WiFiUS: Collaborative Research: Future Small-Cell Networks Using Reconfigurable Antennas

未来无线系统和服务的激增依赖于能够适应快速变化的无线环境的灵活的无线电体系结构的设计。由于可用频谱有限，调制和编码技术正接近其香农容量限制，通过增加频谱重用和干扰抑制来提高容量已成为未来蜂窝网络的优先事项。行业领先者一直专注于多层异类网络结构，其中部署了小小区(例如，微微小区、毫微微小区)基站以满足容量需求。在使小蜂窝基站全面部署成为可能的技术挑战中，干扰管理仍然是最大的挑战。该项目致力于为无线系统提供可用的硬件和算法工具，以便为小蜂窝基站的天线配置做出智能决策，以减轻干扰，提高网络容量和在异质网络环境中的共存。(二)算法与系统设计天线和收发信机设计；以及试验台实施。第一个重点是利用可重构天线的小蜂窝网络的数学建模和总体系统设计。整个系统设计的一个重要组成部分是为下行链路传输开发高效和有效的分析工具和算法，重点是定向网络设计、定向选择算法和基站用户关联。第二个推动力包括为小蜂窝基站开发实用的可重新配置天线和收发信机处理技术。项目团队正在采用可重新配置的超材料和Alford环形天线设计，以提供具有波束控制和可变波束宽度能力的紧凑型可重新配置天线架构。利用这些新的天线技术，本研究增强了增强的小小区上行链路和下行链路的波达方向和数字预失真技术。这项研究的基础是设计一个完全实现的、可编程的跨栈SDR平台，并集成可重构天线。该项目利用开源技术，将部署一个功能齐全的蜂窝主干系统，包括宏蜂窝基站和小蜂窝基站。该项目利用德雷克塞尔大学和WPI之间的合作，以及与奥卢大学、VTT技术研究中心和坦佩雷理工大学的强有力的国际合作。与芬兰机构的这一持续合作继续为本科生和研究生提供新颖的国际研究经验，并为传播开发的试验床进行试点测试。

The future proliferation of wireless systems and services is dependent on the design of flexible radio architectures that can adapt to the rapidly changing wireless environment. Since usable spectrum is limited, and modulation and coding techniques are approaching their Shannon capacity limitation, improving capacity through increased spectrum reuse and interference mitigation has become a high priority in future cellular networks. Industry leaders have focused on a multi-tiered heterogeneous network structure, where small-cell (e.g., pico-cell, femto-cell) base stations are deployed to meet capacity demand. Among the technical challenges making full-scale deployment of small-cell base stations possible, interference management still looms the largest. This project focuses on providing wireless systems with the available hardware and algorithmic tools to make intelligent decisions about antenna configuration for small-cell base stations to mitigate interference and improve network capacity and coexistence in a heterogeneous network environment.This project is composed of three main research thrusts: i.) Algorithm and System Design; ii.) Antenna and Transceiver Design; and iii.) Testbed Implementation. The first focus is on the mathematical modeling and overall system design of small-cell networks making use of reconfigurable antennas. A vital component of this overall system design is the development of efficient and effective analytical tools and algorithms for downlink transmission, focusing on directional network design, algorithms for directionality selection, and base station user association. The second thrust includes the development of practical reconfigurable antennas and transceiver processing techniques for small-cell base stations. The project team is adapting reconfigurable metamaterial and alford loop antenna designs to provide new, compact reconfigurable antenna architectures with both beam steering and variable beam width capabilities. Using these new antenna technologies this research enhances direction of arrival and digital pre-distortion techniques for enhanced small-cell uplink and downlink. The cornerstone of this research is the design of a fully implemented, programmable across-the-stack SDR platform with integrated reconfigurable antennas. This project makes use of open-source technologies and will result in the deployment of a fully functional cellular backbone system, consisting of both macro-cell and small-cell base stations.This project leverages collaboration between Drexel University and WPI, along with a strong international collaboration with the University of Oulu, VTT Technical Research Centre and Tampere University of Technology. This ongoing collaboration with Finnish institutions continues to provide novel international research experiences for undergraduate and graduate students as well as pilot testing for dissemination of the developed testbed.