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The magic trick of the serious game approach lies in the fact that a positive aim can be reached by attracting people in an entertaining task. Yet, the real impact of this technology on our society will happen when it will be utilized to gather the contribution of thousands, maybe millions, of players all around the world to address crucial and unsolved problems. To this aim, we adopt the Web Squared paradigm, combining serious games with crowd-sourcing and automatic data gathering from smartphones' sensors. We show how this combination can create a major force able to tackle serious challenges considered too complex for single users and even for computers. As a proof-of-concept, we discuss a solution able to automatically generate a Google Maps-like service also including information about traffic lights with audible signals. As a final result, our solution improves crossroad accessibility for blind pedestrians by exploiting the latest Web Squared and serious game technology.

Nowadays it is common practice to handle any type of file with the personal computer. The introduction of mobile devices in modern life opened the doors to the possibility to do that ubiquitously, fostering a vast plethora of new entertainment applications. Unfortunately, the storage capacity of these devices is limited; it may hence be useful to have the possibility to store the files on the web and retrieve them at any time and anywhere. To satisfy this need, we have created FTP4Android. Our solution provides smartphone users with the illusion of having an infinite memory on their devices by storing their files on remote servers. To speed up the transfer process both in upload and download, parallel transmissions to/from different servers are performed. To demonstrate how this technology could be used for entertainment purposes, we have devised a treasure hunt application for mobile users based on our FTP4Android.

In the last decades mobile phones have evolved into powerful devices able to bring Internet services into our pockets. Following this trend, a popular application as gaming has extended its domain from home computers and consoles to the mobile realm. Indeed, mobile games embody a successful application for smartphones able to engage millions of subscribers worldwide. The next step is the creation of a new generation of mobile games, representing more than just a tiny version of home entertainment blockbusters; the ubiquitous use and the interesting features (i.e., camera, gyroscope, connectivity, GPS, etc.) of mobile phones create unprecedented opportunities for completely new kinds of gaming experience. As a proof of concept, we have created an application for mobile phones exploiting their camera and connectivity as available in every modern smartphone to digitally replicate and enhance an outdoor game for children that would not be playable through a desktop PC.

Most of future digital services for home and office users will be deployed and delivered through the Internet and wireless connectivity. However, employing regular access points (APs) and protocols will not allow an efficient coexistence among heterogeneous application flows. Indeed, real-time and elastic applications are (and will be) supported by different protocols and featured with different performance requirements: low perpacket delay for the former and high throughput for the latter. In this work, we present a work-in-progress evaluation of a new AP prototype able to guarantee a fast and smooth data delivery for real-time streams while maintaining a high throughput for TCP-based applications. Our approach is based on a userspace modification of the AP's code based on OpenWRT operating system so as to appropriately shape transiting network traffic. Preliminary experimental results confirm that our solution represents an optimal candidate to become the center of future wireless in-home scenarios.

From the advent of the digital era, new powerful technologies have shown, on one hand, important progresses towards the mankind necessity and, on the other hand, a progressive isolation of individuals. In this work, we present a social application we have developed to support people with disabilities. Our application leverages on the popularity of smart phones and on the Web 2.0 paradigm to pervasively and invisibly collect information about the accessibility or city roads. This information is then used to provide a Google Maps-like service to determine an accessible path between any two locations for users with a certain disability (e.g., people on a wheelchair).

Due to mobility, communication links between mobile nodes are transient and network maintenance overhead is a major performance bottleneck for data transmission. Low node density makes it difficult to establish end-to-end connection, thus impeding a continuous end-to-end path between a source and a destination. This creates a modern type of DTN, which was originally intended for communication in outer space, but is now directly accessible from our pockets. In this paper, we present a special purpose system for searching and transferring files tailored to both the characteristics of MANETs and the requirements of P2P file sharing. Our approach is based on an application layer overlay network. We port a DTN type solution into an infrastructure-less environment like MANETs and leverage peer mobility to reach data in other disconnected networks. This is done by implementing an asynchronous communication model, store-delegate-and-forward, like DTNs, where a peer can delegate unaccomplished file download or query tasks to special peers. To improve data transmission performance while reducing communication overhead, we select these special peers by the expectation of encountering them again in future and assign them different download starting point on the file.

