Applicability of Space-Time Block Codes for Distributed Cooperative Broadcasting in MANETs with High Node Mobility

Mobile Ad-Hoc Networks (MANETs) are often characterized by high node mobility and rapid topology changes which in turn can cause high packet loss rates. In order to cope with this, MANETs typically rely on routing algorithms that try to efficiently distribute messages in the entire network. Such routing schemes introduce an overhead that limits the scalability of MANETs with respect to the number of nodes and/or mobility. Cooperative communication techniques have the potential to improve the efficiency of distributing messages and thus to increase the MANET scalability. In this paper, we propose an efficient cooperative broadcasting scheme based on distributed transmit diversity. To this end, we adapt Space-Time Block-Codes (STBCs), that were initially designed for a co-located setup in quasi-static environments, to a distributed setup with time-variant channels. We perform a comprehensive analysis based on bit error simulations to compare different STBC candidates and identify Linear-Scalable Dispersion Codes (LSDCs) to be a valuable option. For those, we propose an improvement of the inner-code for different channel models without the need for channel state information at the transmitter (CSIT). Besides, we validate the performance advantage of cooperative broadcasting by outage simulations in typical MANET scenarios.