Miso

14,000,000 Leading Edge Experts on the ideXlab platform

Scan Science and Technology

Contact Leading Edge Experts & Companies

Scan Science and Technology

Contact Leading Edge Experts & Companies

The Experts below are selected from a list of 17898 Experts worldwide ranked by ideXlab platform

Dirk Slock - One of the best experts on this subject based on the ideXlab platform.

  • A Refined Analysis of the Gap Between Expected Rate for Partial Csit and the Massive Mimo Rate Limit
    2018 IEEE International Conference on Acoustics Speech and Signal Processing (ICASSP), 2018
    Co-Authors: Kalyana Gopala, Dirk Slock
    Abstract:

    Optimal BeamFormers (BFs) that maximize the Weighted Sum Rate (WSR) for a Multiple-Input Multiple-Output (MIMO) interference broadcast channel (IBC) remains an important research area. Under practical scenarios, the problem is compounded by the fact that only partial channel state information at the transmitter (CSIT) is available. Hence, a typical choice of the optimization metric is the Expected Weighted Sum Rate (EWSR). However, the presence of the expectation operator makes the optimization a daunting task. On the other hand, for the particular, but significant, special case of massive MIMO (MaMIMO), the EWSR converges to Expected Signal covariance Expected Interference covariance based WSR (ESEI-WSR) and this metric is more amenable to optimization. Recently, [1] considered a multi-user Multiple-Input Single-Output (Miso) scenario and proposed approximating the EWSR by ESEI-WSR. They then derived a constant bound for this approximation. This paper performs a refined analysis of the gap between EWSR and ESEI - WSR criteria for finite antenna dimensions.

  • MIMO IBC beamforming with combined channel estimate and covariance CSIT
    2017 IEEE International Symposium on Information Theory (ISIT), 2017
    Co-Authors: Wassim Tabikh, Dirk Slock, Yi Yuan-wu
    Abstract:

    This work deals with beamforming for the MIMO Interfering Broadcast Channel (IBC), i.e. the Multi-Input MultiOutput (MIMO) Multi-User Multi-Cell downlink (DL). The novel beamformers are here optimized for the Expected Weighted Sum Rate (EWSR) for the case of Partial Channel State Information at the Transmitters (CSIT). Gaussian (Posterior) partial CSIT can optimally combine channel estimate and channel covariance information. We introduce the first large system analysis for optimized beamformers with partial CSIT, here for the Massive Miso (MaMiso) case. In the case of Gaussian partial CSIT, the beamformers only depend on the means and covariances of the channels. The large system analysis furthermore allows to predict the EWSR performance on the basis of the channel statistics only.

  • Relay aided coordinated beamforming and interference neutralization
    2017 Information Theory and Applications Workshop (ITA), 2017
    Co-Authors: Wassim Tabikh, Dirk Slock, Yi Yuan-wu
    Abstract:

    We consider the Multi-Input Single Output (Miso) Interfering Broadcast Channel (IBC), in other words the multi-user (MU) multi-cell half duplex downlink in a cellular or heterogeneous network, aided by a full duplex MIMO relay. The Degrees of Freedom (DoF) are analyzed for joint coordinated beamforming by the base stations and interference neutralization by the relay. Also Weighted Sum Rate Maximization at finite SNR is developed. The main concern however for interference neutralization is channel state information (CSI) at the relay, which does not observe the direct user links. Various solutions are explored.

  • From MU massive Miso to pathwise MU massive MIMO
    2014 IEEE 15th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC), 2014
    Co-Authors: Yohan Lejosne, Dirk Slock, Manijeh Bashar, Yi Yuan-wu
    Abstract:

    The Interfering Broadcast Channel (IBC) applies to the downlink of cellular and heterogenous networks, which are limited by multi-user (MU) interference. The interference alignment (IA) concept has shown that interference does not need to be inevitable. In particular spatial IA in MIMO IBC allows for low latency. However, IA requires perfect and typically global Channel State Information at the Transmitter(s) (CSIT), whose acquisition does not scale with network size. Hence, designs that are optimal in terms of Degrees of Freedom (DoF) may not be so in terms of more relevant net DoF, accounting for CSI acquistion or at finite SNR. Also, the design of transmitters (Txs) and receivers (Rxs) is coupled and hence needs to be centralized or duplicated. Here we propose to take advantage of Massive MIMO simplifications, esp. for mmWave, by considering (multi-)path CSIT for crosslinks, which can be obtained without feedback. We consider a hierarchical cross/direct link beamformer design, maximizing Weighted Sum Rate (WSR) with partial CSIT at finite SNR, requiring on local CSIT. We also point out the use of receive antennas in genuine MU Massive MIMO.

