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Space-Frequency Coded MIMO-OFDM With Variable Multiplexing-Diversity Tradeoff
White Papers This naturally leads to the question of variable allocation of the channel's degrees of freedom to multiplexing and diversity transmission modes. Space-frequency coded Orthogonal Frequency Division Multiplexing (OFDM) is capable of realizing both...
[October 26, 2004, 3:00]
On Cyclic Delay Diversity In OFDM Based Transmission Schemes
White Papers Cyclic Delay Diversity (CDD) is a simple approach to introduce spatial diversity to an Orthogonal Frequency Division Multiplexing (OFDM) based transmission scheme that itself has no built-in diversity.
[March 25, 2008, 7:41]
Adaptive Modulation For Variable-Rate OFDM Systems With Imperfect Channel Information
White Papers Adaptive modulation has been shown to have significant benefits for high-speed wireless data transmission when orthogonal frequency division multiplexing (OFDM) is employed. However, accurate channel state information (CSI) is required at the...
[July 21, 2005, 6:00]
Efficient Power Allocation For Coded OFDM Systems
White Papers Orthogonal Frequency Division Multiplexing (OFDM) is a transmission technique which divides the data into a number of independent frequency subchannels whose bandwidth is much less than the total data rate.
[April 11, 2007, 1:01]
PAPR Reduction Using Integer Structures In OFDM Systems
White Papers Orthogonal Frequency Division Multiplexing (OFDM) is a multicarrier transmission technique, which is widely adopted in different communication applications. OFDM prevents Inter Symbol Interference (ISI) by inserting a guard interval and mitigates...
[October 28, 2004, 3:00]
Throughput Comparison Of CDM And TDM For Downlink Packet Transmission In CDMA Systems With A Limited Data Rate Set
White Papers Throughputs with Code-Division Multiplexing (CDM) and Time-Division Multiplexing (TDM) for downlink packet transmission are compared in multirate Code-Division Multiple Access (CDMA) systems. The authors propose and use a model that can show the...
[February 22, 2006, 0:01]
Adaptive Air Interface Schemes For MAGNET Based On OFDM-TDMA Transmission
White Papers A transmission system employing orthogonal frequency-division multiplexing (OFDM) with bit-interleaved coded modulation (BICM) and perfect channel state information (CSI) at both transmitter and receiver is considered in this paper.
[March 30, 2005, 3:00]
Spatial Multiplexing And Diversity Gain In OFDM-Based MIMO Systems
White Papers Multiple transmit and receive antennas can be used with orthogonal frequency division multiplexing to improve performance and transmission rate. The basic model of OFDM-based spatial multiplexer is very suitable for high data rate transmission, and...
[October 21, 2004, 5:45]
The Power Line Transmission Characteristics For An OFDM Signal
White Papers This paper measures what influence the sinusoidal transmission characteristics of the electric power line with various forms gave to the transmission characteristic of OFDM (Orthogonal Frequency Division Multiplexing) signal through PLC (Power...
[April 11, 2007, 1:01]
Performance Of Clustered OFDM With Low Density Parity Check Codes Over Dispersive Channels
White Papers The main advantage of orthogonal frequency division multiplexing (OFDM) is that it allows transmission over frequency selective channels with a low receiver implementation complexity. This paper presents a new LDPC coded clustered OFDM system with...
[November 2, 2004, 2:00]
Turbo Coding Performance In OFDM Packet Transmission
White Papers In transmission of the packets using OFDM (Orthogonal Frequency Division Multiplexing) system recommended by IEEE.802.11 there is a constraint on the interleaving depth due to the maximum allowable packet size and processing delay requirement.
[October 26, 2004, 3:00]
OFDM Based WLAN Systems
White Papers Orthogonal Frequency Division Multiplexing (OFDM) is a special form of multi-carrier transmission where all the subcarriers are orthogonal to each other. OFDM promises a higher user data rate and great resilience to severe signal fading effects of...
[April 18, 2007, 1:00]
Bandwidth And Power Efficiency Considerations For Optimal Training In OFDM
White Papers Orthogonal Frequency Division Multiplexing (OFDM) has been adopted by many high speed transmission standards. Pilot Tone Assisted Modulation (PTAM) is a well known technique to estimate the Channel State Information (CSI) in OFDM but is not...
[August 7, 2008, 1:18]
OFDM Or Single-Carrier Block Transmissions?
White Papers 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).
[October 21, 2004, 6:56]
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, 3:00]
Broadband MIMO-OFDM Wireless Communications
White Papers Orthogonal frequency division multiplexing (OFDM) is a popular method for high data rate wireless transmission. OFDM may be combined with antenna arrays at the transmitter and receiver to increase the diversity gain and/or to enhance the system...
[November 2, 2004, 2:00]
A Generic Transmission Scheme For Fourth Generation Wireless Systems
White Papers This paper proposes a generic transmission scheme that allows to instantiate all the combinations of orthogonal Frequency-Division Multiplexing (OFDM) and cyclic-prefixed Single-Carrier (SC) modulations with Time-Division Multiple Access (TDMA...
[January 20, 2006, 0:01]
Performance Analysis And Design Optimization Of LDPC-Coded MIMO OFDM Systems
White Papers This paper considers the performance analysis and design optimization of Low-Density Parity Check (LDPC) coded Multiple-Input Multiple-Output (MIMO) Orthogonal Frequency-Division Multiplexing (OFDM) systems for high data rate wireless transmission.
[April 26, 2007, 1:00]
A Novel OFDM Transmission Scheme With Length-Adaptive Cyclic Prefix
White Papers A novel Orthogonal Frequency Division Multiplexing (OFDM) transmission scheme is proposed in this paper to adapt the CP length to the variation of channel delay spread. Conventional OFDM transmission system uses a fixed-length Cyclic Prefix to...
[November 2, 2004, 2:00]
OFDM Code Division Multiplexing With Unequal Error Protection And Flexible Data Rate Adaptation
White Papers In this paper, an OFDM-CDM (Orthogonal Frequency Division Multiplexing Code Division Multiplexing) system with adaptive symbol mapping is presented. This combination enables a robust transmission with flexible error protection and data rate...
[February 17, 2006, 0:01]
