May 04, 20 thus it might be useful to implement higher bit rates with multicode cdmasystems 23. Thus it might be useful to implement higher bit rates with multicode cdmasystems 23. Code division multiple access cdma is a digital cellular technology used for mobile communication. However,giventhe consumersthirst for higher bit rates, during the early 1990sthe researchcommunity turned its attention to developing the third generation 3g system, which was also based on various cdma solutions. Specifically, linear as well as nonlinear multi user detectors are considered. Linnartz, performance analysis of synchronous mccdma in mobile.
Multiple users occupying the same band by having different codes is known as cdma code division multiple access system let w spread bandwidth in hz r 1tb date rate s received power of the desired signal in w j received power for undesired signals like multiple access users, multipath. Mccdma is a modulation method that uses multicarrier transmission more precisely ofdm of dscdmatype signals. Multi carrier cdma multi carrier code division multiple access mc cdma is a relatively new concept. Satya prasad majumder in partial fulfillment of the requirements for the degree of bachelor of science in electronics and communication engineering. Cdma2000, also known as imt cdma multi carrier, is a codedivision multiple access cdma version of the imt2000 standard developed by the itu. Ormondroyd, multicarrier cdma using convolutional coding and interference cancellation over fading channels, first workshop on multicarrier spreadspectrum, oberpfaffenhofen, germany, april 1997, pp 8996. One appropriate mean to increase spectral efficiency of cdma systems is multi user detection. Performance comparison of multicarrier cdma using qpsk and. In this paper, we introduce a novel merger of a single smart antenna array and mc cdma multi carrier code division multiple access systems. Multicarrier evdo rashid attar, donna ghosh, chris lott, mingxi fan, peter black, ramin rezaiifar, parag agashe abstract the evolution of cdma2000 1xevdo systems to multicarrier evdo supported by 1xevdo revision b is discussed in this paper.
This paper gives an overview of different multi user detection techniques and compares them with the conventional singleuser detection including channel coding. If tmobile and sprint merge, what is the best strategy to. Cdma is widely deployed by carriers in north america, as well as in korea, japan, china, south america, and australia. Cdma can be implemented in several ways, two of which are frequency hopping and direct sequencing. Mccdma is a modulation method that uses multicarrier transmission more precisely ofdm of. Multicarrier codedivision multiple access wikipedia. Ofdm and the combination of ofdm with code division multiple access cdma. Multiple access interference in multicarrier cdma t. Multicarrier cdma mccdma 7 is the combination of cdma and ofdm, results better frequency diversity and high data rates. The receiver, knowing the code sequence of the user, decodes the received signal and recovers the original data. Singal professor, school of electronics and electrical engineering, chitkara university, punjab, india abstract multi carrier code division multiple access mc cdma technique maintains the original signaling interval while it spreads the signal over wide bandwidth like directsequence code. Multi carrier cdma uses another way of spreading while is95 uses a.
Code division multiple access cdma is a sort of multiplexing that facilitates various signals to occupy a single transmission channel. But is there really a good roi if bb gets a phone ready for some small cdma carrier in, say, the southeast uswhen the metrics point to a lack of interest for bb phones in the carriers customers. Probability density function pdf of x modx modulo of x argmin x ffxg value of xfor which fx has the minimum value. Pdf many digital cellular and mobile systems are in use today. Performance comparison of multicarrier cdma using qpsk. Turbo codeddiversity combining scheme for hybrid dssfh cdma systems. As there are only seven paging channels for each carrier in a multi carrier cdma system, therefore the existing system cant search more than seven users at a time. Digital multicarrier spread spectrum versus direct sequence spread spectrum for resistance to jamming and multipath shengli zhou, student member, ieee, georgios b. Similar to singlecarrier cdma systems, the users are multiplexed with orthogonal codes to distinguish users in mccdma 3. Most of the codes provide high reliability but have a low data rate. Singal professor, school of electronics and electrical engineering, chitkara university, punjab, india abstract multicarrier code division multiple access mccdma technique maintains the original signaling interval while it spreads the signal over wide bandwidth like directsequence code. The multicarrier cdma system is a novel 3rd generation mobile communication system.
Both systems are based on a cellular concept, all users and so all interferers are synchronized with each other. Mc cdma is praised as a modulation solution that merges the insights due to. Multiple access interference in multi carrier cdma t. Ofdm technique for multicarrier modulation mcm signaling page no. Multi carrier modulation multi carrier modulation mcm is the principle of transmitting data by dividing the stream into several bit streams, each of which has a much lower bit rate, and by using these substreams to modulate several carriers.
International journal of computer trends and technology. Multi carrier code division multiple access mccdma, 978. The whole mccdma system is composed of 5 main components which are the compressor, transmitter model, channel model, receiver model and decompressor. Similar to single carrier cdma systems, the users are multiplexed with orthogonal codes to distinguish users in mc cdma 3. Multicarrier digital communications theory and applications.
