Ekaterina V. Markova

Modelling and performance analysis of pre-emption based radio admission control scheme for video conferencing over LTE

We perceive emerging developments in information and communication technologies (ICTs) in various areas of our dynamic live. The concept of getting services and applications “any time” and “any place” imposes the corresponding development in cellular networks. The rapid worldwide deployment of 4G LTE networks and increasing demand for new services are the key ICT trends that highlight the need for future improvements in technologies underling LTE. Although 3GPP concentrates all standardization activities in LTE, ITU-T recommendations reflect the main quality of service (QoS) requirements in ICTs. Nevertheless, not all QoS related ITU-T recommendations (i.e. E.800-E.899, G.1000-G.1999, Y.1500-Y.1599, Y.2100-Y.2199 series) correspond to todays variety of products and services provided by cellular networks. This fact raises the need for updates in these recommendations. In this paper, we explore QoS measures specific to LTE services adaptively occupying radio resources. This so-called pre-emption process assumes the service degradation as well as service interruption. We propose a pre-emption based radio admission control (RAC) model for two resource demanding video services - video conferencing and video on demand. We apply teletraffic and queuing theories to get a recursive algorithm for calculating its performance measures, namely, blocking probability, pre-emption probability, and mean bit rate.

Modeling the utilization of a multi-tenant band in 3GPP LTE system with Licensed Shared Access

Fueled by the rapid growth of mobile services, the actual demand for efficient sharing of available but underutilized frequency spectrum puts pressure on the responsible players (ITU, ETSI) to rethink the feasible ways of allocating wireless spectrum. Today, the LSA regulatory framework is considered to be an important enabler for optimized spectrum sharing between the incumbent and the LSA licensee (e.g., mobile network operator). At any point of time, the frequency bands can be utilized by only a single party, and the spectrum owner has priority in its usage at all times. In this paper, we introduce a mathematical and a system model for the multi-tenant band within the 3GPP LTE cellular network. As the main output of this work, the obtained numerical results for one multi-tenant band are produced. Said band is assumed to be intolerant to traffic delay and our results include the blocking probability as well as the mean downlink TX power of the eNodeB.

Queuing Model with Unreliable Servers for Limit Power Policy Within Licensed Shared Access Framework

Shared access to spectrum by several parties seems to become one of the most promising approaches to solve the problem of radio spectrum shortage. The framework proposed by ETSI, licensed shared access (LSA), gives the owner absolute priority in spectrum access, to the detriment of the secondary user, LSA licensee. The latter can access the spectrum only if the owner’s QoS is not violated. If the users of both parties need continuous service without interruptions, the rules of shared access should guarantee the possibility of simultaneous access. Balancing the radio resource occupation between parties could take quite a long time compared to the dynamics of the system due to the coordination process by the national regulation authority (NRA). We examine a scheme of the simultaneous access to spectrum by the owner and the LSA licensee that minimizes the coordination activities via NRA. According to this scheme, when the owner needs the spectrum, the power of the LSA licensee’s eNB/UEs is limited. From the LSA licensee’s perspective, the scheme is described in the form of a queuing system with reliable (single-tenant band) and unreliable (multi-tenant band) servers. We show that the infinitesimal generator of the system has a block tridiagonal form. The results are illustrated numerically by estimating the average bit rate of viral videos, which varies due to aeronautical telemetry corresponding to the owner’s traffic.

Approximating performance measures of radio admission control model for non real-time services with maximum bit rates in LTE

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, data communication. Different types of non-GBR services differ one from other, first, in a data volume defining data transfer time. The data transfer time also depends on subscriber devices, which not necessarily support LTE. This fact superimposes restrictions on the possible maximum bit rate. We analyze a multi-rate model of a LTE network with two types of non-GBR services. The radio admission control scheme assumes restrictions on the maximum bit rate and adaptive bit rate changes. These changes depend on the cell load. We apply teletraffic and queuing theories to get an approximate method for calculating the blocking probability.

