147 results on '"Yuan, Pei"'
Search Results
2. Improving Angle Estimation via Feedback for Hybrid mmWave Systems Using Beamforming Virtual Arrays
- Author
-
Lin, Yuan-Pei and Chiew, Yu-Tai
- Abstract
It is known that when there is some rough knowledge on the angles of arrivals (AoAs) and angles of departures (AoDs), beamforming can increase the received SNR for finer angle estimation. Beamforming aided angle estimation generally requires two stages or more. Estimation performance depends on the allocation of training time and feedback bits between the two stages. In this paper, we consider the allocation of training time and feedback bits of a two-stage angle estimation scheme for a hybrid mmWave system that has limited feedback rate. Banded Toeplitz matrices are used for precoding and combining to obtain beamforming virtual uniform linear arrays (BV-ULA). Using properly designed banded Toeplitz precoders and combiners, the equivalent path gains are boosted by beamforming gain while the overall system is equivalent to one equipped virtual ULAs but without precoding and combining. Virtual ULAs allow us to conduct angle estimation as if there are no precoder and combiner; most existing angle estimation methods can be applied. Due to finite feedback rate, the AoDs are quantized before they are fed back to the transmitter. The AoD estimates available to the transmitter contain both quantization and angle estimation errors. We derive the overall error, which depends on how the training time and feedback bits are allocated to the two stages. For the useful case of high feedback rate, we show that the training vectors should be equally allocated to the two stages. Simulations show that the proposed BV-ULA approach can considerably improve the SNR at the second stage and achieve high resolution.
- Published
- 2024
- Full Text
- View/download PDF
3. Improving Angle Estimation via Feeback for Hybrid mmWave Systems using Beamforming Virtual Arrays
- Author
-
Lin, Yuan-Pei, primary and Chiew, Yu-Tai, additional
- Published
- 2023
- Full Text
- View/download PDF
4. Hybrid MIMO-OFDM Beamforming for Wideband mmWave Channels Without Instantaneous Feedback
- Author
-
Yuan-Pei Lin
- Subjects
Beamforming ,Orthogonal frequency-division multiplexing ,Computer science ,Transmitter ,020206 networking & telecommunications ,020302 automobile design & engineering ,02 engineering and technology ,MIMO-OFDM ,Subcarrier ,Signal-to-noise ratio ,Narrowband ,0203 mechanical engineering ,Signal Processing ,0202 electrical engineering, electronic engineering, information engineering ,Electronic engineering ,Electrical and Electronic Engineering ,Wideband ,Communication channel - Abstract
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.
- Published
- 2018
5. A new iterative algorithm for finding the minimum sampling frequency of multiband signals
- Author
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Yuan-Pei Lin, Yi-De Liu, and See-May Phoong
- Subjects
Electric filters, Bandpass -- Innovations ,Signal processing -- Innovations ,Frequency modulation -- Analysis ,Simulation methods -- Usage ,Bandwidth -- Measurement ,Digital signal processor ,Bandwidth allocation ,Bandwidth technology ,Business ,Computers ,Electronics ,Electronics and electrical industries - Published
- 2010
6. ISI-free block transceivers for unknown frequency selective channels
- Author
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Chih-Hao Liu, See-May Phoong, and Yuan-Pei Lin
- Subjects
Transceivers -- Design and construction ,Signal processing -- Methods ,Transceiver ,Digital signal processor ,Business ,Computers ,Electronics ,Electronics and electrical industries - Abstract
The general block transceiver with channel-induced intersymbol interference (ISI)-free property is analyzed. The results have shown that except for some special cases, the solutions are identical to Lagrange-Vandermonde and Vandermonde-Lagrange transceivers.
- Published
- 2007
7. An eigen-based TEQ design for VDSL systems
- Author
-
Yuan-Pei Lin, Li-Han Liang, See-May Phoong, and Pei-Ju Chung
- Subjects
Signal processing -- Methods ,Digital Subscriber Line -- Research ,Eigenfunctions -- Usage ,Digital signal processor ,DSL ,Business ,Computers ,Electronics ,Electronics and electrical industries - Abstract
An eigen-based semiblind time-domain equalizer (TEQ) design method is proposed for VDSL systems. The results have shown that the TEQ design method can shorten the channel impulse response and achieve good bit rates with only a small number of training symbols.
