Papers by Darya Ostrikova
IEEE Transactions on Wireless Communications
IEEE Transactions on Wireless Communications, 2023
Mathematics, Dec 21, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
IEEE Communications Letters
2017 9th International Congress on Ultra Modern Telecommunications and Control Systems and Workshops (ICUMT), 2017
This paper proposes an analytical model for characterizing the impact of the users' mobility ... more This paper proposes an analytical model for characterizing the impact of the users' mobility in the multicast subgroup formation problem when the aggregate data rate is maximized in Long Term Evolution (LTE) and beyond systems. We demonstrate that, under the condition of constant number of multicast users within the service area, their mobility can be modelled as a queuing network. The proposed model has been validated with the most relevant multicast mobility simulative approaches proposed in literature. The high relevance of this result is that the proposed model can be easily exploited to characterize the user mobility in practical LTE systems to avoid the heavy-processing burden of solutions based on simulative approaches.
2021 IEEE Global Communications Conference (GLOBECOM), 2021
Terahertz (THz) band is considered as the main candidate for new radio access technology in sixth... more Terahertz (THz) band is considered as the main candidate for new radio access technology in sixth-generation (6G) cellular systems. However, the performance of these systems will be severely affected by not only blockage but user equipment (UE) micromobility in hands of a user. The negative effects of these phenomena can be alleviated by utilizing the multi-connectivity functionality that allows UE to maintain two or more links to nearby base stations (BS) and use them when the currently active link is lost. By accounting for THz specific propagation, antenna and beamsearching design, the density of THz BS deployment, and multi-connectivity operation, we investigate the successful session completion probability under both types of impairments. Our results indicate that the gains of multi-connectivity are observed up to 5 simultaneously supported links and heavily depend on the application outage tolerance time and is mostly affected by micromobility. To improve it, one needs to ensure that the application may tolerate outage caused by beamsearching time which is on the order of milliseconds.
Vitalii A. Beschastnyi*, Darya Yu. Ostrikova*, Alexander I. Zeifman†‡, Irina. A. Gudkova*S * Depa... more Vitalii A. Beschastnyi*, Darya Yu. Ostrikova*, Alexander I. Zeifman†‡, Irina. A. Gudkova*S * Department of Applied Probability and Informatics Peoples’ Friendship University of Russia (RUDN University) 6 Miklukho-Maklaya St, Moscow, 117198, Russian Federation † Department of Applied Mathematics Vologda State University 6 Orlova St, Vologda, 160000, Russian Federation ‡ Institute of Informatics Problems Federal Research Center "Computer Science and Control" of the Russian Academy of Sciences 44-2 Vavilov St, Moscow, 119333, Russian Federation S Faculty of Electrical Engineering and Communication Brno University of Technology 3058/10 Technická, 61600 Brno, Czech Republic
The preparation and properties of tris-methylmercury-oxonium fluoborate (CH 3 Hg):i0BF 4 are desc... more The preparation and properties of tris-methylmercury-oxonium fluoborate (CH 3 Hg):i0BF 4 are described. A method for the preparation of methylmerctll'y oxide (CHsHg)20 •by dehydration of methylmercury hydroxide is given. The crystals of tris-methylmercury-oxonium :fluobor!lte have a trigonal symmetry, the hexagonal cell being a = 23.85 A, c = 10.72 A, z = 18. The Patterson synthesis along the c-axis was computed .
The 5G New Radio (NR) technology operating in millimeter wave (mmWave) frequency band is designed... more The 5G New Radio (NR) technology operating in millimeter wave (mmWave) frequency band is designed for support bandwidth-greedy applications requiring extraordinary rates at the access interface. However, the use of directional antenna radiation patterns, as well as extremely large path losses and blockage phenomenon, requires efficient algorithms to support these services. In this study, we consider the multi-layer virtual reality (VR) service that utilizes multicast capabilities for baseline layer and unicast transmissions for delivering an enhanced experience. By utilizing the tools of stochastic geometry and queuing theory we develop a simple algorithm allowing to estimate the deployment density of mmWave NR base stations (BS) supporting prescribed delivery guarantees. Our numerical results show that the highest gains of utilizing multicast service for distributing base layer is observed for high UE densities. Despite of its simplicity, the proposed multicast group formation sche...
Nowadays, mobile operators are faced with a problem of shortage of radio resources required for q... more Nowadays, mobile operators are faced with a problem of shortage of radio resources required for qualitative customer services. One of the possible solutions is the framework named LSA (Licensed Shared Access), which is developed with the assistance of ETSI. The LSA spectrum is shared between the owner (incumbent) and LSA licensee (e.g., mobile network operator). At any time, LSA spectrum could be used by incumbent or mobile network operator but not together at once. In this connection, if the incumbent needs its frequency, then LSA band becomes unavailable for mobile operator. This leads to service interruptions for mobile operator users. In this paper, we describe two possible Radio Admission Control (RAC) scheme models of the 3GPP LTE cellular network within LSA framework as finite queuing systems with reliable (single-tenant band) and unreliable (multi-tenant band) servers. Multi-tenant band is assumed to be intolerant to traffic delay. The formulas for calculating the performanc...
2015 7th International Congress on Ultra Modern Telecommunications and Control Systems and Workshops (ICUMT), 2015
As it is predicted that mobile traffic demand will reach an astonishing 190 exabytes by 2018, cur... more As it is predicted that mobile traffic demand will reach an astonishing 190 exabytes by 2018, current methods of spectrum allocation and management need to be rethought towards more advanced sharing of frequency bands. To this end, a novel regulatory framework has recently emerged, named Licensed Shared Access (LSA), which enables guaranteed spectrum access for a limited number of sharers. However, realistic LSA band operation may result in its abrupt unavailability, causing traffic delays and even network access failures in case of unsuccessful “evacuation” of a user back to conventional cellular bands. In this paper, we formulate an adequate queuing-theoretical model for evaluating such service failure and interruption probability for users that attempt to operate within a cell of a network with the LSA capability.
