A resource requirement aware transmit strategy for non-regenerative multi-way relaying

Non-regenerative multi-antenna multi-way relaying is considered. The scenario consists of a group of single-antenna nodes that want to communicate using multiple subcarriers. Each node has a message which every other node in the group should receive. The communications between the nodes are performed via a half-duplex multi-antenna relay station. It is assumed that the nodes have individual resource requirements. A new transmit strategy, in which the individual resources requirements of the nodes are considered, is proposed. To ensure that the relay station has enough spatial dimensions to separate the incoming signals, it is proposed that the number of transmitting nodes per subcarrier is equal to the number of antennas at the relay station. Moreover, it is proposed that the required numbers of subcarriers are calculated according to the buffer level of the nodes, reflecting the amount of data a node has to transmit. To allocate the required number of subcarriers to each node, the proposed transmit strategy performs an efficient subcarrier allocation. Numerical results show that the proposed strategy outperforms existing transmit strategies especially when the number of antennas at the relay station is smaller than the number of nodes.