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Topic: OFDMA


In the News (Tue 14 Feb 12)

  
  OFDMA - Wikipedia, the free encyclopedia
OFDMA resembles code division multiple access (CDMA) spread spectrum, where users can achieve different data rate by assigning different code spreading factor or different number of spreading codes to each user.
OFDMA can also be seen as an alternative to combining OFDM with time division multiple access (TDMA) or time-domain statistical multiplexing, i.e.
OFDMA is used in the mobility mode of IEEE 802.16 WirelessMAN Air Interface standard, commonly referred to as WiMAX.
en.wikipedia.org /wiki/OFDMA   (554 words)

  
 Orthogonal frequency-division multiplexing - Wikipedia, the free encyclopedia
In Orthogonal Frequency Division Multiple Access (OFDMA), frequency-division multiple access is achieved by assigning different OFDM sub-channels to different users.
OFDMA supports differentiated quality-of-service by assigning different number of sub-carriers to different users in a similar fashion as in CDMA, and thus complex packet scheduling or media access control schemes can be avoided.
OFDMA is used in the uplink of the IEEE 802.16 Wireless MAN standard, commonly referred to as WiMAX.
en.wikipedia.org /wiki/OFDM   (3568 words)

  
 OFDMA Resource Allocation   (Site not responding. Last check: 2007-09-08)
OFDMA, also referred to as Multiuser-OFDM, is being considered as a modulation and multiple access method for 4th generation wireless networks.
OFDMA is an extension of Orthogonal Frequency Division Multiplexing (OFDM), which is currently the modulation of choice for high speed data access systems such as IEEE 802.11a/g wireless LAN (WiFi) and IEEE 802.16a/d/e wireless broadband access systems (WiMAX).
OFDMA, on the other hand, allows multiple users to transmit simultaneously on the different subcarriers per OFDM symbol.
www.ece.utexas.edu /~iwong/OFDMAResAlloc.htm   (222 words)

  
 ISP Planet - Fixed Wireless - Technology - The Many Flavors of OFDMA
OFDMA technology, which splits a single channel into smaller channels has many uses, but no single standard protocol.
Start with a definition of Orthogonal Frequency Division Multiplexing (OFDM) from the ISP-Planet glossary: OFDM works by splitting the radio signal into multiple smaller sub-signals that are then transmitted simultaneously at different frequencies to the receiver.
With the advent of WiMAX, the terms OFDM and OFMDA, scalable OFDMA (sOFDMA), and Flarion's alternative version of OFDMA, Flash OFDM, have all become buzzwords—and subject to the standards process.
www.isp-planet.com /fixed_wireless/technology/2005/ofdma_flavors.html   (774 words)

  
 ISP Planet - Fixed Wireless - Technology - The Many Flavors of OFDMA - page two
A user close to the base station would normally be assigned a larger number of channels with a high modulation scheme such as 64 QAM (quadrature amplitude modulation) to deliver the most data throughput to that user.
The OFDMA 2048 FFT version was conceived as a fixed FFT and is supported in both 802.16-2004 and 802.16e.
The various flavors of OFDMA are about the demands of mobility and speed of handoffs, the size of the cell, spectrum range, channel sizes, and more.
www.isp-planet.com /fixed_wireless/technology/2005/ofdma_flavors_p2.html   (1075 words)

  
 Runcom to disclose the worlds first proven OFDMA® system at WCAI Convention
The OFDMA technology was recently recognized by leading standardization bodies as the recommended technology for Wireless Broadband Access.
Runcom will display at WCAI the first system in the world that implements the OFDMA technology that was recently approved by the Digital Video Broadcasting (DVB) Committee as an international standard and is the basic infrastructure for Wireless Interactive Television and is recommended for approval at the IEEE.802.16.a/b standardization bodies for Wireless Broadband Access Systems.
OFDMA technology enables simultaneous bi-directional flow of data for numerous subscribers at a high speed, according to their requirements.
www.runcom.com /news_full.asp?info_id=143   (411 words)

  
 Runcom Technologies Ltd. Explains the WiMAX OFDMA® standard — WIMAX
Now to your question, OFDMA® offers substantial advantages for fixed applications beyond mobility itself such as; bigger cells due to the processing gain, better multipath protection due to bigger FFT sizes especially in urban and Non Line of  Site (NLOS) environments, improved granularity for data and increased user capacity.
In addition, one of the biggest advantages of the OFDMA® solution is the subscriber and infrastructure equipment cost, that due to improved economies of scale, will be much lower.
Israel Koffman: Yes, we anticipate OFDMA® to be used in both 802.16e as well as in 802.16-2004 (Mobile and fixed applications).
www.wimax.com /commentary/spotlight/spotlight-runcomtech   (1716 words)

