Yuan-Pei Lin - Academia.edu (original) (raw)

Papers by Yuan-Pei Lin

2008 IEEE International Conference on Acoustics, Speech and Signal Processing, 2008

In this paper, we first introduce a new method for joint estimation of IQ imbalance and channel r... more In this paper, we first introduce a new method for joint estimation of IQ imbalance and channel response in OFDM systems under the assumption of perfect frame synchronization. The proposed method needs only one OFDM block for training and the solution is given in closed form. Then the method is applied to the scenario when the OFDM frame is not synchronized. A reduced complexity algorithm is derived. With a relatively low complexity, the proposed method can accurately estimate the frame starting position, the IQ imbalance and the channel response simultaneously. Simulation results show that the bit error rate (BER) performance of the proposed method is very close to the ideal case when all these parameters are known perfectly at the receiver.

2017 IEEE 18th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC), 2017

In this paper we consider statistical beamforming for millimeter wave (mmWave) channels. For a co... more In this paper we consider statistical beamforming for millimeter wave (mmWave) channels. For a commonly used geometry channel model of uniform planar array (UPA), we show that the average channel Gram matrix can be approximated in a closed form, which allows the statistical beamformer to be computed directly. The sparse nature of the mmWave channel lends itself to statistical beamforming as the optimal beamformer that uses full channel information is typically steered in some spatial frequency determined by the statistics. Simulations are given to show that the performance of the proposed statistical beamformer that needs no instantaneous feedback is comparable to a limited feedback system with 1/8 feedback bits per antenna.

1996 IEEE Digital Signal Processing Workshop Proceedings

It is known that a continuous time signal z(t) with Fourier transform X (Y) band-limited to 1 .1 ... more It is known that a continuous time signal z(t) with Fourier transform X (Y) band-limited to 1 .1 < 8 / 2 can be reconstructed from its samples z(Ton) with To = 27r/@. In the case that X (Y) consists of two bands and is band-limited to vo < 1. 1 < v0+0/2, successful reconstruction of z(t) from z(T0n) requires that these two bands be located properly. When the two bands are not located properly, Kohlenberg showed that we can use a Periodically Nonuniform Sampling (PNS) scheme to recover z(t). In this paper, we show that PPJS scheme can be generalized and applied to a wider class. Further generalizations will be made to two-dimensional case and discrete-time case.

IEEE Transactions on Signal Processing, 2018

In this paper, we consider the design of statistical multiple-input-multiple-output orthogonal fr... more In this paper, we consider the design of statistical multiple-input-multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) beamformers for millimeter wave (mmWave) channels. The transmitter designs the subcarrier beamformers based on the statistics of the channel, without instantaneous channel information. To overcome the radio frequency (RF) limitation in mmWave application, the subcarrier beamformers are implemented in a hybrid structure, which imposes constraints on the design of subcarrier beamformers. We analyze the unconstrained statistical subcarrier beamformers using spectral analysis of the subcarrier channels. The analysis shows that, for each subcarrier channel, the optimal statistical beamformer is approximately a linear combination of optimal statistical beamformers for some appropriately defined narrowband single-cluster subchannels. The result suggests a design of the subcarrier beamformers that can be readily implemented in a hybrid structure. Furthermore, a hybrid design for the receiver is proposed based on the concept of vector quantization. Simulations are given to show that the use of a hybrid beamforming structure incurs a minor degradation in transmission rate. With three RF chains, the performance is close to that of all digital statistical beamforming. Index Terms-Hybrid precoding, wideband mmWave, statistical precoding, hybrid multiple-input-multiple-output orthogonal frequency division multiplexing (MIMO-OFDM). I. INTRODUCTION T HE performance of a MIMO system is known to improve with the number of antennas at the transmitter and receiver. Recent advances show that it is feasible to pack a large number of antennas in a small area, particularly in mmWave communication systems that use small wavelengths [1]. However cost and power constraints often prohibit having one dedicated RF chain for each antenna [2]. A promising technique to overcome the RF limitation is the so called hybrid scheme [3], [4], in which analog processing of RF signals is combined with digital processing in the baseband. Analog RF processing, due to power and complexity consideration, is typically implemented using phase shifters and the elements of the analog precoder are of unit modulus [5], [6]. Recently, it is shown in [7]-[9] that if two

