Ofdm, also known as multicarrier transmission or modulation, uses multiple carrier signals at different frequencies, sending some of the bits on each channel. In this project we will use c language to design a multi carrier cdma com. Multicarrier codedivision multiple access mccdma is a multiple access scheme used in. An overview of research on multicarrier modulation, ofdm and mccdma. Scfde can be viewed as a linearly precoded ofdm scheme, and scfdma can as a linearly precoded ofdma scheme, henceforth lpofdma. I multiuser detection for adaptive singlecarrier cdma. Division multiple access mccdma and multicarrier spread spectrum workshop, november 2006. Singlecarrier fdma scfdma is frequencydivision multiple access scheme. The single carrier transmission means one radio frequency carrier is used to carry the information. It maps each bit to all subcarriers, but each subcarrier uses a timeconstant phase offset according to a code pattern. What is the main difference between single carrier and.
All user signals can easily be synchronized, and all signals on one subcarrier experience the same radio channel properties. It is a multiuser version of single carrier frequencydomainequalization scfde modulation scheme. Time spreading, synchronisation, networking and standards. That is, each user symbol is carried over multiple parallel subcarriers, but it is phaseshifted according to a code value. Currently, a technical indepth book on this subject, which has a similar detailed exposure of the recent advances in cdma, mary cdma and mc cdma, is unavailable.
Multicarrier and spread spectrum systems is one of the first books to describe and. A channel estimation, equalization and powercontrol procedure is a necessary part of the dscdma system which makes the receiver more complex to design. The code values differ per subcarrier and per user. Multicarrier codedivision multiple access 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.
Multicarrier codedivision multiple access wikipedia. The capacity of a dscdma system is limited by multiuser interference. The mc cdma transmitter for a single user is shown in figure 1. Mccdma spreads each user symbol in the frequency domain. Multi carrier code division multiple access mc cdma technique is a special form of multi carrier modulation technique that has the ability to support high data rate multimedia applications.
The receiver combines all subcarrier signals, by weighing t. Based on the combination of multicarrier modulation and spread spectrum. Iii performance analysis of mccdma systems with single user detection techniques. This idea can further be exploited if a special form of cdma transmission is used, which is the fourier transform of direct sequence cdma called multi carrier cdma, see below and 9, 10. Tirrenia workshop on digital communications, tirrenia, italy. I multiuser detection for adaptive singlecarrier cdma 29.
Multicarrier code division multiple access mccdma technique is a special form of multicarrier modulation technique that has the ability to support high data rate multimedia applications. The multi carrier cdma system is a novel 3rd generation mobile communication system. 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 ofdma. This volume is dedicated to a range of cdma and mc cdma transmission aspects of systems designed for communicating over fading wireless channels. A further attraction of the joint treatment of these topics is that it allows the. Hence information in the form of bits is carried by one single rf carrier.
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