The Experts below are selected from a list of 133236 Experts worldwide ranked by ideXlab platform
Babak Hossein Khalaj - One of the best experts on this subject based on the ideXlab platform.
-
Compressive Sensing-Based Pilot Design for Sparse Channel Estimation in OFDM Systems
IEEE Communications Letters, 2017Co-Authors: Roozbeh Mohammadian, Arash Amini, Babak Hossein KhalajAbstract:We consider the deterministic Pilot Design problem for sparse channel estimation in an Orthogonal Frequency Division Multiplexing (OFDM) system. Our Design is based on minimizing the coherence measure of the Fourier submatrix associated with the Pilot subcarriers. This is done by optimizing over both Pilot locations and Pilot powers. As finding such global minimizer is a combinatorial problem, we resort to a greedy Pilot allocation method. The resulting method achieves a suboptimal solution in a sequential manner and with reasonable computational complexity. Simulation results demonstrate that the proposed scheme performs similar to the existing methods with significantly lower computational complexity.
-
deterministic Pilot Design for sparse channel estimation in miso multi user ofdm systems
IEEE Transactions on Wireless Communications, 2017Co-Authors: Roozbeh Mohammadian, Arash Amini, Babak Hossein KhalajAbstract:We study the Pilot Design problem for sparse channel estimation in OFDM systems where multiple channels are estimated at a single antenna receiver. Such Design is applicable to downlink of massive-MIMO systems and also to scenarios where multiple users transmit to a base station at the same carrier frequency. In our Design, we deviate from the conventional orthogonal Pilot arrangements by assigning the same Pilot subcarriers to all transmitters. In the proposed setting, the achieved improvement in spectral efficiency (by reducing Pilot overhead) may come at the expense of a more challenging channel estimation block at the receiver. To address this challenge and distinguish between different signals that are arriving at the receiver at the same subcarrier, we propose to select Pilot subcarriers through minimizing the coherence of the associated Fourier submatrix, as well as properly assigning different Pilot values (complex numbers) to each individual transmitter. We demonstrate that if the channels are sparse enough in time domain, there are simple sparse recovery techniques to simultaneously estimate all the channels, although all transmitters share the same Pilot subcarriers. Simulation results demonstrate that the proposed Design outperforms existing methods in terms of both mean-square channel estimation error and bit error rate.
-
Deterministic Pilot Design for Sparse Channel Estimation in MISO/Multi-User OFDM Systems
IEEE Transactions on Wireless Communications, 2017Co-Authors: Roozbeh Mohammadian, Arash Amini, Babak Hossein KhalajAbstract:We study the Pilot Design problem for sparse channel estimation in OFDM systems where multiple channels are estimated at a single antenna receiver. Such Design is applicable to downlink of massive-MIMO systems and also to scenarios where multiple users transmit to a base station at the same carrier frequency. In our Design, we deviate from the conventional orthogonal Pilot arrangements by assigning the same Pilot subcarriers to all transmitters. In the proposed setting, the achieved improvement in spectral efficiency (by reducing Pilot overhead) may come at the expense of a more challenging channel estimation block at the receiver. To address this challenge and distinguish between different signals that are arriving at the receiver at the same subcarrier, we propose to select Pilot subcarriers through minimizing the coherence of the associated Fourier submatrix, as well as properly assigning different Pilot values (complex numbers) to each individual transmitter. We demonstrate that if the channels are sparse enough in time domain, there are simple sparse recovery techniques to simultaneously estimate all the channels, although all transmitters share the same Pilot subcarriers. Simulation results demonstrate that the proposed Design outperforms existing methods in terms of both mean-square channel estimation error and bit error rate.
Roozbeh Mohammadian - One of the best experts on this subject based on the ideXlab platform.