- Published
- 2007
8. MAI-free MC-CDMA systems based on Hadamard-Walsh code
- Author
-
Sheng-Ho Tsai, Yuan-Pei Lin, and Kuo, C.-C Jay
- Subjects
CDMA technology -- Usage ,Walsh functions -- Analysis ,Frequency estimation -- Methods ,Code Division Multiple Access technology ,Business ,Computers ,Electronics ,Electronics and electrical industries - Abstract
A Hadamard-Walsh code-based multicarrier code-division multiple-access (MC-CDMA) system that achieves zero multi-access interference (MAI) over a frequency-selective fading channel is proposed. It is also shown that the MAI-free property allows to estimate the channel of each user separately and the system can perform channel estimation easily.
- Published
- 2006
9. An approximately MAI-free multiaccess OFDM system in carrier frequency offset environment
- Author
-
Shang-Ho Tsai, Yuan-Pei Lin, and C.-C. Jay Kuo
- Subjects
Synchronous communications -- Research ,Business ,Computers ,Electronics ,Electronics and electrical industries - Abstract
The carrier frequency offset (CFO) effect of a new multiaccess orthogonal frequency division multiplexing transceiver is analyzed and shows that multiaccess interference due to CFO can be mitigated by choosing a proper set of orthogonal codes. Results show that it does not demand sophisticated multiuser detection or signal processing in achieving multiuser communications, and CFO compensation can be done at the receiver side.
- Published
- 2005
10. Window designs for DFT-based multicarrier systems
- Author
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Yuan-Pei Lin and See-May Phoong
- Subjects
Signal processing -- Research ,Fourier transformations -- Analysis ,Digital signal processor ,Business ,Computers ,Electronics ,Electronics and electrical industries - Abstract
Window designs for discrete fourier transform (DFT) based multicarrier transceivers without using extra cyclic prefix are considered. It is shown that postprocessing is channel independent if and only if the window itself has the cyclic-prefixed property.
- Published
- 2005
11. OFDM transmitters: analog representation and DFT-based implementation
- Author
-
Lin, Yuan-Pei and Phoong, See-May
- Subjects
Multichannel communication -- Research ,Multiplexing -- Research ,Digital multiplexing -- Research ,Signal processing -- Research ,Digital signal processor ,Business ,Computers ,Electronics ,Electronics and electrical industries - Abstract
It is shown that the analog representation and DFT-based OFDM systems are only equivalent in special cases.
- Published
- 2003
12. BER Minimized OFDM systems with channel independent precoders
- Author
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Lin, Yuan-Pei and Phoong, See-May
- Subjects
Signal processing -- Research ,Digital signal processor ,Business ,Computers ,Electronics ,Electronics and electrical industries - Abstract
Minimization of uncoded BER for the class of OFDM tranceivers with unitary precoders is examined and discussed.
- Published
- 2003
13. Lapped unimodular transform and its factorization
- Author
-
Phoong, See-May and Lin, Yuan-Pei
- Subjects
Electric filters -- Research ,Signal processing -- Research ,Digital signal processor ,Business ,Computers ,Electronics ,Electronics and electrical industries - Abstract
It is shown that, as with lapped orthogonal transforms (LOT) and biorthogonal lapped transforms (BOLT), all lapped unimodular transforms (LUT) can be minimally factorized. It is also shown that all first-order matrices with finite impulse response (FIR) inverse can be decomposed into a cascade of degree-one LOT, degree-one BOLT, and degree-one LUT building blocks.
- Published
- 2002
14. Minimum redundancy for ISI free FIR filterbank transceivers
- Author
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Lin, Yuan-Pei and Phoong, See-May
- Subjects
Filtering (Electronics) -- Research ,Signal processing -- Research ,Electronics industry -- Research ,Transceivers -- Research ,Electronics industry ,Digital signal processor ,Transceiver ,Business ,Computers ,Electronics ,Electronics and electrical industries - Abstract
It is shown that for an interpolation ratio N, the minimum redundancy or the maximum number of bands usable for finite impulse response (FIR) transceivers can be accurately determined. It is shown that minimum redundancy is directly dependent on the number of congruous zeros of the channel and to the Smith form of a properly defined channel matrix.
