Sponsored White Papers, Webcasts, and Downloads
Additional Resources
- A Simple Scalable Space-Frequency Coding Scheme for MIMO-OFDM
- There are several space-time and space-frequency coding schemes proposed in the literature for MIMO-OFDM. This paper presents a linear space-frequency coding scheme based on permutation matrices, that is scalable with number of antennas and spatial-multiplexing SM rate, and is easy to implement. Furthermore, the design allows for low cost power...
- Tags: Marvell, MIMO-OFDM
- White papers 2004-10-15
- Noncoherent Space-Frequency Coded MIMO-OFDM
- Recently, the use of coherent space-frequency coding in orthogonal frequency division multiplexing OFDM-based frequency-selective multiple-input multiple-output MIMO antenna fading channels has been proposed. Acquiring knowledge of the fading coefficients in a MIMO channel is already very challenging in the frequency-flat fast fading case. In the frequency-selective case, this task becomes...
- Tags: Channel, MIMO, IEEE, MIMO-OFDM, OFDM, Wireless
- White papers 2005-02-14
- Impact of the Propagation Environment on the Performance of Space-Frequency Coded MIMO-OFDM
- 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 spacing, we study the impact of the propagation environment on the performance of space-frequency coded MIMO-OFDM.
- Tags: ETH Zurich, Performance, Environment, MIMO-OFDM, Performance Management, Human Resources, Workforce Management
- White papers
- Space-Frequency Bit-Interleaved Coded Modulation for MIMO-OFDM/OFDMA Systems
- This paper proposes space-frequency bit-interleaved coded modulation (SF-BICM), which provides both frequency diversity and spatial diversity by interleaving coded bits across transmit antennas and frequency tones. Performance of the proposed SF-BICM is compared to spatial multiplexing (F-BICM) using 802.16e-like coding and modulation over ITU channel models. Performance is demonstrated with...
- Tags: Performance, IEEE, Modulation, Performance Management, Human Resources, Workforce Management
- White papers 2004-11-04
- Space-Frequency Coded Broadband OFDM Systems
- Space-time coding for fading channels is a communication technique that realizes the diversity benefits of multiple transmit antennas. Previous work in this area has focused on the narrowband flat fading case where spatial diversity only in available. This paper investigates the use of space-coding in OFDM-based broadband systems where both...
- Tags: Stanford University, Broadband, OFDM, Broadband Internet, Network Technology, Telecommunications, Wireless, Networking
- White papers
- Diversity Analysis for Frequency-Selective MIMO-OFDM Systems With General Spatial and Temporal Correlation Model
- In this paper, the effect of a general spatial and temporal fading correlation structure on the performance of coded MIMO-OFDM systems is studied. The analysis handles an arbitrary joint transmit-receive spatial correlation model including the non-Kronecker model. An upper bound on the maximum achievable diversity order for frequency-selective MIMO-OFDM systems...
- Tags: Diversity, MIMO-OFDM, Analysis
- White papers 2005-08-09
- A Space-Time Block-Coded OFDM Scheme for Unknown Frequency-Selective Fading Channels
- This paper introduces a space-time block-coded orthogonal frequency-division multiplexing (STBC-OFDM) scheme for frequency-selective fading channels, which does not require channel knowledge either at the transmitter or at the receiver. The decoding algorithm is based on generalized maximum-likelihood sequence estimation. Due to the assumed orthogonality structure of STBC, the decoding rule...
- Tags: University Of Texas, OFDM, Engineering, Wireless
- White papers
- Bit Interleaved Coded Modulation With Space Time Block Codes for OFDM Systems
- Wireless systems often implement one or more types of diversity in order to achieve reliable communication. Different types of diversity techniques such as temporal, frequency, code, and spatial have been developed in the literature. In addition to the destructive multipath nature of wireless channels, frequency selective channels pose InterSymbol Interference...
- Tags: Channel, OFDM, Wi-Fi, Wireless
- White papers 2006-04-05
- Bluetooth Operation
- The networking standards of Bluetooth will transmit data via low power radio frequency. Bluetooth communicates on a 2.45 GHz frequency. This very band of frequency has been set aside by international agreement for the use of industrial and medical devices. Many devices that one already known and use take advantage...
