Serwis Infona wykorzystuje pliki cookies (ciasteczka). Są to wartości tekstowe, zapamiętywane przez przeglądarkę na urządzeniu użytkownika. Nasz serwis ma dostęp do tych wartości oraz wykorzystuje je do zapamiętania danych dotyczących użytkownika, takich jak np. ustawienia (typu widok ekranu, wybór języka interfejsu), zapamiętanie zalogowania. Korzystanie z serwisu Infona oznacza zgodę na zapis informacji i ich wykorzystanie dla celów korzytania z serwisu. Więcej informacji można znaleźć w Polityce prywatności oraz Regulaminie serwisu. Zamknięcie tego okienka potwierdza zapoznanie się z informacją o plikach cookies, akceptację polityki prywatności i regulaminu oraz sposobu wykorzystywania plików cookies w serwisie. Możesz zmienić ustawienia obsługi cookies w swojej przeglądarce.
Ultra-wideband(UWB) radio has gained a major breakthrough in wireless communications. However, the sampling is a huge obstacle to it. Applying compressed sensing(CS) principle which can recover a sparse signal from less measurement to UWB communication has been a hot topic for many years. This paper shows two methods to construct the CS model for UWB communication, jointing the signal reconstruction...
This paper presents a novel application of adaptive modulation and coding (AMC) for spacecraft communication systems. Whereas terrestrial AMC often assumes availability of either real-time or statistical channel state information at the transmitter (CSIT), in the space environment there are often insufficient resources to provide real-time access to channel statistics at the transmitter. We demonstrate...
In this paper, energy detectors are developed for wideband and ultra-wideband (UWB) pulse position modulation (PPM). Exact bit error probability (BEP) formulas are derived under different assumptions about the channel. More specifically, we present an expression for the instantaneous BEP for a specific channel realization, as well as an expression for the average BEP for a channel with independent...
In time of arrival (TOA) estimation of received ultra-wideband (UWB) pulses, traditional maximum likelihood (ML) and generalized likelihood estimators become impractical due to their high sampling rate. Sub-nyquist ML-based TOA estimation currently assumes a priori knowledge of the UWB channels in the form of the average power delay profile (APDP). In this paper, instead of assuming a known APDP,...
In UWB communication system, to guarantee reliability and validity, receiver must know the characteristic of channel. Based on the difference and similarity between Rayleigh fading channel and UWB channel, we propose a modified channel estimation algorithm for MB-OFDM system considering complexity of cluster structure in UWB channel. Moreover, we make a parallel comparison of LS and MMSE algorithms...
New channel estimation technique is proposed for multiband orthogonal frequency division multiplexing (MB-OFDM) ultra-wideband (UWB) systems. Several steps have been carried out to achieve this purpose. In first step, refined least square (LS) channel estimation is found out by using subspace-based narrowband interference (NBI) estimation method with prilimonary LS channel. In second step, low rank...
Recently, multi-symbol based transmitted reference system has drawn attention for UWB communications because of its high performance without estimating the channel explicitly. The maximum-likelihood (ML) detector for multi-symbol transmitted reference system has been proposed to jointly detect the multi-symbol and yields a considerable improvement compared with conventional single symbol detector...
In this paper we present a low-complexity iterative algorithm to estimate the Time of Arrival (ToA) of an Impulse-Radio Ultra Wide Band (IR-UWB) system with pulse overlap between the first two paths. The performance of this SAGE estimation algorithm is compared with that of the optimal estimator. We find that, although the SAGE algorithm is unable to determine a tight ToA estimate when the delay between...
In this paper, we investigate the analog front-end imperfection in multi-band orthogonal frequency division multiplexing (MB-OFDM) ultra-wideband (UWB) systems and propose a joint estimation and compensation scheme. The estimation of CFO and SFO is presented on frequency domain, which is robust to frequency dependent I/Q imbalance. After that, I/Q imbalance and channel response is jointly estimated...
