Antonio Pietrabissa

MQ-Routing

Mobile-Ad-Hoc-Networks (MANETs) are self-configuring networks of mobile nodes, which communicate through wireless links. The main issues in MANETs include the mobility of the network nodes, the scarcity of computational, bandwidth and energy resources. Thus, MANET routing protocols should explicitly consider network changes and node changes into the algorithm design. MANETs are particularly suited to guarantee connectivity in disaster relief scenarios, which are often impaired by the absence of network infrastructures. Moreover, such scenarios entail strict requirements on the lifetime of the device batteries and on the reactivity to possibly frequent link failures. This work proposes a proactive routing protocol, named MQ-Routing, aimed at maximizing the minimum node lifetime and at rapidly adapting to network topology changes. The proposed protocol modifies the Q-Routing algorithm, developed via Reinforcement Learning (RL) techniques, by introducing: (i) new metrics, which account for the paths availability and the energy in the path nodes, and which are dynamically combined and adapted to the changing network topologies and resources; (ii) a fully proactive approach to assure the protocol usage and reactivity in mobile scenarios. Extensive simulations validate the effectiveness of the proposed protocol, through comparisons with both the standard Q-Routing and the Optimized Link State Routing (OLSR) protocols.

Design of a bandwidth-on-demand (BoD) protocol for satellite networks modelled as time-delay systems

Bandwidth-on-demand (BoD) access protocols address the problem of guaranteeing a high exploitation of the valuable satellite bandwidth in the presence of large amount of data traffic accessing the satellite network. The novelty of the proposed BoD scheme consists in the use of control theory concepts to model the satellite network as a time-delay system and to generate the bandwidth requests. The proposed scheme, based on the internal model control and on the Smiths principle, yields the following advantages: (i) when the network is not congested, it provides upper-bounds to the queue lengths and to the queuing delays of the satellite terminal buffers; (ii) it is capable of recovering from congested states; (iii) it is independent of the statistical characteristics of the traffic entering the satellite network; (iv) the requests are such that the satellite terminals have always enough traffic to use all the requested bandwidth (so that no bandwidth is wasted). The paper includes simulations showing the effectiveness of the proposed BoD scheme. The work underlying this paper has been performed within the GEOCAST project belonging to the fifth framework Information Society and Technology programme of the European Union.

A cognitive future internet architecture

This Chapter proposes a novel Cognitive Framework as reference architecture for the Future Internet (FI), which is based on so-called Cognitive Managers. The objective of the proposed architecture is twofold. On one hand, it aims at achieving a full interoperation among the different entities constituting the ICT environment, by means of the introduction of Semantic Virtualization Enablers, in charge of virtualizing the heterogeneous entities interfacing the FI framework. On the other hand, it aims at achieving an inter-network and inter-layer cross-optimization by means of a set of so-called Cognitive Enablers, which are in charge of taking consistent and coordinated decisions according to a fully cognitive approach, availing of information coming from both the transport and the service/content layers of all networks. Preliminary test studies, realized in a home environment, confirm the potentialities of the proposed solution.

A distributed multi-path algorithm for wireless ad-hoc networks based on Wardrop routing

Wireless ad-hoc networks are collections of devices which are able to communicate each other through wireless links. Those networks differ from infrastructure-based wireless networks for the absence of a centralized coordinator which handles all the communications among the devices. This leads to higher probability of packets collision, congestion of links, etc. Moreover, wireless links are characterized by an intrinsic high and time varying packet loss ratio, due to external noise and interferences. The objective of this paper is to present a new distributed multi-path algorithm (i.e., traffic is split among multiple paths) for wireless ad-hoc networks with the aims of (i) increasing the throughput of the applications running onto the network (ii) explicitly accounting for the packet loss of the wireless links and (iii) guaranteeing that the routing process converges to stable paths. The algorithm is developed by using the concept of Wardrop equilibrium. Simulation results show the higher throughput achieved by the proposed routing algorithm, compared to shortest path routing protocols, based on hop count and on packet loss metrics.

