Download or read book Performance Analysis of Parallel Interference Cancellation for CDMA Systems written by Yidai Li and published by . This book was released on 2002 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Performance Analysis of Integrated Interference Cancellation and Decoding for CDMA Systems written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: HKUST Call Number: Thesis ELEC 2000 Shurk.

Download or read book Performance Analysis of Linear Multistage Interference Cancellation in Long code CDMA Systems written by Chien-Hwa Hwang and published by . This book was released on 2003 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Performance Analysis of MC CDMA and CI MC CDMA Using Interference Cancellation Techniques written by Anshul Sharma and published by . This book was released on 2008 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt: Efficient use of the spectrum is an essential problem in creating any multi-user cellular mobile system. The bandwidth requirements of the future 4G systems far exceed what the existing traditional setup can provide. A more creative utilization of the available bandwidth is more important now than ever before. Improved receiver design that utilizes the frequency and code diversity of the MC-CDMA schemes is one way of increasing the number of users supported at very high bitrates. We discuss the MC-CDMA system operating over a frequency selective, slowly fading channel. We study in detail multiuser Parallel Interference Cancellation detectors employing the MRC and MMSE detectors. Various configurations of the PIC are studied and simulated to evaluate and understand the comparative advantages and disadvantages. In this thesis we offer a review of the literature available on MC-CDMA and CI/MC-CDMA systems. We study the performance of the MRC-PIC-MMSE system both semi-analytically and by computer simulations. By means of computer simulations, we also compare the advantages of using the Carrier Interferometry codes over the Walsh Hadammard codes under various system configurations.

Download or read book Improved Cdma Performance Using Parallel Interference Cancellation written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-08 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report considers a general parallel interference cancellation scheme that significantly reduces the degradation effect of user interference but with a lesser implementation complexity than the maximum-likelihood technique. The scheme operates on the fact that parallel processing simultaneously removes from each user the interference produced by the remaining users accessing the channel in an amount proportional to their reliability. The parallel processing can be done in multiple stages. The proposed scheme uses tentative decision devices with different optimum thresholds at the multiple stages to produce the most reliably received data for generation and cancellation of user interference. The 1-stage interference cancellation is analyzed for three types of tentative decision devices, namely, hard, null zone, and soft decision, and two types of user power distribution, namely, equal and unequal powers. Simulation results are given for a multitude of different situations, in particular, those cases for which the analysis is too complex. Simon, Marvin and Divsalar, Dariush Jet Propulsion Laboratory...

Download or read book Performance Evaluation of Combined Code space Division Multiple Access with Enhanced Parallel Interference Cancellation written by Nidhal A. S. Odeh and published by . This book was released on 2007 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt: To meet the ever growing need for wireless networks, several methods were adopted to increase the system capacity of wireless communication systems, such as Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Code Division Multiple Access (CDMA), Space Division Multiple Access (SDMA) and Orthogonal Frequency Division Multiplexing (OFDM). In this thesis, Combined Code Division Multiple Access (CDMA) and Space Division Multiple Access (SDMA) system have been investigated for capacity improvement. The analysis considered here is to evaluated the performance of the combined Code-Space Dividion Multiple Access (C-SDMA) system. A single cell composed with one base station (BS) and N class of users is considered. The heterogenous enviroment each user class is supported by one of the different media with specific data rates and minimum required quality of service. In this thesis, the synchronous uplink channel transmission in investigated in order to detect the received signal (bits) in a combined C-SDMA system with perfect power control, with and without interference cancellation. Parallel interference cancellation (PIC) as a suboptimal multiuser detection (MUD) was employed after the matched filter (MF) receiver. The performance of the C-SDMA systems was evaluated in terms of bit error rate (BER) and user capacity, considering all the transmitted bits from other interferer users. Additionally, some asymptotic behaviour of the combined system was analyzed at high and low signal-to-noise and interference ratio (SNIR) for the desired user. Comparison between the pure CDMA and combined C-SDMA systems is done in terms of system performance with and without interference cancellation. By using limited number of available spreading codes, a novel code assignment algorithm is proposed to maintain the maximum orthogonality among users. These codes are stored in a central pool (BS) and maintained as follows. When a new user requests for a channel , the BS first checks the available signatures in terms of codes and Angle of Arrival (AoA); it then assigns the user with an already used code (used by other users) if they are spatially orthogonal to each other, otherwise an available new code will be assigned. If all codes are already utilized then the user will be blocked. Finally, the probability of blocking was evaluated in terms of various numbers of available codes. Matlab was used as the simulation software throughout this thesis. The results obtained showed that the combined C-SDMA system improve the performance by about 4 dB gain over the pure CDMA system at BER of 10-1. On the other hand the system gains 5 dB in the combined C-SDMA system in PIC receiver over the receiver without PIC at BER 10-4. Hence, it is apparent that the combined C-SDMA system with PIC is able to accomodate more users than the other systems. Finally, the code assignment algorithm is able to further enhance the system capacity by utilizing the same resources compared to the fixed code assignment strategy. In this case, the probability of blocking can be decreased substantially by adding few numbers of additional spreading codes in the system.

