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

无线自组织网络完全由廉价的移动节点组成，这些节点在没有昂贵的固定基础设施(如基站)的情况下运行。为了节省能量、提高数据传输速率或提高健壮性，一些节点可以充当帮助节点，转发部分或全部信息。在最简单的中继形式中，数据分组以类似于消防队的方式逐个节点转发。在更高级的方法中，如本研究中考虑的方法，多个节点可以协作转发信息。关键的设计问题有两个方面。首先是协作通信技术的设计，即将信息从一组节点转发到下一组节点的物理层方法。第二是路由，即标识哪些可用节点应该参与传输以及应该为每个节点分配什么系统资源(时间、能量、带宽)。这项研究分析了这两个关键问题之间的相互联系，这两个问题在大多数先前的工作中是分开处理的。我们考虑在物理层使用无码率编码时的路由问题。这样的编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)。这将产生更高的网络健壮性和效率。这项研究调查了当多条消息同时传输时自动产生的干扰的影响。通过使用随机网络优化，可以提供最优资源分配，而不需要集中了解节点和传播信道的所有状态。研究了基于网络编码和计算转发相结合的协作传输技术及其无码率变体及其在协作路由中的应用。通过实验对概念进行了验证。

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.