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Papers by Branimir Vojcic

Abstract–In this paper, we study the uplink of a cellular network where reservation random access... more Abstract–In this paper, we study the uplink of a cellular network where reservation random access schemes such as reservation slotted ALOHA and reservation slotted nonpersistent ISMA are used for multiple access. When channel state information is not available to users when they contend for channel access, we find that capture effect inherent in wireless communications can exploit the channel variations and reserve users with favorable channels for data transmission. We investigate two channel models where in the first model, channel variations come from time-varying Nakagami-m fading and in the second model, mobile users have both time-varying fading and path loss. Index Terms–Random access, multiuser diversity, Nakagami-m fading I.

The SOPRANO project involves a novel adaptive and scalable wireless network architecture utilizin... more The SOPRANO project involves a novel adaptive and scalable wireless network architecture utilizing a mixture of cellular and multihop packet radio system topologies with potential to support a variety of applications including high data rate Internet and multimedia tra#c at a reasonable degree of implementation complexity. This article discusses the potential benefits of this structure and addresses several relevant issues necessary to support such a network. More specifically, it focuses on connection establishment and self-organization, investigates the formulation of an optimum transmission strategy, and examines some of the techniques by which we can augment the capacity or enhance the system performance in this multihop network. We also present capacity bounds which illustrate how these techniques help in trading o# conserved power for a multiple fold capacity advantage.

Preface. New Mobile Telephony in the Organisational Communication O. Galibert, et al. System Over... more Preface. New Mobile Telephony in the Organisational Communication O. Galibert, et al. System Overload and System Utilization - Myths and Realities D. McRae, et al. Experimental GSM Test Bed for Adaptive Array Antenna System G. Bucci, et al. High Speed Optical Data Link for Smart Antenna Mobile Radio System C. Savazzi. Spectrally Efficient Turbo Codes with Full Antenna Diversity H.-J. Su, E Geraniotis. A Novel DAB Technique Using Code Combining, Packet Combining, and Iterative Decoding (Turbo Code) B.K. Yi, et al. Multiple Access Using Periodic Clock Changes Through Slow Fading Multipath Channel A. Hayar, et al. On the Impact of Signal-Level-Based Power Control on Terminal Battery Duration M. Chiani, et al. Generalized Quasi-Walsh PN Sequences and Their Applications in Robust CDMA Communications Systems C. Giardina, A.N. Rudrapatna. Rate Processor Sharing: A Robust Technique for Scheduling Data Transmissions in CDMA Wireless Networks K. Kumaran, P. Whiting. The Initial Synchronisatio...

Preface. New Mobile Telephony in the Organisational Communication O. Galibert, et al. System Over... more Preface. New Mobile Telephony in the Organisational Communication O. Galibert, et al. System Overload and System Utilization - Myths and Realities D. McRae, et al. Experimental GSM Test Bed for Adaptive Array Antenna System G. Bucci, et al. High Speed Optical Data Link for Smart Antenna Mobile Radio System C. Savazzi. Spectrally Efficient Turbo Codes with Full Antenna Diversity H.-J. Su, E Geraniotis. A Novel DAB Technique Using Code Combining, Packet Combining, and Iterative Decoding (Turbo Code) B.K. Yi, et al. Multiple Access Using Periodic Clock Changes Through Slow Fading Multipath Channel A. Hayar, et al. On the Impact of Signal-Level-Based Power Control on Terminal Battery Duration M. Chiani, et al. Generalized Quasi-Walsh PN Sequences and Their Applications in Robust CDMA Communications Systems C. Giardina, A.N. Rudrapatna. Rate Processor Sharing: A Robust Technique for Scheduling Data Transmissions in CDMA Wireless Networks K. Kumaran, P. Whiting. The Initial Synchronisation Procedure in UMTS W-CDMA S. Kourtis. Iterative MMSE Multiuser Detection for Coded CDMA Channels with Multisensor Transmitter and Receiver Arrays J. Thomas, E. Geraniotis. Trading-off Capture Against Packet Separation for Throughput and Energy Efficiency in Random Access Systems W. Luo, A. Ephremides. The Concept of PARPS - Packet and Resource Plan Scheduling M. Eriksson, H. Saterberg. A Distributed Channel Allocation Method for Self-Organising Base Stations in a Wireless ATM Unlicensed System G.F. Marias, L. Merakos. Resource Allocation for Integrated Voice/WWW Traffic in UMTS/TDD Systems C. Mihailescu, et al. An Extended Error Control Technique for Wireless ATM Channel Z. Ilic, et al. Universal Platform for High-Speed Wireless OFDM Link Evaluation K.Verdijck. Seamless Multimedia Service for Third Generation Mobile Radio Networks M. Ferracioli, R. Verdone. Cell Assignability on Random Paths in CDMA Networks A. Leu, B. Jabbari. Key Issues in Handover Design and Multi-Layer Cellular System Design M. Lohi, et al. Configuration Data Verification and Design Techniques for Mobile Network Architecture Nodes D. D'Aurelio, et al. Investigation of Alternative ARQ Schemes for a Wireless ATM Network Architecture Nodes D. D'Aurelio, et al. Investigation of Alternative ARQ Schemes for a Wireless ATM Network D. Skyrianoglou, L. Merakos. Fair Sharing of MAC under TCP in Wireless Ad-hoc Networks K. Tang, M. Gerla. Fair Queueing Scheduler for IEEE 802.11 Based Wireless Multimedia Networks R.S. Ranasinghe, et al. Performance Analysis of a Cellular Slotted CDMA System with Imperfect Power Control over a Rayleigh Fading Channel J.M. Romero Jerez, et al. Efficiency Comparison Between CDMA and PRMA-HS in Low Earth Orbit Mobile Satellite Systems A. Abrardo, et al. Multiple Access Interference in Multi-beam CDMA-based LEO Satellite Systems H. Fu, et al. Capacity Considerations for Wireless MIMO Channels F. Boixadera Espax, J.J. Boutros. Determination of Critical Transmission Range in Ad-Hoc Networks M. Sanchez, et al. An Adaptive QoS Representation and Resource Allocation Scheme for Multimedia and Wireless ATM Networks Using Genetic Algorithms M.R. Sherif, et al.

