Infrastructure for Testing Nodes of a Wireless Sensor Network

Infrastructure for Testing Nodes of a Wireless Sensor Network

Bojan Mihajlovic (McGill University, Canada), Željko Žilic (McGill University, Canada) and Katarzyna Radecka (McGill University, Canada)
DOI: 10.4018/978-1-61520-701-5.ch005


Maintaining reliable networks of low cost, low energy wireless sensor network (WSN) nodes is a major concern. One way to maintain a reliable network is to perform in-field testing on nodes throughout their lifetimes, identifying failing nodes so that they can be repaired or replaced. This chapter explores the requirements for a wireless test access mechanism, and introduces a method for remote execution of software-based self-test (SBST) programs. In an effort to minimize overall test energy consumption, an SBST method is derived that takes the least amount of microcontroller cycles, and is compatible with system-level optimizations such as concurrent test execution. To further reduce test energy, compression algorithms compatible with WSN nodes are explored for use on test programs. The efficacy of all proposed methods is evaluated experimentally, using current measurement circuitry applied to a WSN node.
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Energy Efficiency

Since nodes are power-sensitive devices whose power sources are often on-board batteries, network quality can suffer if some or all nodes exhaust their energy reserves prematurely. Any overhead energy consumption must be minimized, such as the running of self-test programs. To do this, several energy-saving techniques are introduced which can reduce test energy consumption and test time:

Key Terms in this Chapter

Built-in self-test (BIST): A hardware module that generates test vectors, applies them to testable components, and constructs a test signature from the aggregated results.

Perceived availability (of a network): The probability that a network is functioning correctly over a period of time, as seen by a user of that network.

Rice coding: A form of static coding that allows for a degree of probability estimation to accommodate different source symbol probability densities.

Packet error rate (PER): The proportion of packets that have been received over a wireless link containing one of more errors.

Software-based self-test (SBST) program: Software created to test the components of the microcontroller is it executing on, and/or attached peripherals.

Automatic test pattern generation (ATPG): An algorithm by which test vectors are automatically generated from a design specification.

Energy-sensitive factors: the parameters of instructions that a microcontroller executes which affect its total energy consumption.

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