- Published
- 2002
15. Optimal ISI-free DMT transceivers for distorted channels with colored noise
- Author
-
Lin, Yuan-Pei and Phoong, See-May
- Subjects
Signal processing -- Research ,Business ,Computers ,Electronics ,Electronics and electrical industries - Abstract
Two classes of block-based discrete multitone (DMT) transceivers are examined: the system with a general prefix (GP-DMT); and the system with zero padding (ZP-DMT). It is shown that optimal transceivers that minimize the transmission power for a given bit rate and probability can be provided in closed form.
- Published
- 2001
16. ISI-free FIR filterbank transceivers for frequency-selective channels
- Author
-
Lin, Yuan-Pei and Phoong, See-May
- Subjects
Signal processing -- Research ,Transceivers -- Research ,Business ,Computers ,Electronics ,Electronics and electrical industries - Abstract
How to use over interpolated filterbanks to design intersymbol interference (ISI)-free finite impulse response (FIR) transceivers is described. Design examples are provided.
- Published
- 2001
17. Prediction-based lower triangular transform
- Author
-
Phoong, See-May and Lin, Yuan-Pei
- Subjects
Signal processing -- Research ,Business ,Computers ,Electronics ,Electronics and electrical industries - Abstract
A prediction-based lower triangular transform is presented.
- Published
- 2000
18. Differential Feedback of Geometrical Mean Decomposition Precoder for Time-Correlated MIMO Systems
- Author
-
Yuan-Pei Lin and Hung-Chun Chen
- Subjects
Quantization (signal processing) ,MIMO ,Identity matrix ,020206 networking & telecommunications ,020302 automobile design & engineering ,02 engineering and technology ,Topology ,QR decomposition ,Matrix decomposition ,Matrix (mathematics) ,0203 mechanical engineering ,Channel state information ,Control theory ,Signal Processing ,0202 electrical engineering, electronic engineering, information engineering ,Electrical and Electronic Engineering ,Computer Science::Information Theory ,Communication channel ,Mathematics - Abstract
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 shown to be proportional to a time-correlation parameter. Such a characterization allows for subsequent efficient quantization of the differential precoder. We show how to design codewords for the prescribed radius by perturbing the identity matrix and applying QR decomposition on the perturbed matrix. 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 for slowly time-varying channels like those in indoor and microcellular environments.
- Published
- 2017
19. On the Quantization of Phase Shifters for Hybrid Precoding Systems
- Author
-
Yuan-Pei Lin
- Subjects
Computer science ,Quantization (signal processing) ,020302 automobile design & engineering ,020206 networking & telecommunications ,02 engineering and technology ,Topology ,Precoding ,0203 mechanical engineering ,Control theory ,Signal Processing ,0202 electrical engineering, electronic engineering, information engineering ,Baseband ,Electrical and Electronic Engineering ,Phase shift module ,Computer Science::Information Theory - Abstract
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 by using two phase shifters. In this paper, we consider two possible implementation structures that use Two pHase shIfters for each Coefficient (THIC). These two structures, having the same performance when the phases can take on continuum values, behave differently upon quantization, as the analysis shows. For a small number of quantization bits, the precoder implemented using THIC is a good approximation of the unquantized one. With 3-bit phase shifters, the performance is close to that of the unquantized system in multiuser communications, where the performance is more sensitive to quantization errors. While the analysis in this paper is done assuming high-resolution quantization, simulations show that the result is accurate even for coarse quantization.
- Published
- 2017
20. On the study of four-parallelogram filter banks
- Author
-
Lin, Yuan-Pei and Vaidyanathan, P.P.
