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In wireless communication, Ricean K factor which is the relative strength of the direct and scattered components of the received signal, is an important reflection of channel quality parameters. Therefore, the estimate of Ricean factor is great significance. Based on the introduction of the estimation methods of K from envelope and from the I/Q components, there is an academic analysis about the precision...
LMMSE algorithm is one of the best linear channel estimations for time domain synchronous orthogonal frequency division multiplexing (TDS-OFDM) system. The research on the computational complexity reduction of LMMSE algorithm remains to be a challenging topic. Since the combination of fast Fourier transform with singular value decomposition (FFT-SVD) simplify the channel autocorrelation matrix computation...
In this paper, we propose an analytical eye-diagram estimation method for a channel of a pair of differential microstrip traces on PCBs with arbitrary source and load terminations. The closed-form equation of the voltage transfer function for the given channel structure is derived and the method to deduce the worst case data patterns by considering the asymmetric and finite slew rates of the input...
Tree-based Gibbs sampling (proposed by Hamze and de Freitas) is used to compute a Monte-Carlo estimate of the partition function of factor graphs with cycles. The proposed method can be used, in particular, to compute the capacity of noiseless constrained 2-D channels.
In the DFT-spread-OFDM system, the traditional frequency estimation scheme can accurately estimate half of channel frequency responses (on the odd-indexed sub-carriers) and yet the other half (on the even-indexed sub-carriers) can only be made out of approximation or interpolation. It is because that the long block used for data-transmission is double length of short block used for channel estimation...
Precise indoor positioning is becoming increasingly important in commercial, military and public service applications for tracking people and asset. Ultra Wide Band (UWB) can provide high accuracy position with strong anti-jamming and low power consumption. It is very suitable for indoor positioning application. This paper will put emphasis on indoor positioning system based on UWB.Analysis and implementation...
This paper proposes a low-complexity equalizer for orthogonal frequency division multiplexing (OFDM) systems under time-varying frequency-selective fading environments. The equalization uses suboptimum maximum likelihood sequence estimation (MLSE) in cooperation with semi-blind linear prediction (SBLP) in the estimation of the channel frequency responses. When the number of pilot subcarriers is far...
In an autonomous sensor network without a central fusion center, it is desired that any node has the ability to make the final decision once it has enough information about the phenomenon of interest (PoI) within a certain confidence level. In this paper, we propose a distributed sequential methodology which updates the current node's estimator based on its own observation and noise corrupted decision...
In contrast to the conventional Viterbi algorithm (VA) which generates hard-outputs, an optimum soft-output Viterbi algorithm (SOVA) is derived under the constraint of fixed decision delay for detection of digital signals in the presence of intersymbol interference and additive white Gaussian noise. The SOVA, a new type of the conventional symbol-by-symbol maximum a posteriori probability algorithm,...
We present an accurate SER estimation method for low duty, QPSK modulated, Direct Sequence Impulse Radio (DS-IR) over a frequency selective channel with RAKE reception. The approach is a useful novelty since the existing SER estimation methods for DS-IR are problematic in the low duty case because they are accurate only when the number of pulses per symbol is high. The approach is exploited to study...
Precise indoor positioning is becoming increasingly important in commercial, military and public service applications for tracking people and asset. Ultra Wide Band (UWB) can provide high accuracy position with strong anti-jamming and low power consumption. By combining orthogonal frequency-division multiplexing (OFDM) with multi-band, MB-OFDM systems can capture multi-path energy more efficiently...
The signal transmitted is often added by white noise in the transmission channel of the communication system. That may result in the distortion of the signal and induce the difficulty of the signal demodulation at the receiving end. Comparing to the traditional estimation method which relies on amount of prior knowledge, a novel method of amplitude estimation of signal white noise based on EMD algorithm...
A novel algorithm for effective channel order estimation, NECOE, is proposed in this paper, which exploits the relation of the channel order and a special matrix constructed by ldquonoiserdquo subspace, and derives a new theorem about the special matrix. Based on the new theorem, the novel algorithm estimates the channel order by modifying the dimension of ldquonoiserdquo subspace. Simulations prove...
Cyclic Prefix (CP) based block Recursive Least Squares (RLS) channel estimation algorithms have been proposed for Orthogonal Frequency Division Multiplexing (OFDM) systems. In this paper, we investigate the performance of CP based exponentially weighted block RLS channel estimator. Our analysis and extensive simulation results show that smaller values of exponential forgetting weightings cause increase...
In this paper we study the impact of the overlapping between neighboring MPCs (multipath component) on the performance of channel estimation. We consider IR-UWB (impulse radio) signals, and the IEEE802.15.3a and IEEE802.15.4a UWB channel models. We show that for a pulse width (PW) sufficiently smaller than the average MPC rate of arrival (ROA) the probability to have more than three overlapping MPCs...
In this paper, we consider the problem of estimating the physical parameters that describe a multipath MIMO communication channel model characterized by specular reflections due to remote scatterers. Using the impulse response channel coefficients, we introduce a channel model based on a 3rd-order tensor structure that admits a Parafac decomposition with rank equal to the number of propagation paths...
An uplink OFDMA systems is considered. Different users use different transmit antennas, thus, each user contributes a different carrier frequency offset (CFO) at the receiver. The multiple CFOs introduce intercarrier interference, thus impeding user separation and transmit signal recovery. A low complexity CFO estimation approach is proposed for estimating multiple CFOs. The proposed approach relies...
We combine the characteristics of the Super Exponential (SE) method with Logic Strings and Second Order Statistics (SOS) to blindly estimate a multipath channel. The estimator benefits from the good quality of estimation inherent of SOS methods to estimate the magnitude of a channel's transfer function allied to the fact that the SE can estimate the channel phase response, and that Logic String estimator...
We analyze the outage for distributed estimation over orthogonal fading channels as a function of the number of sensors, K. We consider a scenario of fixed power per-sensor with an asymptotically large number of sensors. We characterize the scaling law of the outage and show that the outage decays faster than exponentially in the number of sensors and slower than exp(-K log K).
In the paper, we propose a conditionally biased linear estimator to estimate a deterministic vector h subjected to a linear transformation M and corrupted by zero-mean additive white Gaussian noise, w. We begin by drawing inspiration from the rank shaping idea of the Rank Shaped Least Squares (RSLS) estimator. We then incorporate the estimator into the Covariance Shaping Least Squares (CSLS) framework,...
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