Eduard Sopin

Peoples' Friendship University of Russia (RUDN University) · Applied probability and informatics department

The modern 5G millimeter wave (mmWave) New Radio (NR) systems as well as future terahertz (THz) radio access technologies (RAT) will heavily rely on beamforming to combat the excessive path losses. Additionally, both RATs target similar bandwidth-greedy non-elastic traffic and are affected by the blockage phenomena. To improve service reliability i...

Rate adaptation is advantageous property allowing applications to match the rate offered by the network. These applications running over the millimeter wave (mmWave) 5G or future sub-terahertz (sub-THz) 6G systems, may experience unwarranted rate degradation as a result of outage events caused by blockages. In this paper, we study the impact of rat...

Terahertz (THz) wireless access is considered as a next step towards sixth generation (6 G) cellular systems. By utilizing even higher frequency bands than 5 G millimeter wave (mmWave) New Radio (NR), they will operate over extreme bandwidth delivering unprecedented rates at the access interface. However, by relying upon pencil-wide beams, these sy...

5G New Radio (NR) technology operating in millimeter wave (mmWave) band is expected to be utilized in areas with high and fluctuating traffic demands such as city squares, shopping malls, etc. The latter may result in quality of service (QoS) violations. To deal with this challenge, 3GPP has recently proposed NR unlicensed (NR-U) technology that ma...

Terahertz (THz) wireless access is considered as a next step towards sixth generation (6G) cellular systems. By utilizing even higher frequency bands than 5G millimeter wave (mmWave) New Radio (NR), they will operate over extreme bandwidth delivering unprecedented rates at the access interface. However, by relying upon pencil-wide beams, these syst...

Millimeter wave (mmWave) and terahertz (THz)radio access technologies (RAT) are expected to become a critical part of the future cellular ecosystem providing an abundant amount of bandwidth in areas with high traffic demands. However, extremely directional antenna radiation patterns that need to be utilized at both transmit and receive sides of a l...

The paper considers a network of resource loss systems (ReLS) with random resource requirements and two types of nodes. Customers initially arrive to the first type of nodes, where they receive service for exponentially distributed time. The service of customers can be interrupted. In this case, they are rerouted to the second type of nodes, where...

Today, the research community and standardization bodies seek for a systematic answer to address the effects of temporal variability in mobile traffic. One of a viable option for mitigating the impact of traffic fluctuations is offloading in unlicensed bands. In this paper, we have described model of offloading customers on unlicensed frequency ran...

5G New Radio (NR) technology operating in millimeter wave (mmWave) band is expected to be utilized in areas with high and fluctuating traffic demands such as city squares, shopping malls, etc. The latter may result in quality of service (QoS) violations. To deal with this challenge, 3GPP has recently proposed NR unlicensed (NR-U) technology that ma...

Modern wireless networks are characterized by high user mobility. This factor can lead to changes in the quality of the channel during the lifetime of the interaction session. To take into account the fact of user movement in a resource queuing system with signals are introduced. Signal arrivals trigger resource reallocation of customers in the sys...

The offloading of computing tasks to the fog computing system is a promising approach to reduce the response time of resource-greedy real-time mobile applications. Besides the decreasing of the response time, the offloading mechanisms may reduce the energy consumption of mobile devices. In the paper, we focused on the analysis of the energy consump...

In wireless networks, the bitrate received by a user session depends not only on the fraction of allocated resources of the base station but also on the number of factors affecting the signal-to-noise ratio. These factors include a distance between a mobile device and the base station, walls, buildings between them, etc. As a result, the bitrate of...

The emerging 5G New Radio (NR) cellular systems that may operate in millimeter-wave (mmWave) frequency bands are expected to offer larger bandwidths. They are to be deployed in densely crowded environments, where the traffic load has a high degree of variability, which may introduce capacity bottlenecks. One of the options to alleviate the latter i...

Millimeter wave (mmWave) and terahertz (THz) radio access technologies (RAT) are expected to become a critical part of the future cellular ecosystem providing an abundant amount of bandwidth in areas with high traffic demands. However, extremely directional antenna radiation patterns that need to be utilized at both transmit and receive sides of a...