Wirel Pers Commun, 1996

ABSTRACT

Ieee Globecom 2007 Ieee Global Telecommunications Conference, Nov 1, 2007

ABSTRACT Based on an analysis on the recursive computation of the iterative maximum a posteriori ... more ABSTRACT Based on an analysis on the recursive computation of the iterative maximum a posteriori (MAP) algorithm for turbo decoding, this paper considers a modified MAP scheme with reduced block lengths for symbols with unreliable detection after some initial iterations. Applying symbol selection based on cross-entropy measurement for parallel concatenated convolutional codes, we develop partial, windowed iterations for selected symbols. By omitting computations for symbols with reliable detection results, this approach significantly reduces complexity but well maintains the performance by complete iterations.

Ieee Transactions on Communications, Nov 1, 2009

Near-capacity performance of turbo codes is generally achieved with a large number of decoding it... more Near-capacity performance of turbo codes is generally achieved with a large number of decoding iterations. Various iteration stopping rules introduced in the literature often induce performance loss. This paper proposes a novel partial decoding iteration scheme using a bit-level convergence test. We first establish decoding optimality of windowed partial iteration for non-converged bits given that convergence has been achieved on window boundaries. We next present two criteria for testing bit convergence based on cross-entropy, and propose a windowed partial iteration algorithm. The overall complexity and memory requirements of the new algorithm are evaluated and compared with known algorithms. Simulations reveal that the proposed scheme suffers essentially no performance loss compared to full iterations, while reducing the decoding complexity. We also briefly discuss possible extensions of the proposed scheme to general iterative receivers.

Acoustics Speech and Signal Processing 1988 Icassp 88 1988 International Conference on, 2009

ABSTRACT This paper proposes a bit-selective iterative processing scheme for turbo equalization. ... more ABSTRACT This paper proposes a bit-selective iterative processing scheme for turbo equalization. We consider convolutionally coded and turbo coded transmissions over inter-symbol interference (ISI) channels. The receiver starts with conventional iterative channel equalization and decoding. After each iteration, bit convergence status is measured via cross-entropy. Short windows are then applied around unconverged bits and the subsequent detection/decoding iterates only within the windows. The rapid decrease in selected bits after each such iteration reduces computational complexity significantly, but performance is well maintained by utilizing the Markov property in the trellis detection/decoding.

Ieee Transactions on Wireless Communications, Jun 1, 2009

Multicarrier techniques based on affine Fourier transform (AFT) have been recently proposed for t... more Multicarrier techniques based on affine Fourier transform (AFT) have been recently proposed for transmission in the wireless channels. The AFT represents a generalization of the Fourier and fractional Fourier transform. We derive the exact and approximated interference power, upper bound and measure of applicability for the AFT based multicarrier (AFT-MC) system. It is demonstrated that the AFT-MC system effectively minimizes interference in time-varying multipath channels with line-of-sight component and narrow beamwidth of scattered components that often occurs in aeronautical and satellite communications.