  
 All Hail OFDMA! | IT Business Edge
OFDMA, which is a radio frequency technique used to carry wireless signals, has been anointed as the next wave in transmission technology.
The main sign that OFDMA, which is said to be both faster and more robust than competitors, is the winner is that both 3G and WiMax vendors and operators say they will use it.
This, many people suggest, is a tacit acknowledgement that OFDMA is the (radio) wave of the future.
www.itbusinessedge.com /item/?ci=6464   (831 words)

  
 Deterministic multiuser carrier-frequency offset estimation for interleaved OFDMA uplink
In orthogonal frequency-division multiple access (OFDMA), closely spaced multiple subcarriers are assigned to different users for parallel signal transmission.
This paper exploits the inner structure of the signals for CFO estimation in the uplink of interleaved OFDMA systems.
A new uplink signal model is presented, and an estimation algorithm based on the signal structure is proposed for estimating the CFOs of all users using only one OFDMA block.
repositories.cdlib.org /postprints/641   (290 words)

  
 CommsDesign - Tap into the advantages of a scalable OFDMA engine for WiMAX
A scalable orthogonal frequency-division multiple access (OFDMA) engine for mobile worldwide interoperability for microwave access (WiMAX) can be used to accelerate the development of mobile broadband wireless networks based on the IEEE 802.16 standard.
Scalable OFDMA is a key technology behind mobile WiMAX and is widely regarded as an enabling technology for future broadband wireless protocols including the 3GPP and 3GPP2 long term evolution standards.
The Scalable OFDMA Reference design represents a module of the WiMAX Phyisical layer that is well defined by the specification and so this design may be used as a fl box in order to reduce development time.
www.commsdesign.com /story/showArticle.jhtml?articleID=193600473   (510 words)

  
 MIMO in ofdma in WiMax
12 Mar 2006 16:18 Re: MIMO in ofdma in WiMax
OFDMA is more sensitive to frequency offset and phase
OFDMA may be able to further improve its advantage
www.edaboard.com /ftopic147623.html   (520 words)

  
 Unstrung - WiMax/Broadband Wireless - All Hail OFDMA! - Wireless Networking News Analysis
OFDMA (orthogonal frequency division multiple access) is emerging as the clear choice for the next-generation radio interface in mobile wireless networks, said Mick Reeve, group technology officer at BT Group plc (NYSE: BT - message board; London: BTA), in his keynote at Light Reading’s Future of Telecom Europe event in London yesterday.
Reeve said that “almost everyone agrees” OFDMA will be the next major evolution in mobile wireless technology, but he noted there are unanswered questions about how, when, and by whom it will be implemented.
Interestingly, in its announcement of the acquisition, Qualcomm employed OFDMA terminology, even though Flarion had not previously used the term publicly.
www.unstrung.com /document.asp?doc_id=80357   (960 words)

  
 OFDM or OFDMA?
OFDMA is a multi-user OFDM that allows multiple access on the same channel (a channel being a group of evenly spaced subcarriers, as discussed above).
WiMAX uses OFDMA, extended OFDM, to accommodate many users in the same channel at the same time.
OFDMA distributes subcarriers among users so all users can transmit and receive at the same time within a single channel on what are called subchannels.
rfdesign.com /ar/ofdm-or-ofdma   (582 words)

  
 Patents Raise Price Of Qualcomm's Flarion Buy - Windows News by InformationWeek
"The rapid issuance of these patents is yet another indicator of Flarion's strength as an OFDMA innovator and further enhances Qualcomm's leadership position in the wireless industry," Qualcomm president Steven R. Altman said in a statement.
While cellular operators currently are building out their 3G cellular data networks, most industry observers expect the next generation of cellular data, often called 4G, to be based on OFDM or OFDMA technology.
Qualcomm said $185 million is payable in cash and that $75 million of that amount is not due to the former Flarion shareholders until July, 2007.
www.informationweek.com /windows/showArticle.jhtml?articleID=187200341   (353 words)

