A method for minimizing processing and transmission power in a flexible and bidirectional OFDM wireless communication system including a MAC layer and a PHY layer, said PHY layer including a supervisor unit controlling in real time the performance of the PHY layer is disclosed. The method comprises feeding a first set of input data as to the QoS requirements at the PHY layer from the MAC layer to the supervisor unit comprising a Target Rate (required information rate), a Target BER (required Bit Error Rate) and a Max Delay (max tolerable delay); feeding a second set of input data including channel power transfer functions H=(|Hi|2(: (index i refers to the ith sub-carrier) from PHY layer to the supervisor unit; processing the first and second set of input data for minimizing processing and transmission power in a wireless communication network system; and outputting N, modulation and coding parameters and transmission power parameters to the PHY layer. The coding parameters and transmission power parameters to the PHY layer include C: Code rate data; B: Block length data; n: data as to the number of decoding iterations; M=(Mi(: data as to a set of codes to specify the generally different constellations adopted for the different sub-channels (e.g. Mi=0 means that the ith sub-channel is OFF, different values specify constellation types in the pre-defined available set); and P=(Pi(: data as to a set of the generally different transmission powers adopted for the different sub-channels (e.g. Pi=0 means that the ith sub-channel is OFF). The method is performed in a wireless communication system, in particular in a supervisor unit.