Search results for: Yuan-Pei Lin
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IEEE Transactions on Signal Processing > 2017 > 65 > 14 > 3833 - 3845
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...
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Recently it is shown that the maximum MIMO beamforming gain can be achieved using only one RF (radio frequency) chain. This is done by implementing the beamformer using Two analog pHase shIfters for each Coefficient (THIC). In this paper we analyze the quantization error of the beamforming coefficients (weights) when the phase shifters used in THIC are of finite resolution. An alternative THIC structure...
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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...
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IEEE Transactions on Signal Processing > 2017 > 65 > 9 > 2237 - 2246
Hybrid precoding that combines analog RF processing and digital baseband processing has been shown to be a promising technique for transceivers with limited number of RF chains. The RF processing, due to power and complexity issue, is typically done by using phase shifters. A recent study shows that hybrid precoding is no loss of generality if each coefficient of the analog precoder is implemented...
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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...
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IEEE Transactions on Wireless Communications > 2015 > 14 > 10 > 5616 - 5628
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...
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In this paper, we consider limited feedback for MIMO channels that have time and spatial correlation. The bit loading is dynamically assigned according to the channel condition and fed back to the transmitter to achieve an adaptive rate. To take advantage of the time correlation of the channel, the bit loading is predictively coded for feedback. The precoder is designed according to the statistics...
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IEEE Transactions on Signal Processing > 2015 > 63 > 13 > 3376 - 3386
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...
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In the paper, we consider limited feedback for a MIMO-OFDM system over a time-correlated multipath fading channel. Due to time correlation, the subcarriers are correlated in both time and frequency. We propose the use of predictive quantization of bit loading (PQB) and subcarrier clustering (SC). Applying PQB on the subcarriers allows us to exploit the time correlation of the channel and adapt the...
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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...
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Recently there has been considerable interest in the design of optimal paraunitary filter banks for a given class of inputs. In this paper we address a number of practical considerations associated with the design and implementation of optimal paraunitary filter banks.
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In this paper, we study DFT bank transceivers with filter length longer than the block size. Given a fixed transmit (or receive) prototype filter, it has been shown recently that we are able to design the receive (or correspondingly transmit) prototype filter so that the signal to interference ratio (SIR) is maximized for multipath fading channels. However only the transmit (or receive) filters are...
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We introduce an efficient method for the design of causal stable IIR filter bank (FB) with Powers-of-two coefficients. Ladder structure is used to construct the IIR FBs with perfect reconstruction (PR). In the proposed method, FBs with real coefficients are first designed and an iterative procedure is then employed to discretize the coefficients. A sensitivity measure is introduced to determine the...
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The DMT (discrete multitone modulation) transceivers have been shown to be a very useful technique for data transmission over frequency selective channels. The DMT scheme is realized by a transceiver that divides the channel into subbands. The efficiency of the scheme depends on the frequency selectivity of the tranceiving filters. The filterbank transceiver or DWMT (discrete wavelet multitone) system,...
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The uniform DFT filter bank has been used routinely in discrete multitone modulation (DMT) systems because of implementation efficiency. It has recently been shown that principal component filter banks (PCFB) which are known to be optimal for data compression and denoising applications, are also optimal for a number of criteria in DMT communication. In this paper we show that such filter banks are...
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Carrier frequency offset (CFO) is an important issue in orthogonal frequency division multiplexing (OFDM) systems. It destroys the orthogonality between subcarriers and causes degradation in system performance. This paper presents an improved algorithm for the existing ESPRIT-based CFO estimation method. The proposed method estimates the CFO by taking the determinant of a matrix within the ESPRIT...
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In this paper we consider variable-rate transmission for time-correlated MIMO (multi-input multi-output) channels with limited feedback. The number of bits loaded on each subchannel of the MIMO system is dynamically assigned according to the current channel condition and fed back to the transmitter. As the channel is time-correlated, so is bit loading. We propose to feedback bit loading using predictive...
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IEEE Transactions on Signal Processing > 2014 > 62 > 19 > 5085 - 5094
In this paper we consider variable-rate transmission for time-correlated MIMO (multi-input multi-output) channels with limited feedback. The number of bits loaded on each subchannel of the MIMO system is dynamically assigned according to the current channel condition and fed back to the transmitter. As the channel is time-correlated, bit loading is a vector signal that is also time-correlated. We...
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IEEE Transactions on Information Forensics and Security > 2014 > 9 > 5 > 801 - 813
In this paper, we propose an MIMO precoding and postcoding transceiver to achieve data secrecy at the physical layer. When full channel state information (CSI) of the legitimate receiver is known to the transmitter, the proposed precoder can simultaneously maximize to receive signal-to-noise ratio (SNR) and attain secrecy. When only partial CSI is available, a modified Lloyd algorithm is proposed...
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In this paper we propose to use multiple precoder codebooks for MIMO systems with limited feedback of precoder and bit loading. One precoder codebook is designed for each bit loading vector in the bit loading codebook as bit loading contains information on the importance of individual subchannels. For each precoder codebook, we incorporate the associated bit loading in codebook design to minimize...