Author address: University of Padua - Pure and Applied Mathematics, Via Trieste, 63 Padova, D 35131, Italy Permission to make digital or hard copies of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies show this notice on the first page or initial screen of a display along with the full citation. Copyrights for components of this work owned by others than ACM must be honored. Abstracting with credit is permitted. To copy otherwise, to republish, to post on servers, to redistribute to lists, or to use any component of this work in other works requires prior specific permission and/or a fee. Permissions may be requested from Publications Dept., ACM, Inc., 2 Penn Plaza, Suite 701, New York, NY 10121-0701 USA, fax +1 (212) 869-0481, or permissions@acm.org. ©2010 ACM 1544-3574/2010/12-ART23 $10.00 DOI: 10.1145/1921141.1921143 http://doi.acm.org/10.1145/1921141.1921143 ACM Computers in Entertainment, Vol. 8, No. 4, Article 23, Publication date: December 2010

Wireless Mesh Networks (WMNs) have the potentialities to greatly penetrate the marketplace in the next decade. They can be considered a hybrid between wireless infrastructure and ad-hoc networks; no other network infrastructure is needed other than the mesh points, thus providing flexibility in building and expanding the network, allowing for automatic discovery of neighboring nodes, increased reliability and redundancy. In this work, we discuss how WMNs can be practically employed to support wireless multihop communications in an office-wide area. To this aim, we have deployed a real WMN testbed utilizing state-of-the-art technology and analyzed the performance of this architecture when supporting multihop heterogeneous traffic.

Mobile phones have already evolved from simple voice communication means into a powerful device able to handle multimedia documents, personal productivity applications, and all sort of connections to the Internet. It is hence expected to see a popular application such as file sharing to become widely utilized even in this context. Indeed, the combination among mobile users and file sharing seems a match made in heaven: people could exchange files of interest just passing by each other. Moreover, new context related applications may be developed to exploit this possibility enriching our lives. In this work, we present design issues and implementation details about a real P2P file sharing application for mobile phones.

Social network communities are involving millions of users, representing one of the main reasons why people log on the Internet from their home computers. Part of this success is certainly due to the possibility for end users to reverse the traditional publisher/consumer model, achieving control over service consumption, and gaining the opportunity to produce multimedia contents instantaneously available worldwide. Social network communities are not destined to be confined in traditional wired networks. Indeed, mobile users could greatly benefit from applications that combine social networks and location-based multimedia services. It is hence of particular interest to consider the next frontier in wireless networking, i.e., vehicular networks, and imagine how community-based services could be provided in this highly variable context, enabling the sprouting of communities on the road. To this aim, we address here one of the specific challenges in this scenario, i.e., the fast delivery of service triggering messages generated by a user to a certain area where another user can provide the requested multimedia service (e.g., live video streaming, traffic updates, friends finder, status messages of social network applications). We discuss the state-of-art for this technical challenge and compare it against our solution, which is able to dynamically adapt to different transmission conditions as those featuring a vehicular network. In essence, the main innovation of our contribution amounts to a transmission range estimator that enables vehicles to know their current transmission range, independently from changes in the vehicular network topology, and use it to maximize the efficiency in transmitting service-triggering messages.

