The Experts below are selected from a list of 26691 Experts worldwide ranked by ideXlab platform

Heung Ki Baik - One of the best experts on this subject based on the ideXlab platform.

  • shannon capacity and symbol Error rate of space time block codes in mimo rayleigh Channels with Channel Estimation Error
    IEEE Transactions on Wireless Communications, 2008
    Co-Authors: Robert W Heath, Heung Ki Baik
    Abstract:

    Space-time block coding (STBC) is an attractive solution for improving quality in wireless links. In this paper, we analyze the impact of Channel Estimation Error on the ergodic capacity and symbol Error rate (SER) for space-time block coded multiple-input multiple-output (MIMO) systems. We derive a closed-form capacity expression over MIMO Rayleigh Channels with Channel Estimation Error. Moreover, we derive an exact closed-form SER for general PAM/PSK/QAM with Channel Estimation Error. We show that, as expected, Channel Estimation Error introduces the capacity loss and diversity gain loss. Furthermore, as the number of transmit and receive antennas increases, the sensitivity of the STBC system to Channel Estimation Error increases. Simulation results demonstrate the accuracy of our analysis.

N.a. Kumar - One of the best experts on this subject based on the ideXlab platform.

  • The impact of Channel Estimation Error on space-time block codes
    Proceedings IEEE 56th Vehicular Technology Conference, 1
    Co-Authors: R.m. Buehrer, N.a. Kumar
    Abstract:

    We examine the impact of Channel Estimation Error on the performance of 2 and 4 antenna space-time block codes. This is examined specifically in the context of space-time spreading as defined for the cdma2000 standard. The performance is determined by finding an expression for the probability of bit Error when using BPSK or QPSK modulation and modeling the Channel Estimation Error as a Gaussian random variable.

Lei Zhang - One of the best experts on this subject based on the ideXlab platform.

  • massive mimo performance with imperfect Channel reciprocity and Channel Estimation Error
    IEEE Transactions on Communications, 2017
    Co-Authors: Mehrdad Dianati, Lei Zhang, Sami Muhaidat, Rahim Tafazolli
    Abstract:

    Channel reciprocity in time-division duplexing (TDD) massive multiple-input multiple-output (MIMO) systems can be exploited to reduce the overhead required for the acquisition of Channel state information (CSI). However, perfect reciprocity is unrealistic in practical systems due to random radio-frequency (RF) circuit mismatches in uplink and downlink Channels. This can result in a significant degradation in the performance of linear precoding schemes, which are sensitive to the accuracy of the CSI. In this paper, we model and analyse the impact of RF mismatches on the performance of linear precoding in a TDD multi-user massive MIMO system, by taking the Channel Estimation Error into considerations. We use the truncated Gaussian distribution to model the RF mismatch, and derive closed-form expressions of the output signal-to-interference-plus-noise ratio for maximum ratio transmission and zero forcing precoders. We further investigate the asymptotic performance of the derived expressions, to provide valuable insights into the practical system designs, including useful guidelines for the selection of the effective precoding schemes. Simulation results are presented to demonstrate the validity and accuracy of the proposed analytical results.

  • optimal uplink pilot time interval design for tdd miso beamforming systems with Channel Estimation Error and delay
    International Conference on Communications, 2011
    Co-Authors: Baolong Zhou, Lingge Jiang, Lei Zhang, Shengjie Zhao, Kun Zhao
    Abstract:

    This paper proposes an optimization scheme on uplink pilots time interval (UPTI) in terms of maximum average post-processing SNR (signal to noise ratio) for a time division duplex (TDD) multiple input single output (MISO) beamforming system with Channel Estimation Error and delay. In TDD system, the base station estimates the Channel state information (CSI) at transmitter based on uplink pilots and then uses it to generate the beamforming vector in the downlink transmission. Because of the constraints of the TDD frame structure and the uplink pilot overhead, there inevitably exists delay and Channel Estimation Error between CSI Estimation and its use. In this paper, we first derive average post-processing SNR for TDD MISO beamforming system with Channel Estimation Error and delay. We then obtain the optimal UPTI, which maximizes average post-processing SNR, given the normalized pilot overhead (the number of pilot symbols per data symbol). The simulation results validate that the optimal UPTI not only maximizes the average post-processing SNR but also maximizes the system ergodic rate. Especially our research is valuable for the uplink sounding reference signal design in LTE-Advanced system. Index Terms—Channel Estimation Error, delay, multiple input single output (MISO), time division duplex (TDD)

  • VTC Spring - On BER of TDD Multiuser MIMO System with Channel Estimation Error and Delay
    2011 IEEE 73rd Vehicular Technology Conference (VTC Spring), 2011
    Co-Authors: Baolong Zhou, Lingge Jiang, Lei Zhang, Shengjie Zhao, Lingfeng Lin
    Abstract:

