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Articles 1 - 9 of 9
Full-Text Articles in Engineering
Optimal Training Sequences For Joint Timing Synchronization And Channel Estimation In Distributed Communication Networks, Ali A. Nasir, Hani Mehrpouyan, Salman Durrani, Steven D. Blostein, Rodney A. Kennedy, Björn Ottersten
Optimal Training Sequences For Joint Timing Synchronization And Channel Estimation In Distributed Communication Networks, Ali A. Nasir, Hani Mehrpouyan, Salman Durrani, Steven D. Blostein, Rodney A. Kennedy, Björn Ottersten
Hani Mehrpouyan
For distributed multi-user and multi-relay cooperative networks, the received signal may be affected by multiple timing offsets (MTOs) and multiple channels that need to be jointly estimated for successful decoding at the receiver. This paper addresses the design of optimal training sequences for efficient estimation of MTOs and multiple channel parameters. A new hybrid Cramér-Rao lower bound (HCRB) for joint estimation of MTOs and channels is derived. Subsequently, by minimizing the derived HCRB as a function of training sequences, three training sequence design guidelines are derived and according to these guidelines, two training sequences are proposed. In order to show …
Transceiver Design For Distributed Stbc Based Af Cooperative Networks In The Presence Of Timing And Frequency Offsets, Ali A. Nasir, Hani Mehrpouyan, Salman Durrani, Steven D. Blostein, Rodney A. Kennedy, Björn Ottersten
Transceiver Design For Distributed Stbc Based Af Cooperative Networks In The Presence Of Timing And Frequency Offsets, Ali A. Nasir, Hani Mehrpouyan, Salman Durrani, Steven D. Blostein, Rodney A. Kennedy, Björn Ottersten
Hani Mehrpouyan
In multi-relay cooperative systems, the signal at the destination is affected by impairments such as multiple channel gains, multiple timing offsets (MTOs), and multiple carrier frequency offsets (MCFOs). In this paper we account for all these impairments and propose a new transceiver structure at the relays and a novel receiver design at the destination in distributed space-time block code (DSTBC) based amplify-and-forward (AF) cooperative networks. The Cramér-Rao lower bounds and a least squares (LS) estimator for the multi-parameter estimation problem are derived. In order to significantly reduce the receiver complexity at the destination, a differential evolution (DE) based …
Phase Noise In Mimo Systems: Bayesian Cramér-Rao Bounds And Soft-Input Estimation, Ali A. Nasir, Hani Mehrpouyan, Robert Schober, Yingbo Hua
Phase Noise In Mimo Systems: Bayesian Cramér-Rao Bounds And Soft-Input Estimation, Ali A. Nasir, Hani Mehrpouyan, Robert Schober, Yingbo Hua
Hani Mehrpouyan
This paper addresses the problem of estimating time varying phase noise caused by imperfect oscillators in multi-input multi-output (MIMO) systems. The estimation problem is parameterized in detail and based on an equivalent signal model its dimensionality is reduced to minimize the overhead associated with phase noise estimation. New exact and closed-form expressions for the Bayesian Cram´er-Rao lower bounds (BCRLBs) and soft-input maximum a posteriori (MAP) estimators for online, i.e., filtering, and offline, i.e., smoothing, estimation of phase noise over the length of a frame are derived. Simulations demonstrate that the proposed MAP estimators’ mean-square error (MSE) performances are …
Net Energy Metering For Residences: Impacts Of Tariff Design, John Gardner
Net Energy Metering For Residences: Impacts Of Tariff Design, John Gardner
John Gardner
No abstract provided.
