Ber performance of linear multiuser detectors in dscdma d. A cdma multiuser detection algorithm on the basis of belief propagation yoshiyuki kabashima department of computational intelligence and systems science, tokyo institute of technology, yo kohama 2268502, japan email. Independent component analysis ica aims to recover a set of unknown mutually independent source signals from theirs observed mixtures without knowledge of the mixing coefficients. Conference paper ieee pimrc95, on multiuser detection using a multivariable dfe. Independent component analysis in ds cdma multiuser detection and interference cancellation preliminary examination edition thesis for the degree of doctor of technolo gy to be presented with due permission for public examination and criticism in tietotalo building, auditorium tbxxx, at tampere. Independent component analysis in dscdma multiuser. Multiuser detection techniques for dscdma uwb system. Mmse linear multiuser detection for a dscdma system. On multipath channel estimation for cdma systems using multiple sensors. Interactive teaching of multiuser detection for ds cdma systems using matlab heng siong lim and wai kit wong multimedia university, faculty of engineering and technology, jalan ayer keroh lama, 75450 melaka, malaysia. Pdf of the ratio defined in the rtt conditioned on both the correct detection hy pothesis and erroneous detection. Sequence code division multiple access ds cdma system.
Neural network detection for mccdma signals in multipath. Interactive teaching of multiuser detection for dscdma. Decision feedback equalizer based multiuser detection in ds. Ber performance of linear multiuser detectors in dscdma. A method and device for processing a received signal by detecting within the received signal a plurality of possible symbols transmitted by or for a plurality k of users, each of the plurality of possible symbols belonging to a modulation constellation and being the subject of a spectral spreading by a spreading sequence. Iterative multiuser detection and decoding for dscdma. Ultrawidebanduwb is currently one of three new technologies of wireless communication. Hanzo, blockadaptive kernelbased cdma multiuser detection, in pr oc. On multipath channel estimation for cdma systems using. The present invention concerns a multiuser detection method and device. Nonlinear iterative multiuser detection and equalization. Introduction recently, directsequence codedivision multiple ac cess dscdma has become very popular in various applications such as optical and wireless communications 1, 2. Cdma multiuser delaytracking and detection wei zha and steven d.
Performance analysis of independent component analysis. Code division multiple access cdma works on the principle of code multiplexing and its advanced version, named as w cdma is the candidate for future land mobile networks. Multiuser detection deals with demodulation of the mutually interfering digital streams of information that occur in areas such as wireless communications, highspeed data transmission, dsl, satellite communication, digital television, and magnetic recording. Performance analysis of independent component analysis algorithms for multiuser detection of dscdma g. These suboptimal techniques have linear and nonlinear algorithms.
Direct sequence code division multiple accessdscdma is a method of multiplexing users by distinct codes and in this method all users use the same bandwidth. Nearoptimal multiuser detection in synchronous cdma using. In this paper, introduce linear multiuser detectors in direct sequence code division multiple access dscdma system. Multiuser detection is a technology that spawned in the early.
Ant colony input parameters optimization for multiuser detection in dscdma. Fastica, one of the ica methods, has been successfully applied in various fields. Multiuser detection mud is the intelligent estimationdemodulation of transmitted bits in the presence of multiple access interference mai. The research for new methods to reduce interference and increase efficien. Multiuser detection for synchronous dscdma in awgn. Iterative multiuser detection and decoding for dscdma system with spacetime linear dispersion pei xiao, member, ieee, jinsong wu, member, ieee, mathini sellathurai, senior member, ieee, t. Its detection techniques, broadly defined as multiuser detection, differ substantially from the conventional schemes. Cdma multiuser detection umd ece university of maryland. Abstractthe optimum receiver to detect the bits of multiple codedivison multiple access cdma users has exponential com plexity in the number of active. In code division multiple access cdma systems, blind multiuser detection mud techniques are of great importance, especially for downlinks, since in practice, it may be unrealistic for a mobile user to know the spreading codes of other active users in the channel.
Successive interference cancellation for multiuser. Mai occurs in multiaccess communication systems cdma tdma fdma where simultaneously occurring digital streams of information interfere with each other. Performance evaluation of a novel cdma detection technique. Channel parameter estimation and symbol detection for multiuser mimo mccdma systems. Therefore, it is important to design receivers suited for the asynchronous cdma systems.
Cdma, linear mmse detector, multiuser detector mud, mul. In multiuser detection of direct sequence code division multiple access ds cdma system, we proposes an improvedfastica algorithm to reduce multiple access interference mai. Mattila helsinki university of technology finland, otakaari 5a, 02150 espoo jari. Ltd, bangalore 560095, india department of electrical communication engineering indian institute of science, bangalore 560012, india.
