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- Totally Blind Channel Estimation for OFDM on Fast Varying Mobile Radio Channels
- A new blind channel estimation scheme for OFDM-systems is proposed based on the ML-principle. By avoiding the use of second- and higher-order statistics, a very fast convergence rate is achieved. A novel approach is also proposed for resolving the phase ambiguity of the blind channel estimate without the need for...
- Tags: Georgia Institute Of Technology, Performance, Mobile, Radio, Ambiguity, Channel Estimation, OFDM, Advertising & Promotion, Wireless, Marketing
- White papers
- Generalized 8-PSK for Totally Blind Channel Estimation in OFDM
- Channel estimation in OFDM systems can conveniently be done by inserting a stream of pilot symbols at the transmitter and by using FIR interpolation filters at the receiver. Most blind channel estimation approaches are based on higher order statistics and converge slowly, making them unsuitable for mobile environments. Moreover, the...
- Tags: Channel Estimation, OFDM, Wireless
- White papers
- Temporal Diversity Assisted Blind Channel Estimation for Downlink Long-Code CDMA Systems
- In CDMA downlink, subspace channel estimation can not be applied directly since long spreading codes destroy the rank condition of the received data covariance matrix. However, after introducing temporal diversity in the transmitted chip sequence for all users, subspace technique can be applied to estimate channel. Detection of the desired...
- Tags: University Of California, Channel Estimation, Productivity, Performance Management, Cellular Phones, Human Resources, Workforce Management, Consumer Electronics, Personal Technology
- White papers
- Channel Estimation for D-BLAST OFDM Systems
- Diagonal Bell Laboratories Layered Space-Time DBLAST structure offers a low complexity solution to realize the attractive capacity of Multiple-Input And Multiple-Output MIMO systems. This paper applies D-BLAST in Orthogonal Frequency Division Multiplexing OFDM systems and addresses the issue of channel estimation. Different from other MIMO-OFDM, where symbols at all tones...
- Tags: Channel Estimation, OFDM, Wireless
- White papers
- Totally Blind APP Channel Estimation for Mobile OFDM Systems
- A new two-dimensional blind channel estimation scheme for coherent detection of OFDM signals in a mobile environment is presented. The channel estimation is based on the A Posteriori Probability APP calculation algorithm. The time-variant channel transfer function is completely recovered without phase ambiguity with no need for any pilot or...
- Tags: Mobile, Channel Estimation, Phase Ambiguity Problem, OFDM, Advertising & Promotion, Wireless, Marketing
- White papers
- Channel Estimation Techniques for OFDM Systems
- Channel estimation is an important and necessary function for modern wireless receivers. With even a limited knowledge of the wireless channel properties, a receiver can gain insight into the information that was sent by the transmitter. The goal of channel estimation is to measure the effects of the channel on...
- Tags: Technique, Channel Estimation, OFDM, Wi-Fi, Wireless
- White papers 2007-03-01
- Optimal Training Signals for MIMO OFDM Channel Estimation in the Presence of Frequency Offset and Phase Noise
- The authors develop robust Mean-Square Error MSE-optimal training signal designs for multiple-input multiple-output orthogonal frequency-division multiplexing channel estimation with frequency offset and Phase Noise PN, and present analytical and simulation results for the frequency-offset and PN effects on channel estimation. The proposed designs are more advantageous for moderate-to-high values of...
- Tags: Frequency, Training, MIMO-OFDM, Channel Estimation, OFDM, Workforce Management, Wireless, Human Resources
- White papers 2006-10-01
- Optimal Superimposed Pilot Selection for OFDM Channel Estimation
- This paper presents an optimal strategy for utilizing superimposed pilots for OFDM channel estimation using Wiener filtering. An algorithm is formulated to determine the optimal rectangular set of time-frequency samples for channel estimation for a given complexity. The proposed scheme shows an improved performance at high Doppler frequencies. Moreover, the...
- Tags: Algorithm, Performance, Channel Estimation, OFDM, Performance Management, Productivity, Wireless, Human Resources, Workforce Management
- White papers 2006-04-19
- A Reduced Complexity Channel Estimation for OFDM Systems With Precoding and Transmit Diversity in Mobile Wireless Channels
- A precoding approach for reduced complexity channel estimation for OFDM systems with transmit diversity is presented. Two different OFDM schemes that employ the precoding are investigated: the first one is based on space-time coding, the second is based on a transmit diversity using an optimal design of symbols for channel...
- Tags: Mobile, Diversity, Channel Estimation, OFDM, Wireless
- White papers 2006-02-07
- A Combined Timing and Frequency Synchronization and Channel Estimation for OFDM
- This paper addresses training signal based combined timing and frequency synchronization and channel estimation for OFDM systems. The proposed scheme consists of two stages. At the first stage, coarse timing and frequency offset estimates are obtained. Based on these estimates, a coarse channel response estimate is obtained. The timing and...