We show that the common approach to channel and Time-of-Arrival (ToA) estimation for Impulse-Radio Ultra WideBand (IR-UWB), where the occurrence of pulse overlap is ignored, is bound to lead to considerable estimation errors in the presence of pulse overlap. We propose the use of a low-complexity extension of the sliding correlator as a Maximum Likelihood (ML) channel estimation method that can deal...
The Impulse Radio - Ultra Wideband (IR-UWB) technology, which benefits from unprecedented ranging capabilities through precise Time of Arrival (TOA) estimation, is now widely considered as a credible solution for Location and Tracking (LT) applications in Wireless Sensor Networks (WSN). In this context, low-complexity receiver architectures such as Energy Detectors (ED) have been favored for the past...
This paper presents a novel study of ultra wideband communication over household powerlines in a very high frequency band, from 50 MHz to 550 MHz. Adaptive modulation has been exploited on the Multiband-OFDM model for UWB over PLC system, the aim is to improve the system's data transmission error rate. By means of simulations, we compare the performance of adaptive and non-adaptive modulation over...
We present a fast converging scheme for estimating the coarse frequency offset in multi-band orthogonal frequency division multiplexing (MB-OFDM) based ultra-wideband (UWB) systems. Our estimator performs an averaging of initial estimate over multiple bands and shows an improved estimation of =3 times for band group 1 compared to our earlier proposed scheme. Cramer Rao lower bound (CRLB) on the estimation...
In this paper, we propose a novel signal to noise ratio algorithm based on the moments of the received signal. The novel algorithm has been designed for multi band orthogonal frequency division multiplexing (MB-OFDM) communication systems in ultra wide band channels. The proposed algorithm is a switched estimator that uses two equation models, one is for large SNR scale and the other for low SNR scale...
This paper proposes a maximum eigenvector based weighted non-coherent receiver (MEV-WNCR) for impulse radio ultra-wideband (IR-UWB) systems with pulse position modulation (PPM). Capitalizing on the SNR maximization criterion, we derive the optimal combining weights for the MEV-WNCR as the maximum eigenvector of the received signal sample covariance matrix. Unlike the conventional WNCR, the a priori...
We propose an efficient common phase error (CPE) mitigation scheme for orthogonal frequency division multiplexing (OFDM) based ultra-wideband (UWB) systems. We consider the phase errors resulting from both residual carrier frequency offset and random phase noise. The CPE estimator employs a pilot-tone based and channel frequency response weighted approach for achieving low-complexity intra-OFDM-symbol...
We consider the problem of ranging with Impulse Radio (IR) Ultra-WideBand (UWB) radio under weak Line Of Sight (LOS) environments and additive Gaussian noise. We use a Bayesian approach where the prior distribution of the channel follows the IEEE 802.15.4a channel model, to estimate the joint posterior probability density function (pdf) of the channel and the targeted distance. One of applications...
Novel non-data-aided maximum likelihood estimators for the delays and the attenuations in an ultra-wide bandwidth channel are proposed. Numerical results show that these new estimators outperform the previous non-data-aided maximum likelihood channel estimators derived in the literature. Moreover, in some cases, the performances of the new non-data-aided estimators approach those of the data-aided...
In this paper, we propose a novel noncoherent UWB (de)modulation system, which uses a pair of orthogonal pulses to convey information symbols. Same as the original noncoherent UWB, our approach remains operational even without timing and channel estimation. Moreover, due to the orthogonality between the received waveforms of the pulse pair, our approach results in a differential demodulator. This...
A novel signal structure is designed for a high data rate (HDR) Prerake UWB system, which uses orthogonal codes and chip-interleaving to suppress the inter-chip interference (ICI). On one hand, high data rate is achieved via superposition of symbols. On the other hand, the symbols are coded using the Walsh-Hadamard codes and interleaved on the chip level, which largely eliminates the ICI. The BER...
Podaj zakres dat dla filtrowania wyświetlonych wyników. Możesz podać datę początkową, końcową lub obie daty. Daty możesz wpisać ręcznie lub wybrać za pomocą kalendarza.