Caching-Aided Collaborative D2D Operation for Predictive Data Dissemination in Industrial IoT

Industrial automation deployments constitute challenging environments where moving IoT machines may produce high-definition video and other heavy sensor data during surveying and inspection operations. Transporting massive contents to the edge network infrastructure and then eventually to the remote human operator requires reliable and high-rate radio links supported by intelligent data caching and delivery mechanisms. In this work, we address the challenges of contents dissemination in characteristic factory automation scenarios by proposing to engage moving industrial machines as device-to-device (D2D) caching helpers. With the goal to improve reliability of high-rate millimeter-wave (mmWave) data connections, we introduce the alternative contents dissemination modes and then construct a novel mobility-aware methodology that helps develop predictive mode selection strategies based on the anticipated radio link conditions. We also conduct a thorough system-level evaluation of representative data dissemination strategies to confirm the benefits of predictive solutions that employ D2D-enabled collaborative caching at the wireless edge to lower contents delivery latency and improve data acquisition reliability

On the Temporal Effects of Mobile Blockers in Urban Millimeter-Wave Cellular Scenarios

Millimeter-wave (mmWave) propagation is known to be severely affected by the blockage of the line-of-sight (LoS) path. In contrast to microwave systems, at shorter mmWave wavelengths such blockage can be caused by human bodies, where their mobility within environment makes wireless channel alternate between the blocked and non-blocked LoS states. Following the recent 3GPP requirements on modeling the dynamic blockage as well as the temporal consistency of the channel at mmWave frequencies, in this paper a new model for predicting the state of a user in the presence of mobile blockers for representative 3GPP scenarios is developed: urban micro cell (UMi) street canyon and park/stadium/square. It is demonstrated that the blockage effects produce an alternating renewal process with exponentially distributed non-blocked intervals, and blocked durations that follow the general distribution. The following metrics are derived (i) the mean and the fraction of time spent in blocked/non-blocked state, (ii) the residual blocked/non-blocked time, and (iii) the time-dependent conditional probability of having blockage/no blockage at time t1 given that there was blockage/no blockage at time t0. The latter is a function of the arrival rate (intensity), width, and height of moving blockers, distance to the mmWave access point (AP), as well as the heights of the AP and the user device. The proposed model can be used for system-level characterization of mmWave cellular communication systems. For example, the optimal height and the maximum coverage radius of the mmWave APs are derived, while satisfying the required mean data rate constraint. The system-level simulations corroborate that the use of the proposed method considerably reduces the modeling complexity.Comment: Accepted, IEEE Transactions on Vehicular Technolog

Objective Function Development Based on the Parameters of a Regional Terminal Network

The article is devoted to the development of the objective function for calculating the parameters of a terminal network in a region. The key parameters of a terminal network, as logistic system, are described. The factors influencing the parameters of a terminal network are analyzed, and the objective function, concerning the value and qualitative aspects for determining the transport and spatial/quantitative parameters proposed. The level of service quality for the clients is also taken into account. The heuristic solution method, and the results of the approach are demonstrated with the help of an application example concerning different combinations of distribution.Der Artikel widmet sich der Modellierung eines Transportnetzes, das, unter Beachtung der Lage der Distributionszentren und der Lage der Kunden, minimale Gesamtlogistikkosten ergibt. Diese setzen sich wiederum aus den Transport- und aus den Standortkosten hinsichtlich der Lager- und Betriebskosten der Distributionszentren zusammen. Darüber hinaus wird auch die Maximierung beziehungsweise das Niveau der Servicequalität für die Kunden einbezogen. Das heuristische Lösungsverfahren wird anschließend an einem Anwendungsbeispiel hinsichtlich unterschiedlicher Kombinationen von Distributionszentren erprobt und hinsichtlich der Zielerreichung dokumentiert

Системы M|G|1 с групповым обслуживанием и их применение к анализу модели протокола управления потоковой передачей. Часть II

In this paper we introduce an analytical model of the stream control transmission protocol - a queuing system with batch service and job bundling timeout. The applicability of the analytical models in which jobs are served in batches of fixed and variable size [1] is assessed based on numerical results. An algorithm for the calculation of key performance measures is obtained. We also consider the process of signaling messages transmission over IP-network and analyze protocol parameters to provide quality of service in mobile networks.В статье изложены результаты разработки модели функционирования протокола управления потоковой передачей (Stream Control Transmission Protocol, SCTP) в виде системы с групповым обслуживанием заявок. Исследована степень адекватности классических моделей типа ||1 с обслуживанием группами переменной и фиксированной длины [1] применительно к анализу показателей качества обслуживания протокола SCTP. Проведён численный анализ параметров качества функционирования протокола для случая передачи сигнального трафика сети сотовой подвижной связи