Online games represent one of the most important revenue sources for entertainment based companies and a challenging field in multimedia application research. With vehicular networks poised to become the new wireless frontier of the Internet, car passengers embody the next consumers that will be targeted by online game providers. Yet, the high mobility and heterogeneity of vehicular networks pose serious challenges; previous work on online games demonstrated the importance of the network’s performance in determining the quality level perceived by consumers. A main problem is related to competing heterogeneous network traffic generated by real-time multimedia applications and concurrent bulk data traffic sharing the same access points along the road. Such problem causes low responsiveness in the gaming application and is further exacerbated by the continuous variations in the number and type of flows, due to the cars’ mobility. To this aim, we show how smart access points can be deployed in infrastructure-based vehicular networks to ensure efficient coexistence among heterogeneous types of flow even in presence of frequent network traffic variations due to the vehicles’ high mobility. As a result, delivery delays are kept small, satisfying the main requirement for the deployment of responsive online games.

Nowadays, wireless connectivity is increasingly available in homes to support heterogeneous multimedia applications. However, with current off-the-shelf systems, real-time applications (e.g., video streaming, online games) suffer from delays caused by the interference with elastic (e.g., TCP-based downloading sessions) ones. Furthermore, simultaneous elastic application flows are not able to fairly share the same bottleneck, severely damaging those featured with long round-trip times (RTTs). In this article, we discuss how a solution based on a smart access point can actually solve these problems, ensuring low per-packet delays to real-time applications and both high and RTT-fair throughput to elastic ones. We discuss the experimental outcome of our solution showing the benefits achieved with respect to using the legacy protocols and even to adopting a TCP Vegas-based solution, known for providing the same goals we are aiming at.

Online games represent one of the most important revenue sources for entertainment based companies and a challenging field in multimedia application research. With vehicular networks poised to become the new wireless frontier of the Internet, car passengers embody the next consumers that will be targeted by online game providers. Yet, the high mobility and heterogeneity of vehicular networks pose serious challenges to the deployment of efficient online game services such as, for instance, continuous variations in the number and type of flows served by access points along the road. To this aim, we discuss a solution based on the deployment of smart access points along the road and demonstrate how this solution is able to smoothen network traffic conditions, ensuring coexistence among heterogeneous types of flow even in presence of frequent network traffic variations.

Multiplayer Online Games (MOGs) embody intensive applications that require smart solutions able to cope with the high network traffic generated by players, variable latencies, and system failures. To this aim, the anatomy of the game architecture should reflect the possibly wide geographical dispersion of players interacting in a game session. Whereas the use of mirrored game servers has been recognized as a scalable solution to support MOGs, yet, a critical aspect remains that of identifying an efficient synchronization scheme able to responsively guarantee the consistency of the redundant game state. To address this issue, we added intelligence to an optimistic synchronization scheme for mirrored game server architectures: our scheme is able to classify events and, based on their semantics, relax ordering and reliability constraints to gain responsiveness without sacrificing consistency. In this work, we describe the devised scheme and report on an experimental assessment that is based on a real implementation of a mirrored game server architecture, deployed over the Internet. Results definitively show the efficacy of our approach.

As virtual environments are becoming graphically nearly realistic, the need for a satisfying Artificial Intelligence (AI) is perceived as more and more important by game players. In particular, what players have to face nowadays in terms of AI is not far from what was available at the beginning of the video games era. Even nowadays, the AI of almost all games is based on a finite set of actions/reactions whose sequence can be easily predicted by expert players. As a result, the game soon becomes too obvious to still be fun. Instead, machine learning techniques could be employed to classify a player’s behavior and consequently adapt the game’s AI; the competition against the AI would become more stimulant and the fun of the game would last longer. To this aim, we consider a game where both the player and the AI have a limited information about the current game state and where it is part of the game to guess the information hidden by the opponent. We demonstrate how machine learning techniques could be easily implemented in this context to improve the AI by making it adaptive with respect to the strategy of a specific player.

