Network edge environments like in-flight or in-train communications utilize satellite-terrestrial integrated networks. These networks however suffer from limited backhaul and cache resources, leading to sustainability issues due to increasing traffic demands. The problem becomes more challenging for 5G ecosystems, where applications have distinct requirements, rendering the management and orchestration of conventional satellite-terrestrial networks harder. Therefore, software-defined networking and edge network slicing are envisioned to enhance resource management and increase flexibility of resource allocation. However, the complexity of management and orchestration increases in cases where service providers, allocated to a slice, do not share information about their users with the infrastructure providers, due to privacy or other concerns. To incorporate the aspect of slice collaboration, we define network slices with respect to their willingness of sharing user traffic statistics with the infrastructure provider. Taking in-flight entertainment and connectivity services (IFECS) as an interesting 5G use-case, we introduce a system model mimicking the practical deployment of slicing for aircrafts using satellites. We propose a mixed integer non linear program that aims at maximizing the number of slices served. Utilizing our model we evaluate the deployment cost of slices with respect to cache and backhaul resources. Our results show that uncooperative slices have a lower selection probability. Nonetheless, we demonstrate that if the slice cost is paid by slice owners, uncooperative slices increase their chances of being served by 33%. Overall, cooperative slicing can revolutionize the IFECS system as it accommodates 200% more slices compared to uncooperative slicing.

Network programmability also sneaked into the mobile world leading to the emergence of Software-Defined Radio Access Network (SD-RAN) architectures. Interestingly, while only a small number of prototype architectures exist for SD-RAN, their performance evaluations are unfortunately also limited. Recent evaluations are carried out for small network dimensions of up to 50 devices, while emerging 5G/6G networks envision numbers of devices beyond 5000. Although 5G/6G applications are more stringent with respect to latency guarantees, performance evaluations of such low scale remain questionable. To fill this void, this paper presentsMARC: a novel benchmarking tool for SD-RAN architectures and their controllers. We useMARCto measure, analyze and identify performance implications for two state-of-the-art open source SD-RAN solutions:FlexRANand5G-EmPOWER. We perceive results for monitoring application scenarios considering fully centralized control. For this setting, our findings show that the proposed architectures with a single SD-RAN controller are not scalable and can even lead to unpredictable network operations. Using our tool and based on our insights, we provide and implement design guidelines for the internal working behavior of the existing controllers.

Network slicing is envisioned as a tool for 5G networks to provide network flexibility and isolation among different logical networks. While network slicing is well investigated in the fixed-network side, in the Radio Access Network (RAN) there remain challenging problems, which originate mainly from the stochastic nature of the wireless channels and complex resource coupling between slices. In this work, we investigate a network slicing problem for the downlink RAN of a cellular network. Our target is the reduction of resource usage while guaranteeing slice isolation and simultaneously accounting for each slice's average rate and delay requirements. We tackle the problem with a Lyapunov optimization approach, leading to a simple resource assignment procedure that we can prove to achieve isolation while satisfying all slice guarantees. The proposed procedure leads to a functional split, where resources are scheduled within each slice by a slice manager, while a Software-Defined RAN (SD-RAN) controller dynamically re-assigns resources to each slice. We verify our approach through extensive simulations and provide insight on how to fine-tune available system parameters.

Intent-based networking is a major component that will transform the manner in which the SDN/NFV-enabled future network infrastructures are operated. In particular, Intent-based networking is expected to play a major role in the multi-technological and software-defined 5G systems development roadmap. In this paper, we present the design and prototype implementation of an Intent-based mobile backhauling interface for 5G networks. Finally, we report on the empirical evaluation of of the proposed Intent-based interface over a small Enterprise WLAN. We also release the entire software stack under a permissive license for academic use.

