The Experts below are selected from a list of 94785 Experts worldwide ranked by ideXlab platform
Jong-wha Chong - One of the best experts on this subject based on the ideXlab platform.
-
Improved Design Criterion for space-time trellis codes over time-correlated Rayleigh fading channels
IEEE 60th Vehicular Technology Conference 2004. VTC2004-Fall. 2004, 2004Co-Authors: Jong-wha ChongAbstract:In this paper, an improved Design Criterion for space-time trellis codes over time-correlated Rayleigh fading channels is presented. We decompose the time-correlated fading channel into two independent components: slow fading channel and fast fading channel. The code Design problem for time-correlated fading channels is converted to the joint Design both in slow fading channels and in fast fading channels, while no knowledge about correlation is needed. Simulation results are provided to confirm our theory.
Helio Leaes Hey - One of the best experts on this subject based on the ideXlab platform.
-
A unified Design Criterion for ZVT DC-DC PWM converters with constant auxiliary Voltage source
IEEE Transactions on Industrial Electronics, 2005Co-Authors: Jumar Luis Russi, Hilton Abilio Grundling, Humberto Pinheiro, Jose Renes Pinheiro, M.ld.s. Martins, Helio Leaes HeyAbstract:This paper proposes a Design Criterion for calculating the resonant auxiliary elements of zero-voltage transition dc-dc pulsewidth-modulated (PWM) converters that use a dc auxiliary voltage source. The proposed Criterion is based on stored energy in resonant auxiliary elements and takes into account the influence of the auxiliary voltage source value. Using this Criterion, the reactive energy can be kept at a minimum level and a reduction of the auxiliary elements current ratings is achieved, which leads to lower conduction losses and improved converter efficiency. In addition, a reduction in size of auxiliary magnetic elements can be accomplished. To illustrate the usefulness of the proposed Design Criterion, the paper compares results obtained from the True-PWM Zero-Voltage Switching pole boost converter Designed according to the proposed Criterion, and from the original Design guidelines. Experimental results show an efficiency gain of about 1% for a wide load range and 1.5% at full load. In addition, a reduction of about 52% in the auxiliary transformer volume for the implemented prototype was achieved, ensuring a reduction in overall converter size. Experimental results were obtained using a 1-kW 100-kHz laboratory prototype.
-
A Design Criterion to ZVT DC-DC PWM converters with constant auxiliary voltage source
2003 IEEE International Symposium on Industrial Electronics ( Cat. No.03TH8692), 2003Co-Authors: Jumar Luis Russi, Mario Lucio Da Silva Martins, Hilton Abilio Grundling, Humberto Pinheiro, Jose Renes Pinheiro, Helio Leaes HeyAbstract:This paper proposes a Design Criterion to calculate the resonant auxiliary elements of ZVT DC-DC PWM converters that use a DC auxiliary voltage source. The proposed Criterion is based on stored energy in resonant auxiliary elements and takes into account the influence of the auxiliary voltage source value. By means of this Criterion the reactive energy can be kept at a minimum level and a reduction of the auxiliary elements current ratings is achieved, which leads to lower conduction losses and improved converter efficiency. In addition, a reduction in auxiliary magnetic elements size can be accomplished. To illustrate the usefulness of the Design Criterion proposed, comparative results obtained from the true pulse-width modulated (PWM) zero-voltage switching (ZVS) pole boost converter Designed by proposed Criterion and its original Design guidelines are presented. Experimental results show an efficiency gain of about 1% for a wide range and 1.5% at full load. In addition, a reduction of about 52% in the auxiliary transformer volume for the implemented prototype was achieved, ensuring a reduction in overall converter size. Experimental results were obtained from 1 kW, 100 kHz laboratory prototype.
Jumar Luis Russi - One of the best experts on this subject based on the ideXlab platform.
-
A unified Design Criterion for ZVT DC-DC PWM converters with constant auxiliary Voltage source
IEEE Transactions on Industrial Electronics, 2005Co-Authors: Jumar Luis Russi, Hilton Abilio Grundling, Humberto Pinheiro, Jose Renes Pinheiro, M.ld.s. Martins, Helio Leaes HeyAbstract:This paper proposes a Design Criterion for calculating the resonant auxiliary elements of zero-voltage transition dc-dc pulsewidth-modulated (PWM) converters that use a dc auxiliary voltage source. The proposed Criterion is based on stored energy in resonant auxiliary elements and takes into account the influence of the auxiliary voltage source value. Using this Criterion, the reactive energy can be kept at a minimum level and a reduction of the auxiliary elements current ratings is achieved, which leads to lower conduction losses and improved converter efficiency. In addition, a reduction in size of auxiliary magnetic elements can be accomplished. To illustrate the usefulness of the proposed Design Criterion, the paper compares results obtained from the True-PWM Zero-Voltage Switching pole boost converter Designed according to the proposed Criterion, and from the original Design guidelines. Experimental results show an efficiency gain of about 1% for a wide load range and 1.5% at full load. In addition, a reduction of about 52% in the auxiliary transformer volume for the implemented prototype was achieved, ensuring a reduction in overall converter size. Experimental results were obtained using a 1-kW 100-kHz laboratory prototype.