- Subjects
Signal processing -- Research ,Filtering (Electronics) -- Innovations ,Business ,Computers ,Electronics ,Electronics and electrical industries - Abstract
A four parallelogram filter bank is a type of two-dimensional filter bank in which the analysis and synthesis filters are supported by four parallelograms. The choice of integer matrix and the location of the four parallelograms control the type of configuration for these filter banks. Derivation of design condition for analysis and synthesis filters shows that a unique category of configurations exists for four-parallelogram filter banks. The configurations in this category are obtained by designing low-cost filter banks.
- Published
- 1996
21. Theory and design of two-parallelogram filter banks
- Author
-
Lin, Yuan-Pei and Vaidyanathan, P.P.
- Subjects
Signal processing -- Research ,Filtering (Electronics) -- Innovations ,Business ,Computers ,Electronics ,Electronics and electrical industries - Abstract
The passbands of each analysis filter in two-parallelogram filter banks consist of two parallelograms. Parallelogram cells partition the frequency plane. These filter banks can have either edge permissibility or vertex permissibility but not both. This keeps the stopband attenuation of the filters at a low level. The cosine-modulated filter bank (CMFB) is a special type of two-parallelogram filter bank in which the analysis and synthesis filters are cosine-modulated versions of a parallelogram-supported prototype. The conditions for the reconstruction of the CMFB are derived.
- Published
- 1996
22. Linear phase cosine modulated maximally decimated filter banks with perfect reconstruction
- Author
-
Lin, Yuan-Pei and Vaidyanathan, P.P.
- Subjects
Signal processing -- Research ,Digital filters -- Research ,Business ,Computers ,Electronics ,Electronics and electrical industries - Abstract
The analysis and synthesis filters of maximally decimated FIR cosine modulated filter banks have a linear phase within a new design system for these filters. The coding gain of the system is comparable to that of a traditional M-channel system due to the use of two band-pass filters with a similar passband support. The system design can have either the approximate reconstruction property or perfect reconstruction property. The system has good attenuation characteristics, and is efficient.
- Published
- 1995
23. Hybrid MIMO-OFDM Beamforming for Wideband mmWave Channels Without Instantaneous Feedback
- Author
-
Lin, Yuan-Pei, primary
- Published
- 2018
- Full Text
- View/download PDF
24. Predictive Coding of Bit Loading for Time-Correlated MIMO Channels With a Decision Feedback Receiver
- Author
-
Yuan-Pei Lin and Chien-Chang Li
- Subjects
Predictive coding ,Quantization (signal processing) ,MIMO ,Block matrix ,Data_CODINGANDINFORMATIONTHEORY ,Precoding ,Matrix decomposition ,Control theory ,Signal Processing ,Electrical and Electronic Engineering ,Computer Science::Information Theory ,Gramian matrix ,Cholesky decomposition ,Mathematics - Abstract
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.
- Published
- 2015
25. Variable-Rate Transmission for MIMO Time-Correlated Channels With Limited Feedback
- Author
-
Yuan-Pei Lin
- Subjects
Correlation coefficient ,Transmission (telecommunications) ,Stochastic process ,Control theory ,Signal Processing ,Transmitter ,MIMO ,Codebook ,Electrical and Electronic Engineering ,Signal ,Computer Science::Information Theory ,Communication channel ,Mathematics - Abstract
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 sub- channel 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 propose to feedback bit loading using predictive coding, which is known to be a powerful quanti- zation technique when the underlying signal is correlated in time. Assuming the channel is a first-order Gauss-Markov random process, we derive the predictor for the bit loading to be coded and analyze the corresponding prediction error variance when the channel is varying slowly. By exploiting the prediction error variance, we adapt the quantizer of the prediction error to have a smaller quantization error. Furthermore we show that the pre- diction error variance is proportional to a term that depends only on the time-correlation coefficient. This leads to the conclusion that, a codebook that is designed for a particular time correlation coefficient can be easily modified to a codebook for a different correlation coefficient without redesign. Simulations are presented to demonstrate that the proposed predictive coding can achieve a very good approximation of the desired transmission rate with a very low feedback rate.