  • Ergodic interference alignment for the SIMO/MIMO interference channel
    2014 IEEE International Conference on Acoustics Speech and Signal Processing (ICASSP), 2014
    Co-Authors: Yohan Lejosne, Dirk Slock, Yi Yuan-wu
    Abstract:

    Ergodic interference alignment (IA) is a simple yet powerful tool that not only achieves the optimal K/2 degrees of freedom (DoF) of the K-user single-input single-output (SISO) interference channel (IC), but also allows each user to achieve at least half of its interference-free capacity at any SNR. By considering more general message sets, Nazer et al. also covered the Miso case. In this paper, we consider first the SIMO interference channel and extend ergodic IA techniques to this setting with Nr receive antennas. Our scheme achieves KNr/(Nr + 1), which is the DoF yielded by (standard) IA and is also the DoF of the channel when K > Nr. Moreover, this technique exhibits spatial scale invariance. By combining the existing Miso and the new SIMO results, we can also cover MIMO with Nt transmit antennas for the cases where either Nt/Nr or Nr/Nt is an integer R, yielding DoF =3D min(Nt, Nr)KR/(R + 1) which is optimal for K > R.

Yi Yuan-wu - One of the best experts on this subject based on the ideXlab platform.

  • MIMO IBC beamforming with combined channel estimate and covariance CSIT
    2017 IEEE International Symposium on Information Theory (ISIT), 2017
    Co-Authors: Wassim Tabikh, Dirk Slock, Yi Yuan-wu
    Abstract:

    This work deals with beamforming for the MIMO Interfering Broadcast Channel (IBC), i.e. the Multi-Input MultiOutput (MIMO) Multi-User Multi-Cell downlink (DL). The novel beamformers are here optimized for the Expected Weighted Sum Rate (EWSR) for the case of Partial Channel State Information at the Transmitters (CSIT). Gaussian (Posterior) partial CSIT can optimally combine channel estimate and channel covariance information. We introduce the first large system analysis for optimized beamformers with partial CSIT, here for the Massive Miso (MaMiso) case. In the case of Gaussian partial CSIT, the beamformers only depend on the means and covariances of the channels. The large system analysis furthermore allows to predict the EWSR performance on the basis of the channel statistics only.

  • Relay aided coordinated beamforming and interference neutralization
    2017 Information Theory and Applications Workshop (ITA), 2017
    Co-Authors: Wassim Tabikh, Dirk Slock, Yi Yuan-wu
    Abstract:

    We consider the Multi-Input Single Output (Miso) Interfering Broadcast Channel (IBC), in other words the multi-user (MU) multi-cell half duplex downlink in a cellular or heterogeneous network, aided by a full duplex MIMO relay. The Degrees of Freedom (DoF) are analyzed for joint coordinated beamforming by the base stations and interference neutralization by the relay. Also Weighted Sum Rate Maximization at finite SNR is developed. The main concern however for interference neutralization is channel state information (CSI) at the relay, which does not observe the direct user links. Various solutions are explored.

