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Hai Lin - One of the best experts on this subject based on the ideXlab platform.

  • high mobility wideband massive mimo communications doppler compensation analysis and scaling laws
    IEEE Transactions on Wireless Communications, 2019
    Co-Authors: Wei Guo, Weile Zhang, Feifei Gao, Hai Lin
    Abstract:

    In this paper, we apply angle-domain Doppler compensation for high-mobility wideband massive multi-input multi-output (MIMO) uplink communications. The time-varying multipath Channel is considered between high-speed terminal and static base station (BS), where multiple Doppler frequency offsets (DFOs) are associated with distinct angle of departures (AoDs). With the aid of large-scale uniform linear array (ULA) at the transmitter, we design a beamforming network to generate multiple parallel beamforming branches, each transmitting signal pointing to one particular angle. Then, the transmitted signal in each branch will experience only one dominant DFO when passing over the time-varying Channel, which can be easily compensated before transmission starts. We theoretically analyze the Doppler spread of the equivalent uplink Channel after angle-domain Doppler compensation, which takes into account both the mainlobe and sidelobes of the transmit beam in each branch. It is seen that the Channel time-Variation can be effectively suppressed if the number of transmit antennas is sufficiently large. Interestingly, the asymptotic scaling law of Channel Variation is obtained, which shows that the Doppler spread is proportional to the maximum DFO and decreases approximately as $1/\sqrt {M}$ ( $M$ is the number of transmit antennas) when $M$ is sufficiently large. The numerical results are provided to corroborate the proposed scheme.

  • high mobility wideband massive mimo communications doppler compensation analysis and scaling law
    arXiv: Information Theory, 2018
    Co-Authors: Wei Guo, Weile Zhang, Feifei Gao, Hai Lin
    Abstract:

    In this paper, we apply angle-domain Doppler compensation for high-mobility wideband massive multi-input multi-output (MIMO) uplink transmission. The time-varying multipath Channel is considered between high-speed terminal and static base station (BS), where multiple Doppler frequency offsets (DFOs) are associated with distinct angle of departures (AoDs). With the aid of the large-scale uniform linear array (ULA) at the transmitter, we design a beamforming network to generate multiple parallel beamforming branches, each transmitting signal pointing to one particular angle. Then, the transmitted signal in each branch will experience only one dominant DFO when passing over the time-varying Channel, which can be easily compensated before transmission starts. We theoretically analyze the Doppler spread of the equivalent uplink Channel after angle-domain Doppler compensation, which takes into account both the mainlobe and sidelobes of the transmit beam in each branch. It is seen that the Channel time-Variation can be effectively suppressed if the number of transmit antennas is sufficiently large. Interestingly, the asymptotic scaling law of Channel Variation is obtained, which shows that the Doppler spread is proportional to the maximum DFO and decreases approximately as $1/\sqrt{M}$ ($M$ is the number of transmit antennas) when $M$ is sufficiently large. Numerical results are provided to corroborate the proposed scheme.

Feifei Gao - One of the best experts on this subject based on the ideXlab platform.

  • high mobility wideband massive mimo communications doppler compensation analysis and scaling laws
    IEEE Transactions on Wireless Communications, 2019
    Co-Authors: Wei Guo, Weile Zhang, Feifei Gao, Hai Lin
    Abstract:

    In this paper, we apply angle-domain Doppler compensation for high-mobility wideband massive multi-input multi-output (MIMO) uplink communications. The time-varying multipath Channel is considered between high-speed terminal and static base station (BS), where multiple Doppler frequency offsets (DFOs) are associated with distinct angle of departures (AoDs). With the aid of large-scale uniform linear array (ULA) at the transmitter, we design a beamforming network to generate multiple parallel beamforming branches, each transmitting signal pointing to one particular angle. Then, the transmitted signal in each branch will experience only one dominant DFO when passing over the time-varying Channel, which can be easily compensated before transmission starts. We theoretically analyze the Doppler spread of the equivalent uplink Channel after angle-domain Doppler compensation, which takes into account both the mainlobe and sidelobes of the transmit beam in each branch. It is seen that the Channel time-Variation can be effectively suppressed if the number of transmit antennas is sufficiently large. Interestingly, the asymptotic scaling law of Channel Variation is obtained, which shows that the Doppler spread is proportional to the maximum DFO and decreases approximately as $1/\sqrt {M}$ ( $M$ is the number of transmit antennas) when $M$ is sufficiently large. The numerical results are provided to corroborate the proposed scheme.

