The Experts below are selected from a list of 909 Experts worldwide ranked by ideXlab platform

Alexander Gluhak - One of the best experts on this subject based on the ideXlab platform.

  • Codebook Based Single-User MIMO System Design with Widely Linear Processing
    IEEE Transactions on Communications, 2012
    Co-Authors: Pei Xiao, Rahim Tafazolli, Klaus Moessner, Alexander Gluhak
    Abstract:

    This work addresses joint transceiver optimization for multiple-input, multiple-output (MIMO) systems. In practical systems the complete knowledge of Channel state information (CSI) is hardly available at transmitter. To tackle this problem, we resort to the codebook approach to precoding design, where the receiver selects a precoding matrix from a finite set of pre-defined precoding matrices based on the Instantaneous Channel Condition and delivers the index of the chosen precoding matrix to the transmitter via a bandwidth-constraint feedback Channel. We show that, when the symbol constellation is improper, the joint codebook based precoding and equalization can be designed accordingly to achieve improved performance compared to the conventional system.

Pei Xiao - One of the best experts on this subject based on the ideXlab platform.

  • Optimization of MIMO Transceiver with Limited Feedback Channel
    2016
    Co-Authors: Pei Xiao, Qingchun Chen
    Abstract:

    Abstract—This work addresses joint transceiver optimization for multiple-input, multiple-output (MIMO) systems. In practical systems the complete knowledge of Channel state information (CSI) is hardly available at transmitter. To tackle this problem, we resort to the codebook approach to precoding design, where the receiver selects a precoding matrix from a finite set of pre-defined precoding matrices based on the Instantaneous Channel Condition and delivers the index of the chosen precoding matrix to the transmitter via a bandwidth-constraint feedback Channel. In this paper, the codebook based precoding design at transmitter is optimized jointly with decoding design at receiver. I

  • Codebook Based Single-User MIMO System Design with Widely Linear Processing
    IEEE Transactions on Communications, 2012
    Co-Authors: Pei Xiao, Rahim Tafazolli, Klaus Moessner, Alexander Gluhak
    Abstract:

    This work addresses joint transceiver optimization for multiple-input, multiple-output (MIMO) systems. In practical systems the complete knowledge of Channel state information (CSI) is hardly available at transmitter. To tackle this problem, we resort to the codebook approach to precoding design, where the receiver selects a precoding matrix from a finite set of pre-defined precoding matrices based on the Instantaneous Channel Condition and delivers the index of the chosen precoding matrix to the transmitter via a bandwidth-constraint feedback Channel. We show that, when the symbol constellation is improper, the joint codebook based precoding and equalization can be designed accordingly to achieve improved performance compared to the conventional system.

Kee Chaing Chua - One of the best experts on this subject based on the ideXlab platform.

  • wireless information and power transfer a dynamic power splitting approach
    IEEE Transactions on Communications, 2013
    Co-Authors: Rui Zhang, Kee Chaing Chua
    Abstract:

    Energy harvesting is a promising solution to prolong the operation time of energy-constrained wireless networks. In particular, scavenging energy from ambient radio signals, namely wireless energy harvesting (WEH), has recently drawn significant attention. In this paper, we consider a point-to-point wireless link over the flat-fading Channel, where the receiver has no fixed power supplies and thus needs to replenish energy via WEH from the signals sent by the transmitter. We first consider a SISO (single-input single-output) system where the single-antenna receiver cannot decode information and harvest energy independently from the same signal received. Under this practical constraint, we propose a dynamic power splitting (DPS) scheme, where the received signal is split into two streams with adjustable power levels for information decoding and energy harvesting separately based on the Instantaneous Channel Condition that is assumed to be known at the receiver. We derive the optimal power splitting rule at the receiver to achieve various trade-offs between the maximum ergodic capacity for information transfer and the maximum average harvested energy for power transfer, which are characterized by the boundary of a so-called "rate-energy (R-E)" region. Moreover, for the case when the Channel state information is also known at the transmitter, we investigate the joint optimization of transmitter power control and receiver power splitting. The achievable R-E region by the proposed DPS scheme is also compared against that by the existing time switching scheme as well as a performance upper bound by ignoring the practical receiver constraint. Finally, we extend the result for optimal DPS to the SIMO (single-input multiple-output) system where the receiver is equipped with multiple antennas. In particular, we investigate a low-complexity power splitting scheme, namely antenna switching, which achieves the near-optimal rate-energy trade-offs as compared to the optimal DPS.

