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In this paper, secure communication for RF-powered cognitive networks has been investigated in which the secondary source (SS) transmits confidential information to the destination (SD) using the harvested energy form primary transmitter (PT) in the presence of a passive eavesdropper (SE). Note that the transmission power at the SS is subject to two important constraint: 1) the maximum transmission...
Interference is known to cause the performance degradation of the wireless network. To solve the interference problem, cooperative transmission scheme such as interference alignment (IA) is required. Channel state information (CSI) among IA participation nodes should be essentially obtained to implement IA. By implementing the IA prototype with obtaining the real environment CSI, we can check the...
In this paper, we propose an anti-interference cooperative spectrum sharing strategy based on fairness secondary users selection where the secondary system can gain spectrum access to the primary system. Specifically, secondary user STb and STq are selected to transmit the primary and secondary signal by using different bandwidth in the second transmission slot which occupies a part of the whole transmission...
In this paper, a cooperative spectrum sharing protocol with quality-of-service (QoS) support for both of the primary and secondary systems is proposed. Specifically, the secondary system gains primary spectrum access by allocating a fraction of its power to forward the primary signal helping the primary system achieve the target rate, and meanwhile exploits the remaining power to transmit its own...
There are large amounts of interference happening to GEO satellites which cause great harm to the communication systems. GEO-location becomes a very important means to eliminate the interference in satellite monitoring work. But the uncertainty makes the suspicious area quiet large and the target hard to be found. We purposed an image recognition algorithm applied in satellite interference transmitter...
In this paper we implement a turbo based Overlay Cognitive radio Z-channel with Trellis shaping, where the primary and cognitive users transmits and receives concurrently, utilizing the same spectrum. We ensure that bit error rate (BER) performance of the Primary does not degrade even in the presence of cognitive user. We derive bit error rate BER curves for both users, and show significant improvement...
Broadcasting is an important operation in wireless networks, as well as in cognitive radio (CR) networks. The operation of most network protocols in ad hoc networks depends on broadcasting control information among nodes. In traditional ad hoc networks, due to uniform channel availability, broadcasting is easily implemented as all nodes can be tuned to a single common channel. However, broadcast in...
In this work, we consider an underlay cognitive radio networks where the secondary transmitter transmits signal with power based on sensing result of the signal power transmitted by the primary transmitter. To improve the signal quality of the secondary transmission, we proposed an recursive algorithm to alternatively optimize multi-level power allocation and quantization regions of the sensing result...
All users in Cognitive radio networks (CRN) try to occupy the vacant channels sharing with the primary users and other users in CRN under limited channel utilization. Each selfish user can independently choose his strategy to maximize his own payoff at the Nash equilibrium (NE) state. In this work, we analyze the channel allocation problem of multiple CR users in the presence of interference of Primary...
In this paper, we consider beamforming design for an underlay cognitive radio multiple-input single-output broadcast channel, where a pair of secondary users coexists with multiple primary receivers. There exist multiple malicious eavesdroppers who attempt to overhear the confidential messages from the secondary system. When the channel state information of the eavesdroppers can only be obtained in...
In this paper, we analyze the secrecy performance of multi-antenna cognitive wiretap network, where the secondary transmitter (Alice) communicates with the secondary receiver (Bob) in the presence of an eavesdropper (Eve). Specifically, we investigate the cases of maximal- ratio combining (MRC) with half-duplex (HD) and selection combining/Zero forcing beamforming (SC/ZFB) scheme with full-duplex...
To maintain tractability, interference field is often modeled as a homogeneous Poisson Point Process (PPP) in the analysis of wireless networks. While it provides meaningful firstorder results, it falls short in modeling the effect of interference management techniques, which typically introduce some form of spatial interaction among transmitters. In some applications, such as cognitive radio and...
In this paper, a performance analysis for cognitive radio networks (CRNs) under the outage probability constraint of the primary user and peak transmit power constraint of the secondary user is conducted. Given an automatic repeat request protocol, analytical expressions for the packet delay and throughput of the CRN are derived. Most importantly, these expressions can be used to understand the quality...
In this paper, we study the problem of resource allocation for an opportunistic spectrum-sharing channel under the assumption of statistical channel state information (CSI). More specifically, we assume that statistical CSI of the channels between both primary and secondary transmitters and the primary receiver is available at the secondary transmitter. We investigate the achievable rate maximization...
Studies carried out across the world have revealed underutilization of the UHF/VHF TV bands. Standards and required equipment to opportunistically harness these TV whitespaces have evolved in recent past. Progress is also being made in India with respect to the study of the TV band spectral occupancies and it potential usage. One of the most attractive uses of TV whitespace in India would be for last...
The rapid growth of wireless systems have led to increased demand of the spectrum in the wireless services. The dynamic allocation of the wireless channel is one of the viable options which offer a great deal of scope to overcome several challenges. Cognitive Radio (CR) technology offers likelihood of dynamic allocation of spectrum by enabling unlicensed users to use the licensed spectrum in a proficient...
The performance of a cognitive radio based Transmitter Pre-processing (TP) assisted Multi-Carrier (MC)-Code Division Multiple Access (CDMA) system over correlated frequency-selective channels for downlink communication is presented in this paper. The Singular Value Decomposition (SVD) helps us understand the need for TP. Channel State Information (CSI) is collected via feedback channels and this SVD...
In this paper, we consider a downlink Multiple-Input-Multiple-Output (MIMO) cognitive radio network whereSecondary Users (SUs) are allowed to transmit concurrently withPrimary users (PUs) under an interference limit. We assume thatthe Channel State Information (CSI) required at the SecondaryBase Station (SBS) is available through a limited feedbackchannel and that it can be disturbed by estimation...
The hidden terminal problem, exposed terminal problem and co-channel interference problem are three main factors that limit the performance of wireless mesh networks. The network throughput can be increased by using multi-radio multichannel technology through using different channels to avoid the collisions. In this paper, we provide a channel assignment scheme considering interference, hidden/exposed...
The study proposes a new scheme for MIMO-based ad hoc networks. This is accomplished, while using the Interference Driving Technique (IDT) over Nakagami-m fading channels with perfect channel state information at both the transmitter and receiver. The use of this technique is proposed to decrease the impact of all the unwanted interferences, routinely caused by the overlap of the defined radio transmission...
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