Abstract-Wireless Terahertz System Architectures for Networks Beyond 5G

Alexandros-Apostolos A. Boulogeorgos, Angeliki Alexiou, Dimitrios Kritharidis, Alexandros Katsiotis, Georgia Ntouni, Joonas Kokkoniemi, Janne Lethtomaki, Markku Juntti, Dessy Yankova, Ahmed Mokhtar, Jean-Charles Point, Jose Machado, Robert Elschner, Colja Schubert, Thomas Merkle, Ricardo Ferreira, Francisco Rodrigues, Jose Lima

https://arxiv.org/abs/1810.12260

The present white paper focuses on the system requirements of TERRANOVA. Initially details the key use cases for the TERRANOVA technology and presents the description of the network architecture. In more detail, the use cases are classified into two categories, namely backhaul & fronthaul and access and small cell backhaul. The first category refers to fibre extender, point-to-point and redundancy applications, whereas the latter is designed to support backup connection for small and medium-sized enterprises (SMEs), internet of things (IoT) dense environments, data centres, indoor wireless access, ad hoc networks, and last mile access. Then, it provides the networks architecture for the TERRANOVA system as well as the network elements that need to be deployed. The use cases are matched to specific technical scenarios, namely outdoor fixed point-to-point (P2P), outdoor/indoor individual point-to-multipoint (P2MP), and outdoor/indoor "quasi"-omnidirection, and the key performance requirements of each scenario are identified. Likewise, we present the breakthrough novel technology concepts, including the joint design of baseband signal processing for the complete optical and wireless link, the development of broadband and spectrally efficient RF-frontends for frequencies >275 GHz, as well as channel modelling, waveforms, antenna array and multiple-access schemes design, which we are going to use in order to satisfy the presented requirements. Next, an overview of the required new functionalities in both physical (PHY) layer and medium access control (MAC) layers in the TERRANOVA system architecture will be given. Finally, the individual enablers of the TERRANOVA system are combined to develop particular candidate architectures for each of the three technical scenarios.

Abstract-Last Meter Indoor Terahertz Wireless Access: Performance Insights and Implementation Roadmap

Vitaly Petrov,  Joonas Kokkoniemi, Dmitri Moltchanov, Janne Lehtomaki,  Yevgeni Koucheryavy,  Markku Juntti,

https://ieeexplore.ieee.org/document/8387220/

The terahertz band, 0.1-10 THz, has sufficient resources not only to satisfy the 5G requirements of 10 Gb/s peak data rate but to enable a number of tempting rate-greedy applications. However, the terahertz band brings novel challenges, never addressed at lower frequencies. Among others, the scattering of terahertz waves from any object, including walls and furniture, and ultra-wideband highly directional links lead to fundamentally new propagation and interference structures. In this article, we review the recent progress in terahertz propagation modeling, and antenna and testbed designs, and propose a step-by-step roadmap for wireless terahertz Ethernet extension for indoor environments. As a side effect, the described concept provides a second life to the currently underutilized Ethernet infrastructure by using it as a universally available backbone. By applying real terahertz band propagation, reflection, and scattering measurements as well as ray-tracing simulations of a typical office, we analyze two representative scenarios at 300 GHz and 1.25 THz frequencies, illustrating that extremely high rates can be achieved with realistic system parameters at room scales.

Abstract- A Causal Channel Model for the Terahertz Band

Kazuhiro Tsujimura,  Kenta Umebayashi, Joonas Kokkoniemi,  Janne Lehtomäki,  Yasuo Suzuki

https://ieeexplore.ieee.org/document/8123513/

Impulse response is vital for wireless communication analysis and modeling. This paper considers the impulse response of the terahertz band (THz band: 0.1-10 THz) for short range (1-100 cm) wireless communication. Earlier works derived the impulse response from transmittance by assuming a linear phase, which corresponds to a line-of-sight (LoS) propagation delay to a receiver. However, the linear phase leads to a symmetric impulse response before and after the LoS propagation delay. Physically, it is impossible for a signal to arrive before the LoS propagation delay since this violates causality. To address this issue, this study derives a phase function leading to an impulse response that satisfies causality. The validity of the derived model is verified with experimental THz band measurements (up to 2 THz), which show excellent agreement with the results predicted by the theory. From the impulse response, coherence bandwidth is found for both the entire THz band and its subbands. The results show significant variations in the coherence bandwidth as a function of the center frequency. Knowledge of these variations supports selection of the proper center frequency for wireless communications in the THz band.

Abstract-The Impact of Interference from the Side Lanes on mmWave/THz Band V2V Communication Systems with Directional Antennas

Vitaly Petrov, Joonas Kokkoniemi, Dmitri Moltchanov, Janne Lehtomaki, Markku Juntti, Yevgeni Koucheryavy,

http://ieeexplore.ieee.org/abstract/document/8272491/

Communications systems operating in the millimeter and terahertz band have been recently suggested to enable high data-rate vehicle-to-vehicle communications in future networks. However, massive deployment of such systems may lead to significant interference, affecting the performance of information transmission. While the multipath interference caused by the signal reflections from the road has been extensively discussed in literature, the interference caused by the vehicles on the side lanes has been insufficiently studied so far. In this paper, using a combination of measurement, simulation, and analytical methods we comprehensively characterize the interference from the side lanes in two typical deployments including highway and urban road environments for millimeter and low terahertz bands. Both the multipath interference and direct interference from the transmitting vehicles on the side lanes are taken into account. As a result of the presented study, we reveal that: i) the interference from the side lanes can be well approximated using two-dimensional stochastic models without any notable loss of accuracy; and ii) even when highly directional antennas are used there are special spatial configurations, where the interference may greatly affect the communication systems performance. We lately apply the developed models to estimate the signal-to-interference ratio and link capacity of mmWave/THz band V2V communications with directional antennas.