Energy-efficient design has become increasingly important to battery-powered wireless devices. In this paper, we focus on the energy efficiency of a cognitive radio network, in which secondary user senses channels licensed some primary users sequentially before it decides transmit. Energy is consumed both channel sensing and transmission processes. The energy-efficient calls for careful sensing-access strategies order, with strategy specifying when stop start transmission, access power level...

Intelligent reflecting surfaces (IRSs) are envisioned to provide reconfigurable wireless environments for future communication networks. In this paper, both downlink and uplink IRS-aided non-orthogonal multiple access (NOMA) orthogonal (OMA) networks studied, in which an IRS is deployed enhance the coverage by assisting a cell-edge user device (UD) communicate with base station (BS). To characterize system performance, new channel statistics of BS-IRS-UD link Nakagami- <inline-formula...

In this paper, we address the physical-layer security issue of a secondary user (SU) in spectrum-sharing cognitive radio network (CRN) from an information-theoretic perspective. Specially, consider secure multiple-input single-output (MISO) channel, where multi-antenna SU transmitter (SU-Tx) sends confidential information to legitimate receiver (SU-Rx) presence eavesdropper and on licensed band primary (PU). The secrecy capacity channel is characterized, which quasiconvex optimization...

In this paper, we address the issue of optimal transmitter design to achieve physical layer security for a multiple-input single-output (MISO) cognitive radio network (CRN), in which secondary user (SU-Tx) sends confidential information SU receiver (SU-Rx) on same frequency band with primary (PU) presence an eavesdropper (ED-Rx). It is assumed that all channel state (CSI) secondary, and channels not perfectly known at SU-Tx. The design, under restriction Gaussian signaling without...

The pilot spoofing attack is one kind of active eavesdropping conducted by a malicious user during the channel estimation phase legitimate transmission. In this attack, an intelligent adversary spoofs transmitter on state information (CSI) sending identical signal as receiver, in order to obtain larger rate data transmission phase. could also drastically weaken strength received at receiver if utilizes large enough power. Motivated serious problems cause, we propose efficient detector, named...

In this paper, we consider a joint design of energy-efficient sensing and transmission durations for cognitive radio (CR) system in which the primary user (PU) is protected. The problem formulated as function two variables, are durations, subject to interference PU. optimal solutions analyzed sub-optimal algorithm that maximizes energy efficiency CR presented. performance proposed also evaluated.

In this paper, physical layer security in multi-antenna small-cell networks is investigated, where the base stations (BSs), cellular users, and eavesdroppers are all randomly distributed according to three independent Poisson point processes. To improve secrecy performance, artificial noise (AN) aided transmission adopted at each BS. Based on stochastic geometry, we first derive closed-form expressions of connection outage probabilities, then comprehensively analyze impact different...

In this paper, non-orthogonal multiple access (NOMA) networks assisted by intelligent reflecting surfaces (IRSs) with discrete phase shifts are investigated, in which each user device (UD) is served an IRS to improve the quality of received signal. Two scenarios considered according whether there a direct link between base station (BS) and UD, outage performance analyzed for them. Specifically, asymptotic expressions upper lower bounds probability high signal-to-noise ratio (SNR) regime...

In this paper, we consider a wideband cognitive radio network (CRN) which can simultaneously sense multiple narrowband channels and thus aggregate the perceived available for transmission. We study problem of designing optimal spectrum sensing time power allocation schemes so as to maximize average achievable throughput CRN subject constraints probability detection total transmit power. The strategies are developed under two different constraints, namely, instantaneous constraint constraint....

The pilot spoofing attack is one kind of active eavesdropping activities conducted by a malicious user during the channel training phase. By transmitting identical (training) signals as those legal users, such an able to manipulate estimation outcome, which may result in larger rate for adversary but smaller legitimate receiver. With intention detecting and minimizing its damages, we design two-way training-based scheme. effective detector exploits intrusive component created adversary,...

In this paper, the security aspect of an amplify-and-forward relaying network with untrusted relay nodes is considered. The can help to forward received signal and they may also try decode such information, which be regarded as potential eavesdroppers (Eves). To deal a challenging issue, successive scheme adopted, where multi-antenna source transmits two selected alternately, conventional detrimental inter-relay interference used jam without external helpers. Considering different complexity...

In this letter, the issue of security for device-to-device (D2D) underlaying cellular networks is considered. The communication overheard by randomly distributed eavesdroppers. By sharing spectrum between D2D users and users, interference generated used as a source jamming to confuse We first derive connection probability links secrecy outage link based on stochastic geometry tools. then propose joint guard zone threshold-based access control scheme maximize achievable throughput. Moreover,...

In this letter, a generalized multi-relay selection scheme is proposed to improve the security in cooperative relay network. Assuming that only statistical channel state information of eavesdropper available at transmitter, semiclosed-form expression secrecy outage probability (SOP) derived. Based on this, both power allocation factor and number nodes are jointly optimized minimize SOP. Simulation results show outperforms conventional single-relay without increasing overhead.