In this paper, various detection techniques are studied in the synchronous case of a multiuser mccdma system operating in frequency selective. Non iterative algorithm for multiuser detection in dscdma system. Malmathanraj department of electronics and communication engineering national institute of technology nit, tiruchirappalli tamil nadu 620 015, india abstract. Engineering, national chunghsing university, taichung, taiwan.
Conference paper ieee icupc96, on equalizer design based on explicit channel models of dscdma systems. Direct sequence code division multiple access dscdma system is well known wireless technology. Multistage parallel interference cancellation pic technique gives good performance compared to successive interference cancellation sic method, but biased decision statistic and complexity problems are raised due to imperfect estimation of multiple access interference mai as number of stages increases. Multiuser detection mud is used to control multiple access interference mai and promote system performance and capacity, which is one of the key technology for cdma system. A pdakalman approach to multiuser detection in asynchronous cdma d. Multiuser detection is a technology that spawned in the early 80s. Us7349459b2 multiuser detection method and device in ds. Willett, senior member, ieee abstract the probabilistic data association pda method for multiuser detection in synchronous codedivision multipleaccess cdma communication channels is extended to asynchronous.
Multiuser detection for dscdma communications ieee. Minimum meansquared error multiuser decisionfeedback. Improved cdma detection techniques for future wireless systems. But the classical fastica does not converge quickly. Cavallaro and behnaam aazhang department of electrical and computer engineering,rice university ms 366, houston, tx 772511892 usa abstract this paper investigates methods to reduce the amount of computation needed to detect information bits using a. Cdma receiver algorithms tkk tietoliikennelaboratorio. Iterative multiuser detection and decoding for dscdma system. In a dscdma system, the objective of the receiver is to detect the transmitted information bits. Multiuser detection for synchronous dscdma in awgn channel md imraan department of electronics and communication engineering gulbarga, 585104. Xiao et al iterative multiuser detection and decoding for dscdma system 2345 veckkt.
As higher data rates are required, receiver design becomes a more and more important factor regarding the performance of the system. Analysis is to be carried out and simulations to be done keywords. Analysis is to be carried out and simulations to be done. Pdf blind multiuser detector for chaosbased cdma using. The use of multiple transmit and receive antennas has been proposed for the fourth generation codedivision multiple access cdma wireless cellular networks in. Ant colony input parameters optimization for multiuser. Furthermore, blind methods remove the need for training sequences which. This paper describes powercontrolled multi carrier and multiuser detection. Report which includes a derivation of the fractionally spaced simodfe. Multiuser detection for synchronous ds cdma in awgn channel md imraan department of electronics and communication engineering gulbarga, 585104. Optimum detection of cdma amit kumar dutta oregon state university, corvallis, or, usa abstract here we describe methods of detection of code division multiple access signal against gaussian noise. Multiuser detection in dscdma system using biogeography based optimization. Multiuser detection and channel estimation for dscdma systems.
Independent component analysis in dscdma multiuser detection and interference cancellation preliminary examination edition thesis for the degree of doctor of technolo gy to be presented with due permission for public examination and criticism in tietotalo building, auditorium tbxxx, at tampere. An improved linear mmse detection technique for multicarrier. This system suffers from mai multiple access interference caused by direct sequence users. Thereafter, in order to use the same frequency, users, which are in the same zone or cell, can adopt a tdma or cdma multiple access etc. Denoting g vec vec at 1 vec at 2 vec at q w k jw1j w2j wq k j t we can now express the jth ldc codeword of the kth user in vector form as x kjvec w kjt g vecw kj 3 where the. Channel parameter estimation and symbol detection for. Carrier sense multiple access with collision detection csmacd by dinesh thakur category. Strom, senior member, ieee abstractthis paper considers a qary orthogonal direct. Nemade associate professor, electronics and telecommunication engineering, gvaiet mumbai mahesh t kolte professor, department of electronics and telecommunication engineering, mit college of engineering, pune abstract. Csmacd is a protocol in which the station senses the carrier or channel before transmitting frame. Multiuser detection mud is the intelligent estimationdemodulation of.
Linear multiuser detection algorithm for multiaccess interference suppression or even elimination has certain results. Multiuser detection technique is mainly used to eliminate multiple access interferencemaiin dscdma uwb communication systems. Independent component analysis in dscdma multiuser detection. This paper focuses on the design of a multiuser receiver structure for the reverse link of a codedivision multipleaccess communication system, in the presence of multipath effects and using an antenna array at the base station receiver. But for a fixed decision threshold is set to 0, the detection performance of linear multiuser detection algorithm will be decreased significantly. Conventional cdma receivers rake do not take into account the multiple access interference mai caused by other users. Abstract multicarrier transmission technology has shown tremendous potential in realizing high data rates for next generation broadband wireless communication systems.
