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The article presents an analysis of correlation-based clustering procedure in cooperative spectrum sensing. The motivation is to assess if it is more beneficial in terms of energy efficiency to group nodes according to the received signal-to-noise ratio (SNR) on the link between Primary User and node or according to the distance between nodes. To this end, a merged clustering measure is introduced...
IoT architectures heavily depend on wireless resource-constrained nodes that collect and transmit a plethora of information. The broadband wireless medium enables malicious nodes to perform a number of attacks. Cryptographic means along with trust-based schemes are often deployed to combat these attacks. We propose a centralised trust-based scheme where all nodes monitor their neighbors, and report...
A Medium Access Control (MAC) protocol for time-critical wireless applications called Enhanced Priority MAC (EPMAC) is proposed in this paper. The proposed scheme supports three traffic categories prioritizing emergency traffic over non critical one and beacons are emitted to announce that the channel will be occupied. EP-MAC is designed so that the highest priority traffic postpones lowest priority...
Cognitive radio (CR) is a prominent candidate to solve the spectrum scarcity problem faced by the proposed as well as existing wireless services. It exploits the opportunities, also called as spectrum holes, and created due to the underutilization of the licensed spectrum. Spectrum sensing plays the most important role to detect these spectrum holes. Individual CR sometimes faces problems in accurate...
We propose a relay subset selection method for two-hop Wireless Sensor Networks (WSNs) where the source-relay links are modeled as time-varying fading channels. Assuming perfect channel estimation at relays, the channel state is quantized to binary levels, called as Good and Bad states, and is modeled by a Gilbert-Elliott channel. The relays compress their quantized channel state information and transmit...
Accurate spectrum sensing is very important for cognitive radio systems. In the cooperative spectrum sensing, the unreliable nodes will result in deterioration of detection performance. This paper focuses on the spectrum sensing in the case of unreliable nodes and proposes a weighted reliability cooperative spectrum sensing algorithm. In the algorithm, the global fusion center only chooses the cognitive...
In this paper we propose Cosine Modulated Filter Bank (CMFB) for spectrum sensing with programmable granularity for Cognitive Radio (CR). The bandwidth efficiency of the detected spectral holes can be increased by varying the granularity of prototype filter depending on the spectrum to be sensed. Here we emphasize spectrum sensing can be done effectively by proper choice of prototype filter with specified...
Wireless Sensor Networks have been used extensively for environment data collection from dense as well as simple linear structure deployments. However, the need to collect data from all sensors in the network imposes constraints on internode distances. Critical issues related to optimal resource allocation still persist for even simplistic deployments like linear and hierarchical networks. In this...
In this paper, we consider a sequential binary hypothesis testing framework in wireless sensor networks. We study the effect of sensor censoring on network performance in terms of the average error probability and average number of observations required until a global decision is made. The detection process is mathematically modeled as a random walk process with two absorbing barriers. We resort to...
In this paper, we propose two energy efficient ordered transmission schemes with fusion rules for distributed detection in wireless sensor networks (WSNs). The fusion rule at the fusion center (FC) has been derived to take into account not only the reliability of local decision at sensors, but also channel gains from sensors to the FC. In the first scheme, the sensors' transmission order is based...
In this paper medical ICT scenarios are considered where a user/patient communicates to a base station with the help of one or more mobile devices in its close proximity. The system model assumes all the wireless devices cooperate in a mobile cloud. First of all, we identify medical ICT scenarios and select the most promising ones where the concept of mobile cloud can be readily exploited. Two cooperative...
Data gathering is a fundamental operation for various applications of wireless sensor networks (WSNs), where sensor nodes sense information and forward data to a sink node via multi-hop wireless communications. Typically, data in a WSN is relayed over a tree topology to the sink for effective data gathering. A number of tree-based data gathering schemes have been proposed in the literature, most of...
In this contribution, a parallel triple-layer wireless sensor network (WSN) is introduced to monitor a source event (SE) with M states. For the sake of facilitating low-complexity noncoherent fusion rules, in the considered WSN, frequency-hopping (FH) and M-ary frequency-shift keying (MFSK) modulation are used to transmit signals from local sensor nodes (LSNs) to fusion center (FC). Hence, the WSN...
This paper is focused on analyzing the effects of primary user (PU) signal arrival in the sensing interval on the local spectrum sensing performance. The probability for signal arrival at a sample in the sensing time is uniformly distributed. In this case, the performance degradation of the conventional energy detection (CED) method is analyzed. Furthermore, in order to enhance performance, an approach...
In this paper, we consider the problem of binary hypothesis testing for distributed detection in wireless sensor networks in which a transmission censoring scheme is employed. The sensor nodes transmit binary decisions to the fusion center (FC) for final decision making. Sensor nodes with unreliable observation samples censor transmission to FC. By having two thresholds at each sensor node, a sensor...
This paper presents a probabilistic transmission control technique for the distributed estimation in WSNs. The presented technique is based on a novel transmission control which is to minimize a mean squared error of estimation by increasing the packet transmission success probability of only sensors having the high observation SNR. In the presented method, the transmission of sensors is probabilistically...
We present the ε-outage capacity in the low signal-to-noise ratio (SNR) regime of an incremental relaying network. The network consists of one source, one destination, and two half-duplex relays. The one-bit feedback from the destination node is considered to be imperfect and is modeled as binary symmetric channel. The basic idea is that in each block only one terminal transmits depending on the feedback...
A simple cooperative diversity technique is applied to point-to-multipoint communication in wireless medium suffering from Rayleigh block fading. Such a concept is especially interesting if low-cost radios, which have no advanced capabilities for fading mitigation, are used. This paper analyzes the communication reliability in terms of outage and delivery ratio, and compares cooperative and non-cooperative...
In this paper, we investigate optimal fusion schemes for decentralized detection problems in which a network of wireless sensors provides relevant information about the state of nature to a fusion center. Upon independent reception of the signal, each sensor performs distributed binary detection and sends the decision as well as the reliability of the decision to the fusion center. The capacity region...
Underwater communication is a challenging topic due to its singular channel characteristics. Most protocols used in terrestrial wireless communication can not be directly applied in the underwater world. In this paper, we focus on the issue of energy efficient transmission in underwater sensor networks (UWSNs) and analyze this problem in a rigorous and theoretical way. We formalize an optimization...
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