Satellite networks have the potentiality to guarantee ubiquitous access to the Internet. Yet, their transmission delay and errors represent still a challenge for researchers and practitioners, especially when considering TCP-based flows. Having efficient means to estimate important channel features such as, for instance, the available bandwidth and the total capacity has been proven to be proficient in improving the performance in this context. To this aim we discuss SBE (Shareable Bandwidth Estimator), a solution able to provide a simple and effective estimation of the bottleneck link capacity minus the simultaneously present uniformly distributed traffic. Simulative experiments prove that our scheme is effective since the very beginning of a connection. Furthermore, SBE can be easily implemented as it requires only sender-side modifications and is based on regular TCP functioning. © 2008 IEEE.

The technology supporting Multiplayer Online Games (MOGs) has greatly improved in the past few years. This represents great news both for players all over the world and for researchers that are struggling behind tough problems in real-time distributed systems. Indeed, MOGs represent a peculiar class of distributed systems, sharing features, requirements, challenges, and thereby also feasible solutions. To this aim, we focus on issues and state-of-art solutions related to a crucial aspect in MOG deployment: the synchronization of its nodes. In particular, we review techniques able to guarantee that the system evolved in a quick and consistent way and highlight how they can be made more effective by exploiting specific game features. To further support this claim, we also present results from an experimental evaluation we performed.

Internet and the latest correlated technologies, such as Web 2.0, represent inventions that have changed the world with their social contribution. Yet, digital divide and cyber-balkanization are Internet's discriminatory phenomena well known by field experts. In addition, we want now to raise the attention on the actual employment of these technologies: the vast potential within the Internet is currently dispersed in millions of applications devoted to frivolous and egocentric utilizations. Being (almost) the only use people have made of the most pervasive communication system ever made, this represents an unacceptable waste of opportunities. To revert this trend, we propose a novel utilization paradigm of Internet technologies which is aimed at liberating part of resources that are captured but not used by egocentric applications to give them back to a possible common (and altruistic) use.

Interactive, mobile online games have recently become popular thus receiving the attention of researchers. Mobile games represent a particularly interesting case because of the proliferation of smart personal devices and the increasing availability of high speed wireless access points. With this vision, we propose a holistic solution that enables a top quality online gaming experience regardless whether the player is wired, wireless, or even mobile. Main components of this solution are: (i) a synchronization mechanism based on an Internet server overlay that enables interactivity, fairness, and scalability, and (ii) a smart access point able to support efficient coexistence between elastic (download) and real-time (game) traffic.

Massively multiplayer online games (MMOGs) are no longer a chimera. Everyday, new exemple of this application are released, available for free on the Web or on sale. Yet, high lags frequently affect MMOGs, annoying customers. This frustrating phenomenon is mainly due to the best-effort service provided by the Internet that is often responsible for congestion and loss of responsiveness. To address this challenging issue, we consider a mirrored game server architecture and present a mechanism aimed at accelerating the delivery of game events generated during game sessions. Our approach rests upon the use of an optimistic synchronization mechanism that exploits the semantics of the game to diminish the delivery time of game events, whilst maintaining the full consistency of the game state. Experimental results are reported confirming the adequacy of our approach.

A deep knowledge of TCP performance on the Internet al large is intimately related to understanding the role of the underlying path characteristics (bottleneck rate, buffer sizes, end-to-end delay, loss rate) on the performance of dynamic TCP flows. The practical way to study the TCP performance is by simulating on a dumbbell topology, Internet statistically equivalent cross-traffic along with simulated TCP, then extracting interest variables such as throughput as the indicator of performance. However, we advocate that much more can be learned about TCP performance by regenerating path characteristic conditions derived from traces, and let TCP flows run loose on top of it. In this study, we investigate several Internet public TCP flows, using LAN-specific traces (Berkeley LBNL (races), and we show how path characteristics can be extracted. We devise a new technique to obtain path capacity by searching longitudinal patterns of packet pairs on each TCP flow present in a trace. In addition, we look on buffer usage patterns based on effective throughput/estimated capacity ratio, as a way to relate KTT variation, packet loss and disclosure buffer sizes. Finally, the natural application is to test advanced TCP proposals on a per-trace scenario basis by regenerating dynamic traffic patterns directly from stored traces, such method is also called source-based traffic pattern. In this trace regeneration testbed, we have as input the TCP trace, then, a post-processing mechanism inferring path characteristics per flow. Finally, emulated virtual machines running in parallel enable the TCP traffic dynamics to run loose.