Abstract–In this paper, we study the uplink of a cellular network where reservation random access... more Abstract–In this paper, we study the uplink of a cellular network where reservation random access schemes such as reservation slotted ALOHA and reservation slotted nonpersistent ISMA are used for multiple access. When channel state information is not available to users when they contend for channel access, we find that capture effect inherent in wireless communications can exploit the channel variations and reserve users with favorable channels for data transmission. We investigate two channel models where in the first model, channel variations come from time-varying Nakagami-m fading and in the second model, mobile users have both time-varying fading and path loss. Index Terms–Random access, multiuser diversity, Nakagami-m fading I.

The SOPRANO project involves a novel adaptive and scalable wireless network architecture utilizin... more The SOPRANO project involves a novel adaptive and scalable wireless network architecture utilizing a mixture of cellular and multihop packet radio system topologies with potential to support a variety of applications including high data rate Internet and multimedia tra#c at a reasonable degree of implementation complexity. This article discusses the potential benefits of this structure and addresses several relevant issues necessary to support such a network. More specifically, it focuses on connection establishment and self-organization, investigates the formulation of an optimum transmission strategy, and examines some of the techniques by which we can augment the capacity or enhance the system performance in this multihop network. We also present capacity bounds which illustrate how these techniques help in trading o# conserved power for a multiple fold capacity advantage.

Preface. New Mobile Telephony in the Organisational Communication O. Galibert, et al. System Over... more Preface. New Mobile Telephony in the Organisational Communication O. Galibert, et al. System Overload and System Utilization - Myths and Realities D. McRae, et al. Experimental GSM Test Bed for Adaptive Array Antenna System G. Bucci, et al. High Speed Optical Data Link for Smart Antenna Mobile Radio System C. Savazzi. Spectrally Efficient Turbo Codes with Full Antenna Diversity H.-J. Su, E Geraniotis. A Novel DAB Technique Using Code Combining, Packet Combining, and Iterative Decoding (Turbo Code) B.K. Yi, et al. Multiple Access Using Periodic Clock Changes Through Slow Fading Multipath Channel A. Hayar, et al. On the Impact of Signal-Level-Based Power Control on Terminal Battery Duration M. Chiani, et al. Generalized Quasi-Walsh PN Sequences and Their Applications in Robust CDMA Communications Systems C. Giardina, A.N. Rudrapatna. Rate Processor Sharing: A Robust Technique for Scheduling Data Transmissions in CDMA Wireless Networks K. Kumaran, P. Whiting. The Initial Synchronisatio...

Preface. New Mobile Telephony in the Organisational Communication O. Galibert, et al. System Over... more Preface. New Mobile Telephony in the Organisational Communication O. Galibert, et al. System Overload and System Utilization - Myths and Realities D. McRae, et al. Experimental GSM Test Bed for Adaptive Array Antenna System G. Bucci, et al. High Speed Optical Data Link for Smart Antenna Mobile Radio System C. Savazzi. Spectrally Efficient Turbo Codes with Full Antenna Diversity H.-J. Su, E Geraniotis. A Novel DAB Technique Using Code Combining, Packet Combining, and Iterative Decoding (Turbo Code) B.K. Yi, et al. Multiple Access Using Periodic Clock Changes Through Slow Fading Multipath Channel A. Hayar, et al. On the Impact of Signal-Level-Based Power Control on Terminal Battery Duration M. Chiani, et al. Generalized Quasi-Walsh PN Sequences and Their Applications in Robust CDMA Communications Systems C. Giardina, A.N. Rudrapatna. Rate Processor Sharing: A Robust Technique for Scheduling Data Transmissions in CDMA Wireless Networks K. Kumaran, P. Whiting. The Initial Synchronisation Procedure in UMTS W-CDMA S. Kourtis. Iterative MMSE Multiuser Detection for Coded CDMA Channels with Multisensor Transmitter and Receiver Arrays J. Thomas, E. Geraniotis. Trading-off Capture Against Packet Separation for Throughput and Energy Efficiency in Random Access Systems W. Luo, A. Ephremides. The Concept of PARPS - Packet and Resource Plan Scheduling M. Eriksson, H. Saterberg. A Distributed Channel Allocation Method for Self-Organising Base Stations in a Wireless ATM Unlicensed System G.F. Marias, L. Merakos. Resource Allocation for Integrated Voice/WWW Traffic in UMTS/TDD Systems C. Mihailescu, et al. An Extended Error Control Technique for Wireless ATM Channel Z. Ilic, et al. Universal Platform for High-Speed Wireless OFDM Link Evaluation K.Verdijck. Seamless Multimedia Service for Third Generation Mobile Radio Networks M. Ferracioli, R. Verdone. Cell Assignability on Random Paths in CDMA Networks A. Leu, B. Jabbari. Key Issues in Handover Design and Multi-Layer Cellular System Design M. Lohi, et al. Configuration Data Verification and Design Techniques for Mobile Network Architecture Nodes D. D'Aurelio, et al. Investigation of Alternative ARQ Schemes for a Wireless ATM Network Architecture Nodes D. D'Aurelio, et al. Investigation of Alternative ARQ Schemes for a Wireless ATM Network D. Skyrianoglou, L. Merakos. Fair Sharing of MAC under TCP in Wireless Ad-hoc Networks K. Tang, M. Gerla. Fair Queueing Scheduler for IEEE 802.11 Based Wireless Multimedia Networks R.S. Ranasinghe, et al. Performance Analysis of a Cellular Slotted CDMA System with Imperfect Power Control over a Rayleigh Fading Channel J.M. Romero Jerez, et al. Efficiency Comparison Between CDMA and PRMA-HS in Low Earth Orbit Mobile Satellite Systems A. Abrardo, et al. Multiple Access Interference in Multi-beam CDMA-based LEO Satellite Systems H. Fu, et al. Capacity Considerations for Wireless MIMO Channels F. Boixadera Espax, J.J. Boutros. Determination of Critical Transmission Range in Ad-Hoc Networks M. Sanchez, et al. An Adaptive QoS Representation and Resource Allocation Scheme for Multimedia and Wireless ATM Networks Using Genetic Algorithms M.R. Sherif, et al.

