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Multimedia Communication Over OFDM Mobile Wireless Networks: A Cross-Layer Diversity Approach
White Papers In this work, by considering transmission of an embedded bitstream over a slow varying Rayleigh faded environment, the authors develop a cross-layer diversity technique which takes advantage of both multiple description source coding and frequency...
[April 11, 2007, 1:01]
OFDM Code-Division Multiplexing With Pre-Equalization For Mobile Communications
White Papers The code-division multiplexing (CDM) component within an orthogonal frequency-division multiplexing (OFDM) system enables additional diversity in frequency- and time-selective mobile radio channels. In this paper, the potential of orthogonal...
[October 21, 2004, 3:00]
Space-Frequency Coded MIMO-OFDM With Variable Multiplexing-Diversity Tradeoff
White Papers This paper provides a systematic method for the design of space-frequency codes with variable multiplexing-diversity tradeoffs. Space-frequency coded Orthogonal Frequency Division Multiplexing (OFDM) is capable of realizing both spatial and...
[October 26, 2004, 3:00]
A Low Complexity Antenna Diversity Receiver For OFDM Based Systems
White Papers A low complexity antenna diversity architecture with a new combining technique suitable for Orthogonal Frequency Division (OFDM) based systems is introduced in this paper. For a two branch antenna diversity, this structure requires only one FFT at...
[April 14, 2007, 1:01]
SSCH: Slotted Seeded Channel Hopping For Capacity Improvement In IEEE 802.11 Ad-Hoc Wireless Networks
White Papers This paper presents a link-layer protocol called Slotted Seeded Channel Hopping, or SSCH, that increases the capacity of an IEEE 802.11 network by utilizing frequency diversity. Capacity improvement is one of the principal challenges in wireless...
[January 11, 2006, 0:01]
Throughput Of Strongly Interfering Slow Frequency-Hopping Networks
White Papers In this paper, the throughput of devices that perform frequency hops after each transmitted packet in order to achieve diversity is investigated. With the increasing use of short-range wireless devices for high-data-rate communication in the shared...
[November 23, 2005, 0:00]
Performance Of Space-Combining Transmission Diversity With OFDM For Broadband Wireless Access Systems
White Papers This paper proposes a new diversity technique for broadband wireless access systems that uses orthogonal frequency division multiplexing (OFDM) and describes its performance. This technique consists of two components.
[October 21, 2004, 5:37]
Subspace-Based Blind Channel Estimation For OFDM By Exploiting Virtual Carriers
White Papers Several options exist in practical OFDM systems - including training symbols, cyclic prefix, virtual carriers, pilot tones, and receiver diversity - to facilitate channel estimation. Reliable channel estimation is indispensable for orthogonal...
[October 21, 2004, 3:00]
Increasing Data Rates Through Iterative Coding And Antenna Diversity In OFDM-Based Wireless Communication
White Papers Transmitter diversity and coding techniques can be used in high date-rate wireless communications with Orthogonal Frequency Division Multiplexing (OFDM) to improve the performance. To compensate for the performance loss associated with an extended...
[April 18, 2007, 1:00]
Joint Dynamic Detection And Channel Estimation In MIMO OFDM Systems
White Papers In this paper, a MIMO OFDM system is developed, which employ interleaver at the transmitter to implement frequency domain diversity. Transmitter diversity and channel estimation play important roles in improving the system performance.
[September 17, 2007, 2:08]
Algorithms For Quantized Precoded MIMO-OFDM Systems
White Papers The knowledge of the wireless channel is crucial for realizing the capacity and diversity gains of a MIMO system. In this paper, OFDM is considered as an implementation of linearly precoded MIMO spatial multiplexing systems over frequency selective...
[April 11, 2007, 1:01]
Performance Analysis Of Bit-Interleaved Space-Time Coding For OFDM In Block Fading Channels
White Papers Performance analyses based on both pairwise error probability (PEP) and error bounds are conducted over a more general block fading channel that possesses both frequency and time diversity, and of which the fast and quasi-static fading channels...
[November 2, 2004, 2:00]
Space-Time-Frequency Transmit Diversity In Broadband Wireless OFDM Systems
White Papers This paper considers space-time -frequency transmits diversity with orthogonal designs in a broadband OFDM system. Particularly, the paper discusses orthogonal transmit diversity versus spatial multiplexing and space-time-frequency codes which have...
[April 14, 2007, 1:01]
Spatial Transmit Diversity Techniques For Broadband OFDM Systems
White Papers This paper investigates different spatial transmit diversity concepts for orthogonal frequency division multiplexing (OFDM) systems. The achievable performance gains with the proposed transmit diversity concepts are presented for convolutionally...
[March 30, 2005, 3:00]
Achieving High-Capacity Wireless By Merging Multicarrier CDMA Systems And Oscillating-Beam Smart Antenna Arrays
White Papers The MC-CDMA component supports high performance (in a probability-of-error sense) via frequency diversity and high network capacity via code division. The smart antenna with oscillating-beam pattern further enhances performance via transmit...
[August 3, 2004, 3:00]
OFDM Code Division Multiplexing With Unequal Error Protection And Flexible Data Rate Adaptation
White Papers This combination enables a robust transmission with flexible error protection and data rate adaptation for parallel data streams by exploiting additional diversity due to CDM. In this paper, an OFDM-CDM (Orthogonal Frequency Division Multiplexing...
[February 17, 2006, 0:01]
Transmit Diversity Vs Beamforming For Multi-User OFDM Systems
White Papers 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 OFDM (OFDM-TDMA and OFDMA) systems.
[April 18, 2007, 1:00]
Spatial Multiplexing And Diversity Gain In OFDM-Based MIMO Systems
White Papers This paper investigates trade offs between different techniques in broadband OFDM-based MIMO systems for achieving full diversity or maximum spatial multiplexing gain. The basic model of OFDM-based spatial multiplexer is very suitable for high data...
[October 21, 2004, 5:45]
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]
Interpolation Based Transmit Beamforming For MIMO-OFDM With Limited Feedback
White Papers Transmit beamforming and receive combining are simple methods for exploiting spatial diversity in Multiple-Input Multiple-Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) system. This paper proposes to a limited feedback architecture...
[April 11, 2007, 1:01]
