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othogonal frequency division multiplex

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OFDM Receiver Design: Othogonal Frequency Division Multiplex OFDM has gained considerable attention in recent years. It has been adopted for various standards include the 802.11a wireless LAN standard. In this project, authors implemented an OFDM receiver based 802.11a standard. Furthermore, since spatial diversity is the ultimate way to increase system capacity in bandwidth-cautious...; Tags: IEEE 802.11, University Of California, Othogonal Frequency Division Multiplex, Wireless LANs, OFDM, Wi-Fi, Wireless, LANs, Networking; White papers 2000-12-12

Additional Resources

Hopping Pilots for Estimation of Frequency-Offset and Multiantenna Channels in MIMO-OFDM: Orthogonal frequency-division multiplexing OFDM has been widely adopted by many standards (e.g., IEEE802.11a, IEEE802.11g in the U.S., and digital audio/video broadcasting (DAB/DVB), HiperLAN/2 in Europe), because it offers the possibility for high data rates at low decoding complexity. In this paper a pilot-symbol-assisted modulation for carrier frequency offset CFO and...; Tags: MIMO-OFDM, OFDM, Wireless; White papers 2005-01-01
Orthogonal Frequency Division Multiplexing Based on Offset QAM: One of the factors determining the performance of wireless Orthogonal Frequency Division Multiplexing OFDM systems is time-frequency localization of the transmitter and receiver pulse shaping filters. OFDM based on offset quadrature amplitude modulation (OFDM/OQAM) bypasses a major disadvantage of OFDM based on ordinary QAM, namely the fact that time-frequency well-localized...; Tags: ETH Zurich, OFDM, Wireless; White papers
MUSIC for OFDM by Using an Uniform Antenna Array With Two Elements: Multicarrier Communication MC has capability of high speed transmission, fading combating, and simplicity of equalization leading to its widely application. Among many MC applications, OFDM Orthogonal Frequency Division Multiplex is a very promising candidate. In addition, problem of DOA Direction Of Arrival estimation using MUSIC algorithm is solved for point...; Tags: Estimation, Algorithm, Music, Multicarrier Communication, OFDM, Engineering, Wireless; White papers 2005-06-16
An Interpolation-Based Frequency-Synchronization Scheme for OFDM Systems: The mismatch of the oscillators in the transmitter and receiver, or Doppler shift, introduces an offset in the expected carrier frequency. In orthogonal frequency-division multiplexing OFDM systems, this frequency offset causes large errors in the signal values and therefore it is important to minimize this offset. This paper proposes an...; Tags: Helsinki University, Offset, OFDM, Wireless; White papers 2005-04-28