  • deep learning based Channel estimation for doubly selective fading Channels
    IEEE Access, 2019
    Co-Authors: Yuwen Yang, Feifei Gao, Shun Zhang
    Abstract:

    In this paper, online deep learning (DL)-based Channel estimation algorithm for doubly selective fading Channels is proposed by employing the deep neural network (DNN). With properly selected inputs, the DNN can not only exploit the features of Channel Variation from previous Channel estimates but also extract additional features from pilots and received signals. Moreover, the DNN can take the advantages of the least squares estimation to further improve the performance of Channel estimation. The DNN is first trained with simulated data in an off-line manner and then it could track the dynamic Channel in an online manner. To reduce the performance degradation from random initialization, a pre-training approach is designed to refine the initial parameters of the DNN with several epochs of training. The proposed algorithm benefits from the excellent learning and generalization capability of DL and requires no prior knowledge about the Channel statistics. Hence, it is more suitable for communication systems with modeling errors or non-stationary Channels, such as high-mobility vehicular systems, underwater acoustic systems, and molecular communication systems. The numerical results show that the proposed DL-based algorithm outperforms the existing estimator in terms of both efficiency and robustness, especially when the Channel statistics are time-varying.

  • high mobility wideband massive mimo communications doppler compensation analysis and scaling law
    arXiv: Information Theory, 2018
    Co-Authors: Wei Guo, Weile Zhang, Feifei Gao, Hai Lin
    Abstract:

    In this paper, we apply angle-domain Doppler compensation for high-mobility wideband massive multi-input multi-output (MIMO) uplink transmission. The time-varying multipath Channel is considered between high-speed terminal and static base station (BS), where multiple Doppler frequency offsets (DFOs) are associated with distinct angle of departures (AoDs). With the aid of the large-scale uniform linear array (ULA) at the transmitter, we design a beamforming network to generate multiple parallel beamforming branches, each transmitting signal pointing to one particular angle. Then, the transmitted signal in each branch will experience only one dominant DFO when passing over the time-varying Channel, which can be easily compensated before transmission starts. We theoretically analyze the Doppler spread of the equivalent uplink Channel after angle-domain Doppler compensation, which takes into account both the mainlobe and sidelobes of the transmit beam in each branch. It is seen that the Channel time-Variation can be effectively suppressed if the number of transmit antennas is sufficiently large. Interestingly, the asymptotic scaling law of Channel Variation is obtained, which shows that the Doppler spread is proportional to the maximum DFO and decreases approximately as $1/\sqrt{M}$ ($M$ is the number of transmit antennas) when $M$ is sufficiently large. Numerical results are provided to corroborate the proposed scheme.

Wei Guo - One of the best experts on this subject based on the ideXlab platform.

  • high mobility wideband massive mimo communications doppler compensation analysis and scaling laws
    IEEE Transactions on Wireless Communications, 2019
    Co-Authors: Wei Guo, Weile Zhang, Feifei Gao, Hai Lin
    Abstract:

