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- Experimental Studies on a OFDM Carrier Frequency Offset Estimator
- In OFDM carrier frequency offset must be estimated and compensated at the receiver to maintain orthogonality. OFDM carrier frequency synchronization performance can be improved by using diversity. This paper examines the sensitivity of the carrier frequency estimator against key system parameters in a practical implementation using real data obtained on...
- Tags: OFDM, Wireless
- White papers
- Performance of an Adaptive Multiuser OFDM Uplink With Carrier Frequency Offsets
- Using an OFDM based uplink for the future cellular network has been controversial issue due to difficulties in time and frequency synchronization and high Peak-to-Average Power Ratio PAPR. In this paper, a model is provided to quantify the effects of carrier frequency offsets in a multiuser OFDM uplink. The paper...
- Tags: Performance, Carrier Frequency Offset, Frequency Division Duplex, OFDM, Wireless
- White papers
- A Blind Frequency Offset Estimator for OFDM/OQAM Systems
- Like other OFDM-like systems, OFDM/OQAM systems are very sensitive to carrier frequency offset. A new blind carrier frequency estimator is introduced herein for OFDM- /OQAM systems by exploiting the non-circularity of the received signal. Since the received signal exhibits conjugate cyclic frequencies at twice the carrier frequency offset, a frequency...
- Tags: Frequency, Texas A&M University, OFDM, Wireless
- White papers
- An Interpolation-Based Frequency-Synchronization Scheme for OFDM Systems
- The mismatch of the oscillators in the transmitter and receiver, or Doppler shift, introduces an offset in the expected carrier frequency. In orthogonal frequency-division multiplexing OFDM systems, this frequency offset causes large errors in the signal values and therefore it is important to minimize this offset. This paper proposes an...
- Tags: Helsinki University, Offset, OFDM, Wireless
- White papers 2005-04-28
- OFDM or Single-Carrier Block Transmissions?
- This paper compares two block transmission systems over frequency-selective fading channels: orthogonal frequency-division multiplexing OFDM versus single-carrier modulated blocks with zero padding ZP. It first compares their peak-to-average power ratio PAR and the corresponding power amplifier backoff for phase-shift keying or quadrature amplitude modulation. Then it studies the effects of...
- Tags: Channel, University Of Minnesota, OFDM, Wireless
- White papers 2004-03-01
- Blind Carrier Frequency Offset Estimation in SISO, MIMO, and Multiuser OFDM Systems
- Relying on a kurtosis-type criterion, a low-complexity blind carrier frequency offset CFO estimator is developed for orthogonal frequency-division multiplexing OFDM systems. The paper demonstrates analytically how identifiability and performance of this blind CFO estimator depend on the channel's frequency selectivity and the input distribution. The paper shows that this approach...
- Tags: MIMO, OFDM, Wireless
- White papers 2005-01-01
- Maximum-Likelihood Carrier Frequency Offset Estimation for OFDM Systems in Fading Channels
- Carrier Frequency Offset CFO is a major contributor to the inter-carrier - interference in OFDM systems. This effect becomes more sever when compounded by the presence of Doppler fading in wireless channels. This paper presents two maximum-likelihood CFO estimation schemes, one in frequency domain and another in time-domain, both under...
- Tags: Carrier Frequency Offset, OFDM, Wi-Fi, Wireless
- White papers 2006-03-09
- Design of Robust Pulses to Carrier Frequency Offset for OFDM/OQAM System
- The high sensitivity to carrier frequency offset of OFDM systems compared to single carrier systems is well known. This paper studies how this can be remedied for OFDM/OQAM systems by appropriate pulse shaping. Building on earlier methods for minimizing out-of-band energy, a procedure for pulse shape design is derived. The...
- Tags: Pulse, OFDM, Wireless
- White papers 2005-07-12
- Estimation of Carrier-Frequency Offset and Frequency-Selective Channels in MIMO OFDM Systems Using a Common Training Signal
- This paper presents a common training signal design and corresponding estimation methods for carrier frequency offset and frequency-selective channels in MIMO OFDM systems. In designing the common training signal, a training signal structure which yields low complexity estimation methods is developed while the optimality of the training signal is maintained....
- Tags: Estimation, Training, MIMO-OFDM, Estimation Method, Workforce Management, Human Resources
- White papers 2004-09-13
- Cooperative STBC-OFDM Transmissions With Imperfect Synchronization in Time and Frequency
- This paper studies the cooperative STBC-OFDM transmissions when the cooperative transmitters are not perfectly synchronized in time and carrier frequency. While OFDM can effectively resolve the limited delay asynchronism among the transmitters, the asynchronism in carrier frequency presents a major hurdle. Based on an approximate channel model, the paper analyzes...
