Pdf comparison of ofdma and gfdma for nextgeneration pons. Tutorial 22 orthogonal frequency division multiplex. The main difference between an ofdm and an ofdma orthogonal frequency division multiple access system if the fact that in the ofdm the user are allocated on the time domain only while using an ofdma system the user would be allocated by both time and frequency. Ofdm transmitter modules as per wlan11a standard, read more. Wireless tutorial wifi, 4g, 3g, white spaces and beyond. Orthogonal frequency division multiple access ofdma. Orthogonal frequency division multiple access ofdma basestations allow multiple users to transmit simultaneously on different subcarriers during the same symbol period. In this paper spatial multiplexingmimo communication schemes with ofdm modulation are considered with a focus on 4x4 systems. Was signal quality impacted buy the event that caused the recording to be triggered.
If we have multiple sources of internet data that must be delivered by one device in the case of docsis the cable modem termination system or cmts to multiple receivers cable modems cm in a physically connected node, the data needs to multiplexed, either in time or over the modulated. Using a large number of parallel narrowband subcarriers instead of a single wideband carrier to transport information ladvantages. While ofdm is used in many broadband technologies such as wimax16d16e, wlan11a11n11ac. One feature ofdma seems much more significant than the others. Ofdma as 3gpp longterm evolution uplink friday december 4, 2009 ee359 project nima soltani 1.
For fdd, 10 subframes are available for downlink transmission and 10 subframes. Ofdma and mimo notes 1 ee442 spring semester lecture 14 orthogonal frequency division multiplexing ofdm is a digital multicarrier modulation technique extending the concept of single subcarrier modulation by using multiple subcarriers over the channel. Comparison of ofdma and gfdma for nextgeneration pons. In this contex different channelaware scheduling algorithms have been proposed due to the resource allocation differences between the two schemes. Separate turbo code and single turbo code adaptive ofdm transmissions, lei ye and alister burr.
Difference between ofdm and ofdma compare the difference. Ofdm symbol windowing allows other ofdm symbols transmission 0 0. Robust again narrowband interference ldisadvantages. This article is an editorial note submitted to ccr.
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. Artificial intelligenceaided receiver for a cpfree ofdm system. Multiple access is achieved in ofdma by assigning subsets of subcarriers to individual users. Orthogonal frequency division multiplex ofdm, dmt download. Subcarriers in ofdm it is easy to see that these subcarriers are orthogonal, i.
It can be straightforwardly extended to a multiaccess scheme called ofdma, where each user is assigned a different set of subcarriers. As mentioned dft before ifft of ofdma and idft after dft of ofdma system make it scfdma. Ofdm works by splitting the radio signal into multiple smaller subsignals that are then transmitted simultaneously at different frequencies to the receiver. Determine if the transient spectral behavior caused bit errors determine root cause. Oct 27, 2014 multiplexing has nothing to do with modulation. This page provide comparison between ofdm vs cdma and mentions difference between ofdm and cdma technologies. With a single image, the user can perform segmentation, attributes extraction, normalization and classification.
An overview of ofdm variants and their applications. The author takes full responsibility for this articles technical content. Ofdm is a scheme that offers good resistance to multipath and is now widely recognized as the method of choice for mitigating multipath for broadband wireless. Singlecarrier fdma scfdma is a frequencydivision multiple access scheme. The cp in ofdm consumes additional resource and reduces spectrum and energy efficiency. Figure mentions modules unique to the scfdma and in common with ofdma system. Here we give a comparison of the advantages and disadvantages of ofdma ofdm and cdma is often necessary to choose the correct system.
However, both are based on the same concept of bundling evenly spaced multiple subcarriers with special characteristics into one. The same questions arose later in wireless communications, and ofdm transmission with. Orthogonal frequency division multiplexing ofdm is a multicarrier transmission technique that has. In telecommunications, orthogonal frequencydivision multiplexing ofdm is a type of digital transmission and a. High symbol and data integrity by transmitting at a relatively slow symbol rate to mitigate multipath effects and reduce the impact of impulsive noise, and by spreading data streams over multiple subcarriers with symbol. Jun 19, 2017 ofdm ofdma part 1 fundamentals of 4g lte. Orthogonal frequency distribution and multiple access, one of the major technology used in wireless data communications for bulk data transfer. The scalable or sofdma versions encompass the 128 fft, 512 fft, and 1024 fft as promoted by intel and others.
Obo runs in parallel of edca backoffs, and manages the medium access onto ul ofdma. Jul 31, 2014 ofdm vs ofdma ofdm orthogonal frequency division multiplexing and ofdma orthogonal frequency division multiple access are both wideband digital communication technologies with a slight difference between them. May 01, 2012 for the love of physics walter lewin may 16, 2011 duration. Random access procedure with trigger frames using ofdma. Llttee ooffddmm tteecchhnnoollooggyy 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. Comparison of the tse with respect to the cell radius. Orthogonal frequencydivision multiple access ofdma is a multiuser version of the popular orthogonal frequencydivision multiplexing ofdm digital modulation scheme.
