The first wireless regional area network standard with a cognitive radio (CR) framework for a broadband fixed or mobile access is IEEE 802.22. This standard based at the concept of sensing and utilizing temporary vacant radio channel in the frequency range from 54 MHz to 862 MHz. The IEEE 802.22 WRAN architectures includes decentralized collection of data about power level and time-dependent spectrum availability with help of customer premise equipment (CPE). The CPE sojourn time at the IEEE 802.22 WRAN is a key performance index for a making decision about vertical handover (VHO) from a current wireless access network as 3GPP LTE to the 802.22 WRAN. This paper present the sojourn time procedure from IEEE 802.22 discovery by CPE to a new IP-session establishment on WRAN. A new integrated architecture is offered for a coordinate access network creation on the base of integrated 3GPP access network discovery and selection function (ANDSF) and IEEE 802.22 Spectrum Manager (SM). © 2017 IEEE.

The first wireless regional area network standard with a cognitive radio (CR) framework for a broadband fixed or mobile access is IEEE 802.22. This standard based at the concept of sensing and utilizing temporary vacant radio channel in the frequency range from 54 MHz to 862 MHz. The IEEE 802.22 WRAN architectures includes decentralized collection of data about power level and time-dependent spectrum availability with help of customer premise equipment (CPE). The CPE sojourn time at the IEEE 802.22 WRAN is a key performance index for a making decision about vertical handover (VHO) from a current wireless access network as 3GPP LTE to the 802.22 WRAN. This paper present the sojourn time procedure from IEEE 802.22 discovery by CPE to a new IP-session establishment on WRAN. A new integrated architecture is offered for a coordinate access network creation on the base of integrated 3GPP access network discovery and selection function (ANDSF) and IEEE 802.22 Spectrum Manager (SM). © 2017 IEEE.

The problem of channel quality estimation for devices in a wireless 5G network is formulated. As a performance metrics of interest we choose the signal-to-interference-plus-noise ratio, which depends essentially on the distance between the communicating devices. A model with a plurality of moving devices in a bounded three-dimensional space and a simulation algorithm to determine the distances between the devices for a given motion model are devised.

This paper explores so called "View-Upload Decoupling scheme" which strictly decouples data to what peer uploads and what it personally views. It is based on the split of downloaded user data streams into two types: the stream of the chosen TV channel and the stream (one or more) of the other TV channel, exclusively, to deliver it to other users. We developed a method for calculating one of the key QoS characteristics in P2P streaming network - the probability of universal streaming for each channel and a system-wide universal streaming across all channels. The statistical probability results of universal streaming for the VUD scheme compared to the traditional redistributing ISO scheme are presented.

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 resources. The algorithm aims to avoid calculation of k-fold convolutions and reasonably use memory resources.

Heavy traffic load in current LTE networks calls for effective radio resource allocation methods and tools for performance evaluation. In this work, we provide an analytical framework for LTE resource allocation in terms of queuing theory. We consider a multiservice queuing system with a finite amount of resources of several types, and allow the customers occupy a random amount of resources upon their arrival. Random resource requirements lead to more accurate performance evaluation compared to conventional multiservice models. For the considered model, we prove that the stationary probability distribution has a multiplicative form. Our findings are illustrated with a numerical example. © 2015 IEEE.

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 cost for a user result in a high competition between cloud providers. Due to this reason, it became important to find the optimal performance measures of cloud systems. These measures, on the one hand, must meet all the requirements of Service Level Agreement (SLA), on the other hand, do not lead to excessive costs for provider. The paper presents the evaluation of the main service quality characteristics of cloud systems, including formulas for variance of residence time in the synchronization buffer. For the analysis of a cloud system, fork-join queues with corresponding methods of its approximation were used. © Springer International Publishing AG 2016.

The rapid development of P2P technologies and appearing scope of applications involving it will help to solve a lot of optimization problems and improve the QoS for data delivery services. This paper is an extension of previous papers devoted to modelling P2P media streaming service and describes the design and simulation software architecture of P2P streaming network with buffering mechanism for a single media stream. We consider mathematical model in the form of discrete Markov chain taking into account the so-called lag-the time delay of data transfer between peers, download strategies and possible peer groups according to distances between them. Program algorithm is presented using UML activity diagram and the simulation results are shown. © ECMS Valeri M. Mladenov, Petia Georgieva, Grisha Spasov, Galidiya Petrova (Editors).

The main signaling protocol for IP Multimedia Subsystem is Session Initiation Protocol. A typical procedure for a session establishment involves two types of signaling messages with different priority: Invite message, which initiate a session, and non-Invite messages, which continue session establishment. In the paper for the analysis of two types signaling messages service process the single server asymmetric polling system with two infinite queues and a non-zero switching time is proposed. We estimate the waiting time for the gated and the exhaustive service disciplines using input data applicable to signaling traffic analysis. For the exhaustive discipline the formulas for the second moments of the waiting time were obtained and calculation of the first and the second moments of the waiting time was carried out. © Springer International Publishing Switzerland 2015.