Fifth generation millimeter wave New Radio (NR) base stations (BS) are expected to be deployed in areas with extremely high and drastically fluctuating traffic demands resulting in frequent QoS (Quality of Service) violations in terms of provided rate at the access interface, especially, during busy hour conditions. As one of the measures to combat...

To alleviate the impact of outages caused by dynamic blockage of propagation paths in millimeter wave (mmWave) systems, 3GPP has proposed multi-connectivity operation, where user equipment (UE) maintains simultaneous links to both sub-6 GHz and mmWave BSs. We address one of the most challenging prospective deployments – multi-lane street deployment...

In this paper, we develop the queuing system model with processor sharing discipline with random serving rate coefficients. Each arriving customer is characterized by its length (job volume) and a serving rate coefficient determined by some probability distributions. The coefficients remain constant during the service process of customers. The prop...

In modern infrastructure, the mobile network operator, the owner of the equipment, leases part of the resources of the base stations. Network slicing allows several virtual network operators to use the resources of one base station. This allows operators and resource owners to provide and manage multiple dedicated logical networks with specific fun...

The intermittent nature of millimeter wave (mmWave) links caused by human-body blockage is an intrinsic property of the 5G New Radio (NR) technology that may cause drops of sessions already accepted for service. To improve the session continuity, multiconnectivity and guard capacity mechanisms have been proposed recently. Multiconnectivity enables...

Blockage of millimeter-wave (mmWave) radio propagation paths in dense mobile scenarios requires advanced techniques to preserve session continuity in 5G New Radio (NR) systems. In this work, we employ the tools of stochastic geometry and queuing theory as well as rely on 3GPP cluster-based propagation modeling to formulate a mathematical framework,...

Fog computing brings computing infrastructure to the edge of the network. This enables resource-greedy real-time mobile applications by offloading them to the fog, which provides enough computing resources and reduces the response time in comparison with cloud computing-based solutions. In the paper, we analyze the two-parameter offloading mechanis...

5G millimeter wave (mmWave) New Radio (NR) base stations (BS) are expected to be deployed in areas with extremely high and drastically fluctuating traffic demands resulting in frequent quality-of-service violations in terms of the provided rate at the access interface, especially, during busy hour conditions. As a cost-efficient countermeasure we c...

This book constitutes the refereed proceedings of the 25th International Conference on Analytical and Stochastic Modelling Techniques and Applications, ASMTA 2019, held in Moscow, Russia, in October 2019. Methods of analytical and stochastic modelling are widely used in engineering to assess and design various complex systems, like computer and com...

One of the ways to enable smooth coexistence of ultra reliable low latency communication (URRLC) and enhances mobile broadband (eMBB) services at the air interface of perspective 5G New Radio (NR) technology is to utilize preemptive priority service. In this paper, we provide approximate analysis of the queuing system with random resource requireme...

Cloud-based Radio Access Network (C-RAN) is a centralized cloud computing architecture for radio access networks (RANs) that provides large-scale deployment, joint support for radio technologies, and real-time virtualization capabilities. By moving signal processing functions to a data center, C-RAN significantly reduces power consumption and deplo...

Fog computing provides an efficient solution for mobile computing offloading, keeping tight constraints on the response time for real-time applications. The paper takes into account the variation of tasks by introducing the joint distribution function of the required processing volume and data size to be transmitted. We propose an offloading criter...

Virtual radio resource management system (VRRM) provides optimal sharing of virtualized resources of an infrastructure provider (InP) between several virtual network operators (VNO). One of the main objectives of the VRRM is to optimize the usage of radio access network (RAN) by dynamic sharing between slices in a fair manner according to their con...

Dynamic blockage of millimeter-wave (mmWave) radio propagation paths by dense moving crowds calls for advanced techniques to preserve session continuity in the emerging New Radio (NR) systems. To further improve user performance by balancing the new and ongoing session drop probabilities, we investigate the concept of guard capacity – reserving a f...

Introduction: In 3GPP New Radio (NR) systems, frequent radio propagation path blockages can lead to the disconnection of ongoingsessions already accepted into the system, reducing the quality of service in the network. Controlling access to system resource byprioritizing for the ongoing sessions can increase the session continuity. In this paper, w...