An Alternative LP Formulation of the Admission Control Problem in Multiclass Networks

Communication networks support an increasing number of classes of service (CoS). Admission control strategies can be planned within the Markov decision process (MDP) framework; with the linear programming (LP) formulation of the MDP, class level requirements are explicitly controlled. Scalability problems with respect to the number C of CoSs arise with the standard LP formulation. This note proposes an alternative LP formulation, which is more scalable: the problem size reduction is 0((C+ 1)2/2C).

A robust adaptive congestion control for communication networks with time-varying delays

This work presents a congestion control for high-speed networks in the single bottle-neck case with time-varying multiple delays, aimed at avoiding congestion by setting the rates of the traffic flows. The novelty of this paper is that the controller explicitly deals with saturated (i.e., non persistent) sources. The controller consists in a main controller based on classical control theory coupled with a controller based on fuzzy logic: the former works properly when the sources are not saturated; the latter provides a saturation compensation by setting an adaptive multiplicative gain which acts on the rate command. The scheme provides also robust stability to time-delay uncertainties. Simulations prove its effectiveness.

On-board stochastic control of Electric Vehicle recharging

This paper deals with the design of an on-board control strategy for Electric Vehicle recharging under the hypothesis of missing knowledge of the future energy price and the presence of vehicle to grid capability. For this purpose the charging session is modeled as a finite horizon Markov Decision Process and the optimal charging policy is computed according to Reinforcement Learning techniques, the learning phase makes use of the revenues received when taking actions in states represented by the current level of charge, the leftover charging time and the last realization of energy price. Simulation results show the effectiveness of the proposed approach with respect to the fulfillment of driver preferences in charging and the diversification of the control action during charging for the exploitation of the vehicle to grid concept.

Optimal Planning and Routing in Medium Voltage PowerLine Communications Networks

This paper deals with the problem of deploying a PowerLine Communication (PLC) network over a medium voltage (MV) power grid. The PLC network is used to connect the end nodes (ENs) of the MV grid to the service provider by means of PLC network nodes enabled as access points. In particular, a network planning problem is faced wherein we require to define the PLC network topology by deciding which MV network nodes are to be enabled as access points. An optimization problem is then formulated, which minimizes the cost of enabling the access points and maximizes the reliability of PLC network paths in a multi-objective optimization fashion. This work also considers resiliency (i.e., it guarantees the PLC network connectivity even in case of link faults) and capacity constraints (i.e., it checks that there are enough resources to transmit the estimated amount of traffic over the PLC network paths). As a byproduct, the optimization algorithm also returns the optimal routing. Simulations based on realistic MV network topologies validate the proposed approach.

Validation of a QoS architecture for DVB-RCS satellite networks via the SATIP6 demonstration platform

Full integration of satellite technology in future terrestrial infrastructures requires support for high-quality broadband bi-directional communications. Research efforts in the field of satellite communications are currently oriented in the study of QoS-aware solutions for DVB-S and DVB-RCS which allow seamless deployment in the Internet. In this paper, the QoS architecture of the SATIP6 project, sponsored within the 5th EU Research Programme Framework, is presented, along with the implemented demonstrator and the obtained results. The QoS architecture is organized into two main modules, the Traffic Control and Access Control modules, whose aims are (i) to provide for differentiated service of conveyed IP flows and (ii) to achieve efficient utilization of uplink bandwidth, respectively. Experimental results obtained through the developed demonstration platform are reported and discussed to assess the effectiveness of the designed solution in terms of both service differentiation and efficient utilization of satellite resources.

Resilient planning of PowerLine Communications networks over Medium Voltage distribution grids

In this paper a network planning problem aiming to enable underground Medium Voltage (MV) power grids to resilient PowerLine Communications (PLCs) is faced. The PLC network is used to connect PLC End Nodes (ENs) located into the secondary substations to the energy management system of the utility by means of PLC network nodes enabled as Access Points. An optimization problem is formulated, aiming to optimally allocate the Access Points to the substations and the repeaters to the MV feeders. A multi-objective optimization approach is used, in order to keep in balance the needs of minimizing the cost of equipment allocation and maximizing the reliability of PLC network paths. Resiliency and capacity constraints are properly modeled, in order to guarantee the communications even under faulted link conditions. As a byproduct, the optimization algorithm also returns the optimal routing. Simulations performed on a realistic underground MV distribution grid validate the proposed approach.