The surge of mobile data traffic has spurred academia and industries to begin developing 5G networks. 5G is meant to overcome limitations of 4G cellular technology relying on the dominant trend of mobile network densification with the deployment of small cell base stations. To accelerate this process, low complexity and inexpensive remote radio heads (RRHs) are deployed massively and connected to a centralized pool of resources. In this work, we study the problem of inter-cell interference (ICI) which arises in frequency reuse one multi-tier 5G networks. We entrust the management of RRHs to a software-defined network controller and we take advantage of network functions virtualization. Our contributions consist of proposing Dynamic Strict Fractional Frequency Reuse (DSFFR), a method to relieve ICI which dynamically divides the small cell area in a different number of sectors. Furthermore, we formulate a joint scheduling problem composed of two schedulers which operate at different time granularity to transmit downlink packets. Modeling the coverage area with the tool of stochastic geometry and solving with simulations the joint scheduling problem, we are able to show that DSFFR outperforms the static scheme. Performances are addressed in terms of spectral efficiency and packet blocking probability.

Network Function Virtualization (NFV) is set to disrupt the current networking ecosystem by turning vertically-integrated middleboxes into software modules running on general purpose virtualized platforms. NFV will play a key role in future wireless and mobile networks where significant cost reductions can be obtained by virtualizing different layers and functions of the radio access and core network. Such goal raises several challenges in terms of both functional decomposition of the radio nodes and for the management and orchestration of the resulting network. In this work we present Scylla a high-level declarative language for programming network functions that allows programmers to implement per-flow custom packet processing. We also introduce a set of programming abstractions modeling the fundamental aspects of VNF orchestration. Finally, we present a proof-of-concept Controller and an SDK implementing the proposed abstractions.

Professional Mobile Radio (PMR) is a niche market which has been recently revitalized. Since public safety officers are required to operate in challenging or extreme conditions, radio communication is an essential asset to enable them to communicate with one another and with command centers organizing operations. We focus on an advanced deployment in which connectivity is provided by a temporary aerial-terrestrial network made of aerial and terrestrial nodes to create 4G LTE-A connectivity and to provision advanced data services in a geographical area of interest. In cases of scarce radio coverage of the aerial platforms, terrestrial nodes can conveniently act as relays to route traffic to/from the serving aerial base stations. We study connectivity and the service interruption time prior to reconnecting to a relay in a network consisting of 4G handhelds and relays. We study connectivity resorting to stochastic geometry, while modeling at the same time the amount of available resources at each relay node and radio signal propagation using the Okumura-Hata model for the urban environment. We will show that a region of space around a relay exists which allows us to optimize connectivity and minimize delay.

Key features of satellite communications such as wide-scale coverage, broadcast/multicast support and high availability, together with significant amounts of new satellite capacity coming online, anticipate new opportunities for satellite communications services as an integral part within upcoming 5G systems. To materialize these opportunities, satellite communications services have to be provisioned and operated in a more flexible, agile and cost-effective manner than done today. In this context, this paper describes a solution for the virtualization and dynamic orchestration of satellite communication services that builds on the introduction of Software Defined Networking (SDN) and Network Function Virtualization (NFV) technologies within the satellite ground segment systems. Along with the description of the main system architecture traits, the flowchart of a general procedure for the dynamic instantiation of virtualized satellite networks on top of a SDN/NFV-enabled satellite ground segment system is provided. The paper also presents experimental results for the dynamic customization of satellite network services through the implementation of a set of virtualized satellite network functions that can be orchestrated over general purpose open virtual platforms.

In this paper we study 3GPP mobility robustness in the context of Public Safety (PS) communications. In specific, we investigate the scenario in which 4G LTE connectivity is provisioned by means of Aerial evolved Node Bs (AeNBs) mounted on Low Altitude Platforms (LAPs) raised in the sky at an altitude ranging from few hundreds meters to one kilometer. Given the peculiarities of PS communications, the event of handover (HO) is particularly crucial for PS users. It is well understood that a trade-off exists between events of radio link failure (RLF) and HO completion, which is usually achieved by proper tuning of handover parameters. We propose a policy-based HO parameters adjustment in the form of a heuristic, which exploits the information provided by the Mobility Robustness Optimisation (MRO), in order to to achieve such a trade-off. Using simulations, we show that our heuristic solution can achieve the above mentioned trade-off, taking into account the different HO phases and incorporating a suitable Air-to-Ground (ATG) signal propagation model.