Real-time applications are going to play a major role in Vehicular Ad-hoc Networks (VANETs). In this context, nodes' IP addresses need to be automatically configured in a very small time and with a reduced need for re-configurations. Due to the very high mobility of vehicles, however, traditional mechanisms for address auto-configuration fail to perform well. Aimed at solving this problem, we propose a novel Leader-based scheme that exploits the topology of VANETs and a distributed DHCP service to guarantee fast and stable address configuration.

Since the expansion of their market and their challenging requirements, massively multiplayer online games are gaining increasing attention in the scientific community. One of the key factors in this kind of application is represented by the ability to rapidly deliver game events among the various players over the network. Employing in this context mirrored game server architectures and adapting RED (random early detection) techniques borrowed from network queuing management, we are able to show sensible benefits in upholding interactivity and scalability, whilst preserving game state consistency and game evolution fluency at the player's side

Ensuring fairness among players engaged in online games is a challenging task. Yet, it is a fundamental requirement that can make the difference between having customers that persist or desist in using this kind of application. Answering to this demand, we present here an event delivery mechanism among mirrored game servers able to effectively uplift the fairness degree during game sessions through the heterogenesis of ends in targeting interactivity. We also provide extensive results that sustain our claim.

Future digital entertainment services available to home users will share several characteristics: i) they will be deployed and delivered through the Internet, ii) a single media center will be exploited to orchestrate all parallel services, and iii) wireless technologies integrated within the home entertainment system will be massively utilized for the transmission of various data streams to networked devices. In this scenario, new effective strategies are needed to regulate the concurrent access to the wireless network when parallel applications generate different but simultaneous UDP/TCP-based flows. In this work, we present a novel technique aimed at guaranteeing a fast and smooth data delivery for real-time streams while maintaining a high throughput for TCP-based applications. Our approach is based on the utilization of a smart Access Point able to exploit available information about the ongoing traffic and existing features of the regular TCP. We compare the performance of our solution with an alternative one that makes use of an optimal setting of the 802-11 MAC layer parameters. Simulation results confirm that our smart Access Point represents an optimal candidate to be exploited in complex wireless scenarios for in-home entertainment.

Digital entertainment is going to be enjoyed at home through computer-centered services and broadband wireless connectivity. The hub of a home entertainment system will be based on a "magic box" able to handle all sort of multimedia data and deliver them in a fair and efficient way throughout the house. Unfortunately, with current systems, real-time applications (e.g., video streaming, online games) suffer from delays caused by the interference with elastic (e.g., downloading) ones. We provide insight on this problem and reveal the "special protocol potion" we blended to heal home entertainment systems from it. Indeed, our recipe is simply composed by i) an enhanced access point, ii) standard protocol features, and iii) a smart use of the available information on the on-going traffic. This way, we are able to achieve low per-packet delays and high throughputs, thus satisfying the requirements of both real-time and elastic applications. Most important to mention, our special potion is also free from side effects as it does not require modifications to Internet's protocols or architecture

The use of HAPS/UAV to enhance telecommunication capabilities has been proposed as an effective solution to support hot spot communications in limited areas. To ensure communication capabilities even in case of emergency (earthquake, power blackout, chemical/nuclear disaster, terrorist attack), when terrestrial fixed and mobile infrastructures are damaged or become unavailable, the access to satellites represents a reliable solution with worldwide coverage, even though it may suffer from shadowing impairment, especially in an urban environment. In this paper we approach an innovative and more challenging architecture foreseeing HAPS/UAV connected to the satellite in order to enlarge coverage and to allow interconnection with very remote locations. In this scenario, we have analysed TCP-based applications proposing some innovative techniques, both at protocol and at architectural level, to improve performance. In particular, we propose the use of a PEP technique, namely splitting, to speed up window growth in spite of high latency, combined with TCP Westwood as a very efficient algorithm particularly suitable and well performing over satellite links.

