Giuseppe Ruggeri

Performance evaluation and comparison of G.729/AMR/fuzzy voice activity detectors

The paper proposes a performance evaluation and comparison of G.729, AMR, and fuzzy voice activity detection (FVAD) algorithms. The comparison was made using objective, psychoacoustic, and subjective parameters. A highly varied speech database was also set up to evaluate the extent to which VADs depend on language, the signal-to-noise ratio (SNR), or the power level.

E-CHANET: Routing, forwarding and transport in Information-Centric multihop wireless networks

Information-Centric Networking (ICN) is a promising architecture for the future Internet that focuses on content rather than IP addresses. By leveraging named-data instead of named-hosts, ICN does not need the set up and maintenance of stable paths between end-nodes. This makes ICN particularly convenient in networks characterized by intermittent connectivity and hostile propagation conditions, such as wireless multihop networks like ad hoc and mesh networks. In this paper, we present an information-centric architecture for IEEE 802.11 wireless ad hoc networks, named E-CHANET, which performs routing, forwarding and reliable transport functions, specifically tailored to cope with the limitations and requirements of wireless distributed environments. E-CHANET performance is evaluated through simulations and a comparison with the legacy TCP/IP architecture and the basic CCN model is provided. Achieved results demonstrate the effectiveness of the proposed solution in mobile wireless environments.

Content-centric wireless networking: A survey

Abstract Content-Centric Networking (CCN) is a candidate future Internet architecture that gives favourable promises in distributed wireless environments. The latter ones seriously call into question the capability of TCP/IP to support stable end-to-end communications, due to lack of centralized control, node mobility, dynamic topologies, intermittent connectivity, and harsh signal propagation conditions. The CCN paradigm, relying on name-based forwarding and in-network data caching , has great potential to solve some of the problems encountered by IP-based protocols in wireless networks. In this paper, we examine the applicability of CCN principles to wireless networks with distributed access control, different degrees of node mobility and resource constraints. We provide some guidelines for readers approaching research on CCN, by highlighting points of strength and weaknesses and reviewing the current state of the art. The final discussion aims to identify the main open research challenges and some future trends for CCN deployment on a large scale.

Improving QoS and throughput in single- and multihop WLANs through dynamic traffic prioritization

Nowadays, research efforts are being put into the design of effective mechanisms to provide service quality differentiation in IEEE 802.11-based wireless LANs. In this article we analyze the effects of augmenting the contention-based channel access mechanism of IEEE 802.11e through the assignment of dynamic traffic priorities, that adapt to either the applications quality requirements or the network congestion status. The aim is to show the effectiveness and robustness of the proposed dynamic mechanism in a wireless ad hoc network, in both single-hop and multihop scenarios, under variable traffic and network load conditions.

End-to-end QoS provisioning in 4G with mobile hotspots

The novel concept of mobile hotspots, characterized by a group of wireless users equipped with wireless LAN cards, moving as a whole and requiring Internet connectivity, is gaining the interest of the telecommunications research community. This article intends to contribute to this research topic by proposing alternative solutions for the deployment of a mobile gateway device offering 3G connectivity to the group of WLAN users while they are moving. This is a decisive aspect of the 3G migration to 4G networks. The proposed solutions allow for two-hop wireless paths between WLAN and 3G systems, and performing control over-high layer issues, specifically focusing on end-to-end QoS provisioning. The pros and cons of envisaged design solutions are addressed and their relevance justified considering purposes, target users, and applications.

SMaRTCaR: An integrated smartphone-based platform to support traffic management applications

A massive research effort is recently going in the direction of interfacing cars with smartphones to offer value-added services to driver and passengers. Such an interest is motivated by the large popularity of smartphones and by the observation that vehicles can act as effective collectors of information from the surrounding environment. Indeed, modern cars are endowed with several sensors forming an in-vehicle network, which provides kinematics information, automotive diagnostic services, etc. Cars can be further equipped with external sensing devices to monitor specific physical parameters, such as pollution, humidity, temperature, etc. If properly collected and delivered, such data can contribute to make the road transport greener, smarter, and safer. With the purpose of supporting and improving data collection and distribution, in this paper a smartphone-based platform is designed that exploits low-cost dedicated hardware to interact with sensors on board and in the vehicle surroundings. Retrieved data are classified and then opportunistically transmitted via the most convenient wireless interface to the specific remote control and monitoring center. A prototype is also developed to assess the technological feasibility of our conceived platform.