Network function virtualization (NFV) sits firmly on the networking evolutionary path. By migrating network functions from dedicated devices to general purpose computing platforms, NFV can help reduce the cost to deploy and operate large IT infrastructures. In particular, NFV is expected to play a pivotal role in mobile networks where significant cost reductions can be obtained by dynamically deploying and scaling virtual network functions (VNFs) in the core network. However, in order to achieve its full potential, NFV needs to extend its reach also to the radio access segment. Here, mobile virtual network operators shall be allowed to request radio access VNFs with custom resource allocation solutions. Such a requirement raises several challenges in terms of performance isolation and resource provisioning. In this work, we formalize the wireless VNF placement problem in the radio access network as an integer linear programming problem and we propose a VNF placement heuristic, named wireless network embedding (WiNE), to solve the problem. Moreover, we present a proof-of-concept implementation of an NFV management and orchestration framework for enterprise WLANs. The proposed architecture builds on a programmable network fabric where pure forwarding nodes are mixed with radio and packet processing capable nodes.

To cope up with the booming of data traffic and to accommodate new and emerging technologies such as machine-type communications, the 5th Generation (5G) of mobile networks must be empowered with efficient resource allocation schemes that benefit from the adoption of the Software-Defined networking (SDN) paradigm. In radio communications, allocation of resources is tightly connected with interference. In this paper, we revisit the way wireless interference is managed and avoided relying on the SDN paradigm for controlling the network. The SDN approach is exploited to expose the lower layers of the stack (e.g., Physical and Medium Access Control) to the controller and its applications by making system parameters available, such that it is possible to dynamically configure the network in a logically centralized fashion, by means of specifically designed algorithms. The contribution of this work is threefold. First, we show how to adapt the SDN paradigm to mobile networks. Second, we propose the interference graph as an abstraction that can be used to control interference. Last, we formulate a throughput optimization tool that uses the proposed interference graph as an input.

Network Function Virtualization (NFV) is emerging as one of the most innovative concepts in the networking landscape. By migrating network functions from dedicated mid-dleboxes to general purpose computing platforms, NFV can effectively reduce the cost to deploy and to operate large networks. However, in order to achieve its full potential, NFV needs to encompass also the radio access network allowing Mobile Virtual Network Operators to deploy custom resource allocation solutions within their virtual radio nodes. Such requirement raises several challenges in terms of performance isolation and resource provisioning. In this work we formalize the Virtual Network Function (VNF) placement problem for radio access networks as an integer linear programming problem and we propose a VNF placement heuristic. Moreover, we also present a proof-of-concept implementation of an NFV management and orchestration framework for Enterprise WLANs. The proposed architecture builds upon a programmable network fabric where pure forwarding nodes are mixed with radio and packet processing nodes leveraging on general computing platforms.

Software-Defined Networking promises to deliver more flexible and manageable networks by providing a clear decoupling between control plane and data plane and by implementing the latter in a logically centralized controller. However, if such principles are to be applied also to wireless networks, new primitives and abstractions capable of providing programmers with a global view of the network capturing channel quality and interference must be devised. Moreover, the dynamic radio environment necessitates fast adaptation of physical parameters such as power, modulation and coding schemes. So the wireless SDN abstractions should allow for such adaptations to happen closer to the air interface. In this paper, we present high level abstractions for channel quality, interference and network reconfiguration; the latter permits operations differing in timescales to be carried out at different controller entities. The proposed concepts have been implemented and evaluated over a WiFi-based WLAN. Empirical measurements show that the proposed platform can be used to implement typical WiFi network management tasks such as channel assignment and interference monitoring.

Network Function Virtualization (NFV) has recently been proposed as a tool to optimize the deployment of network functions by shifting the processing from dedicated middleboxes to general purpose and inexpensive hardware platforms. In this paper, we propose a novel NFV-based management and orchestration framework for enterprise WLANs. Our framework is compatible with the ETSI NFV architecture and leverages on hybrid nodes combining the forwarding capabilities of a programmable switch with the storage/computational capabilities of a server. We propose an algorithm for Virtual Network Function placement which optimizes the functions deployment according to application level constraints. A proof-of-concept implementation of the proposed framework and a preliminary performance evaluation of selected VNFs are also presented.