Non iterative algorithm for multiuser detection in ds cdma system. It is also being currently investigated for demodulation in lowpower interchip and intrachip communication. Index terms codedivision multiple access cdma, decision feedback, interference cancellation, interference suppression, multiuser detection. Simulations show that the ekf channel estimator performance is improved when the qrdm algorithm is used instead of the. However, it is well known that the conventional cdma receiver does suffer from serious problems. Non iterative algorithm for multiuser detection in dscdma. A cdma multiuser detection algorithm on the basis of. Joint detection and channel estimation algorithms for qscdma. Multiple access to reduce the impact of collisions on the network performance, ethernet uses an algorithm called csma with collision detection csma cd. Code division multiple access cdma is one of the several methods of multiplexing wireless users 1. Decision feedback equalizer based multiuser detection in ds cdma systems m. Ant colony input parameters optimization for multiuser detection in dscdma systems.
Decision feedback equalizer based multiuser detection in dscdma systems m. In this paper, introduce linear multiuser detectors in direct sequence code division multiple access ds cdma system. This performance degradation caused by mai can be overcome using multiuser detection where information about the other users is used in detection. Ofdm orthogonal frequency division multiplexing pdf probability. Interactive teaching of multiuser detection for dscdma systems using matlab heng siong lim and wai kit wong multimedia university, faculty of engineering and technology, jalan ayer keroh lama, 75450 melaka, malaysia. Apr 20, 2005 performance evaluation of a novel cdma detection technique. Performance analysis of independent component analysis algorithms for multiuser detection of ds cdma g.
Performance comparison of spreading codes in linear multi. Neural network is used as a frontend stage of one stage pic circuit. The selection of a good code is important, because autocorrelation properties and length of the code sets bound on the system capacity. Multiuser detection for dscdma communications ieee communications ma gazine author. We transmit differentially encoded signal and in the receiver, we do signal processing to reduce noise injected by the mixer or rf front end. Hasegawa, member, ieee abstract a probabilistic data association pda method is proposed in this letter for multiuser detection over synchronous. Therefore a kind of multiuser detection with preprocessing has been researched. Multiuser detection of dscdma based on improvedfastica. Conference paper at the swedish radio conference on the same theme.
Support vector machine multiuser receiver for dscdma signals in. Volume 39, issue 17, 1 december 2012, pages 1287612884. 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. Multiuser detection with neural network and pic in cdma.
In this paper, multiuser detection in code division multiple access cdma was performed by using neural network nn and parallel interference cancellation pic. Powercontrolled multicarrier and multiuser detection. Chockalingam wireless and broadband communications synopsys india pvt. More particularly, the present invention concerns a maximum likelihood multiuser detection method and device for a ds cdma direct sequence code division multiple access telecommunication system. Aug 18, 2014 multistage parallel interference cancellation pic technique gives good performance compared to successive interference cancellation sic method, but biased decision statistic and complexity problems are raised due to imperfect estimation of multiple access interference mai as number of stages increases.
Code division multiple access cdma linkedin slideshare. Nearoptimal multiuser detection in synchronous cdma using probabilistic data association j. In 1985, the fcc allocated three frequency bands to spread spectrum communications. Ltd, bangalore 560095, india department of electrical communication engineering indian institute of. Fast multiuser detector for a timevarying cdma system. The use of code division multiple access cdma makes thirdgeneration wireless systems interference limited rather than noise limited.
Channel parameter estimation and symbol detection for multiuser mimo mc cdma systems. Carrier sense multiple access with collision detection csmacd. Interference and complexity reduction in multistage multi. Introduction multiuser detection has been proposed as a way to increase the spectral efficiency of codedivision multipleaccess cdma systems.
Cdma code division multiple access or cdma has its roots in wwii era spread spectrum technology. Code division multiple access cdma works on the principle of code multiplexing and its advanced version, named as wcdma is the candidate for future land mobile networks. Non iterative algorithm for multiuser detection in ds. It has now developed into an important, fullfledged field in multiaccess communications. Gaussian processes for multiuser detection in cdma receivers. Cdma can be implemented in several ways, two of which are frequency hopping and direct sequencing. A pdakalman approach to multiuser detection in asynchronous. Also, each user is allocated the entire frequency spectrum for transmission. Decision feedback equalizer based multiuser detection in.
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