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The problem of compressed sensing (CS) is considered in two-dimensional (2D) sparse decomposition measurement model. Correspondingly, a novel recovery algorithm — modified 2D subspace pursuit (M-2DSP) algorithm is proposed with the available prior support and chunk sparse structure. The massive multi-input multi-out (MIMO) system show a concealed sparse structure and temporal correlation in the user...
The channel estimation is one of the essential components to make the long distance transmission of continuous variable quantum key distribution (CV-QKD). In this paper we provide the Cramer-Rao lower bound (CRLB) of the channel estimator, which is the minimum variance that an estimator can achieve. We compare CRLB with the channel transmission parameter estimator proposed in [15] for long distance...
Considering the three dimensional (3D) channel with elevation effect, a two dimensional (2D) antenna array was employed in a generic ray-based 3D multi-input multi-output (MIMO) system. Through utilizing the channel spatial correlation between antennas at the transmitter side, we propose a cascaded MMSE channel estimation with low computational complexity. Numerical results show that the proposed...
Channel estimation is an important issue in orthogonal frequency division multiplexing (OFDM) systems to improve the performance of system. For OFDM based IEEE 802.11ad wireless local area network (WLAN), two types of symbols, training symbols and pilot symbols, can be used for channel estimation in the OFDM receiver. We analyze the algorithms of channel estimation methods based on symbol types, training...
Localization, a process of determining the position of a blind node, can be used in various applications. Signal-strength localization provides a low-cost and lowpower solution to positioning. Signal-strength positioning approaches using fingerprinting or calibrated approaches require a time-consuming calibration phase. Existing selfcalibrating approaches, which do not require a priori calibration,...
In multichannel systems, acoustic time delay estimation (TDE) is a challenging problem in reverberant environments. Although blind system identification (BSI) based methods have been proposed which utilize a realistic signal model for the room impulse response (RIR), their TDE performance depends strongly on that of the BSI, which is often inaccurate in practice when the identified responses are under-modelled...
In this paper, we present a close-form expression for the downlink throughput of a massive MIMO system with finite antenna elements in a multi-celluar systems. In practice, the performance of massive MIMO system is limited by the number of antenna elements. From the operator aspect, the cost of massive MIMO is a major concern. Thus, a massive MIMO system with finite antenna elements is of interest...
Widely linear (WL) receivers can fulfill single antenna interference cancellation (SAIC) of one rectilinear (R) or quasi-rectilinear (QR) co-channel interference (CCI). The SAIC technology for QR signals has been shown to be less powerful than SAIC for R signals. To overcome this limitation, a SAIC/MAIC enhancement using three-inputs WL frequency-shift (FRESH) receiver has been introduced for QR signals...
Massive multiple-input multiple-output (MIMO) is a key technology driving the 5G evolution. It relies on the use a large number of antennas at the base-station to improve network performance. The performance of massive MIMO systems is often limited by imperfect channel estimation because of pilot contamination. Recently, several channel estimation techniques have been proposed to minimize the performance...
We propose a method for channel estimation in orthogonal frequency division multiplexing (OFDM) systems with an array of receiving elements. In contrast to traditional methods, which target the equivalent sample-spaced channel taps, this method targets the physical propagation paths whose delays are not restricted to the sample-spaced grid. The path delays are estimated jointly with the path gains...
By taking the imperfect channel state information(CSI) into account, the optimal precoding matrix is deduced with the proposition that the full CSI of the source-relay link and the estimation errors and antennas correlation information of the relay-destination link are known by the relay node. Considering the maximum power constraint at the relay node, the precoding matrix is optimized based on the...
This paper concerns on inefficiency or even failure in secret key generation caused by the imperfect channel state information. We propose a secret key generation scheme based on wavelet analysis. Firstly, the channel estimates are pre-processed by wavelet analysis to improve the correlation. Secondly, to ensure the randomness of the secret keys, an adaptive equal probability quantization approach...
In this paper a new interference mitigation scheme with resource control is proposed, to achieve the objective of higher performance in MIMO system, using interference conditions. A generic approach for both coordinated and randomized multi-user access strategies for interference mitigation is proposed. The suggestive analytical framework develops the correlation of fading channel over the space-frequency...
Massive Multi Input and Multi Output (M-MIMO) is the most prominent technology to improve the spectral and energy efficiency of future wireless systems by deploying multiple number of antennas at the base station. In this letter, we considered the impact of spatially correlation on massive MIMO downlink systems with achievable data rate in the block fading environment. The proposed schemes exploit...
The timing synchronization of OFDM/DMT systems is often based on auto-correlation algorithms. However, these algorithms do not provide a sharp correlation peak. In this work, we present a novel timing synchronization and channel estimation concept for optical block transmission systems with intensity modulation and direct detection. This concept is based on Golay complementary sequences. As these...
This paper addresses the design of MSE-optimal preambles for multicarrier channel estimation under a maximum likelihood or minimum mean squared error criterion. The derived optimality condition gives insight on how to allocate the pilots that compose the preamble. While many papers show that equispaced and equipowered allocation is optimal, the generalized condition demonstrates that there exist many...
In the context of broadband Power Line Communications (PLC), this work proposes an estimation and equalization method for block-pilot OFDM systems. The proposal is based on the correlation properties of Complementary Sequences (CS), performing all the operations in the frequency domain, which allows to reduce communication errors and the overall computational effort. The performance of the method...
In this paper, we propose a PLC synchronization method based on the correlation of PLC Preamble subcarrier in DOCSIS 3.1 Downstream system. The proposed method aims to find out the starting point of PLC Preamble OFDM symbol and to present the reference point for the allocation of pilot pattern used for channel estimation. We showed the performance of the proposed method through the maximum value detection...
In a recent paper, we have proposed a filter bank multicarrier spread spectrum (FB-MC-SS) waveform as a new method for wideband spread spectrum communications in HF bands. We have noted that FB-MC-SS is well suited for this application because of its robustness against narrow and partial band interference and because it has good performance over a wide range of delay and Doppler spreads. In this paper,...
Time-varying channel estimation is a well-known challenge for wireless communications on high-speed railways. Existing estimation algorithms include interpolation, basis expansion model (BEM) and autoregressive models. These methods remain unchanged for every scenario on high speed railways (HSRs), such as viaducts, tunnels, cutting and open areas. Thus their estimation performance are not consistent...
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