CIF: Medium: Collaborative Research: Cooperative Routing in Wireless Ad-Hoc Networks with Advanced PHY Layers: Interference Management, Resource Allocation, and Information Mixing

无线ad-hoc网络仅由廉价的、移动的节点组成，这些节点在没有诸如基站之类的昂贵的固定基础设施的情况下运行。为了节省能量、增加数据速率或提高鲁棒性，一些节点可以充当帮助节点，中继信息中的一些或全部。 在最简单的中继形式中，数据包以类似于消防队的方式逐节点转发。在更先进的方法中，例如本研究中考虑的方法，多个节点可以合作转发信息。关键的设计问题有两个方面。 首先是协作通信技术的设计，即，用于将信息从一组节点中继到下一组节点的物理层方法。 第二个是路由，即，识别哪些可用节点应该参与传输以及应该向每个节点分配什么系统资源（时间、能量、带宽）。本研究分析了这两个关键问题之间的相互联系，在大多数以前的工作中分别对待。 我们考虑的路由问题时，无比率码采用在物理层。 这样的代码允许接收节点累积来自多个发送节点的互信息（而不仅仅是能量）。 这会产生更大的网络鲁棒性和效率。该研究调查了干扰的影响，当多个消息同时传输时，干扰会自动出现。 通过使用随机网络优化，可以提供最优的资源分配，而不需要集中的知识的所有状态的节点和传播信道。基于网络编码和计算转发的混合的协作传输技术，它们的无速率变体，以及应用于协作路由。通过实验验证了这些概念。

Wireless ad-hoc networks consist solely of cheap, mobile nodes that operate in the absence of expensive fixed infrastructure such as base stations. In order to save energy, increase data rate, or improve robustness, some nodes may act as helper nodes, relaying some or all of the information. In the simplest form of relaying, data packets are forwarded node-by-node in a manner akin to a fire bucket brigade. In more advanced methods, such as those considered in this research, several nodes can cooperate to forward information. The key design questions are two-fold. First is the design of cooperative communication techniques, i.e., physical-layer approaches for relaying information from one set of nodes to the next. Second is routing, i.e., identifying which of the available nodes should participate in the transmission and what system resources (time, energy, bandwidth) should be allocated to each. This research analyzes interconnections between these two key questions, treated separately in most prior work. We consider the routing problem when rateless codes are employed at the physical layer. Such codes allow receiving nodes to accumulate mutual information (instead of just energy) from multiple transmitting nodes. This yields greater network robustness and efficiency. The research investigates the effect of interference, which automatically arises when multiple messages are being transmitted simultaneously. By using stochastic network optimization, optimum resource allocation can be provided without the need for centralized knowledge of all states of nodes and propagation channels. Cooperative transmission techniques based on a hybrid of network-coding and compute-and-forward, their rateless variants, and application to cooperative routing are investigated as well. The concepts are validated through experiments.