-
A Design Criterion to ZVT DC-DC PWM converters with constant auxiliary voltage source
2003 IEEE International Symposium on Industrial Electronics ( Cat. No.03TH8692), 2003Co-Authors: Jumar Luis Russi, Mario Lucio Da Silva Martins, Hilton Abilio Grundling, Humberto Pinheiro, Jose Renes Pinheiro, Helio Leaes HeyAbstract:This paper proposes a Design Criterion to calculate the resonant auxiliary elements of ZVT DC-DC PWM converters that use a DC auxiliary voltage source. The proposed Criterion is based on stored energy in resonant auxiliary elements and takes into account the influence of the auxiliary voltage source value. By means of this Criterion the reactive energy can be kept at a minimum level and a reduction of the auxiliary elements current ratings is achieved, which leads to lower conduction losses and improved converter efficiency. In addition, a reduction in auxiliary magnetic elements size can be accomplished. To illustrate the usefulness of the Design Criterion proposed, comparative results obtained from the true pulse-width modulated (PWM) zero-voltage switching (ZVS) pole boost converter Designed by proposed Criterion and its original Design guidelines are presented. Experimental results show an efficiency gain of about 1% for a wide range and 1.5% at full load. In addition, a reduction of about 52% in the auxiliary transformer volume for the implemented prototype was achieved, ensuring a reduction in overall converter size. Experimental results were obtained from 1 kW, 100 kHz laboratory prototype.
Michael P. Fitz - One of the best experts on this subject based on the ideXlab platform.
-
Hybrid ARQ in Multiple-Antenna Slow Fading Channels: Performance Limits and Optimal Linear Dispersion Code Design
IEEE Transactions on Information Theory, 2011Co-Authors: Cong Shen, Michael P. FitzAbstract:This paper focuses on studying the fundamental performance limits and linear dispersion code Design for the MIMO-ARQ slow fading channel. The optimal average rate of well-known HARQ protocols is analyzed. The optimal Design of space-time coding for the MIMO-ARQ channel is discussed. Information-theoretic measures are used to optimize the rate assignment and derive the optimum Design Criterion, which is then used to evaluate the optimality of existing space-time codes. A different Design Criterion, which is obtained from the error probability analysis of space-time coded MIMO-HARQ, is presented. Examples are studied to reveal the gain of ARQ feedback in space-time coded MIMO systems.
-
hybrid arq in multiple antenna slow fading channels performance limits and optimal linear dispersion code Design
arXiv: Information Theory, 2009Co-Authors: Cong Shen, Michael P. FitzAbstract:This paper focuses on studying the fundamental performance limits and linear dispersion code Design for the MIMO-ARQ slow fading channel. Optimal average rate of well-known HARQ protocols is analyzed. The optimal Design of space-time coding for the MIMO-ARQ channel is discussed. Information-theoretic measures are used to optimize the rate assignment and derive the optimum Design Criterion, which is then used to evaluate the optimality of existing space-time codes. A different Design Criterion, which is obtained from the error probability analysis of space-time coded MIMO-HARQ, is presented. Examples are studied to reveal the gain of ARQ feedback in space-time coded MIMO systems.
Wen-rong Wu - One of the best experts on this subject based on the ideXlab platform.
-
GLOBECOM - X-structured precoder Design for spatial multiplexing MIMO systems
2012 IEEE Global Communications Conference (GLOBECOM), 2012Co-Authors: Wen-rong WuAbstract:In multiple-input multiple-output (MIMO) transmission, precoding has been considered a promising method to improve the system performance. In general, the precoder Design Criterion depends on the detector used at the receiver. For the maximum-likelihood (ML) detector, the optimum precoder Design Criterion is equivalent to maximizing the minimum distance of received signal constellations. Several precoding methods have been developed in the literature. However, most of them use numerical searches to derive the precoders and require table look-ups in realtime applications. In this paper, we propose a simple but effective method to solve the problem. The proposed precoder has a simple closed-form expression and no tables are required to store. Simulation results show that the proposed precoder can provide almost the same performance as existing precoders.
-
x structured precoder Design for spatial multiplexing mimo systems
Global Communications Conference, 2012Co-Authors: Wen-rong WuAbstract:In multiple-input multiple-output (MIMO) transmission, precoding has been considered a promising method to improve the system performance. In general, the precoder Design Criterion depends on the detector used at the receiver. For the maximum-likelihood (ML) detector, the optimum precoder Design Criterion is equivalent to maximizing the minimum distance of received signal constellations. Several precoding methods have been developed in the literature. However, most of them use numerical searches to derive the precoders and require table look-ups in realtime applications. In this paper, we propose a simple but effective method to solve the problem. The proposed precoder has a simple closed-form expression and no tables are required to store. Simulation results show that the proposed precoder can provide almost the same performance as existing precoders.
