Modeling of Call Dropping in Well-Established Cellular Networks

The increasing offer of advanced services in cellular networks forces operators to provide stringent QoS guarantees. This objective can be achieved by applying several optimization procedures. One of the most important indexes for QoS monitoring is the drop-call probability that, till now, has not deeply studied in the context of a well-established cellular network. To bridge this gap, starting from an accurate statistical analysis of real data, in this paper an original analytical model of the call dropping phenomenon has been developed. Data analysis confirms that models already available in literature, considering handover failure as the main call dropping cause, give a minor contribution for service optimization in established networks. In fact, many other phenomena become more relevant in influencing the call dropping. The proposed model relates the drop-call probability with traffic parameters. Its effectiveness has been validated by experimental measures. Moreover, results show how each traffic parameter affects system performance

Simu5G – An OMNeT++ library for end-to-end performance evaluation of 5G networks

In this paper we introduce Simu5G, a new OMNeT++-based model library to simulate 5G networks. Si-mu5G allows users to simulate the data plane of 5G New Radio deployments, in an end-to-end perspective and including all protocol layers, making it a valuable tool for researchers and practitioners interested in the performance evaluation of 5G networks and services. We discuss the modelling of the protocol layers, network entities and functions, and validate our abstraction of the physical layer using 3GPP-based sce-narios. Moreover, we show how Simu5G can be used to evaluate Multi-access Edge Computing (MEC) and Cellular Vehicle-to-everything (C-V2X) services offered through a 5G network

Modelling and performance evaluation of wireless and mobile communication systems in heterogeneous environments

It is widely expected that next generation wireless communication systems will be heterogeneous, integrating a wide variety of wireless access networks. Of particular interest recently is the integration of cellular networks (GSM, GPRS, UMTS, EDGE and LTE) and wireless local area networks (WLANs) to provide complementary features in terms of coverage, capacity and mobility support. These different networks will work together using vertical handover techniques and hence understanding how well these mechanisms perform is a significant issue. In this thesis, these networks are modelled to yield performance results such as mean queue lengths and blocking probabilities over a range of different conditions. The results are then analysed using network constraints to yield operational graphs based on handover probabilities to different networks. Firstly, individual networks with horizontal handover are analysed using performability techniques. The thesis moves on to look at vertical handovers between cellular networks using pure performance models. Then the integration of cellular networks and WLAN is considered. While analysing these results it became clear that the common models that were being used were subjected to handover hysteresis resulting from feedback loops in the model. A new analytical model was developed which addressed this issue but was shown to be problematic in developing state probabilities for more complicated scenarios. Guard channels analysis, which is normally used to give priority to handover traffic in mobile networks, was employed as a practical solution to the observed handover hysteresis. Overall, using different analytical techniques as well as simulation, the results of this work form an important part in the design and development of future mobile systems

Mobility Support in User-Centric Networks

In this paper, an overview of challenges and requirements for mobility management in user-centric networks is given, and a new distributed and dynamic per-application mobility management solution is presented. After a brief summary of generic mobility management concepts, existing approaches from the distributed and peer-to-peer mobility management literature are introduced, along with their applicability or shortcomings in the UCN environment. Possible approaches to deal with the decentralized and highly dynamic nature of UCNs are also provided with a discussion and an introduction to potential future work