We consider layered DF cooperation in a relayaided wireless multicast network. Spliting the source-message into two equal layers, we provide unequal power allocation to the individual layers through a simple mapping operation on a QAM constellation. The layering process thus allows the destinations to partially recover the message from the source's transmissions. At the relay, we propose a multiplexed-coded approach that, with a single transmission, caters for the disparity in the number of

more »

... rs decoded at different destinations. In addition to simulations, we validate the performance gains of the proposed strategy through a system-level implementation using software-defined radios. Catering for real-world factors such as carrier and timing synchronization, we conduct overthe-air experiments in an indoor office environment and find that the proposed scheme can achieve a frame-error-rate that is 25% of that with conventional two-hop DF relaying. Baseband Demodulator Message Preamble Superposition Demapper Conv Decoder Π -1 Conv Decoder Π -1 CRC Check CRC Check Multiplexed Coding & Transmission Fig. 3. Block diagram of the operations at the relay.