  • From MU massive Miso to pathwise MU massive MIMO
    2014 IEEE 15th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC), 2014
    Co-Authors: Yohan Lejosne, Dirk Slock, Manijeh Bashar, Yi Yuan-wu
    Abstract:

    The Interfering Broadcast Channel (IBC) applies to the downlink of cellular and heterogenous networks, which are limited by multi-user (MU) interference. The interference alignment (IA) concept has shown that interference does not need to be inevitable. In particular spatial IA in MIMO IBC allows for low latency. However, IA requires perfect and typically global Channel State Information at the Transmitter(s) (CSIT), whose acquisition does not scale with network size. Hence, designs that are optimal in terms of Degrees of Freedom (DoF) may not be so in terms of more relevant net DoF, accounting for CSI acquistion or at finite SNR. Also, the design of transmitters (Txs) and receivers (Rxs) is coupled and hence needs to be centralized or duplicated. Here we propose to take advantage of Massive MIMO simplifications, esp. for mmWave, by considering (multi-)path CSIT for crosslinks, which can be obtained without feedback. We consider a hierarchical cross/direct link beamformer design, maximizing Weighted Sum Rate (WSR) with partial CSIT at finite SNR, requiring on local CSIT. We also point out the use of receive antennas in genuine MU Massive MIMO.

  • Ergodic interference alignment for the SIMO/MIMO interference channel
    2014 IEEE International Conference on Acoustics Speech and Signal Processing (ICASSP), 2014
    Co-Authors: Yohan Lejosne, Dirk Slock, Yi Yuan-wu
    Abstract:

    Ergodic interference alignment (IA) is a simple yet powerful tool that not only achieves the optimal K/2 degrees of freedom (DoF) of the K-user single-input single-output (SISO) interference channel (IC), but also allows each user to achieve at least half of its interference-free capacity at any SNR. By considering more general message sets, Nazer et al. also covered the Miso case. In this paper, we consider first the SIMO interference channel and extend ergodic IA techniques to this setting with Nr receive antennas. Our scheme achieves KNr/(Nr + 1), which is the DoF yielded by (standard) IA and is also the DoF of the channel when K > Nr. Moreover, this technique exhibits spatial scale invariance. By combining the existing Miso and the new SIMO results, we can also cover MIMO with Nt transmit antennas for the cases where either Nt/Nr or Nr/Nt is an integer R, yielding DoF =3D min(Nt, Nr)KR/(R + 1) which is optimal for K > R.

  • Space time interference alignment scheme for the MIMO BC and IC with delayed CSIT and finite coherence time
    2013 IEEE International Conference on Acoustics Speech and Signal Processing, 2013
    Co-Authors: Yohan Lejosne, Dirk Slock, Yi Yuan-wu
    Abstract:

    Most techniques designed for the the multi-input multiple-output (MIMO) Broadcast Channel (BC) andMIMO Interference Channel (IC) require accurate current and instantaneous channel state information at the transmitter (CSIT). This is not a realistic assumption because of feedback delay. A novel approach by Lee and Heath, space-time interference alignment (STIA), proves that in the underdetermined (overloaded) multi-input single-output (Miso) BC with Nt transmit antennas and K = Nt + 1 users Nt (sum) Degrees of Freedom (DoF) are achievable if the feedback delay is not too big, thus disproving the conjecture that any delay in the feedback necessarily causes a DoF loss. However the feedback delay needs to remain less or equal to Tc over Nt+1, where Tc is the coherence time. We consider the MIMO BC and show that the use of multi-antenna receivers allows to achieve full (sum) DoF with bigger feedback delay, up to equation. We also extend this result to the MIMO IC.

Minjie Liu - One of the best experts on this subject based on the ideXlab platform.

  • Performance analysis of time-reversal based precoding schemes in Miso-OFDM systems
    IEEE Vehicular Technology Conference, 2015
    Co-Authors: Mohamad Maaz, Philippe Mary, Maryline Helard, Minjie Liu
    Abstract:

    Time-Reversal (TR) precoding schemes are regarded as promising candidates for robust and energy efficient wireless systems. These schemes are characterized by their low computational complexity at the receiver side. In multipath Rayleigh fading channel, this paper presents analytical expressions of the average bit error rate (BER) of TR technique and the Equal Gain Transmission (EGT) scheme in Miso-OFDM systems. It further provides simple and tight upper bounds on the ergodic capacity of these schemes. Hence, these theoretical analyses might be very useful to avoid lengthy simulations. It also provides an interesting conclusion: for large number of transmit antennas, i.e. in Massive MIMO, TR technique outperforms the EGT scheme and its performance approaches that of Maximum Ratio Transmission (MRT) scheme. Hence, it confirms the applicability of TR scheme in the future Massive MIMO systems. Results with LTE-A system parameters are provided in order to corroborate our analysis.

