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- Keyword
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- Channel estimation (11)
- Estimation (7)
- Phase noise (7)
- MIMO (5)
- Relays (5)
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- Signal to noise ratio (5)
- Synchronization (5)
- Receivers (4)
- Bit error rate (3)
- Cooperative systems (3)
- Cramér-Rao lower bound (CRLB) (3)
- OFDM (3)
- Signal processing algorithms (3)
- Attenuation (2)
- Cooperative communications (2)
- Detectors (2)
- Frequency estimation (2)
- Frequency synchronization (2)
- Joints (2)
- Multiple-input multiple-output (MIMO) (2)
- Satellite broadcasting (2)
- Satellites (2)
- Training (2)
- Transceivers (2)
- Wiener phase noise (2)
- Wireless communication (2)
- 5G mobile communication (1)
- Accuracy (1)
- Amplify-and-forward (1)
- Amplify-and-forward (AF) (1)
Articles 1 - 30 of 35
Full-Text Articles in Electrical and Computer Engineering
Channel Estimation And Optimal Training Design For Correlated Mimo Two-Way Relay Systems In Colored Environment, Rui Wang, Meixia Tao, Hani Mehrpouyan, Yingbo Hua
Channel Estimation And Optimal Training Design For Correlated Mimo Two-Way Relay Systems In Colored Environment, Rui Wang, Meixia Tao, Hani Mehrpouyan, Yingbo Hua
Hani Mehrpouyan
In this paper, while considering the impact of the antenna correlation and the interference from neighboring users, we analyze channel estimation and training sequence design for multi-input multi-output (MIMO) two-way relay systems. To this end, we propose to decompose the bidirectional transmission links into two phases, i.e., the multiple access (MAC) phase and the broadcast (BC) phase. By considering the Kronecker-structured channel model, we derive the optimal linear minimum mean-square-error (LMMSE) channel estimators. The corresponding training designs for the MAC phase and the BC phase are then formulated and solved to improve channel estimation accuracy. For the general scenario of …
High Rate Space-Time Codes For Millimeter-Wave Systems With Reconfigurable Antennas, Vida Vakilian, Hani Mehrpouyan, Yingbo Hua
High Rate Space-Time Codes For Millimeter-Wave Systems With Reconfigurable Antennas, Vida Vakilian, Hani Mehrpouyan, Yingbo Hua
Hani Mehrpouyan
In this paper, we propose a high-rate space-time block code (STBC) for millimeter-wave wireless communication systems that are equipped with reconfigurable multiple-input multiple-output (MIMO) antennas. We assume that each reconfigurable antenna element has the capability of forming its beam and can independently change the characteristics of its radiation pattern1. We exploit this feature of the antenna elements to construct the proposed space-time block code where each coded symbol is sent over independent beams. As a result, the received coded symbols at different receive antennas will have different power levels, a desired property that can be used in data detection. We …
Hybrid Millimeter-Wave Systems: A Novel Paradigm For Hetnets, Hani Mehrpouyan, Michail Matthaiou, Rui Wang, George K. Karagiannidis, Yingbo Hua
Hybrid Millimeter-Wave Systems: A Novel Paradigm For Hetnets, Hani Mehrpouyan, Michail Matthaiou, Rui Wang, George K. Karagiannidis, Yingbo Hua
Hani Mehrpouyan
Heterogeneous Networks (HetNets) are known to enhance the bandwidth efficiency and throughput of wireless networks by more effectively utilizing the network resources. However, the higher density of users and access points in HetNets introduces significant inter-user interference that needs to be mitigated through complex and sophisticated interference cancellation schemes. Moreover, due to significant channel attenuation and presence of hardware impairments, e.g., phase noise and amplifier nonlinearities, the vast bandwidth in the millimeter-wave band has not been fully utilized to date. In order to enable the development of multi-Gigabit per second wireless networks, we introduce a novel millimeter-wave HetNet paradigm, termed …
Bandwidth Efficient Channel Estimation For Full Duplex Communication Systems, Abbas Koohian, Hani Mehrpouyan, Mahmoud Ahmadian, Mohammad Azarbad
Bandwidth Efficient Channel Estimation For Full Duplex Communication Systems, Abbas Koohian, Hani Mehrpouyan, Mahmoud Ahmadian, Mohammad Azarbad
Hani Mehrpouyan
