Delay-Constrained Multihop Transmission in Wireless Networks: Interaction of Coding, Channel Access, and Routing

现代无线通信网络越来越多地采用多跳传输。这些网络是我国未来通信和监测基础设施的核心。多跳的基本动机是传输发生在较短的距离上——因此接收到的信号强度更高——通过许多中间节点，而不是在信息源和目的地之间的较长距离上——因此接收到的信号强度较低。然而，多跳传输涉及物理层信道编码、链路层分布式信道访问和网络层多跳路由之间复杂的相互作用。这些技术在很大程度上是由不同的社区单独研究的，而本项目侧重于它们的相互作用，特别是在延迟受限的情况下。本研究涉及一般无线多跳网络的模型，并开发沿多达M + 1节点的单个路由传输的权衡。终端节点之间的传输可以发生在单跳中，也可以发生在M跳中。多跳传输提高了中间节点接收信噪比；然而，这种观察并没有考虑功率和带宽分配、端到端延迟、错误传播或其他发射机引起的干扰等重要的实际问题。在其他结果中，初步研究表明，多跳的好处被这些问题所侵蚀，特别是对于高频谱效率，即相对于可用带宽的高数据速率。研究人员从通信理论、数学网络和网络实践的角度对多跳传输进行了全面的研究，目的是提供影响我们社会主要部分的解决方案。

Multihop transmission is increasingly being incorporated into modern wireless communication networks. These networks are central to our nation's future communications and monitoring infrastructures. Thebasic motivation for multihop is that transmissions occur over shorter distances -- and therefore with higher received signal strength -- via many intermediate nodes rather than over longer distances -- andtherefore with lower received signal strength -- between the source and destination of the information. However, multihop transmission involves complex interactions among channel coding at the physicallayer, distributed channel access at the link layer, and multihop routing at the network layer. These techniques have been studied largely in isolation by different communities, whereas this projectfocuses on their interaction, especially in delay-constrained scenarios.This research involves models for general wireless multihop networks, and develops tradeoffs for transmission along an individual routes of up to M + 1 nodes. Transmission between the end nodes can occur in a single hop, or up to M hops. Multihop transmission increases the received signal-to-noise ratio (SNR) at intermediate nodes; however, this observation does not take into account the important practical issues of power and bandwidth allocation, end-to-end delay, error propagation, or interference induced by other transmitters. Among other results, preliminary research indicates that the benefits of multihop are eroded by these issues, especially for high spectral efficiency, i.e., high data rates relative to the available bandwidth. The investigators take a comprehensive look at multihop transmission from the point of view of communication theory, mathematical networking, and networking practice, with the goal of offering solutions that will impact a major part of our society.