Word Files
Reference for Downloading Educational Files
  2. Telecommunication Engineering
  3. Investigating and extracting centralized and decentralized multi-user detection algorithms and comparing their efficiency

Investigating and extracting centralized and decentralized multi-user detection algorithms and comparing their efficiency

Number of pages: 94 File Format: word File Code: 32176
Year: 2012 University Degree: Master's degree Category: Telecommunication Engineering
Tags/Keywords: Blind detection - Detection algorithms - Fuzzy control method - Radio waves - signal - V-BLAST - Wireless communication equipment
  • Part of the Content
  • Contents & Resources

  • Summary of Investigating and extracting centralized and decentralized multi-user detection algorithms and comparing their efficiency

    Master's thesis in the field of electricity-telecommunication system

    Abstract

     

     

    In this thesis, we examine commonly used methods to reveal information in signals that are the result of signals that are the result of different users in a system. They have sent multi-user telecommunications. According to the nature of this problem, it can be divided into two main parts: revealing the information sent by all users whose sent signal is included in the received result signal, which is referred to as centralized detection, and also revealing the information sent by a particular desired user from among the users who have sent a signal, which is known as decentralized detection. In this thesis, common methods of both types of detection are examined. In the first case, we examine the optimal detector, and we also examine the spherical detector for its implementation. Then we examine the following optimal methods and introduce the uncorrelated detector [1], the least mean square error detector [2], the upper triangular matrix detector and the V-BLAST detector. In the second case, we examine the adaptive receivers that perform the detection operation by finding training fields [3]. Also, we will introduce common methods for blind detection of such signals in which there is no need to receive training courses. In the latter case, we will present a method that we have introduced according to the adaptive nature of the introduced blind detectors using the fuzzy control method [4] to determine the appropriate step size [5], which leads to the improvement of the performance of the introduced blind detection.      

    1-1- Introduction

    The use of radio waves to send information from one point to another has been exploited for more than a century. Although commercial and military telecommunications systems have been in operation for decades, the past decade has seen unprecedented growth in demand for personal wireless telecommunications equipment.  This unprecedented growth is the result of the advances that have occurred in the design of electronic circuits and the technology of integrated circuits, which has made it possible to make telecommunications transmitters and receivers very small and portable, and at the same time reduce their cost to a reasonable extent. Also, in recent years, with the advances in the design of low-power circuits and further growth in miniaturization technologies [1], the ground has been prepared for the emergence of more versatile wireless telecommunication equipment [2] in the market, which are able to implement and provide applications that require sending and receiving information at a high rate. 

    The popularity of using handheld telecommunication equipment with various information and multimedia capabilities on the one hand and the limitation of telecommunication resources [3] such as bandwidth, time and power on the other hand, has caused us to need to provide new telecommunication systems in which we can accommodate and serve more users at the same time and at the same time we can also provide the appropriate bandwidth to cover their various communication needs. Provide as soon as requested [4]. Therefore, to respond to these two needs, a suitable multi-user system should be designed. Generally, to create a multi-user telecommunication system and allocate telecommunication resources among multiple users, various methods such as multiple access with frequency division [5] FDMA, multiple access with time division [6] TDMA and multiple access with code division [7] CDMA are used. take [1]. We will continue to introduce these methods.

    1-2- Multiple access methods

    There are various methods for allocating telecommunication resources among multiple users, whose purpose is to provide proper service to all covered users on the one hand, and on the other hand, to minimize their interference effect on each other. 

    1-2-1- FDMA frequency division multiple access method

    The emergence of radio frequency modulation in the early 20th century allowed radio transmissions to exist at the same time and place without interfering with each other. This was possible by using different carrier frequencies [8]. This idea was also used in long-distance wire telephone systems. Multiple access with frequency division assigns a different carrier frequency to each user so that the resulting spectrum is without overlap between different transmitters (Figure 1).  

    In this method, any of the available channels or users can be reached by using cross-pass filtering.

    From the implementation point of view, due to the lack of an ideal filter, we must consider a distance between different channels in the frequency domain so that after filtering, the resulting signal is as free as possible of interference caused by other channels. This distance is called the frequency protection distance [9]. FDMA

    1-2-2- Multiple access method with time division TDMA

    In time sharing, time is divided into several parts and a number of these time parts are assigned to the received signal of each channel. To separate these signals, one should simply have a switch at their disposal to switch on the received signal at the right times and in this way separate the desired signal from all the received signals.

    It should be noted that in the FDMA technique there is no need for any coordination between different channels and they can send at their desired time. This issue does not exist in TDMA because all transmitters and receivers must have access to the same clock in order to know when to send or receive.