Online entertainment is now possible at home by means of a plethora of ubiquitous services that can be provided based on wireless technologies such as, for instance, the common Wi-Fi IEEE802.11g network technology. Yet a scarce attention has been devoted to study the impact of wireless MAC layer design choices on the native Internet transport protocols (e.g., TCP, UDP) during the distribution of in-house entertainment contents. We show that the current setting of the maximum number of retransmissions and the queue size in the IEEE802.11 protocol not necessarily corresponds to the optimal choice in this context. Based on the obtained results, we also provide directions in order to find the most efficient MAC layer setting.

The astonishing increase in the spread of the Internet has given rise to a globally connected community proficient at deploying online games for a large number of participants geographically located very far from each other. However, online games are characterized by more stringent requirements than traditional distributed applications deployed over the Internet can fulfill. Indeed, one of the key factors in determining the success of an online game is its ability to rapidly deliver events to the various game servers that maintain the state of the game over the network. We have already demonstrated [Palazzi et al. 2004] that in this context adapting RED (random early detection) techniques, borrowed from queuing management, can improve the global responsiveness of a game. However, this solution may not be sufficient for a specific class of online games. We deem that fast-paced multiplayer online games (such as shoot 'em ups, for example) in which participants have to behave frenetically, must guarantee a very high degree of interactivity, even at the cost of partially sacrificing the consistency of the game state. In this case having only a partially consistent view of the game state will not affect a player's amusement as much as delaying action-processing activity will. Hence we explore the possibility of applying a RIO-based (RED with in and out) algorithm to manage game delivery to the various game servers, in order to improve the degree of interactivity for fast-paced online games. Preliminary experimental results confirm the viability of our approach.

Since the first deployment of cellular phones, we have witnessed an almost global revolution in the development of wireless communication. This success has been evident for the GSM technology, whose popularity has exploded during the 1990s thanks to its affordable price, digital quality and a pervasive innovative application as SMS. However, the same positive condition seems to lack in the next generations of wireless communication, as UMTS, thus slowing down their market penetration. Therefore, both mature and recent mobile technology could benefit from the introduction of a novel application able to shake the market. To this aim, mobile location could be used to facilitate the diffusion of many novel services for cellular systems. We present in this paper, an innovative location based application that involves only a minor impact on the current GSM architecture, while offering to customers an appealing means to obtain multimedia entertainment.

The popularity of Video on Demand (VoD) services has recently grown to unprecedented levels. Even if UDP is often considered the standard transport protocol for video streaming, TCP is often used for VoD since its reliability, congestion control, and resilience to the presence of firewalls/NATs on the link. Unfortunately, poor video quality, frequent playback pauses, and delays due to slow frame buffering are still annoying users engaged in long RTT connections, both wired and wireless, with the server. This is due to the ack-based mechanism that increases the TCP’s congestion window, which leads to RTT-unfairness. As a practical consequence, if a VoD user is experiencing long RTTs while sharing the channel with another VoD user whose connection has small RTTs, the former will see a very slow progression of its video until the latter is done. In this paper, we propose the use of TCP Libra on VoD servers to resolve this RTT-unfairness issue, thus providing an efficient VoD service to any user, regardless of her/his RTTs.