Software-Defined Networking (SDN) has received, in the last years, significant interest from the academic and the industrial communities alike. The decoupled control and data planes found in an SDN allows for logically centralized intelligence in the control plane and generalized network hardware in the data plane. Although the current SDN ecosystem provides a rich support for wired packet-switched networks, the same cannot be said for wireless networks where specific radio data-plane abstractions, controllers, and programming primitives are still yet to be established. In this work, we present a set of programming abstractions modeling the fundamental aspects of a wireless network, namely state management, resource provisioning, network monitoring, and network reconfiguration. The proposed abstractions hide away the implementation details of the underlying wireless technology providing programmers with expressive tools to control the state of the network. We also present a Software-Defined Radio Access Network Controller for Enterprise WLANs and a Python--based Software Development Kit implementing the proposed abstractions. Finally, we experimentally evaluate the usefulness, efficiency and flexibility of the platform over a real 802.11-based WLAN.

Programming wireless networks requires accounting for multiple complex operations, such as monitoring interference and allocating radio resources. Employing the Software-Defined Networking (SDN) paradigm eases the implementation of such tasks when augmented with suitable high-level programming abstractions. In this work, we present a set of programming abstractions modeling three fundamental aspects of a wireless networks, namely state management, resource provisioning, and network state collection. We also describe our proof-of-concept implementation of the proposed abstractions focusing on WiFi networks and show its use for realizing typical control tasks such as mobility management and traffic engineering as Network Apps.

The 4G Evolved Packet Core (EPC) is the pillar of the Long Term Evolution (LTE) mobile networks. Inspired by the current trend of designing distributed and more autonomous systems, we can notice that the complexity of the existing EPC seriously limits this possibility. We principally consider a reshaping of cellular networks in order to move towards virtual-distributed architectures allowing dynamic deployments of commercial/non-commercial, temporary or local networks. In this paper, we present Flexible Management Entity (FME), a distributed entity which leverages on virtualized EPC functionalities in 4G-LTE cellular systems. We highlight several conceptual and engineering trade-offs in realizing such a system.We also analyze the behavior and benefits of FME in various simulation settings that expose the dynamic deployment scenarios for 4G networks.

In this demo we present Joule, a software enabling real-time power consumption monitoring of networking devices without having to deploy physical meters in the form of, for example, managed Power-Over-Ethernet supplies. We will demonstrate how Joule can estimate the power consumption of commercial WiFi Access Points by exploiting observable network statistics and under different workloads, e.g. browsing, video streaming, and background FTP traffic. An interactive web dashboard will allow attendees to have a first hand experience on the correlation between traffic and power consumption.

Past years have witnessed the surge of mobile broadband Internet traffic due to the broad adoption of a number of major technical advances in new wireless technologies and consumer electronics. In this respect, mobile networks have greatly increased their availability to meet the exponentially growing capacity demand of modern mobile applications and services. The upcoming scenario in the near future lays down the possibility of a continuum of communications thanks also to the deployment of so called small cells. Conventional cellular networks and the small cells will form the foundation of this pervasive communication system. Therefore, future wireless systems must carry the necessary scalability and seamless operation to accommodate the users and integrate the macro cells and small cells together. In this work we propose the V-Cell concept and architecture. V-Cell is potentially leading to a paradigm shift when approaching the system designs that allows to overcome most of the limitations of physical layer techniques in conventional wireless networks.

Reliable power consumption metering is important for power consumption management and optimization in wireless access networks. As a matter of fact, it is estimated that by 2015 wireless access networks will account for about 90% of the entire wireless energy cloud footprint. This can be traced back to the massive deployment of WiFi hotspots in the recent years in order to partially offload cellular networks from the load generated by modern data hungry mobile applications. In such a scenario the first step in reducing the power consumption of any IT infrastructure is to acknowledge it. Production-level solutions for large-scale monitoring campaign do exist, in the form, for example, of managed Power Over Ethernet devices. These solutions are however expensive to install and to manage especially for large legacy deployments. To overcome this limitation we propose Joule a virtual power consumption monitoring solution capable of estimating in real-time the actual power consumption of WiFi Access Points. Field trials performed using various benchmarks and applications show that Joule can provide a precise estimation of the power consumed by a typical IEEE 802.11 Access Point.

