Alvise Bonivento

System Level Design for Clustered Wireless Sensor Networks

We present a system level design methodology for clustered wireless sensor networks based on a semi-random communication protocol called SERAN, a mathematical model that allows to optimize the protocol parameters, and a network initialization and maintenance procedure. SERAN is a two-layer (routing and MAC) protocol. At both layers, SERAN combines a randomized and a deterministic approach. While the randomized component provides robustness over unreliable channels, the deterministic component avoids an explosion of packet collisions and allows our protocol to scale with network size. The combined result is a high reliability and major energy savings when dense clusters are used. Our solution is based on a mathematical model that characterizes performance accurately without resorting to extensive simulations. Thanks to this model, the user needs only to specify the application requirements in terms of end-to-end packet delay and packet loss probability, select the intended hardware platform, and the protocol parameters are set automatically to satisfy latency requirements and optimize for energy consumption.

System level design paradigms: Platform-based design and communication synthesis

Embedded system level design must be based on paradigms that make formal foundations and unification a cornerstone of their construction. Platform-Based designs and communication synthesis are important components of the paradigm shift we advocate.Communication synthesis is a fundamental productivity tool in a design methodology where reuse is enforced. Communication design in a reuse methodology starts with a set of functional requirements and constraints on the interaction among components and then proceeds to build protocols, topology, and physical implementations that satisfy requirements and constraints while optimizing appropriate measures of efficiency of the implementation. Maximum efficiency can be reached when the communication specifications are entered at high levels of abstraction and the design process optimizes the implementation from this specification. Unfortunately, this process is very difficult if it is not cast in a rigorous framework. Platform-Based design helps define a successive refinement process where each step can be carried out automatically and optimized appropriately. We present two cases, an on-chip and a wireless sensor network design, where the resulting methodology gave encouraging results.

Platform-Based Design of Wireless Sensor Networks for Industrial Applications

We present a methodology, an environment and supporting tools to map an application on a wireless sensor network (WSN). While the method is quite general, we use extensively an example in the domain of industrial control as it is one of the most promising application of WSN and yet it is largely untouched by it. Our design flow starts from a high level description of the control algorithm and a set of candidate hardware platforms and automatically derives an implementation that satisfies system requirements while optimizing for power consumption. To manage the heterogeneity and complexity inherent in this rather complete design flow, we identify three abstraction layers and introduce the tools to transition between different layers and obtain the final solution. We present a case study of a control application for manufacturing plants that shows how the methodology covers all the aspects of the design process, from conceptual description to implementation

Breath: A Self-Adapting Protocol for Wireless Sensor Networks in Control and Automation

The novel cross-layer protocol Breath for wireless sensor networks is designed, implemented, and experimentally evaluated. The Breath protocol is based on randomized routing, MAC and duty-cycling, which allow it to minimize the energy consumption of the network while ensuring a desired packet delivery end-to-end reliability and delay. The system model includes a set of source nodes that transmit packets via multi-hop communication to the destination. A constrained optimization problem, for which the objective function is the network energy consumption and the constraints are the packet latency and reliability, is posed and solved. It is shown that the communication layers can be jointly optimized for energy efficiency. The optimal working point of the network is achieved with a simple algorithm, which adapts to traffic variations with negligible overhead. The protocol was implemented on a test-bed with off-the-shelf wireless sensor nodes. It is compared with a standard IEEE 802.15.4 solution. Experimental results show that Breath meets the latency and reliability requirements, and that it exhibits a good distribution of the working load, thus ensuring a long lifetime of the network.

SERAN: a semi random protocol solution for clustered wireless sensor networks

SERAN is a two-layer (routing and MAC) protocol for wireless sensor networks in manufacturing plants. At both layers, SERAN combines a randomized and a deterministic approach. While the randomized component provides robustness over unreliable channels, the deterministic component avoids an explosion of packet collisions and allows our protocol to scale with network size. Our solution is based on a mathematical model that characterizes performance accurately without extensive simulations. SERAN is robust against node failures and clock drifts, supports data aggregation algorithms and is easily implementable in any of the existing hardware platforms. Although SERAN was designed for manufacturing plants applications, it can be used in any type of clustered topology. We consider a representative case study and we present simulation results to show SERAN efficiency

Randomized protocol stack for ubiquitous networks in indoor environment

We present a novel protocol architecture for ubiq- uitous networks. Our solution is based on a randomized routing, MAC and duty cycling protocols that allow for performance and reliability leveraging node density. We show how the three layers can be jointly optimized for energy efficiency and we present a completely distributed algorithm that allows for the network to reach the optimal working point and adapt to traffic variations with negligible overhead. Finally, we present a set of simulation results that support our mathematical model.

Rialto: a bridge between description and implementation of control algorithms for wireless sensor networks

Rialto is a design framework that allows separating the description of a control application for wireless sensor networks from its physical network implementation. The methodology supported by Rialto consists of two steps: An application is described in a Rialto Model in terms of logical components queries and commands. The description is translated into an internal format called RialtoNet that is used to explore all the possible sequence of queries and commands that the application may lead to. The RialtoNet is executed and a set of constraints on the communication and sensing infrastructure is generated.The semantics of RialtoNet is based on a MoC that takes inspiration from Kahn Process Networks, but blocking rules are conveniently modified to exploit the domain specificity.Our approach offers a clear interface to the application designer as Rialto automatically bridges the gap between application and implementation. Hence, Rialto facilitates the adoption of wireless sensor networks technology in application domains, such as industrial control, where the application designer is not a communication engineer.

E2RINA: an Energy Efficient and Reliable In-Network Aggregation for Clustered Wireless Sensor Networks

The paper presents E2RINA, an aggregation algorithm for wireless sensor network applications characterized by clustered topologies, such as building automation and manufacturing plants. Thank to an efficient use of the wireless channel, E2RINA offers the robustness of the gossip-based algorithms and, at the same time, the energy performance of the faster cluster head-based algorithms. A mathematical model to predict the performance of the algorithm with respect to the free variables without the need of extensive simulations was also developed. The model was validated and the robustness of E2RINA by running a simulation model of a test case consisting of a cluster of MICA nodes.

Cooperative Diversity with Disconnection Constraints and Sleep Discipline for Power Control in Wireless Sensor Networks

We derive a power control policy for a group of sensor nodes that are monitoring a real-time application sensitive to disconnections (outages) of the communication. Specifically, we suggest that the sensor nodes perform cooperative diversity while running a sleep discipline. After the description of a detailed model of the wireless links, we propose a power minimization algorithm with a constraint expressed in terms of outage probability. Suboptimal solutions are also discussed. Numerical examples are provided for various number of nodes, wireless scenarios and nodes activities. It is argued that nodes with reduced activity show better performance

Modeling and early performance estimation for network processor applications

The design of modern embedded systems has to cope with quite challenging requirements in terms of flexibility, performance, and domain space exploration. To this purpose, we present a general methodology joining the principles of Platform Based Design and Model Driven Engineering. The former was especially conceived for embedded systems design, the latter focuses on models as the primary design artifacts. From their combination, we can to introduce a methodology for the design of Network Processor Applications. Starting from models described using the UML notation, we provide an early estimation of performance related parameters and compare in advance possible alternative implementations. In particular, the system behavior is specified by a collection of Sequence Diagrams describing the various usage scenarios, merged into an internal representation called Message Sequence Net. To prove the effectiveness of the proposed methodology, a case study on the design of an SCTP client is presented.