Searcharxiv⌕ Search

arXiv subjects

Adrian Kliks

Publications and source records attributed to Adrian Kliks.

At least 37 records · Page 2Linked to original sources

5G cellular systems supported by UAVs, RESs, and RISs (PL: Systemy komórkowe 5G wspierane przez BSP, OZE oraz IPR)

The paper considers energy consumption in 5G cellular networks powered by Renewable Energy Sources (RESs) and equipped with Reconfigurable Intelligent Surfaces (RISs) and tethered Unmanned Aerial Vehicles (UAVs), acting as mobile access points. The study was focused on the energy side of the Radio Access Network (RAN) located in the city of Poznań in Poland. The profit associated with the use of renewable energy generators, i.e. photovoltaic panels (PVP) for base stations (BSs) is presented in the form of two factors: the average number of UAV charges (ANUC) to provide continuous access to mobile services for connected user equipment (UE) terminals, and the average reduction in energy consumption (AREC) of the wireless system.

cs.NI↗

Wykorzystanie Rekonfigurowalnych Iinteligentnych Matryc Antenowych w Łączu Dosyłowym Sieci 5G/6G Wykorzystującej Bezzałogowe Statki Powietrzne

Drony, dzięki możliwości ich szybkiego rozmieszczenia w trudnym terenie, uważane są za jeden z kluczowych elementów systemów bezprzewodowych 6G. Jednak w celu wykorzystania ich jako punkty dostępowe sieci konieczne jest zapewnienie łącza dosyłowego o odpowiedniej przepustowości. Dlatego w niniejszym artykule rozważane jest zwiększenie zasięgu sieci bezprzewodowej przez zapewnienie łącza dosyłowego dla końcowego punktu dostępowego z wykorzystaniem określonej liczby dronów-przekaźników oraz rekonfigurowalnych inteligentnych matryc antenowych (RIS). Zaprezentowane wyniki badań symulacyjnych pokazują, że użycie RIS pozwala na znaczące zwiększenie zasięgu sieci bez konieczności stosowania dodatkowych przekaźników. -- Unmanned Aerial Vehicles, due to the possibility of their fast deployment, are considered an essential element of the future wireless 6G communication systems. However, an essential enabler for their use as access points is to provide a sufficient throughput wireless backhaul link. Thus, in this paper we consider the aspect of extension of network coverage with the use of drone-based relaying and reconfigurable intelligent surfaces (RIS) for backhauling. Presented results of simulation experiments indicate that the use of RIS allows for significant improvement of network coverage without the need to use additional relays.

cs.NI↗

Integrating UAV-Enabled Base Stations in 3D Networks: QoS-Aware Joint Fronthaul and Backhaul Design

The emerging concept of 3D networks, integrating terrestrial, aerial, and space layers, introduces a novel and complex structure characterized by stations relaying backhaul loads through point-to-point wireless links, forming a wireless 3D backhaul mesh. A key challenge is the strategic placement of aerial platform such as drone base stations (DBSs), considering the locations and service demands of ground nodes and the connectivity to backhaul gateway nodes for core network access. This paper addresses these complexities with a two-fold approach: a novel Agglomerative Hierarchical Clustering (HC) algorithm that optimizes DBS locations to satisfy minimum backhaul adjacency and maximum fronthaul coverage radius requirements; and a Genetic Algorithm (GA) that designs backhaul connections to satisfy the cumulative load across the network and maximize the throughput margin which translates to network resilience to increasing demands. Our results showcase the effectiveness of these algorithms against benchline schemes, offering insights into the operational dynamics of these novel 3D networks.

cs.NI↗

Energy Consumption in RES-Aware 5G Networks

In this work, the impact of using Renewable Energy Source (RES) generators in next-generation (5G) cellular systems on total power consumption (PC) has been investigated. The paper highlights the gain related to the use of photovoltaic (PV) panels and wind turbines (WTs) in the form of two factors - the average extension of battery lifetime (AEBL) powering a single network cell and the average reduction in energy consumption (AREC) within the whole network. The examination has been conducted for four different seasons of the year and various configurations of available power sources. The provided system scenario was based on real data on weather conditions, building placement, and implemented mobile networks for the city of Poznan in Poland. Used RES generators were designed in accordance with the specifications of real devices.