IEEE Transactions on Wireless Communications
Terahertz (THz) communications systems are expected to become a major enabling technology at the ... more Terahertz (THz) communications systems are expected to become a major enabling technology at the air interface in sixth generation (6G) cellular systems. However, utilizing extremely narrow antenna radiation patterns at both base station (BS) and user equipment (UE) sides, these systems are affected by not only dynamic blockage but micromobility of UEs. To alleviate the impact of both factors one may utilize the multiconnectivity mechanism allowing for UE to remain connected to several BSs simultaneously and switch between them in case the active connection is lost. In this work, we develop a mathematical framework to characterize the outage probability and spectral efficiency associated with different degrees of multiconnectivity in dynamic blockage and micromobility environment for different beamsearching design options. Our results demonstrate that the presence of UE micromobility may have a positive impact on system performance. Particularly, multiconnectivity allows improving outage and spectral efficiency for small and medium blockers density (up to 0.5 bl./m 2) up to that of an ideal system with zero beamsearching times. Furthermore, higher gains are observed for higher degrees of multiconnectivity (e.g., greater than two) as compared to the system with only blockage impairments. For higher blockers densities, however, the reverse effect is observed.
2019 IEEE 30th Annual International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC), 2019
Multicasting is widely used in conventional wired and wireless networks as it allows to significa... more Multicasting is widely used in conventional wired and wireless networks as it allows to significantly improve resource utilization in presence of users interested in the same content. However, the support of this type of service in prospective 5G New Radio (NR) systems has received only little attention so far. In this paper, merging the tools of queuing theory and stochastic geometry we develop a model of 5G NR base station (BS) serving a mixture of unicast and multicast traffic. We validate our model against computer simulations using multicast/unicast session drop probabilities and system resource utilization as metrics of interest. Our numerical results illustrate that the presence of multicast type of traffic severely compromises performance of unicast sessions. Furthermore, this effect is amplified when the inter-site distance (ISD) between BSs increases. Thus, in order to satisfy prescribed performance guarantees in terms of unicast and multicast session drop probabilities, explicit resource reservation mechanism at NR BS might be required.
2014 6th International Congress on Ultra Modern Telecommunications and Control Systems and Workshops (ICUMT), 2014
Presently, we observe an unprecedented growth of traffic volumes in modern cellular networks. Con... more Presently, we observe an unprecedented growth of traffic volumes in modern cellular networks. Consequently, to effectively meet the impeding capacity crunch, current spectrum bands can be extended by using LSA (Licensed Shared Access) - the promising technology that allows an operator to lease additional frequency bands in order to satisfy the increasing data rate requirements. This technology is naturally suitable for the state-of-the-art 3GPP LTE cellular networks, since it allows to flexibly control resource allocation across the network users. Owing to that, the operator can employ the LSA band whenever desired to improve area capacity and increase data rate. However, due to the fact that the LSA band may be unexpectedly revoked by its original owner, there exists a certain chance of degradation in system performance and user service quality. This paper focuses on studying a one-cell 3GPP LTE system over the LSA technology, with both analysis and simulations, by proposing a base...
Prospective 5G New Radio (NR) systems offer unprecedented capacity boost by the ultradense deploy... more Prospective 5G New Radio (NR) systems offer unprecedented capacity boost by the ultradense deployments of small cells operating at mmWave frequencies, with massive available bandwidths. They will facilitate the provisioning of exceptionally demanding mission-critical and resource-hungry applications that are envisaged to utilize the 5G communications infrastructure. In this work, we provide an analytical framework for 5G NR system analysis in terms of queuing theory. We consider a multiservice queuing system with a limited resource with customers that demand varying amount of resource within their service time. Such an approach provides more accurate performance evaluation compared to conventional multiservice models. For the considered model, we propose a method that allows to calculate the stationary probability distribution to the specified accuracy. Our findings are illustrated with a numerical example.
Lecture Notes in Computer Science, 2015
As the demand for higher bit rates in LTE networks increases, new technologies to enhance the eff... more As the demand for higher bit rates in LTE networks increases, new technologies to enhance the effectiveness of radio resource utilization are introduced. One of them is Multimedia Broadcast Multicast Service (MBMS) that enables the usage of multicast technology for multiple resource demanding services, e.g. file repair procedure, intended for resending lost or damaged file segments to users. An important question is to find the periodicity of resending file segment, i.e. forthcoming interval for collecting user requests for repair the same file segment. To address this problem, we propose a Markov model of file repair procedure and formulas for calculating the performance measures – blocking probability, mean delay of file repair to start, and radio channel downtime probability. We also formulate and numerically solve a non-linear optimization problem for mean value of the mentioned polling interval.
Proceedings of the Selected Papers of the 12th International Workshop on Applied Problems in Theory of Probabilities and Mathematical Statistics (Summer Session) , 2018
The expected growth in the mobile video (including streaming video, video downloading, conferenci... more The expected growth in the mobile video (including streaming video, video downloading, conferencing, etc.) now is the key driver for rapid development of 5G wireless network technologies. This paradigm forces wireless networks to manage their resources as effectively as possible. One of the most appropriate solutions for video traffic that may provide the sufficient spectral efficiency is multicasting. Multicast sessions allows a group of users to simultaneously access the same multimedia content with the same QoE parameters. In this paper we consider different methods of multicast subgrouping. An analytical framework in the from of a queuing network is proposed to study the network performance, and a comparative study of network performance metrics under different user movement scenarios is presented.
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Papers by Darya Ostrikova