However,giventhe consumersthirst for higher bit rates, during the early 1990sthe researchcommunity. Cdma 2000 is mostly an orthogonal cdma system gold sequences have only three crosscorrelation peaks, which tend to get less important as the length of the code increases. Basic note on spread spectrum cdma signals 7 shiftregister sequences and gold code. Cdma is the base on which access methods such as cdmaone, cdma2000, and wcdma are built. Chapter 7 multiple division techniques outline frequency division multiple access fdma time division multiple access tdma code division multiple access cdma comparison of fdma, tdma, and cdma walsh codes nearfar problem types of interferences analog and digital signals basic modulation techniques amplitude modulation am frequency modulation fm. The spread spectrum signal, from a cdma system, has a very low power spectral density and, therefore, a cdma system can overlay on top of existing narrowband mobile cellular systems of the same frequency band. At their peak, bb used to have phones for us cellular and boost mobile. Several multiaccess schemes that combine multicarrier techniques and cdma have been proposed e. The core principle of spread spectrum is the use of noiselike carrier waves, and, as the name implies, bandwidths much wider than that required for simple pointtopoint communication at the same data rate. This paper gives an overview of different multiuser detection techniques and compares them with the conventional singleuser detection including channel coding. When a unit is about to leave one cell area and travel to another it seeks out the strongest cell signal it can find. These two technologies differ in the way calls and data travel over the mobile phone networks. Multicarrier and spread spectrum systems is one of the first books to describe and analyze the basic concepts of multicarrier ofdm transmission and its combination with spread spectrum mccdma. Multi carrier code division multiple access mccdma is a relatively new.
Gold sequences are in useful in nonorthogonal cdma. Pdf the authors present an overview of new multiple access schemes. Multi carrier code division multiple access mc cdma, based on a combination of cdma and orthogonal frequency division multiplexing ofdm, is a major candidate for the transmission technology of the forthcoming 4th generation mobile communication system. The higher data rate can be achieved with the use of multi carrier system such as ofdm. Mc cdma spreads each user symbol in the frequency domain. What is cdma2000 imtcdma multicarrier or codedivision. The bandwidth of the coded data signal is chosen to be much larger. Cdma cellular systems are deemed superior to fdma and tdma, which is why cdma plays a critical role in building efficient, robust, and.
Future mobile communication system requires high data rate and good quality of service to consumers. Cdma architecture soft handoff hard handoff are defined as the milliseconds in which a mobile unit is passed from one cell to the other and there is no connection. The most common standards of 1g and 2g used in different parts of world. To combat, multicarrier code division multiple access mccdma is a favorable technique for achieving higher data rates along with reduced intersymbol interference isi and easy access to. The multi carrier cdma system is a novel 3rd generation mobile communication system. In second and third generation wireless communication a. One appropriate mean to increase spectral efficiency of cdma systems is multiuser detection. Concept i is referred to as mccdma, also known as ofdmcdma or. Powercontrolled multicarrier and multiuser detection. Rashid attar, donna ghosh, chris lott, mingxi fan, peter. And these modes are both operating at different frequencies. The summary of 1g and 2g mobile standards are given in table1. Performance analyses of multi carrier ds cdma wireless communication systems saimoon ara amin id.
Multicarrier cdma using interference cancellation springerlink. Its development aimed at improved performance over multipath links. Mccdma is praised as a modulation solution that merges the insights due to. The technology is commonly used in ultrahighfrequency uhf cellular telephone systems, bands ranging between the 800mhz and 1. Cdma is a form of spreadspectrum, a family of digital communication techniques that have been used in military applications for many years. Therefore, orthogonal frequency division multiplexing ofdm is one of the leading candidates for future wireless systems. This paper describes powercontrolled multi carrier and multiuser detection. Multicarrier code division multiple access mccdma, based on a combination of cdma and orthogonal frequency division multiplexing ofdm, is a major candidate for the transmission technology of the forthcoming 4th generation mobile communication system. Multicarrier modulation, orthogonal frequency division multiplexing ofdm particularly, has been successfully applied to a wide variety of digital communications applications over the past several years. Performance of multicarrier cdma in frequencyselective fading. Multicarrier cdma uses another way of spreading while is95 uses a combination of a walshsequence and a shiftregister sequence to enable synchronization. It is done by duplicating the paging message for each of the paging channels on multicarrier system. Multi carrier modulation, orthogonal frequency division multi plexing ofdm particularly, has been successfully applied to a wide variety of digital communications applications over the past several years. The different architectures and detection strategies as well as basebandrelated transceiver components are explained.
