Browsing by Author "Panayirci, Erdal"

Now showing 1 - 7 of 7

Citation Count: 0
Breaking the Performance Gap of Fully and Semisupervised Learning in Electromagnetic Signature Recognition
(Ieee-inst Electrical Electronics Engineers inc, 2024) Panayırcı, Erdal; Wang, Qing; Chen, Luyong; Fu, Guanyang; Liu, Xiaofeng; Dong, Zhicheng; Panayirci, Erdal
Intelligent electromagnetic signature recognition is one of the key technologies in Internet of Things (IoT) device connection, which can improve system security and speed up the authentication process. In practical scenarios, as the number of IoT devices increases, electromagnetic features, such as fingerprint and modulation signals also increase substantially. However, since intelligent recognition technology, such as automatic modulation classification (AMC), requires a large amount of labeled data to train the neural network classifier, it is challenging to collect so much labeled data. To address the performance degradation challenges with small training data, we propose an efficient semisupervised electromagnetic recognition framework to break the performance gap with the fully supervised learning scheme. This framework can fully use the unlabeled electromagnetic data collected during the authentication process for self-training to improve the classifier's performance. According to the idea of consistency regularization, we design a signal augmentation method and propose an ensemble pseudolabel design algorithm to improve confidence. Moreover, we perform a convex combination of electromagnetic features to smooth the model decision boundary while generalizing to unknown data distribution regions. Experimental results on the modulated data demonstrate the performance superiority of the proposed algorithm, i.e., use less than 5% of data with no more than 10% performance drop.
Citation Count: 0
Energy-Efficient Design for RIS-Aided Cell-Free Ultra Dense HetNets
(Ieee, 2023) Panayırcı, Erdal; Hu, Yulin; Dong, Zhicheng; Panayirci, Erdal; Jiang, Huilin; Wu, Qiang
In this article, we investigate the energy efficiency of reconfigurable intelligent surfaces (RISs) aided full-duplex cellfree ultra dense hetNets (CFUDN), which has the advantages of both cell-free massive MIMO (CF-MMIMO) and ultra-dense hetNets (UDN). To maximize the EE of full-duplex CFUDN, users association and clustering, RISs subsurface associations are carefully designed. Then, the phase shift matrix of RISs and transmission power of base stations are jointly optimized. Due to the non-convexity and high complexity of formulated problem, it is extremely difficult to solve this problem. At present, the block coordinate descent (BCD) algorithm is the most commonly used method for joint optimization problems. However, as we all know, the BCD algorithm has some degree of performance loss due to alternate optimization. To overcome this challenging issue, a novel joint optimization framework based on Riemannian product manifolds (RPM) is proposed.
Citation Count: 53
Optical OFDM with Index Modulation for Visible Light Communications
(Ieee, 2015) Panayırcı, Erdal; Panayirci, Erdal
In this paper, we propose optical orthogonal frequency division multiplexing with index modulation (O-OFDM-IM) for visible light communications (VLC) systems employing light emitting diodes (LEDs) and photodetectors (PDs). The proposed scheme uses the indices of the active subcarriers of an optical OFDM system to transmit additional information bits. In the proposed scheme, the bipolar signals are asymmetrically clipped or DC biased and a log-likelihood ratio (LLR) calculation based detector is used to determine the indices of the active subcarriers. Our computer simulations show that the O-OFDM-IM achieves better error peformance compared to classical optical OFDM schemes.
Citation Count: 31
Orthogonal Frequency Division Multiplexing with Index Modulation in the Presence of High Mobility
(Ieee, 2013) Panayırcı, Erdal; Aygolu, Umit; Panayirci, Erdal
In this paper, a novel orthogonal frequency division multiplexing (OFDM) scheme, which is called OFDM with index modulation (OFDM-IM), is proposed for frequency-selective fading channels in the presence of high mobility. In this scheme, inspiring from the recently introduced spatial modulation concept for multiple-input multiple-output (MIMO) channels, the information is conveyed not only by M-ary signal constellations as in classical OFDM, but also by the indices of the subcarriers, which are activated according to the incoming bit stream. Different low complexity transceiver structures based on maximum likelihood (ML) detection or log-likelihood ratio (LLR) calculation are proposed. It is shown via computer simulations that the proposed scheme achieves significantly better error performance than classical OFDM.