Mohamad Maaz - One of the best experts on this subject based on the ideXlab platform.

  • Performance Analysis of Time-Reversal Based Precoding Schemes in Miso-OFDM Systems
    2015
    Co-Authors: Mohamad Maaz, Maryline Helard, Philippe Mary
    Abstract:

    Time-Reversal (TR) precoding schemes are regarded as promising candidates for robust and energy-efficient wireless systems. These schemes are characterized by their low computa- tional complexity at the receiver side. In this paper, we present novel analytical expressions of the average bit error rate (BER) of TR technique and the Equal Gain Transmission (EGT) scheme in Miso-OFDM systems. We further provide simple and tight upper bounds on the ergodic capacity of these schemes. Hence, these theoretical analyses might be very useful to avoid lengthy simulations. This paper also provides an interesting conclusion: For large number of transmit antennas, i.e. in Massive MIMO, TR technique outperforms the EGT scheme and its performance approaches that of Maximum Ratio Transmission (MRT) scheme. Hence, it confirms the applicability of TR scheme in the future Massive MIMO systems. Simulation results with LTE-A system parameters are provided in order to corroborate our analysis.

  • Performance analysis of time-reversal based precoding schemes in Miso-OFDM systems
    IEEE Vehicular Technology Conference, 2015
    Co-Authors: Mohamad Maaz, Philippe Mary, Maryline Helard, Minjie Liu
    Abstract:

    Time-Reversal (TR) precoding schemes are regarded as promising candidates for robust and energy efficient wireless systems. These schemes are characterized by their low computational complexity at the receiver side. In multipath Rayleigh fading channel, this paper presents analytical expressions of the average bit error rate (BER) of TR technique and the Equal Gain Transmission (EGT) scheme in Miso-OFDM systems. It further provides simple and tight upper bounds on the ergodic capacity of these schemes. Hence, these theoretical analyses might be very useful to avoid lengthy simulations. It also provides an interesting conclusion: for large number of transmit antennas, i.e. in Massive MIMO, TR technique outperforms the EGT scheme and its performance approaches that of Maximum Ratio Transmission (MRT) scheme. Hence, it confirms the applicability of TR scheme in the future Massive MIMO systems. Results with LTE-A system parameters are provided in order to corroborate our analysis.

Yohan Lejosne - One of the best experts on this subject based on the ideXlab platform.

  • From MU massive Miso to pathwise MU massive MIMO
    2014 IEEE 15th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC), 2014
    Co-Authors: Yohan Lejosne, Dirk Slock, Manijeh Bashar, Yi Yuan-wu
    Abstract:

    The Interfering Broadcast Channel (IBC) applies to the downlink of cellular and heterogenous networks, which are limited by multi-user (MU) interference. The interference alignment (IA) concept has shown that interference does not need to be inevitable. In particular spatial IA in MIMO IBC allows for low latency. However, IA requires perfect and typically global Channel State Information at the Transmitter(s) (CSIT), whose acquisition does not scale with network size. Hence, designs that are optimal in terms of Degrees of Freedom (DoF) may not be so in terms of more relevant net DoF, accounting for CSI acquistion or at finite SNR. Also, the design of transmitters (Txs) and receivers (Rxs) is coupled and hence needs to be centralized or duplicated. Here we propose to take advantage of Massive MIMO simplifications, esp. for mmWave, by considering (multi-)path CSIT for crosslinks, which can be obtained without feedback. We consider a hierarchical cross/direct link beamformer design, maximizing Weighted Sum Rate (WSR) with partial CSIT at finite SNR, requiring on local CSIT. We also point out the use of receive antennas in genuine MU Massive MIMO.

