SDR-based Demonstration System and Applicability of SNR Aggregation for Multistage Distributed Cooperative Communication in MANETs

Multistage or hierarchical distributed cooperative communication on the physical layer is a promising approach to overcome the scalability limitation of Mobile Ad-hoc Networks (MANETs). Standalone nodes that could successfully decode messages join transmission and support each other. They become a virtual transmit cluster and send simultaneously. While information theoretic research has demonstrated that an approximately linear scaling behaviour can be achieved, imperfections and constraints of practical systems have not been taken into account. Within this paper, we present a scalable and modular low-cost demonstration system based on software-defined radios (SDRs) to study distributed cooperative communication in practical MANETs. Furthermore, we apply SNR aggregation in combination with distributed cooperative transmission. To this end, we show a practical implementation approach and investigate the performance by measurements and simulations. Our results clearly highlight the advantages of combining distributed cooperative communication and SNR aggregation, e. g. to overcome larger distances in a distributed long haul multiple-input single-output (MISO) scenario or to enable a more efficient broadcast.