Ofdm enhancements using multiantenna mimo and multiuser ofdma are then described. Orthogonal frequency division multiple access ofdma basestations allow multiple users to transmit simultaneously on different subcarriers during the same symbol period. Performance analysis of ofdma in lte ieee conference. This paper provides the introduction of lte and the key components of its physical layer. It also explains ofdma tdd frame which consists of pusc, fusc and amc zones in the downlink and puscamc zones in the uplink. This page on the ofdm vs ofdma describes difference between ofdm and ofdma modulation schemes. Scfdma is examined in this paper as a promising alternative to ofdma. In lte, the ofdma is used as downlink and scfdma as uplink modulation schemes. One of the key requirements of next generation networks ngns is the support of higher data rates. Study of multiple access schemes in 3gpp lte ofdma vs. An overview of lte and wifi is provided next, together with a comparative assessment of the. Orthogonal frequency division multiplexing access ofdma and single carrier frequency division multiple access scfdma are currently used for. Click download or read online button to get fundamentals of lte book now. Orthogonal frequencydivision multiple access ofdma is a multiuser version of the popular orthogonal frequencydivision multiplexing ofdm digital modulation scheme.
Whats the difference between ofdma and mumimo in 11ax. For practicality, scofdma is implemented in lte using a discrete fourier transform spread ofdm transmission. Frequency division multiple access ofdma in downlink dl and single carrier frequency division multiple access scfdma for uplink ul, as shown in figure 3. Orthogonal frequency division multiple access an overview. Ofdm ofdma and 4g 5g systems uc san diego extension. Ofdm with a cyclic prefix cp in the downlink, and on single carrier. Ppt orthogonal frequency division multiple access ofdma.
Mobile wimax ofdma physical layer consists of scrambler,convolution coding,interleaving, repetition. Ofdma is also used by lte networks as the means of multiuser transmission. Lte, orthogonal frequency division multiplexing ofdm and peak to average power ratio papr. Lte basics part i ofdma and lte frame structures youtube. Dec 17, 2015 fundamentals of communications access technologies. Lte the umts long term evolution download ebook pdf, epub. Implementation of ofdma and multiple antenna techniques. Qualcomm products referenced on this page are products of qualcomm technologies, inc. Although ofdm is capable of delivering the target peak data rates, its high papr raises questions as to its suitability in the uplink.
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. Orthogonal frequency division multiple access ofdma lte. This article describes ofdma basics, ofdma frame structure, ofdma symbol, ofdma physical layer as per ieee 802. If so, share your ppt presentation slides online with. This chapter presents an overview of the theoretical background of ofdm together with its parameterization for lte. 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. Here we are giving you lte seminar and ppt with pdf.
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. Ofdma is used for downlink direction, for uplink direction scfdma is used in lte. Ofdma principles in lte, there are several ways to transmit over the frequency band and to share the resource between several devices. Performance analysis of scfdma and ofdma in lte frame. Orthogonal frequency division multiple access ofdma. Joint subcarrier and power allocation in ofdma is a complex problem 1. 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. Difference between ofdm and ofdma compare the difference. 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. This video explains the lte technology basics, ofdma and lte frame structures and types.
References to qualcomm may mean qualcomm incorporated, or subsidiaries or business units within the qualcomm corporate structure, as applicable. Fundamentals of lte download ebook pdf, epub, tuebl, mobi. In fundamentals of lte, four leading experts from academia and industry explain the technical. For every advantage engineered, there is always a price.
Lte for umtsofdma and scfdma based radio access overdrive. Ofdma allows multiple users to transmit simultaneously on different subcarriers per ofdm symbol. Uplink downlink user 1 user 2 user 3 scfdma ofdma figure 1. Ofdma is used for achieving high spectral efficiency in communication system.
Lte for umts ofdma and sc fdma based radio access april 2009. Ofdma can also be used as an uplink access scheme, where specific subchannels are assigned to specific ues via mac messages sent on dls. For practicality, sc ofdma is implemented in lte using a discrete fourier transform spread ofdm transmission. 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. Sep 08, 2016 ofdm ofdma in 4g lte part 1 how can we stream a full hd movies seamlessly. Pdf on the ofdma fdd mode in 3glte rainer schoenen. Durations for the normal and extended cyclic prefix are. Robust again narrowband interference ldisadvantages. 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. Jun, 2015 uplink downlink user 1 user 2 user 3 scfdma ofdma figure 1. Lte lte advanced for mobile broadband pdf, epub, docx and torrent then this site is not for you. Ofdm ofdma in 4g lte part 1 how can we stream a full hd movies seamlessly. Orthogonal frequency division multiple access ofdma is the property of its rightful owner. The first part of the course focuses on the principles of orthogonal frequency division multiplexing ofdm, which forms the basis of 4g5gwifi systems.
