Browsing by Author "Dong, Zhicheng"

Now showing 1 - 11 of 11

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: 13
Conditional Power and Rate Adaptation for MQAM/OFDM Systems Under CFO With Perfect and Imperfect Channel Estimation Errors
(IEEE-INST Electrical Electronics Engineers Inc, 2015) Dong, Zhicheng; Fan, Pingzhi; Panayırcı, Erdal; Lei, Xianfu
In this paper a new conditional power and rate adaptation scheme for orthogonal frequency-division multiplexing (OFDM) systems is proposed in the presence of carrier frequency offset (CFO) with perfect and imperfect channel state information (CSI). The conventional adaptive scheme is shown to be a special case of the conditionally adaptive scheme technique that enables the resulting nonconvex optimization problem which is solved in a feasible way. It leads to a solution for optimal power adaptation that maximizes the spectral efficiency of an OFDM system using M-ary quadrature amplitude modulation (MQAM) under average power and instantaneous bit error rate (BER) constraints. Closed-form expressions for the average spectral efficiency (ASE) of adaptive OFDM systems are derived for perfect and imperfect CSI cases. The theoretical results and computer simulations show that range of the conditional adaptation becomes narrow and the performance of constant power and continuous rate is very close to that of the conditionally adaptive power and continuous rate for higher CFO or high signal-to-noise ratio (SNR) values.
Citation Count: 13
Effect of power and rate adaptation on the spectral efficiency of MQAM/OFDM system under very fast fading channels
(Springer International Publishing Ag, 2012) Panayırcı, Erdal; Fan, Pingzhi; Panayırcı, Erdal; Mathiopoulos, P. Takis
In this article the effect of power and rate adaptation on the spectral efficiency of orthogonal frequency division multiplexing (OFDM) systems using M-ary quadrature amplitude modulation (MQAM) is investigated in the presence of frequency selective and very rapidly time-varying fading channels under power and instantaneous bit error rate (BER) constraints. Lower bounds on the maximum spectral efficiency of adaptive OFDM/MQAM systems with perfect and imperfect channel state information (CSI) are obtained together with a closed-form expression for the average spectral efficiency of adaptive OFDM systems. The delay between the channel estimation and the actual transmission is also considered in this article. The theoretical and numerical results show that the adaptive MQAM/OFDM systems under fast fading channels have substantial gains in spectral efficiency over the non-adaptive counterparts with perfect CSI or moderate imperfect CSI. The theoretical and numerical results also show that a good way to deal with the delay CSI under very rapidly time-varying channels is to increase the subcarrier bandwidth of the OFDM system while ignoring the impact of the cyclic prefix.
Citation Count: 0
An Efficient SAGE-based Data Detection Algorithm for OFDM Systems in the Presence of Very Fast Fading Channels
(IEEE, 2013) Dong, Zhicheng; Fan, Pingzhi; Panayırcı, Erdal
In this paper an iterative and computationally efficient data detection algorithm is proposed based on the space alternating generalized expectation maximization (SAGE) technique for orthogonal division multiplexing (OFDM) systems under fast fading channels. The proposed detector includes the original detector presented in [1] as one of its special cases. With a proper choice of its parameters simulations show that the new detector has negligible performance loss than original one in [1] with smaller number of iterations.
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: 28
Energy-Efficient Resources Allocation with Millimeter-Wave Massive MIMO in Ultra Dense HetNets by SWIPT and CoMP
(Institute of Electrical and Electronics Engineers Inc., 2021) Yonghong Dai, Bin Li,; Dong, Zhicheng; Panayırcı, Erdal; Jiang, Huilin; Jiang, Hao
Ultra-dense HetNets (UDN)-based Millimeter-Wave (mmWave) massive MIMO is considered a promising technology for 5th generation (5G) wireless communications systems since it can offer massively available bandwidth and improve energy efficiency (EE) substantially. However, in UDN, the power consumption of the system increases sharply with the increase of network density. In this paper, we investigate the optimization of the EE in the mmWave massive MIMO systems with UDN. To develop the functions of massive MIMO, we first propose a system model where the massive MIMO harvests electromagnetic energy from the environment employing simultaneous wireless information and power transfer (SWIPT) technology, implemented at the base station (BS). Then, the EE optimization problem is formulated for 5G mmWave massive MIMO systems within the UDN. Considering the nonconcave feature of the objective function, an iterative EE algorithm is developed, based on Dinkelbach method. To utilize the role of coordinated multi-point transmission and reception (CoMP) for improving the EE, a coordinated user(UE)-BS association algorithm-based CoMP with maximum energy efficiency (MaxEE) is proposed. The simulation results demonstrate that the proposed algorithm has a substantially faster convergence rate and is very effective, compared with existing methods.
