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.
Generation of the signal and noise subspaces is a critical problem in subspace-based algorithms for orthogonal frequency division multiplexing (OFDM) systems. Some special characteristics, such as virtual carriers (VCs), real symbols, and/or cyclic prefix (CP), can be exploited to construct the required noise subspace in conventional subspace approaches. In this paper, a blind channel estimation algorithm...
While the use of geostationary satellites allows tactical radios users to achieve beyond the line-of-sight communications nearly anywhere within the footprint of a satellite system, the use of directional antennas forces the radio operator to know the precise location of the satellite that is being used. Though a pointing guide and compass can work reasonably well when positioning an antenna, the...
The optimal source precoding matrix and relay amplifying matrix have been developed in recent works on multiple-input multiple-output (MIMO) relay communication systems assuming that the instantaneous channel state information (CSI) is available. However, in practical relay communication systems, the instantaneous CSI is unknown, and therefore, has to be estimated at the destination node. In this...
Time Division-Synchronous Code Division Multiple Access (TD-SCDMA) has several attractive characteristics that made it capable of meeting the requirements of G4 systems when applied as a platform directly. Joint detections, the unpaired spectrums with flexible sharing of resources, and some other advanced properties leads TD-SCDMA to achieve high data rate services. In this paper a comprehensive analysis...
This paper proposes a new scheme of the rate compatible low-density parity-check (RC-LDPC) coded single carrier-frequency domain equalization (SC-FDE) system where RC-LDPC codes are combined with SC-FDE modulations. To construct a class of different RC-LDPC codes, we take advantage of a base matrix constructed by the progressive edge growth (PEG) algorithm. A special code matrix structure is used...
Channel Estimation (CE) is one of the key technologies in mobile communication system and also important in Sounding Reference Signal (SRS) that is used to detected channel quality information in LTE uplink. According to the latest LTE specification, the pilot aided CE algorithms for LTE uplink are researched in this paper. To improve the performance and decrease the complexity of traditional channel...
The inverse-filtering of acoustic impulse responses (AIRs) can be achieved with existing methods provided a good estimate of the channel is available and the observed signals contain little or no noise. Such assumptions are not generally valid in practical scenarios, leading to much interest in the issue of robustness. In particular, channel shortening (CS) techniques have been shown to be more robust...
A detection algorithm based on dual-sliding-window (DSW) is designed for the detection of channel impulse response (CIR). In OFDM systems with coherent demodulation, the precision of channel estimation has a significant impact on the performance of the receivers. However, traditional threshold-detection algorithms adopted by time-domain channel estimation are sensitive to noise in the presence of...
This paper presents an innovative technique that identifies the most significant paths of the multipath channels based on the Last Mean Square (LMS) and Normalized Least Mean Squares (NLMS) algorithms applied to RAKE receiver. Simulations have been carried out for a DS-CDMA signal with QPSK modulation, and the performances have been evaluated in terms of the number of taps detected as a function of...
We propose and assess a pilot-data aided channel estimation scheme for realistic relay-assisted scenarios designed for the downlink SFBC OFDM-based systems. We consider that both the base station and the relay node are equipped with an antenna array whereas the user terminal is a single antenna device. The relay protocol considered is equalise-and-forward. The channel estimation method iteratively...
In this paper, the DS-UWB channel estimation and multiuser detection problem are investigated. The information symbol and channel parameter are considered as unknown variable. The multiuser detector and UWB channel estimator are designed jointly. For symbol detection, the one-step predictor of channel parameter is used and the estimation error is treated as a multiplicative noise, then a Riccati equation...
A novel method based on particle filter has been proposed for Rayleigh channel state estimate and tracking in this paper. After receiving a symbol, the particles approximate the channel state at a higher temperature and a sequential resampling is taken to generate the initial particles for the lower temperature particle filter . With this simulated annealing scheme, the particle filter conquers degeneration...
In this paper, an H-infinity channel estimator, adopting simplified objective function, is introduced to multiple-input multiple-output with orthogonal frequency division multiplexing (MIMO-OFDM) systems. Next, the matrices inversions and multiplications are reduced by using the expectation maximum (EM) algorithm. Finally, the performance degradation due to the carrier frequency offset (CFO)) is improved...
Single-carrier frequency domain equalization (SC-FDE) has been standardized as an alternative of orthogonal frequency division multiplexing (OFDM) in IEEE 802.11ad and 802.15.3c. In addition, with the use of low density parity-check (LDPC) codes, multi-Giga bits transmission can be supported in 60-GHz millimeter-wave (mmW) WLAN/WPAN with desired decoding complexity. In this paper, we present and evaluate...
A diversity scheme with Fractional Sampling (FS) in OFDM receivers has been investigated recently. In the previous literature it has been shown that performance improvement with path diversity through FS depends on the bandwidth of the total channel response including transmit and receive baseband filters. However, if the signal on the adjacent channel exists, that signal causes interference to the...
Orthogonal Frequency Division Multiplexing (OFDM) technique serves as an important architecture for very high data rate short range wireless communication systems from Ultra-Wideband (UWB) to 60GHz millimeter wave systems for Wireless Personal Area Networks (WPANs). One of the bottleneck in implementing these high data rate systems is the demanding requirement for high-speed and high-precision Analog-to-Digital...
In this work we propose and evaluate a pilot and data-based channel estimation scheme for SFBC OFDM-based cooperative scenario. We consider that both the base station and the relay node are equipped with double antenna arrays whereas the user terminal is a single antenna device. The relay protocol considered is equalise-and- forward. In this paper we propose a channel estimation method that iteratively...
The interference rejection combining (IRC) receiver is effective in improving the cell-edge user throughput because it suppresses inter-cell interference. The IRC receiver is typically based on the minimum mean square error (MMSE) criteria, which requires channel estimation and covariance matrix estimation including the inter-cell interference with high accuracy. The paper investigates the gain from...
Coherent receivers are derived for a pilot-symbol aided distributed Alamouti-coded system with imperfect channel state information. The derived coherent receivers do not perform channel estimation but rather use the received pilot signals for decoding. The derived receiver metrics use the statistics of the channel to give improved performance. The performance is further improved by using the decision...
New generation of satellite navigation signals, such as AltBOC (Alternative Binary Offset Keying), CBOC (Composite Binary Offset Keying) and TMBOC (Time Multiplex Binary Offset Keying) bring enhancements in the tracking process, such as more signal power, better multipath mitigation capabilities and more robust navigation. Moreover, one of the most important improvement they bring into the GNSS story...
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.