  • Ergodic interference alignment for the SIMO/MIMO interference channel
    2014 IEEE International Conference on Acoustics Speech and Signal Processing (ICASSP), 2014
    Co-Authors: Yohan Lejosne, Dirk Slock, Yi Yuan-wu
    Abstract:

    Ergodic interference alignment (IA) is a simple yet powerful tool that not only achieves the optimal K/2 degrees of freedom (DoF) of the K-user single-input single-output (SISO) interference channel (IC), but also allows each user to achieve at least half of its interference-free capacity at any SNR. By considering more general message sets, Nazer et al. also covered the Miso case. In this paper, we consider first the SIMO interference channel and extend ergodic IA techniques to this setting with Nr receive antennas. Our scheme achieves KNr/(Nr + 1), which is the DoF yielded by (standard) IA and is also the DoF of the channel when K > Nr. Moreover, this technique exhibits spatial scale invariance. By combining the existing Miso and the new SIMO results, we can also cover MIMO with Nt transmit antennas for the cases where either Nt/Nr or Nr/Nt is an integer R, yielding DoF =3D min(Nt, Nr)KR/(R + 1) which is optimal for K > R.

  • Space time interference alignment scheme for the MIMO BC and IC with delayed CSIT and finite coherence time
    2013 IEEE International Conference on Acoustics Speech and Signal Processing, 2013
    Co-Authors: Yohan Lejosne, Dirk Slock, Yi Yuan-wu
    Abstract:

    Most techniques designed for the the multi-input multiple-output (MIMO) Broadcast Channel (BC) andMIMO Interference Channel (IC) require accurate current and instantaneous channel state information at the transmitter (CSIT). This is not a realistic assumption because of feedback delay. A novel approach by Lee and Heath, space-time interference alignment (STIA), proves that in the underdetermined (overloaded) multi-input single-output (Miso) BC with Nt transmit antennas and K = Nt + 1 users Nt (sum) Degrees of Freedom (DoF) are achievable if the feedback delay is not too big, thus disproving the conjecture that any delay in the feedback necessarily causes a DoF loss. However the feedback delay needs to remain less or equal to Tc over Nt+1, where Tc is the coherence time. We consider the MIMO BC and show that the use of multi-antenna receivers allows to achieve full (sum) DoF with bigger feedback delay, up to equation. We also extend this result to the MIMO IC.

  • User Selection on MIMO BC
    European Signal Processing Conference (EUSIPCO), 2012
    Co-Authors: Yohan Lejosne, Dirk Slock, Yi Yuan
    Abstract:

    It is well-known that user selection not only leads to multi- user diversity but also to decreased suboptimality of simple beamforming (BF) techniques compared to optimal Dirty Pa- per Coding (DPC) approaches in theBroadcastChannel (BC), otherwise called the multi-user (MU) downlink, in a cell with a base station and mobile terminals equipped with multiple antennas (MU-MIMO). User selection by exhaustive search can be simplified to greedy approaches, in which one user gets added at a time. In this paper, we review an approxi- mate criterion for Miso BF-style selection. For a sufficient amount of users, multiple receive antennas do not lead to in- creased spatial multiplexing, but we indicate how they affect the high SNR rate offset. The resulting added diversity can be exploited at the cost of more involved user selection and transceiver design. We thus propose a novel receiver design for BF-styleMU-MIMO stream selection.

  • User selection in the MIMO BC
    2012 Proceedings of the 20th European Signal Processing Conference (EUSIPCO), 2012
    Co-Authors: Yohan Lejosne, Dirk Slock, Yi Yuan-wu
    Abstract:

    It is well-known that user selection not only leads to multiuser diversity but also to decreased suboptimality of simple beamforming (BF) techniques compared to optimal Dirty Paper Coding (DPC) approaches in the Broadcast Channel (BC), otherwise called the multi-user (MU) downlink, in a cell with a base station and mobile terminals equipped with multiple antennas (MU-MIMO). User selection by exhaustive search can be simplified to greedy approaches, in which one user gets added at a time. In this paper, we review an approximate criterion for Miso BF-style selection. For a sufficient amount of users, multiple receive antennas do not lead to increased spatial multiplexing, but we indicate how they affect the high SNR rate offset. The resulting added diversity can be exploited at the cost of more involved user selection and transceiver design. We thus propose a novel receiver design for BF-style MU-MIMO stream selection.

Miso - 15 days free trial to Access Experts & Abstracts