Marco Petracca

Algorithms for dynamic frequency selection for femto-cells of different operators

The self-installation nature of femtocells sharing the same frequency band can lead to harmful femto-to-femto interference levels. The possibility for operators to share its licensed spectrum allows femtocells of one operator to exploit the frequency resources of other operators. In this paper we propose and analyze the performance of two dynamic frequency selection algorithms that permit to the generic femtocell the smart selection of its operating band, among those available from every operator, starting from the measurements of local interference. The performance of the proposed techniques are analyzed by simulation in terms of outage probability and the achievable Signal-to-Interference Ratio (SIR). It is observed that, in a multi-operator scenario this approach offers significant improvement in terms of achievable network capacity and quality of service to customers.

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.

Integration of Broadband Wireless Technologies and PMR Systems for Professional Communications

The paper contributes to the evolution of Public Safety and Disaster Relief (PSDR) communications by specifying a solution for interoperability and integration among Professional Mobile Radio systems (TETRA and Simulcast), public systems (GSM/GPRS/UMTS), and broadband wireless technologies, such as WiMAX. A policy for PSDR services scheduling and fundamental guidelines for mapping the quality of service over heterogeneous networks are presented. Hence, the paper outlines the key issues to be debated by a regulatory authority. Operation of the devised PSDR mobile integration solution is tested to ensure complete connectivity among users adopting different communication standards, as well as to enable distributed services provisioning guaranteeing always best connection to bandwidth demanding applications provided by an IP-based core network. Finally, the employment of the envisaged integration platform is detailed in Mobile Ad-Hoc and Wireless Sensor Networks.

Consumed power analysis for mobile radio system dimensioning

Cellular mobile radio networks are expected to increase the energy requirements due to their massive deployment. Then, it is required to improve their energy efficiency in order to favor the eco-sustainability and not to obstacle their economic impact. In this paper we study the impact of the power consumption in the design of mobile networks. The evaluation has been performed for GSM and LTE systems. The main aim is the analytical evaluation of the optimal cell radius accounting for the network sustainability and for both coverage and traffic constraints. Overall power consumption is expressed as the sum of static and dynamic terms. The former is due to BSs switch on and signaling, the latter is function of the traffic in the cell. The beneficial effects of power control on energy consumption are evaluated and compared with the non-power controlled case. Finally, reduction in power consumption for LTE respect to GSM is analyzed.

Performance evaluation of an opportunistic distributed power control procedure for wireless multiple access

In wireless ad hoc networks, effective spatial channel reuse can maximize the achievable throughput. To this aim, power-controlled multiple access MAC protocols seems to be a viable solution to allow a greater number of simultaneous transmissions on the same channel. In this paper, we propose an opportunistic distributed algorithm to increase throughput in ad-hoc networks by exploiting the spatial reuse deriving from the implementation of power controlled data transmissions. Performance is evaluated through simulation. Results show that a marked improvement of the aggregate channel utilization can be achieved with respect to the no power control schemes (such as in the typical IEEE 802.11 systems) by properly selecting the link margins for fading and interference.

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.

Test of 2.5 GHz WiMAX performances for business and SOHO in a multi-service environment

The paper is focused on evaluating the performances of a WiMAX system in a variety of single and multiple play scenarios for SOHO and Business customers. To this aim several experiments are carried out over a 2.5 GHz WiMAX test-bed deployed at the radiocommunication laboratories of the University of Rome Tor Vergata. Throughput and link quality are tested in uplink and downlink in correspondence of different system configuration profiles and WiMAX service classes. Fixed and portable access are considered, for coverage ranges up to a few kilometers.

Performance comparison of vertical handover strategies for psdr heterogeneous networks

In this article we suggest a vertical handover (VHO) solution able to optimize mobility management over heterogeneous networks in terms of handoff delay and signaling load. The presented strategy discriminates the best mobility protocol to be used based on a scheduling policy. It is specifically designed for an integrated network architecture to provide PSDR organizations using TETRA and TETRA2 systems with the capability to exploit WiFi and WiMAX broadband access technologies in order to enjoy advanced services. The article presents the operational scenarios where integration between TETRA and WiFi/WiMAX is needed and the main resulting benefits. Performances of the suggested VHO management scheme are described and evaluated against other protocol solutions.

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.

Opportunistic Spectrum Access based on underlay UWB signalling

Opportunistic Spectrum Access (OSA) is a promising solution to increase spectral efficiency in the Cognitive Radio (CR) framework. In OSA networks, unlicensed Secondary Users (SUs) need a Common Control Channel (CCC) to identify the spectrum opportunities, i.e., common spectrum holes unused by licensed Primary Users (PUs). To fulfill this requirement, the sharing of the spectrum sensing data via Ultra-wideband (UWB) has been proposed in the literature. In this paper we evaluate the design of a highly available underlay UWB signalling network for the exchange of sensing information among SUs avoiding harmful interference to PUs. We analyse the trade-off between the connectivity degree of a multi-hop underlay signalling network, related to the CCC parameters, and its coexistence with PUs. Moreover, we assess the performance of cooperative sensing in terms of detection probability accounting for the availability and the characteristics of the CCC. Results show that a correct dimensioning of the UWB signalling network allows to achieve high accuracy of PU detection avoiding harmful interference.