The Experts below are selected from a list of 100755 Experts worldwide ranked by ideXlab platform
Yuanan Liu - One of the best experts on this subject based on the ideXlab platform.
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ICC - Full Diversity Spreading code for Downlink Space-Time-Frequency Spreading CDMA
2008 IEEE International Conference on Communications, 2008Co-Authors: Siyang Liu, Yachen Wang, Feifei Wang, Ranran Zhang, Yuanan LiuAbstract:Recently proposed downlink space-time-frequency spreading CDMA (STFS-CDMA) is investigated in this paper. By analyzing, a spreading code design criterion of it is derived. From the criterion, we can see that the original two classes of spreading code adopted in STFS-CDMA, Walsh-Hadamard code (WHC) and double-orthogonal code (DOC), both can not always achieve the full space and frequency diversity. Then, a novel spreading code, zero padded rotary FFT code (ZPRFC), is proposed. Compared with WHC coded STFS-CDMA (WHC-STFS-CDMA) and DOC coded STFS-CDMA (DOC-STFS-CDMA), the novel ZPRFC coded STFS-CDMA (ZPRFC-STFS-CDMA) can obtain the full space and frequency diversity at the cost of the reduction of the number of supporting users.
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Spreading Code Design for Downlink Space-Time-Frequency Spreading CDMA
IEEE Transactions on Vehicular Technology, 2008Co-Authors: Siyang Liu, Yuanan Liu, Zhendong Luo, Jinchun GaoAbstract:In this paper, we analyze the recently proposed downlink space-time-frequency spreading code-division multiple-access (STFS-CDMA) scheme. A spreading code design criterion is first derived for STFS-CDMA. From the spreading code design criterion, we can see that the two original spreading codes adopted in STFS-CDMA, i.e., the Walsh-Hadamard code (WHC) and the double-orthogonal code (DOC), both cannot achieve full space and frequency diversity, no matter how many users exist in the system. Then, a novel spreading code, i.e., permutated DOC (PDOC), is proposed. PDOC-coded STFS-CDMA (PDOC-STFS-CDMA) can obtain full space and frequency diversity when the number of users in the system is only one, but it cannot obtain full space and frequency diversity when the number of users is larger than one. To mitigate this problem, a zero-padded rotary fast Fourier transform code (ZPRFC) is proposed. Compared with WHC-coded STFS-CDMA (WHC-STFS-CDMA), DOC-coded STFS-CDMA (DOC-STFS-CDMA), and PDOC-STFS-CDMA, ZPRFC-coded STFS-CDMA (ZPRFC-STFS-CDMA) cannot only always obtain full space and frequency diversity but can also result in a low-complexity receiver at the cost of the reduction of the number of supporting users. Finally, the simulation results are given to compare with the performances of WHC-STFS-CDMA, DOC-STFS- CDMA, PDOC-STFS-CDMA, and ZPRFC-STFS-CDMA.
Siyang Liu - One of the best experts on this subject based on the ideXlab platform.
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ICC - Full Diversity Spreading code for Downlink Space-Time-Frequency Spreading CDMA
2008 IEEE International Conference on Communications, 2008Co-Authors: Siyang Liu, Yachen Wang, Feifei Wang, Ranran Zhang, Yuanan LiuAbstract:Recently proposed downlink space-time-frequency spreading CDMA (STFS-CDMA) is investigated in this paper. By analyzing, a spreading code design criterion of it is derived. From the criterion, we can see that the original two classes of spreading code adopted in STFS-CDMA, Walsh-Hadamard code (WHC) and double-orthogonal code (DOC), both can not always achieve the full space and frequency diversity. Then, a novel spreading code, zero padded rotary FFT code (ZPRFC), is proposed. Compared with WHC coded STFS-CDMA (WHC-STFS-CDMA) and DOC coded STFS-CDMA (DOC-STFS-CDMA), the novel ZPRFC coded STFS-CDMA (ZPRFC-STFS-CDMA) can obtain the full space and frequency diversity at the cost of the reduction of the number of supporting users.