Zhifeng Chen - One of the best experts on this subject based on the ideXlab platform.

  • rate distortion optimized cross layer rate control in wireless video communication
    IEEE Transactions on Circuits and Systems for Video Technology, 2012
    Co-Authors: Zhifeng Chen
    Abstract:

    A wireless video communication system can be designed based on the rate-distortion (R-D) criterion, i.e., minimizing the end-to-end distortion (which includes quantization distortion and transmission distortion) subject to the transmission bit-rate constraint. The minimization can be achieved by adjusting the source encoding parameters and Channel encoding parameters. This rate-distortion optimization (RDO) is usually done for each video frame individually in a real-time video communication system, e.g., video calls or videoconferencing. To achieve this, an accurate bit-rate model and distortion model for each frame can be used to reduce the RDO complexity. In this paper, we derive a source bit-rate model and quantization distortion model; we also improve the performance bound for Channel coding under a convolutional code and a Viterbi decoder, and derive its performance bound under a Rayleigh block fading Channel. Given the Instantaneous Channel Condition, e.g., signal-to-noise ratio and transmission bit-rate constraint, we design an R-D optimized cross-layer rate control (CLRC) algorithm by jointly choosing quantization step size in source coding and code rate in Channel coding. Experimental results show that our proposed R-D models are more accurate than the existing R-D models. Experimental results also showed that the rate control under our models has more stable R-D performance than the existing rate control algorithms; using the Channel estimation, CLRC can further achieve remarkable R-D performance gain over that without Channel estimation. Another important result is that the subjective quality of our CLRC algorithm is much better than the existing algorithms due to its intelligent reference frame selection.

  • Rate-Distortion Optimized Cross-layer Rate Control in Wireless Video Communication
    2011
    Co-Authors: Zhifeng Chen
    Abstract:

    A wireless video communication system can be designed based on the rate-distortion (R-D) criterion, i.e., minimizing the end-to-end distortion (which includes quantization distortion and transmission distortion) subject to the transmission bit-rate constraint. The minimization can be achieved by adjusting the source encoding parameters and Channel encoding parameters. This R-D optimization (RDO) is usually done for each video frame individually in a real-time video communication system, e.g. video calls or videoconferencing. To achieve this, an accurate bit-rate model and distortion model for each frame can be used to reduce the RDO complexity. In this paper, we derive a source bit-rate model and quantization distortion model; we also improve the performance bound for Channel coding under a convolutional code and a Viterbi decoder, and derive its performance bound under a Rayleigh block fading Channel. Given the Instantaneous Channel Condition, e.g., signal-to-noise ratio (SNR) and transmission bit-rate constraint, we design an R-D optimized cross-layer rate control (CLRC) algorithm by jointly choosing quantization step size in source coding and code rate in Channel coding. Experimental results show that our proposed R-D models are more accurate than the existing R-D models. Experimental results also showed that the rate control under our models has more stable R-D performance than the existing rate control algorithms; using the Channel estimation, CLRC can further achieve remarkable R-D performance gain over that without Channel estimation. Another important result is that the subjective quality of our CLRC algorithm is much better than the existing algorithms due to its intelligent reference frame selection

Rahim Tafazolli - One of the best experts on this subject based on the ideXlab platform.

  • Codebook Based Single-User MIMO System Design with Widely Linear Processing
    IEEE Transactions on Communications, 2012
    Co-Authors: Pei Xiao, Rahim Tafazolli, Klaus Moessner, Alexander Gluhak
    Abstract:

    This work addresses joint transceiver optimization for multiple-input, multiple-output (MIMO) systems. In practical systems the complete knowledge of Channel state information (CSI) is hardly available at transmitter. To tackle this problem, we resort to the codebook approach to precoding design, where the receiver selects a precoding matrix from a finite set of pre-defined precoding matrices based on the Instantaneous Channel Condition and delivers the index of the chosen precoding matrix to the transmitter via a bandwidth-constraint feedback Channel. We show that, when the symbol constellation is improper, the joint codebook based precoding and equalization can be designed accordingly to achieve improved performance compared to the conventional system.