    In this paper, we apply angle-domain Doppler compensation for high-mobility wideband massive multi-input multi-output (MIMO) uplink communications. The time-varying multipath Channel is considered between high-speed terminal and static base station (BS), where multiple Doppler frequency offsets (DFOs) are associated with distinct angle of departures (AoDs). With the aid of large-scale uniform linear array (ULA) at the transmitter, we design a beamforming network to generate multiple parallel beamforming branches, each transmitting signal pointing to one particular angle. Then, the transmitted signal in each branch will experience only one dominant DFO when passing over the time-varying Channel, which can be easily compensated before transmission starts. We theoretically analyze the Doppler spread of the equivalent uplink Channel after angle-domain Doppler compensation, which takes into account both the mainlobe and sidelobes of the transmit beam in each branch. It is seen that the Channel time-Variation can be effectively suppressed if the number of transmit antennas is sufficiently large. Interestingly, the asymptotic scaling law of Channel Variation is obtained, which shows that the Doppler spread is proportional to the maximum DFO and decreases approximately as $1/\sqrt {M}$ ( $M$ is the number of transmit antennas) when $M$ is sufficiently large. The numerical results are provided to corroborate the proposed scheme.

  • high mobility wideband massive mimo communications doppler compensation analysis and scaling law
    arXiv: Information Theory, 2018
    Co-Authors: Wei Guo, Weile Zhang, Feifei Gao, Hai Lin
    Abstract:

    In this paper, we apply angle-domain Doppler compensation for high-mobility wideband massive multi-input multi-output (MIMO) uplink transmission. The time-varying multipath Channel is considered between high-speed terminal and static base station (BS), where multiple Doppler frequency offsets (DFOs) are associated with distinct angle of departures (AoDs). With the aid of the large-scale uniform linear array (ULA) at the transmitter, we design a beamforming network to generate multiple parallel beamforming branches, each transmitting signal pointing to one particular angle. Then, the transmitted signal in each branch will experience only one dominant DFO when passing over the time-varying Channel, which can be easily compensated before transmission starts. We theoretically analyze the Doppler spread of the equivalent uplink Channel after angle-domain Doppler compensation, which takes into account both the mainlobe and sidelobes of the transmit beam in each branch. It is seen that the Channel time-Variation can be effectively suppressed if the number of transmit antennas is sufficiently large. Interestingly, the asymptotic scaling law of Channel Variation is obtained, which shows that the Doppler spread is proportional to the maximum DFO and decreases approximately as $1/\sqrt{M}$ ($M$ is the number of transmit antennas) when $M$ is sufficiently large. Numerical results are provided to corroborate the proposed scheme.

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

  • high mobility wideband massive mimo communications doppler compensation analysis and scaling laws
    IEEE Transactions on Wireless Communications, 2019
    Co-Authors: Wei Guo, Weile Zhang, Feifei Gao, Hai Lin
    Abstract:

    In this paper, we apply angle-domain Doppler compensation for high-mobility wideband massive multi-input multi-output (MIMO) uplink communications. The time-varying multipath Channel is considered between high-speed terminal and static base station (BS), where multiple Doppler frequency offsets (DFOs) are associated with distinct angle of departures (AoDs). With the aid of large-scale uniform linear array (ULA) at the transmitter, we design a beamforming network to generate multiple parallel beamforming branches, each transmitting signal pointing to one particular angle. Then, the transmitted signal in each branch will experience only one dominant DFO when passing over the time-varying Channel, which can be easily compensated before transmission starts. We theoretically analyze the Doppler spread of the equivalent uplink Channel after angle-domain Doppler compensation, which takes into account both the mainlobe and sidelobes of the transmit beam in each branch. It is seen that the Channel time-Variation can be effectively suppressed if the number of transmit antennas is sufficiently large. Interestingly, the asymptotic scaling law of Channel Variation is obtained, which shows that the Doppler spread is proportional to the maximum DFO and decreases approximately as $1/\sqrt {M}$ ( $M$ is the number of transmit antennas) when $M$ is sufficiently large. The numerical results are provided to corroborate the proposed scheme.

