Cooperative Forwarding Using Distributed MISO in OFDMA Multihop Networks

Abstract

In this work, we investigate cooperative multihop communications based on OFDMA and fountain codes. Data packets are forwarded between clusters of simultaneously transmitting nodes which exploit the diversity of links by sharing the available subcarriers based on local channel conditions. Furthermore, to enable distributed MISO transmissions between clusters, we investigate the potential of distributing data packets within the cluster by single node transmissions prior to the common transmissions aiming to increase the achievable throughput. We present two novel forwarding schemes that utilize distributed MISO transmissions while taking advantage of the properties of fountain codes. The first scheme relies on a full distribution of all data packets within each cluster while the second scheme adapts the extent to which data packets are distributed within the cluster according to local channel conditions. The proposed schemes are compared to an exclusive SISO forwarding scheme in which no additional distribution within each cluster is used.