- Published
- 2014
26. Limited Feedback of Precoder and Bit Loading for MIMO Systems: A Joint Design
- Author
-
Yuan-Pei Lin and Hung-Chun Chen
- Subjects
Computer science ,Control theory ,Quantization (signal processing) ,Signal Processing ,Transmitter ,Codebook ,Codec ,Electrical and Electronic Engineering ,Precoding ,Mimo systems - Abstract
This paper jointly considers limited feedback of bit loading and precoder. In the past when both precoder and bit loading are fed back to the transmitter, the feedback rate is often allocated between the two using an ad hoc approach and codebooks are designed separately rather than jointly. In this paper we allocate feedback rate in a systematic manner by analyzing the effect of quantization on transmission power. The analysis allows us to obtain the rate allocation that minimizes the power penalty due to limited feedback. As both precoder and bit loading are fed back to the transmitter, the information embedded in one can be exploited for the design of the other. To take advantage of bit loading feedback, which carries valuable information on the importance of individual subchannels, we employ multiple precoder codebooks, each tailored to a bit loading vector in the bit loading codebook. The multi-codebook scheme enjoys significant gain over the single-codebook case that does not take bit loading feedback into consideration. Simulations are given to demonstrate that the proposed system can achieve a very good performance due to carefully designed feedback rate allocation and joint codebook designs.
- Published
- 2013
27. Lattice Quantization of Phases for Equal Gain Transmission
- Author
-
Yuan-Pei Lin and Shang-Ho Tsai
- Subjects
Combinatorics ,Beamforming ,Grassmannian ,Quantization (signal processing) ,Lattice (order) ,Signal Processing ,Binary number ,Lattice quantization ,Code rate ,Electrical and Electronic Engineering ,Topology ,Precoding ,Mathematics - Abstract
Equal gain transmission (EGT) requires only the feedback of phase information and is known to enjoy several implementational advantages compared to maximum ratio transmission (MRT). This paper investigates the use of lattice quantization for quantizing phases in EGT systems. In practice, the feedback rate is finite and the lattices need to be truncated to have finite code rate. The truncation of lattices results in boundary effect; hence, earlier results developed for untruncated lattices, e.g., fast algorithm and mean-square error (MSE) analysis, cannot be applied directly. Exploiting the fact that the quantized signals are phases, we show how to quantize using truncated lattices so that there is no boundary effect. Moreover, we propose efficient methods to convert between lattice codewords and binary digits so that the lattice quantization can be used in practical systems. Furthermore, the mean-square quantization error is analyzed for several useful truncated lattices. We also show how to analyze the signal-to-noise ratio (SNR) loss when the proposed quantization is applied to an EGT system.
- Published
- 2012
28. On the Duality of MIMO Transceiver Designs With Bit Allocation
- Author
-
Chien-Chang Li and Yuan-Pei Lin
- Subjects
Mathematical optimization ,Channel allocation schemes ,Signal Processing ,Duality (mathematics) ,Converse ,MIMO ,Bit error rate ,Maximization ,Electrical and Electronic Engineering ,Transceiver ,Communications system ,Mathematics - Abstract
Bit rate and power are two commonly used optimality criteria for MIMO transceiver design. In the literature, bit rate maximization and power minimization problems are viewed as different problems and solved independently. In this paper, we derive the duality between these two problems for both the cases with and without integer constraint on bit allocation. We will show that if a transceiver is optimal for the power-minimizing problem, it is also optimal for the rate maximizing problem, and the converse is true. Such a duality has not been stated and proved in the literature to the best of our knowledge. The derivation does not involve any existing optimal solution and we can establish duality result even for the rate maximization problem with integer bit constraint, which the optimal solution is not known. The duality also allows us to develop an algorithm for finding the rate-maximizing transceiver with integer bit allocation using the solution of power-minimizing system. We will also consider some possible generalizations of the problem, for example, when there is a constraint on the maximal constellation size and when the subchannel bit error rates (BERs) are constrained. For each of these cases, we will see that the duality between the two problems continued to hold. In the simulations, we will compute the optimal solutions for these two problems and demonstrate the duality between these two.
