Wi-Fi HaLow offers promising capabilities for handling heterogeneous traffic in Internet of Things environments through its high throughput and built-in scheduled access mechanisms, including Restricted Access Window (RAW) and Target Wake Time (TWT), which save energy and avoid collisions. However, most existing devices do not support such mechanisms, which significantly limits the performance of Wi-Fi HaLow networks. An alternative solution is to implement software-based scheduled access at the application level, i.e., make an application responsible for scheduled data transmission. Correct operation of software-based scheduling requires knowledge of possible latencies caused by data processing and Medium Access Control (MAC) layer random access mechanisms. In this paper, we tackle this problem and study latencies for the Software-Based RAW (SB-RAW) mechanism for scheduled data transmissions. Based on that, we estimate the minimum guard interval between scheduled transmissions using Wi-Fi HaLow devices. Our findings provide practical guidelines for SB-RAW usage in Wi-Fi HaLow networks, particularly for applications with various traffic requirements.

The 5G millimeter wave (mmWave) New Radio (NR) systems are prone to blockage and micromobility effects. To improve service reliability, 3GPP proposed a dual-connectivity allowing UE to maintain links to two base stations (BS). However, this functionality is power-hungry resulting in a trade-off between performance and power efficiency. In this paper, we compare user equipment (UE) power efficiency, consumption, and battery lifetime for different intra- and inter-radio access technologies single- and dual-connectivity under different UE usage scenarios, micromobility, and blockage impairments. We evaluate five schemes: (i) BSs in FR1 and FR2 bands (NR-DC FR1/FR2), (ii) BSs in FR2 band (NR-DC FR2/FR2), and (iii) LTE BS and NR BS in FR2 band (EN-DC LTE/FR2), (iv) NR FR1, and (iv) LTE. Our results show that the LTE-only scheme provides three times longer battery lifetime as compared to its nearest rival-NR FR1 single-connectivity option. For dual-connectivity options, the best lifetime is observed for EN-DC FR2/LTE, and the worst – for NR-DC FR2/FR1. The difference between NR-DC FR2/FR1 and NR-DC FR2/FR2 schemes is negligible. Densification negatively affects all the dual-connectivity schemes as it forces UEs to switch between master and backup technologies more often. We recommend EN-DC FR2/LTE for low-traffic outage-sensitive applications, while NR-DC FR2/FR2-for heavy-traffic outage non-sensitive applications.

The paper addresses the problem of reverse engineering a function block (FB) in situations when its source code is either not available or is too complex to understand. The proposed approach builds up on a recent method for reconstructing FBs based on testing and a search-based optimization algorithm. In our work the method is augmented with candidate solution verification using the NuSMV model checker. Verification is done in a closed-loop way using a manually constructed surrogate model of the plant and environment.

Nekbone is a proxy application of Nek5000, a scalable Computational Fluid Dynamics (CFD) code used for modelling incompressible flows. The Nekbone mini-application is used by several international co-design centers to explore new concepts in computer science and to evaluate their performance. We present the design and implementation of a new communication kernel in the Nekbone mini-application with the goal of studying the performance of different parallel communication models. First, a new MPI blocking communication kernel has been developed to solve Nekbone problems in a three-dimensional Cartesian mesh and process topology. The new MPI implementation delivers a 13% performance improvement compared to the original implementation. The new MPI communication kernel consists of approximately 500 lines of code against the original 7,000 lines of code, allowing experimentation with new approaches in Nekbone parallel communication. Second, the MPI blocking communication in the new kernel was changed to the MPI non-blocking communication. Third, we developed a new Partitioned Global Address Space (PGAS) communication kernel, based on the GPI-2 library. This approach reduces the synchronization among neighbor processes and is on average 3% faster than the new MPI-based, non-blocking, approach. In our tests on 8,192 processes, the GPI-2 communication kernel is 3% faster than the new MPI non-blocking communication kernel. In addition, we have used the OpenMP in all the versions of the new communication kernel. Finally, we highlight the future steps for using the new communication kernel in the parent application Nek5000.