COLiDeR: A cross-layer protocol for two-path relaying

摘要

In this work, we present COLiDeR, the first PHY/MAC cross-layer protocol for practical two-path relaying using off-the-shelf half-duplex radios. It relies on three main contributions. First, based on an off-line performance comparison, COLiDeR selects the best interference management technique for a radio to handle two overlapping signals depending on the measured channel conditions. Then, considering the real decoding capacities of the nodes, COLiDeR introduces a dynamic relaying strategy with the objective of achieving high throughput while reducing decoding failures. This includes a light-weight protocol for the source to evaluate the channel state, a state-machine modeled approach driven by the source for switching between the defined scheduling schemes and an optional power adaptation mechanism for reducing the packet losses. Finally, COLiDeR comes with an adapted scheduling mechanism that aims to integrate two path-relaying in multi-hop wireless networks. Experiments on a 4-USRP testbed show that COLiDeR delivers between 80%-95% of the relaying performance of an ideal full-duplex radio while incurring negligible decoding failures. Just as important, large-scale simulations show that COLiDeR improves network throughput in multihop topologies by over 20% compared to traditional interference-free transmissions.