cs.NI↗

5G Networks Supported by UAVs, RESs, and RISs

This paper presents the examination of the 5G cellular network aware of Renewable Energy Sources (RESs) and supported by Reconfigurable Intelligent Surfaces (RISs) and Unmanned Aerial Vehicles working as mobile access nodes. The investigations have been focused on the energy side of the Radio Access Network (RAN) placed within the area of the city of Poznan (Poland). The gain related to enabling RES generators, i.e., photovoltaic (PV) panels, for base stations (BSs) was presented in the form of two factors -- the average number of UAV replacements (ANUR) with a fully charged one to ensure continuous access to mobile services for currently served user equipment (UE) terminals, and the average reduction in energy consumption (AREC) within the whole network.

cs.NI↗

Metamaterialy, konfigurowalne matryce antenowe i komunikacja holograficzna. Wstepna analiza nowej koncepcji bezprzewodowej transmisji danych

In the last few years, a very original concept of holographic communication has gained a lot of interest among scientists from all over the world. The specificity of this approach, on the one hand, is very different from the known and currently used solutions, on the other hand, it creates great development opportunities in the field of wireless communication. The article provides an overview of two technological solutions that gave rise to the idea of holographic communication. First, the possibility of using the so-called metamaterials for the purposes of wireless data transmission, and the second, the use of reconfigurable antenna surfaces. The last part presents the assumptions of the idea of holographic communication, in which the principles of creating images known from optical holography have been transferred to the radio band, and to some extend, generalized.

cs.ET↗

Wykorzystanie rekonfigurowalnych matryc antenowych wraz z informacją kontekstową

Reconfigurable intelligent surfaces can be successfully used to control the radio environment. Simple control of the reflection angle of the signal from the surface allows maximization or minimization of the received power in specific places. The paper presents simulations where it is possible to receive a signal in a place where it was not possible, to detect the occupancy of the spectrum in a place where the sensor was unable to make correct detection or to minimize interference in a specific receiver.

cs.NI↗

Machine Learning-based xApp for Dynamic Resource Allocation in O-RAN Networks

The disaggregated, distributed and virtualised implementation of radio access networks allows for dynamic resource allocation. These attributes can be realised by virtue of the Open Radio Access Networks (O-RAN) architecture. In this article, we tackle the issue of dynamic resource allocation using a data-driven approach by employing Machine Learning (ML). We present an xApp-based implementation for the proposed ML algorithm. The core aim of this work is to optimise resource allocation and fulfil Service Level Specifications (SLS). This is accomplished by dynamically adjusting the allocation of Physical Resource Blocks (PRBs) based on traffic demand and Quality of Service (QoS) requirements. The proposed ML model effectively selects the best allocation policy for each base station and enhances the performance of scheduler functionality in O-RAN - Distributed Unit (O-DU). We show that an xApp implementing the Random Forest Classifier can yield high (85\%) performance accuracy for optimal policy selection. This can be attained using the O-RAN instance state input parameters over a short training duration.

eess.SP↗

Open RAN xApps Design and Evaluation: Lessons Learnt and Identified Challenges

Open Radio Access Networks (RAN) offer diverse economic opportunities. A transition to a flexible, modular approach within the disaggregated RAN framework is crucial, involving careful planning of RAN architecture and the deployment of specialized software applications. Collaboration across sectors is essential for efficiency and reliability, with the open-source community driving innovation. This paper explores challenges for third-party application developers in Open RAN. It provides a comparative analysis of solutions, focusing on xApp development and implementation. Challenges arise in two areas: the complexities of xApp development, particularly for advanced use cases like beam management, and issues in low-level software implementation within open platforms. In conclusion, key challenges must promote academia-industry collaboration in Open RAN. This paper shares early lessons from xApp development, guiding the field's evolution.