New in-car communications and entertainment systems have emerged, enabling interconnection of various components in vehicles (e.g., TVs, CD/DVD players, media players, and cell phones). With the new advances of automotive industry, car passengers embody the next consumers that will be targeted by online game providers. In this context, researchers on online games demonstrated the importance of the network's performance in determining the quality level perceived by consumers. Enabling games over Vehicular Ad hoc Networks (VANET) will require the design of secure architectures against threats, in order to not jeopardize the effectiveness of online gaming over VANET. These threats could increase the delivery delay of game events, leading to the unsatisfaction of passengers. In this paper, we address security threats for online gaming over VANET. In particular, we focus on a representative vehicular broadcast algorithm, and we discuss a cheating threat. Indeed, the attacker could use the location-aware game message exchange to cheat about his position, thus enforcing game events to be delayed, and reduce the quality of service. Finally, we run a thorough set of simulations to assess the impact of the position cheating attack to the online gaming over VANET.

Online amusement applications, as distributed multiplayer videogames and interactive story telling, are gaining increasing attention both from entertainment industry and from scientific community. Providing a pleasant experience to players requires a rapid delivery of game actions among the various nodes in the network. A high playability degree should be guaranteed independently of the user's location, utilized device (PC, PDA, cellphone), type of connection (wired, wireless), and number of contemporary players. To this aim, we have devised an innovative approach to design the event delivery service for networked multiplayer game applications. Exploiting the semantics of the game, our scheme relaxes the ordering and reliability properties, upholding the interactivity level while preserving the game state consistency. The main contribution of our work is to show the benefits in event delivery synchronization obtained by employing, in this context, RED techniques borrowed from networking queuing management.

In case of emergency, when fixed infrastructures collapse, access to satellite resources might represent the only means of communication, even though, especially in an urban environment, shadowing can strongly reduce the visibility time. In addition, TCP based applications suffer from well know problems due to long latency. To improve performance we can act both at the architectural and protocol level. This paper considers an innovative architecture using HAPS (high altitude platforms station)/UAV connected to the satellite, thereby reducing the impairment of shadowing and introducing a short-range link with the user terminal; efficient TCP solutions allow use of standard equipment and applications without sacrificing performance. The combined use of both can greatly improve overall performance. The paper investigates how this innovative system architecture can be usefully employed in critical scenarios and provides a performance evaluation of TCP based applications using high data rate links.

After the digital TV switch-over, national spectrum regulators are considering opportunistic spectrum access techniques in the TV White Spaces (TVWS) frequency band. At present, the reference solution envisages the utilization of geolocation spectrum databases (GLDBs), in which spectrum availability is computed through complex propagation models. However, recent studies indicate that the used path loss model in GLDBs could be either inaccurate or too much conservative, possibly reducing the use of TVWS for opportunistic use by secondary networks. In this paper, we investigate the possibility to enhance the estimation accuracy of GLDBs with sensing reports produced by a swarm of Unmanned Aerial Scanning Vehicles (UASVs). These latter are able to explore the scenario in both space and frequencies, and to build a fine-grained shadowing map which can be used to tune the accuracy of propagation model used by GLDB. A novel distributed mobility algorithm is described for the sensing coverage of the scenario, and an aggregation mechanism for the map creation is illustrated. Simulation results confirm the effectiveness of our scheme in terms of TVWS detection accuracy and scenario coverage issues.

Recent studies demonstrate that Cognitive Radio (CR) technology can increase the spectrum efficiency of wireless systems, provided that the activity of primary users (PUs) must be carefully protected. For this reason, several sensing schemes leverage the cooperation among nodes to increase the accuracy of PU detection. In this paper, we propose to employ the CR principles in the vehicular environment in order to increase the spectrum opportunities for inter-vehicle communication (IVC). We propose a cooperative sensing and spectrum allocation scheme through which vehicles can share information about spectrum availability of TV channels on their path, and dynamically decide the channels to use on each road segment. Moreover, we investigate the role of vehicular mobility in the cooperation process, which might allow a vehicle to know in advance the spectrum availability on future locations along its path. Simulation results confirm the ability of our scheme in providing robust PU detection under fading conditions, and analyze the impact of some vehicular networks characteristics into the operations of CR systems.