The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
A novel approach for blind channel equalizer design which uses channel zero information is presented in the paper. The second order statistics of the received signal is combined with the information of a single slice of fourth order cumulants to efficiently identify a finite impulse response (FIR) channel with the use of a very small number of data samples. It is shown how the estimated FIR channel...
Motivated by the desirable attributes of both Alamouti-type space-time (ST) codes and constant envelope modulations, we introduce in this paper an ST minimum-shift keying (MSK) transmission scheme and the companion receiver. Taking advantage of the block-wise differential encoding on which the MSK transmission is based, the receiver performs noncoherent sequence detection on a down-sampled subset...
All existing training signal designs for channel estimation in OFDM systems neglect phase noise or both frequency offsets and phase noise. In practice, frequency offset and phase noise are unavoidable and can seriously degrade the performance of OFDM systems. In this paper, we address the problem of designing optimal training signals for the estimation of frequency-selective channels in MIMO OFDM...
This study presents multiband ultra-wideband (UWB) communication system with IEEE 802.15.3a standard, which utilizes multicarrier transmission with orthogonal frequency-division multiplexing (OFDM) technology. In this paper, based on a statistical autoregressive (AR) channel model in the frequency domain, we proposed an algorithm that can adaptively track the channel time-variation which is subject...
In this paper, a new channel estimation approach is proposed for ultra-wideband (UWB) communication systems. Performance of UWB systems employing RAKE receivers highly depends on the channel knowledge. Because UWB systems operate in dense multipath environments, channel estimation task becomes more complicated. Some channel estimation methods have been proposed for UWB systems. Here a very simple...
For multiple-input multiple-output (MIMO) antenna systems, if perfect channel state information (CSI) is available at the transmitter and receiver sides, advanced beamforming (ABF) can be applied at both sides so that the transmitted data streams can be decoupled easily, and adaptive modulation can be utilized to maximize the throughput. When the available CSI is imperfect, however, the data streams...
Adaptive modulation can approach the channel capacity by adapting the number of bits per transmission symbol to channel quality variations. This paper proposes a fixed threshold adaptive modulation scheme for orthogonal frequency division multiplexing (OFDM) used in power line communications. This adaptive OFDM is combined with an adaptive power control scheme in order to combat with multipath fading...
In this paper, a class of unitary transform based optimal pilots is found for time domain channel estimation in multiple input multiple output (MIMO) orthogonal frequency division multiplexing (OFDM) systems. Also, a frequency domain channel estimation which does not need interpolation is obtained. It is shown that the frequency domain method achieves the same performance as the time domain method...
This paper is a study of an iterative joint algorithm for frequency offset and time offset synchronizations used in 256 orthogonal frequency division multiplexing of IEEE 802.16d wireless-MAN system. As deployed in an urban area and targeted at providing a high data rate transmission, IEEE 802.16d system requires a robust synchronization mechanism to guarantee the transmission reliability. A time-domain...
An improved channel estimator with time delay tracking measurement for OFDM systems is proposed by exploiting the inherent correlation between the cyclic prefix and port of the received OFDM signal. This scheme make use of real time measured size of inter-symbol interference (ISI) free window to estimate the maximum delay spread of channel, then a transform domain channel estimator is adopted to further...
Pilot symbol assisted modulation (PSAM) is a practical technique to maintain high performance in mobile communications. Based on received pilot symbols, frequency offset can be estimated and compensated accordingly. One important class of estimators is based on the maximum likelihood (ML) criterion. The ML-based estimator has high computational complexity, which is typically of the order of O(N2)...
The space-time coded code-division multiple-access (ST-coded CDMA) has been widely investigated for the great demand of capacities and transmission rates in the future wireless communication systems. The blind Capon multiuser receiver was designed to achieve the goal by the linearly constrained minimum variance (LCMV) filter. However, the LCMV filter suffers the effects of finite samples and signature...
Recently, the space-time coded code division multiple access (ST-coded CDMA) has been widely investigated for the great demand on capacities and transmission rates in the future wireless communication systems. The Alamouti's space-time block code scheme is examined here where two linearly constrained minimum variance (LCMV) filters are designed in the receiver. In this paper, the two weight vectors...
Superimposed training has raised lots of attentions due to its great spectral efficiency and its relatively fast channel estimation algorithms. In this paper, we present channel estimation methods for OFDM system using periodic superimposed training added in frequency domain. At the receiver, channel estimation is done both in time domain (pre-FFT) and frequency domain (post-FFT). We can see the pre-FFT...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.