Adaptive resource allocation within three-stage OFDM relay networks

In this work we consider OFDM transmission, due to its potential for meeting the stringent quality of service (QoS) targets of next-generation broadband distributed wireless networks, over three-stage relay networks. In particular, we examine distributed adaptive space-frequency coding for generally asynchronous links composed of four transmit and/or receive antennas, i.e. exploiting quasi-orthogonal and extended-orthogonal coding schemes. The successful deployment of these closed-loop methods is dependent upon channel state information (CSI) being available for each stage of the network. Taking the maximum end-to-end data rate as the optimal criterion, an adaptive resource allocation (RA) scheme suitable for a wide range of signal-to-noise-ratios (SNRs) and a prescribed transmit power budget is proposed to distribute appropriate resources to each stage based on the channel state information (CSI) and knowledge of the network topology.