Ofdm, orthogonal frequency division multiplex is the basic format used and this is modified to provide the multiple access scheme. Implementation of ofdma and multiple antenna techniques. Orthogonal frequency division multiple access ofdma is the property of its rightful owner. References to qualcomm may mean qualcomm incorporated, or subsidiaries or business units within the qualcomm corporate structure, as applicable. Ofdma physical layer basics mobile wimax physical layer as. Introduction in order to transition from todays 3rd generation 3g communications systems to meet the needs of 4th. Hence, lte uses single carrier fdma scfdma with cyclic prefix on the uplink which reduces papr as there is only a single carrier as opposed to n carriers.
Both ofdm and ofdma are used in many modern wireless systems including acmimo radio, 802. Scfdma is examined in this paper as a promising alternative to ofdma. Ofdma physical layer basics mobile wimax physical layer. Hafez and others published resource allocation in ofdma femtocell based lte and 5g networks with qos guarantees find, read and cite all the research you need on. Orthogonal frequency division multiplexing access ofdma and single carrier frequency division multiple access scfdma are currently used for. Multiple access is achieved in ofdma by assigning subsets of subcarriers to individual users. The long term evolution lte takes the orthogonal frequency division multiple access ofdma as the multiple access technique for downlink to transmit data from base station to the mobile users mus because of its ability to improve the spectrum efficiency, it has flexible user resource allocation, it can overcome the problems of inter symbol interchange isi and inter carrier. The long term evolution lte takes the orthogonal frequency division multiple access ofdma as the multiple access technique for downlink to transmit data from base station to the mobile users. Long term evolution is a new advancement in the era of cellular technology emerged in recent decade that can accommodate the features of quite efficient radio access with high peak data rates as well as high capacity for voice links. Although ofdm is capable of delivering the target peak data rates, its high papr raises questions as to its suitability in the uplink. Ofdm support multiple users multiple access via tdma basis only, while ofdma support either on tdma or fdma basis or both at the same time. Fundamentals of lte download ebook pdf, epub, tuebl, mobi.
The normal cyclic prefix is intended to be sufficient for the majority of scenarios, while the extended cyclic prefix is intended for scenarios with particularly high delay spread. Implementation of ofdma and multiple antenna techniques in. The detailed specification of lte is given in table 1. It starts with an indepth explanation of the background and standardization process before moving on to examine the system architecture evolution sae.
Click download or read online button to get lte the umts long term evolution book now. Introduction to ofdm university of california, berkeley. Orthogonal frequencydivision multiple access wikipedia. Mobile wimax ofdma physical layer consists of scrambler,convolution coding,interleaving, repetition. Ofdma, orthogonal frequency division multiple access in the downlink and scfdma, single channel orthogonal frequency division multiple access in the uplink. Sep 08, 2016 ofdm ofdma in 4g lte part 1 how can we stream a full hd movies seamlessly. Whats the difference between ofdma and mumimo in 11ax. Difference between ofdm and ofdma compare the difference. Jul 31, 2014 pointtomultipoint fixed and mobile systems use ofdma and most emerging systems are using ofdma such as mobile wimax and lte. Uplink downlink user 1 user 2 user 3 scfdma ofdma figure 1. Ofdm ofdma in 4g lte part 1 how can we stream a full hd movies seamlessly. Orthogonal frequency division multiple access ofdma lte. Here we are giving you lte seminar and ppt with pdf. Orthogonal frequency division multiple access ofdma basestations allow multiple users to transmit simultaneously on different subcarriers during the same symbol period.
Ofdma incorporates elements of time division multiple access tdma so. The tabular comparison between ofdm and ofdma are also outlined. Click download or read online button to get fundamentals of lte book now. Ofdm enhancements using multiantenna mimo and multiuser ofdma are then described.
The first part of the course focuses on the principles of orthogonal frequency division multiplexing ofdm, which forms the basis of 4g5gwifi systems. This allows simultaneous lowdatarate transmission from several users. From the editors of the highly successful wcdma for umts, this new book gives a complete and uptodate overview of long term evolution lte in a systematic and clear manner. Performance analysis of scfdma and ofdma in lte frame. It presents in a unique way the principles, basics and advanced elements of wireless ofdma technology, and also provides a future centric perspective of practical aspects of wireless communications. Find a library or download libby an app by overdrive. If so, share your ppt presentation slides online with. Ofdma orthogonal frequency division multiple access one of the key elements of lte is the use of ofdm orthogonal frequency division multiplex as the signal bearer, as well as ofdms associated access schemes, ofdma orthogonal frequency division multiple access and scfdma single carrier frequency division multiple access. Ofdm forms the basic signal format used within 4g lte. Ofdm with a cyclic prefix cp in the downlink, and on single carrier.
