The Experts below are selected from a list of 9405 Experts worldwide ranked by ideXlab platform
Chengzhou Zhan - One of the best experts on this subject based on the ideXlab platform.
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dual mode low complexity codebook searching algorithm and vlsi architecture for lte lte advanced systems
IEEE Transactions on Signal Processing, 2013Co-Authors: Yihsuan Lin, Yuhao Chen, Chunyuan Chu, Chengzhou ZhanAbstract:Codebook is a useful precoding technique for bandwidth limited systems because only few bits are required to feedback channel information. Many researchers propose several codebook selection criteria for linear receivers. However, these selection criteria are very computationally intensive, and most of them are not feasible for aperiodic feedback reporting in both LTE and LTE-Advanced (LTE-A) systems. Under the limited processing hardware and feedback delay constraints, low-complexity receivers with efficient codebook selection scheme are desirable. In this work, a low-complexity codebook searching engine is proposed to support both LTE and LTE-A operations. Also, it can be operated for both aperiodic and periodic feedback reporting. The properties and mutual correlations of the LTE and LTE-A codebooks are firstly analyzed. Then, a low-complexity grouping FFT-based codebook searching algorithm is proposed, which can be shared by LTE and LTE-A systems. Since the proposed algorithm is an algorithmic transformation, there is no performance loss. The proposed schemes have significant effect of reducing the number of multiplications by 56% compared with referenced works. Finally, a dual-mode low-complexity codebook searching engine with TSMC 90 nm is implemented. The IP size is 2.2 mm2 and the Equivalent Gate count is 547.6 K. The operating frequency is 125 MHz.
Yihsuan Lin - One of the best experts on this subject based on the ideXlab platform.
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dual mode low complexity codebook searching algorithm and vlsi architecture for lte lte advanced systems
IEEE Transactions on Signal Processing, 2013Co-Authors: Yihsuan Lin, Yuhao Chen, Chunyuan Chu, Chengzhou ZhanAbstract:Codebook is a useful precoding technique for bandwidth limited systems because only few bits are required to feedback channel information. Many researchers propose several codebook selection criteria for linear receivers. However, these selection criteria are very computationally intensive, and most of them are not feasible for aperiodic feedback reporting in both LTE and LTE-Advanced (LTE-A) systems. Under the limited processing hardware and feedback delay constraints, low-complexity receivers with efficient codebook selection scheme are desirable. In this work, a low-complexity codebook searching engine is proposed to support both LTE and LTE-A operations. Also, it can be operated for both aperiodic and periodic feedback reporting. The properties and mutual correlations of the LTE and LTE-A codebooks are firstly analyzed. Then, a low-complexity grouping FFT-based codebook searching algorithm is proposed, which can be shared by LTE and LTE-A systems. Since the proposed algorithm is an algorithmic transformation, there is no performance loss. The proposed schemes have significant effect of reducing the number of multiplications by 56% compared with referenced works. Finally, a dual-mode low-complexity codebook searching engine with TSMC 90 nm is implemented. The IP size is 2.2 mm2 and the Equivalent Gate count is 547.6 K. The operating frequency is 125 MHz.
Chunyuan Chu - One of the best experts on this subject based on the ideXlab platform.
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dual mode low complexity codebook searching algorithm and vlsi architecture for lte lte advanced systems
IEEE Transactions on Signal Processing, 2013Co-Authors: Yihsuan Lin, Yuhao Chen, Chunyuan Chu, Chengzhou ZhanAbstract:Codebook is a useful precoding technique for bandwidth limited systems because only few bits are required to feedback channel information. Many researchers propose several codebook selection criteria for linear receivers. However, these selection criteria are very computationally intensive, and most of them are not feasible for aperiodic feedback reporting in both LTE and LTE-Advanced (LTE-A) systems. Under the limited processing hardware and feedback delay constraints, low-complexity receivers with efficient codebook selection scheme are desirable. In this work, a low-complexity codebook searching engine is proposed to support both LTE and LTE-A operations. Also, it can be operated for both aperiodic and periodic feedback reporting. The properties and mutual correlations of the LTE and LTE-A codebooks are firstly analyzed. Then, a low-complexity grouping FFT-based codebook searching algorithm is proposed, which can be shared by LTE and LTE-A systems. Since the proposed algorithm is an algorithmic transformation, there is no performance loss. The proposed schemes have significant effect of reducing the number of multiplications by 56% compared with referenced works. Finally, a dual-mode low-complexity codebook searching engine with TSMC 90 nm is implemented. The IP size is 2.2 mm2 and the Equivalent Gate count is 547.6 K. The operating frequency is 125 MHz.
Yuhao Chen - One of the best experts on this subject based on the ideXlab platform.
