Apparatuses, methods, and computer program products for communication are provided. In an aspect, an apparatus for communication may include a processing system configured to receive a frame configured to assign at least member information or position information for one or more identifiers, and receive a data packet associated with a particular identifier and indicating a number of space-time streams for one or more position information. In another aspect, an apparatus for communication may include a processing system configured to transmit a frame configured to assign at least member information or position information for one or more identifiers, and transmit a data packet associated with a particular identifier and indicating a number of space-time streams for one or more position information.