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[IEEE 2019 28th Wireless and Optical Communications Conference (WOCC) - Beijing, China (2019.5.9-2019.5.10)] 2019 28th Wireless and Optical Communications Conference (WOCC) - Secrecy Performance Analysis for Hybrid Satellite Terrestrial Relay Networks with Multiple Eavesdroppers
摘要： In this paper, we investigate the secrecy performance of hybrid satellite terrestrial relay networks (HSTRN) with multiple eavesdroppers, particularly, all nodes in the networks are equipped with single antenna, respectively. In addition, we propose two selection schemes in the networks, namely, Case I, which means choosing the larger secrecy capacity among Satellite-Relay and Relay-Destination ; Case II, which is choosing the lower secrecy capacity among Satellite-Relay and Relay-Destination. Furthermore, we derive the closed-form expressions for the secrecy outage probability (SOP) of the HSTRN based on the proposed two selection schemes, which provide a fast means to evaluate the impact of system parameters and selection schemes on the secrecy system performance. In order to study the impact of system parameters and selection schemes at high SNRs, we obtain the asymptotic expressions of the SOP of the HSTRN. Finally, in order to verify the accuracy of the analysis described in this paper, simulation results are given.
关键词： joint eavesdropping scheme,secrecy outage probability (SOP),Hybrid Satellite Terrestrial Relay Networks (HSTRN)
更新于2025-09-11 14:15:04
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Exact Outage Probability Analysis of the Mixed RF/FSO System with Variable Gain Relays
摘要： This paper presents an uni?ed analysis of the mixed radio-frequency/free-space optics (RF/FSO) relaying system, with multiple variable gain amplify-and-forward relays. The partial relay selection (PRS) is employed to select the active relay for further re-transmission. Due to fast fading statistics of the ?rst RF hop, it is assumed that the channel state information of the RF link is outdated, which is used for both relay gain adjustment and PRS procedure. The RF hops are subject to the Rayleigh fading, while the FSO hop is affected by the atmospheric turbulence and the pointing errors. The intensity ?uctuations of the optical signal caused by atmospheric turbulence are modeled by general M′alaga (M) distribution, which takes into account effect of multiple scattered components. Exact expression for the outage probability is derived. In addition, high signal-to-noise ratio approximations are provided, which can be used to ef?ciently determine the outage probability ?oor. Numerical results are validated by Monte Carlo simulations, which are used to examine the effects of the system and channel parameters on the RF/FSO system performance.
关键词： Free-space optical systems,partial relay selection,variable gain relays,outage probability,outdated channel state information,radio frequency systems
更新于2025-09-11 14:15:04
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Deployment Issues and Performance Study in a Relay-Assisted Indoor Visible Light Communication System
摘要： This paper investigates the deployment issues and analyzes the performance of a relay-assisted indoor visible light communications (VLC) system with dc-biased optical orthogonal frequency division modulation (DCO-OFDM). The study considers two light sources in an office environment. One light source works as the information source and is located at the ceiling while the other one works as the relay terminal, which usually is a desk light or a floor light. We analyze the general blockage in a room, discuss the path loss of the VLC channel, and compare received signal power from a line of sight (LOS) link and a non-LOS link. The constraints on the relay height in order to achieve LOS connection are investigated. Simplified optimal power allocation under illumination and blockage constraints is proposed. Bit error rate performance is analyzed and the required signal power is derived for the relay-assisted DCO-OFDM VLC system. The study shows that in a relay-assisted VLC system, the blockage of source to destination link has trivial influence on the overall system performance if relays are properly deployed.
关键词： indoor,visible light communications (VLC),dc-biased optical orthogonal frequency division modulation (DCO-OFDM),relay,Channel model,power allocation
更新于2025-09-09 09:28:46
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[IEEE 2018 15th European Radar Conference (EuRAD) - Madrid, Spain (2018.9.26-2018.9.28)] 2018 15th European Radar Conference (EuRAD) - Multiplier-less Correlator for Noise SAR Imaging
摘要： Correlation function estimate using one-bit reference signal is described and results of FPGA-based implementation of multi-channel time-integrating correlator without multiplication operation (multiplier-less correlator) is described. Results of experimental evaluation of the suggested multiplier-less relay correlator in Innovative Integration X6-1000M board with Xilinx Virtex-6 FPGA and arbitrary waveform generator Euvis AWG472 are presented.