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dual mode low complexity codebook searching algorithm and vlsi architecture for lte lte advanced systems
IEEE Transactions on Signal Processing, 2013Co-Authors: Yihsuan Lin, Yuhao Chen, Chunyuan Chu, Chengzhou ZhanAbstract:Codebook is a useful precoding technique for bandwidth limited systems because only few bits are required to feedback channel information. Many researchers propose several codebook selection criteria for linear receivers. However, these selection criteria are very computationally intensive, and most of them are not feasible for aperiodic feedback reporting in both LTE and LTE-Advanced (LTE-A) systems. Under the limited processing hardware and feedback delay constraints, low-complexity receivers with efficient codebook selection scheme are desirable. In this work, a low-complexity codebook searching engine is proposed to support both LTE and LTE-A operations. Also, it can be operated for both aperiodic and periodic feedback reporting. The properties and mutual correlations of the LTE and LTE-A codebooks are firstly analyzed. Then, a low-complexity grouping FFT-based codebook searching algorithm is proposed, which can be shared by LTE and LTE-A systems. Since the proposed algorithm is an algorithmic transformation, there is no performance loss. The proposed schemes have significant effect of reducing the number of multiplications by 56% compared with referenced works. Finally, a dual-mode low-complexity codebook searching engine with TSMC 90 nm is implemented. The IP size is 2.2 mm2 and the Equivalent Gate count is 547.6 K. The operating frequency is 125 MHz.
Alexander N Korotkov - One of the best experts on this subject based on the ideXlab platform.
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operation and intrinsic error budget of a two qubit cross resonance Gate
Physical Review A, 2019Co-Authors: Vinay Tripathi, Mostafa Khezri, Alexander N KorotkovAbstract:Author(s): Tripathi, Vinay | Advisor(s): Korotkov, Alexander N. | Abstract: Due to recent developments and accessible fabrication techniques, superconducting qubitshave become one of the most popular candidates for realizing a large-scale fault-tolerantquantum computer. Currently, transmon is the most preferred type of superconductingqubits because it is less sensitivity to noise. To perform operations on the qubits, we needquantum Gates with high fidelity. One of the high-fidelity two-qubit entangling Gates usedfor superconducting qubits is the Cross-Resonance (CR) Gate. In CR Gate, two frequency-detuned qubits have a weak coupling and one of them (called control qubit) is driven by amicrowave at the frequency of the other qubit (called target). This induces Rabi oscillationsof the target qubit, whose frequency depends on the state (|0g and |1g) of the control qubit.This entangles the two qubits, thus providing a natural way to realize CNOT Gate. Inthis thesis, we study analytically, semi-analytically and numerically the operation of theCross-Resonance Gate for superconducting qubits to implement the CNOT operation. Wealso study various intrinsic errors associated with the CR Gate.Chapter 1 of this thesis gives an introduction. In Chapter 2, we discuss the Hamilitonian of the CR Gate. In Chapter 3, we first consider the ideal operation of the CR Gate, then derive the next-order analytics, and then develop a semi-analytical approach. Chapter 4 gives a description of our numerical model. Numerical results for the CNOT-Equivalent Gate duration and compensating single-qubit rotations are discussed in Chapter 5. In Chapter 6, we analyze the error budget for the CNOT-Gate intrinsic infidelity. In Chapter 7, we discuss the dependence of infidelity and CNOT duration on various parameters including detuning between control and target qubits, drive frequency, coupling between control and target qubit, smoothness of the pulse ramps, and microwave crosstalk. Chapter 8 presents conclusions.
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operation and intrinsic error budget of two qubit cross resonance Gate
arXiv: Quantum Physics, 2019Co-Authors: Vinay Tripathi, Mostafa Khezri, Alexander N KorotkovAbstract:We analyze analytically, semi-analytically, and numerically the operation of Cross-Resonance (CR) Gate for superconducting qubits (transmons). We find that a relatively simple semi-analytical method gives accurate results for the CNOT-Equivalent Gate duration and compensating single-qubit rotations. It also allows us to minimize the CNOT Gate duration over the amplitude of the applied microwave drive and find dependence on the detuning between the qubits. However, full numerical simulations are needed to calculate intrinsic fidelity of the CR Gate. We decompose numerical infidelity into contributions from various physical mechanisms, thus finding the intrinsic error budget. In particular, at small drive amplitudes the CR Gate fidelity is limited by unitary imperfections, while at large amplitudes it is limited by leakage. The Gate duration and fidelity are analyzed numerically as functions of the detuning between qubits, their coupling, drive frequency, relative duration of pulse ramps, and microwave crosstalk. Our results show that the CR Gate can provide intrinsic infidelity of less than $10^{-3}$ when a simple pulse shape is used.