A method and system for defining a transmission of data within a transmission opportunity (TXOP) is described. Aspects of the present system and method are related to wireless local area network (WLAN) systems. In one embodiment, aspects of the present system may be utilized within a WLAN system operating in accordance with frame aggregation mechanisms. Other aspects of the system specify the role of access point (AP) and non-AP stations operating in a bidirectional single receiver aggregation procedure. Aspects of the described system and method provide control to an AP or other station to limit the duration of the response burst, including acknowledgement message, aggregated with one or more data frames. Other aspects indicate how bidirectional single receiver aggregate data flow should be used in infrastructure, mesh and ad hoc operation scenarios.