- Tags: IEEE, Channel Estimation, OFDM, Wireless
- White papers 2005-08-30
- Pilot-Symbol-Aided Iterative Channel Estimation for OFDM-Based Systems
- This paper proposes a pilot-symbol-aided iterative channel estimation for coded OFDM-based systems. The authors use the symbol APP provided by the channel decoder to form groups of virtual pilots. According to their reliabilities, the authors combine these groups to improve the channel estimation. The paper also compares the proposed algorithm...
- Tags: Channel Estimation, OFDM, Engineering, Wireless
- White papers 2005-08-16
- Improving Channel Estimation in OFDM Systems for Sparse Multipath Channels
- This paper describes an algorithm for sparse channel estimation applicable to orthogonal frequency division multiplexing systems. The proposed algorithm uses a least squares LS technique for channel estimation and a generalized Akaike information criterion to estimate the channel length and tap positions. This effectively reduces the signal space of the...
- Tags: Algorithm, Indian Institute Of Technology, Channel Estimation, OFDM, Engineering, Wireless
- White papers 2005-01-01
- Pilot-to-Data Power Ratio for Maximizing the Capacity of MIMO-OFDM
- Orthogonal frequency division multiplexing OFDM can be used with a multiple-input multiple-output MIMO system to improve communication quality and capacity. Pilot-symbol-aided or decision-directed channel estimation must be used to track the variations of the channel. However, while pilot symbols facilitate channel estimation, they reduce the transmit energy for data symbols...
- Tags: MIMO-OFDM, Channel Estimation, OFDM, Wireless
- White papers 2004-11-22
- Optimal Training Signals for SISO OFDM Channel Estimation in the Absence/Presence of Frequency Offsets
- All existing training signal designs for channel estimation in OFDM systems assume no frequency offsets. In practice, frequency offset is unavoidable and seriously degrades the performance of OFDM systems. This paper addresses the problem of designing optimal training signals for SISO OFDM channel estimation in the presence of frequency offsets....
- Tags: Training, Channel Estimation, Frequency Offset, OFDM, Workforce Management, Wireless, Human Resources
- White papers 2004-09-13
Additional Resources
- Channel Estimation for OFDM Systems in Case of Insufficient Guard Interval Length
- This paper presents a novel method used to channel estimation for OFDM systems in case of insufficient guard interval length. This method suppresses additive noise and interference components by averaging the estimated channel coefficients in the time direction. The channel coefficients obtained after time averaging must be added to an...
- Tags: Coefficient, OFDM, Wireless
- White papers
- Joint Channel Estimation and Prediction for OFDM Systems
- Adaptive OFDM improves the system throughput by adjusting transmission parameters based on Channel State Information CSI estimated at or received by the transmitter. The improvement, however, is conditioned on the quality of the CSI, which can be compromised by estimation and quantization errors, and more significantly by delay. Channel prediction...
- Tags: Estimation, Algorithm, University Of Texas, Adaptive OFDM, Channel Prediction, OFDM, Wi-Fi, Engineering, Wireless
- White papers 2005-08-01
- Combined Frequency and Time Domain Channel Estimation in Mobile MIMO-OFDM Systems
- This paper proposes a combined frequency and time domain channel estimation method for MIMO OFDM systems. Initial channel estimation is performed by first estimating the channel response in frequency domain, exploiting a set of dedicated pilot carriers, followed by an interpolation step. In order to reduce the interpolation error and...
- Tags: Mobile, Domain, IEEE
- White papers 2006-04-19
- Estimation of Frequency Selectivity for OFDM Based New Generation Wireless Communication Systems
- In this paper, estimation of both global long term and local instantaneous frequency selectivity and rms delay spread of wireless communication channel are investigated. A practical algorithm for averaged channel frequency correlation estimation, which is used for measuring frequency selectivity, is given. Average rms delay spread of the channel is...
- Tags: Estimation, Wireless Communication, Frequency Selectivity, Wi-Fi, Wireless, OFDM
- White papers
- Low-Complexity Channel Estimation for Transmitter Diversity OFDM Systems
- Orthogonal Frequency Division Multiplexing OFDM has recently been proposed for achieving high-bit rate communication required in wireless systems. Transmitter diversity can be used with OFDM system for performance improvement in a fading environment. For these systems the receiver requires channel state information for decoding. This paper proposes a novel low...
- Tags: Transmitter, OFDM, Wireless
- White papers
- Doppler Spread Estimation for Wireless OFDM Systems
- This paper presents a method for estimating the Doppler spread in mobile Orthogonal Frequency Division Multiplexing OFDM systems. The estimation is based on finding the autocorrelation function of time domain channel estimates over several OFDM symbols. In OFDM systems channel estimation is popularly performed in frequency domain. Channel frequency response...
- Tags: Estimation, Estimate, OFDM, Wireless
- White papers
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