- Published
- 2011
29. A New Iterative Algorithm for Finding the Minimum Sampling Frequency of MultiBand Signals
- Author
-
Yi-De Liu, See-May Phoong, and Yuan-Pei Lin
- Subjects
Signal processing ,Iterative method ,Computer science ,Nonuniform sampling ,Sampling (statistics) ,Software-defined radio ,Time–frequency analysis ,Sampling (signal processing) ,Band-pass filter ,Undersampling ,Coherent sampling ,Signal Processing ,Statistics ,Electrical and Electronic Engineering ,Algorithm ,Passband - Abstract
In this correspondence, we propose a new iterative algorithm for finding the minimum sampling frequency of a signal that consists of multiple bandpass signals. This finds important application in software radio where it is desirable to downconvert multiple bandpass signals simultaneously. We will derive a new set of conditions for alias-free sampling. The minimum sampling frequency can be found by iteratively increasing the sampling frequency to meet the alias-free conditions. We will show how the algorithm can be generalized to find alias-free sampling frequency intervals. Simulations will be given to demonstrate the usefulness of the proposed method.
- Published
- 2010
30. Differential Feedback of Geometrical Mean Decomposition Precoder for Time-Correlated MIMO Systems.
- Author
-
Chen, Hung-Chun and Lin, Yuan-Pei
- Subjects
DIFFERENTIAL equations ,MIMO systems ,MICROCELLULAR networks (Telecommunication) ,EQUALIZERS (Electronics) ,MATRICES (Mathematics) - Abstract
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 shown to be proportional to a time-correlation parameter. Such a characterization allows for subsequent efficient quantization of the differential precoder. We show how to design codewords for the prescribed radius by perturbing the identity matrix and applying QR decomposition on the perturbed matrix. 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 for slowly time-varying channels like those in indoor and microcellular environments. [ABSTRACT FROM PUBLISHER]
- Published
- 2017
- Full Text
- View/download PDF
31. On the Quantization of Phase Shifters for Hybrid Precoding Systems.
- Author
-
Lin, Yuan-Pei
- Subjects
SIGNAL quantization ,PHASE shifters ,MIMO systems ,RADIO frequency ,SIGNAL-to-noise ratio - Abstract
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 by using two phase shifters. In this paper, we consider two possible implementation structures that use Two pHase shIfters for each Coefficient (THIC). These two structures, having the same performance when the phases can take on continuum values, behave differently upon quantization, as the analysis shows. For a small number of quantization bits, the precoder implemented using THIC is a good approximation of the unquantized one. With 3-bit phase shifters, the performance is close to that of the unquantized system in multiuser communications, where the performance is more sensitive to quantization errors. While the analysis in this paper is done assuming high-resolution quantization, simulations show that the result is accurate even for coarse quantization. [ABSTRACT FROM PUBLISHER]
- Published
- 2017
- Full Text
- View/download PDF
32. MAI-Free MC-CDMA Systems Based on Hadamard–Walsh Codes
- Author
-
Shang-Ho Tsai, C.-C.J. Kuo, and Yuan-Pei Lin
- Subjects
Carrier signal ,Hadamard code ,business.industry ,Computer science ,Code division multiple access ,Code word ,Data_CODINGANDINFORMATIONTHEORY ,Multiuser detection ,Error exponent ,Hadamard transform ,Diversity gain ,Carrier frequency offset ,Signal Processing ,Bit error rate ,Frequency offset ,Fading ,Constant-weight code ,Electrical and Electronic Engineering ,Telecommunications ,business ,Algorithm ,Multipath propagation ,Decoding methods ,Computer Science::Information Theory ,Communication channel - Abstract