Wireless sensor networks (WSNs) are meant to monitor natural and man-made phenomena, made of simple low cost sensors interconnected via low data rate communication links to survey wide areas. In this paper, we investigate the trade-off arising from spectrum occupation and packet delivery time in professionally installed wide area WSNs (WA-WSNs). We study two types of network topologies, namely star and mesh topologies, based on the recent IEEE 802.15.4k and multi-channel multi-radio IEEE 802.15.4g standards, respectively. We perform extensive packet level simulations of the mesh topology network, while keeping the star network as a benchmark. Our contribution is threefold. First, we address connectivity in the mesh network by deploying additional relay nodes, when necessary, to enable also each node with at least two independent route alternatives. Second, our simulation results show that the mesh topology requires 20% more spectrum to deliver the whole set of sensed data to the traffic sink compared with the star topology network under delivery time constraints. Finally, we show that only 10% of the nodes in the mesh network actually need additional spectrum and multiple radio transceivers to keep the delay bounded by that of the star topology.

In this paper, we investigate scenarios where 4G LTE base stations are mounted on balloons raised in the sky for the provision of cellular connectivity and coverage within an area of few kilometers (e.g., scenarios for emergency communications). In this context, the link between the base stations need to be completed using wireless technologies, thus impacting the performance of the X2 logical interface. We propose the adoption of a wireless backhaul link based on WiFi technology. The main contributions of this paper consist in: modeling the LTE handover over a WiFi link; analyzing the binary exponential backoff with a hands-on one-dimensional Markov Chain including a finite number of packet retries as well as accounting for packets corruption due to Rice fading; and showing the average handover latency and handover preparation failure probability, thus proving that WiFi can meet LTE handover constraints in the majority of the investigated cases.

Energy efficiency in wireless networks has become an important field of research due to ever increasing energy expenditure in battery supplied mobile terminals. In this paper we present an energy efficient routing scheme for multi-standard infrastructure wireless networks based on multi-hop cooperative relaying. The aim of the proposed technique is to exploit short-range cooperation to take benefit from mobile terminals having superior links thus enable energy efficiency. Performance results show that higher data-rate yielded by cooperation can compensate the expense of higher energy due to multiple interfaces active on the same mobile terminal, making possible to observe energy efficiency gain of the system. A maximum achievable energy efficiency gain of up to 42 % was observed in our simulations when using the cooperative short range routing technique.

Energy efficiency is acknowledged as a pivotal issue for a sustainable development of wireless networking technologies. Traditionally, most works in the area focused on the user equipment, where battery duration represents a key asset. However, as the smartphone and tablet revolution fuels a massive deployment of wireless networks, often in the form of WiFi hotspots, more and more attention is expected to be devoted to the energy-efficient management of wireless access infrastructure. These networks tend to be dense and over-provisioned, which in time leads to significant energy wastage in off-peak conditions. In this paper, we present MORFEO a flexible energy-saving decision algorithm to tune the energy consumption of a wireless infrastructure to the actual network conditions in terms of both user density and traffic patterns. Experimental results from a real-life deployment shows that our solution can deliver significant energy savings with minimal degradation in terms of the quality of service provided.

The energy wasted in wireless networks is a serious concern and the main challenge lies in determining when and where the energy is wasted. In this demo, we present Energino, an energy measurement and control system designed to deliver high performance while remaining a cheap solution.

Wireless Sensor Networks (WSNs) provide an extensible and effective means to monitor large and geographically diverse areas. Nodes in a WSN are characterized by very strict constraints in terms of computing power and energy consumption, as a result of which efficient and secure data aggregation techniques are being proposed as enabling technology for reducing network load, while at the same time providing high sensing accuracy and data integrity. In this paper, we present an hybrid mesh/sensor network architecture based on a sharing of tasks between mesh routers and sensor nodes. Our architecture is particularly suitable to realize an application agnostic mesh backhaul, able to concurrently support multiple WSNs while ensuring both end-to-end encryption and hop-by- hop authentication. Simulation analyses have shown that the proposed scheme can significantly reduce the network load while preserving data confidentiality and integrity. Finally, a real-world prototype has been implemented and tested over a small scale testbed confirming the simulation results.

