Previous
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]
Design and Simulation of Orthogonal Frequency Division Multiplexing (OFDM) Signaling
White Papers A MATLAB program has been written to investigate Orthogonal Frequency Division Multiplexing (OFDM) communication systems. Single carrier QAM and multicarrier OFDM are compared to demonstrate the strength of OFDM in multipath channels.
[January 8, 2008, 1:26]
OFDM Receiver Design
White Papers Othogonal Frequency Division Multiplex (OFDM) has gained considerable attention in recent years. In this project, authors implemented an OFDM receiver based 802.11a standard. Furthermore, since spatial diversity is the ultimate way to increase...
[October 16, 2004, 5:35]
OFDM Versus Single Carrier With Cyclic Prefix: A System-Based Comparison
White Papers Most systems rely on the use of Orthogonal Frequency Division Multiplexing (OFDM) because of its capability to elegantly cope with multi-path interference. However, while OFDM provides a nice solution for the digital modem, its front-end...
[October 16, 2004, 0:00]
OFDM for Mobile Data Communications
White Papers This paper describes Orthogonal Frequency Division Multiplexing (OFDM) and its application to mobile communications. OFDM is a modulation and multiple access technique that has been explored for over 20 years.
[September 17, 2006, 21:49]
Orthogonal Frequency Division Multiplexing (OFDM)
White Papers OFDM is a promising candidate for achieving high data rate transmission in mobile environment. The application of OFDM to high data rate mobile communication system is being investigated by many researchers.
[March 30, 2005, 3:00]
OFDM-CDMA Versus DS-CDMA: Performance Evaluation for Fading Channels
White Papers A second and rather novel technique is Orthogonal Frequency Division Multiplexing (OFDM) applying Maximum-Likelihood Detection (MLD) at the receiver. The analytical results for both DS-CDMA and OFDM-CDMA are confirmed by Monte Carlo simulations.
[February 17, 2006, 0:01]
MIMO-OFDM
White Papers OFDM is modulation method known for its capability to mitigate multipath. In OFDM the high speed data stream is divided into Nc narrowband data streams, Nc corresponding to the subcarriers or subchannels i.e.one OFDM symbol consists of N symbols...
[April 11, 2007, 1:01]
Multi-Coded OFDM Transmission Using Pace-Time Block Codes
White Papers This paper addresses link adaptation for multi-coded OFDM transmission with space-time processing. The previously proposed algorithm of Code and Modulation (CM) selection and power loading, on a basis of temporary channel information, is evaluated...
[April 11, 2007, 1:01]
PAPR Performance of IDFT-Based Uncoded OFDM Signals With Null Subcarriers and Transmit Filtering
White Papers In this paper, the Peak-to-Average Power Ratio (PAPR) is evaluated for the uncoded Orthogonal Frequency Division Multiplexing (OFDM) signals generated by using the IDFT procedure. The power spectral density of the transmitted OFDM signal is derived...
[April 11, 2007, 1:01]
The Peak Factor of a 16-QAM/OFDM System
White Papers The close relationship between the peak factor of a QPSK/OFDM system and the one from a 16-QAM/OFDM system is presented and analyzed. It is shown that a 16- QAM/OFDM system shows larger peaks and is more difficult to analyze unless use is made of...
[April 11, 2007, 1:01]
Exploiting Time Diversity to Improve Block Spread OFDM
White Papers This paper presents a new method to improve on block spread OFDM by exploiting time diversity to ensure that the blocks are independent and uncorrelated. Simulation results have shown significant improvement over conventional OFDM and Block Spread...
[April 11, 2007, 1:01]
Rate and Power Adaptation in OFDM With Quantized Feedback
White Papers Adaptive modulation can be used in conjunction with Orthogonal Frequency Division Multiplexing (OFDM) to obtain high spectral efficiencies. This paper analyzes two types of adaptive OFDM systems with quantized feedback.
[April 11, 2007, 1:01]
Design Considerations and Initial Physical Layer Performance Results for a Space Time Coded OFDM 4G Cellular Network
White Papers In this paper OFDM is proposed as a leading candidate for a 4G cellular communications standard. The key design considerations and link parameters for a 4G OFDM system are identified and initial physical layer performance results are presented for...
[April 11, 2007, 1:01]
A Software and Hardware Evaluation of Revolutionary Turbo MIMO OFDM Schemes for 5GHz WLANs
White Papers In this contribution, the performance of a newly proposed iterative MIMO-OFDM architecture is explored using MIMO channel data captured in the 5GHz band. To address this situation, this paper describes the construction of a broadband 5GHz MIMO-OFDM...
[April 11, 2007, 1:01]
Adaptive OFDM System Design for Cognitive Radio
White Papers A highly flexible OFDM system is considered to be a good candidate for the Cognitive Radio baseband processing where individual carriers can be switched off for frequencies occupied by a licensed user.
[April 11, 2007, 1:01]
The Application of Signal's Cyclostationarity in OFDM Systems
White Papers OFDM is an attractive technique for the next generation communication for its many advantages. However, there are many problems in OFDM systems, such as channel estimation and synchronization. These problems must be solved or else the OFDM system...
[April 11, 2007, 1:01]
A Blind Frequency Offset Estimator for OFDM/OQAM Systems
White Papers 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.
[April 11, 2007, 1:01]
Performance of an Adaptive Multiuser OFDM Uplink With Carrier Frequency Offsets
White Papers 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...
[April 11, 2007, 1:01]
Performance of NLOS OFDM Broadband Fixed Wireless Access Systems With Concatenated FEC Coding
White Papers The adoption of OFDM modulation combined with a powerful channel coding technique represents an attractive solution to counteract the severe NLOS channel impairments. The considered channel coding consists of concatenated Reed- Solomon and...
[April 11, 2007, 1:01]