In this paper, the channel estimation problem in full duplex (FD) point-to-point wireless communication systems is investigated. Because of the existence of two interfering and communication channels, this problem is fundamentally different from the conventional channel estimation problems in half duplex (HD) communication systems. Here, we propose a blind channel estimator that simultaneously estimates the channel parameters of the FD system without requiring time division duplex. A major problem for blind estimators is the identifiability of the parameters. Therefore, thorough analysis is presented to determine the identifiable parameters in this estimation problem. It will be shown that a completely blind …
Channel, Phase Noise, And Frequency Offset In Ofdm Systems: Joint Estimation, Data Detection, And Hybrid Cramér-Rao Lower Bound, Omar Hazim Salim, Ali A. Nasir, Hani Mehrpouyan, Wei Xiang, Salman Durrani, Rodney A. Kennedy
Channel, Phase Noise, And Frequency Offset In Ofdm Systems: Joint Estimation, Data Detection, And Hybrid Cramér-Rao Lower Bound, Omar Hazim Salim, Ali A. Nasir, Hani Mehrpouyan, Wei Xiang, Salman Durrani, Rodney A. Kennedy
Hani Mehrpouyan
Oscillator phase noise (PHN) and carrier frequency offset (CFO) can adversely impact the performance of orthogonal frequency division multiplexing (OFDM) systems, since they can result in inter carrier interference and rotation of the signal constellation. In this paper, we propose an expectation conditional maximization (ECM) based algorithm for joint estimation of channel, PHN, and CFO in OFDM systems. We present the signal model for the estimation problem and derive the hybrid Cramér-Rao lower bound (HCRB) for the joint estimation problem. Next, we propose an iterative receiver based on an extended Kalman filter for joint data detection and PHN tracking. Numerical …
Joint Phase Noise Estimation And Data Detection In Coded Mimo Systems, Arif O. Isikman, Hani Mehrpouyan, Ali A. Nasir, Alexander G. Amat, Rodney A. Kennedy
Joint Phase Noise Estimation And Data Detection In Coded Mimo Systems, Arif O. Isikman, Hani Mehrpouyan, Ali A. Nasir, Alexander G. Amat, Rodney A. Kennedy
Hani Mehrpouyan
In this paper, the problem of joint oscillator phase noise (PHN) estimation and data detection for multi-input multi-output (MIMO) systems using bit-interleaved coded modulation (BICM) is analyzed. A new MIMO receiver that iterates between the estimator and the detector, based on the expectation-maximization (EM) framework, is proposed. It is shown that at high signal-to-noise ratios, a maximum a posteriori estimator (MAP) can be used to carry out the maximization step of the EM algorithm. Moreover, to reduce the computational complexity of the proposed EM algorithm, a soft decision-directed extended Kalman filter-smoother (EKFS) is applied instead of the MAP estimator to …
Improving Bandwidth Efficiency In E-Band Communication Systems, Hani Mehrpouyan, M. Reza Khanzadi, Michail Matthaiou, Akbar M. Sayeed, Robert Schober, Yingbo Hua
Improving Bandwidth Efficiency In E-Band Communication Systems, Hani Mehrpouyan, M. Reza Khanzadi, Michail Matthaiou, Akbar M. Sayeed, Robert Schober, Yingbo Hua
Hani Mehrpouyan
The allocation of a large amount of bandwidth by regulating bodies in the 70/80 GHz band, that is, the E-band, has opened up new potentials and challenges for providing affordable and reliable gigabit-per-second wireless point-to-point links. This article first reviews the available bandwidth and licensing regulations in the E-band. Subsequently, different propagation models (e.g., the ITU-R and Cane models) are compared against measurement results, and it is concluded that to meet specific availability requirements, E-band wireless systems may need to be designed with larger fade margins compared to microwave systems. A similar comparison is carried out between measurements …
Channel Estimation And Carrier Recovery In The Presence Of Phase Noise In Ofdm Relay Systems, Rui Wang, Hani Mehrpouyan, Meixia Tao, Yingbo Hua
Channel Estimation And Carrier Recovery In The Presence Of Phase Noise In Ofdm Relay Systems, Rui Wang, Hani Mehrpouyan, Meixia Tao, Yingbo Hua
Hani Mehrpouyan
In this paper, we analyze joint channel, carrier frequency offset (CFO), and phase noise estimation in orthogonal frequency division multiplexing (OFDM) relaying networks. To achieve this goal, a detailed transmission framework involving both training and data symbols is first presented. Next, a novel algorithm that applies the training symbols to jointly estimate the channel responses, CFO, and phase noise parameters based on the maximum a posteriori criterion is proposed. Additionally, to evaluate the performance of the proposed channel estimation and carrier recovery algorithms, we analyze the ambiguities among the estimated parameters. Based on this analysis, a new Hybrid Cramér-Rao Lower …