- Tags: Frequency, Bluetooth, Wi-Fi, Wireless
- White papers
- Bit and Power Allocation for MIMO-OFDM Systems With Spatial Mode Selection Over Frequency- Space- Time- Selective Channels
- Multiple input multiple output orthogonal frequency division multiplexing (MIMO-OFDM) system is known to reduce the negative impact of the time dispersive characteristic of channels and show high spectral efficiency. Various spatial modes, such as multiplexing and diversity, can be used to improve the spectral efficiency further. This paper proposes the...
- Tags: Seoul National University, Allocation, MIMO-OFDM
- White papers 2004-10-04
- Transmit Diversity Vs Beamforming for Multi-User OFDM Systems
- In an Orthogonal Frequency Division Multiplexing OFDM system, downlink beamforming can be implemented either before IDFT frequency domain or after IDFT time domain module in a base station transmitter. This paper compares Pre-IDFT downlink beamforming with Space-Time Block coded and Space-Frequency block coded transmit diversity schemes for 4×1 downlink multi-user...
- Tags: Cell, OFDM, Wireless
- White papers 2004-07-02
- Frequency Counter (zip)
- Frequency Counter is an easy to use utility to assist with classical cryptanalysis. It takes a text file, up to 2G, and computes the frequency of characters A-Z. Results are displayed numerically and graphically. Great for students of cryptology.
- Tags: Frequency, Frequency Counter, Cellular Phones, Consumer Electronics, Personal Technology
- Software downloads 2005-09-14
- LDPC Based Differential Unitary Space-Frequency Coding for MIMO-OFDM Systems
- This paper proposes a novel LDPC based differential unitary space-frequency coding DUSFC scheme for MIMO-OFDM systems when neither the transmitter nor the receiver has access to the channel state information CSI. The new DUSFC strategy basically consists of coding across transmit antennas and OFDM tones simultaneously as well as differential...
- Tags: Zhejiang University, MIMO-OFDM, OFDM, Wireless
- White papers 2004-09-21
- Differential Modulation Diversity for OFDM
- The application of Differential Modulation Diversity DMD to orthogonal frequency division multiplexing with multiple transmit and/or receive antennas is considered. Based on diagonal signals originally designed for differential space-time modulation, DMD is used to exploit both space and frequency diversity. At the receiver, low-complexity decision-feedback differential detection without channel state...
- Tags: University Of Toronto, OFDM, Wireless
- White papers
- Joint Time-Domain Tracking of Channel and Frequency Offset for OFDM Systems
- This paper addresses the problem of joint channel and frequency offset estimation and tracking for OFDM systems. The proposed method is based on Extended Kalman filtering. The channel taps and the frequency offset are estimated in time-domain while equalization is performed in frequency domain. Simulation results demonstrate accurate tracking capability...
- Tags: Frequency, Channel, Method, OFDM, Wireless
- White papers 2006-03-21
- Slow Subcarrier-Hopped Space Division Multiple Access OFDM Systems
- Space Division Multiple Access SDMA assisted Multi-Input-Multi-Output MIMO OFDM systems invoking Multi-User Detection MUD techniques have attracted substantial research interests, which are capable of exploiting both transmitter multiplexing gain and receiver diversity gain. Furthermore, the classic Frequency-Hopping FH technique can be effectively amalgamated with SDMA-OFDM systems, resulting in Frequency-Hopped FH...
- Tags: Technique, Microsoft Access, Diversity, OFDM, Productivity, Wireless
- White papers 2005-03-18
- A Space-Time Receiver for MIMO-OFDM Ad Hoc Networks
- This paper proposes a receiver architecture that can demodulate multiple data streams with different frequency offsets and propagation delays in Multiple Input Multiple Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) ad hoc networks. The receiver performs joint synchronization and interference cancellation to separate these interfering data streams and achieve synchronization for...
- Tags: Frequency, University Of Texas, MIMO-OFDM, Receiver, OFDM, Wireless
- White papers 2006-03-01
- Concatenated RS-Convolutional Codes for Ultrawideband Multiband-OFDM
- This paper investigates the performance of concatenated Reed Solomon and convolutional RSconvolutional codes for UltraWideBand UWB MultiBand Orthogonal Frequency Division Multiplexing (MB-OFDM) systems. This paper show that RS-convolutional codes perform better than single codes at high energy-per-bit to noise ratio (Eb/No). The paper also show that using a bit interleaver...
- Tags: UWB, University Of Oxford, Ultrawideband (UWB), Wireless
- White papers 2006-07-09
- 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
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