Multi-hop wireless systems represent a viable means for deploying access networks covering medium-size areas with limited investment, making use of commodity hardware and freely available software suites. At the same time, management of such networks represent an overly complex task, due to the joint effect of the time-varying nature of the radio channel, user mobility and the inherently distributed nature of the system. A number of solutions are currently being researched, whereby network management functionalities get embedded within the wireless network itself simplifying both the initial network deployment and its subsequent maintenance by removing the need for a dedicated network controller which can be expensive in that it requires dedicated hosting facilities, power, and adequate cooling. A common building block of such approaches is represented by a monitoring framework able to bring the relevant network-level information to the decision points. In this paper, we present a distributed network monitoring toolkit, specifically developed for wireless multi-hop networks. The toolkit allows network administrators to monitor the status of the network as well as to plan and execute active measurement campaigns. Information is stored in a distributed network-wide repository and is accessible through a web interface.

In this paper, we present the Airtime Deficit Round Robin (ADRR), a novel scheduling algorithm for IEEE 802.11-based wireless networks. The ADRR mechanism enhances the Deficit Round Robin scheduling discipline by taking into account the channel quality experienced by the transmitting node. The devised algorithm addresses the IEEE 802.11 performance anomaly, preventing a node which experiences poor channel conditions from monopolizing the wireless medium, lowering the performance of the whole system. The proposed approach combines link scheduling with measurable routing metrics. Simulation analyses have shown that the proposed scheme can achieve performance isolation among links characterized by heterogeneous channel conditions. A real prototype has been implemented and evaluated over a small scale testbed confirming the simulation results.

Aerial telecommunications networks based on Low Altitude Platforms (LAPs) are expected to optimally meet the urgent needs of emergency relief and recovery operations for tackling large scale natural disasters. The energy efficient operation of such networks is important given the fact that the entire network infrastructure including the battery operated ground terminals, exhibit requirements to operate under power constrained situations. In this paper, we show that the cooperation between mobile terrestrial terminals on the ground could improve the energy efficiency in the uplink depending on the temporal behavior of the terrestrial and the aerial uplink channels. We consider cognitive context aware capabilities that could be utilized to improve the overall lifetime of the mobile ground terminals by dynamically adapting between direct and cooperative relay links. We also discuss a novel network architecture constituted of an integrated and highly dynamic multi-purpose aerial-terrestrial communications infrastructure that can be contextually extended with fast-deploying aerial platforms for emergency communications.

In order to provide the user with the best quality of experience, handling network heterogeneity is essential. In this paper, we investigate the design of a cross layer architecture for scalable video streaming applications in the context of heterogeneous broadband networks. We use the data rate adaptation feature in the video streaming application to meet the destination MAC/physical layer conditions and resource availability. Resources include the end-to-end available bandwidth between the source video server and customers from heterogeneous networks including WiMax, WiFi, 3G, and wired networks. We also introduce an enhanced admission control function at the destination gateway (to which the destination is attached) that takes into account video adaptability property. In order to illustrate the effectiveness of our mechanism, we implemented our solution named CLO (Cross Layer Optimizer) in the QualNet simulator over a WiMAX network. We utilize the existing MAC management messages exchanged between base and subscriber stations (BS and SS) and provide them to the video streaming application via a specific CLO interface. In order to assess the performance of CLO, we conducted extensive simulations using a personalized scalable video traffic generator, capable of providing different video data rates. The simulation results confirm remarkable improvement in the quality perceived by the user.

