Demonstration of an OLA-based Cooperative Routing Protocol in an Indoor Environment

Concurrent cooperative transmission (CCT) is a cooperative transmission (CT) technique, also known as distributed transmit diversity, where a collection of single-antenna nodes induce a signal-to-noise-ratio advantage in a receiver by transmitting multiple copies of the same message, at the same time, in multiple diversity channels. CCT has been considered in many physical layer system studies including realistic demonstrations, which presented cooperative diversity gain in terms of error rate improvement or range extension. However, there have been very few attempts to evaluate CCT-based network routing schemes on a testbed with consideration of the overheads and challenges that CCT poses to the higher layers. In this paper, we compare the OLAROAD cooperative routing protocol with the conventional Ad hoc On Demand Distance Vector (AODV) protocol, on an ad hoc network of software defined radios. OLAROAD is based on a physical layer that forms opportunistic large arrays (OLAs). We evaluate the performance of the protocols on a linear network topology in a typical office building in terms of hop count, round trip time, packet delivery ratio and route discovery time, so that the advantages and disadvantages of CCT-based routing algorithm may be observed.