Модель выделения ресурсов беспроводной сети объёмами случайной величины

The objective of this paper is the construction and analysis of the model of the wireless LTE network (Long Term Evolution) as a multiserver queuing system where losses are caused by a lack of resources required to service requests. Adopted by the service application takes a random amount of resources given to several types of distribution functions. Random vectors describing the requirements of applications to resources, processes do not depend on input flow and service distribution are jointly independent and identically distributed. L independent Poisson flows of requests enter the system, and there are N identical devices. Service times are distributed exponentially. The functioning of the system is described by the semi-Markov process, which takes into account the number of serviced requests, their types and amounts of resources they occupy. Explicit expressions for the stationary distribution of the semi-Markov process, and the theorem on product form solution are main results of the paper. Further studies suggest checking the hypothesis of invariance with respect to the form of the stationary distribution of the distribution of the service time and the development of numerical methods for the analysis of probability measures of the system.Задачей данной статьи является построение и анализ модели соты беспроводной сети LTE (Long Term Evolution) в виде многолинейной системы массового обслуживания (СМО) с потерями, вызванными нехваткой ресурсов, необходимых для обслуживания заявок. Принятая на обслуживание заявка занимает случайный объем ресурсов нескольких типов с заданными функциями распределения. Случайные векторы, описывающие требования заявок к ресурсам, не зависят от процессов поступления и обслуживания заявок, независимы в совокупности и одинаково распределены. На систему поступает L независимых пуассоновских потоков заявок, а для их обслуживания имеется N идентичных приборов. Длительности обслуживания заявок распределены по экспоненциальному закону. Функционирование СМО описывается полумарковским процессом, который учитывает число находящихся на обслуживании заявок, их типы и объёмы занимаемых ими ресурсов. Получены явные выражения для стационарного распределения полумарковского процесса, а основным результатом статьи является теорема о мультипликативности по числу входящих потоков стационарного распределения объёмов занятых ресурсов. Дальнейшие исследования предполагают проверку гипотезы об инвариантности вида стационарного распределения относительно закона распределения длительности обслуживания, а также разработку численных методов для анализа вероятностно-временных характеристик системы

Построение и анализ модели входного коммутатора в сети с оптической коммутацией

Currently, there are two generally recognized principles of switching of information signals in high-speed networks: networks with wave routing, and networks with the principle of optical packet switching. In networks with wave routing it is not required to produce opto-electrical and electro-optical conversions and to create a buffer, but with this switching principle the working range of wavelengths is not efficiently used. In networks with optical packet switching the traffic is transmitted in packets, which consist of a header and an information part of a consistent size. In this case, using of the frequency range is the most complete, but there is a need of optical-electronic conversions. In an effort to combine the advantages of two optical switching technologies, a new combined switching principle was proposed, called optical switching bursts. In this technology there are not buffering and electronic processing in intermediate nodes, there is a reservation of the channel for a limited time. For the effective implementation of such a network connection, we must calculate its probability characteristics. To assess probabilistic characteristics of the network the methods of theory of mass service are widely used. The input switch is one of the key devices on the network. The article describes the input switch of the network with the optical switching of bursts, calculates the probable characteristics of the network using analytical and simulation models. Examples of the calculation of the probability of blocking of packets flowing in the input switch are presented.В настоящее время существует два общепризнанных принципа коммутации информационных сигналов в высокоскоростных сетях: сети с волновой маршрутизацией и сети с принципом оптической коммутацией пакетов. В сетях с волновой маршрутизацией не требуется производить оптико-электрических и электро-оптических преобразований и создавать буфер, но при данном принципе коммутации неэффективно используется рабочий диапазон длин волн. В сетях с оптической коммутацией пакетов трафик передаётся в виде пакетов, которые состоят из заголовка и информационной части постоянного размера. В данном случае частотный диапазон используется наиболее полно, но появляется необходимость оптико-электронных преобразований. Стремясь соединить преимущества двух технологий оптической коммутации, был предложен новый комбинированный принцип коммутации, получивший название оптической коммутации пачек. В данной технологии нет буферизации и электронной обработки данных в промежуточных узлах, присутствует резервирование канала на ограниченное время. Для эффективного внедрения такой сети связи необходимо рассчитать её вероятностные характеристики. Для оценки вероятностных характеристик сети широко используются методы теории массового обслуживания. Входной коммутатор является одним из ключевых устройств сети. В статье описывается работа входного коммутатора сети с оптической коммутацией пачек, производится расчёт вероятных характеристик сети с использованием аналитической и имитационных моделей. Приведены примеры расчёта вероятности блокировки пакетов, поступающих во входной коммутатор

Evaluation of the New and Accepted Customers Blocking Probabilties in a Network of Resource Loss Systems

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 they receive service for an exponentially distributed time. Once the service is completed, they return back to the original node and continue its service. Customers require a random volume of limited resources. If there are not enough of unoccupied resources upon the arrival of a customer, then it is considered lost. Similarly, if an accepted customer is rerouted to another node and finds that there are not enough of resources to meet its requirements, then it is also lost. In this paper, we provide an approach to analyze the stationary behavior of the considered system, as well as establish expressions for the new customer loss probability and the accepted customer loss probability. The developed model has a wide range of applications in performance evaluation of fifth generation (5G) New Radio (NR) access networks. To this aim, we investigate the response of the considered service system in detail by revealing critical dependencies and trade-offs between input system parameters and performance measures of interest.acceptedVersionPeer reviewe