Abstract Wireless body sensor networks (WBSNs) enable a broad range of applications for continuous and real‐time health monitoring and medical assistance. Programming WBSN applications is a complex task especially due to the limitation of resources of typical hardware platforms and to the lack of suitable software abstractions. In this paper, SPINE (signal processing in‐node environment), a domain‐specific framework for rapid prototyping of WBSN applications, which is lightweight and flexible enough to be easily customized to fit particular application‐specific needs, is presented. The architecture of SPINE has two main components: one implemented on the node coordinating the WBSN and one on the nodes with sensors. The former is based on a Java application, which allows to configure and manage the network and implements the classification functions that are too heavy to be implemented on the sensor nodes. The latter supports sensing, computing and data transmission operations through a set of libraries, protocols and utility functions that are currently implemented for TinyOS platforms. SPINE allows evaluating different architectural choices and deciding how to distribute signal processing and classification functions over the nodes of the network. Finally, this paper describes an activity monitoring application and presents the benefits of using the SPINE framework. Copyright © 2010 John Wiley & Sons, Ltd.

Body sensor networks are emerging as a promising platform for healthcare monitoring. These systems are composed of battery-operated embedded devices which process physiological data. The reduction in the power consumption is an important factor to increase the lifetime for such systems and to enhance their wearability through reducing the size of the battery. In this paper, we develop an energy-efficient communication scheme that uses buffers to reduce the number of transmissions among the sensor nodes constrained to limited hardware resources. A direct acyclic graph is used to model the information flow. We define a communication optimization problem and solve it using convex optimization techniques. We present results that support the efficiency of the proposed technique.

SPINE (signal processing in node environment) is a framework for the development of body sensor network (BSN) applications. It provides developers of signal processing algorithms with APIs and libraries of protocols, utilities and data processing functions. Hence, it offers application developers new abstractions that improve interoperability and allow to reduce development time. This paper presents the architecture and the capabilities of the SPINE framework, and shows its use in the development of a real-time activity monitoring system prototype.

This paper proposes a cross-layer optimization framework that provides efficient allocation of wireless network resources across multiple types of applications to maximize network capacity and user satisfaction. We define a novel optimization scheme based on the Mean Opinion Score (MOS) as the unifying metric. Our experiments, applied to scenarios where users simultaneously run three types of applications, such as realtime voice, video conferencing and file download, confirm that MOS-based optimization leads to significant improvement in terms of user perceived quality when compared to throughput-based optimization.

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.

We propose an application-driven multi-user resource allocation and frame scheduling concept for wireless video streaming. Our approach is based on joint optimization of the application layer, the data link layer and the physical layer. For this, key parameters from these three layers are abstracted. The abstracted parameters at the application layer describe the rate-distortion characteristics of the pre-encoded video streams. At the lower layers they describe the current transmission characteristics of all users. The outcome of the joint optimization leads to adaptive resource allocation at the lower layers and an adaptive decision on which frames to send on the application layer. We show that for our scenario the expected video quality at the client side can be described analytically which leads to low complexity joint optimization. The performance of our approach is demonstrated using a real-time testbed implementation.

Cross-layer design (CLD) is a new paradigm for network architecture that allows us to make better use of network resources by optimizing across the boundaries of traditional network layers. Previous work has shown that applying CLD to mobile multimedia communication systems may lead to significant performance improvements. In this paper we also consider the other side of the coin, i.e., the additional computation and communication overhead introduced by CLD. We evaluate the performance improvements and the cost of cross-layer optimization using a wireless multi-user video streaming example.

Platforms have become an important concept in the design of electronic systems. We present here the motivations behind the interest shown and the challenges that we have to face to make the Platform-based Design method a standard. As a generic term, platforms have meant different things to different people. The main challenges are to distill the essence of the method, to formalize it and to provide a framework to support its use in areas that go beyond the original domain of application.

Communication-based design represents a formal method approach to of system-on-a-chip design that considers communication between components as important as the computations they perform. “Our network-on-chip&rdqo ; approach partitions the communication into layers to maximize reuse and provide a programmer with an abstraction of the underlying communication framework. This layered approach is cast in the structure advocated by the OSI Reference network model and is demonstrated with a reconfigurable DSP example. The Metropolis methodology of deriving layers through a sequence of successive adaptation steps between incompatible behaviors refinement of communication is illustrated through the Intercom a design example. In another approach, MESCAL provides a designer with tools for a correct-by-construction protocol stack.

Communication protocols are essential components of wireless systems. Present methods for protocol design are heuristic in nature and are not suited for next generation wireless systems where time-to-market concerns require correct-the-first-time implementations. In this paper we present a new design methodology for wireless protocols based on the principle of orthogonalization of concerns. In particular, the methodology separates function and architecture design and emphasizes the use of formal models to ensure correctness and reduce design time. Protocols are described using co-design finite state machines (CFSMs), a model of computation that has been introduced to allow the efficient capture of both the control and the data processing parts of the specification. Furthermore, algorithms for automatic hardware and software synthesis from CFSMs are available. This allows a fast exploration of different HW/SW partitions and the analysis of tradeoffs involved. Intercom, a mobile wireless system supporting full-duplex voice communication among different users, is presented and the design of its protocols is described. The design methodology presented here will be used for the design of PicoRadio, a low-power and highly adaptive network of sensors.

Software synthesis from a concurrent functional specification is a key problem in the design of embedded systems.A concurrent specification is well-suited for medium-grained partitioning.However, in order to be implemented in software, concurrent tasks need to be scheduled on a shared resource (the processor).The choice of the scheduling policy mainly depends on the specification of the system.For pure dataflow specifications, it is possible to apply a fully static scheduling technique, while for algorithms containing data-dependent control structures, like the if-then-else or while-do constructs, the dynamic behaviour of the system cannot be completely predicted at compile time and some scheduling decisions are to be made at run-time.For such applications we propose a Quasi-static scheduling (QSS) algorithm that generates a schedule in which run-time decisions are made only for data-dependent control structures.We use Free Choice Petri Nets (FCPNs), as underlying model, and define quasi-static schedulability for FCPNs.The proposed algorithm is complete, in that it can solve QSS for any FCPN that is quasi-statically schedulable.Finally, we show how to synthesize from a quasi-static schedule a C code implementation that consists of a set of concurrent tasks.

We describe a technique for hardware-software co-simulation that is almost cycle-accurate, and does nor require the use of interprocess communication for a C language interface for the software components. Software is modeled by using behavioral VHDL constructs, annotated with timing information derived from basic block-level timing estimates. Hardware is also modeled in VHDL, and can be either pre-existing intellectual property or synthesized to RTL from a functional specification. Execution of the VHDL processes modeling software tasks is coordinated by a process emulating the target RTOS behavior. The effects of changing the hardware/software partition can be quickly estimated by changing a process parameter defining its target implementation and the processor on which it is running.