IEEE Transactions on Signal Processing, 2015

In this paper, we consider variable-rate transmission over a slowly varying multiple-input multip... more In this paper, we consider variable-rate transmission over a slowly varying multiple-input multiple-output (MIMO) channel with a decision feedback receiver. The transmission rate is adapted to the channel by dynamically assigning bits to the subchannels of the MIMO system. Predictive quantization is used for the feedback of bit loading to take advantage of the time correlation inherited from the temporally correlated channel. Due to the use of decision feedback at the receiver, the bit loading is related to the Cholesky decomposition of the channel Gram matrix. Assuming the channel is modeled by a slowly varying Gauss-Markov process, we show that the nested submatrices generated during the process of Cholesky decomposition can be updated as time evolves. Based on the update, we derive the optimal predictor of the next bit loading for predictive quantization. Furthermore, we derive the statistics of the prediction error, which are then exploited to design the quantizer to achieve a smaller quantization error. Simulations are given to demonstrate that the proposed predictive quantization gives a good approximation of the desired transmission rate with a low feedback rate.

2016 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), 2016

For a time-correlated channel, we consider the differential feedback of the geometrical mean deco... more For a time-correlated channel, we consider the differential feedback of the geometrical mean decomposition (GMD) precoder, which is known to be optimal for a number of criteria. When the channel varies slowly, we can expect the optimal GMD precoders of consecutive channel uses to be close. We consider the feedback of the so-called differential precoder and show that it lies in a neighborhood of the identity matrix using matrix perturbation theory. Furthermore the radius of the neighborhood is proportional to a time-correlation parameter. Such a characterization is crucial for efficient quantization of the differential precoder. Simulations are given to demonstrate that, with a small feedback rate, the performance of the proposed differential GMD comes close to the case when perfect channel state information is available to the transmitter.

2008 IEEE International Conference on Acoustics, Speech and Signal Processing, 2008

Many coding methods are more efficient with certain types of images than others. In particular, r... more Many coding methods are more efficient with certain types of images than others. In particular, run-length coding is very useful for coding areas of little changes. Adaptive predictive coding achieves high coding efficiency for fast changing areas like edges. In this paper, we propose a switching coding scheme that will combine the advantages of both run-length and adaptive linear predictive

2015 IEEE International Conference on Communications (ICC), 2015

In this paper, we propose a MIMO precoding transceiver to achieve data secrecy at the physical la... more In this paper, we propose a MIMO precoding transceiver to achieve data secrecy at the physical layer. The proposed system exploits the Restricted Isometry Property (RIP) widely used in compressive sensing to encrypt the data. Because the channels at the legitimate receiver and the eavesdropper are inherently different, the corresponding sensing matrices are different. Thus the eavesdropper cannot decode the data successfully. More specifically, when full channel state information (CSI) at the legitimate receiver is known to the transmitter, the proposed precoder can simultaneously maximize receive SNR and attain secrecy. Simulation results corroborate theoretical results, and show that the proposed system enjoys different advantages when different recovery algorithms are used.

Filter Bank Transceivers for OFDM and DMT Systems

VTC-2005-Fall. 2005 IEEE 62nd Vehicular Technology Conference, 2005.

An approximately MAI-free multiaccess OFDM transceiver, called the precoded multiuser (PMU-OFDM) ... more An approximately MAI-free multiaccess OFDM transceiver, called the precoded multiuser (PMU-OFDM) OFDM system here, was proposed in (5). In this work, we extend results in (5), and propose a code priority scheme based on the even/odd Hadamard-Walsh code selection to enhance the performance of the PMU-OFDM system in a CFO environment. Based on the observation that different codewords have different

IEEE Transactions on Wireless Communications, 2015

This study investigates how to quantize the masked beamforming systems to maximize the secrecy ra... more This study investigates how to quantize the masked beamforming systems to maximize the secrecy rate for MISOSE (multiple-input, single-output, single-eavesdropper) channels and assume that this eavesdropper equipped with only single antenna, where only partial channel state information (CSI) at the legitimate receiver is available to the transmitter. In this case, the artificial noise (AN) leaks to the legitimate receiver due to CSI quantization. In the literature, all quantization bits are used to quantize the beamforming vector. Then the null space of this quantized beamforming vector is used to transmit the AN. We find that such quantization schemes can result in serious interference at the legitimate receiver. To overcome this issue, we propose that the beamforming vector and the AN vector should be quantized separately, where the beamforming vector should be selected from a codebook to maximize the beamforming gain and the AN vector should be selected from another codebook to minimize the leakage (or interference). Theoretical results show that separate quantization can significantly reduce the AN leakage at the legitimate receiver. Furthermore, based on the proposed quantization scheme, we show how to allocate bits to separately quantize the beamforming vector and the AN vector to maximize the secrecy rate. By using the proposed quantization and bit allocation schemes, the secrecy rates of masked beamforming systems can be improved compared to the conventional quantization schemes. Simulation results corroborate the theoretical results.

