Marco Vari

Performance evaluation of indoor localization techniques based on RF power measurements from active or passive devices

The performance of networks for indoor localization based on RF power measurements from active or passive devices is evaluated in terms of the accuracy, complexity, and costs. In the active device case, the terminal to be located measures the power transmitted by some devices inside its coverage area. To determine the terminal position in the area, power measurements are then compared with the data stored in an RF map of the area. A network architecture for localization based on passive devices is presented. Its operations are based on the measure of the power retransmitted from local devices interrogated by the terminal and on their identities. Performance of the two schemes is compared in terms of the probability of localization error as a function of the number (density) of active or passive devices. Analysis is carried out through simulation in a typical office-like environment whose propagation characteristics have been characterized experimentally. Considerations obtained in this work can be easily adapted to other scenarios. The procedure used for the analysis is general and can be easily extended to other situations.

Performance evaluation of GSM robustness against smart jamming attacks

In this paper, we deal with the problem of GSM vulnerabilities to jamming attacks. We pick over the GSM standard to identify smart jamming strategies that can inhibit communications of GSM users, while preserving the energy of the jammer device. In particular, the identified jamming algorithm is focused on the control channels. We evaluate by system simulations the GSM robustness against the analyzed attacks. Obtained results show that the GSM security can be undermined by hampering the synchronization procedures.

An always available control channel for cooperative sensing in cognitive radio networks

In the Cognitive Radio (CR) framework, the Opportunistic Spectrum Access (OSA) is a promising solution to increase spectral efficiency. However in an OSA network secondary unlicensed cognitive nodes have to agree on which spectral resources they are allowed to use without compromising performance of primary licensed users. This requires a common control channel for sharing spectrum sensing information. Among the ways to realize it, the utilization of Ultra-wideband (UWB) techniques has been proposed in the literature. In this paper we face the problem of dimensioning an “always on” underlay UWB signalling network for sensing information exchange among secondary CR nodes avoiding harmful interference to primary users. To this aim, we analyse the tradeoff between the connectivity degree of a multi-hop underlay signalling network, related to the bit-rate of the control channel, and its coexistence with primary licensed systems.

Indoor localization system for first responders in emergency scenario

Recently, wireless indoor location systems have been successfully used in many applications, such as asset tracking, indoor navigation, and inventory management. Such systems become essential in Public Safety and Disaster Relief (PSDR) scenarios, where a robust and reliable first responder positioning system can significantly increase safety in emergency operations. In this paper, we characterize the performance of a RFID-based indoor localization system. We present various tests aimed at assessing the capability of the ILS to identify first responders in different conditions. Results show that, by means of a correct dimensioning of the ILS, high efficiency can be achieved in localization.

mmWaves RSSI indoor network localization

Indoor positioning gained great interest in recent years. Several performance evaluations are available for consolidated systems, especially for ultra-wideband radios. Given the current success of mmWaves networks, in this paper, we investigate the performance of RSSI localization systems operating at mmWaves. Our reference is the IEEE 802.11ad standard for multi-Gbps WLANs. We tested the performance of RSSI localization in several scenarios differing in the number of access points serving as anchors and the RSSI acquisition. Our results show that RSSI localization is still effective at mmWaves using devices compliant with the IEEE 802.11ad standard in terms of sensitivity and frequency bands. We will show that these radios can achieve an accuracy of around 1 m if a sufficient number of measurement samples is acquired.

On the suitability of public mobile networks for supporting train control/management systems

Telecommunications are strategic for train control system operations. The European ERTMS/ETCS system for high speed trains control utilizes dedicated GSM-R mobile network(s). The costs for deployment and maintenance of GSM-R network are not sustainable for the extension of train control to low/medium traffic lines. This paper investigates on the possibility of replacing dedicated mobile radio infrastructures with the radio network integrating one (or more) existing PLMNs and satellite as backup. A methodology for performance assessment is presented and applied to the study of network availability and operational costs. Availability can be improved by allowing train to intelligently select the public network(s) time by time. Operational costs are dictated by the satellite component which may become essential in rural areas. Looking at the European scenario, a discussion on the extension of the Euroradio protocol to operate over multi-bearer mobile network is also presented.

A Downstream Power Back-Off Procedure for Mixed FTTC and FTTDp Scenarios

VDSL2 achieves high bit rates thanks to far-end crosstalk suppression and proper selection of the access network infrastructure. In this paper, we consider one architectural solution, which adopts the standard VDSL2 profile in a Fiber-To-The-Distribution point (FTTDp). During the transition process, FTTDp has to coexist with Fiber-To-The-Cabinet (FTTC) in a mixed VDSL2 scenario. Downstream Power Back-Off (DPBO) for FTTDp is effective to mitigate interference among FTTC and FTTDp. When FTTC terminals are vectored, DPBO leads to reduction of the maximum bit rate for FTTDp as compared to FTTC. In this paper, we propose a modification of the ITU DPBO procedure for FTTC and FTTDp to achieve the same bit rate. The maximum power assigned to FTTDp users is now proportional to the average received power of the vectored FTTC users at the Distribution Point. We obtain the proportionality coefficient, which depends on the number of active FTTC and FTTDp terminals and it is independent of the sub-carrier frequency.

Performance improvement and network TCO reduction by optimal deployment of caching

The growth of new advanced services over Internet, including HD and 4K unicast video, made possible by the development of fixed and mobile broadband and ultra-broadband access, in turn poses important requirements on the evolution of IP transport networks. Sustainability of the Internet ecosystem in the presence of increasing traffic volumes, changing traffic patterns and more demanding application requirements boost the transformation of network architectures. Quality of Experience (QoE) directly influences the number of accesses to video content and the time spent by users to view videos, thus impacting on Telcos and OTTs business models. In this paper we quantitatively evaluate, in terms of application throughput improvement and cost-effectiveness, the impact of content caching inside Telcos networks. We show that distribution of caches inside the IP network improves QoE and reduces network total cost of ownership (TCO).

Telework: At the crossroads of social demand and technology offer

There are different studies and surveys conducted in the field of telework which prove the fact that teleworkers benefit from “independence” in managing their working time and tasks as well as from reduction in commuting costs which one has to incur in order to travel from home to work.

The future of ultrabroadband communications: A roadmap to NGAN

The paper describes some relevant solutions for Next Generation Access Network (NGAN, or NGN), considering evolution from copper legacy network to optical access network (PON, Passive Optical Network) and analysing pros and cons of several PON solutions (TDM-PON, WDM-PON, TWDM and OFMD-PON) as well as potential convergence/coexistence scenarios.