Figure2 depicts the block diagram of sc fdma and ofdma system. Oct 05, 2016 ofdmasc fdma in 4g lte part 2 streams of data, in the form of bits, reaches network gateway from various sources. Scfdma has drawn great attention from the communications industry as an attractive alternative to orthogonal frequency division multiple access ofdma. 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. One of the key parameters that affects all mobiles is that of battery life. As shown in the figure in sc fdma one extra module dft is added before ifft module in the transmitter chain and idft is added in the receiver chain. To complete sc fdma signal generation, the process follows the same steps as for ofdma.
Pdf single carrier fdma for next generation communication. Scfdma can be viewed as a special ofdma system with the users signal preencoded by discrete fourier transform dft, hence also known as dftprecoded ofdma or dftspread ofdma. Scfdma and lte uplink physical layer design burcu hanta 02. Sc fdma transmitter incorporate fft module before subcarrier mapping. The only difference is the presence of the dft in sc fdma. Fdma which utilizes single carrier modulation at the transmitter and frequency domain equalization at. An introduction to lte systems is presented in this manuscript. If they are equal, they simply cancel out and it becomes a conventional singlel user single carrier system with frequency domain equalization. High papr requires expensive and inefficient power amplifiers with high requirements on linearity. Oct 31, 2008 scfdma has drawn great attention from the communications industry as an attractive alternative to orthogonal frequency division multiple access ofdma. As discussed in my previous post, in an ofdm system the data to be transmitted, x0, x1, xn1, is first modulated, typically using. Ofdm and scfdma lectures lte long term evolution medium. Introduction to single carrier fdma places scfdma in the wider context of wireless communications, providing the reader with an indepth tutorial on scfdma technology.
Orthogonal frequency division multiplex ofdm tutorial 1 intuitive guide to principles of communications orthogonal frequency division multiplexing ofdm modulation a mapping of the information on changes in the carrier phase, frequency or amplitude or combination. From both a technical and practical point of view, there is much to understand, examine and evaluate in the capabilities and bene. Introduction to single carrier fdma places sc fdma in the wider context of wireless communications, providing the reader with an indepth tutorial on sc fdma technology. It has a similar structure and performance as ofdm. Overview long term evolution lte is the next step forward in cellular 3g services. Sc fdma peaktoaverage power ratio papr ifdma interleaved fdma distributed sc fdma lfdma localized fdma localized sc fdma qpsk 16qam source. Scfdmsc fdma for scenarios requiring high energy efficiency e. Figure 2 illustrates the concepts of ofdma and sc fdma.
The main focus is on the singlecarrier frequency division multiple access sc fdma scheme which has been selected as the multipleaccess scheme of the lte uplink. The present document aims at assessing the performance of a sc fdma based radio waveform over geostationary satellites in kuka band. Scfdma is a hybrid modulation scheme that combines the low peaktoaverage ratio par of traditional singlecarrier formats such as gsm with the multipath. I think this is a very good qualitative comparison between ofdma and sc fdma. One prominent advantage over ofdma is that the sc fdma signal has lower peakto. Dvbs2, dvbs2x and dvbrcs2, focusing on the radio and physical layers. The reverse is taken care in the receiver part of sc fdma compare to either ofdm or ofdma technique.
Single carrier frequency division multiple access sc. 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 video tutorial part 2 single carrier this video explains the importance of scfdma single carrier fdma and uplink frame structure in lte. An introduction to sc fdma used by lte in uplink direction both wimax and the umts successor technology lte use orthogonal frequency division multiplexing ofdm as the core modulation technology on the air interface in downlink direction.
