CIF:Small: Collaborative Research:Theoretical Foundation of Distributed Wireless Channel Access

由于缺乏对如何在空间分布的用户之间共享无线媒体的基本理解，无线网络的能耗和带宽效率仍然不足，并且高度次优。先前对无线频道接入的调查遵循了两条不同的路径，反映了截然不同的观点；即，传统的信息论方法假设了完美的用户协调，忽略了模块化的网络体系结构，而传统的网络理论方法主要关注访问控制协议，忽略了物理层的影响。本课题将通过建立分布式无线系统信道接入的理论基础，弥合经典理论的差距。更具体地说，它将通过开发用于物理层分布式通信的信道编码理论来扩展经典信息理论，其中用户不共同设计信道编码。它还将通过开发用于分布式网络的介质访问控制（MAC）框架来扩展经典网络理论，其中物理层属性，如联合多用户消息解码和通信参数的灵活适应，在链路层得到有效利用。该项目包括两个部分，分别解决了分布式无线网络的物理层和数据链路层。在项目的第一部分中，目标是开发一个严格的编码理论来描述分布式通信系统的基本限制。编码理论将支持广泛的通信性能权衡和低计算复杂度的结构化编码方案。项目的第二部分包含三个步骤。第一步的目标是表征最优链路层分布式信道共享方案，它们的基本特性和性能优于经典方案。第二步的目标是开发统一的MAC框架，通过联合自适应通信参数（如速率、功率、传输概率）实现分布式网络中渐近最优信道共享。第三步的目标是开发具有快速收敛特性的MAC算法，以确保网络在瞬态环境下的高效运行。通过将信息理论扩展到分布式通信模型，推进信息与网络理论的融合，显著提高无线系统的能量和带宽效率。两种经典理论的统一也将影响现代通信网络学科在高等教育中的教学方式，并吸引更多有才华的学生进入这一具有重大国家意义的领域。

Due to lack of fundamental understanding on how to share wireless media among spatially distributed users, the energy consumption and bandwidth efficiency of wireless networks remains defficient and highly suboptimal. Prior investigations of wireless channel access have followed two separate paths that reflect vastly different viewpoints; namely, the traditional information-theoretic approach assumes perfect user coordination and ignores the modularized network architecture, while the traditional network-theoretic approach largely focuses on access control protocols and ignores the impact of the physical layer. This project will bridge the gap of the classical theories by developing a theoretical foundation for channel access in distributed wireless systems. More specifically, it will extend classical information theory by developing a channel coding theory for physical layer distributed communication, where users do not jointly design channel codes. It will also extend classical network theory by developing a medium access control (MAC) framework for distributed networking, where physical layer properties, such as joint multiuser message decoding and flexible adaptation of communication parameters, are efficiently exploited at the link layer.The project contains two parts which respectively address the physical and the data link layers of distributed wireless networks. In Part I of the project, the goal is to develop a rigorous coding theory to characterize the fundamental limitis of distributed communication systems. The coding theory will support extensive communication performance tradeoffs and structured coding schemes with low computational complexity. Part II of the project contains three steps. The objective of the first step is to characterize optimal link layer distributed channel sharing schemes, their fundamental properties and performance improvements over classical schemes. The objective of the second step is to develop a unified MAC framework to achieve asymptotic optimal channel sharing in distributed networks via the joint adaptation of communication parameters (e.g., rate, power, transmission probability). The objective of the third step is to develop MAC algorithms with fast convergence properties that ensure efficient network operation in transient environments.By extending information theory to distributed communication models, the project will advance the integration of information and network theories, and significantly improve the energy and bandwidth efficiency of wireless systems. Unification of the two classical theories will also influence the way modern communication network subjects are taught in Higher Education and attract more talented students to this field of acute national importance.