In next generation wireless systems, achieving seamless service continuity when transitioning between heterogeneous networks is a challenging task. An approach to optimize these handover procedures through the introduction of a standardized framework is followed by the IEEE 802.21 working group. The Media Independent Handover (MIH) function of IEEE 802.21 is mainly designed for "client-network" scenarios and not applicable to multi-hop connectivity models. In this paper, we propose an extended MIH model for accommodating multi-hop mode of operation in heterogeneous mobile networks. Our objective is to effectively use the services and the messages associated to the framework, so as to enhance the scope of MIH functionality and contrastingly, enable multi-hop heterogeneous networking in personal ubiquitous environments.

There is an increasing acceptance for Wireless Mesh Networks (WMN) as the potential `last-mile' access technology running media-rich applications with stringent quality of service (QoS) requirements. As WMNs are envisioned to provide high bandwidth broadband services to a large community of users, the Internet Gateway which acts as a central point of attachment for the mesh routers is likely to be a potential bottleneck because of its limited wireless link capacity. We propose TBMGA (Tree-Based with Multi-gateway Association), a novel routing protocol that elegantly balances the load among the different Internet gateways in a WMN. With TBMGA, we combine the flexibility of layer-2 routing with the self-configuring and self-healing capabilities of MANET routing. TBMGA switches the point of attachment of an active source-serviced gateway depending on a global metric estimated based on the average queue length and expected availability at the Internet gateway. The protocol is evaluated using simulations and we observe that the proposed scheme is able to efficiently balance the traffic between multiple gateways.

Next generation wireless systems are characterised by IP-based infrastructure with heterogeneous access technologies which complements each other in terms of data-rate and coverage. Users in this context are equipped with multi-functional mobile devices, enabling access to different networks. The proliferation of these devices ranging from mobile communication to home electronics and their inter-working forms a ubiquitous environment around the user. The personal ubiquitous environments (PUE) concept allows the user to have ubiquitous global access to a vast number and variety of information resources without dwelling into the diversity of devices and networks. In this paper, we present the PUE mobility management (MM) architecture that enables global seamless roaming in All-IP heterogeneous wireless networks. The PUE mobility management architecture is further evaluated (with the help of simulations) under a variety of everyday usage scenarios and the proof-of-concept is presented. Our simulation results show that the PUE MM architecture efficiently manages the resources available in the userpsilas PUE and offers seamless handover experience in always changing, heterogeneous all-IP wireless networks.

An ever-growing demand for coverage extension, higher data-rates and improved connectivity has motivated the interconnection of mobile ad-hoc networks to fixed IP networks, to form a Hybrid Wireless Network (HWN). The convergence of ad- hoc and infrastructure network is also attractive in real-world scenarios due to its practicality and usefulness. In HWNs, gateways are generally used as an interconnection point for the integrated network. In order to improve the overall performance of HWN, an efficient gateway discovery and route maintenance scheme is indispensable. In this paper, we present a novel adaptive gateway discovery scheme called ADD (Adaptive Distributed gateway Discovery), in which the adaptation is done in a fully distributed manner. Simulation results show that the distributed adaptation capabilities of our proposed scheme facilitate outperforming the existing gateway discovery mechanisms in terms of control overhead, packet delivery and delay.

The rapid proliferation of mobile devices has influenced the potential growth of wireless networking applications. This has lead to an augmentation in wireless ad hoc networking scenarios, particularly interesting for network operators. In this work, we present an adaptive framework for weight metric estimation and dissemination to construct stable and reliable weight-based clusters which can provide faster convergence rates and performance results for dynamic routing in mobile ad hoc networks. The framework considers critical node properties in determining a node's suitability for becoming clusterheads. It employs adaptive cluster radius and dynamic network constraints as the weight dissemination criterion. We observe that the proposed algorithm is suitable for scalable ad hoc networks and provides stable cluster formation decisions based on weighted metric approaches. Extensive performance evaluations confirm the suitability of the protocol for adaptive stable cluster formation and control overhead reduction in mobile ad hoc networks. We also provide comparisons with other clustering algorithms.

