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Large peak-to-average power ratio (PAPR) is the major issue in orthogonal frequency-division multiplexing (OFDM) systems. Selective mapping (SLM) has been commonly employed to reduce the PAPR. However, SLM requires side information (SI) which reduce the bandwidth efficiency. A low-complexity cyclic SLM (C-SLM) scheme without SI which uses delay correlation and matched filter, called C-SLM-DC-MF, has...
The implementation of channel estimation procedures in modern wireless networks exposes them to the risk of pilot contamination attacks. To protect the system from such types of malicious intervention, a recently proposed method, based on legitimate pilots from shifted constellations, can be applied. In this paper, the detection capability of this method is studied in both the presence and absence...
In this paper, a new cell selection technique is proposed for millimeter-wave (mm-wave) considering hybrid beamforming structure in data transmission stage. In order to reduce processing time for channel estimation, cell and beam synchronization signals (CBSS) are proposed which are simultaneously transmitted from multiple beams. It is shown by simulation that the proposed technique with the CBSS...
Compressed sensing (CS) based sparse channel estimation which sufficiently exploits the inherent sparsity of channels can achieve desirable performance compared with conventional channel estimation algorithms. However, in channel estimation common recovery algorithms, such as orthogonal matching pursuit (OMP), uses pilots inserted in one individual orthogonal frequency division multiplex (OFDM) symbol...
Underwater acoustic channel is a time varying, strong multipath, serious Doppler frequency shift, and high noise interference channel. Aiming at the requirements of strong stability and high reliability to support reliable transmission over long distance, a direct sequence spread spectrum based on single carrier underwater acoustic communication system using dual spread spectrum code (SC-CDMA/DSSC)...
The maximum likelihood (ML) estimation for multipath component (MPC) parameters requires high computational complexity, resulting in low efficiency in channel measurement campaigns. In this paper, a new method, called Fast Reduced-Dimension SAGE (FRDS) algorithm, is proposed to estimate the parameters such as excess delay, power, and angle-of-arrival/departure (AoA/AoD). By sounding channels using...
Underwater acoustic communication channels are characterized by a large variety of propagation conditions. Designing a reliable communication system requires knowledge of the transmission parameters of the channel, namely multipath delay spread, Doppler spread, coherence time, and coherence bandwidth. However, the possibilities of its estimation in a real-time underwater communication system are limited,...
We consider the problem of covariance estimation with projected or missing data, and in particular the application to spatial channel covariance estimation in a multi-user Massive MIMO wireless communication system with arbitrary (possibly time-varying and/or non-orthogonal) pilot sequences. We introduce batch and online estimators based on the expectation-maximization (EM) approach, and provide sufficient...
It is indispensable to take a low complexity and high accuracy channel estimation algorithm into account under rapidly growth in wireless communication. In this paper, we propose an algorithm for channel estimation using complementary sequence (CS). By utilizing the fantastic autocorrelation property of CS, time domain channel estimation can be easily achieved. We analyzed the complementary sequence,...
In the near future, digital subscriber line (DSL) network operators will start deploying G.fast technology to stay competitive in the broadband market. G.fast provides data rates of up to 1 Gbps, which is a 10× higher data rate than offered by the widely deployed very high speed DSL 2 (VDSL2) technology. In this paper we propose a novel algorithm to prequalify existing VDSL2 customers for G.fast services...
The fifth-generation (5G) wireless communication systems envision the deployment of massive multiple-input multiple-output (MIMO) technology for enhanced network coverage and capacity. With frequency division duplex (FDD) being the prominent mode of operation, addressing the challenges for massive MIMO systems in FDD is extremely important. One such challenge is the downlink channel estimation, which...
Nowadays, millimeter-wave communication centered at the 60 GHz radio frequency band is increasingly the preferred technology for near-field communication since it provides transmission bandwidth that is several GHz wide. The IEEE 802.11ad standard has been developed for commercial wireless local area networks in the 60 GHz transmission environment. Receivers designed to process IEEE 802.11ad waveforms...
We consider detection of spoofing relay attack in time-division duplex (TDD) multiple antenna systems where an adversary operating in a full-duplex mode, amplifies and forwards the training signal of the legitimate receiver. In TDD systems, the channel state information (CSI) can be acquired using reverse training. The spoofing relay attack contaminates the channel estimation phase. Consequently the...
A minimum mean square error estimation (MMSE) using a virtual pilot channel estimation scheme was proposed by our researchers for improving the error performance of the IEEE 802.11p. However, compared to the STA channel estimation scheme, the MMSE scheme cannot provide an acceptable error performance in a low SNR region. To alleviate this, we propose an adaptive channel estimation scheme, which selectively...
Providing short-message communication and simultaneous channel estimation for sporadic and fast fading scenarios is a challenge for future wireless networks. In this work we propose a novel blind communication and deconvolution scheme by using Huffman sequences, which allows to solve three important tasks at once: (i) determination of the transmit power (ii) identification of the instantaneous discrete-time...
In this paper, we shall develop a generic channel estimation framework based on the convex formulation for dense cloud radio access networks (Cloud-RAN). Due to the training resource constraint and the large number of transmit antennas, the pilot length is smaller than the antenna number, and thus channel estimation becomes an ill-posed inverse problem. By observing that the wireless channel possesses...
A new method of applying EMD (empirical mode decomposition) algorithm to realize the CFO (carrier frequency offset) estimation of single channel OFDM (orthogonal frequency division multiplexing) system is proposed in this paper. Firstly, the observation signal is extracted by using correlation detection technology to process the received OFDM signal. Then the data with CFO information is obtained...
With the rapid deployment of the high speed railway (HSR), the wireless communication in HSR has been one of the indispensable scenarios in the fifth generation (5G) communications. In order to improve the performance of the orthogonal frequency division multiplexing (OFDM) system in the HSR scenarios, we propose an enhanced linear minimum mean square error channel estimation scheme based on multi-path...
Our aim is to investigate long range predictions (up to several wavelengths) of the small-scale fading of radio channels. The purpose is to enable advanced 5G downlink transmission schemes that require accurate channel state information at transmitters, such as massive MIMO and coherent joint transmission, for vehicular users.
The estimation of the noise power is a core issue in wireless communication systems. In broadcasting, every OFDM frame starts with a preamble symbol, which facilitates the noise power estimation. However, the performance of preamble-based noise estimation schemes worsens in fast-changing environments and cannot efficiently track the noise variation well. In order to track the noise variation symbol...
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