  
 Broadband Wireless Business Magazine
In OFDMA, the averaging is obtained by hopping a narrowband signal over a wider band.
Flarion has a world-class team and an expansive portfolio of OFDMA intellectual property, with 110 engineers and in excess of 100 issued and pending patents.
This sort of forward-looking development activity has always been our practice and is one of the factors that has enabled the Company to maintain its leadership position in the wireless space.
www.shorecliffcommunications.com /magazine/interview.asp?intv=520   (1163 words)

  
 [STDS-802-16] Uplink example for OFDMA   (Site not responding. Last check: 2007-09-08)
I just noticed that the uplink example for OFDMA (8.4.9.4.4) from Cor1/D5 is not included in 802.16e-2005.
Prev by Date: [STDS-802-16] OFDMA data mapping (Section 8.4.3.4 of Std 802.16e-2005.
Prev by thread: [STDS-802-16] OFDMA data mapping (Section 8.4.3.4 of Std 802.16e-2005.
www.wirelessman.org /arc/802-16list2/msg03218.html   (81 words)

  
 Untitled
Therefore, some new multiple access technology, such as orthogonal frequency division multiple access (OFDMA), has been proposed to replace CDMA as a prime air-link design for 4G wireless.
However, the OFDMA also suffers its own technical limitations, such as sensitivity to peak-to-average-power-ratio (PAPR), nonlinear channels and so forth, which will be the detrimental factors to its successful applications in 4G wireless.
The objective of this special issue is to accelerate technological evolution of air-link architecture for 4G wireless communications.
www.comsoc.org /pubs/pcm/cfpwireless06071.htm   (452 words)

  
 QUALCOMM Technology and Solutions - OFDM/OFDMA   (Site not responding. Last check: 2007-09-08)
OFDM and OFDMA wireless solutions will enable delivery of high-quality streaming video and audio programming.
OFDM technology is the underlying technology for QUALCOMM’s FLO (forward link only) air interface, the basis of the MediaFLO network the company is deploying in the U.S., and is used in combination with CDMA for CDMA2000 1xEV-DO Platinum Multicast.
“While CDMA remains the optimal technology to provide broadband, spectrally efficient, mobile wide area wireless networks for the foreseeable future, OFDMA's low complexity at wide signal bandwidths makes it a potential alternative where large blocks of spectrum can be dedicated.
www.qualcomm.com /technology/ofdma.html   (150 words)

  
 Qualcomm acquires OFDMA developer
Qualcomm Inc., one of the leading developers and innovators of CDMA, announced that it has completed the acquisition of Flarion Technologies, a developer of Orthogonal Frequency Division Multiplex Access (OFDMA) technology and the inventor of FLASH-OFDM technology for mobile broadband Internet protocol (IP) services.
As previously announced on Jan. 13, 2006, the Antitrust Division of the U.S. Department of Justice informed Qualcomm and Flarion that it had terminated its review of the transaction under the Hart-Scott-Rodino Act.
Qualcomm expects the acquisition to contribute approximately 2 cents dilution to pro forma earnings per share and an additional 1 cent dilution to total Qualcomm earnings per share in its fiscal year ending September 2006.
www.eetasia.com /ART_8800404881_590626_166f5f45.HTM   (350 words)

  
 Scalable OFDMA Physical Layer in IEEE 802.16 WirelessMAN   (Site not responding. Last check: 2007-09-08)
The concept of scalability was introduced to the IEEE 802.16 WirelessMAN Orthogonal Frequency Division Multiplexing Access (OFDMA) mode by the 802.16 Task Group e (TGe).
The architecture is based on a scalable subchannelization structure with variable Fast Fourier Transform (FFT) sizes according to the channel bandwidth.
The purpose of this paper is to provide a brief tutorial on the IEEE 802.16 WirelessMAN OFDMA with an emphasis on scalable OFDMA.
www.xlnt.com /technology/itj/2004/volume08issue03/art03_scalableofdma/p01_abstract.htm   (232 words)

  
 The Many Flavors of OFDMA
For a variety of reasons, it appears most likely that the first product profile chosen by the Forum may be a sOFDMA one, though that is not certain as of press time for this article.
There are three types of OFDMA subcarriers: Data subcarriers for data transmission, Pilot subcarriers for various estimation and synchronization purposes, and Null subcarriers for no transmission at all, used for guard bands and DC carriers.
(Intel Technology Journal) The concept of scalability was introduced to the IEEE 802.16 WirelessMAN Orthogonal Frequency Division Multiplexing Access (OFDMA) mode by the 802.16 Task Group e (TGe).
www.webopedia.com /DidYouKnow/Computer_Science/2005/OFDMA.asp   (1743 words)