- Tags: Transmitter, Transmission, OFDM, Wireless
- White papers 2005-11-25
- Behavioral Model of UHF RFID Tag for System and Application Level Simulation
- This paper presents a model of an UHF RFID tag for system and application level simulation. The prime focus is on the radio frequency link. The model describes carrier frequency dependent behavior based on the envelope signal description with the value of the carrier frequency being time invariant parameter. The...
- Tags: IEEE, Background Idea, ASICs, Semiconductors, Hardware
- White papers 2005-10-23
- Blind Estimation of the Carrier Frequency Offset in OFDM Systems
- This paper presents a novel approach for carrier frequency offset estimation in OFDM systems. Before they enter the OFDM system, the information bearing symbols are segmented into blocks so that each even indexed block shares one common symbol with the previous block. This redundancy allows for the frequency offset estimation...
- Tags: Estimation, OFDM, Wireless
- White papers
- Hopping Pilots for Estimation of Frequency-Offset and Multiantenna Channels in MIMO-OFDM
- Orthogonal frequency-division multiplexing OFDM has been widely adopted by many standards (e.g., IEEE802.11a, IEEE802.11g in the U.S., and digital audio/video broadcasting (DAB/DVB), HiperLAN/2 in Europe), because it offers the possibility for high data rates at low decoding complexity. In this paper a pilot-symbol-assisted modulation for carrier frequency offset CFO and...
- Tags: MIMO-OFDM, OFDM, Wireless
- White papers 2005-01-01
- Spectral Efficiency of Multicarrier CDMA
- This paper analyzes the spectral efficiency (sum-rate per sub-carrier) of randomly spread synchronous multi-carrier code-division multiple access (MC-CDMA) subject to frequency-selective fading in the asymptotic regime of number of users and bandwidth going to infinity with a constant ratio. Both uplink and downlink are considered, either conditioned on the sub-carrier...
- Tags: CDMA, IEEE, Cellular Phones, Consumer Electronics, Personal Technology
- White papers 2005-02-01
- On Performance of SCH-OFDMA-CDM in Frequency Selective Indoor Environment
- Performance of Sub Carrier Hopped Orthogonal Frequency Division Multiple Access Code Division Multiplexing (SCH-OFDMA-CDM) is analyzed and compared against its non hopping counterpart (OFDMA-CDM) in frequency selective indoor environment. The system model is developed and simulation results for realistic scenarios are presented. These provide guidelines for configuring the system and...
- Tags: Performance, Environment, Scheme, Performance Management, Human Resources, Workforce Management
- White papers
- Pilot-Tone Based ZP-OFDM Demodulation for an Underwater Acoustic Channel
- Existing coherent underwater acoustic communication systems rely on single carrier transmission and adaptive decision feedback equalization to deal with time-varying and highly dispersive UnderWater Acoustic UWA channels. Equalization complexity prevents any substantial rate improvement with the existing single-carrier approach, as the channel frequency selectivity increases considerably when the symbol rate...
- Tags: Channel, Equalization Complexity, OFDM, Wireless
- White papers 2006-07-26
- Training Sequence Vs. Cyclic Prefix: A New Look on Single Carrier Communication
- This paper introduces a new Training-Aided Single Carrier TASC scheme taking advantage of the Cyclic Prefix nature of a short Training Sequence TS. This allows to perform frequency domain equalization, like for the Single Carrier with Cyclic Prefix (CP-SC) scheme. The modification of the CP in a TS allows to...
- Tags: Training, Workforce Management, Human Resources
- White papers
- Joint Estimation of Channel Response, Frequency Offset, and Phase Noise in OFDM
- Accurate channel estimates are needed in Orthogonal Frequency-Division Multiplexing OFDM, and easily obtained under the assumption of perfect phase and frequency synchronization. However, the practical receiver encounters nonnegligible PHase Noise PHN and Carrier Frequency Offset CFO, which create substantial intercarrier interference that a conventional OFDM channel estimator cannot account for....
- Tags: OFDM, Wireless
- White papers 2006-09-01
- abuot Crrier
- can anbody help me to give answer of my Question.If i want to build my Carrier in IT Field what Should i do means I have Completed Just B.Com Bechlor Of Commerce.Can i Doing Any Certification Course that is enough to raise my Carrier Without MCA Degree.plz help me on...
- Tags: pratik_bhade@...
- Discussion threads 2007-02-07
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