Hierarchical Bandwidth Modulations for Ultra-Broadband Communications in the Terahertz Band
Hierarchical Bandwidth Modulations for Ultra-Broadband Communications in the Terahertz Band
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DOI：
10.1109/twc.2022.3207966
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发表时间：
2023-03-01
影响因子：
10.4
通讯作者：
Jornet, Josep M.
中科院分区：
文献类型：
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作者：
Bodet, Duschia;Sen, Priyangshu;Jornet, Josep M.
太赫兹（THz）波段（0.1-10 THz）通信将是实现高速无线链路的关键，因为可用带宽很宽。在太赫兹频率下，路径损耗由小天线孔径引起的高扩散损耗和水蒸气引起的分子吸收损耗决定。后者还决定了可用的传输带宽，它随着距离的缩小而缩小。为了充分利用THz信道的带宽，需要考虑高传播损耗和距离依赖带宽的调制。分层带宽调制（HBM）使用分层星座以符号速率同时服务用户，利用分子吸收来增加广播系统中的聚合数据速率，同时为经历高路径损耗的接收器提供灵活性。本文介绍了HBM并对其性能进行了评价。推导了4/M-QAM HBM系统的误符号率性能，并使用仿真进行了验证。这些结果用于定义HBM系统的设计约束：HBM功能区和过渡区。功能区进行了验证，使用超宽带通信的实验测试平台。结果表明，通过适当的设计，HBM成功地实现了其目标，利用太赫兹信道的距离相关特性，空间复用用户，并增加系统容量。
Terahertz (THz)-band (0.1-10 THz) communication will be key in enabling high speed wireless links due to the wide available bandwidths. At THz frequencies, the path-loss is governed by high spreading loss due to small antenna apertures and by molecular absorption loss due to water vapor. The latter also determines the available transmission bandwidth, which shrinks with distance. Modulations that consider the high propagation loss and the distance-dependent bandwidth are needed to fully exploit the THz channel's bandwidth. Using a hierarchical constellation to simultaneously service users at symbol rates, Hierarchical Bandwidth Modulation (HBM) leverages molecular absorption to increase aggregate data rates in a broadcast system while offering flexibility to receivers experiencing high path loss. This paper introduces HBM and evaluates its performance. The symbol error rate performance for a 4/M-QAM HBM system is derived and verified using simulations. These results are used to define the design constraints for an HBM system: the HBM functional region and transition region. The functional region is verified using an experimental testbed for ultrabroadband communications. The results show that with proper design HBM successfully achieves its goal to exploit the distance-dependent characteristics of the THz channel, to spatially multiplex users, and to increase the system capacity.