This document discloses a solution for detecting a transmission opportunity. According to an aspect, a method comprises as performed by an apparatus of a first wireless network: detecting a first transmission from a first apparatus of a second wireless network different from the first wireless network; transmitting, to a second apparatus of the first wireless network, a transmission mode request, wherein the transmission mode request indicates a request to transmit from the apparatus to the second apparatus at least during an interframe space of a transmission opportunity between the first apparatus and another apparatus of the second wireless network, receiving a transmission mode response from the second apparatus, wherein the transmission mode response indicates acceptance of the request; in response to detecting a second transmission from the first apparatus, transmitting a data frame during an interframe space following the second transmission.