Proceedings. (ICASSP '05). IEEE International Conference on Acoustics, Speech, and Signal Processing, 2005.

ABSTRACT

2004 IEEE International Conference on Acoustics, Speech, and Signal Processing

ABSTRACT

2005 IEEE International Symposium on Circuits and Systems

ABSTRACT

IEEE 2002 International Conference on Communications, Circuits and Systems and West Sino Expositions

2001 IEEE International Conference on Acoustics, Speech, and Signal Processing. Proceedings (Cat. No.01CH37221), 2001

The design of optimal DMT transceivers for distorted channel with colored noise has been of great... more The design of optimal DMT transceivers for distorted channel with colored noise has been of great interest. Of particular interest is the class of block based DMT (BDMT), where the transmitter and the receiver consist of constant matrices. For a given channel and channel noise spectrum, the optimal DBMT transceiver that minimizes the transmission power for a fixed probability of error and transmission rate will be derived. The optimal biorthogonal transmitter is in fact orthogonal. That is, there is no loss of generality in using the orthogonal transmitter for the design optimal BDMT.

Signal Processing and Optimization for Transceiver Systems

Signal Processing and Optimization for Transceiver Systems

GLOBECOM '05. IEEE Global Telecommunications Conference, 2005., 2005

The performance of a multiuser OFDM transceiver, proposed by authors in [10] and called the preco... more The performance of a multiuser OFDM transceiver, proposed by authors in [10] and called the precoded multiuser OFDM (PMU-OFDM) in this work, with time asynchronous access is investigated. We show that the multiaccess interference (MAI) due to time asynchronous access can be reduced to a negligible amount by adopting a proper precoder that uses M/2 symmetric or M/2 anti-symmetric codewords of the M Hadamard-Walsh codes for the precoding task. The PMU-OFDM transceiver with the same precoder was shown to have approximately MAI-free property in a frequency asynchronous environment [11]. Here, we analyze the the approximately MAIfree property of the PMU-OFDM system with respect to time asynchronism. Finally, computer simulation is performed to confirm the derived property.

2008 IEEE International Conference on Acoustics, Speech and Signal Processing, 2008

In this paper, we first introduce a new method for joint estimation of IQ imbalance and channel r... more In this paper, we first introduce a new method for joint estimation of IQ imbalance and channel response in OFDM systems under the assumption of perfect frame synchronization. The proposed method needs only one OFDM block for training and the solution is given in closed form. Then the method is applied to the scenario when the OFDM frame is not synchronized. A reduced complexity algorithm is derived. With a relatively low complexity, the proposed method can accurately estimate the frame starting position, the IQ imbalance and the channel response simultaneously. Simulation results show that the bit error rate (BER) performance of the proposed method is very close to the ideal case when all these parameters are known perfectly at the receiver.

2017 IEEE 18th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC), 2017

In this paper we consider statistical beamforming for millimeter wave (mmWave) channels. For a co... more In this paper we consider statistical beamforming for millimeter wave (mmWave) channels. For a commonly used geometry channel model of uniform planar array (UPA), we show that the average channel Gram matrix can be approximated in a closed form, which allows the statistical beamformer to be computed directly. The sparse nature of the mmWave channel lends itself to statistical beamforming as the optimal beamformer that uses full channel information is typically steered in some spatial frequency determined by the statistics. Simulations are given to show that the performance of the proposed statistical beamformer that needs no instantaneous feedback is comparable to a limited feedback system with 1/8 feedback bits per antenna.

1996 IEEE Digital Signal Processing Workshop Proceedings

It is known that a continuous time signal z(t) with Fourier transform X (Y) band-limited to 1 .1 ... more It is known that a continuous time signal z(t) with Fourier transform X (Y) band-limited to 1 .1 < 8 / 2 can be reconstructed from its samples z(Ton) with To = 27r/@. In the case that X (Y) consists of two bands and is band-limited to vo < 1. 1 < v0+0/2, successful reconstruction of z(t) from z(T0n) requires that these two bands be located properly. When the two bands are not located properly, Kohlenberg showed that we can use a Periodically Nonuniform Sampling (PNS) scheme to recover z(t). In this paper, we show that PPJS scheme can be generalized and applied to a wider class. Further generalizations will be made to two-dimensional case and discrete-time case.