The proliferation of heterogeneous devices, ranging from mobile communication to home electronics and their internetworking have resulted into the development of a "personal ubiquitous environment" around the user. In this increasingly complex world, personal networks (PN) and personal network federations (PN-F) provide simple but powerful concepts towards the vision of "personal ubiquitous environments". This paper proposes solutions to realise the concepts of PN and PN-F. To this end, we first present the integrated convergence (ICON) layer which offers seamless interoperability across heterogeneous access technologies at mobile nodes in PNs. Then, we introduce the personal network routing protocol (PNRP) for personal ubiquitous environments. We also provide the implementation and the evaluation of PNRP. Our results show that PNRP efficiently manages the user's personal environments i.e. PNs and PN-Fs. Moreover, in terms of delay and packet delivery fraction, it performs almost similar to the traditional routing protocols such as OLSR and AODV. In contrast, PNRP consistently generates less routing load than any flat proactive MANET routing protocol.

In this paper, we study the scalability of OLSR (Optimized Link State Routing) protocol, adapted for Multi-hop Mobile Ad Hoc Networks. We present a modified OLSR routing protocol, G-OLSR (Grid-OLSR) which incorporates the advantages of topology-based and position-based routing. The protocol has been designed to serve easier and robust ad hoc network deployments interesting for network operators and service providers, supporting mission-critical applications and innovative services as well as for fully distributed scenarios interesting for spontaneous deployments and mesh-type wireless multi-hop networks. The simulation results corroborates that the proposed schemes performs better than the OLSR routing scheme and from the analyses, we could interpret that G-OLSR is more suited for scalable mobile ad hoc networks.

The proliferation of heterogeneous devices, ranging from mobile communication to home electronics and their internetworking have resulted into the development of a "personal ubiquitous environment" around the user. In this increasingly complex world, personal networks (PN) and personal network federations (PN-F) provide simple but powerful concepts towards the vision of "personal ubiquitous environments". In this paper, we present the profile-based network layer design to realise the federations of personal networks. To this end, we introduce the possible architectures for PN federations and their initiation, formation and usage procedures, which are assisted by personal network profiles. Moreover, we also discuss the PN cluster formation procedure, which is performed by personal network routing protocol (PNRP). For the implementation and the evaluation of our proposed solutions, we particularly focus on spontaneous PN-F architecture. The proof-of-concept is given and the performance of our spontaneous PN-F scheme is evaluated.

Vehicular networks are the major ingredients of the envisioned Intelligent Transportation Systems (ITS) concept. An important component of ITS which is currently attracting wider research focus is road traffic information processing. This has widespread applications in the context of vehicular networks. The existing centralized approaches for traffic estimation are characterized by longer response times. They are also subject to higher processing requirements and possess high deployment costs. In this paper, we propose a completely distributed and infrastructure-free mechanism for road density estimation. The proposed solution is adaptive and scalable and targets city traffic environments. The approach is based on the distributed exchange and maintenance of traffic information between vehicles traversing the routes. The performance analysis of the proposed mechanism shows the accuracy of the algorithm for different traffic densities. It also gives insights into the promptness of information delivery in the mechanism based on delay analysis at road intersections. This promptness is a necessary condition to various applications requiring reliable decision making based on road traffic awareness.

The rapid proliferation of wireless devices has lead to an augmentation in mobile ad hoc networking scenarios, particularly interesting for commercial applications and to network operators. Scalability of ad hoc networks, with respect to routing has been an important research issue recently. It is well known that clustering is the commonly agreed upon solution for efficient routing, topology management and resource utilization in a large scale mobile ad hoc network topology. This paper proposed a hybrid routing mechanism for cluster-based ad hoc networks, realized through a novel cluster-quality based routing approach. The main goal of our scheme, which employs a hybrid approach, is to guarantee efficient cluster-to-cluster routing by optimizing cluster-route selection. To achieve this, we introduce a new cluster-quality metric, which is an indirect quality-of-service metric that can estimate the current performance state of participating clusters. Since, traditional QoS metrics are hard to estimate in ad hoc networks and all the more challenging in a dynamic clustered network environment, the objective is to have a better adapted mechanism for providing guaranteed routing. The authors also present an optimization algorithm for intra-cluster routing and to reduce the cluster re-organization overhead. The proposed scheme is evaluated through simulations, and the results indicate that our protocol scales well with increasing node-count, node-density and node-speed. The effectiveness of the cluster-quality metric is also studied.