Wirel Pers Commun, 1996

ABSTRACT

Ieee Globecom 2007 Ieee Global Telecommunications Conference, Nov 1, 2007

ABSTRACT Based on an analysis on the recursive computation of the iterative maximum a posteriori ... more ABSTRACT Based on an analysis on the recursive computation of the iterative maximum a posteriori (MAP) algorithm for turbo decoding, this paper considers a modified MAP scheme with reduced block lengths for symbols with unreliable detection after some initial iterations. Applying symbol selection based on cross-entropy measurement for parallel concatenated convolutional codes, we develop partial, windowed iterations for selected symbols. By omitting computations for symbols with reliable detection results, this approach significantly reduces complexity but well maintains the performance by complete iterations.

Ieee Transactions on Communications, Nov 1, 2009

Near-capacity performance of turbo codes is generally achieved with a large number of decoding it... more Near-capacity performance of turbo codes is generally achieved with a large number of decoding iterations. Various iteration stopping rules introduced in the literature often induce performance loss. This paper proposes a novel partial decoding iteration scheme using a bit-level convergence test. We first establish decoding optimality of windowed partial iteration for non-converged bits given that convergence has been achieved on window boundaries. We next present two criteria for testing bit convergence based on cross-entropy, and propose a windowed partial iteration algorithm. The overall complexity and memory requirements of the new algorithm are evaluated and compared with known algorithms. Simulations reveal that the proposed scheme suffers essentially no performance loss compared to full iterations, while reducing the decoding complexity. We also briefly discuss possible extensions of the proposed scheme to general iterative receivers.

Acoustics Speech and Signal Processing 1988 Icassp 88 1988 International Conference on, 2009

ABSTRACT This paper proposes a bit-selective iterative processing scheme for turbo equalization. ... more ABSTRACT This paper proposes a bit-selective iterative processing scheme for turbo equalization. We consider convolutionally coded and turbo coded transmissions over inter-symbol interference (ISI) channels. The receiver starts with conventional iterative channel equalization and decoding. After each iteration, bit convergence status is measured via cross-entropy. Short windows are then applied around unconverged bits and the subsequent detection/decoding iterates only within the windows. The rapid decrease in selected bits after each such iteration reduces computational complexity significantly, but performance is well maintained by utilizing the Markov property in the trellis detection/decoding.

Ieee Transactions on Wireless Communications, Jun 1, 2009

Multicarrier techniques based on affine Fourier transform (AFT) have been recently proposed for t... more Multicarrier techniques based on affine Fourier transform (AFT) have been recently proposed for transmission in the wireless channels. The AFT represents a generalization of the Fourier and fractional Fourier transform. We derive the exact and approximated interference power, upper bound and measure of applicability for the AFT based multicarrier (AFT-MC) system. It is demonstrated that the AFT-MC system effectively minimizes interference in time-varying multipath channels with line-of-sight component and narrow beamwidth of scattered components that often occurs in aeronautical and satellite communications.