Enhanced List-Based Group-Wise Overloaded Receiver With Application To Satellite Reception, Zohair Abu-Shaban, Bhavani Shankar Mysore R., Hani Mehrpouyan, Björn Ottersten
Enhanced List-Based Group-Wise Overloaded Receiver With Application To Satellite Reception, Zohair Abu-Shaban, Bhavani Shankar Mysore R., Hani Mehrpouyan, Björn Ottersten
Hani Mehrpouyan
The market trends towards the use of smaller dish antennas for TV satellite receivers, as well as the growing density of broadcasting satellites in orbit require the application of robust adjacent satellite interference (ASI) cancellation algorithms at the receivers. The wider beamwidth of a small size dish and the growing number of satellites in orbit impose an overloaded scenario, i.e., a scenario where the number of transmitting satellites exceeds the number of receiving antennas. For such a scenario, we present a two stage receiver to enhance signal detection from the satellite of interest, i.e., the satellite that the dish is …
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 …
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 …
Joint Estimation Of Channel And Oscillator Phase Noise In Mimo Systems, Hani Mehrpouyan, Ali A. Nasir, Steven D. Blostein, Thomas Eriksson, George K. Karagiannidis, Tommy Svensson
Joint Estimation Of Channel And Oscillator Phase Noise In Mimo Systems, Hani Mehrpouyan, Ali A. Nasir, Steven D. Blostein, Thomas Eriksson, George K. Karagiannidis, Tommy Svensson
Hani Mehrpouyan
Oscillator phase noise limits the performance of high speed communication systems since it results in time varying channels and rotation of the signal constellation from symbol to symbol. In this paper, joint estimation of channel gains and Wiener phase noise in multi-input multi-output (MIMO) systems is analyzed. The signal model for the estimation problem is outlined in detail and new expressions for the Cramér-Rao lower bounds (CRLBs) for the multi-parameter estimation problem are derived. A data-aided least-squares (LS) estimator for jointly obtaining the channel gains and phase noise parameters is derived. Next, a decision-directed weighted least-squares (WLS) estimator is proposed, …
Timing And Carrier Synchronization With Channel Estimation In Multi-Relay Cooperative Networks, Ali A. Nasir, Hani Mehrpouyan, Steven D. Blostein, Salman Durrani, Rodney A. Kennedy
Timing And Carrier Synchronization With Channel Estimation In Multi-Relay Cooperative Networks, Ali A. Nasir, Hani Mehrpouyan, Steven D. Blostein, Salman Durrani, Rodney A. Kennedy
Hani Mehrpouyan
Multiple distributed nodes in cooperative networks generally are subject to multiple carrier frequency offsets (MCFOs) and multiple timing offsets (MTOs), which result in time varying channels and erroneous decoding. This paper seeks to develop estimation and detection algorithms that enable cooperative communications for both decode-and-forward (DF) and amplify-and-forward (AF) relaying networks in the presence of MCFOs, MTOs, and unknown channel gains. A novel transceiver structure at the relays for achieving synchronization in AF-relaying networks is proposed. New exact closed-form expressions for the Cramér-Rao lower bounds (CRLBs) for the multi-parameter estimation problem are derived. Next, two iterative algorithms based on the …
Performance Of Circular Qam Constellations With Time Varying Phase Noise, M. Assad Tariq, Hani Mehrpouyan, Tommy Svensson
Performance Of Circular Qam Constellations With Time Varying Phase Noise, M. Assad Tariq, Hani Mehrpouyan, Tommy Svensson
Hani Mehrpouyan
Time varying phase noise is a limiting factor in high-speed wireless communication systems, e.g., microwave backhaul links in cellular networks. This paper seeks to investigate the performance of circular M-ary quadrature amplitude modulations (M-QAMs) in the presence of time varying phase noise. A new approximate union bound expression for the symbol-error probability (SEP) of a specific circular M-QAM constellation is derived. Numerical results show that this expression is accurate at medium-to-high signal-to-noise ratios (SNRs) for different constellation orders, M. Next, exact closed-form expressions for the SEP of binary phase shift keying (BPSK) and quadrature phase shift keying (QPSK) …
Estimation Of Synchronization Parameters In Af Cooperative Networks, Ali A. Nasir, Hani Mehrpouyan, Steven D. Blostein, Salman Durrani, Rodney A. Kennedy
Estimation Of Synchronization Parameters In Af Cooperative Networks, Ali A. Nasir, Hani Mehrpouyan, Steven D. Blostein, Salman Durrani, Rodney A. Kennedy
Hani Mehrpouyan