-
Compressive Sensing-Based Pilot Design for Sparse Channel Estimation in OFDM Systems
IEEE Communications Letters, 2017Co-Authors: Roozbeh Mohammadian, Arash Amini, Babak Hossein KhalajAbstract:We consider the deterministic Pilot Design problem for sparse channel estimation in an Orthogonal Frequency Division Multiplexing (OFDM) system. Our Design is based on minimizing the coherence measure of the Fourier submatrix associated with the Pilot subcarriers. This is done by optimizing over both Pilot locations and Pilot powers. As finding such global minimizer is a combinatorial problem, we resort to a greedy Pilot allocation method. The resulting method achieves a suboptimal solution in a sequential manner and with reasonable computational complexity. Simulation results demonstrate that the proposed scheme performs similar to the existing methods with significantly lower computational complexity.
-
deterministic Pilot Design for sparse channel estimation in miso multi user ofdm systems
IEEE Transactions on Wireless Communications, 2017Co-Authors: Roozbeh Mohammadian, Arash Amini, Babak Hossein KhalajAbstract:We study the Pilot Design problem for sparse channel estimation in OFDM systems where multiple channels are estimated at a single antenna receiver. Such Design is applicable to downlink of massive-MIMO systems and also to scenarios where multiple users transmit to a base station at the same carrier frequency. In our Design, we deviate from the conventional orthogonal Pilot arrangements by assigning the same Pilot subcarriers to all transmitters. In the proposed setting, the achieved improvement in spectral efficiency (by reducing Pilot overhead) may come at the expense of a more challenging channel estimation block at the receiver. To address this challenge and distinguish between different signals that are arriving at the receiver at the same subcarrier, we propose to select Pilot subcarriers through minimizing the coherence of the associated Fourier submatrix, as well as properly assigning different Pilot values (complex numbers) to each individual transmitter. We demonstrate that if the channels are sparse enough in time domain, there are simple sparse recovery techniques to simultaneously estimate all the channels, although all transmitters share the same Pilot subcarriers. Simulation results demonstrate that the proposed Design outperforms existing methods in terms of both mean-square channel estimation error and bit error rate.
-
Deterministic Pilot Design for Sparse Channel Estimation in MISO/Multi-User OFDM Systems
IEEE Transactions on Wireless Communications, 2017Co-Authors: Roozbeh Mohammadian, Arash Amini, Babak Hossein KhalajAbstract:We study the Pilot Design problem for sparse channel estimation in OFDM systems where multiple channels are estimated at a single antenna receiver. Such Design is applicable to downlink of massive-MIMO systems and also to scenarios where multiple users transmit to a base station at the same carrier frequency. In our Design, we deviate from the conventional orthogonal Pilot arrangements by assigning the same Pilot subcarriers to all transmitters. In the proposed setting, the achieved improvement in spectral efficiency (by reducing Pilot overhead) may come at the expense of a more challenging channel estimation block at the receiver. To address this challenge and distinguish between different signals that are arriving at the receiver at the same subcarrier, we propose to select Pilot subcarriers through minimizing the coherence of the associated Fourier submatrix, as well as properly assigning different Pilot values (complex numbers) to each individual transmitter. We demonstrate that if the channels are sparse enough in time domain, there are simple sparse recovery techniques to simultaneously estimate all the channels, although all transmitters share the same Pilot subcarriers. Simulation results demonstrate that the proposed Design outperforms existing methods in terms of both mean-square channel estimation error and bit error rate.
Arumugam Nallanathan - One of the best experts on this subject based on the ideXlab platform.