Flexible Spectrum Management in a Smart City Within Licensed Shared Access Framework

The new generation of communication technologies, named 5G, brings along a variety of emerging applications and services from both human and machine perspectives. The growing demand for bandwidth in 5G may therefore lead to massive deficiency in wireless spectrum availability despite its under-utilization in urban areas. The Smart City paradigm assumes a multitude of communicating machines at high density, which requires improved spectrum management flexibility. The novel licensed shared access (LSA) framework that has attracted recent industrial and academic attention may become a feasible solution to leverage such underutilized spectrum more efficiently. This paper analyzes the effects of applying LSA in the Smart City context by proposing an appropriate mathematical model. Particularly, we focus on the vehicle-to-everything 5G use case where connected devices attempt to distribute their sensed data including occasional video information. The proposed analytical framework allows to capture the probabilities of rare events during such operation by providing with a high level of precision in the resulting performance estimates.

Formalizing Set of Multiservice Models for Analyzing Pre-emption Mechanisms in Wireless 3GPP Networks

Users of wireless 3GPP LTE networks are provided with a wide range of multimedia services with varying QoS requirements; due to this fact a problem of an effective network resources’ distribution arises and, consequently, a task of the optimal RAC schemes development. According to the international standards, two types of services are defined within LTE networks – GBR services and non-GBR services. The GBR services generate streaming traffic and non-GBR services – elastic traffic the bit rate of which can dynamically change depending on the cell load. Also, the service priorities differ and are organized with the help of different mechanisms, e.g. service interruption mechanism and mechanism of bit rate degradation. The paper proposes a formal unique description of RAC schemes that is used to develop an example set of models realizing three possible pre-emption based scenarios in multiservice wireless networks.

IoT-fog based system structure with SDN enabled

IoT is a new communication paradigm that gains a very high importance in the past few years. Fog computing is a form of edge computing that is developed to provide the computing, storage and management capabilities near to users. Employing Fog computing in IoT networks as an intermediate layer between IoT devices and the remote cloud becomes a demand to make use of the edge computing benefits. In this work, we provide a framework for IoT system structure that employs an edge computing layer of Fog nodes. The system employs SDN network with a centralized controller and distributed OpenFlow switches; these switches are enabled with limited computing and processing capabilities. The network is operated based on a data offloading algorithm, that allocates certain processing and computing tasks to some OpenFlow switches that has unused resources. The proposed work achieves various benefits to the IoT network such as the latency reduction and higher efficiency of resources utilization. We perform an experiment over a developed testbed to validate the proposed system and results show that the proposed system achieves higher efficiency in terms of latency and resource utilization.

Key solutions for light limitations: toward tactile internet system realization

Enabling haptic communication as well as voice and data over the future 5G cellular system become a demand. Tactile Internet is one of the main use cases of the 5G system that will allow the transfer of haptic communications in real time. The end-to-end latency of 1ms remain the main challenge toward the Tactile Internet system realization, not only for the processing and coding delays but mainly for the limitations of light. In this work, we analyze the key solutions to overcome the light limitations and enable the Tactile Internet over any distances with the required latency. Building a virtual model or model mediated for the remote environment at the edge cloud unit near to the end user is the main solution. By means of AI the virtual model can predict the behavior of the remote environment and thus the end user can interact with the virtual environment with a high system experience. We review the exiting work for the model mediated bilateral systems and discuss its availability for the Tactile Internet system. Finally, we suggest a structure for the Tactile Internet system with the deployment of model mediated.

Analysis of Admission Control Schemes Models for Wireless Network Under Licensed Shared Access Framework.

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 performances measures – blocking probability, probability of service interruption and probability of service band changing – are proposed. The numerical analysis is provided for LSA example scenario of aeronautical telemetry.

Analyzing of Licensed Shared Access Scheme Model with Service Bit Rate Degradation in 3GPP Network

The volume of mobile traffic is growing every year. More and more frequency resources are needed to provide users services with a required level of quality of service (QoS). One of the possible solutions to a problem of radio spectrum shortage is the sharing of spectrum between the owners and LSA licensees. Licensed shared access (LSA) framework gives the owner priority in spectrum access, to the detriment of the secondary user, LSA licensee. If the mobile operator users of both need continuous service without interruptions on the rented part of the spectrum, the rules of shared access should guarantee the possibility of simultaneous access. In this paper we simulate a queuing system and consider a scheme model of LSA framework with the limit power policy. We propose formulas for calculation of main characteristics of the model – a blocking probability and a mean bit rate. These characteristics are very important in teletraffic theory. For example, blocking probabilities help to determine the number of required channels.