We consider an energy-harvesting cognitive radio (CR) system coexisting with unslotted primary user (PU) system. The secondary (SU) either harvests energy from the PU transmissions or transmits when is sensed to be idle. In this paper, we optimize sensing intervals balance between harvesting and spectrum access, considering traffic statistics that affects both arrival consumption in addition opportunistic access. propose use different if SU decides transmit harvest energy. transmission...

In this paper, the secure transmission strategy for a multi-input-single-output multi-eavesdropper system with coexistence of user (Bob) and normal (NU) is investigated. The NU Bob require data transmissions, respectively, thus, stream can be exploited to confuse eavesdroppers. To guarantee security Bob, artificial noise (AN) also deliberately injected into null space NU. power allocation among NU, AN, as well wiretap code rates, jointly optimized maximize effective secrecy throughput (EST),...

In this paper, we investigate physical layer security in a two-tier heterogeneous network with sub-6 GHz massive multi-input multi-output (MIMO) macro cells and millimeter wave (mmWave) small cells. By considering pilot attacks from the eavesdroppers, analyze coverage secrecy performance using stochastic geometry. For tier, show that increasing number of BS antennas is more effective than density improving performance, whereas densifying for enhancement. mmWave first derive success...

This letter presents the bit error rate (BER) performance analysis for an uncoded binary phase-shift keying (BPSK) system in two-wave with diffused power (TWDP) fading channels. Simulation results of receiver performance, or without maximal-ratio combining (MRC), are also presented. These studies quantitatively reveal that TWDP can produce a link worse than Rayleigh when two direct waves equal strength and have combined /spl ges/ 6 dB higher power. point to using rather as worst case...

In this paper, we study the sensing-throughput tradeoff problem for a multiple-channel cognitive radio (CR) network. particular, using metric, investigate design of optimal spectrum sensing time and power allocation schemes so as to maximize aggregate ergodic throughput network guarantee quality service (QoS) primary users (PUs) without exceeding limit secondary transmitter. The strategies are developed under average constraint. Finally, numerical results show that, CR with 3 channels, whose...

A decentralized channel access strategy is proposed for a multichannel low-power cognitive radio (CR) system. CRs are equipped with rechargeable batteries to harvest radio-frequency (RF) energy from the primary user (PU) transmission. At any time, secondary users (SUs) can exploit either spatiotemporal spectrum opportunities transmission or PU active periods RF harvesting. An optimal channel-selection probability vector obtained achieve maximum SU throughput by finding sufficient...

The bit-error rate (BER) analysis for BPSK pre-detection maximal ratio combining (MRC) systems in two-wave with diffuse power (TWDP) fading is presented. In TWDP fading, the received signal composed of two specular components addition to signal. shows that BER MRC system given by weighted sum BERs a number Rician fading. methodology used verified through simulation.

We propose an efficient successive relaying (SR) transmission protocol for multiple-relay cooperative systems under the half-duplex constraint. In this protocol, process of relay selection is conducted once instantaneous channel state information changes. During each coherent interval, source keeps transmitting newly generated messages, and two selected relays successively decode forward source's to destination. particular, in one time slot, a jointly decodes both signals transmitted from...

We consider energy-harvesting cognitive radio (CR) systems with finite batteries. The energy-constrained secondary users (SUs) can be coordinated to enhance both the primary user (PU) detection and opportunistic utilization of PU spectrum. employ centralized cooperative spectrum sensing, optimal sensors are chosen from among SUs varied received signal power levels energy-arrival rates. finite-horizon partially observable Markov decision process (POMDP) is applied obtain cooperation for...

We formulate and study a multi-user multi-armed bandit problem that exploits the temporal–spatial opportunistic spectrum access (OSA) of primary user (PU) channels, so secondary users (SUs) who do not interfere with each other can make use same PU channel. first propose centralized channel allocation policy has logarithmic regret, but requires central processor to solve an NP-complete optimization at exponentially increasing time intervals. To overcome high computation complexity processor,...

In this paper, a downlink non-orthogonal multiple access (NOMA) system is studied, in which an intelligent reflecting surface (IRS) deployed to enhance the coverage by assisting cell-edge user device (UD) communicate with base station (BS). To characterize performance, new channel statistics for BS-IRS-UD link Nakagami-m fading are investigated. Based on statistics, closed-form expression outage probability derived. gain further insight into problem, diversity order obtained according...

Autofluorescence imaging with virtual histological staining has shown promising potential to improve the efficiency of postoperative histopathology workflow. Here, a widefield deep‐ultraviolet light‐emitting diode‐based system generate autofluorescence images human prostate tissue sections from 12 patients lateral resolution ≈1 μm is used. Subsequently, are transformed into hematoxylin and eosin‐stained via weakly supervised deep learning framework. The results assessed by four professional...