Calculate and analyze ber results for the entire gapfree recorded frames in order to answer the question. System free of channel problems inherent in changing mobile communication systems. View pdf ofdma architectures, protocols, and applications. Tutorial 22 orthogonal frequency division multiplex ofdm, dmt posted on december 17, 2012 by charan l. It starts with an indepth explanation of the background and standardization process before moving on to examine the system architecture evolution sae. Nitin chore abstract orthogonal frequency division multiplexing ofdm is a modulation technique which is now used in most new and. Ofdm ofdm stands for orthogonal frequency division multiplexing.
This page on the ofdm vs ofdma describes difference between ofdm and ofdma modulation schemes. The only difference is the presence of the dft in scfdma. Basic lte architecture video eutran, enodeb, epc, sgw, pgw, mme, hss, pdn by telcoma global duration. On the receiving side of the ofdma system we should expect an fft operation that will them convert the symbol to the frequency domain again. Ofdm variation with cell radius 50 100 150 200 0 50 100 150 200 250 cell radius tse cpofdm zpofdm cdmalmmse cdmarake figure. Scfdma is widely used in lte subscriber terminals in the transmit path and its variant ofdma is used in the enodeb downlinkor receive path of lte subscribers. One company in the forefront of this type of ofdma technology is runcom.
Cdma, ofdmofdma, and other cyclic prefix cpbased air interfaces. In ofdm systems, only a single user can transmit on all of the subcarriers at any given time. What is ofdm orthogonal frequency division multiplexing. Cdma, ofdm ofdma, and other cyclic prefix cpbased air interfaces. In order to support multiple users time andor frequency division access techniques are used in ofdm. Figure2 depicts the block diagram of scfdma and ofdma system. Such a lowcost multiple air interface module can be implemented in a single terminal to enable global connectivity and interoperability. Scfdma vs ofdma, difference between scfdma and ofdma read more. The major setback to this static multiple access scheme is the fact that the different users see the. Refer ofdm vs ofdma and scfdma vs ofdma for more information on ofdma technique. The technologies such as mobile wimax, lte, lteadvanced and 5g uses ofdma technique for resource sharing. The main difference between an ofdm and an ofdma orthogonal frequency division multiple access system if the fact that in the ofdm the user are allocated on the time domain only while using an ofdma.
Ofdm reduces the amount of crosstalk in signal transmissions. The orthogonal frequency division multiple access ofdma scheme has been selected as a potential candidate for many emerging broadband wireless access standards. For the love of physics walter lewin may 16, 2011 duration. Multiuser multipleinput, multipleoutput mumimo and orthogonal frequency division multiple access ofdma are two of the most. Noma vs ofdma difference between noma and ofdma 5g. Ofdm versus ofdma in ofdm systems, only a single user can transmit on all of the subcarriers at any given time. Both cdma and ofdma are promising technologies for 3. Like other multiple access schemes tdma, fdma, cdma, ofdma, it deals with the assignment of multiple users to a shared communication resource. Geodma is a plugin for terraview software, used for geographical data mining. Introduction system model metric numerical results conclusion 2. Apr 25, 2011 orthogonal frequency distribution and multiple access, one of the major technology used in wireless data communications for bulk data transfer. Secure collisionfree frequency hopping for ofdma based.
The orthogonal frequency division multiple access ofdma based systems are being adopted for use in different flavors of bcw systems 1. Ofdm signal generation and decoding using 64qam as the modulation technique. Orthogonal frequencydivision multiple access wikipedia. In order to achieve the 3gpp lte and 3gpp ltea requirements, the design of detectors architecture with high. Ofdma architectures, protocols, and applications downloads. Orthogonal frequencydivision multiplexing wikipedia. 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. The ofdma 2048 fft version was conceived as a fixed fft and is supported in both 802.
Ofdma outperforms scfdma also for a high number of frequency multiplexed users, due to its more flexible resource allocation. This allows simultaneous lowdatarate transmission from several users. A counter maintained by the sta that determines the random access ru the sta utilizes. The tabular comparison between ofdm and ofdma are also outlined. Another way to see this intuitively is to use the analogy of making a shipment via a truck. An overview of ofdm variants and their applications nilesh chide, shreyas deshmukh, prof. This is useful for lte since it makes possible to exploit frequency dependence. This type of ofdm is particularly useful for wimax and other wireless and multimedia standards. Introduction in order to transition from todays 3rd generation 3g communications systems to meet the needs of 4th.
The detailed specification of lte is given in table 1. If we have multiple sources of internet data that must be delivered by one device in the case of docsis the cable modem termination system or cmts to multiple receivers cable modems cm in a physically connected node, the data needs to multiplexed, either in time or over the modulated subcarriers or in time, subcarrier blocks. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Rather than transmit a highrate stream of data with a single carrier, ofdm. Name company address phone email eli sofer runcom 2 hachoma st.
Orthogonal frequency division multiplexing for wireless channels leonard j. Both ofdm and cdma are wideband wireless digital communication systems widely used for fixed as well as mobile applications. This acronym designates protocols for allowing multiple users to the same radio channel. Figure 1 shows the generic frame structure that can be used in either fdd or tdd mode. For this reason scfdma is sometimes referred to as dftspread or dftprecoded ofdma. Ofdm transmitter modules as per wimax standard, read more. Following table summarizes difference between noma and ofdma. Both ofdm and ofdma are used in many modern wireless systems including acmimo radio, 802.