    In Multiuser Multiple-Input Multiple-Output (MU-MIMO) downlink systems, the zero-forcing algorithm is a simple and effective technique for separating users and data streams of each user at the transmitter side, but its performance depends greatly on the accuracy of the available Channel state information (CSI) at the transmitter. Due to the existence of the CSI delay and Channel Estimation Error in practical systems, CSI is always imperfect, which degrades system performance significantly. In this paper, by using the correlation between the actual Channel and the estimated one as well as the Channel's time-correlation, we develop a novel bit Error rate (BER) expression for M-QAM (quadrature amplitude modulation) signal in time division duplex (TDD) downlink MU-MIMO system with Channel Estimation Error and CSI delay. We find that Channel Estimation Error causes array gain loss while CSI delay causes diversity gain loss. Moreover, CSI delay causes more performance degradation than Channel Estimation Error at high signal to noise ratio (SNR) for time varying Channel. Especially our research is valuable for adaptive modulation and coding scheme and the optimization of MU-MIMO system. Numerical simulations show accurate agreement with the analytical expressions.

  • VTC Spring - Capacity of TDD MISO Beamforming Systems with Channel Estimation Error and Delay
    2011 IEEE 73rd Vehicular Technology Conference (VTC Spring), 2011
    Co-Authors: Baolong Zhou, Lingge Jiang, Lei Zhang, Shengjie Zhao, Kun Zhao, Zhining Jiang
    Abstract:

    This paper examines the capacity of a time division duplex (TDD) multiple input single output (MISO) beamforming system with Channel Estimation Error and delay over the time varying fading Channel. In TDD system, the base station estimates the Channel state information (CSI) at transmitter based on uplink pilots and then uses it to generate the beamforming vector in the downlink transmission. Because of the constraints of the TDD frame structure and the uplink pilot overhead, there inevitably exists delay and Channel Estimation Error between CSI Estimation and its use. In this paper, we first derive the capacity upper bound for TDD MISO beamforming system with Channel Estimation Error and delay. We then obtain the optimal uplink pilot time interval (UPTI), which maximizes the capacity upper bound, given the normalized pilot overhead (the number of pilot symbols per data symbol). The simulation results validate that the optimal UPTI not only maximizes the capacity upper bound but also maximizes the system ergodic capacity. Especially our research is valuable for the uplink sounding reference signal design in LTE- Advanced system.

Baolong Zhou - One of the best experts on this subject based on the ideXlab platform.

  • optimal uplink pilot time interval design for tdd miso beamforming systems with Channel Estimation Error and delay
    International Conference on Communications, 2011
    Co-Authors: Baolong Zhou, Lingge Jiang, Lei Zhang, Shengjie Zhao, Kun Zhao
    Abstract:

    This paper proposes an optimization scheme on uplink pilots time interval (UPTI) in terms of maximum average post-processing SNR (signal to noise ratio) for a time division duplex (TDD) multiple input single output (MISO) beamforming system with Channel Estimation Error and delay. In TDD system, the base station estimates the Channel state information (CSI) at transmitter based on uplink pilots and then uses it to generate the beamforming vector in the downlink transmission. Because of the constraints of the TDD frame structure and the uplink pilot overhead, there inevitably exists delay and Channel Estimation Error between CSI Estimation and its use. In this paper, we first derive average post-processing SNR for TDD MISO beamforming system with Channel Estimation Error and delay. We then obtain the optimal UPTI, which maximizes average post-processing SNR, given the normalized pilot overhead (the number of pilot symbols per data symbol). The simulation results validate that the optimal UPTI not only maximizes the average post-processing SNR but also maximizes the system ergodic rate. Especially our research is valuable for the uplink sounding reference signal design in LTE-Advanced system. Index Terms—Channel Estimation Error, delay, multiple input single output (MISO), time division duplex (TDD)

  • VTC Spring - On BER of TDD Multiuser MIMO System with Channel Estimation Error and Delay
    2011 IEEE 73rd Vehicular Technology Conference (VTC Spring), 2011
    Co-Authors: Baolong Zhou, Lingge Jiang, Lei Zhang, Shengjie Zhao, Lingfeng Lin
    Abstract:

    In Multiuser Multiple-Input Multiple-Output (MU-MIMO) downlink systems, the zero-forcing algorithm is a simple and effective technique for separating users and data streams of each user at the transmitter side, but its performance depends greatly on the accuracy of the available Channel state information (CSI) at the transmitter. Due to the existence of the CSI delay and Channel Estimation Error in practical systems, CSI is always imperfect, which degrades system performance significantly. In this paper, by using the correlation between the actual Channel and the estimated one as well as the Channel's time-correlation, we develop a novel bit Error rate (BER) expression for M-QAM (quadrature amplitude modulation) signal in time division duplex (TDD) downlink MU-MIMO system with Channel Estimation Error and CSI delay. We find that Channel Estimation Error causes array gain loss while CSI delay causes diversity gain loss. Moreover, CSI delay causes more performance degradation than Channel Estimation Error at high signal to noise ratio (SNR) for time varying Channel. Especially our research is valuable for adaptive modulation and coding scheme and the optimization of MU-MIMO system. Numerical simulations show accurate agreement with the analytical expressions.