Simultaneous Estimation Of Multi-Relay Mimo Channels, Hani Mehrpouyan, Steven D. Blostein, Björn Ottersten
Simultaneous Estimation Of Multi-Relay Mimo Channels, Hani Mehrpouyan, Steven D. Blostein, Björn Ottersten
Hani Mehrpouyan
This paper addresses training-based channel estimation in distributed amplify-and-forward (AF) multi-input multi-output (MIMO) multi-relay networks. To reduce channel estimation overhead and delay, a training algorithm that allows for simultaneous estimation of the entire MIMO cooperative network’s channel parameters at the destination node is proposed. The exact Cramér-Rao lower bound (CRLB) for the problem is presented in closed-form. Channel estimators that are capable of estimating the overall source-relay-destination channel parameters at the destination are also derived. Numerical results show that while reducing delay, the proposed channel estimators are close to the derived CRLB over a wide range of signal-to-noise ratio values …
New Expression For The Functional Transformation Of The Vector Cramér-Rao Lower Bound, Ali A. Nasir, Hani Mehrpouyan, Rodney A. Kennedy
New Expression For The Functional Transformation Of The Vector Cramér-Rao Lower Bound, Ali A. Nasir, Hani Mehrpouyan, Rodney A. Kennedy
Hani Mehrpouyan
Assume that it is desired to estimate α = f(θ), where f(·) is an r-dimensional function. This paper derives the general expression for the functional transformation of the vector Cramér-Rao lower bound (CRLB). The derived bound is a tight lower bound on the estimation of uncoupled parameters, i.e., parameters that can be estimated separately. Unlike previous results in the literature, this new expression is not dependent on the inverse of the Fisher’s information matrix (FIM) of the untransformed parameters, θ. Thus, it can be applied to scenarios where the FIM for θ is ill-conditioned or singular. …
Phase Noise And Carrier Frequency Offset In Ofdm Systems: Joint Estimation And Hybrid Cramér-Rao Lower Bound, Omar Hazim Salim, Ali A. Nasir, Hani Mehrpouyan, Wei Xiang
Phase Noise And Carrier Frequency Offset In Ofdm Systems: Joint Estimation And Hybrid Cramér-Rao Lower Bound, Omar Hazim Salim, Ali A. Nasir, Hani Mehrpouyan, Wei Xiang
Hani Mehrpouyan
In this paper, a new iterative pilot-aided algorithm based on expectation conditional maximization (ECM) for joint estimation of Wiener phase noise (PHN) and carrier frequency offset (CFO) in orthogonal frequency division multiplexing (OFDM) systems is proposed. Next, a new expression for the hybrid Cramér-Rao lower bound (HCRB) for joint estimation of PHN and CFO in OFDM systems is derived. Numerical results show that the proposed estimator outperforms existing algorithms in terms of mean square error while performing close to the derived HCRB at moderate PHN variances. Moreover, the proposed estimator is found to be computationally more efficient than existing algorithms …
Dstbc Based Df Cooperative Networks In The Presence Of Timing And Frequency Offsets, Ali A. Nasir, Hani Mehrpouyan, Salman Durrani, Steven D. Blostein, Rodney A. Kennedy, Björn Ottersten
Dstbc Based Df Cooperative Networks In The Presence Of Timing And Frequency Offsets, Ali A. Nasir, Hani Mehrpouyan, Salman Durrani, Steven D. Blostein, Rodney A. Kennedy, Björn Ottersten
Hani Mehrpouyan
In decode-and-forward (DF) relaying networks, the received signal at the destination may be affected by multiple impairments such as multiple channel gains, multiple timing offsets (MTOs), and multiple carrier frequency offsets (MCFOs). This paper proposes novel optimal and sub-optimal minimum mean-square error (MMSE) receiver designs at the destination node to detect the signal in the presence of these impairments. Distributed space-time block codes (DSTBCs) are used at the relays to achieve spatial diversity. The proposed sub-optimal receiver uses the estimated values of multiple channel gains, MTOs, and MCFOs, while the optimal receiver assumes perfect knowledge of these impairments at the …
Overloaded Satellite Receiver Using Sic With Hybrid Beamforming And Ml Detection, Zohair Abu-Shaban, Hani Mehrpouyan, Joel Grotz, Björn Ottersten
Overloaded Satellite Receiver Using Sic With Hybrid Beamforming And Ml Detection, Zohair Abu-Shaban, Hani Mehrpouyan, Joel Grotz, Björn Ottersten
Hani Mehrpouyan
In this paper, a new receiver structure that is intended to detect the signals from multiple adjacent satellites in the presence of other interfering satellites is proposed. We tackle the worst case interference conditions, i.e., it is assumed that uncoded signals that fully overlap in frequency arrive at a multiple-element small-size parabolic antenna in a spatially correlated noise environment. The proposed successive interference cancellation (SIC) receiver, denoted by SIC Hy/ML, employs hybrid beamforming and disjoint maximum likelihood (ML) detection. Depending on the individual signals spatial position, the proposed SIC Hy/ML scheme takes advantage of two types of beamformers: a …