Performance evaluation and comparison of ITU-T/ETSI voice activity detectors

The paper proposes a performance evaluation and comparison of recent ITU-T and ETSI voice activity detection algorithms. The comparison was made using both objective and psychoacoustic parameters, so as to have reliable judgements that were close to subjective ones. A highly varied speech database was also set up to evaluate the extent to which VAD depend on language, the signal to noise ratio, or the power level.

A WAVE-Compliant MAC Protocol to Support Vehicle-to-Infrastructure Non-Safety Applications

IEEE 802.11p is an emerging standard intended to support wireless access in the vehicular environment and to deliver both safety and non-safety applications to vehicles on the roads. Despite the numerous research works related to the design of reliable and timely dissemination of safety messages among vehicles, only a few works have investigated on-the-road delivery of non-safety data traffic, such as QoS-sensitive comfort and entertainment applications (e.g., multimedia, web browsing, e-mails, e-maps). In this paper, we propose a novel MAC protocol, W-HCF (WAVE-based Hybrid Coordination Function), which targets at the support of non-safety applications in vehicular environments. It is fully compliant with the IEEE 802.11p/WAVE (Wireless Access for Vehicular Environment) operational mode. Simulation results show that W-HCF outperforms the legacy IEEE 802.11p protocol in a vehicle-to-infrastructure communication network, and that it is able to match the requirements of applications in terms of goodput and delay. Index Terms—MAC, EDCA, HCCA, vehicular network, WAVE, QoS

Information-centric networking for M2M communications

The European Telecommunications Standards Institute (ETSI) recently released a set of specifications for a reference architecture to globally access resources provided by machines over heterogeneous technologies in an interoperable way through a RESTful interface. Resources are named through Uniform Resource Identifiers (URIs) at the application layer and typically reachable at the network layer through IP connectivity. Such an approach can be used also to access extremely resource-constrained devices, provided that lightweight interactions with a gateway, remotely exposing their resources, are granted. Among potential alternatives to support communication between the gateway and such constrained devices, we investigate the Information-Centric Networking (ICN) paradigm, gaining momentum in the future Internet research arena. It differs from the host-centric IP networking in that it cares for the content to retrieve instead of the device hosting it. By directly using content names at the network layer and a receiver-driven communication, ICN well fits the requirements of many machine-to-machine (M2M) applications that are information-centric in nature and rely on a publish-subscribe service model.In this paper, we propose an ICN-based solution to be deployed on top of constrained devices whose named resources are exposed at a wide area scope by an M2M gateway. The proposal aims at ensuring easy interoperability with ETSI M2M specifications, thus allowing remote applications to access the resources of ICN-enabled nodes. To showcase the viability of our proposal, a test-bed has been deployed leveraging low-cost devices for home automation. Experimental results confirm a good performance in terms of device resources consumption, easiness of implementation and latency of communication.

Providing Throughput Guarantees in 802.11e WLAN Through a Dynamic Priority Assignment Mechanism

Supporting real-time and interactive traffic in addition to traditional data traffic with a best-effort nature represents a constantly rising need in any kind of telecommunications environment. The IEEE 802.11 based WLAN (Wireless Local Area Network) environment does not represent an exception. This is why at different protocol layers, and primarily at the MAC layer, many efforts are being put by both the research community and the standardization bodies to design effective mechanisms for user QoS (Quality of Service) differentiation. Although early results are coming into sight, such as, for example, the IEEE 802.11e standard release, still a thorough research activity is required. Aim of the present paper is to contribute to the cited research issue by proposing an improvement to the “static” traffic prioritisation mechanism foreseen by the IEEE 802.11e MAC (Medium Access Control) protocol. This latter shows a twofold drawback. First, there is no certainty that QoS requirements relevant to a given application are always fulfilled by the “statically” associated priority. Second, resource requests of the applications are not adapted to the (usually highly) variable traffic conditions of a distributed WLAN environment. The algorithm we propose is specifically tailored to “dynamically” assign 802.11e MAC priorities, depending on both application QoS requirements and observed network congestion conditions. It is carefully designed, implemented into a system simulation tool, and its highly effective behaviour assessed under variable traffic and system conditions.