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Spreading Code Design for Downlink Space-Time-Frequency Spreading CDMA
IEEE Transactions on Vehicular Technology, 2008Co-Authors: Siyang Liu, Yuanan Liu, Zhendong Luo, Jinchun GaoAbstract:In this paper, we analyze the recently proposed downlink space-time-frequency spreading code-division multiple-access (STFS-CDMA) scheme. A spreading code design criterion is first derived for STFS-CDMA. From the spreading code design criterion, we can see that the two original spreading codes adopted in STFS-CDMA, i.e., the Walsh-Hadamard code (WHC) and the double-orthogonal code (DOC), both cannot achieve full space and frequency diversity, no matter how many users exist in the system. Then, a novel spreading code, i.e., permutated DOC (PDOC), is proposed. PDOC-coded STFS-CDMA (PDOC-STFS-CDMA) can obtain full space and frequency diversity when the number of users in the system is only one, but it cannot obtain full space and frequency diversity when the number of users is larger than one. To mitigate this problem, a zero-padded rotary fast Fourier transform code (ZPRFC) is proposed. Compared with WHC-coded STFS-CDMA (WHC-STFS-CDMA), DOC-coded STFS-CDMA (DOC-STFS-CDMA), and PDOC-STFS-CDMA, ZPRFC-coded STFS-CDMA (ZPRFC-STFS-CDMA) cannot only always obtain full space and frequency diversity but can also result in a low-complexity receiver at the cost of the reduction of the number of supporting users. Finally, the simulation results are given to compare with the performances of WHC-STFS-CDMA, DOC-STFS- CDMA, PDOC-STFS-CDMA, and ZPRFC-STFS-CDMA.
Jinchun Gao - One of the best experts on this subject based on the ideXlab platform.
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Spreading Code Design for Downlink Space-Time-Frequency Spreading CDMA
IEEE Transactions on Vehicular Technology, 2008Co-Authors: Siyang Liu, Yuanan Liu, Zhendong Luo, Jinchun GaoAbstract:In this paper, we analyze the recently proposed downlink space-time-frequency spreading code-division multiple-access (STFS-CDMA) scheme. A spreading code design criterion is first derived for STFS-CDMA. From the spreading code design criterion, we can see that the two original spreading codes adopted in STFS-CDMA, i.e., the Walsh-Hadamard code (WHC) and the double-orthogonal code (DOC), both cannot achieve full space and frequency diversity, no matter how many users exist in the system. Then, a novel spreading code, i.e., permutated DOC (PDOC), is proposed. PDOC-coded STFS-CDMA (PDOC-STFS-CDMA) can obtain full space and frequency diversity when the number of users in the system is only one, but it cannot obtain full space and frequency diversity when the number of users is larger than one. To mitigate this problem, a zero-padded rotary fast Fourier transform code (ZPRFC) is proposed. Compared with WHC-coded STFS-CDMA (WHC-STFS-CDMA), DOC-coded STFS-CDMA (DOC-STFS-CDMA), and PDOC-STFS-CDMA, ZPRFC-coded STFS-CDMA (ZPRFC-STFS-CDMA) cannot only always obtain full space and frequency diversity but can also result in a low-complexity receiver at the cost of the reduction of the number of supporting users. Finally, the simulation results are given to compare with the performances of WHC-STFS-CDMA, DOC-STFS- CDMA, PDOC-STFS-CDMA, and ZPRFC-STFS-CDMA.
Ramjee Prasad - One of the best experts on this subject based on the ideXlab platform.
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wideband CDMA for third generation mobile communications
1998Co-Authors: T. Ojanpera, Ramjee PrasadAbstract:Basic principles of DS-CDMA applications radio operating environments and their impact into system design system design aspects a novel wieband CDMA radio interface typical wideband CDMA radio interfaces performance analysis time division duplex (TDD) DS-CDMA hierarchical cell structures implementation aspects radio nerwork planning and deployment network aspects comparison to TDMA and other 3rd generation radio interface proposals future developments.