IEEE Transactions on Signal Processing, 2018

In this paper, we consider the design of statistical multiple-input-multiple-output orthogonal fr... more In this paper, we consider the design of statistical multiple-input-multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) beamformers for millimeter wave (mmWave) channels. The transmitter designs the subcarrier beamformers based on the statistics of the channel, without instantaneous channel information. To overcome the radio frequency (RF) limitation in mmWave application, the subcarrier beamformers are implemented in a hybrid structure, which imposes constraints on the design of subcarrier beamformers. We analyze the unconstrained statistical subcarrier beamformers using spectral analysis of the subcarrier channels. The analysis shows that, for each subcarrier channel, the optimal statistical beamformer is approximately a linear combination of optimal statistical beamformers for some appropriately defined narrowband single-cluster subchannels. The result suggests a design of the subcarrier beamformers that can be readily implemented in a hybrid structure. Furthermore, a hybrid design for the receiver is proposed based on the concept of vector quantization. Simulations are given to show that the use of a hybrid beamforming structure incurs a minor degradation in transmission rate. With three RF chains, the performance is close to that of all digital statistical beamforming. Index Terms-Hybrid precoding, wideband mmWave, statistical precoding, hybrid multiple-input-multiple-output orthogonal frequency division multiplexing (MIMO-OFDM). I. INTRODUCTION T HE performance of a MIMO system is known to improve with the number of antennas at the transmitter and receiver. Recent advances show that it is feasible to pack a large number of antennas in a small area, particularly in mmWave communication systems that use small wavelengths [1]. However cost and power constraints often prohibit having one dedicated RF chain for each antenna [2]. A promising technique to overcome the RF limitation is the so called hybrid scheme [3], [4], in which analog processing of RF signals is combined with digital processing in the baseband. Analog RF processing, due to power and complexity consideration, is typically implemented using phase shifters and the elements of the analog precoder are of unit modulus [5], [6]. Recently, it is shown in [7]-[9] that if two

IEEE Transactions on Signal Processing, 2015

In this paper, we consider variable-rate transmission over a slowly varying multiple-input multip... more In this paper, we consider variable-rate transmission over a slowly varying multiple-input multiple-output (MIMO) channel with a decision feedback receiver. The transmission rate is adapted to the channel by dynamically assigning bits to the subchannels of the MIMO system. Predictive quantization is used for the feedback of bit loading to take advantage of the time correlation inherited from the temporally correlated channel. Due to the use of decision feedback at the receiver, the bit loading is related to the Cholesky decomposition of the channel Gram matrix. Assuming the channel is modeled by a slowly varying Gauss-Markov process, we show that the nested submatrices generated during the process of Cholesky decomposition can be updated as time evolves. Based on the update, we derive the optimal predictor of the next bit loading for predictive quantization. Furthermore, we derive the statistics of the prediction error, which are then exploited to design the quantizer to achieve a smaller quantization error. Simulations are given to demonstrate that the proposed predictive quantization gives a good approximation of the desired transmission rate with a low feedback rate.

2016 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), 2016

For a time-correlated channel, we consider the differential feedback of the geometrical mean deco... more For a time-correlated channel, we consider the differential feedback of the geometrical mean decomposition (GMD) precoder, which is known to be optimal for a number of criteria. When the channel varies slowly, we can expect the optimal GMD precoders of consecutive channel uses to be close. We consider the feedback of the so-called differential precoder and show that it lies in a neighborhood of the identity matrix using matrix perturbation theory. Furthermore the radius of the neighborhood is proportional to a time-correlation parameter. Such a characterization is crucial for efficient quantization of the differential precoder. Simulations are given to demonstrate that, with a small feedback rate, the performance of the proposed differential GMD comes close to the case when perfect channel state information is available to the transmitter.

2008 IEEE International Conference on Acoustics, Speech and Signal Processing, 2008

Many coding methods are more efficient with certain types of images than others. In particular, r... more Many coding methods are more efficient with certain types of images than others. In particular, run-length coding is very useful for coding areas of little changes. Adaptive predictive coding achieves high coding efficiency for fast changing areas like edges. In this paper, we propose a switching coding scheme that will combine the advantages of both run-length and adaptive linear predictive

2015 IEEE International Conference on Communications (ICC), 2015

In this paper, we propose a MIMO precoding transceiver to achieve data secrecy at the physical la... more In this paper, we propose a MIMO precoding transceiver to achieve data secrecy at the physical layer. The proposed system exploits the Restricted Isometry Property (RIP) widely used in compressive sensing to encrypt the data. Because the channels at the legitimate receiver and the eavesdropper are inherently different, the corresponding sensing matrices are different. Thus the eavesdropper cannot decode the data successfully. More specifically, when full channel state information (CSI) at the legitimate receiver is known to the transmitter, the proposed precoder can simultaneously maximize receive SNR and attain secrecy. Simulation results corroborate theoretical results, and show that the proposed system enjoys different advantages when different recovery algorithms are used.