Orthogonal frequency division multiple access ofdma is the multiuser variant of the ofdm. 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. Find a library or download libby an app by overdrive. 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. This page covers ofdma basics, ofdma frame structure, ofdma symbol structure and ofdma physical layer as per ieee 802. In ofdm systems, only a single user can transmit on all of the subcarriers at any given time. Orthogonal frequencydivision multiple access wikipedia. Pdf performance analysis of ofdma in lte researchgate. Here we give a comparison of the advantages and disadvantages of ofdma ofdm and cdma is often necessary to choose the correct system.
Apr 07, 2017 one of the key features driving this connectivity improvement is orthogonal frequencydivision multiple access ofdma. Introduction to ofdm lbasic idea using a large number of parallel narrowband subcarriers instead of a single wideband carrier to transport information ladvantages very easy and efficient in dealing with multipath robust again narrowband interference ldisadvantages sensitive to frequency offset and phase noise. Individual copies of the present document can be downloaded from. 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. Multiple access is achieved in ofdma by assigning subsets of subcarriers to individual users. In ofdma, both time and frequency are distributed among users. In ofdmtdma, timeslots are attributed to each users and the whole ofdm symbol is dedicated to one user. Ofdma as 3gpp longterm evolution uplink friday december 4, 2009 ee359 project nima soltani 1. Ofdma channel access method code division multiple access. 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. Jul 27, 20 this video explains the lte technology basics, ofdma and lte frame structures and types. Implementation of ofdma and multiple antenna techniques in. 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.
These descriptions are simplified version of the detailed descriptions provided by 3gpp. It starts with an indepth explanation of the background and standardization process before moving on to examine the system architecture evolution sae. Figure 2 illustrates the concepts of ofdma and scfdma. At first, it may appear as though ofdma offers no added. Subcarriers are orthogonal to each other in the system. Let us understand comparison between them with example of qpsk data symbols which need to be transmitted as shown in the figure1. The detailed specification of lte is given in table 1. Fundamentals of communications access technologies. Multipleaccess ofdma, using the same numerologies as lte in terms of subcarrier. Ofdm with a cyclic prefix cp in the downlink, and on singlecarrier. 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.
In case of dispute, the reference shall be the printing on etsi printers of the pdf version kept on a. 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. Introduction in order to transition from todays 3rd generation 3g communications systems to meet the needs of 4th. If you liked it then please share it or if you want to ask anything then please hit comment button. This site is like a library, use search box in the widget to get ebook that you want.
One feature ofdma seems much more significant than the others. 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. Download pdf data sheet for lte physical layer design. All you need to do is just click on the download link and get it. 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. Jul 31, 2014 pointtomultipoint fixed and mobile systems use ofdma and most emerging systems are using ofdma such as mobile wimax and lte. Both ofdm and ofdma are used in many modern wireless systems including acmimo radio, 802. 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.
This allows simultaneous lowdatarate transmission from several users. Long term evolution lte is consents pliable spectrum distribution which renders enriched wireless data services to users at lower latency and multimegabit throughput. Pdf resource allocation in ofdma femtocell based lte and. Download product flyer is to download pdf in new tab. This multiplexing digital modulation scheme introduces newfound permeability into highly dense wifi traffic scenarios. Lte an optimized ofdma solution for wider bandwidth spectrum. Ofdm, orthogonal frequency division multiplex is the basic format used and this is modified to provide the multiple access scheme. Introduction to ofdm university of california, berkeley. Ofdm forms the basic signal format used within 4g lte. Pdf long term evolution lte is consents pliable spectrum distribution which renders. Lte specifies both normal and extended cyclic prefix lengths. Click download or read online button to get lte the umts long term evolution book now. 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.
The tabular comparison between ofdm and ofdma are also outlined. 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. Using a large number of parallel narrowband subcarriers instead of a single wideband carrier to transport information ladvantages. Pdf performance analysis of scfdma and ofdma in lte frame.
Access scfdma for downlink and uplink transmission where ofdma has been acquired in lte for. Ofdma, orthogonal frequency division multiple access in the downlink and scfdma, single channel orthogonal frequency division multiple access in the uplink. Ofdma that gives fair allocation of capacity to multiple users with different channel. In addition to its benefits, key ofdm metrics are discussed. 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. Please visit our website in order to download the latest version.
Lte has since adopted ofdma technology as the converged global 4g standard. This page compares scfdma vs ofdma and mentions difference between scfdma and ofdma modulation techniques. Ofdma tdd frame in mobile wimax consists of pusc, fusc and amc zones in the downlink and puscamc zones in the uplink. 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. 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.