The throughput performance of secondary users sharing radio spectrum with a licensed primary user is analyzed in this work. An asynchronous transmission, sensing and backoff protocol is proposed for the secondary user and modeled as a six state Markov process. The model parameters are derived as a function of the duty cycle and average duration that the channel is unoccupied by the primary user...

We consider the problem of multihop broadcast over adaptively duty-cycled wireless sensor networks (WSNs) where neighborhood nodes are not simultaneously awake. We present Hybrid-cast, an asynchronous and multihop broadcasting protocol, which can be applied to low duty-cycling or quorum-based duty-cycling schedule where nodes send out a beacon message at the beginning of wakeup slots. Hybridcas...

In this paper, we propose TB-MAC (Threshold-Based MAC), which has been designed to consider various network traffic conditions while providing energy efficiency in a wireless sensor networks. Existing MAC protocols for sensor networks attempt to solve the energy consumption problem caused by idle listening using an active/sleep duty cycle. Since there are various traffic conditions, however, th...

We consider periodic sensor scheduling in this paper. A system is observed by two sensors. The two sensors communicate their datawith a remote state estimator via a bandwidth-limited networkwhich allows only one sensor to send its data at each time. We derive the optimal duty cycle pair and a corresponding sensor data schedule to minimize the trace of the average estimation error covariance. Si...

Starting in 1965, M. Hildebrand developed criteria to classify quadrupedal gaits by two numbers, the lag of footfall of ipsilateral feet and the duty factor. He compared over 150 different species of animals using this method [1, 2]. The gaits were categorized into two groups: symmetrical gaits and asymmetrical gaits, and analyzed separately. This method allows a graphical classification of gai...

Wireless sensor networks (WSNs) are increasingly used in environmental monitoring applications. They are designed to operate for several months by featuring low activity cycles, in order to save energy. In this paper, we propose a MAC protocol for such WSNs with duty-cycles of 1%. Initially, nodes are activated randomly and independently, then they use the knowledge of previous successful frame...

The IEEE 802.15.4 standard provides the widely accepted solution for low-cost and low-power wireless communications. Despite its design support for low duty-cycle operation, the fixed superframe size in Beacon-enabled mode limits its capabilities due to two contrasting goals; energy efficiency and higher data throughput. In this paper, we propose an enhancement of IEEE 802.15.4 Beacon-enabled m...

A great amount of work addressed methods for predicting the battery lifetime in wireless sensor systems. In spite of these efforts, the reported experimental results demonstrate that the duty-cycle current average method, which is widely used to this aim, fails in accurately estimating the battery life time of most of the presented wireless sensor system applications. The aim of this paper is t...

Channel uncertainty limits the achievable data rates of power constrained wide band systems, where the data rate penalty depends on the number of channel parameters the receiver has to estimate per unit time. Duty cycle transmission reduces the channel uncertainty because the receiver has to estimate the channel only when transmission takes place. The transmission period should equal the cohere...

Behavioural experiments with crickets show that female crickets respond only to the male calling songs with a syllable rate within a specific interval, further it has been discovered that their response is independent of the duty-cycle of the song. Previously a neural control model was posed, which was able to explain how the selectivity of songs with syllable rates within a certain bandwidth c...