Nowadays, the number of mobile subscribers has increased significantly. It is predicted that the number of subscribers will reach 9.5 billion by 2020. With such rapid growth, telecommunications networks suffer from several problems, such as lack of bandwidth, the occurrence of collisions and interference. To cope with the problems, it was proposed...

The 3GPP standardization rapidly moves forward with studies of a wider bandwidth waveform as well as adaptation of the emerging 5G New Radio (NR) based access to the unlicensed spectrum (NR-U). One of the basic architectures for NR-U involves carrier aggregation of an anchor – licensed – NR carrier and a secondary carrier in unlicensed spectrum, wh...

In the paper, a wireless network is modelled in terms of multiserver queuing system with limited resources, random resource requirements and signals that trigger resource reallocation procedure. For the queuing system, we derive the set of balance equations and propose the solution method. Moreover, the formulas for main performance measures are ob...

Fog computing is a good solution for response time-critical applications, which need a lot of processing time. Fog allows mobile devices to offload some tasks and, consequently, to increase battery life-time. By the way, unlike classical cloud solutions, fog computing provides very low latency thanks to its distributed computing infrastructure. In...

We constructed mathematical models of cloud computing systems taking into account various mechanisms for increasing energy efficiency in terms of queuing theory, and analytical expressions for the main characteristics of energy consumption and server performance metrics were obtained. We investigated and compered three different energy efficiency i...

The authors consider further generalization of the queuing systems, in which customers require not only a server but also a certain amount of limited resources. In the considered queuing system, arrival and serving intensities depend on the statе of the system. The authors assume an arbitrary distribution of the service time. The authors prove that...

We consider a cloud computing system with three different mechanisms for increasing the energy efficiency of cloud computing systems. We investigate how energy efficiency of a cloud system is affected by a waiting time before a server goes to switch on/standby mode and threshold-based switch. We developed four mathematical models of Cloud computing...

In this work, a simplification approach for analysis of queueing systems with random requirements is proposed. The main point of the approach is to keep track of only total amount of occupied system resources. Therefore, we cannot know the exact amount of resources released by the departure of a customer, so we assume it a random variable with cond...

We analyze a multiserver queuing system, in which customers require a server and a certain amount of limited resources for the duration of their service. For the case of discrete resources, we develop a recurrence algorithm to evaluate the model’s stationary probability distribution and its various stationary characteristics, such as the blocking p...

One of the key performance measures of cloud computing systems is the response time. However, the mean value of this characteristic does not give the full picture of quality of service. Therefore, we derive the cumulative distribution function (CDF) of the response time in terms of Laplace-Stieltjes transform and use it to evaluate moments of the r...

Enhancing energy efficiency of cloud computing systems is one of the key challenges for cloud providers. One of the most obvious ways to decrease energy consumption is dynamic control of switched on servers according to the system load. However, this approach leads to additional energy and time loss due to switching on/off of computing resources. R...

In the paper, we analyse a multiserver queuing system with discrete limited resources and random resource requirements under MAP arrivals, which can adequately model resource allocation schemes in the contemporary wireless networks. The equilibrium system of equations is derived in the vector form and is solved numerically. With stationary probabil...

Данная работа является первой в серии из двух статей, посвящённых обзору систем массового обслуживания вида «fork-join» (в западной классификации) или системам с расщеплением запросов. Указанная система является естественной моделью для многих других реальных систем. В статье описаны особенности построения этой модели и родственных ей систем, основ...

Public protection and disaster relief (PPDR) situations are becoming increasingly common due to the rapid urbanization of our society. Among these, harsh weather conditions and harmful human activity create challenges for reliable operation of mobile communication infrastructures, which calls for immediate action. The wireless networks of today may...

The paper considers a queuing system with limited resources, random requirements, and signals. Each customer occupies a server and a random amount of resources for the whole service duration. Besides, a Poisson flow of signals arrives to the queue. Signal arrival triggers the resource reallocation process. The model can describe functioning of a wi...