    The important point about FDMA and TDMA systems is that in these systems, different users operate on separate channels without interference. From the point of view of the signal space [10] in digital telecommunication, these multiple access techniques operate in such a way that different users are orthogonal to each other [11].

     

     

     
    Abstract

     

     

    The Investigation of Centralized and Decentralized Multiuser Detection Methods and Comparison of Their Performance

     

    In this thesis, the problem of information detection of the signals resulting from the superposition of the transmitted signals by multiple interfering users in a multiuser communication scenario (DS-CDMA systems) is investigated. Regarding the nature of this problem, it can be separated into two main categories: detection of the signals of all existing active users which is called "Centralized Multiuser Detection" and detection of the information of just one desired user which is called "Decentralized Multiuser Detection" in the literature. We have examined the common approaches for both. Specifically, for the centralized case, in which the information about the signature waveforms of all users is usually available, Maximum Likelihood (ML) detection and its implementation by sphere decoding have been discussed together with popular suboptimum approaches like decorrelating and MMSE detectors and V-BLAST detector. Likewise, for the decentralized case, two categories of detectors can be used: training sequence-based detectors and blind detectors.

  • Contents & References of Investigating and extracting centralized and decentralized multi-user detection algorithms and comparing their efficiency

    List:

    Chapter 1 Introduction. 1

    1-1- Introduction. 2

    1-2- Multiple access methods. 3

    1-2-1- FDMA frequency division multiple access method. 3

    1-2-2- TDMA time division multiple access method. 4

    1-2-3- random multiple access. 5

    1-2-4- Multiple access method with CDMA code division. 6

    1-2-5- Comparison of multiple access methods. 7

    1-3- Challenges in CDMA systems. 8

    1-3-1- the problem of distance-proximity. 8

    1-3-2-Multiple access interference 8

    1-4- Materials presented in this thesis. 8

    Chapter 2 overview of CDMA systems. 11

    2-1- Introduction. 11

    2-2- Transmitter and receiver structure in CDMA systems. 12

    2-3- Wide spectrum codes 13

    2-3-1- Maximum length pseudo-noise codes. 13

    2-3-2- Gold codes. 15

    2-3-3- Walsh codes. 15

    2-4- Simulation. 16

    Chapter 3 Focused Disclosure. 21

    3-1- Introduction: 21

    3-2- Signal model in DS-CDMA systems. 21

    3-3- traditional detector. 22

    3-4- Optimal receiver. 23

    3-5- spherical detection. 25

    3-6- Triangular high matrix detector. 30

    3-7- uncorrelated detectors and minimum mean square linear error. 33

    3-7-1- Uncorrelated detector 33

    3-7-2- Minimum mean square linear error detector. 35

    Page

     

    Title

     

     

     

     

    3-8- Non-linear detection and V-BLAST method. 37

    3-9- Simulation. 41

    3-9-1- traditional detector. 41

    3-9-2- optimal detection of ML and spherical detection. 42

    3-9-3- Comparison of centralized receivers. 44

    Chapter 4 Decentralized disclosure. 46

    4-1- Introduction. 47

    4-2- Revealing based on receiving educational courses. 47

    4-2-1- Adaptive detection of LMS. 50

    4-2-2- Adaptive detection of RLS. 51

    4-3- blind detection 52

    4-3-1- MOE detector. 52

    4-3-2- detector based on subspaces 55

    4-4- proposed fuzzy detector. 59

    4-5- Simulation. 66

    4-5-1- Comparison of methods based on receiving educational fields. 66

    4-5-2- comparison of blind detection methods 69

    4-5-3- proposed blind detection method 71

    Chapter 5 conclusions and suggestions. 73

    5-1- Conclusion. 74

    5-2- Suggestions. 75

    Sources and References

     

    Source:

     

    D. Tse and Pramod Viswanath, Fundamentals of Wireless Communication, Cambridge Univ. Press, 2005.

    S. Verd?, Multi-user detection, Cambridge University Press, 2003.

    S. Verd?, "Minimum Probability of Error for Asynchronous Gaussian Multiple Access Channel," IEEE Trans. on Inform. Theory, Vol. 32, No. 1, (January 1986), pp. 85-96.

    R. Lupas and S. Verd?, “Linear multiuser detectors for synchronous codedivision multiple-access channels,” IEEE Trans. Inf. Theory, vol. 35, No. 1, (January 1989), pp. 123-136.

    Hoing M. and Tsatsanis M. K., “Adaptive Techniques for Multiuser CDMA Receivers,” IEEE Signal Processing Magazine, Vol. 17, No. 3, (May 2000), pp. 49-61.

    Patra S. K. and Mulgrew B., “Fuzzy Techniques for Adaptive Nonlinear Equalization,” Signal Processing, Vol. 80, No. 6, (January 2000), pp. 985–1000.

