A method of requesting a plurality of different characteristic indicators from a second communication apparatus (MS) in a wireless communication network comprising a first communication apparatus (BS) and a plurality of such second communication apparatuses (MS) which communicate with the first communication apparatus using a shared communication frame, the method comprising; the first communication apparatus (BS) transmitting (110) a single standing instruction to the second communication apparatus (MS) to interchange between sending the different characteristic indicators in a feedback window allocated to the second communication apparatus in the shared communication frame.