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Spectrum scarcity is one of the primary bottlenecks for the future wireless communication systems, for better spectrum utilization cognitive radio plays a vital role. Cognitive radio is a new paradigm of designing wireless communications systems which aims to enhance the utilization of the radio frequency (RF) spectrum for wireless communications. Available spectrum bands may vary with different cognitive...
The concept of backoff algorithm is used in self scheduled MAC protocol to enhance the number of successful cognitive users by reducing the collision during reservation of idle licensed channels. Hence the throughput of cognitive network is increased.
Wireless networks are very popular due to its peak nowadays, because the users need wireless connectivity regardless of their geographic position. There's an increasing threat of attacks on the Wireless sensor Network (WSN). Node replication attack is one in all the security threat within which the traffic is redirected to such a node that really doesn't exist within the network. It's an analogy to...
Wireless LAN 802.11 is one of the widely used specifications for wlan networks. 802.11 e has increased its utility and QoS by assigning priorities to different types of data packet. Method employed by 802.11e at its MAC layer specification determines the channel access mechanism, known as EDCF. The fixed approach of EDCF of increasing the CW size without taking in consideration channel condition results...
With the growing demand for wireless applications, there is an incalculable rise in bandwidth consumption that in turn leads to the spectrum scarcity. The conflict between spectrum underutilization and spectrum scarcity is solved by a well-known technology called Cognitive Radio (CR). The main aim of CR is to exploit unutilized spectrum of licensed users/Primary Users (PUs) and enable opportunistic...
In this work, a cooperative scenario of cognitive network is considered to maximize the energy efficiency and throughput while maintaining certain boundary conditions like, probability of detection threshold and total power budget allocation. After evaluation of the mathematical form, simulation is done on the basis of relay amplifying factor. Additionally, the optimal level of relay amplifying factor...
Wireless Sensor Networks are gaining more and more importance in present era. Recent Advances in WSN have extended the applicability of these to wide range of real time applications. In these applications, energy is one of the scarce resources. Hence, the main goal of any application using WSN is to spend less energy and extend the lifetime of the WSN. For any type of network communication, quality...
Spectrum channel is a limited resource in mobile wireless communication. In dramatic evolvement of communication, a resource sharing scenario of heterogeneous network is a challenging. The D2D system with synchronous transmission requires a medium access control (MAC) protocol, which provides sharing resource and maintains the protection level of the existed M2M system with asynchronous transmission...
SRAM is a key building block in systems-on-chip and usually limits their voltage scalability, due to the major impact of process/voltage/temperature (PVT) variations at low voltages [1]. Assist techniques to extend SRAM operating voltage range improve the bit cell read/write stability [1–5], but cannot mitigate variations in the internal sensing delay that is needed to develop the targeted bitline...
Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) adopted in IEEE 802.11 WLAN suffers from serious problems of hidden terminal and exposed terminal. This will get worse if the environment becomes highly dense. The rise of channel interference among stations (STA) and the deterioration of the total network throughput as the result of these terminal problems need to be mitigated. A possible...
In this paper the performance of a cognitive radio (CR)network is investigated under harvesting of energy from combined RF signal and ambient sources, i.e., non-RF signal. The CR harvests energy from ambient sources as well as from primary user (PU) signal depending on the sensing decision. The quality of service (QoS) of PU is protected in terms of collision probability. The performance has been...
Recently there have been numerous studies exploring the benefits of the coalition formation in a cognitive radio network and it has been shown that coalition formation tends to improve the performance of cognitive radios. In this paper, we use the concepts from matching theory to form coalitions among cognitive radio users for cooperative spectrum sensing under target detection probability constraint...
This paper focuses on the use of CoAP as a means of connecting clouds of sensors & smart devices via mobile devices with users. We present an alternative to the hierarchical view on fog-computing by enabling device clouds to interact in a P2P fashion with smart device/sensor clouds. Using the IoT protocol CoAP we expose smart device/sensors and resources in the mobile cloud in a uniform manner...
Cooperative spectrum sensing has a great impact to increase the performance for detecting the Primary User (PU) signal over single node sensing. Recent developments in multiple antenna techniques adjoin a new dimension in spectrum sensing. In this paper, we have proposed a multi-antenna based signal detection for multi bands considering cooperative approach with Rayleigh fading channel. In addition...
Protecting and hiding the transmission of information over wireless channels at the physical layer level is of great importance in several applications. An Ad-Hoc covert network (ACN) is a set of users that exchange information over a wireless channel with a low probability of being detected by an intercept receiver. The ACN achieves a low probability of detection by hiding its transmission within...
A cooperative cognitive radio (CR) network that accomplishes both spectrum sensing (SS) and sharing is considered in this work. System model is assumed to be a cognitive ad hoc network that consists of multiple secondary transmitter (ST) and receiver (SR) pairs sharing transmission over a spectrum with a primary network of single transmitter-receiver pair. Based on SS outcome, secondary users (SUs)...
Opportunistic spectrum access is a key technology for the development of novel applications with stringent QoS requirements on top of wireless sensor networks. However, the many challenges posed by opportunistic spectrum access itself are further exacerbated by the power constrained nature of wireless sensors and the QoS requirements of the applications to be supported. In this work we consider the...
In this paper, we propose a modified cooperative sensing scheme as documented by IEEE 802.22 standard to develop a spectrum agile simpler implementable cognitive radio network (CRN) by minimizing the probability of false alarm and maximizing the probability of detection to optimize the maximum achievable system throughput through the optimal decision fusion rule. In addition, we develop a dynamic...
In this paper, a novel context aware medium access control (MAC) scheme is proposed for multichannel buffer-aided cognitive networks. The proposed scheme allows management of the delay of the primary network (PN) and secondary network (SN) more efficiently by exploiting the packets' context. In the proposed multiple access policy, two different context aware approaches for packet prioritization are...
The ever-increasing demands of wireless traffic call for continuously growing the wireless network capacity or throughput. Carrier sensing threshold adaptation and transmission rate adaptation, two efficient mechanisms improving the capacity of ad hoc network, have attracted much attention in recent years. However, simply adopting either mechanism can hardly meet the expectation that optimizing the...
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