 80) is received from the designated wireless client device (30); and receiving clear-to-send packets (80,..., 80) transmitted from the remaining two or more of the plurality of wireless client devices (30,..., 30) in response to the multi-user request-to-send packet, each clear-to-send packet comprising identical content.