It is known that multicarrier code-division multiple-access (MC-CDMA) systems suffer from multiaccess interference (MAI) when the channel is frequency-selective fading. In this paper, we propose a Hadamard-Walsh code-based MC-CDMA system that achieves zero MAI over a frequency-selective fading channel. In particular, we will use appropriately chosen subsets of Hadamard-Walsh code as codewords. For a multipath channel of length L, we partition a Hadamard-Walsh code of size N into G subsets, where G is a power of two with GgesL. We will show that the N/G codewords in any of the G subsets yields an MAI-free system. That is, the number of MAI-free users for each codeword subset is N/G. Furthermore, the system has the additional advantage that it is robust to carrier frequency offset (CFO) in a multipath environment. It is also shown that the MAI-free property allows us to estimate the channel of each user separately and the system can perform channel estimation much more easily. Owing to the MAI-free property, every user can enjoy a channel diversity gain of order L to improve the bit error performance. Finally, we discuss a code priority scheme for a heavily loaded system. Simulation results are given to demonstrate the advantages of the proposed code and code priority schemes
- Published
- 2006
33. An approximately MAI-free multiaccess OFDM system in carrier frequency offset environment
- Author
-
Yuan-Pei Lin, Shang-Ho Tsai, and C.-C.J. Kuo
- Subjects
Carrier signal ,Frequency-division multiple access ,Code division multiple access ,Computer science ,business.industry ,Orthogonal frequency-division multiplexing ,Interference (wave propagation) ,Multiuser detection ,Carrier frequency offset ,Signal Processing ,Electronic engineering ,Frequency offset ,Electrical and Electronic Engineering ,Transceiver ,Telecommunications ,business - Abstract
The carrier frequency offset (CFO) effect of a new multiaccess orthogonal frequency division multiplexing (OFDM) transceiver is analyzed. We show that multiaccess interference (MAI) due to CFO can be mitigated by choosing a proper set of orthogonal codes. That is, if we use M/2 symmetric or antisymmetric codewords of the M Hadamard-Walsh codewords, MAI can be greatly reduced to a negligible amount. The new OFDM system has been shown to be approximately MAI-free when there is no CFO. The new result developed here shows that the system continues to be approximately MAI-free even in the presence of CFO. Furthermore, we derive a close form for the reduced MAI, which reveals an interesting property of the system. That is, when the number of users increases, the reduced MAI and the inter carrier interference (ICI) due to self-CFO will decrease. Finally, it is demonstrated by simulation that the proposed OFDM scheme with proper code selection outperforms the OFDMA and the multicarrier code division multiplexing access (MC-CDMA) systems in a CFO environment.
- Published
- 2005
34. Window designs for DFT-based multicarrier systems
- Author
-
See-May Phoong and Yuan-Pei Lin
- Subjects
Signal processing ,Computer science ,business.industry ,Spectral density ,Window (computing) ,Filter (signal processing) ,Discrete Fourier transform ,Cyclic prefix ,Reduction (complexity) ,Intersymbol interference ,Embedded system ,Signal Processing ,Electrical and Electronic Engineering ,business ,Algorithm ,Spectral leakage ,Computer Science::Information Theory - Abstract
We consider window designs for discrete Fourier transform (DFT) based multicarrier transceivers without using extra cyclic prefix. As in previous works of window designs for DFT-based transceivers, a postprocessing matrix that is generally channel dependent, is needed to have a zero-forcing receiver. We show that postprocessing is channel independent if and only if the window itself has the cyclic-prefixed property. We design optimal windows with minimum spectral leakage subject to the cyclic-prefixed condition. Moreover, we analyze how postprocessing affects the signal-to-noise ratio (SNR) at the receiver, which is an aspect that is not considered in most of the earlier works. The resulting SNR can be given in a closed form. Join optimization of spectral leakage and SNR are also considered. Furthermore, examples demonstrate that we can have a significant reduction in spectral leakage at the cost of a small SNR loss. In addition to cyclic-prefixed systems, window designs for zero-padded DFT-based transceivers are considered. For the zero-padded transceivers, windows that minimize spectral leakage can also be designed.
