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Frequency Domain DFE: System Design And Comparison With OFDM
White Papers A novel frequency domain equalizer for single carrier modulation is presented. It performs as a decision feedback equalizer (DFE) with the feedforward operating in the frequency domain, and a feedback filtering in time domain.
[October 21, 2004, 0:00]
Frequency Allocations For WiMAX Systems In Hong Kong
White Papers This paper gives a technical overview of WiMAX ("Worldwide Interoperability for Microwave Access") systems and explores the possible available frequency bands for WiMAX application in Hong Kong. WiMAX is a non-profit corporation formed by equipment...
[January 16, 2005, 23:00]
Direct Sequence Vs. Frequency Hopping
White Papers As infrared is a limited technology that is only capable of transmitting relatively short distance vs.radio-based methods, in this document we will explore the two RF options, known as Direct Sequence Spread Spectrum (DSSS) and Frequency Hopping...
[November 13, 2003, 23:00]
Frequency Domain Down-Conversion Of HDTV Using Adaptive Motion Compensation
White Papers We present a novel frequency synthesis algorithm, which constructs a set of 8x8 DCT coefficients from four original 8x8 DCT blocks. The purpose of this paper is to investigate the possible means of down converting an incoming HDTV signal into one...
[September 21, 2004, 0:00]
Frequency Assignment For Multi-Cell IEEE 802.11 Wireless Networks
White Papers Due to the coupling between the physical and MAC layers, conventional frequency planning and allocation methods for typical cellular networks cannot be applied directly to the 802.11 network. The IEEE 802.11 standard specifies both radio and MAC...
[October 20, 2005, 0:00]
Frequency-Domain Interference Cancellation For MIMO-OFDM Systems
White Papers This paper proposes a new interference cancellation scheme for multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) systems in the presence of intersymbol interference (ISI).
[October 31, 2004, 23:00]
A Frequency-Domain Double-Talk Detector Based On Normalized Cross-Correlation Vector
White Papers This paper presents a frequency-domain calculation scheme for the normalized cross-correlation DTD. Furthermore, assuming that the adaptive algorithm of the echo canceler is a frequency-domain formulation, the complexity of the DTD is low since...
[April 6, 2005, 0:00]
Performance Of Space-Frequency Techniques Over Measured Channels In MIMO-OFDM Systems
White Papers This paper examines the performance of some recently proposed Space-time coding and signal processing techniques when applied to Orthogonal Frequency Division Multiplexing (OFDM) in Multiple Input Multiple Output (MIMO) configuration.
[April 11, 2007, 0:00]
Optimal Placement Of Training For Frequency-Selective Block-Fading Channels
White Papers The problem of placing training symbols optimally for orthogonal frequency-division multiplexing (OFDM) and single-carrier systems is considered. For OFDM systems, it is shown that the lower bound is maximized by placing the known symbols...
[October 26, 2004, 0:00]
Maximum-Likelihood Carrier Frequency Offset Estimation For OFDM Systems In Fading Channels
White Papers Carrier Frequency Offset (CFO) is a major contributor to the inter-carrier - interference in OFDM systems. This paper presents two maximum-likelihood CFO estimation schemes, one in frequency domain and another in time-domain, both under Doppler...
[April 13, 2007, 0:00]
On The Comparison Between OFDM And Single Carrier Modulation With A DFE Using A Frequency-Domain Feedforward Filter
White Papers Most comparisons between single carrier and multi-carrier modulations assume frequency-domain linear equalization of the channel. This paper proposes a new frequency-domain decision feedback equalizer (FD-DFE) for single carrier modulation, which...
[November 1, 2004, 23:00]
A Combined Timing And Frequency Synchronization And Channel Estimation For OFDM
White Papers This paper addresses training signal based combined timing and frequency synchronization and channel estimation for OFDM systems. At the first stage, coarse timing and frequency offset estimates are obtained.
[April 13, 2007, 0:00]
A Reduced Complexity, Improved Frequency Offset Estimation For OFDM-Based WLANs
White Papers This paper presents a reduced complexity frequency offset estimation method as a modification to the nonlinear least square (NLS) method. The complexity reduction is achieved by utilizing the Chirp-Z transform.
[April 13, 2007, 0:00]
Full Duplex OFDM Modem Over A Frequency Selective Channel
White Papers This paper discusses the design and implementation of a DSP-based OFDM modem for full duplex communication between two PCs over a frequency selective channel. The paper considers the features that make OFDM (OFDM is acronym for Orthogonal Frequency...
[October 26, 2004, 0:00]
Adaptive Zero-Padding OFDM Over Frequency-Selective Multipath Channels
White Papers This paper presents a novel bandwidth (BW) efficient orthogonal frequency division multiplexing (OFDM) scheme with adaptive zero-padding (AZP-OFDM) for wireless transmission. Redundancy issues in OFDM based on cyclic prefix (CP), zero-padding (ZP...
[October 26, 2004, 0:00]
Impact Of The Propagation Environment On The Performance Of Space-Frequency Coded MIMO-OFDM
White Papers Previous work on space-frequency coded MIMOOFDM has been restricted to idealistic propagation conditions. In this paper, using a broadband MIMO channel model taking into account Ricean K-factor, transmit and receive angle spread, and antenna...
[October 26, 2004, 0:00]
Diversity Analysis Of Space-Time-Frequency Coded Broadband OFDM Systems
White Papers This paper proposes a general framework for the performance analysis of space-time-frequency coded MIMO-OFDM systems. The approach presented in this paper incorporates the space-time and space-frequency coding approaches as special cases.
[March 30, 2005, 0:00]
Optimal Training Signals For MIMO OFDM Channel Estimation In The Presence Of Frequency Offset And Phase Noise
White Papers 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...
[April 13, 2007, 0:00]
Space-Frequency Coded MIMO-OFDM With Variable Multiplexing-Diversity Tradeoff
White Papers Space-frequency coded Orthogonal Frequency Division Multiplexing (OFDM) is capable of realizing both spatial and frequency-diversity gains in multipath multiple-input multiple-output (MIMO) fading channels.
[October 26, 2004, 0:00]
Compatibility Of Bluetooth With Other Existing And Proposed Radiocommunication Systems In The 2.45 GHz Frequency Band
White Papers The spectrum needs of Short Range Devices (SRD) are most often allocated into an ISM band on a frequency-sharing basis (non-interference, non-protection basis) and the industry has the advantage of a general license type approval.
[November 10, 2005, 23:00]