-
Pilot Design Schemes for Sparse Channel Estimation in OFDM Systems
IEEE Transactions on Vehicular Technology, 2015Co-Authors: Guosen Yue, Yongming Huang, Arumugam NallanathanAbstract:In this paper, we consider the Pilot Design based on the mutual incoherence property (MIP) for sparse channel estimation in orthogonal frequency-division multiplexing (OFDM) systems. With respect to the length of channel impulse response (CIR), we first derive a sufficient condition for the optimal Pilot pattern generated from the cyclic different set (CDS). Since the CDS does not exist for most practical OFDM systems, we propose three Pilot Design schemes to obtain a near-optimal Pilot pattern. The first two schemes, including stochastic sequential search (SSS) and stochastic parallel search (SPS), are based on the stochastic search. The third scheme called iterative group shrinkage (IGS) employs a tree-based searching structure and removes rows in a group instead of removing a single row at each step. We later extend our work to multiple-input–multiple-output (MIMO) systems and propose two schemes, i.e., sequential Design scheme and joint Design scheme. We also combine them to Design the multiple orthogonal Pilot patterns, i.e., using the sequential scheme for the first several transmit antennas and using the joint scheme to Design the Pilot pattern for the remaining transmit antennas. Simulation results show that the proposed SSS, SPS, and IGS converge much faster than the cross-entropy optimization and the exhaustive search and are thus more efficient. Moreover, SSS and SPS outperform IGS in terms of channel estimation performance.
-
Pilot Design for Sparse Channel Estimation in OFDM-Based Cognitive Radio Systems
IEEE Transactions on Vehicular Technology, 2014Co-Authors: Guosen Yue, Arumugam NallanathanAbstract:In this correspondence, sparse channel estimation is first introduced in orthogonal frequency-division multiplexing (OFDM)-based cognitive radio systems. Based on the results of spectrum sensing, the Pilot Design is studied by minimizing the coherence of the dictionary matrix used for sparse recovery. Then, it is formulated as an optimal column selection problem where a table is generated and the indexes of the selected columns of the table form a Pilot pattern. A novel scheme using constrained cross-entropy optimization is proposed to obtain an optimized Pilot pattern, where it is modeled as an independent Bernoulli random process. The updating rule for the probability of each active subcarrier selected as a Pilot subcarrier is derived. A projection method is proposed so that the number of Pilots during the optimization is fixed. Simulation results verify the effectiveness of the proposed scheme and show that it can achieve 11.5% improvement in spectrum efficiency with the same channel estimation performance compared with the least squares (LS) channel estimation.
Aditya K. Jagannatham - One of the best experts on this subject based on the ideXlab platform.
-
VTC-Fall - Affine Precoding Based A-Optimal Pilot Design for Channel Estimation in Single/Multicarrier (SC/MC) Block Transmission Systems
2019 IEEE 90th Vehicular Technology Conference (VTC2019-Fall), 2019Co-Authors: Manjeer Majumder, Vipul Singhal, Aditya K. JagannathamAbstract:This paper proposes a novel affine superimposed Pilot Design scheme for channel estimation in general block transmission schemes that is applicable for both single/multiple carrier (SC/MC) and zero-padded(ZP) as well as cyclic prefixed (CP) systems. The proposed approach ensures orthogonality between the Pilot and data symbols to mitigate the mutual interference between training and data in superimposed Pilot Design. The Pilot Design is based on minimization of the Bayesian Cram\'er-Rao bound (BCRB) for mean square error (MSE) of the channel estimation error subject to total Pilot power constraint. The proposed technique also incorporates the channel correlation matrix for improved estimation. The optimal Pilot placement is formulated as an A- Optimal Design-based semi-definite program (SDP) that can be solved efficiently. Simulation results are presented for single carrier and multi carrier zero padded and cyclic prefixed systems to demonstrate the performance of the proposed scheme.
-
NCC - Optimal Pilot Design for channel estimation in single/multicarrier block transmission systems
2017 Twenty-third National Conference on Communications (NCC), 2017Co-Authors: Manjeer Majumder, Ankit Kudeshia, Aditya K. JagannathamAbstract:This paper proposes a novel approach for optimal Pilot sequence Design for channel estimation in single carrier (SC) and multi carrier (MC) block transmission systems over frequency selective channels. The training Design is based on minimizing the Bayesian Cramer-Rao bound (BCRB) for mean square error (MSE) of channel estimation which also employs the prior knowledge of the channel in conjunction with the receiver noise covariance subject to a total transmit power constraint. The proposed scheme derives the optimal Pilot sequence which is applicable to all four block transmission systems i.e. single carrier zero padding (SC-ZP), multi-carrier zero padding (MC-ZP), single carrier cyclic prefix (SC-CP) and multi-carrier cyclic prefix (MC-CP) systems. Thus, the proposed framework and results derived are general with wide applicability. Simulation results are presented to show the improved performance of the proposed Pilot Design scheme in comparison to a conventional Pilot Design, in terms of both the mean square error (MSE) and bit error rate (BER).
