Complex Telecommunication Networks Research Articles

Predicting Network Hardware Faults through Layered Treatment of Alarms Logs.

Maintaining and managing ever more complex telecommunication networks is an increasingly difficult task, which often challenges the capabilities of human experts. There is a consensus both in academia and in the industry on the need to enhance human capabilities with sophisticated algorithmic tools for decision-making, with the aim of transitioning towards more autonomous, self-optimizing networks. We aimed to contribute to this larger project. We tackled the problem of detecting and predicting the occurrence of faults in hardware components in a radio access network, leveraging the alarm logs produced by the network elements. We defined an end-to-end method for data collection, preparation, labelling, and fault prediction. We proposed a layered approach to fault prediction: we first detected the base station that is going to be faulty and at a second stage, and using a different algorithm, we detected the component of the base station that is going to be faulty. We designed a range of algorithmic solutions and tested them on real data collected from a major telecommunication operator. We concluded that we are able to predict the failure of a network component with satisfying precision and recall.

Analysis of the probability of connectivity of a telecommunications network based on the reduction of several non-connectivity events to a union of independent events

Introduction: For large and structurally complex telecommunication networks, calculating the connectivity probability turns out to be a very cumbersome and time-consuming process due to the huge number of elements in the resulting expression. The most expedient way out of this situation is a method based on the representation of a network connectivity event in the form of sums of products of incompatible events. However, this method also requires performing additional operations on sets in some cases. Purpose: To eliminate the main disadvantages of the method using multi-variable inversion. Results: It is shown that the connectivity event of a graph should be interpreted as a union of connectivity events of all its subgraphs, which leads to the validity of the expression for the connectivity event of the network in the form of a union of connectivity events of typical subgraphs (path, backbone, and in general, a multi-pole tree) of the original random graph. An iterative procedure is proposed for bringing a given number of connectivity events to the union of independent events by sequentially adding subgraph disjoint events. The possibility of eliminating repetitive routine procedures inherent in methods using multi-variable inversion is proved by considering not the union of connectivity events (incoherence) degenerating into the sum of incompatible products, but the intersection of opposite events, which also leads to a similar sum. However, to obtain this sum, there is no need to perform a multi-variable inversion for each of the terms over all those previously analyzed. Practical relevance: The obtained analytical relations can be applied in the analysis of reliability, survivability or stability of complex telecommunications networks.

Large Closed Queueing Networks in Semi-Markov Environment and Their Application

The paper studies closed queueing networks containing a server station and k client stations. The server station is an infinite server queueing system, and client stations are single-server queueing systems with autonomous service, i.e. every client station serves customers (units) only at random instants generated by a strictly stationary and ergodic sequence of random variables. The total number of units in the network is N. The expected times between departures in client stations are (Nμj)−1. After a service completion in the server station, a unit is transmitted to the jth client station with probability pj (j=1,2,…,k), and being processed in the jth client station, the unit returns to the server station. The network is assumed to be in a semi-Markov environment. A semi-Markov environment is defined by a finite or countable infinite Markov chain and by sequences of independent and identically distributed random variables. Then the routing probabilities pj (j=1,2,…,k) and transmission rates (which are expressed via parameters of the network) depend on a Markov state of the environment. The paper studies the queue-length processes in client stations of this network and is aimed to the analysis of performance measures associated with this network. The questions risen in this paper have immediate relation to quality control of complex telecommunication networks, and the obtained results are expected to lead to the solutions to many practical problems of this area of research.

Technical Systems with Structural and Time Redundancy: A Probabilistic Analysis of Their Performance

A generalized interpretation is given to the reliability concepts so that the influence of different random actions (perturbations) on the structure of technical systems can be taken into account within a unified methodological approach. Typical subsystems of complex telecommunication networks, such as computing systems, two-pole data transfer networks and others, are investigated. An important probabilistic-time characteristic of the performance of technical systems with structural and time redundancy is derived in terms of Laplace transform.

Self-organizing networks

With the advent of inexpensive, distributed, powerful computers has come the need for network telecommunications that can transfer data between machines and between users and machines. Fortunately, during the past two decades, major advances have been achieved in telecommunications, ranging from basic improvements in hardware and software design to the creation of such fundamental architectural concepts as the Open System Interconnect (OSI) model developed by the International Standards Organization (ISO). However, although significant progress has been made, one area in telecommunications still requires further development. Until now, we have generally designed protocols for complex telecommunication networks, founded on the assumption that these networkds are static. This assumption facilitates the design of routing algorithms, algorithms for network management, and network topology control. This assumption, however, imposes constraints on the end-user of such networks. Specifically, a user with a high-performance workstation should be able to easily move his/her machine from network to network. However, this movement cannot occur in most networks without first notifying system administrators, in order that appropriate changes in host tables are established and distributed—a process that can take days or weeks to complete. Similarly, many networks today are constrained as to how they can modify their operating parameters (topology, channeltransmission rates, data-flow rates, and alternate routing) to provide service under adverse conditions, such as network-node failures. Note, though, that these constraints are not fundamental to network designs. They have come about primarily because it has been easier to implement ‘first-generation’ networks under these ‘static’ assumptions. However, current telecommunications technology has matured to the point where we can now strive toward developing ‘second-generation’ networks, which we shall call in this paper ‘self-organizing networks’. Our approach to discussing these networks will be to begin with a description of an open system architecture and an example of a network that meets most of the attributes of self-organization. Using these introductory examples, presented in Section 2, we will proceed to discuss the generic issue, ‘binding’, fundamental to self-organizing network designs. We show that if a network is to be self organizing, dynamic binding must be supported. We will then describe research we are pursuing in developing architectures, algorithms, and protocols that permit networks to self-organize. The results of this research will be networks that permit flexible access and that are inherently robust.

Reliability analysis of telecommunication networks using cutset approach

The reliability of complex telecommunication networks is analysed in this paper. Failure is defined as the reduction below a required limit of the number of available channels between two given points. This definition is more flexible and pragmatic than the usual disconnection definition. A general model is presented for estimating the network reliability in terms of its topology and branch capacity probability functions. Expressions for branch probability functions are developed for full availability, blocking systems. The analysis is supplemented by a numerical example.