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We propose a real-time message scheduling algorithm which is applied to schedule periodic real-time messages in IEEE 802.15.4 for LR-WPAN(Low Rate Wireless Personal Area Network). The standard allows GTSs (Guaranteed Time Slots) in the optional use of a superframe structure in a beacon-enabled network to be used to exchange real-time messages. To utilize(More)
—Industrial applications of wireless sensor networks require timeliness in exchanging messages among nodes. Although IEEE 802.15.4 provides a superframe structure for real-time communication, a real-time message-scheduling algorithm is still required to schedule a large number of real-time messages to meet their timing constraints. We propose a(More)
With low-power consumption, small code and data size, evolvability as design criteria, we develop an evolvable operating system (EOS) for wireless sensor network applications. The EOS provides memory space efficient thread management, collaborative thread communication model and network stack. It also supports power management of microcontroller and radio(More)
To prolong the network lifetime, we propose an energy efficient chain-based routing scheme and a distributed algorithm for constructing the routing chain based on the minimum cost tree. The chain construction algorithm calculates the transmission cost based on received signal strength. Therefore, it doesn't require global knowledge of nodes' location(More)
When deploying sensors in the field in order to collect useful information , one of the most important issues is how to prolong the lifetime of the network because of energy constraint of the sensors while guaranteeing that every point in the network is covered. In this paper, we propose the formulation of integer linear programming (ILP) model to find the(More)
Image transmission in biomedical wireless sensor networks often requires low complexity, low power consumption with soft real-time constraint. However, the full separation of source coding and channel coding usually comes with large delay and/or complexity. To address these requirements, we propose a new direct mapping of source sample to channel sample(More)
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