- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Suppression of Speckle Noise in Digital Holography With Spatial and Temporal Domain Depolarization
摘要： In this paper, we introduce transmit antenna selection/maximal-ratio combining (TAS/MRC) scheme in dual-hop randomize-and-forward (RaF) cognitive multiple-input multiple-output (MIMO) wiretap networks with outdated channel state information (CSI). In this network, the secondary transmitter adopts the TAS scheme to choose the antenna with the maximal received signal-to-noise ratio (SNR), while the secondary receiver and the eavesdropper adopt the MRC scheme to combine the received signals. To thoroughly assess the secrecy performance achieved by the TAS/MRC scheme and the impact of outdated CSI on the secrecy performance, we derive a new closed-form expression for the secrecy outage probability of dual-hop RaF cognitive MIMO wiretap networks. In order to achieve more insights on the application of TAS/MRC scheme, we further present tractable asymptotic secrecy outage probability at high SNR regimes under two distinct scenarios. From our analysis, several important concluding remarks are obtained as follows: 1) the RaF relaying strategy achieves better secrecy performance than that of the decode-and-forward relaying strategy for dual-hop cognitive MIMO wiretap networks; 2) outdated CSI decreases the secrecy diversity gain of the TAS/MRC scheme from NR min (NA, NB) to min (NR, NB); and 3) although TAS/MRC scheme cannot attain full secrecy diversity gain for the considered system with outdated CSI, it still can achieve an extra secrecy coding gain compared with the random antenna selection/MRC scheme.
关键词： Cognitive radio networks,secrecy outage probability,MIMO,outdated channel state information
更新于2025-09-19 17:13:59
-
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 Due to fast fading statistics of the ?rst RF hop, it is assumed that the channel state information of the RF link is outdated, which is used for both relay gain adjustment and PRS procedure.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