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While the establishment of secret encryption keys based on reciprocal electromagnetic propagation has received recent attention, very limited work has appeared regarding how multiantenna radios should conduct the required channel estimation in the presence of an eavesdropper. This paper demonstrates array beamforming that maximizes the number of bits that can be established when an eavesdropper observes...
In mobile communication systems such as LTE, Hybrid-ARQ (HARQ) schemes based on Turbo codes have proved to be very effective in ensuring reliable transmission. However, several modified HARQ and Turbo decoding strategies have been recently developed to further improve performance. This paper proposes an enhanced coding scheme for LTE which couples a modified Turbo coding strategy with Reliability...
The state estimation of complex dynamical networks with time delay coupling under noisy transmission channel is studied in this paper. In order to suppress the effect introduced by the noise and time-varying delay, the state estimation controllers are designed by using integral control approach. A sufficient condition for state estimation is derived by using Lyapunov stability theory and H− Hcontrol...
A space time code based partial rank affine projection (PRAP) algorithm is proposed. The proposed algorithm uses an input signal where the input signal matrix Xk becomes an orthogonal matrix. For this input signal, matrix (XkTXk) becomes a diagonal matrix whose inverse can be easily computed. Thus, the proposed algorithm saves a significant amount of computations. Due to this feature the proposed...
Recently, compressive sensing (CS) algorithms have been adopted to improve the accuracy of channel estimation for wide-band wireless communication systems. Since the wireless channel is usually time and frequency doubly selective fading, the performance of CS based channel estimation is limited by the estimation accuracy of the channel's sparsity level. In this paper, an adaptive subspace pursuit...
In this work, we propose a robust cooperative relay beamforming (rBF) design for single-carrier frequency-division multiple access (SC-FDMA) based multiuser multi-relay systems with imperfect channel state information. We maximize a lower bound on the achievable bit rate (ABR) of the network, subject to an aggregate relay transmit power constraint. Employing the primal decomposition technique, we...
Compressive sensing (CS) has recently attracted lots of attention and has been extended to more structured architectures, for example the linear time-invariant system identification. However, prevalent CS methods used for channel estimation, such as Basis Pursuit Denoising (BPDN) and Dantzig selector (DS), require computational complexity as high as O(N3), where N is the length of the channel. When...
In this paper, equalization of multihop relaying orthogonal frequency division multiplexing (OFDM) signal is investigated under time-varying channel with unknown noise powers, channel orders and Doppler frequencies. An iterative algorithm is developed under variational expectation maximization (EM) framework. The proposed algorithm iteratively estimates the channel, learns the channel and noise statistical...
This paper is concerned with distributed estimation of a scalar parameter using a wireless sensor network (WSN) that employs a large number of sensors operating under limited bandwidth resource. A semi-orthogonal multiple-access channel (MAC), which provides transmission of observations from K sensors to a fusion center (FC) via N (N ≤ N) orthogonal channels, is studied. The K sensors are divided...
Compressed sensing (CS) technique has attracted a lot of recent research interests in mathematics and signal processing fields. Literature studies often exploit CS at the receiver side to sub-sample the receiving signals to reduce the sampling rate and processing overhead. It would be of great benefit if it is possible to exploit CS at the transmitter side to reduce the redundancy of the data before...
Generating secret keys from radio channel measurements has been shown to allow private communications. Previously described methods for performing wireless key generation have not come close to achieving the theoretical upper bounds on key rates theory for this technique. This paper demonstrates how using a Kalman filter based on an auto-regressive (AR) model for the channel process, channel gain...
This paper is concerned with a challenging problem of channel estimation for amplify-and-forward cooperative relay based orthogonal frequency division multiplexing (OFDM) systems in the presence of sparse underwater acoustic channels and of the correlative non-Gaussian noise. We exploit the sparse structure of the channel impulse response to improve the performance of the channel estimation algorithm,...
Nowadays the use of voice recognition system is increasing day by day. Dereverberation of speech signal is necessary to make this voice recognition system effective and smooth. Beamforming technique and an adaptive process are useful for blind channel estimation which can be used for dereverberation process. Reverberated channel estimation is a very important step for de-reverberation process. This...
In through-the-wall radar applications, multipath effects due to room reverberations result in various undesirable phenomena including target-shift, image defocusing and false alarms. Under the sparse channel assumption proved by finite difference time domain simulations, this paper proposes a blind multipath channel estimation approach by extending the blind compressive sensing dictionary learning...
n this paper, we introduce a three-phase transmis- sion scheme for cloud radio networks against eavesdropper. We study the security and reliability performance of this scheme in the form of intercept probability and outage probability, respectively. Channel estimation error is considered in our study instead of assumption of perfect channel state information. It is found that the security-reliability...
The usage of Minimum Mean Square Error - Interference Rejection Combining (MMSE-IRC) receivers is expected to be a significant performance booster in the ultra-dense deployment of small cells envisioned by an upcoming 5th generation (5G) Radio Access Technology (RAT). However, hardware limitations of the radio- frequency front-end and poor covariance matrix estimation may severely compromise its ideal...
Attracting increasing attention in recent years, the Free Space Optics (FSO) technology has been recognized as a cost-effective wireless access technology for multi-Gigabit rate wireless networks. Radio over Free Space Optics (RoFSO) provides a promising enhancement to optical fiber systems. In an RoFSO system using wavelength-division multiplexing (WDM), it is possible to concurrently transmit multiple...
Frequency offset (FO) is an inherent feature of wireless communications. It results from differences in the operating frequency of different radio oscillators. Failure to compensate for the FO may lead to a decoding failure, particularly in OFDM systems. IEEE 802.11a/g systems use a globally known preamble to deal with this issue. In this paper, we demonstrate how an adversary can exploit the structure...
Compressed Sensing (CS) is a new mathematical concept, which can reconstruct the original signal accurately with lower Nyquist sampling. Besides, multipath arrivals in an Ultra-wideband (UWB) channel have a long time intervals between clusters and rays where the signal takes on zero or negligible values. It is precisely this signal sparsity of the impulse response of the UWB channel that is suitable...
This paper presents a novel sequence detection algorithm well-suited for data transmission and wake-up receiver addressing in FSK-based narrowband power line communication applications, where the communication channel is characterized by non-white noise, interferers and frequency-selective signal attenuation. The algorithm is discussed in detail, verified by Monte Carlo simulations and compared to...
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