  • VTC Spring - Capacity of TDD MISO Beamforming Systems with Channel Estimation Error and Delay
    2011 IEEE 73rd Vehicular Technology Conference (VTC Spring), 2011
    Co-Authors: Baolong Zhou, Lingge Jiang, Lei Zhang, Shengjie Zhao, Kun Zhao, Zhining Jiang
    Abstract:

    This paper examines the capacity of a time division duplex (TDD) multiple input single output (MISO) beamforming system with Channel Estimation Error and delay over the time varying fading Channel. In TDD system, the base station estimates the Channel state information (CSI) at transmitter based on uplink pilots and then uses it to generate the beamforming vector in the downlink transmission. Because of the constraints of the TDD frame structure and the uplink pilot overhead, there inevitably exists delay and Channel Estimation Error between CSI Estimation and its use. In this paper, we first derive the capacity upper bound for TDD MISO beamforming system with Channel Estimation Error and delay. We then obtain the optimal uplink pilot time interval (UPTI), which maximizes the capacity upper bound, given the normalized pilot overhead (the number of pilot symbols per data symbol). The simulation results validate that the optimal UPTI not only maximizes the capacity upper bound but also maximizes the system ergodic capacity. Especially our research is valuable for the uplink sounding reference signal design in LTE- Advanced system.

Akihiro Kajiwara - One of the best experts on this subject based on the ideXlab platform.

  • Time-reversal UWB-IR considering Channel Estimation Error
    2013 IEEE Topical Conference on Power Amplifiers for Wireless and Radio Applications, 2013
    Co-Authors: H. Ishikawa, A. Matsumoto, Ryohei Nakamura, Akihiro Kajiwara
    Abstract:

    Recently, there is a great demand for gigabit short-range UWB-IR communications where the system simplicity and low power consumption are required for each terminal. For the down link, however, Rake reception should be necessary to attain the required Eb/ N0 since the power emission is limited to 41.3dBm/MHz. Therefore, UWB-IR with time-reversal transmission (TiR) has gained much attention because the terminal system complexity may be largely reduced with respect to the correlation and Rake combining process. However this scheme is very sensitive to the Channel Estimation Error. There have been several papers on TiR UWB-IR communications, but the effect of Channel Estimation Error on the performance had not been considered. In this paper, the measurement was conducted where the Channel Estimation Error is discussed. Also the effect of TiR filter length is discussed to suppress the Estimation Error.

  • RWS - Time-reversal UWB-IR considering Channel Estimation Error
    2013 IEEE Radio and Wireless Symposium, 2013
    Co-Authors: H. Ishikawa, A. Matsumoto, Ryohei Nakamura, Akihiro Kajiwara
    Abstract:

    Recently, there is a great demand for gigabit short-range UWB-IR communications where the system simplicity and low power consumption are required for each terminal. For the down link, however, Rake reception should be necessary to attain the required Eb/N0 since the power emission is limited to -41.3dBm/MHz. Therefore, UWB-IR with time-reversal transmission (TiR) has gained much attention because the terminal system complexity may be largely reduced with respect to the correlation and Rake combining process. However this scheme is very sensitive to the Channel Estimation Error. There have been several papers on TiR UWB-IR communications, but the effect of Channel Estimation Error on the performance had not been considered. In this paper, the measurement was conducted where the Channel Estimation Error is discussed. Also the effect of TiR filter length is discussed to suppress the Estimation Error.

  • WiSNet - Time-reversal UWB-IR considering Channel Estimation Error
    2013 IEEE Topical Conference on Wireless Sensors and Sensor Networks (WiSNet), 2013
    Co-Authors: H. Ishikawa, A. Matsumoto, Ryohei Nakamura, Akihiro Kajiwara
    Abstract:

    Recently, there is a great demand for gigabit short-range UWB-IR communications where the system simplicity and low power consumption are required for each terminal. For the down link, however, Rake reception should be necessary to attain the required Eb/N0 since the power emission is limited to -41.3dBm/MHz. Therefore, UWB-IR with time-reversal transmission (TiR) has gained much attention because the terminal system complexity may be largely reduced with respect to the correlation and Rake combining process. However this scheme is very sensitive to the Channel Estimation Error. There have been several papers on TiR UWB-IR communications, but the effect of Channel Estimation Error on the performance had not been considered. In this paper, the measurement was conducted where the Channel Estimation Error is discussed. Also the effect of TiR filter length is discussed to suppress the Estimation Error.