In this paper, we report the first all-optical solution for multi-false-target range-velocity compound deception jamming based on frequency-comb-enabled photonic RF memory (PRFM). The operation frequency of current digital RF memory (DRFM) in electronic countermeasures is severely limited by low-speed digital devices. Since optical processing has a larger bandwidth and higher speed, it is valuable to develop advanced functions of PRFM. Our method skillfully applies a carrier-signal separation strategy to enhance the performance and extend the functions of PRFM. By bandwidth-optimized storage of the RF signal, the ASE noise accumulation and high-power optical self-oscillations can be effectively suppressed, contributing to a significant improvement of the signal SNR. On the other hand, by comb modulation of the optical carrier, the beaten signal contains multiple coherent false targets with different range-velocity deception information. In our experiment, the maximum storage time has exceeded$840~\mu $s with less than 10 dB SNR degradation, and the storage signal frequency has reached 16 GHz. Furthermore, more than 10 false targets have been obtained in the 10 dB bandwidth simultaneously, with the SNR consistently close to 40 dB. The outstanding storage and jamming performance allows our scheme to promote the deployment and upgrade of PRFM in electronic countermeasures.

In this paper, we propose a novel physical layer security optical transmission scheme utilizing randomized quantization noise. The proposed approach encrypts low-order plaintext signals into ultra-high-order ciphertext using principles similar to quantum noise stream cipher (QNSC). While, the ultra-dense quadrature amplitude modulation (QAM) ciphertext waveforms are masked by intrinsic quantization noise. The combination of digital delta-sigma quantization and analog chaotic random scrambling not only produces randomized quantization noise, but also naturally supports one-time processing of masking ciphertext and generating keystream. Whereby, the in-band quantization noise (IBN) conceals nearby ciphertext levels bolstering security, and the out-of-band quantization noise (OOBN) is digitized to generate keystream using the Toeplitz hashing extractor. Experimental results show that 256-QAM plaintext signals were securely transmitted over standard single-mode fiber: 163-Gbps signals over 400 km, and 79.7-Gbps signals over 1800 km. To evaluate system performance, theoretical models for signal-to-noise ratio (SNR), bit error rate (BER), and number of masked signals (NMS) are derived as functions of the oversampling ratio (OSR). Our findings reveal a trade-off between transmission performance and security performance. Our results confirm that this scrambling effectively eliminates the correlation between the masking noise components. Toeplitz hashing extractor can effectively reduce the complexity of keystream generation and obtain a source-independent random keystream.

Reconfigurable intelligent surface (RIS) with massive passive reflecting elements can greatly improve the wireless propagation environment. Although the RIS is easily introduced into the existing multiple-input multiple-output (MIMO) systems, effectively supporting MIMO technologies is still a major challenge in millimeter-wave cloud radio access networks (mmWave C-RANs) with fiber-wireless fronthaul. Herein, an optical true time delay pool-based hybrid beamforming (OTTDP-HBF) scheme, enabling centralized analog beamforming control, is proposed for the RIS-aided mmWave C-RAN. In the OTTDP-HBF scheme, the physical implementation and the computational processing of analog beamforming are decoupled from all active antenna units (AAUs) and centrally deployed. For the RIS-aided mmWave CRAN with OTTDP-HBF, we develop a two-stage precoding (TSP) algorithm, where the complex joint optimization problem of hybrid precoding matrices and the phase-shift matrix for the RIS is formulated as an alternating optimization (AO) problem and a sparse reconstruction problem. For an AAU equipped with 8 antennas, a designed example of the proposed OTTDPHBF is presented, where the performance can be significantly improved by introducing the RIS into mmWave C-RANs. Moreover, the obtained results of different schemes show that the proposed TSP algorithm is effective for the RIS-aided mmWave C-RAN with OTTDP-HBF.

Summary form only given. Pfair scheduling for periodic tasks on multiple processors in a time slotted environment can not only guarantee task deadlines to be respected, but also make tasks execute at steady progressive rates. We consider pfair schedulability of periodic tasks with allocation constraints in the sense that some tasks can only be assigned to one or more specified processors. The contributions of the paper lie in the following four aspects. Firstly, we prove that there exists pfair schedule in the case that fixed tasks are assigned to disjoined processor subsets. Secondly, we give a sufficient and necessary condition of the existence of pfair schedule for periodic tasks with arbitrary allocation constraints. Thirdly, we show that pfair schedulability test of periodic tasks with arbitrary allocation constraints can be done in polynomial time. Finally, an online approximate pfair scheduling algorithm called HPA (hierarchical pfair algorithm) is proposed for scheduling fixed and migrating tasks. With HPA although idea a fixed task is not guaranteed to respect its deadline completely, the amount of time by which it misses its deadline is bounded.

In this paper we propose a frame-oriented scheduling discipline, EDF-RR (earliest-deadline-first round-robin), for OQ (output-queued) switch architecture and data traffic consisting of fixed-length cells. Bandwidth reservation for an active session is performed by holding a number of cell slots for the session in frames. Each cell that is going to be transferred in a frame is assigned a virtual release time and a virtual deadline according to the bandwidth reservation scheme. The transmitting order of the cells in frames is thus determined by nonpreemptive nonidling EDF algorithm so that cells of a backlogged session in frames are distributed as uniformly as possible. Through the analysis applying real-time scheduling theory and network calculus as well as network simulation, EDF-RR takes the advantage of low computational complexity, and possesses tight delay bounds and lenient buffer requirements. The proposed scheduling discipline is appropriate for distributed real-time systems as we show that sessions can be configured based on message traffic models and deadline requirements. Also, a modified version of EDF-RR, called EDF-DRR, can be applied as traffic regulator when jitter requirements exist among active sessions.