Massive MIMO Channel Sounder for Sub-THz Based on Virtual Array Concept

The sub-THz frequency spectrum ranging from 90 GHz to 300 GHz offers huge untapped frequency band, up to several tens of GHz, which is highly promising forachieving extremely high data rate transmission. Therefore, sub-THz technology is considered as one of the key technology candidates for beyond 5G communication systems. However, sub-THz communication relies on dominant propagation path in the environments. It is essential to identify and track thedominant paths in the channel to maintain the communication link. Understanding the spatial profiles of the channel is therefore essential. In this work, we present a long range sub-THz channel sounder we developed at Aalborg University Denmark, which is capable of capturing the spatial profile of the channel with high spatial resolution based on the virtual array concept. The channel sounder is experimentally validated in field measurements

Confinement effects from interacting chromo-magnetic and axion fields

We study a non-Abelian gauge theory with a pseudo scalar coupling \phi \epsilon ^{\mu \nu \alpha \beta} F_{\mu \nu}^a F_{\alpha \beta}^a in the case where a constant chromo-electric, or chromo-magnetic, strength expectation value is present. We compute the interaction potential within the framework of gauge-invariant, path-dependent, variables formalism. While in the case of a constant chromo-electric field strength expectation value the static potential remains Coulombic, in the case of a constant chromo-magnetic field strength the potential energy is the sum of a Coulombic and a linear potentials, leading to the confinement of static charges.Comment: 12 pages, no figures, published versio

Adaptable Value-Set Analysis for Low-Level Code

This paper presents a framework for binary code analysis that uses only SAT-based algorithms. Within the framework, incremental SAT solving is used to perform a form of weakly relational value-set analysis in a novel way, connecting the expressiveness of the value sets to computational complexity. Another key feature of our framework is that it translates the semantics of binary code into an intermediate representation. This allows for a straightforward translation of the program semantics into Boolean logic and eases the implementation efforts, too. We show that leveraging the efficiency of contemporary SAT solvers allows us to prove interesting properties about medium-sized microcontroller programs

Measuring the Interference at an RFID Tag: Where Does It Have an Impact?

In this paper we consider reader collisions in an RFID system, especially how interference impacts the ability of a passive UHF tag to respond. We propose two innovative applications for using interference: 1) Blocking a tag response, and 2) cooperative reading of a tag. In order to investigate their applicability we focus on the experimental evaluation, where we impose interference on the download and uplink, respectively, and on both links simultaneously. The results are positive with respect to blocking the tag, where modulated Co-Channel Interference shows most effective. Based on the measurements it is however not possible to read a tag cooperatively, i.e. the tag is unable to utilize the interference as an additional energy source

METAMOC: Modular Execution Time Analysis using Model Checking

Safe and tight worst-case execution times (WCETs) are important when scheduling hard real-time systems. This paper presents METAMOC, a path-based, modular method, based on model checking and static analysis, that determines safe and tight WCETs for programs running on platforms fea-turing caching and pipelining. The method works by constructing a UPPAAL model of the program being analysed and annotating the model with information from an inter-procedural value analysis. The program model is then combined with a model of the hardware platform, and model checked for the WCET. Through support for the platforms ARM7, ARM9 and ATMEL AVR 8-bit the modularity and retargetability of the method is demonstrated, as only the pipeline needs to be remodelled. Mod-elling the hardware is performed in a state-of-the-art graphical modeling environment. Experiments on the Mälardalen WCET benchmark programs show that taking caching into account yields much tighter WCETs, and that METAMOC is a fast and versatile approach for WCET analysis. 1