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.

在这项工作中，我们提出了COLiDeR，这是第一个用于使用现成的半双工无线电进行实际两路径中继的PHY / MAC跨层协议。它依靠三个主要贡献。首先，基于离线性能比较，COLiDeR为无线电选择最佳的干扰管理技术，以根据测得的信道条件处理两个重叠信号。然后，考虑节点的实际解码能力，COLiDeR引入了动态中继策略，目的是在减少解码失败的同时实现高吞吐量。这包括供源评估信道状态的轻量协议，由源驱动的状态机建模方法（用于在定义的调度方案之间进行切换）以及用于减少数据包丢失的可选功率自适应机制。最后，COLiDeR带有一种经过改进的调度机制，旨在将多跳无线网络中的两个路径中继集成在一起。在4-USRP测试台上进行的实验表明，COLiDeR可以提供理想的全双工无线电的中继性能的80％至95％，而解码失败却可以忽略不计。同样重要的是，大规模仿真表明，与传统的无干扰传输相比，COLiDeR将多跳拓扑中的网络吞吐量提高了20％以上。