EARS: Achieving Spectrum Efficient Broadcast Under Cross-Technology Interference

无线技术已经渗透到人们的日常生活中，用于个人通信、移动上网、全球定位、数字媒体广播、智能家居自动化等。这些技术部署在各种环境中，从控制良好的实验室和住宅到高度动态的城市环境。这项工作旨在改进一系列无线技术，以便在高度拥挤的WiFi、蓝牙和LTE环境中更可靠、更快速、更经济地传播信息。研究表明，重叠信道中不协调的无线共存导致频谱利用效率严重低下。虽然最近已经有一些共存设计来处理跨技术干扰（CTI），但这些研究主要集中在提高单播通信的频谱利用率上。与一对一单播通信不同，一对多广播通信的网络拓扑特征对广播频谱效率影响较大。随着对广播支持需求的不断增加，迫切需要对无线共存环境下的广播频谱效率进行研究。本项目对CTI下的广播进行了系统的跨层研究，提供了跨物理层、数据链路层和网络层的新颖设计。研究课题包括：1)开展广泛的测量研究，收集各种环境中有关交叉技术干扰模式的痕迹；2)建立综合模型，将测量轨迹的实例概括为一组参数化模型，精确表征跨技术干扰的特征；3)对不受控制的CTI如何同时影响多个无线链路进行了实证和理论建模，并通过网络拓扑管理提出了缓解方法；4)提供一个空间、时间和频谱的CTI映射设备，将CTI信息作为一种服务暴露给周围的无线ISM设备，使这些设备能够在空间、时间和频谱域中寻找空白机会进行有效广播；5)通过跨技术调制嵌入侧信道信息，支持跨技术广播。这项工作的广泛影响通过以下方式得以扩大：(i)通过加强课程项目来改善课程发展；（ii）通过高知名度的教程和开源网站传播研究成果；（iii）通过开放日提高K-12学生和少数族裔对科技的兴趣；（四）支持优秀女、少数民族博士生顺利完成博士学业。

Wireless technologies have percolated into people's daily life for personal communication, mobile Internet surfing, global positioning, digital media broadcasting, and smart home automation. These technologies are deployed in environments ranging from well-controlled laboratories and residential houses to highly dynamic urban surroundings. This work aims at improving a range of wireless technologies so that information can be broadcast more reliably, quickly and cost-efficiently in highly crowded WiFi, Bluetooth and LTE environments. Research has shown that uncoordinated wireless coexistence in overlapping channels leads to severe inefficiency in spectrum utilization. Although a few coexistence designs have been done recently to deal with cross-technology interference (CTI), those studies focus primarily on improving spectrum utilization in unicast communication. Unlike in one-to-one unicast communication, network topological features in one-to-many broadcast communication significantly impact broadcast spectrum efficiency. With the increasing demand for broadcast support, the field is facing an urgent need to investigate broadcast spectrum efficiency in the context of wireless coexistence.This project conducts a systematic cross-layer study of broadcast under CTI, contributing novel designs across physical, data link, and network layers. The research topics include: 1) conducting extensive measurement studies to collect traces regarding cross-technology interference patterns in a wide range of environments; 2) building synthetic models to generalize instances of measure traces into a set of parameterized models that precisely characterize features of cross-technology interference; 3) empirically and theoretically modeling how uncontrolled CTI affects multiple wireless links simultaneously and proposing mitigation methods through network topology management; 4) delivering a spatial, temporal, and spectral CTI mapping device that exposures CTI information as a service to surrounding wireless ISM devices, so that these devices can seek white space opportunities in spatial, temporal and spectral domains for effective broadcast, and 5) supporting cross-technology broadcast by embedding side-channel information through cross-technology modulation. The broader impact of this work is amplified by (i) improving curriculum development with enhanced course projects; (ii) disseminating research results through high-profile tutorials and open-source sites; (iii) raising interest in technology among K-12 students and under-represented minority groups through open houses; and (iv) supporting talented female and minority PhD students to successfully accomplish their doctoral studies.