cs.NI↗

Detection and mitigation of indirect conflicts between xApps in Open Radio Access Networks

In Open Radio Access Networks, the Conflict Mitigation component, which is part of the Near-RT RIC, aims to detect and resolve any conflicts between xApp decisions. In this paper, we propose a universal method for detecting and resolving of indirect conflicts between xApps. Its efficiency is validated by extensive computer simulations. Our results demonstrate that, in the considered scenario, the mean bitrate satisfaction of users increases by 2%, while the number of radio link failures and ping-pong handovers in the network is significantly reduced.

cs.NI↗

Conflict Mitigation Framework and Conflict Detection in O-RAN Near-RT RIC

The steady evolution of the Open RAN concept sheds light on xApps and their potential use cases in O-RANcompliant deployments. There are several areas where xApps can be used that are being widely investigated, but the issue of mitigating conflicts between xApp decisions requires further in-depth investigation. This article defines a conflict mitigation framework (CMF) built into the existing O-RAN architecture; it enables the Conflict Mitigation component in O-RAN's Near- Real-Time RAN Intelligent Controller (Near-RT RIC) to detect and resolve all conflict types defined in the O-RAN Alliance's technical specifications. Methods for detecting each type of conflict are defined, including message flows between Near-RT RIC components. The suitability of the proposed CMF is proven with a simulation of an O-RAN network. Results of the simulation show that enabling the CMF allows balancing the network control capabilities of conflicting xApps to significantly improve network performance, with a small negative impact on its reliability. It is concluded that defining a unified CMF in Near-RT RIC is the first step towards providing a standardized method of conflict detection and resolution in O-RAN environments.

cs.NI↗

Memory Enabled Bumblebee-based Dynamic Spectrum Access for Platooning Environments

In this paper, we propose a novel memory-enabled non-uniform sampling-based bumblebee foraging algorithm (MEB) designed for optimal channel selection in a distributed Vehicular Dynamic Spectrum Access (VDSA) framework employed in a platoon operating environment. Given how bumblebee behavioral models are designed to support adaptation in complex and highly time-varying environments, these models can be employed by connected vehicles to enable their operation within a dynamically changing network topology and support their selection of optimal channels possessing low levels of congestion to achieve high throughput. As a result, the proposed VDSA-based optimal channel selection employs fundamental concepts from the bumblebee foraging model. In the proposed approach, the Channel Busy Ratio (CBR) of all channels is computed and stored in memory to be accessed by the MEB algorithm to make the necessary channel switching decisions. Two averaging techniques, Sliding Window Average (SWA) and Exponentially Weighted Moving Average (EWMA), are employed to leverage past samples and are evaluated against the no-memory case. Due to the high variability of the environment (e.g., high velocities, changing density of vehicles on the road), we propose to calculate the CBR by employing non-uniform channel sampling allocations as well as evaluate it using both simplified numerical and realistic Vehicle-to-Vehicle (V2V) computer simulations. The numerical simulation results show that gains in the probability of the best channel selection can be achieved relative to a uniform sampling allocation approach. By utilizing memory, we observe an additional increase in the channel selection performance. Similarly, we see an increase in the probability of successful reception when utilizing the bumblebee algorithm via a system-level simulator.

cs.NI↗

Path Loss and Shadowing Modeling for Vehicle-to-Vehicle Communications in Terrestrial TV Band

Vehicle platooning is considered as one of the key use cases for vehicle-to-vehicle (V2V) communications. However, its benefits can be realized only with highly reliable wireless transmission. As the 5.9GHz frequency band used for V2V suffers from high congestion, in this paper, we consider the use of the terrestrial TV frequencies for intra-platoon communications. In order to be able to evaluate the potential of the new bands fully, propagation models for V2V communications at such frequencies are needed. Therefore, this paper reports new V2V propagation measurements and their modeling results. Particularly, we propose a Double Slope Double Shadowing model as the most accurate one, based on a comparison of various models using the Bayesian Information Criteria. We also investigate the space-time autocorrelation properties of the shadowing, which turned out to be dependent on the speed of vehicles. The proposed path loss and shadowing model differs from the ones proposed for the 5.9GHz band. Mostly, in favor of the TV band, as shown by, e.g., no statistically significant impact of a blocking car.