  
 Shopping Cart Website Sell Online Internet
and OFMDA, scalable OFDMA (sOFDMA), and Flarion's alternative version of OFDMA, Flash OFDM, have all become buzzwords.and subject to the standards process.
There is a third flavor of OFDMA competitive to
wireless forces the designers of OFDMA to make choices, and those choices have tradeoffs.
www.rdspc.com /knowledge/facts/ofdma.asp   (1083 words)

  
 Charles River Ventures - News & Events - Portfolio News
Flarion, with a world-class team and an expansive portfolio of OFDMA intellectual property, has worked closely with several operators worldwide in developing and demonstrating OFDMA technology and products.
Completion of the acquisition, which is subject to regulatory approval and other customary closing conditions, is expected later this year.
Upon the closing of the transaction, of the $600 million, QUALCOMM estimates that it will issue stock with a value of approximately $267 million, assume existing Flarion options and warrants with a fair value of approximately $128 million, and pay approximately $205 million in cash, net of Flarion's projected cash balance.
www.crv.com /NewsEvents/News/newsAug112005.html   (776 words)

  
 Amazon.com: OFDMA   (Site not responding. Last check: 2007-09-08)
OFDMA for Broadband Wireless Access (Artech House Mobile Communications) by Slawomir Pietrzyk (Hardcover - April 30, 2006)
Resource allocation in OFDMA based broadband wireless access systems: (Dissertation) by Dorathy E. Dasary (Aug 1, 2006)
Space-time block-coded OFDMA with linear precoding for multirate...
www.amazon.com /s?ie=UTF8&keywords=OFDMA&tag=acronymfinder-20&index=blended&link_code=qs&page=1   (759 words)

  
 QUALCOMM Press Center - QUALCOMM Completes Acquisition of Flarion Technologies
As previously announced, on Jan. 13, 2006 the Antitrust Division of the United States Department of Justice informed QUALCOMM and Flarion that it had terminated its review of the transaction under the Hart-Scott-Rodino Act (see QUALCOMM announcement, Jan. 16, 2006).
QUALCOMM expects the acquisition to contribute approximately $0.02 dilution to pro forma earnings per share - primarily R&D expense - and an additional $0.01 dilution to total QUALCOMM earnings per share - primarily stock option expense and a one-time in-process R&D charge - in its fiscal year ending September 2006.
Flarion has a world-class team and an expansive portfolio of OFDMA intellectual property.
www.qualcomm.com /press/releases/2006/060119_completes_acquisition_flarion.html   (406 words)

  
 Hui Liu - UWEE Faculty
Guoqing Li and Hui Liu, "On the optimality of OFDMA networks," IEEE Communications Letters, to appear.
Guoqing Li and Hui liu, "On the Optimality of Downlink OFDMA MIMO Systems," accepted, the 62nd IEEE Vehicular Technology Conference, Dallas, TX, USA, September 25-28, 2005.
Manyuan Shen, Guoqing Li, and Hui Liu, "Design tradeoffs in OFDMA traffic channels," International Conference on Acosutics, Speech, and Signal Processing, Montreal, Canada, May 17-21, 2004.
www.ee.washington.edu /people/faculty/liuh   (915 words)

  
 Wavesat and SK Telecom Sign Agreement to Develop WIBRO OFDMA Solutions   (Site not responding. Last check: 2007-09-08)
As part of this multi-million dollar agreement, Wavesat will work closely with SK Telecom (SKT) to develop WiBro/OFDMA SOC, system tools and a development kit based on the WiBro 802.16e S-OFDMA profile.
The new UMobile(TM) (Ultra-Mobile) family of OFDMA WIMAX product portfolio from Wavesat will allow WiMax Wireless system providers (OEMs/ODMs) worldwide to quickly develop and deploy full mobility WiMAX and WiBro solutions.
We decided to work with Wavesat to develop our WiBro/OFDMA technology because of their unique understanding and successful track record in OFDM technologies and WiMAX solutions as well as their leading involvement with the WiMAX Forum and IEEE Standards Body," said Dr. JooSik Lee, Vice President of SK Telecom.
www.telstreet.com /forum/m-718/tm.html   (454 words)

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