A decade ago, riding the devel¬opments in integrated circuit technology and the promises of Moore’s law, the concept of smart dust surfaced. Micro¬scopic devices with sensing, computing, and communication capabilities would be deployed in large numbers in the envi¬ronment to form a bridge between the digital and physi¬cal worlds.1 Along the way, however, major hurdles have blocked this goal. Node energy wasn’t sufficient to communi¬cate across large distances; short-range communications suffered from collisions and retransmissions; and routing algorithms depleted the power of the last tier before the fusion center in continuous moni¬toring applications.2 Moreover, theory showed that matters would only get worse in terms of transport capacity as the number of nodes in the network increased.3 In the end, most critical issues in designing smart dust networks remain open. We’re still waiting for Moore’s law to support the increased algorithm complexity needed to overcome these problems; we seek new battery technologies and energy-efficient systems to prevent nodes from dying out; or we shift our focus toward event-tracking applica¬tions with simpler traffic patterns. The bridge between the digital and physical worlds is only halfway built.
Despite these problems, continuous monitor¬ing wireless sensor networks (WSNs) are still considered the most effective means to har¬vest information from our physical environ¬ment. Moreover, a new concept—cooperative beam forming—promises to eliminate multi¬hop communications and its problems.4–6 The main idea behind cooperative beam forming suggests that if numerous N nodes, randomly placed in an area, share the same data, they can be configured to act as a random antenna array and produce a directional beam toward a desired direction.5 The overall transmission power will in this case be N times greater than that of a single node. Therefore, when nodes cooperate, they can support transmissions over large distances, enabling direct access to a distant fusion center without burdening the network with relaying tasks. However, the concept works only when all nodes transmit the same data and can maintain accurate syn¬chronization. To satisfy these conditions, all nodes in the beam-forming network will have to share information


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