Multicode code division multiple access in this section the capability of wts to transmitand receive on multiple cdma channels by the means of mccdma is discussed. Digital multicarrier spread spectrum versus direct. Sprints current lte phones have gsmhspa antennas for world use. Ofdm technique for multicarrier modulation mcm signaling. Cdma dscdma, the merger of which has led to mccdma. Multi carrier cdma mc cdma two main variations of the mc spread spectrum systems are the mc cdma frequency domain spreading and mc direct sequence cdma mcds cdma time domain spreading. Specifically, linear as well as nonlinear multiuser detectors are considered.
Cdma2000, also known as imtcdma multicarrier, is a codedivision multiple access cdma version of the imt2000 standard developed by the itu. Multi carrier codedivision multiple access mc cdma is a multiple access scheme used in ofdmbased telecommunication systems, allowing the system to support multiple users at the same time over same frequency band. Cdma code division multiple access or cdma has its roots in wwii era spread spectrum technology. Orthogonal frequency division multiplexing ofdm is one of such multicarrier techniques which have attracted. Difference between gsm and cdma the worlds renowned mobile phone network technologies are gsm global system for mobile communication and cdma code division multiple access. Multicarrier cdma multi carrier code division multiple access mccdma is a relatively new concept. Merging multicarrier cdma and oscillatingbeam smart. Dscdma, where ofdm was chosen for broadcast applications dvb, dab as well as for broadband wireless indoor standards etsi hiperlanii, ieee802.
Sprint is looking to merge with tmobile, but combining their two networks is not going to be an easy fit. In 1985, the fcc allocated three frequency bands to spread spectrum communications. Then the signal is multiplied by the carrier which is the second modulation. One way of looking at mccdma is as a combination of cdma and ofdm, resulting in better frequency diversity and higher data rates. Digital multicarrier spread spectrum versus direct sequence.
Grouporthogonal multicarrier cdma digital technology center. The objective of the paper is to provide a survey on multi carrier transmission techniques i. Performance analyses of multicarrier dscdma wireless communication systems saimoon ara amin id. Code division multiple access cdma the concept of signal spreading and its uses in communications lets take a stright forward binary signal of symbol rate 2. Multicarrier cdma is a digital modulation technique where a single data symbol. In this project we will use c language to design a.
One way of looking at mc cdma is as a combination of cdma and ofdm, resulting in better frequency diversity and higher data rates. In this project we will use c language to design a multi carrier cdma com. Here, all carriers in the mc cdma system are applied. The objective of the paper is to provide a survey on multicarrier transmission techniques i. Mc cdma is a modulation method that uses multi carrier transmission more precisely ofdm of ds cdma type signals. Intelligent paging strategy for multi carrier cdma system. Giannakis, fellow, ieee, and ananthram swami, senior member, ieee abstract we compare single user digital multicarrier spread spectrum mcss modulation with direct sequence.
So during optimization how tool decides which mode to take first if we merge both constraints in a single sdc. However,giventhe consumersthirst for higher bit rates, during the early 1990sthe researchcommunity turned its attention to developing the third generation 3g system, which was also based on. This page covers multicarrier cdma tutorial which include cdma and ofdm modulationmultiple access techniques. Ofdm makes use of fourier bases while wpmcm uses wavelet packet bases. Hence, it is clear that the codes with high rate and reliability are the design target in minds of most researchers.
The motivation behind maximal ratio combining is that the components of the. They also have a single autocorrelation peak at zero, just like ordinary pn sequences. In this paper, we merge the advantages of ofdma and cdma to minimize mui effects, and also enable the maximum available diversity for every user. Multicarrier cdma mccdma two main variations of the mc spread spectrum systems are the mccdma frequency domain spreading and mc direct sequence cdma mcdscdma time domain spreading. Multicarrier modulation multicarrier modulation mcm is the principle of transmitting data by dividing the stream into several bit streams, each of which has a much lower bit rate, and by using these substreams to modulate several carriers. The cdma2000 standard is an aspect of thirdgeneration 3g mobile wireless technology. Code division multiple access cdma system in multipath environment.
Although ofdm has been chosen as the physical layer standard for a diversity of important systems, the theory, algorithms. Cdma technique has been considered to be a candidate to. Multicarrier cdma tutorial mccdma multi carrier cdma. An overview of multicarrier cdma article pdf available in ieee communications magazine 3512. Multicarrier codedivision multiple access mccdma is a multiple access scheme used in ofdmbased telecommunication systems, allowing the system to support multiple users at the same time over same frequency band. This is because the interference due to cdma signals, added to a narrowband mobile system channel, is very low and, therefore, the presence of cdma signal will hardly aect the performance of the. Multi carrier code division multiple access mccdma, 9783838305868, this book focuses on image transmission through mccdma channel in low snr environment.
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