    M. L. Honig, U. Madhow and S. Verd?, “Blind adaptive multiuser detection,” IEEE Trans. Inform. Theory, vol. 41, (July 1995), pp. 944–960.

    S. Boyd and L. Vandenberghe, Convex optimization, Cambridge University Press, 2004.

    X. Wang and H. V. Poor, “Blind Multiuser Detection: A Subspace Approach,” IEEE Trans. Inform. Theory, vol. 44, No. 2, (March 1998), pp. 677–690.

    S. Ch. Yong and Y. Y. Won, MIMO-OFDM wireless communication with MATLAB, IEEE Press, 2010.

    K. Zarifi and A. B. Gershman, “Asymptotic performance analysis of blind minimum output energy receivers for large DS-CDMA systems,” IEEE Trans. Signal Process., vol. 56, No. 2, (February 2008), pp. 650–663.

    P. H. Tan, "Multiuser detection in CDMA—Combinatorial optimization methods,"Tan, "Multiuser detection in CDMA—Combinatorial optimization methods," Licentiate's thesis, Chalmers Univ. of Technology, Gothenburg, Sweden, Nov. 2001.

    S. Verd?, "Multiuser detection," in Advances in Detection and Estimation. JAI Press, 1993.

    R. W. Heath, Jr., T. Strohmer, and A. J. Paulraj, “On quasi-orthogonal signatures for CDMA systems,” IEEE Trans. Inf. Theory, vol. 52, (March 2006), pp. 1217–1226.

    Patyra M. J., Grantner J. L. and K. Koster, “Digital fuzzy logic controller: Design and Implementation,” IEEE Transactions on Fuzzy Systems, Vol. 4, No. 4, (1996), pp. 439–459. Hykin S., Adaptive Filter Theory, 4th Ed., Prentice-Hall International, 2001. L. De Lathauwer and J. Castaing, “Tensor-based techniques for the blind separation of DS-CDMA signals,” Signal Process., Special Issue Tensor Signal Process., vol. 87, No. 2, (February 2007), pp. 322–336. P. M. Kroonenberg, Applied Multiway Data Analysis. : Wiley Series in Probability. Statist., 2008. J. G. Andrews, “Interference cancellation for cellular systems: A contemporary overview,” IEEE Wireless Commun. Mag., (April 2005), pp. 19-29.

    M. Hadef, S. Weiss and M. Rupp, “Adaptive Blind Multiuser DS-CDMA Downlink Equalizer,” Electronics Letters, (2005), Vol. 41, No. 21, pp. 1184-1185.

    Z. Xu, P. Liu, and X. Wang, “Blind multiuser detection: From MOE to subspace methods,” IEEE Trans. Signal Process., vol. 52, No. 2, (February 2004), pp. 510–524.

    E. Biglieri and M. Lops, “Multiuser Detection in Dynamic Environment-Part 1: User Identification and Data Detection,” IEEE Trans. on Information Theory, vol. 53, No. 9, (2007), pp. 3158-3170.

    Hoing M. and Tsatsanis M. K., “Adaptive Techniques for Multiuser CDMA Receivers,” IEEE Signal Processing Magazine, Vol. 17, No. 3, (May 2000), pp. 49-61.

    Ghotbi M. and Soleymani M. R., "MMSE-Based Adaptive Detection of DS-CDMA Signals", IEEE CCECE Conference, (May 2005), pp. 81-84.

    Woodward G. and Vucetic B. S., "Adaptive Detection for DS-CDMA," Proceedings of the IEEE, Vol. 86, No. 7, (July 1998), pp. 1413-1434.

    Rapajic P.B. and Vucetic B.S., "Adaptive Receiver Structures for Asynchronous CDMA Systems," IEEE Journal on Selected Areas of Communications, Vol. 12, No.4, (May 1994), pp. 685-697.

    Moshavi S., “Multiuser Detection for DS-CDMA Communications,” IEEE Communication Magazine, Vol. 34, No. 10, (October 1996), pp. 124-136.

    Poor H. V., Verdu S., “Single-user Detectors for Multiuser Channels,” IEEE Trans. on Communications, Vol. 36, No. 1, (January 1988), pp. 50-60.

    Peterson Roger L., Ziemer Rodger E., Borth David E., "Introduction to spread spectrum communications", PEARSON Education, 2005.

    Dinan E.H. and Jabbari B., “Spreading Codes for Direct Sequence CDMA and Wideband CDMA Cellular Networks,” IEEE Communication Magazine, Vol. 36, No. 9, (September 1998), pp.48 - 54.

    Lee W.C.Y., "Overview of Cellular CDMA," IEEE Transactions on Vehicular Technology, Vol. 40, No. 2, (May 1991), pp. 291-302.