Download or read book Parallel Interference Cancellation Multiuser Detectors for DS CDMA Communication Systems written by Feng Liu and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A nonlinear sub-optimal multiuser detector in the form of parallel interference cancellation (PIC) has been studied. The main objective of this thesis is to develop an analytical model for PIC performance analysis and propose new near-optimum approach. Since the exact performance analysis of PIC is difficult to derive due to its nonlinear decision function, previous work tends to adopt computer simulation method or evaluate through Gaussian approximation (GA) method. For PIC detector, the GA method may not apply since there may exist a dominate interference signal. In addition, the central limit theorem is not applicable to model the residual MAI in the case of PIC due to its own structural property. We develop an analytical model to derive the exact BER performance in the case of two users, and extend the method to approximate cases when moderate-to-high SINR can be encountered. We propose a gradient adaptive parallel interference cancellation detector and investigate its performance. The presented PIC detector is equipped with a set of adaptive weights which are adjusted through a new proposed gradient adaptive step size-LMS (GASS-LMS) algorithm to reduce the cost of wrong interference estimation as existed in the conventional PIC. The initial state is deliberately set based on the function of probability of error to reflect the reliability of the tentative decision from the previous stage. While the most previous work on MUD are restricted to cases where there is no intersymbol interference (ISI), we consider the problem of joint detection of MAI and ISI, which is crucial to enhance the performance of the third and future generation systems with high data rate applications. Simulation results are provided to show that our low complexity joint detector can perform very well, yielding the bit error rate (BER) close to the non-ISI single-user error rate.

Download or read book Parallel Interference Cancellation Multiuser Detection written by Donald Richard Brown and published by . This book was released on 2000 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Trickle based Interference Cancellation Schemes for CDMA Systems written by Pooyan Haghighat and published by . This book was released on 2008 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, we introduce a novel approach to interference cancellation for code division multiple access uplink transmission. Several models combining principles of serial and parallel interference cancellation are discussed. The proposed scheme is derived from the analysis of these hybrid models and applies a user configuration algorithm (termed "trickle") in order to provide an improved bit-error-rate performance. The algorithm utilizes an adaptive matrix to compute the required configuration to be used for the subsequent interference cancellation stage. Bit-streaming, pipelined multiuser detection is employed and channel estimates are obtained using sample pilot data known at the receiver. We demonstrate that significant performance improvements can by achieved over various hybrid schemes. A reduced-complexity version of the trickle algorithm is also introduced where the processing delay is greatly reduced while maintaining similar performance. We present several numerical examples through which we demonstrate the efficacy of the proposed algorithms relative to existing interference cancellation algorithms.