关键词： Relay Correlator,Field Programmable Gate Arrays,Noise Radar,Radar Imaging,Synthetic Aperture Radar
更新于2025-09-09 09:28:46
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Joint user and relay selection for relay-aided RF/FSO systems over Exponentiated Weibull fading channels
摘要： In this paper, we investigate the performance of joint user and relay selection scheme for a multi-user relayed network over mixed radio-frequency (RF) and free space optical (FSO) system. In this set-up, the non-line-of-sight (NLOS) RF link is modeled with Rayleigh fading whereas the LOS FSO path is modeled with Exponentiated Weibull (EW) distribution. We assume that the multiple users at source terminal communicate with the destination over multiple decode and forward relays which are located at the rooftops of the buildings to provide a perfect LOS path. In the proposed scheme, all users send pilot signals to the destination through relay terminals and the latter jointly selects the best user and relay based on the maximization of the end-to-end signal-to-noise ratio (SNR). To quantify the performance of the proposed scheme, closed form outage and error probability are derived. Moreover, asymptotic analysis is performed to obtain important system parameters including fading severity, number of users and relays in the system. Finally, Monte-Carlo (MC) simulations are carried out the verify the performance of the considered scheme.
关键词： Exponentiated Weibull fading channel,Joint user and relay selection,Free space optical communication,relay aided transmission
更新于2025-09-04 15:30:14
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[IEEE 2018 1st International Cognitive Cities Conference (IC3) - Okinawa, Japan (2018.8.7-2018.8.9)] 2018 1st International Cognitive Cities Conference (IC3) - Relay Lens Design for Image Reduction Applications
摘要： Relay lens is the lens used for transfer an object to the intermediate image plane or directly to enlarge or reduce the object with some magnifications. The design addressed in the study is to reduce an 1mm2 object to 0.5mm image spot size. A Gaussian image theory helps to investigate the initial configuration and potential solutions. The final design reaches high image performance.
关键词： aberration,Lens design,relay lens
更新于2025-09-04 15:30:14
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Precoding Design for Full-Duplex Transmission in Millimeter Wave Relay Backhaul
摘要： As the amount of user equipment and massive volumes of data continue to increase, high data rate requirements remain a major challenge, particularly in cellular networks. In networks composed of small cells, applying full-duplex (FD) millimeter wave (mmWave) wireless backhauls is a more effective and convenient approach than utilizing conventional optical fiber links. The mmWave communication technology is promising for future wireless communications due to its considerable available bandwidth, which is the basis of a high transmission rate. However, the short wavelength of mmWave leads to high propagation loss and shortens the transmission distance of the system. FD relaying can expand the coverage of the base station and achieve higher spectral efficiency than half-duplex (HD) transmission. However, the residual self-interference (SI) may degrade the performance of FD. The combination of mmWave and FD technologies compensates for the high path loss and realizes efficient transmission. In this paper, we consider an FD mmWave relay backhaul system and the SI of FD communication. We first propose an FD SI channel model in the mmWave band, which is composed of two parts: line-of-sight (LOS) SI and non-line-of-sight (NLOS) SI. According to the special mmWave MIMO structure limitation, two SI cancellation precoding algorithms are proposed to eliminate the SI in the system and achieve high spectral efficiency. The decoupled analog-digital algorithm eliminates the SI by utilizing the zero space of the channel, and the enhanced algorithm achieves higher performance. The spectral efficiency of the subconnected structure is analyzed. With appropriate performance loss, the simplified structure achieves significantly low configuration complexity.
关键词： precoding,Millimeter wave,Full-duplex,Relay,Self-interference
更新于2025-09-04 15:30:14