NeTS: Small: Collaborative Research: Fine-Grained Spectrum Access for Carrier-Aggregation Based Wireless Networks

动态频谱接入为过度拥挤的无线电频谱中的用户带来了巨大的好处，以机会主义地收获频谱资源，这对于诸如视频会议和多媒体流之类的高数据速率应用特别有用。由于可用频谱可能是分段的，因此载波聚合成为关键的使能技术。许多最近和新兴的协议（例如，802.11ac WiFi、802.11af TV空白空间网络、3GPP LTE未授权和802.11ay毫米波网络）已经并入载波聚合机制。然而，这些机制仍然是初步的，并且严重依赖于传统的MAC/PHY，其被设计用于共享相同的连续信道的节点。随着载波聚合网络向新一代演进，三个固有问题将成为其效率、公平性和可扩展性的根本障碍：（i）发射机无法在传输期间感测介质状态，（ii）更多用户和高频谱动态恶化介质接入竞争，以及（iii）需要快速频谱协议来聚合多个碎片化频谱块。本研究的目标是探索有效实现载波聚合的一般原语，包括三个研究部分：（i）将频谱感知范式从“检测然后发送”迁移到“同时发送和检测”。最终目标是克服标准频谱感知机制中的效率和公平性问题，以实现异步、带外OFDM频谱感知和基于多天线的全双工感知。(ii)以低冲突概率和低开销解决宽带分段频谱共享中的竞争问题。提出了一种频谱仲裁机制，通过并行逐位信令方案和新颖的复合分组前导码设计来实现。(iii)设计一种轻量级的带内机制，实现快速同步和频谱协商，以克服在高频谱动态下用于频谱协商的大量控制信道开销。拟议研究的成功将增强无线电频谱共享，并激励标准化机构将拟议的新协议原语纳入更高的性能。将继续努力将拟议的研究纳入教育方案，指导本科研究人员，并招收妇女和少数民族学生。

Dynamic spectrum access brings great benefits for users in overcrowded radio spectrum to opportunistically harvest spectrum resources, which is especially useful for high date rate applications such as video conferencing and multimedia streaming. Since available spectrum may be fragmented, carrier aggregation becomes a critical enabling technique. Many recent and emerging protocols (e.g., 802.11ac WiFi, 802.11af TV whitespace networks, 3GPP LTE unlicensed, and 802.11ay millimeter-wave networks) have been incorporating carrier aggregation mechanisms. However, these mechanisms are still preliminary and heavily rely on conventional MAC/PHY which is designed for nodes sharing the same contiguous channel. As carrier aggregation networks evolve to new generations, three inherent problems will become the fundamental barrier to their efficiency, fairness, and scalability: (i) a transmitter is unable to sense medium state during transmission, (ii) more users and high spectrum dynamics worsen the medium access contention, and (iii) the need of fast spectrum agreement to aggregate multiple fragmented spectrum chunks. The objective of this research is to explore general primitives to effectively realize carrier aggregation with three research components: (i) Migrate the spectrum sensing paradigm from "detect and then transmit" to "simultaneously transmit and detect". The end goal is to overcome the efficiency and fairness problems in standard spectrum sensing mechanisms to enable asynchronous, out-of-band OFDM spectrum sensing and multi-antenna based full-duplex sensing. (ii) Address the contention issue in wideband fragmented spectrum sharing with low collision probabilities and low overhead. A spectrum arbitration mechanism is proposed, enabled by a parallel bitwise signaling scheme and a novel compound packet preamble design. (iii) Design a light-weight in-band mechanism that achieves fast synchronization and spectrum agreement, so as to overcome the substantial control channel overhead for spectrum agreement under high spectrum dynamics. The success of the proposed research will enhance radio spectrum sharing, and inspire standardization bodies to incorporate the proposed new protocol primitives for much higher performance. A continuous effort will be made to integrate the proposed research to education program, to mentor undergraduate researchers, and recruit women and minority students.