In ofdmtdma, timeslots are attributed to each users and the whole ofdm symbol is dedicated to one user. Fundamentals of communications access technologies. Orthogonal frequencydivision multiple access ofdma is a multiuser version of the popular orthogonal frequencydivision multiplexing ofdm digital modulation scheme. This article provides a comprehensive overview of the implementation of orthogonal frequency division multiple access along with multiple antenna schemes in the two dominant 4g standards, wimax and.
Ofdm is the modulation of choice for the lte downlink, the key advantages being the low complexity of the receiver, high spectral efficiency and avoidance of inter. Ofdma as 3gpp longterm evolution uplink friday december 4, 2009 ee359 project nima soltani 1. Ppt orthogonal frequency division multiple access ofdma. Ofdma can also be used as an uplink access scheme, where specific subchannels are assigned to specific ues via mac messages sent on dls. All you need to do is just click on the download link and get it. Dec 17, 2015 fundamentals of communications access technologies. This paper provides the introduction of lte and the key components of its physical layer. In lte, the ofdma is used as downlink and scfdma as uplink modulation schemes. Lte an optimized ofdma solution for wider bandwidth spectrum. An overview of lte and wifi is provided next, together with a comparative assessment of the. Download product flyer is to download pdf in new tab. Its design incorporates many of the key innovations of digital communication, such as mimo multiple input multiple output and ofdma orthogonal frequency division multiple access, that mandate new skills to plan, build, and deploy an lte network. Pdf performance analysis of scfdma and ofdma in lte frame. This page covers ofdma basics, ofdma frame structure, ofdma symbol structure and ofdma physical layer as per ieee 802.
Durations for the normal and extended cyclic prefix are. Robust again narrowband interference ldisadvantages. In addition to its benefits, key ofdm metrics are discussed. This multiplexing digital modulation scheme introduces newfound permeability into highly dense wifi traffic scenarios. Apr 07, 2017 one of the key features driving this connectivity improvement is orthogonal frequencydivision multiple access ofdma. In fundamentals of lte, four leading experts from academia and industry explain the technical. Ofdma is used for downlink direction, for uplink direction scfdma is used in lte. In this tutorial article, we discuss the reasons for the popularity of ofdma and outline some of the important concepts which are used in ofdma as applied to bcw systems. Lte specifies both normal and extended cyclic prefix lengths. Scfdma was chosen since it combines the low papr techniques of singlecarrier transmission systems, such as gsm and cdma, with the multipath resistance and flexible frequency allocation of. Pdf performance analysis of ofdma in lte researchgate. Figure 2 illustrates the concepts of ofdma and scfdma.
Lte has since adopted ofdma technology as the converged global 4g standard. Long term evolution lte is consents pliable spectrum distribution which renders enriched wireless data services to users at lower latency and multimegabit throughput. This page compares scfdma vs ofdma and mentions difference between scfdma and ofdma modulation techniques. Ofdma is also used by lte networks as the means of multiuser transmission. Orthogonal frequency division multiple access ofdma is the multiuser variant of the ofdm. Ofdma principles in lte, there are several ways to transmit over the frequency band and to share the resource between several devices. For practicality, scofdma is implemented in lte using a discrete fourier transform spread ofdm transmission. For every advantage engineered, there is always a price. Let us understand comparison between them with example of qpsk data symbols which need to be transmitted as shown in the figure1. Joint subcarrier and power allocation in ofdma is a complex problem 1. If you liked it then please share it or if you want to ask anything then please hit comment button. Individual copies of the present document can be downloaded from. In case of dispute, the reference shall be the printing on etsi printers of the pdf version kept on a.