In cooperative networks, multiple carrier frequency offsets (MCFOs) and multiple timing offsets (MTOs) originate due to multiple distributed nodes. In this paper, algorithms for joint estimation of these parameters and channels in amplify-and-forward (AF) relaying networks are proposed. A new training model and transceiver structure at the relays for achieving synchronization throughout the network is devised. New exact closed-form expressions for the Cramér-Rao lower bounds (CRLBs) for the multiparameter estimation problem are derived. An estimation method is proposed for jointly estimating MCFOs, MTOs, and channel gains at the destination based on space-alternating generalized expectation maximization (SAGE) and compared to a …
Time-Varying Phase Noise And Channel Estimation In Mimo Systems, Hani Mehrpouyan, Ali A. Nasir, Thomas Eriksson, Steven D. Blostein, George K. Karagiannidis, Tommy Svensson
Time-Varying Phase Noise And Channel Estimation In Mimo Systems, Hani Mehrpouyan, Ali A. Nasir, Thomas Eriksson, Steven D. Blostein, George K. Karagiannidis, Tommy Svensson
Hani Mehrpouyan
Performance of high speed communication systems is negatively affected by oscillator phase noise (PN). In this paper joint estimation of channel gains and Wiener PN in multi-input multi-output (MIMO) systems is analyzed. The signal model for the estimation problem is outlined in detail. In order to reduce overhead, a low complexity data-aided least-squares (LS) estimator for jointly obtaining the channel gains and PN parameters is derived. In order to track PN processes over a frame, a new decision-directed extended Kalman filter (EKF) is proposed. Numerical results show that the proposed LS and EKF based PN estimator performances are close …
Comments On "Timing Estimation And Resynchronization For Amplify-And-Forward Communication Systems”, Hani Mehrpouyan, Steven D. Blostein
Comments On "Timing Estimation And Resynchronization For Amplify-And-Forward Communication Systems”, Hani Mehrpouyan, Steven D. Blostein
Hani Mehrpouyan
This correspondence first shows that the Cramer-Rao lower bound (CRLB) derivations in the above paper are incorrect. In addition, contrary to the claims in the above paper, the assumptions of perfect timing offset estimation and matched-filtering at the relays affect the generality of the analytical results and cannot be justified assumption.
Bounds And Algorithms For Multiple Frequency Offset Estimation In Cooperative Networks, Hani Mehrpouyan, Steven D. Blostein
Bounds And Algorithms For Multiple Frequency Offset Estimation In Cooperative Networks, Hani Mehrpouyan, Steven D. Blostein
Hani Mehrpouyan
The distributed nature of cooperative networks may result in multiple carrier frequency offsets (CFOs), which make the channels time varying and overshadow the diversity gains promised by collaborative communications. This paper seeks to address multiple CFO estimation using training sequences in space-division multiple access (SDMA) cooperative networks. The system model and CFO estimation problem for cases of both decode-and-forward (DF) and amplify-and-forward (AF) relaying are formulated and new closed-form expressions for the Cramer-Rao lower bound (CRLB) for both protocols are derived. The CRLBs are then applied in a novel way to formulate training sequence design guidelines and determine the effect …
On Models, Bounds, And Estimation Algorithms For Time-Varying Phase Noise, M. Reza Khanzadi, Hani Mehrpouyan, Erik Alpman, Tommy Svensson, Dan Kuylenstierna, Thomas Eriksson
On Models, Bounds, And Estimation Algorithms For Time-Varying Phase Noise, M. Reza Khanzadi, Hani Mehrpouyan, Erik Alpman, Tommy Svensson, Dan Kuylenstierna, Thomas Eriksson
Hani Mehrpouyan
In this paper, a new discrete-time model of phase noise for digital communication systems, based on a comprehensive continuous-time representation of time-varying phase noise is derived and its statistical characteristics are presented. The proposed phase noise model is shown to be more accurate than the classical Wiener model. Next, using the proposed discrete-time model, the non-data-aided (NDA) and decision-directed (DD) maximum-likelihood (ML) estimators of time-varying phase noise are derived. To evaluate the performance of the proposed estimators, the Cramér-Rao lower bound (CRLB) for each estimation approach is derived and by using Monte-Carlo simulations it is shown that the mean-square error …
A New Distributed Approach For Achieving Clock Synchronization In Heterogeneous Networks, Hani Mehrpouyan, Steven D. Blostein, Tommy Svensson
A New Distributed Approach For Achieving Clock Synchronization In Heterogeneous Networks, Hani Mehrpouyan, Steven D. Blostein, Tommy Svensson
Hani Mehrpouyan