For practicality, scofdma is implemented in lte using a discrete fourier transform spread ofdm transmission dftsofdm which is commonly referred to as a frequencydomain generalization of sc fdma. If they are equal, they simply cancel out and it becomes a conventional singlel user single carrier system with frequency domain. Pdf performance enhancement of scfdma systems using a. Pdf lte for umts ofdma and scfdma based radio access. Performance evaluation of lte physical layer using scfdma. The receiver performs the npoint fft to extract the individual subcarriers. Lte uses a precoded version of ofdm called single carrier frequency division multiple access sc. Scfdma is not as sensitive to frequency instability and doppler effect as. Goodman scfdma for uplink wireless transmission, ieee vehicular technology magazine, september 2006 localized mode lfdma is used in lte.
Llttee qquuiicckk gguuiiddee llttee oovveerrvviieeww lte stands for long term evolution and it was started as a project in 2004 by telecommunication body known as the third generation partnership project 3gpp. Block diagram view of the scfdma modulation and propagation channel models and associated functions in the lte toolbox. The following topics are covered ofdm and sc fdma lectures is published by eventhelix in lte long term evolution. It is not possible to use ofdma on the uplink since, as told before, it presents a high peaktoaverage power ratio. Introduction to sc fdma and uplink frame structure. The sc fdma signal, which is almost always narrower than the channel bandwidth, can be positioned anywhere in the channel bandwidth, thus executing the frequency division multiple access fdma essential for efficiently sharing the uplink between multiple users.
Segal, tutorial on multiaccess ofdm ofdma technology. Peak to average power ratio papr comparison with sc fdma and ofdma. Sc fdma modulation sc fdma is a new multiple access technique that utilizes single carrier modulation, dftspread orthogonal frequency multiplexing, and frequency domain equalization. Ofdm and sc fdma video lectures cover ofdm and sc fdma is great detail. The main focus is on the singlecarrier frequency division multiple access scfdma scheme which has been selected as the multipleaccess scheme of the lte uplink. Ledalab matlab software for analysis of skin conductance data sc. Pdf the main aim of this work is to investigate the performance of single carrier frequency division multiple access scfdma in mobile.
Sc fdma was used in view of the fact that its peak to average power ratio is smaller than for ofdma the lower peak to average power ratio enabling better levels of final rf power amplifier to be achieved this was and is an important factor for mobile handset battery life. Goodman sc fdma for uplink wireless transmission, ieee vehicular technology magazine, september 2006 localized mode lfdma is used in lte. On sc fdma before applying the ifft the symbols are pre coded by a dft discrete fourier transform. Performance enhancement of scfdma systems using a companding technique article pdf available in annals of telecommunications annales des telecommunications 655. Sc fdma and lte uplink physical layer design burcu hanta 02. Scfdma with index modulation for m2m and iot uplink applications.
Although still using a form of ofdma technology, the implementation is called single carrier frequency division multiple access sc fdma. Apr 05, 2010 the effect of isi inter symbol interference is suppressed by virtue of a longer symbol period of the parallel ofdm subcarriers than a single carrier system and the use of cyclic prefix cp explained later. Support for vehicular mobility and asymmetrical link. Frequency division multiple access ofdma in downlink dl and single carrier frequency division multiple access sc fdma for uplink ul, as shown in figure 3. Sc fdma means single carrier frequency division multiple access and ofdm means orthogonal frequency division multiplexing. Sc fdma modulation singlecarrier frequency division multipleaccess modulator, demodulator, dimension information lte uplink transmission uses singlecarrier frequency division multipleaccess modulation. Overview of the 3gpp long term evolution physical layer. This is to compensate for a drawback with normal ofdm, which has a very high peak to average power ratio papr. Following is the block diagram of typical sc fdma system. These are interesting times because it is rare that the communications industry rolls out a new modulation format. Moreover, it aims at defining an evaluation framework for performance comparison with existing waveform technologies e. Sc fdma discrete fourier transform precoded ofdma receiver at the base station. Lte video tutorial part 2 single carrier this video explains the importance of scfdma single carrier fdma and uplink frame. Sc fdma singe carrier fdma presents the benefit of a single carrier multiplexing of having a lower peaktoaverage power ratio.