Citation Count: 0
Physical Layer Security With DCO-OFDM-Based VLC Under the Effects of Clipping Noise and Imperfect CSI
(Ieee-inst Electrical Electronics Engineers inc, 2024) Panayirci, Erdal; Panayırcı, Erdal; Bektas, Ekin B.; Poor, H. Vincent
Visible light communications (VLC) and physical-layer security (PLS) are key candidate technologies for 6G wireless communication. This paper combines these two technologies by considering an orthogonal frequency division multiplexing (OFDM) technique called DC-biased optical OFDM (DCO-OFDM) equipped with PLS as applied to indoor VLC systems. First, a novel PLS algorithm is designed to protect the DCO-OFDM transmission of the legitimate user from an eavesdropper. A closed-form expression for the achievable secrecy rate is derived and compared with the conventional DCO-OFDM without security. To analyze the security performance of the PLS algorithm under the effects of the residual clipping noise and the channel estimation errors, a closed-form expression is derived for a Bayesian estimator of the clipping noise induced naturally at the DCO-OFDM systems after estimating the optical channel impulse response (CIR), by a pilot-aided sparse channel estimation algorithm with the compressed sensing approach, in the form of the orthogonal matching pursuit (OMP), and the least-squares (LS). Finally, from the numerical and the computer simulations, it is shown that the proposed PLS algorithm with secret key exchange guarantees the eavesdropper's BER to stay close to 0.5 and that the proposed encryption-based PLS algorithm does not affect the BER performance of the legitimate user in the system.
Citation Count: 2
Spatial Modulation Aided Physical Layer Security for NOMA-VLC Systems
(Ieee-inst Electrical Electronics Engineers inc, 2023) Panayırcı, Erdal; Koca, Mutlu; Haas, Harald; Poor, H. Vincent
We consider the physical layer security (PLS) problem in multi-user non-orthogonal multiple access (NOMA) enabled multiple-input multiple-output (MIMO) visible light communication systems intercepted by a passive eavesdropper (Eve). We propose a novel transmit precoding scheme based on receive spatial modulation (RSM) to degrade the signal-to-interference-noise ratio (SINR) of Eve by exploiting only the slow-fading characteristics of the visible light channel of the legitimate users (Bobs). The proposed PLS precoder is reinforced with secret parameter exchange with Bobs and a CSI acquisition model is proposed to reduce the PLS algorithm's computational load substantially at the transmitter. The closed-form expressions for the achievable secrecy rates and their upper and lower bounds are derived. Via Monte Carlo simulations, we confirm that Bobs can successfully decode their information in various user configurations while Eve's received SINR is significantly worsened by the jamming signal induced by the proposed precoder with secret key exchange. It is also shown that Eve's bit error rate (BER) is increased to the 0.5-level for almost any position in the considered indoor environment. Finally, we corroborate the derived secrecy expressions by computer simulations and show that the proposed scheme provides PLS for Bobs.
Citation Count: 2
Trellis Code Design for Spatial Modulation
(Ieee, 2011) Panayırcı, Erdal; Aygolu, Umit; Panayirci, Erdal
In this paper, we propose a novel multiple-input multiple-output (MIMO) transmission scheme, called trellis coded spatial modulation (TC-SM) in which a trellis (convolutional) encoder and a spatial modulation (SM) mapper are jointly designed similar to the conventional trellis coded modulation (TCM). A soft decision Viterbi decoder, which is fed with the soft information supplied by the optimal SM decoder, is used at the receiver. The pairwise error probability (PEP) upper bound is derived for the TC-SM scheme in uncorrelated quasi-static Rayleigh fading channels. From the PEP upper bound, code design criteria are given and then used to obtain new 4-, 8- and 16-state TC-SM schemes using QPSK (quadrature phase-shift keying) and 8-PSK modulations for 2 and 3 bits/s/Hz spectral efficiencies. It is shown via computer simulations that the proposed TC-SM schemes achieve significantly better error performance than their counterparts at the same spectral efficiency, yet with reduced decoding complexity.