  • high mobility wideband massive mimo communications doppler compensation analysis and scaling law
    arXiv: Information Theory, 2018
    Co-Authors: Wei Guo, Weile Zhang, Feifei Gao, Hai Lin
    Abstract:

    In this paper, we apply angle-domain Doppler compensation for high-mobility wideband massive multi-input multi-output (MIMO) uplink transmission. The time-varying multipath Channel is considered between high-speed terminal and static base station (BS), where multiple Doppler frequency offsets (DFOs) are associated with distinct angle of departures (AoDs). With the aid of the large-scale uniform linear array (ULA) at the transmitter, we design a beamforming network to generate multiple parallel beamforming branches, each transmitting signal pointing to one particular angle. Then, the transmitted signal in each branch will experience only one dominant DFO when passing over the time-varying Channel, which can be easily compensated before transmission starts. We theoretically analyze the Doppler spread of the equivalent uplink Channel after angle-domain Doppler compensation, which takes into account both the mainlobe and sidelobes of the transmit beam in each branch. It is seen that the Channel time-Variation can be effectively suppressed if the number of transmit antennas is sufficiently large. Interestingly, the asymptotic scaling law of Channel Variation is obtained, which shows that the Doppler spread is proportional to the maximum DFO and decreases approximately as $1/\sqrt{M}$ ($M$ is the number of transmit antennas) when $M$ is sufficiently large. Numerical results are provided to corroborate the proposed scheme.

Andrea Goldsmith - One of the best experts on this subject based on the ideXlab platform.

  • effect of Channel estimation error on m qam ber performance in rayleigh fading
    IEEE Transactions on Communications, 1999
    Co-Authors: Xiaoyi Tang, Mohamedslim Alouini, Andrea Goldsmith
    Abstract:

    We determine the bit-error rate (BER) of multilevel quadrature amplitude modulation (M-QAM) in flat Rayleigh fading with imperfect Channel estimates, Despite its high spectral efficiency, M-QAM is not commonly used over fading Channels because of the Channel amplitude and phase Variation. Since the decision regions of the demodulator depend on the Channel fading, estimation error of the Channel Variation can severely degrade the demodulator performance. Among the various fading estimation techniques, pilot symbol assisted modulation (PSAM) proves to be an effective choice. We first characterize the distribution of the amplitude and phase estimates using PSAM. We then use this distribution to obtain the BER of M-QAM as a function of the PSAM and Channel parameters. By using a change of variables, our exact BER expression has a particularly simple form that involves just a few finite-range integrals. This approach can be used to compute the BER for any value of M. We compute the BER for 16-QAM and 64-QAM numerically and verify our analytical results by computer simulation. We show that for these modulations, amplitude estimation error leads to a 1-dB degradation in average signal-to-noise ratio and combined amplitude-phase estimation error leads to 2.5-dB degradation for the parameters we consider.

  • effect of Channel estimation error on m qam ber performance in rayleigh fading
    Vehicular Technology Conference, 1999
    Co-Authors: Xiaoyi Tang, Mohamedslim Alouini, Andrea Goldsmith
    Abstract:

    We determine the bit error rate (BER) of multi-level quadrature amplitude modulation (M-QAM) in flat Rayleigh fading with imperfect Channel estimates. Despite its high spectral efficiency, M-QAM is not commonly used over fading Channels because of the Channel amplitude and phase Variation. Since the decision regions of the demodulator depend on the Channel fading, the estimation error of the Channel Variation can severely degrade the demodulator performance. Among the various fading estimation techniques, pilot symbol assisted modulation (PSAM) proves to be an effective choice. We first characterize the distribution of the amplitude and phase estimates using PSAM. We then use this distribution to obtain the BER of M-QAM as a function of the PSAM and Channel parameters. By using a change of variables our exact BER expression has a particularly simple form that involves just a few finite range integrals. This approach can be used to compute BER for any value of M. We compute the BER for 16-QAM and 64-QAM numerically and verify our analytical results by computer simulation. We show that for these modulations, amplitude estimation error leads to a 1 dB degradation in E/sub b//N/sub o/ and combined amplitude-phase estimation error leads to 2.5 dB degradation for the parameters we consider.