NetSE: Small: Delay Minimization in Wireless Networks

传统信息论是从物理层的角度来研究传输问题的。信息论的目的是确定在给定的物理通信信道中发射机和接收机之间可实现的最大通信速率。在简化的源-信道-目的地模型中，信息论方法假设在传输开始之前发射机中有无限数量的比特可用性。蜂拥而至和相关的延误问题大多被忽视了。相比之下，网络理论对网络层问题进行了复杂的分析，如随机到达和网络延迟。然而，在网络理论方法中，底层物理层模型通常非常简化，例如，在大多数方法中不允许同时传输，即使允许同时传输，也使用碰撞通道模型，这太简单了，无法从信息论的角度捕捉物理层中可以实现的内容。本计划旨在对网路中的延迟问题有一个基本的了解，并设计传输方法和调度算法，以减少网路通信中的延迟。为此，本课题结合了信息论、网络理论、排队理论和优化理论等技术。研究人员使用信息论技术来提高潜在的信息携带率，并结合排队和网络理论工具，考虑外部到达率和当前队列大小，将这些率分配给网络用户。此外，研究人员将物理层现象，如衰落（使机会传输成为可能）和无意中听到的信息（使合作成为可能）纳入这一发展。此外，在节点能够从自然中获取能量的网络应用中，研究人员在设计传输和调度机制时考虑了随机数据包到达和随机能量到达（通过收集）到节点之间的相互作用。

Traditional information theory investigates transmission problems from a physical layer perspective. Information theory aims to determine largest achievable communication rates between transmitters and receivers for a given physical communication channel. In the simplified source-channel-destination model, information-theoretic approaches assume the availability of an infinite number of bits at the transmitters before the transmission starts. The burstiness of the arrivals and the associated issue of delay are mostly ignored. In contrast, network theory gives sophisticated analysis of network layer issues, such as random arrivals and network delay. However, in network-theoretic approaches, the underlying physical layer model is usually very simplified, e.g., in most approaches simultaneous transmissions are not allowed, and even when they are allowed, a collision channel model is used, which is far too simplistic to capture what can be achieved in the physical layer from an information-theoretic perspective.This project aims to develop a fundamental understanding for the issue of delay in networks, and design transmission methods and scheduling algorithms to minimize delay in network communications. Towards this goal, this project combines techniques from information theory, network theory, queueing theory and optimization theory. The investigators use information-theoretic techniques to improve the underlying information carrying rates, together with queueing- and network-theoretic tools to allocate these rates to network users considering external arrival rates and current queue sizes. Further, the investigators incorporate physical layer phenomena such as fading (enabling opportunistic transmissions) and overheard information (enabling cooperation) into this development. In addition, in networking applications where nodes are able to harvest energy from nature, the investigators consider the interactions between the random packet arrivals and the random energy arrivals (through harvesting) to nodes, in designing the transmission and scheduling mechanisms.