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-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.

Abstract-Analytical approximations for interference and SIR densities in terahertz systems with atmospheric absorption, directional antennas and blocking

Dmitri Moltchanov, Pavel Kustarev, Yevgeni Koucheryavy,

https://www.sciencedirect.com/science/article/pii/S1874490717301702

Researchers face fundamental challenges applying the stochastic geometry framework to analysis of terahertz (THz) communications systems. The two major problems are the principally new propagation model that now includes exponential term responsible for molecular absorption and blocking of THz radiation by the human crowd around the receiver. These phenomena change the probability density function (pdf) of the interference from a single node such that it no longer has an analytical Laplace transform (LT) preventing characterization of the aggregated interference and signal-to-interference ratio (SIR) distributions. The expected use of highly directional antennas at both transmitter and receiver adds to this problem increasing the complexity of modeling efforts. In this paper, we consider Poisson deployment of interferers in ${\Re }^2$ and provide accurate analytical approximations for pdf of interference from a randomly chosen node for blocking and non-blocking cases. We then derive LTs of pdfs of aggregated interference and SIR. Using the Talbot’s algorithm for inverse transform we provide numerical results indicating that failure to capture atmospheric absorption, blocking or antenna directivity leads to significant modeling errors. Finally, we investigate the response of SIR densities to a wide range of system parameters highlighting the specific effects of THz communications systems. The model developed in this paper can be used as a building block for performance analysis of realistic THz network deployments providing metrics such as outage and coverage probabilities.

Abstract-Terahertz Band Intra-Chip Communications: Can Wireless Links Scale Modern x86 CPUs?

Terahertz band communications is a promising enabler technology for Wireless-Networks-on-Chip. However, the backward compatibility issues appear when considering the massive production. Motivated by this, we proposed a novel 3D x86-compatible CPU architecture with THz assisted wireless links between the cores and the shared cache. Our cross-disciplinary analysis reveals that up to 200 cores can be supported by the THz-enabled wireless-network-on-chip

Vitaly Petrov, Dmitri Moltchanov, Maria Komar, Alexander Antonov,  Pavel Kustarev, Shaloo Rakheja,   Yevgeni Koucheryavy

http://ieeexplore.ieee.org/document/7891056/

Massive multi-core processing has recently attracted significant attention from the research community as one of the feasible solutions to satisfy constantly growing performance demands. However, this evolution path is nowadays hampered by the complexity and limited scalability of bus-oriented intra-chip communications infrastructure. The latest advantages of terahertz (THz) band wireless communications providing extraordinary capacity at the air interface offer a promising alternative to conventional wired solutions for intra-chip communications. Still, to invest resources in this field manufacturers need a clear vision of what are the performance and scalability gains of wireless intra-chip communications. Using the comprehensive hybrid methodology combining THz ray-tracing, direct CPU traffic measurements, and cycle-accurate CPU simulations, we perform the scalability study of x86 CPU design that is backward compatible with the current x86 architecture. We show that preserving the current cache coherence protocols mapped into the star wireless communications topology that allows for tight centralized medium access control a few hundreds of active cores can be efficiently supported without any notable changes in the x86 CPU logic. This important outcome allows for incremental development, where THz-assisted x86 CPU with a few dozens of cores can serve as an intermediate solution, while the truly massive multi-core system with broadcast-enabled medium access and enhanced cache coherence protocols can be an ultimate goal.