Filter Bank Transceivers for OFDM and DMT Systems

VTC-2005-Fall. 2005 IEEE 62nd Vehicular Technology Conference, 2005.

An approximately MAI-free multiaccess OFDM transceiver, called the precoded multiuser (PMU-OFDM) ... more An approximately MAI-free multiaccess OFDM transceiver, called the precoded multiuser (PMU-OFDM) OFDM system here, was proposed in (5). In this work, we extend results in (5), and propose a code priority scheme based on the even/odd Hadamard-Walsh code selection to enhance the performance of the PMU-OFDM system in a CFO environment. Based on the observation that different codewords have different

IEEE Transactions on Wireless Communications, 2015

This study investigates how to quantize the masked beamforming systems to maximize the secrecy ra... more This study investigates how to quantize the masked beamforming systems to maximize the secrecy rate for MISOSE (multiple-input, single-output, single-eavesdropper) channels and assume that this eavesdropper equipped with only single antenna, where only partial channel state information (CSI) at the legitimate receiver is available to the transmitter. In this case, the artificial noise (AN) leaks to the legitimate receiver due to CSI quantization. In the literature, all quantization bits are used to quantize the beamforming vector. Then the null space of this quantized beamforming vector is used to transmit the AN. We find that such quantization schemes can result in serious interference at the legitimate receiver. To overcome this issue, we propose that the beamforming vector and the AN vector should be quantized separately, where the beamforming vector should be selected from a codebook to maximize the beamforming gain and the AN vector should be selected from another codebook to minimize the leakage (or interference). Theoretical results show that separate quantization can significantly reduce the AN leakage at the legitimate receiver. Furthermore, based on the proposed quantization scheme, we show how to allocate bits to separately quantize the beamforming vector and the AN vector to maximize the secrecy rate. By using the proposed quantization and bit allocation schemes, the secrecy rates of masked beamforming systems can be improved compared to the conventional quantization schemes. Simulation results corroborate the theoretical results.

Proceedings. (ICASSP '05). IEEE International Conference on Acoustics, Speech, and Signal Processing, 2005.

ABSTRACT

2004 IEEE International Conference on Acoustics, Speech, and Signal Processing

ABSTRACT

2005 IEEE International Symposium on Circuits and Systems

ABSTRACT

IEEE 2002 International Conference on Communications, Circuits and Systems and West Sino Expositions

2001 IEEE International Conference on Acoustics, Speech, and Signal Processing. Proceedings (Cat. No.01CH37221), 2001

The design of optimal DMT transceivers for distorted channel with colored noise has been of great... more The design of optimal DMT transceivers for distorted channel with colored noise has been of great interest. Of particular interest is the class of block based DMT (BDMT), where the transmitter and the receiver consist of constant matrices. For a given channel and channel noise spectrum, the optimal DBMT transceiver that minimizes the transmission power for a fixed probability of error and transmission rate will be derived. The optimal biorthogonal transmitter is in fact orthogonal. That is, there is no loss of generality in using the orthogonal transmitter for the design optimal BDMT.

Signal Processing and Optimization for Transceiver Systems

Signal Processing and Optimization for Transceiver Systems

GLOBECOM '05. IEEE Global Telecommunications Conference, 2005., 2005

The performance of a multiuser OFDM transceiver, proposed by authors in [10] and called the preco... more The performance of a multiuser OFDM transceiver, proposed by authors in [10] and called the precoded multiuser OFDM (PMU-OFDM) in this work, with time asynchronous access is investigated. We show that the multiaccess interference (MAI) due to time asynchronous access can be reduced to a negligible amount by adopting a proper precoder that uses M/2 symmetric or M/2 anti-symmetric codewords of the M Hadamard-Walsh codes for the precoding task. The PMU-OFDM transceiver with the same precoder was shown to have approximately MAI-free property in a frequency asynchronous environment [11]. Here, we analyze the the approximately MAIfree property of the PMU-OFDM system with respect to time asynchronism. Finally, computer simulation is performed to confirm the derived property.