CRII: NeTS: Towards the Design of a Large-Scale Wireless Sensor Network

该项目的目标是设计高度可扩展的无线传感器网络（WSNs）的传感和控制应用在广阔的区域。由于新兴的广域无线监视和控制系统（例如，城市传感、大型民用基础设施监控、油田管理），需要长距离连接数千个传感器。由于其短的通信范围，现有的无线传感器网络技术面临着能源，成本和复杂性方面的关键挑战，以实现广域部署的可扩展性。为了解决这个问题，该项目提出了一个可扩展的传感器网络架构-称为传感器网络在白色空间（SNOW）-通过设计传感器网络在电视白色空间，这是指分配，但未使用的电视频道。该项目将导致新一代的无线传感器网络，将运行在白色空间，使广泛的应用，涉及广域监测和控制。除了对计算机科学的多个子领域产生科学影响外，它还将影响教育，推广和多样性。该项目的科学贡献将纳入各种计算机科学课程。拟议的研究和动手实验机会的跨学科性质将吸引不同的学生参加该项目，包括妇女和代表性不足的学生。首席研究员（PI）将利用与工业合作伙伴的合作，将技术转移到未来的WSN微尘设计行业，并将与标准机构合作，标准化该项目中开发的技术。由于TV传输是在较低频率（50-698 MHz），所以白色空间在长距离上具有优良的传播特性。与ISM频段相比，它们不那么拥挤。长距离将使大多数无线传感器网络减少到单跳结构，这有可能减少在2.4GHz下运行的现有无线传感器网络技术由于多跳而面临的复杂性、开销和延迟。因此，SNOW可以支持大规模的传感器部署。然而，大多数无线传感器网络应用需要低数据速率，低功率节点，并要求可扩展性和能源效率。SNOW架构通过信道分割和支持单个无线电同时接收数据包来实现可扩展性和能效。基站功率丰富，并且具有使用来自白色空间的可用宽频谱的单个收发器。频谱被分成具有较长范围且消耗较少功率的窄子载波。传感器节点异步地使用其分配的子载波进行传输。基站能够同时处理多个子载波。在节点处实现这种同时接收是具有挑战性的，因为它需要新颖的解码器设计。在SNOW架构中，这是通过提供不同正交信号的正交频分复用（OFDM）来完成的。本项目的贡献包括：（1）SNOW物理层的设计，包括白色空间频谱分解成窄带子载波和解调器设计，可以解码同时接收的分组：（2）SNOW媒体访问控制协议的设计，处理子载波在节点之间的分配和它们的传输调度;（3）在原型硬件上实现了SNOW体系结构，并通过实际实验进行了评估。

The objective of this project is to design highly scalable wireless sensor networks (WSNs) for sensing and control applications over wide areas. WSNs face significant scalability challenges due to the proliferation of emerging wide-area wireless monitoring and control systems (e.g., urban sensing, large civil infrastructure monitoring, oil field management) that require thousands of sensors be connected over long distances. Due to their short communication range, existing WSN technologies face critical challenges in terms of energy, cost, and complexity to achieve scalability in wide-area deployments. To address this limitation, this project proposes a scalable sensor network architecture - called Sensor Network Over White Spaces (SNOW) - by designing sensor networks to operate over the TV white spaces, which refer to the allocated but unused TV channels. This project will lead to a new generation of WSN that will operate over white spaces, enabling a broad range of applications that involve wide-area monitoring and control. Besides its scientific impact across multiple subareas of computer science, it will impact education, outreach, and diversity. The scientific contributions of the project will be incorporated in various computer science courses. The interdisciplinary nature of the proposed research and hands-on experimental opportunities will attract diverse students to participate in the project including women and under-represented students. The principal investigator (PI) will leverage collaborations with industrial partners to transfer the technology to industries for future WSN mote design and also will work with standards bodies to standardize the technology to be developed in this project. Since the TV transmissions are in lower frequencies (50-698 MHz), white spaces have excellent propagation characteristics over long distances. Compared to the ISM band, they are less crowded. Long range will reduce most WSNs to a single-hop structure that has potential to reduce the complexity, overhead, and latency that existing WSN technologies operating in 2.4GHz face due to multi-hop. SNOW hence can support large-scale sensor deployments over wide areas. However, most WSN applications need low data rate, low power nodes, and require scalability and energy efficiency. The SNOW architecture achieves scalability and energy efficiency through channel splitting and enabling simultaneous packet receptions with single radio. The base station is power-rich and has a single transceiver that uses available wide spectrum from white spaces. The spectrum is split into narrow subcarriers that have longer range and that consume less power. The sensor nodes transmit using their assigned sub-carriers asynchronously. The base station is able to process multiple sub-carriers simultaneously. Enabling such simultaneous receptions at a node is challenging as it requires a novel decoder design. In the SNOW architecture, this is done through Orthogonal Frequency Division Multiplexing (OFDM) that provides distinct orthogonal signals. The contributions of this project will include: (1) the design of the physical layer of SNOW that includes white space spectrum splitting into narrow band subcarriers and a demodulator design that can decode simultaneous packet receptions; (2) the design of the media access control protocol for SNOW that handles subcarrier allocation among the nodes and their transmission scheduling; (3) the implementation of the SNOW architecture on a prototype hardware, and evaluation through realistic experiments.