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overview of multicarrier CDMA
IEEE Communications Magazine, 1997Co-Authors: Shinsuke Hara, Ramjee PrasadAbstract:The authors present an overview of new multiple access schemes based on a combination of code division and multicarrier techniques, such as multicarrier code-division multiple access (MC-CDMA), multicarrier direct sequence CDMA (multicarrier DS-CDMA), and multitone CDMA (MT-CDMA).
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CDMA for wireless personal communications
1996Co-Authors: Ramjee PrasadAbstract:From the Publisher: Code Division Multiple Access (CDMA) is a hot topic. Until now, it has only been used in satellite and military systems, but engineers are starting to recognize certain advantages it has over FDMA and TDMA for use in cellular radio. This book provides the first comprehensive analysis of the theory and practical applications of CDMA. Authored by a recognized expert in the field, it fills a gap in current literature by explaining the use of CDMA in different environments, presenting CDMA as a multiple access protocol for wireless indoor, outdoor, and land mobile satellite communication systems. This is cutting-edge information for all those involved in the future of wireless personal communications. It enables engineers, researchers and students to: ? Compare wired (cable) and wireless network systems ? Understand multiple access protocols ? Learn hybrid CDMA ? Apply CDMA to various mobile systems ? Investigate multiple access schemes for future wireless communication systems You'll gain a complete overview of CDMA, as well as useful solutions to the general problems of wireless communications as they relate to CDMA protocol, and recommended techniques to enhance the performance of a CDMA-based wireless personal communication system. Because the author recognizes that CDMA will have to be implemented in phases, he also addresses the practicalities of the coexistence of CDMA and TDMA. Complete with 180 illustrations, 400 equations, practical examples, and appendices.
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ber comparison of ds CDMA and mc CDMAc for frequency selective fading channels
Signal Processing in Telecommunications, 1996Co-Authors: Shinsuke Hara, Taihin Lee, Ramjee PrasadAbstract:This paper presents the advantages and disadvantages of DS-CDMA (Direct Sequence-Code Division Multiple Access) and MC-CDMA (Multi-Carrier-Code Division Multiple Access) systems in synchronous down-link mobile radio communication channels. Furthermore, the bit error rate (BER) performance is analyzed in frequency selective slow Rayleigh fading channels. We theoretically derive the BER lower bound for MC-CDMA system, and propose a simple multi-user detection method. In the BER analysis, we use the same multipath delay profiles for both DS-CDMA and MC-CDMA systems, and discuss the performance theoretically and by computer simulation. Finally, we theoretically prove that the time domain DS-CDMA Rake receiver is equivalent to the frequency domain MC-CDMA Rake receiver for the case of one user.
Ranran Zhang - One of the best experts on this subject based on the ideXlab platform.
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ICC - Full Diversity Spreading code for Downlink Space-Time-Frequency Spreading CDMA
2008 IEEE International Conference on Communications, 2008Co-Authors: Siyang Liu, Yachen Wang, Feifei Wang, Ranran Zhang, Yuanan LiuAbstract:Recently proposed downlink space-time-frequency spreading CDMA (STFS-CDMA) is investigated in this paper. By analyzing, a spreading code design criterion of it is derived. From the criterion, we can see that the original two classes of spreading code adopted in STFS-CDMA, Walsh-Hadamard code (WHC) and double-orthogonal code (DOC), both can not always achieve the full space and frequency diversity. Then, a novel spreading code, zero padded rotary FFT code (ZPRFC), is proposed. Compared with WHC coded STFS-CDMA (WHC-STFS-CDMA) and DOC coded STFS-CDMA (DOC-STFS-CDMA), the novel ZPRFC coded STFS-CDMA (ZPRFC-STFS-CDMA) can obtain the full space and frequency diversity at the cost of the reduction of the number of supporting users.