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
Design and Simulation of Orthogonal Frequency Division Multiplexing (OFDM) Signaling: A MATLAB program has been written to investigate Orthogonal Frequency Division Multiplexing OFDM communication systems. This program is valuable for future researchers simulating systems that are too theoretically complex to analyze. Single carrier QAM and multicarrier OFDM are compared to demonstrate the strength of OFDM in multipath channels. Two graphical...; Tags: MATLAB Program, OFDM, Wireless; White papers 2001-05-15
An Examination of the Processing Complexity of an Adaptive Antenna System (AAS) for WiMAX: The IEEE 802.16 family of standards embrace a large number of basic and optional features. After a brief description of the key features of the IEEE 802.16 technology, this paper will focus on the adaptive antenna system AAS, which is an optional feature but one that is expected to provide...; Tags: IEEE, IEEE 802.16, WiMAX, Wireless; White papers 2005-09-01
An OFDM-TDMA/SA MAC Protocol With QoS Constraints for Broadband Wireless LANs: Orthogonal Frequency Division Multiplexing OFDM is an important technique to support high speed transmission of broadband traffic in wireless networks, especially broadband wireless Local Area Networks LANs. Based on OFDM, a new multiple access scheme, called OFDM-TDMA with subcarrier allocation (OFDMTDMA/ SA), is introduced in this paper. It provides more...; Tags: QoS, Broadband Wireless, Broadband, WLAN, OFDMA, Broadband Internet, OFDM, Network Technology, Telecommunications, LANs, Wireless, Networking; White papers
Real Time Implementation on FPGA of an OFDM Based Wireless LAN Modem Extended With Adaptive Loading: Future wireless applications target multimedia and high-speed internet access, all requiring techniques to improve the link capacity and robustness. For wireless Local Area Network LAN the standards have chosen orthogonal frequency division multiplex OFDM as modulation scheme. An extension beyond the standards to improve the link capacity is adaptive loading....; Tags: WLAN, FPGA, OFDM, LANs, Wireless LANs, Modems, Wi-Fi, Wireless, Networking, Hardware, Components; White papers
Performance of an Adaptive Multiuser OFDM Uplink With Carrier Frequency Offsets: 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 effects of carrier frequency offsets in a multiuser OFDM uplink. The paper...; Tags: Performance, Carrier Frequency Offset, Frequency Division Duplex, OFDM, Wireless; White papers
Optimal Training Signals for MIMO OFDM Channel Estimation in the Presence of Frequency Offset and Phase Noise: 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 and simulation results for the frequency-offset and PN effects on channel estimation. The proposed designs are more advantageous for moderate-to-high values of...; Tags: Frequency, Training, MIMO-OFDM, Channel Estimation, OFDM, Workforce Management, Wireless, Human Resources; White papers 2006-10-01
On Performance of SCH-OFDMA-CDM in Frequency Selective Indoor Environment: Performance of Sub Carrier Hopped Orthogonal Frequency Division Multiple Access Code Division Multiplexing (SCH-OFDMA-CDM) is analyzed and compared against its non hopping counterpart (OFDMA-CDM) in frequency selective indoor environment. The system model is developed and simulation results for realistic scenarios are presented. These provide guidelines for configuring the system and...; Tags: Performance, Environment, Scheme, Performance Management, Human Resources, Workforce Management; White papers
A Low Complexity ML Channel Estimator for OFDM: Orthogonal Frequency-Division Multiplexing OFDM with cyclic prefix enables low cost frequency-domain mitigation of multipath distortion. However, to determine the equalizer coefficients, knowledge of the channel frequency response is required. While a straightforward approach is to measure the response to a known pilot symbol sequence, existing literature reports a significant performance...; Tags: OFDM, Wireless; White papers
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
Modified SMI Techniques for Frequency Selective Channels in OFDM: The Sample Matrix Inversion SMI algorithm has been widely applied in the filed of adaptive antenna arrays. However, in Time Division Multiple Access TDMA systems with known data sequences, a low cost solution would imply the computation of the beamformer based exclusively on this data. In some cases, this might...; Tags: Sample Matrix Inversion Algorithm, OFDM, Wireless; White papers
Blind Carrier Frequency Offset Estimation in SISO, MIMO, and Multiuser OFDM Systems: Relying on a kurtosis-type criterion, a low-complexity blind carrier frequency offset CFO estimator is developed for orthogonal frequency-division multiplexing OFDM systems. The paper demonstrates analytically how identifiability and performance of this blind CFO estimator depend on the channel's frequency selectivity and the input distribution. The paper shows that this approach...; Tags: MIMO, OFDM, Wireless; White papers 2005-01-01
IEEE 802.16 Medium Access Control and Service Provisioning: This paper describes the IEEE 802.16 Orthogonal Frequency Division Multiplexing OFDM and the 802.16 Orthogonal Frequency Division Multiple Access OFDMA, Medium Access Control MAC protocols, both of which are key elements of the Worldwide Interoperability for Microwave Access Forum WiMAX deployments. The paper also discusses the types of provisioning and...; Tags: IEEE 802.16, Service Provisioning, OFDMA, WiMAX, Wireless, Wi-Fi; White papers 2004-08-20
Cross-Layer Adaptation of MPEG4 Video Streaming Over Wireless Networks Using Unequal Error Protection and MC-CDMA: A novel methodology for the efficient multiplexing and streaming of MPEG4 video over wireless networks is presented and discussed. The proposed cross-layer adaptation jointly exploits Variable-BitRate VBR Multi-Carrier Code-Division Multiplexing (MC-CDM) and MPEG4 Fine-Grain-Scalability FGS in order to provide unequal error protection to the transmitted video stream. A shared bandwidth...; Tags: Bandwidth, University Of Trento, Network, MPEG-4, Wireless Network, Digital Video, Digital Media, Wireless, Personal Technology, Consumer Electronics; White papers 2005-11-01
Joint Estimation of Channel Response, Frequency Offset, and Phase Noise in OFDM: Accurate channel estimates are needed in Orthogonal Frequency-Division Multiplexing OFDM, and easily obtained under the assumption of perfect phase and frequency synchronization. However, the practical receiver encounters nonnegligible PHase Noise PHN and Carrier Frequency Offset CFO, which create substantial intercarrier interference that a conventional OFDM channel estimator cannot account for....; Tags: OFDM, Wireless; White papers 2006-09-01

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