Arash Amini - One of the best experts on this subject based on the ideXlab platform.
-
Compressive Sensing-Based Pilot Design for Sparse Channel Estimation in OFDM Systems
IEEE Communications Letters, 2017Co-Authors: Roozbeh Mohammadian, Arash Amini, Babak Hossein KhalajAbstract:We consider the deterministic Pilot Design problem for sparse channel estimation in an Orthogonal Frequency Division Multiplexing (OFDM) system. Our Design is based on minimizing the coherence measure of the Fourier submatrix associated with the Pilot subcarriers. This is done by optimizing over both Pilot locations and Pilot powers. As finding such global minimizer is a combinatorial problem, we resort to a greedy Pilot allocation method. The resulting method achieves a suboptimal solution in a sequential manner and with reasonable computational complexity. Simulation results demonstrate that the proposed scheme performs similar to the existing methods with significantly lower computational complexity.
-
deterministic Pilot Design for sparse channel estimation in miso multi user ofdm systems
IEEE Transactions on Wireless Communications, 2017Co-Authors: Roozbeh Mohammadian, Arash Amini, Babak Hossein KhalajAbstract:We study the Pilot Design problem for sparse channel estimation in OFDM systems where multiple channels are estimated at a single antenna receiver. Such Design is applicable to downlink of massive-MIMO systems and also to scenarios where multiple users transmit to a base station at the same carrier frequency. In our Design, we deviate from the conventional orthogonal Pilot arrangements by assigning the same Pilot subcarriers to all transmitters. In the proposed setting, the achieved improvement in spectral efficiency (by reducing Pilot overhead) may come at the expense of a more challenging channel estimation block at the receiver. To address this challenge and distinguish between different signals that are arriving at the receiver at the same subcarrier, we propose to select Pilot subcarriers through minimizing the coherence of the associated Fourier submatrix, as well as properly assigning different Pilot values (complex numbers) to each individual transmitter. We demonstrate that if the channels are sparse enough in time domain, there are simple sparse recovery techniques to simultaneously estimate all the channels, although all transmitters share the same Pilot subcarriers. Simulation results demonstrate that the proposed Design outperforms existing methods in terms of both mean-square channel estimation error and bit error rate.
-
Deterministic Pilot Design for Sparse Channel Estimation in MISO/Multi-User OFDM Systems
IEEE Transactions on Wireless Communications, 2017Co-Authors: Roozbeh Mohammadian, Arash Amini, Babak Hossein KhalajAbstract:We study the Pilot Design problem for sparse channel estimation in OFDM systems where multiple channels are estimated at a single antenna receiver. Such Design is applicable to downlink of massive-MIMO systems and also to scenarios where multiple users transmit to a base station at the same carrier frequency. In our Design, we deviate from the conventional orthogonal Pilot arrangements by assigning the same Pilot subcarriers to all transmitters. In the proposed setting, the achieved improvement in spectral efficiency (by reducing Pilot overhead) may come at the expense of a more challenging channel estimation block at the receiver. To address this challenge and distinguish between different signals that are arriving at the receiver at the same subcarrier, we propose to select Pilot subcarriers through minimizing the coherence of the associated Fourier submatrix, as well as properly assigning different Pilot values (complex numbers) to each individual transmitter. We demonstrate that if the channels are sparse enough in time domain, there are simple sparse recovery techniques to simultaneously estimate all the channels, although all transmitters share the same Pilot subcarriers. Simulation results demonstrate that the proposed Design outperforms existing methods in terms of both mean-square channel estimation error and bit error rate.
