Localization (a.k.a. locationing) is a central concern for ubiquitous self-configuring sensor networks. In this paper the implementation of a distributed, least-squares-based localization algorithm is presented. Low power and energy dissipation are key requirements for sensor networks. As part of the sensor network, the localization system must also conform to these requirements. An ultra-low-power and dedicated hardware implementation of the localization system is therefore presented. The cost of fixed-point implementation is also investigated. The design is implemented in a 0.13 /spl mu/ CMOS process. It dissipates 1.7 mW of active power and 0.122 J/op of active energy with a silicon area of 0.55 mm/sup 2/. The mean calculated location error due to fixed-point implementation is shown to be 6%.

A low power wireless intercom system is designed and implemented. Two fully-operational ASICs, integrating custom and commercial IP, implement the entire digital portion of the protocol stack. Combined, the chips consume 13 mW on average when three nodes are connected to the network. A high-level design methodology was used to define the protocol stack and communication algorithms, select architectures, and minimize energy.

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.

One of the most compelling challenges of the next decade is the "last-meter" problem, extending the expanding data network into end-user data-collection and monitoring devices. PicoRadio supports the assembly of an ad hoc wireless network of self-contained mesoscale, low-cost, low-energy sensor and monitor nodes. While technology advances have made it conceivable to deploy wireless networks of heterogeneous nodes, the design of a low-power, low-cost, adaptive node in a reduced time to market is still a challenge. We present a design methodology for PicoRadio Networks, from system conception and optimization to silicon platform implementation. For each phase of the design, we demonstrate the applicability of our methodology through promising experimental results.