Download or read book Conference Proceedings written by and published by . This book was released on 2004 with total page 738 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book CDMA Performance Using Parallel Interference Cancellation Over the Rayleigh Fading Channel written by and published by . This book was released on 2003 with total page 47 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Multiplexing written by Somayeh Mohammady and published by BoD – Books on Demand. This book was released on 2019-09-04 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mobile communication has been a critical part of everyday life for the last 30 years. As the demand for wireless communications and higher data rates on these links continues its rapid growth, engineers, scientists, and researchers are required to advance the hardware and software needed to deliver systems for 5G, Massive multiple-input, multiple-output (MIMO), and optical backhaul networks. Now, more than ever before, the fundamental concept of multiplexing is at play. This book is a unique reference for understanding the concept of multiplexing. It provides comprehensive coverage of the practical applications of multiplexing to help the reader better understand its use in these systems. It is a great resource, especially for engineers working on digital signal processing, radio frequency (RF), antenna design, beamforming, and network designs. The book contains chapters on the following topics: • History of multiplexing and how it applies to current technologies; • Different types and applications of multiplexing; • Multiplexing techniques in wireless networks; • Multiple-Input, Multiple-Output Orthogonal Frequency-Division Multiplexing (MIMO-OFD); • Direct-Sequence Optical-Code Division Multiple-Access (DS-OCDMA); • Optically multiplexed systems

Download or read book Proceedings of the International Conference on Emerging Technologies in Intelligent System and Control written by and published by Allied Publishers. This book was released on 2005 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: Contributed articles presented in the seminar held during Jan. 5-7, 2005, at Kumaraguru College of Technology, Coimbatore.

Download or read book IETE Journal of Research written by and published by . This book was released on 2005 with total page 538 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Improved Subtractive Interference Cancellation for DS CDMA written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Third generation wireless systems are being brought into operation rapidly. Multiuser detection is a key technology that can substantially increase the system capacity. Subtractive interference cancellation is a major category of multiuser detection. Due to their lower complexity, subtractive interference cancellation approaches are attractive for the practical implementation of multiuser detection. This thesis begins with a brief study of several multiuser detection techniques followed by an investigation of subtractive interference cancellation techniques. Two basic schemes, successive interference cancellation (SIC) and parallel interference cancellation (PIC) are discussed in detail and other schemes based on these two, a hybrid and a groupwise scheme, are also introduced. Both SIC and PIC have disadvantages. Consequently, a multistage groupwise weighted interference cancellation (MGWIC) scheme that is flexible in practical implementation and has good performance is proposed and analyzed. The analysis and simulation for a simplified case are presented. The implementation and performance under other conditions are also discussed.

Download or read book Proceedings of the Eleventh National Conference on Communications written by and published by Allied Publishers. This book was released on 2005 with total page 720 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Multiuser Detection of DS CDMA Signals Using Parallel Interference Cancellation in Wireless Communications written by Mohsen Ghotbi and published by . This book was released on 2001 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In a limited network resource, techniques are needed to share the channel among different users as efficiently and as fairly as possible. Among multiple access techniques; Code Division Multiple Access (CDMA) has the exclusive advantage of allowing all active users share the same channel concurrently. When CDMA technique is used, Multi User Detection (MUD) is needed to reject or reduce the Multiple Access Interference (MAI) affecting each active user. In this thesis, it is shown that multiuser detection using Parallel Interference Cancellation (PIC) technique provides a good compromise among the complexity, latency, and performance. This technique is suitable for Digital Video Broadcasting-Return Channel via Satellite (DVB-RSC) as well as Base Station (BS) in cellular communication systems. We offer a new scheme that is a combination of soft and hard PIC detectors whose performance is superior to that of the other famous sub-optimal detectors. For most MUD schemes, a perfect knowledge of users' parameters is required. In this thesis, we apply a very simple method to estimate the parameters. PIC detectors are usually studied in equal-power case, i.e., a perfect power control scheme is assumed. We study PIC detector in near-far condition as well, where users arrive at receiver with different power levels. It is shown that our proposed scheme has some advantages over other schemes. First, it is much less complex than optimal and linear detectors. Second, it is much faster than sequential detector. Third, it has better performance than that of linear detectors.