    Hanzo L., Yang L-L., Kuan E-L., Yen K., Single and Multi-Carrier DS-CDMA: Multi-User Detection, Space-Time Spreading, Synchronization, Networking and Standards, John Wiley and Sons, 2003.

    Gan W. S., “Designing a Fuzzy Step Size LMS Algorithm,” IEE Proceedings -Vision, Image and Signal Processing, Vol. 144, No. 5, (October 1997), pp. 261–266.

    Zadeh L.A., "Fuzzy sets", Information and Control, Vol. 8, No. 3, (June 1965), pp. 338-353.

    D. Seethaler and H. Bolskei, "Performance and Complexity Analysis of Sphere Decoding" IEEE Trans. Inform. Theory, Vol. 56, No. 3, (March 2010), pp. 456-477.

    S. A. Hosseini, O. Javidbakht, P. Pad and F. Marvasti, “A Review on Synchronous CDMA Systems; Optimum overloaded codes, channel capacity, and power control" EURASIP Journal on Wireless Communication and Networking, Vol. 62, (2011), pp. 234-245.

    T.

Investigating and extracting centralized and decentralized multi-user detection algorithms and comparing their efficiency
How To Access The File
Related Contents:
Number of pages: 131 Category: Computer Engineering

Thesis for obtaining a master's degree in the field: computer, software, abstract. In a sensor network, which is a pervasive distributed system, communication synchronization is one of the discussed cases. One of the main tasks of synchronizing processes is mutual exclusivity. The new algorithms provided are more fair compared to the old algorithms. In this thesis, we present a ...

Number of pages: 142 Category: IT Information Technology Engineering

Master's Thesis in Information Technology Engineering, Computer Networks, Abstract Location and synchronization are key elements in many underwater communication applications, which, despite being highly interdependent, usually operate separately from each other. But since the synchronization services are the prerequisite of the positioning algorithms and the information about ...

Number of pages: 146 Category: Telecommunication Engineering

Master's thesis in the field of telecommunication engineering - abstract system of investigating the methods of incoherent detection of broadband signals with the emergence and expansion of telecommunication systems with very narrow pulse width, very wide bandwidth, the limitation of bandwidth and speed of existing electronic components, the use of many previously known ...

Number of pages: 104 Category: Computer Engineering

Master's thesis in the field of computer engineering (artificial intelligence) abstract of various image processing techniques are widely used in the field of dentistry. Among these applications, we can mention the identification based on dental images, the detection of dental caries, as well as the identification and examination of dental lesions, which mainly occur around the ...

Number of pages: 120 Category: Electronic Engineering

Master's thesis in the field of electrical engineering-communication system for removing interference in the passive radar reference channel based on digital TV broadcast signal by terrestrial transmitters with a reproduction approach. In this thesis, a digital receiver for signal processing in a passive radar reference receiver based on orthogonal frequency division modulation ...

Number of pages: 120 Category: Electrical Engineering

Master's Thesis in the field of Electrical Engineering-Communications System Abstract of interference removal in passive radar reference channel based on digital TV broadcast signal by terrestrial transmitters with a reproduction approach. In this thesis, a digital receiver for signal processing in a passive radar reference receiver based on orthogonal frequency division ...

Number of pages: 100 Category: Computer Engineering

Dissertation for Master's Degree in Artificial Intelligence Abstract In this thesis, we intend to perform classification on brain signals by presenting a suitable feature. For this purpose, first the noise of the recording device is removed from the brain signals, then the features are extracted from these signals using Walsh transform and entropy. After feature extraction, ...

Number of pages: 95 Category: Electronic Engineering

Master's Thesis in Telecommunication Electrical Engineering- LFSR-based scrambler parameter blind detection system in digital data In digital telecommunication systems, linear scramblers are used both for simple encryption and for breaking a large sequence of identical bits. The bit sequence issue, i.e. a large number of 0's and 1's in a row, usually leads to synchronization ...

Number of pages: 128 Category: Electrical Engineering

Master's thesis in the field of electrical engineering, system communication Abstract: Investigating routing algorithms in radiological networks and presenting a method to improve the output of the radiological technology network was first expressed by Dr. Mitola in 1999 and in recent years has created an emerging evolution in the field of radio communication that can provide ...

Number of pages: 94 Category: Electrical Engineering

Master's Thesis in Telecommunication Electrical Engineering- LFSR-based scrambler parameter blind detection system in digital data by Zahra Zakeri In digital telecommunication systems, linear scramblers are used both for simple encryption and for breaking a large sequence of identical bits. The bit sequence issue, i.e. a large number of 0's and 1's in a row, usually leads to ...