This thesis focuses on these two transmission techniques and implements a sc fdma prototype in the gnuradio platform. Equalization and carrier frequency offsets compensation. December 2009 abstract the long term evolution lte physical layer design is covered as the main topic in this report. As mentioned dft before ifft of ofdma and idft after dft of ofdma system make it sc fdma. Scfdma uplink transmissions for cellular iot and machine tomachine m2m networks. Introduction to single carrier fdma ieee conference. Figure mentions modules unique to the sc fdma and in common with ofdma system. Sc fdma has drawn great attention from the communications industry as an attractive alternative to orthogonal frequency division multiple access ofdma. Scfdma fundamental single carrierfdma is a recently developed single carrier multiple access technique which has similar structure and performance to ofdma. Today, well talk about scfdma, or singlecarrier frequencydivision multiple access. Equalization and carrier frequency offsets 115 signal model for the uplink dftsc fdma and the uplink dctsc fdma systems in the presence of cfos and also derive an. Scfdma versus ofdma department of electrical communication.
For this reason sc fdma is sometimes referred to as dftspread or dftprecoded ofdma. This section of matlab source code covers sc fdma basics and mention basic matlab code. Sc fdma in practice, sc fdma is implemented as if the user is allocated a contiguous subset of subcarriers transmitter at the user terminal. Introduction to orthogonal frequency division multiplexing ofdm cyclic prefix cp and circul. The remainder of this paper is organized as follows. For the lte uplink, a different concept is used for the access technique. This is followed by equilization and an mpoint ifft to recover the single carrier that was carried over msubcarriers in the nsubcarrier system. Implementing the scfdma transmission technique using. Singlecarrier fdma sc fdma is a frequencydivision multiple access scheme.
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. Sc fdma is currently adopted as the uplink multiple access scheme for 3gpp lte. Performance evaluation of lte physical layer using sc. This page compares sc fdma vs ofdm and mentions difference between sc fdma and ofdm modulation techniques sc fdma means single carrier frequency division multiple access and ofdm means orthogonal frequency division multiplexing as shown in the figure in sc fdma one extra module dft is added. Scfdma peaktoaverage power ratio papr ifdma interleaved fdma distributed scfdma lfdma localized fdma localized scfdma qpsk 16qam source. 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 sc fdma single carrier frequency division multiple access. Single carrier frequency division multiple access sc fdma which utilizes single carrier modulation at the transmitter and frequency domain equalization at the receiver is a technique that has similar performance and essentially the same overall structure as those of an ofdma system.
Muhamed, fundamentals of lte, prentice hall, 2010, isbn. Pdf scfdma single carrier frequency division multiple access also known as dft spread fdma is a modified form of ofdma orthogonal. An introduction to scfdma used by lte in uplink direction. For practicality, sc ofdma is implemented in lte using a discrete fourier transform spread ofdm transmission dftsofdm which is commonly referred to as a frequencydomain generalization of sc fdma. Sae systemarchitectureevolution is the corresponding evolution of the gprs3g packet core network evolution. If you specify the windowing field in ue, the function ignores it, and the output windowing field of info is as specified in windowing. Today, well talk about sc fdma, or singlecarrier frequencydivision multiple access. 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. Sc fdma has been adopted as the airinterference for the uplink of the lte and ltea systems. Scfdma was chosen since it combines the low papr techniques of single carrier transmission systems, such as gsm and cdma, with the multipath resistance.
Like other multiple access schemes tdma, fdma, cdma, ofdma, it deals with the assignment of multiple users to a shared communication resource. Expected in the 2008 time frame, lte is a 3gpp standard that provides for an uplink speed of up to 50 megabits per second mbps and a downlink speed of up. Scqam in evdo, umts low papr at low spectral efficiency allow asynchronous multiplexing simple waveform synthesis limited flexibility in spectral assignment nontrivial support for mimo scfde equivalent to scqam with cp allow fde processing similar as scqam aclr similar to dftspread ofdm scfdm1 in lte uplink. The detailed specification of lte is given in table 1.