The physics of broadband wireless forces the designers of ofdma to make choices, and those choices have tradeoffs. Qualcomm products referenced on this page are products of qualcomm technologies, inc. Lte for umts ofdma and scfdma based radio access lte for umts ofdma and scfdma based radio access pdf, epub ebook d0wnl0ad from the editors of the highly successful wcdma for umts, this new book gives a complete and uptodate overview of long term evolution lte in a systematic and clear manner. Pdf resource allocation in ofdma femtocell based lte and. Lte for umtsofdma and scfdma based radio access overdrive. Frequency division multiple access ofdma in downlink dl and single carrier frequency division multiple access scfdma for uplink ul, as shown in figure 3. Subcarriers are orthogonal to each other in the system. Using a large number of parallel narrowband subcarriers instead of a single wideband carrier to transport information ladvantages. Ofdma that gives fair allocation of capacity to multiple users with different channel. Ofdma channel access method code division multiple access. At first, it may appear as though ofdma offers no added.
Access scfdma for downlink and uplink transmission where ofdma has been acquired in lte for. Aug 22, 2014 lte for umts ofdma and scfdma based radio access lte for umts ofdma and scfdma based radio access pdf, epub ebook d0wnl0ad from the editors of the highly successful wcdma for umts, this new book gives a complete and uptodate overview of long term evolution lte in a systematic and clear manner. These descriptions are simplified version of the detailed descriptions provided by 3gpp. Jun, 2015 uplink downlink user 1 user 2 user 3 scfdma ofdma figure 1. Ofdma is used for achieving high spectral efficiency in communication system.
One feature ofdma seems much more significant than the others. Pdf long term evolution lte is consents pliable spectrum distribution which renders. To overcome the effect of multi path fading problem available in umts, lte uses orthogonal frequency division multiplexing ofdm for the downlink that is, from the base station to the terminal to transmit the data over many narrow band careers of 180 khz each instead of spreading one signal over the complete 5mhz career bandwidth ie. This chapter presents an overview of the theoretical background of ofdm together with its parameterization for lte. Lte basics part i ofdma and lte frame structures youtube. This page on the ofdm vs ofdma describes difference between ofdm and ofdma modulation schemes. Materials that are as of a specific date, including but not limited to press releases, presentations, blog posts and webcasts, may have been superseded by subsequent events or disclosures. Ofdm with a cyclic prefix cp in the downlink, and on singlecarrier. Please visit our website in order to download the latest version. In ofdm systems, only a single user can transmit on all of the subcarriers at any given time. Jul 05, 2016 ofdma can be used as a dl access scheme, with the mac layer assigning subchannels to the dl data destined to the various ues. This article describes ofdma basics, ofdma frame structure, ofdma symbol, ofdma physical layer as per ieee 802.
Orthogonal frequency division multiple access ofdma. Lte lte advanced for mobile broadband pdf, epub, docx and torrent then this site is not for you. Ofdma allows multiple users to transmit simultaneously on different subcarriers per ofdm symbol. Pdf on the ofdma fdd mode in 3glte rainer schoenen. This video explains the lte technology basics, ofdma and lte frame structures and types. One of the key requirements of next generation networks ngns is the support of higher data rates. Performance analysis of ofdma in lte ieee conference. This site is like a library, use search box in the widget to get ebook that you want. Jul 27, 20 this video explains the lte technology basics, ofdma and lte frame structures and types. Lte the umts long term evolution download ebook pdf, epub. In ofdma, both time and frequency are distributed among users. Pdf the lte employs ofdma for downlink data transmission because orthogonal frequency division multiple. Ofdma tdd frame in mobile wimax consists of pusc, fusc and amc zones in the downlink and puscamc zones in the uplink.
Study of multiple access schemes in 3gpp lte ofdma vs. Here we give a comparison of the advantages and disadvantages of ofdma ofdm and cdma is often necessary to choose the correct system. Orthogonal frequency division multiple access an overview. Download pdf data sheet for lte physical layer design. Multipleaccess ofdma, using the same numerologies as lte in terms of subcarrier. Lte, orthogonal frequency division multiplexing ofdm and peak to average power ratio papr. It also explains ofdma tdd frame which consists of pusc, fusc and amc zones in the downlink and puscamc zones in the uplink. Lte uses orthogonal frequency division multiple access ofdma and single carrier frequency division multiple access scfdma for downlink and uplink transmission where ofdma has been acquired in lte for downlink transmission. Fundamentals of lte ebook by arunabha ghosh rakuten kobo. 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. For practicality, sc ofdma is implemented in lte using a discrete fourier transform spread ofdm transmission. Lte for umts ofdma and sc fdma based radio access april 2009.