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Wireless sensor networks operating in 2.4 GHz ISM band are seriously affected by interference from coexisting radio systems such as IEEE 802.11× wireless local area networks. In this paper, we investigate the transmission performance of wireless sensor networks in the presence of co-channel interference. We first analyze the probability of transmission failure and data throughput associated with transmission...
This paper investigates an energy-efficient transmission scheme in cognitive radio networks, where primary users (PUs) may reoccupy the spectrum when secondary users (SUs) is transmitting data. We aim to maximize the energy efficiency by jointly optimizing the transmission power, the fusion rule threshold and the sensing/transmission durations. Firstly, it is derived that for a given fusion rule threshold,...
Constant monitoring of patient's health is essential to provide appropriate healthcare. With advances in electronic circuit miniaturization and micro-electromechanical systems (MEMS), wearable sensor nodes can be used to acquire physiological signals from patient's body and transmit them to a remote location which can be accessed by the doctors. Wireless Sensor Networks (WSNs) are becoming an integral...
With the rapid development of radio technology, the problem of spectrum scarcity becomes an important area of research in the wireless communications field. Cognitive Radio (CR) technology is introduced as a solution to allow secondary (unlicensed) users to utilize the available frequency bands that are unutilized by primary (licensed) users. This feature, offered to CR users, has shown great potential...
In Cognitive Radio network, the Secondary Users (SU) makes use of the spectrum of licensed primary user when they are unoccupied. Here we have studied and expressed the normalized throughput for both single secondary user and multiple secondary users coexisting under cooperative sensing technique. We have also incorporated the consequences due to imperfect sensing and analyzed the throughput under...
Dynamic spectrum access in the form of cognitive radio (CR) has gained traction in wireless sensor networks (WSN) because of a) scarcity caused by the proliferation of wireless devices and service and b) it provides spectrum efficient communication for the resource constrained WSNs. However, proper means have to be devised to satisfy the requirements of both WSNs and CRs and to enjoy the benefits...
This paper considers an ad hoc network with multiple transmitter-receiver pairs, in which all transmitters are capable of harvesting renewable energy from the environment and compete for the same channel by random access. To quantify the roles of both the energy state information (ESI) and the channel state information (CSI), a distributed opportunistic scheduling (DOS) framework with a save-then-transmit...
Multicast routing is a fundamental issue in wireless networks and related routing strategies should select the lowest number of parallel conflicting transmissions. However, current works on this problem accounts only for conflicts occurring within the transmission ranges of the nodes. Particularly, no work is interested in studying conflicting transmissions while using multi-rate concurrent multicast...
VANETs inherit a conservative channel access control mechanism from IEEE 802.11 standard to mitigate the hidden terminal problem on the service channels, i.e., once a service channel is reserved by a node, all its neighbors in 2-hop range are prohibited from initiating the transmission simultaneously. To improve the channel utilization and increase the network capacity, we propose an optimistic distributed...
Diversified applications of wireless sensor networks demand reliable data transmission, which generally experiences limited performance owing to the inherent resource constraints of sensor nodes. Estimated round trip time is one of the prominent aspects of reliable transmissions that possesses a potential to enhance the performance sustaining the resource constraints. Therefore, we have already proposed...
Spatial diversity for wireless transmission requires more than one antenna at the transmitter. However, mobile devices are usually limited by size, so installation of multiple antennas increases the hardware complexity significantly. Due to the omnidirectional nature of wireless signal, a data transmission between a source node and a destination node can be overheard by many other neighbor nodes....
In recent years, with the rapid growth in wireless communication applications, issues in energy consumption has been increasingly critical, especially in cognitive radio (CR) systems with the exclusive functionality of spectrum sensing. In this paper, we consider a self-powered cognitive radio system, in which the SU has no fixed power supplies (e.g. batteries) and is powered by an energy harvester...
To solve the problems of control channel bottleneck and communication delay in multi-radio wireless sensor networks, this paper designs an asynchronous MAC protocol named UMD2-MAC in which a union mechanism of prime channel hopping(PCH for short) and control-channel reservation is used. The channel hopping makes sure that the average delay of selecting the same channel is small while the reservation...
Mobile devices with multihoming capabilities have gained large-scale popularity in recent years. However, these network interfaces cannot be fully utilized in most applications. In this paper, we propose a concurrent transmission method that allows mobile applications to fully use multiple interfaces simultaneously in a transparent manner. Using this method, applications benefit from network enhancement,...
We consider data transmission with an energy harvesting transmitter with non-negligible processing circuitry power and a hybrid energy storage unit composed of an ideal super-capacitor (SC) and an inefficient battery. The SC has finite space for energy storage while the battery has unlimited space. The transmitter stores the harvested energy either in the SC or in the battery and the energy is drained...
RFID wireless sensor networks may produce a large number of data in some applications, congestion should be taken into account in some wireless sensor networks applications. A routing protocol based on Stackelberg game is proposed to reduce network congestion in this paper. It puts forward the network Stackelberg model and proves the existence of Nash equilibrium. The transmission rate is adjusted...
The paper introduces proactive integrated handoff management (IHM) scheme in cognitive radio mobile ad hoc networks (CR-MANETs) through an established route. This scheme considers the primary user (PU) activity, secondary user (SU) mobility and channel heterogeneity in the spectrum handoff decision. To reduce the handoff delay, handoff thresholds are used. When the spectrum handoff cannot be done...
Network protocol performance is closely related to knowledge about the network state. However, acquiring such knowledge expends network bandwidth resource. Thus a trade off exists between the amount of bandwidth resource expended in acquiring knowledge about network state, and the improved protocol performance due to such knowledge. Previous work used rate distortion theory to calculate the minimum...
In this paper, a new adaptive cooperative spectrum sensing scheme using random access is proposed in a cognitive radio network. Cooperative spectrum sensing improves spectrum sensing performance considerably. In typical cooperative spectrum sensing situations, spectrum sensing data of several secondary users are collected before sensing decision. Yet how to collect the sensing data is not an easy...
There have been significant levels of research into how to use technology to teach programming principles. However, there has been less research to show how technology can be used to help teach network fundamentals in a creative way. Instead, simulation has been widely adopted as the main software tool when teaching networking concepts. In this paper we examine a more applied approach to help students...
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