Citation Count: 8
An Improved Adaptive Subspace Tracking Algorithm Based on Approximated Power Iteration
(IEEE-INST Electrical Electronics Engineers Inc, 2018) Panayırcı, Erdal; Zheng, Jian-Sheng; Dong, Zhicheng; Panayırcı, Erdal; Wu, Zhi-Qiang; Ren, Qingnuobu
A subspace tracking technique has drawn a lot of attentions due to its wide applications. The main objective of this approach is to estimate signal or noise subspace basis for the sample covariance matrix. In this paper we focus on providing a fast stable and adaptive subspace tracking algorithm that is implemented with low computational complexity. An alternative realization of the fast approximate power iteration (FAPI) method termed modified FAPI (MFAPI) is also presented. Rather than solving an inverse square root of a matrix employed in the FAPI the MFAPI applies the matrix product directly to ensure the orthonormality of the subspace basis matrix at each recursion. This approach yields a simpler derivation and is numerically stable while maintaining a similar computational complexity as compared with that of the FAPI. Furthermore we present a detailed mathematical proof of the numerical stability of our proposed algorithm. Computer simulation results indicate that the MFAPI outperforms many classical subspace tracking algorithms particularly at the transient-state step.
Citation Count: 0
Partial Power and Rate Adaptation for MQAM/OFDM Systems under CFO
(IEEE, 2014) Dong, Zhicheng; Fan, Pingzhi; Panayırcı, Erdal; Lei, Xianfu
In this paper a new partial power and rate adaptation scheme for orthogonal frequency division multiplexing (OFDM) systems is proposed in the presence of carrier frequency offset (CFO). The conventional adaptive scheme is shown to be a special case of the partially adaptive scheme technique which enables the resulting non-convex optimization problem solved in a feasible way. It leads to a solution for optimal power adaptation that maximizes the spectral efficiency of an OFDM system using M-ary quadrature amplitude modulation (MQAM) under average power and instantaneous BER constraints. Closed-form expressions for the average spectral efficiency (ASE) of adaptive OFDM systems are derived. The theoretical results and computer simulations show that the range of the partial adaptation becomes narrow and the performance of constant power and continuous rate is very close to that of the partially adaptive power and continuous rate for higher CFO or high signal noise ratio (SNR) values.
Citation Count: 4
Power and Rate Adaptation Based on CSI and Velocity Variation for OFDM Systems Under Doubly Selective Fading Channels
(IEEE-INST Electrical Electronics Engineers Inc, 2016) Dong, Zhicheng; Fan, Pingzhi; Lei, Xianfu; Panayırcı, Erdal
In this paper a novel joint continuous power and rate adaptation scheme is proposed fordoubly selective fading channels in orthogonal frequency division multiplexing (OFDM) systems based on terminal velocity and perfect or imperfect channel state information (CSI). The analysis and simulation results show that the continuous power and rate adaptation scheme is very effective and improve the performance of OFDM systems substantially under time-varying fading channels as compared with the traditional adaptation schemes operating without a priori knowledge of velocity and mobility adaptation without CSI.
Citation Count: 1
Power and rate adaptation for MQAM/OFDM systems under fast fading channels
(IEEE, 2012) Dong, Zhicheng; Fan, Pingzhi; Zhou, Weixi; Panayırcı, Erdal
In this paper the effect of power and rate adaptation on the spectral efficiency of orthogonal frequency division multiplexing (OFDM) systems using M-ary quadrature amplitude modulation (MQAM) is investigated in the presence of the fast fading channels under power and instantaneous bit error rate (BER) constraints. A lower bound on the maximum spectral efficiency of adaptive OFDM/MQAM systems is obtained together with a closed-form expression for the average spectral efficiency of adaptive OFDM systems. Theoretical and numerical results show that the adaptive MQAM/OFDM systems under fast fading channel have substantial gain in spectral efficiency over the non-adaptive counterparts.
Citation Count: 0
Research on Power Distribution Method of OFDM System with Hybrid Energy Supply under Fast Fading Channel
(IEEE, 2021) Liu, Yipeng; Dong, Zhicheng; Xiao, Wei; Panayırcı, Erdal
An adaptive power allocation by minimizing grid power consumption for the Orthogonal Frequency Division Multiplexing (OFDM) system with the hybrid energy supply under a fast fading channel is proposed in this paper. To solve the non-convex problem, two adaptation algorithms have been presented. The first is Lagrangian algorithm and the second is a successive convex approximation (SCA) algorithm. The theoretical analysis and simulation results show that the proposed algorithms are effective. Compared with traditional OFDM systems with grid energy supply only, the proposed algorithms can reduce the power consumption of the grid. Also, different proposed algorithms have different performance. Lagrangian algorithms with higher computational complexity have better performance. However, there is a trade-off between computational complexity and performance.