cs.NI↗

Federated Learning-Based Interference Modeling for Vehicular Dynamic Spectrum Access

A platoon-based driving is a technology allowing vehicles to follow each other at close distances to, e.g., save fuel. However, it requires reliable wireless communications to adjust their speeds. Recent studies have shown that the frequency band dedicated for vehicle-to-vehicle communications can be too busy for intra-platoon communications. Thus it is reasonable to use additional spectrum resources, of low occupancy, i.e., secondary spectrum channels. The challenge is to model the interference in those channels to enable proper channel selection. In this paper, we propose a two-layered Radio Environment Map (REM) that aims at providing platoons with accurate location-dependent interference models by using the Federated Learning approach. Each platoon is equipped with a Local REM that is updated on the basis of raw interference samples and previous interference model stored in the Global REM. The model in global REM is obtained by merging models reported by platoons. The nodes exchange only parameters of interference models, reducing the required control channel capacity. Moreover, in the proposed architecture platoon can utilize Local REM to predict channel occupancy, even when the connection to the Global REM is temporarily unavailable. The proposed system is validated via computer simulations considering non-trivial interference patterns.

cs.NI↗

Neural Networks for Path Planning

The scientific community is able to present a new set of solutions to practical problems that substantially improve the performance of modern technology in terms of efficiency and speed of computation due to the advancement in neural networks architectures. We present the latest works considering the utilization of neural networks in robot path planning. Our survey shows the contrast between different formulations of the problems that consider different inputs, outputs, and environments and how different neural networks architectures are able to provide solutions to all of the presented problems.

cs.AI↗

Distributed Learning for Vehicular Dynamic Spectrum Access in Autonomous Driving

Reliable wireless communication between the autonomously driving cars is one of the fundamental needs for guaranteeing passenger safety and comfort. However, when the number of communicating cars increases, the transmission quality may be significantly degraded due to too high occupancy radio of the used frequency band. In this paper, we concentrate on the autonomous vehicle-platooning use-case, where intra-platoon communication is done in the dynamically selected frequency band, other than nominally devoted for such purposes. The carrier selection is done in a flexible manner with the support of the context database located at the roadside unit (edge of wireless communication infrastructure). However, as the database delivers only context information to the platoons' leaders, the final decision is made separately by the individual platoons, following the suggestions made by the artificial intelligence algorithms. In this work, we concentrate on a lightweight Q-learning solution, that could be successfully implemented in each car for dynamic channel selection.

cs.NI↗

Radio Environment Maps for Dynamic Frequency Selection in V2X Communications

In this paper, we investigate the concept of database supported Vehicular Dynamic Spectrum Access (VDSA) for platooning. As various researchers show that the 5.9 GHz band, devoted for Intelligent Transportation Systems, may suffer from congestion of the channel, we propose to offload part of this traffic to white-spaces with the guidance of the active database system. In our work, we describe our measurement campaign which delivered data for population of the dedicated radio environment map. Once the map is created, it was used in three proposed algorithms for VDSA: an optimal and two pragmatic approaches.

cs.NI↗

Distributed Vehicular Dynamic Spectrum Access for Platooning Environments

In this paper, we propose a distributed Vehicular Dynamic Spectrum Access (VDSA) framework for vehicles operating in platoon formations. Given the potential for significant congestion in licensed frequency bands for vehicular applications such as 5.9 GHz. Our approach proposes to offload part of the intra-platoon data traffic to spectral white-spaces in order to enhance vehicular connectivity in support of on-road operations. To enable VDSA, a Bumblebee-based decision making process is employed which is based on the behavioral models of animals, is employed to provide a means of distributed transmission band selection. Simulation results show the distributed VDSA framework improves the leader packets reception ratio by 5%, thus indicating its potential to increase in reliability of intra-platoon communications.

cs.NI↗