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As the number of indoor location based services increase in the mobile market, service providers demanding more accurate indoor positioning information. To improve the location estimation accuracy, this paper presents an enhanced client centered location prediction scheme and filtering algorithm based on IEEE 802.11 ac standard for indoor positioning system. We proposed error minimization filtering...
As a promising technique to meet the drastically growing demand for both high throughput and uniform coverage in the fifth generation (5G) wireless networks, massive multiple-input multiple-output (MIMO) systems have attracted significant attention in recent years. However, in massive MIMO systems, as the density of mobile users (MUs) increases, conventional uplink training methods will incur prohibitively...
The main object of this study is to quantify the effect of botulinum toxin on the dynamic ankle impedance (ZAnkle) in children with cerebral palsy (CP). The effect was evaluated by comparing the ZAnkle before and one month later the botulinum injection in gastrocnemius muscle. A cohort of six children with CP was involved in the study. All data were gathered by the pediatric version of the Anklebot...
A novel concept of orthogonal frequency division multiplexing (OFDM) multiple input multiple output (MIMO) radar for automotive applications is presented in this paper. Multiple transmit antennas are multiplexed via OFDM subcarrier interleaving. Such a multiplexing enables a simultaneous operation of transmit antennas, while the complete bandwidth is utilized by each of them. Whereas the known OFDM-MIMO...
The channel estimate and carrier frequency offset (CFO) acquisition are two essential bases for multiple-inputmultiple-output (MIMO) and orthogonal frequency division multiplexing (OFDM) techniques. In high-mobility scenario, the fast time varying channel and the serious Doppler frequency shift will make the channel tracking and CFO estimation much more challenging. In this paper, the achievable limits...
We address the problem of channel estimation in a large multiple-input multiple-output (MIMO) system using pilot symbol aided algorithm in Rayleigh fading environment. Conventional minimum mean square error and minimum variance unbiased based channel estimators require the inversion of covariance matrices, which has computational complexity of the order of N^6, where N is the number of antennas at...
The efficient and highly accurate channel state information at the base station is essential to achieve the potential benefits of massive multiple input multiple output-orthogonal frequency division multiplexing (MIMO-OFDM) systems, due to limitation of the pilot contamination problem. In this paper, we investigate the whitening rotation (WR) semi-blind channel estimation algorithm for multi-cell...
Multiple-input multiple-output (MIMO) systems constitute an important part of todays wireless communication standards and these systems are expected to take a fundamental role in both the access and backhaul sides of the emerging wireless cellular networks. Recently, reported measurement campaigns have established that various outdoor radio propagation environments exhibit sparsely structured channel...
The knowledge of CSI at the BS (CSIT) is required to achieve the high spectrum efficiency promised by massive MIMO. In Frequency-Division Duplex (FDD) Massive MIMO systems, the CSIT is obtained via downlink channel estimation and uplink channel feedback, However, the acquisition of CSIT is a very challenging problem in practical FDD massive MIMO systems with a large number of antennas. Recently, compressive...
Acquisition of accurate channel state information (CSI) at the base station (CSIT) is a major challenge of deploying frequency-division duplexing (FDD) massive MIMO systems. Although compressive sensing (CS) based CSIT estimation approaches have been proposed to reduce the pilot training overhead for massive MIMO systems, the existing schemes cannot properly dimension the minimum required pilot symbols...
Massive MIMO enables the improvement on the transmission rate without increasing the burden on the signal processing by employing a large number of antennas at a base station (BS). Channel state information (CSI) feedback scheme from terminal stations to BS gives a very large overhead when considering massive MIMO and implicit beamforming (IBF) with the calibration technique as the countermeasures...
Ambient noise not only influences the data transmission but also causes incorrect CSI. To overcome the low SNR problem, traditional methods usually retransmit the same packet for enough times to increase the SNR. Unfortunately, recently works only focus on the failed data retransmission, yet totally overlook the incorrect channel estimation, which are not efficient for multi-user MIMO WLAN. As long...
In this paper, we propose a joint soft iterative detection scheme utilizing expectation maximization (EM) and low density parity check (LDPC) codes for multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems. A soft iterative MIMO detector is introduced, by exploiting soft-input soft-output in the detection and decoding, the tractable extrinsic information efficiently...
In this paper, an approach of Estimating Signal Parameter via Rotational Invariance Techniques (ESPRIT) under sensor gain-phase uncertainties errors is reprensented with the Direction Of Arrival (DOA) and the Direction Of Departure (DOD) is considered. The approximate expressions for the Root Mean Square Error (RMSE) of the ESPRIT DOA and DOD estimation under random sensor perturbations are derived...
To ensure reliable communication and improve performance of a wireless communication system, it is required for the transmitter and receiver to have fair knowledge about the channel state information (CSI). Analysis of the basic channel prediction schemes like Parametric Radio channel model, Autoregressive model based prediction and Bandlimited basis expansion is done in this paper. Subspace based...
With very high carrier frequencies (such as millimeter-wave (mmW) bands), a very large number of antennas can be packed at the base station (BS). For this kind of high dimensional channel, it is desirable to exploit signal directions to estimate the channel directions. In this paper, we analyze the performance of the direction of arrival (DoA) estimation based on unitary ESPRIT algorithm assuming...
Recent results have revealed that massive multiple-input-multiple-output (MIMO) channels exhibit a sparse structure. In this paper, we leverage this feature into the development of a novel channel estimation algorithm, namely, the Adaptive-Least Absolute Shrinkage and Selection Operator (A-LASSO), in which the sparsifying matrix (dictionary) and the sparse vector are jointly optimized. The key ingredients...
We consider the problem of direction of arrival (DOA) estimation in multiple-input multiple-output (MIMO) radar taking into account a possibility that some sensors are broken. In this case, the DOA estimation suffers from performance degradation. Motivated by the fact that the MIMO structure and difference co-array (MIMO-DC) processing can be used jointly and it comes with an advantage that the virtual...
We address the problem of pilot decontamination for massive MIMO systems for finite dimensional channels, wherein the channel vectors between the users and the base station are composed of a finite number of discrete paths. The pilot decontamination problem is addressed using high-resolution parametric spectral estimation methods, such as root multiple-signal classification (root-MUSIC), for resolving...
This paper presents the methods which are based on delta operator for identification and control of MIMO systems where time moments are used. Delta time moments (DTM) are computed from real time input-output data and are utilized to develop adaptive predictive algorithms in a model reference framework. The reference model is developed in the complex delta domain from classical time and frequency domain...
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