We analyze a multi-server queueing system with limited resources and signals. A customer requires a random value (RV) of the shared resources. Each customer generates a flow of signals triggering the resource reallocation process that make a customer release the occupied amount of resources and request a new RV of resources instead.

We suggest a convolution algorithm for calculating the normalization constant for stationary probabilities of a multiserver queuing system with random resource requirements. Our algorithm significantly reduces computing time of the stationary probabilities and system characteristics such as blocking probabilities and average number of occupied reso...

The modern development of the telecommunication technologies is closely related with the rapid data traffic growth problem under the conditions of limited frequency resources for mobile networks. One of the possible solutions to this problem is the utilization of the Licensed Shared Access (LSA) framework, which is developed with the assistance of...

Modern dense 4G and 5G networks allow placing a wireless access point in every indoor location to optimize wireless coverage. The paper analyzes the signal-to-interference ratio (SIR) for wireless systems operating in adjacent premises, and takes into account the loss of signal power during penetration of a signal through different environments. As...

The need for efficient resource utilization at the air interfaces in heterogeneous wireless systems has recently led to the concept of downlink and uplink decoupling (DUDe). Several studies have already reported the gains of using DUDe in static traffic conditions. In this paper we investigate performance of DUDe with stochastic session arrivals pa...

Processor sharing (PS) queuing systems and particularly their well-known class of egalitarian processor (EPS) sharing are widely investigated by research community and applied for the analysis of wire and wireless communication systems and networks. The same can be said for queuing systems in random environment, with unreliable servers, interruptio...

Cloud computing paradigm proved itself to be a good approach for efficient high-performance computational infrastructure design. Besides performance, one of the most important measures for cloud service providers is energy efficiency of the system. For better energy efficiency, in light load case additional virtual machines are switched off, and sw...

Processor sharing (PS) queuing systems are widely investigated by research community and applied for the analysis of wire and wireless communication systems and networks. Nevertheless, only few works focus on finite queues with both PS discipline and service interruptions. In the paper, compared with the previous results we analyze a finite capacit...

Growing popularity of cloud services is explained by many advantages of them. The accessibility, flexibility, scalability, ease of management, the relatively low cost of implementation can be listed among the main advantages. The demand for cloud services with the ability to change one cloud service provider to another one without any significant c...

In the paper, M2M traffic characteristics in LTE mobile network are investigated. A specific resource scheduler based on the full power policy is considered. For the considered scheduler, the cumulative distribution function of resource requirements of M2M sessions is derived. Then, we approximate it by gamma distribution, which is used to evaluate...

According to analytics, the global mobile date traffic will grow three times faster than fixed traffic by 2019. The number of user’s mobile devices is supposed to increase from 4.1 billion to 4.9 billion while the number of mobile device connections can reach even 10 billion. Broadband speeds in wireless networks are expected to double from 1.7 Mbp...

Cloud computing is promising technology to manage and improve utilization of computing center resources to deliver various computing and IT services. For the purpose of energy saving there is no need to unnecessarily operate many servers under light loads, and they are switched off. On the other hand, some servers should be switched on in heavy loa...

An important feature of next generation networks is a possibility to provide services with various requirements of quality of service (QoS) to users. In accordance with the 3GPP specifications, two types of services are defined – guaranteed bit rate (GBR) services, i.e. real time gaming, and non-guaranteed bit rate (non-GBR) services, i.e. e-mail,...

In current cellular networks, each user session requires a share of radio resources to be served. Performance analysis of such networks can generally be conducted by employing queuing systems with limited resources. However, with the ongoing network densification, the loading on future networks is expected to vary significantly and unpredictably. T...

Cloud computing became a popular computing technology, that provides efficient resource utilization to deliver IT services. Each user requests cloud computing system for use of resources. If the system is busy, then user needs to wait until current user finishes the job. This may result in waiting time increase and drop of request Thus, cloud compu...

Hysteretic control of arrivals is one of the most easy-to-implement and effective solutions of overload problems occurring in SIP-servers. A mathematical model of an SIP server based on the queueing system M-[X]vertical bar G vertical bar 1 < L, H >vertical bar < H, R > with batch arrivals and two hysteretic loops is being analyzed. This paper prop...