Heterogeneous networks have the potential to improve coverage, throughput, and energy efficiency of wireless networks through the use of specialized cellular structures, in particular femtocells and macrocells. However, to reduce interference between different cells, ensure smooth hand-offs from cell to cell, and achieve seamless operation the overall network needs to be synchronized. In this paper a new distributed clock synchronization scheme for heterogeneous networks is proposed that employs the clock drift information available at user-equipments (UEs) to achieve synchronization between non-interacting femtocells and macrocells. Simulation results show that the proposed scheme can significantly reduce the clock drift between macrocells and …
Optimal And Approximate Methods For Detection Of Uncoded Data With Carrier Phase Noise, Rajet Krishnan, Hani Mehrpouyan, Thomas Eriksson, Tommy Svensson
Optimal And Approximate Methods For Detection Of Uncoded Data With Carrier Phase Noise, Rajet Krishnan, Hani Mehrpouyan, Thomas Eriksson, Tommy Svensson
Hani Mehrpouyan
Previous results in the literature have shown that derivation of the optimum maximum-likelihood (ML) receiver for symbol-by-symbol (SBS) detection of an uncoded data sequence in the presence of random phase noise is an intractable problem, since it involves the computation of the conditional probability distribution function (PDF) of the phase noise process. In this paper, we seek to minimize symbol error probability (SEP), which is achieved by SBS detection of the sequence based on all received signals. We show that the ML detector for this problem can be formulated as a weighted sum of central moments of the conditional PDF …
Estimation, Training, And Effect Of Timing Offsets In Distributed Cooperative Networks, Hani Mehrpouyan, Steven D. Blostein
Estimation, Training, And Effect Of Timing Offsets In Distributed Cooperative Networks, Hani Mehrpouyan, Steven D. Blostein
Hani Mehrpouyan
Successful collaboration in cooperative networks requires accurate estimation of multiple timing offsets. When combined with signal processing algorithms, the estimated timing offsets can be applied to mitigate the resulting inter-symbol interference (ISI). This paper seeks to address timing synchronization in distributed multi-relay amplify-and-forward (AF) and decode-andforward (DF) relaying networks, where timing offset estimation using a training sequence is analyzed. First, training sequence design guidelines are presented that are shown to result in improved estimation performance. Next, two iterative estimators are derived that can determine multiple timing offsets at the destination. The proposed estimators have a considerably lower computational complexity while …
Bounds On Timing Jitter Estimation In Cooperative Networks, Hani Mehrpouyan, Steven Blostein
Bounds On Timing Jitter Estimation In Cooperative Networks, Hani Mehrpouyan, Steven Blostein
Hani Mehrpouyan
Successful collaboration and resource sharing in cooperative networks require accurate estimation of multiple timing jitters. When combined with signal processing algorithms the estimated timing jitters can be applied to mitigate the resulting inter-symbol interference (ISI) and improve performance. In this paper we seek to derive the Cramer-Rao lower bounds (CRLB) for timing jitter estimation in distributed cooperative networks. In addition to being a benchmark for judging the performance of timing jitter estimators, the CRLBs can be applied to determine the effect of the choices of training sequence and cooperative protocol on timing jitter estimation.
Synchronization In Cooperative Networks: Estimation Of Multiple Carrier Frequency Offsets, Hani Mehrpouyan, Steven Blostein
Synchronization In Cooperative Networks: Estimation Of Multiple Carrier Frequency Offsets, Hani Mehrpouyan, Steven Blostein
Hani Mehrpouyan
The distributed nature of cooperative networks may result in multiple carrier frequency offsets (CFOs), which make the channel time-varying and overshadow the performance gainspromised by collaborative communications. However, much of the analysis in the area of cooperative communications assumes perfect synchronization. This paper seeks to address frequency synchronization in cooperative communication systems, where CFO estimation using a training sequence is analyzed. The Cramer-Rao lower bound (CRLB) for various cooperative protocols is derived. In the next step, we propose two computationally efficient iterative estimators based on the MUltiple SIgnal Characterization (MUSIC) algorithm, that can estimate the CFOs from all the relays …