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

本项目的目标是设计高度可扩展的无线传感器网络(WSNs)，用于大范围的传感和控制应用。由于新兴的广域无线监测和控制系统(例如，城市传感、大型民用基础设施监测、油田管理)的激增，无线传感器网络面临着巨大的可扩展性挑战，这些系统需要数千个传感器进行长距离连接。由于通信距离短，现有的无线传感器网络技术在实现广域部署的可扩展性方面面临着能源、成本和复杂性方面的严峻挑战。为了解决这一局限性，本项目提出了一种可扩展的传感器网络体系结构-称为白色空间传感器网络(SNOW)-通过设计传感器网络在电视白色空间上运行，这些白色空间指的是已分配但未使用的电视频道。该项目将带来新一代无线传感器网络，它将在空白空间运行，实现涉及广域监控的广泛应用。除了它对计算机科学多个子领域的科学影响外，它还将影响教育、推广和多样性。该项目的科学贡献将被纳入各种计算机科学课程。拟议研究的跨学科性质和动手实验机会将吸引不同的学生参加该项目，其中包括妇女和代表性不足的学生。首席研究员(PI)将利用与行业合作伙伴的合作，将技术转移到行业，用于未来的WSN微尘设计，并将与标准机构合作，使该项目中开发的技术标准化。由于电视传输的频率较低(50-698 MHz)，因此空白区域具有良好的远距离传播特性。与ISM乐队相比，他们不那么拥挤。长距离将把大多数无线传感器网络减少到单跳结构，这可能会降低现有的工作在2.4 GHz的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可以支持在大范围内大规模部署传感器。然而，大多数无线传感器网络应用需要低数据速率、低功耗的节点，并且需要可扩展性和能量效率。SNOW架构通过信道拆分和支持使用单个无线电同时接收分组来实现可伸缩性和能源效率。基站功率丰富，只有一个收发机，可以从空白区域使用可用的宽频谱。频谱被分成几个窄的子载波，这些子载波具有更长的范围和更低的功率消耗。传感器节点使用其分配的子载波进行异步传输。基站能够同时处理多个子载波。在一个节点实现这样的同时接收是具有挑战性的，因为它需要新的解码器设计。在Snow架构中，这是通过提供不同正交信号的正交频分多路复用(Ofdm)来实现的。本项目的主要贡献包括：(1)设计了包括分成多个窄带子载波的空白频谱的雪花物理层，并设计了能够同时解码分组接收的解调器；(2)设计了处理节点之间的子载波分配和传输调度的雪花媒体接入控制协议；(3)在原型硬件上实现了雪花体系结构，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.