- Published
- 2005
35. OFDM transmitters: analog representation and dft-based implementation
- Author
-
See-May Phoong and Yuan-Pei Lin
- Subjects
Theoretical computer science ,DFT matrix ,Computer science ,Orthogonal frequency-division multiplexing ,ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS ,Window (computing) ,Data_CODINGANDINFORMATIONTHEORY ,Pulse shaping ,Signal Processing ,Computer Science::Networking and Internet Architecture ,Electronic engineering ,Electrical and Electronic Engineering ,Representation (mathematics) ,Computer Science::Information Theory - Abstract
The implementation of orthogonal frequency division multiplexing (OFDM) transmitters typically consists of a discrete DFT matrix and a digital-to-analog (DAC) converter. Many existing results on the analysis of OFDM systems, e.g., spectral roll-off, are based on a convenient analog representation. We show that the analog representation and the DFT-based OFDM transmitters are equivalent only in special cases. Using the analog system to analyze the DFT-based OFDM system may not be valid if there is no equivalent analog representation.
- Published
- 2003
36. BER minimized OFDM systems with channel independent precoders
- Author
-
Yuan-Pei Lin and See-May Phoong
- Subjects
Minimum mean square error ,DFT matrix ,Orthogonal frequency-division multiplexing ,Frequency-division multiplexing ,Cyclic prefix ,Computer Science::Performance ,Control theory ,Signal Processing ,Computer Science::Networking and Internet Architecture ,Bit error rate ,Electrical and Electronic Engineering ,Algorithm ,Hadamard matrix ,Computer Science::Information Theory ,Mathematics ,Phase-shift keying - Abstract
We consider the minimization of uncoded bit error rate (BER) for the orthogonal frequency division multiplexing (OFDM) system with an orthogonal precoder. We analyze the BER performance of precoded OFDM systems with zero forcing and minimum mean squared error (MMSE) receivers. In the case of MMSE receivers, we show that for quadrature phase shift keying (QPSK), there exists a class of optimal precoders that are channel independent. Examples of this class include the discrete Fourier transform (DFT) matrix and the Hadamard matrix. When the precoder is the DFT matrix, the resulting optimal transceiver becomes the single carrier system with cyclic prefix (SC-CP) system. We also show that the worst solution corresponds to the conventional OFDM system; the conventional OFDM system has the largest BER. In the case of zero forcing receivers, the design of optimal transceiver depends on the signal-to-noise ratio (SNR). For higher SNR, solutions of optimal precoders are the same as those of MMSE receivers.
- Published
- 2003
37. Lapped unimodular transform and its factorization
- Author
-
Yuan-Pei Lin and See-May Phoong
- Subjects
Algebra ,Polynomial ,Matrix (mathematics) ,Unimodular matrix ,Factorization ,Finite impulse response ,Biorthogonal system ,Signal Processing ,Lapped transform ,Electrical and Electronic Engineering ,Matrix decomposition ,Mathematics - Abstract
Two types of lapped transforms have been studied in detail in the literature, namely, the lapped orthogonal transform (LOT) and its extension, the biorthogonal lapped transform (BOLT). In this paper, we will study the lapped unimodular transform (LUT). All three transforms are first-order matrices with finite impulse response (FIR) inverses. We will show that like LOT and BOLT, all LUTs can be factorized into degree-one unimodular matrices. The factorization is both minimal and complete. We will also show that all first-order systems with FIR inverses can be minimally factorized as a cascade of degree-one LOT, BOLT, and LUT building blocks. Two examples will be given to demonstrate that despite having a very small system delay, the LUTs have a satisfactory performance in comparison with LOT and BOLT.
- Published
- 2002
38. Minimum redundancy for ISI free FIR filterbank transceivers
- Author
-
See-May Phoong and Yuan-Pei Lin
- Subjects
Equalization ,Finite impulse response ,Orthogonal frequency-division multiplexing ,Computer science ,Bandwidth (signal processing) ,Equalization (audio) ,Filter bank ,Intersymbol interference ,Redundancy (information theory) ,Single antenna interference cancellation ,Control theory ,Signal Processing ,Electronic engineering ,Redundancy (engineering) ,Hardware_ARITHMETICANDLOGICSTRUCTURES ,Electrical and Electronic Engineering ,Computer Science::Information Theory ,Communication channel - Abstract
There has been great interest in the design of filterbank transceivers. Usually, with proper time domain equalization, the channel is modeled as an FIR filter. It is known that for FIR channels, the introduction of certain redundancy allows the receiver to cancel intersymbol interference (ISI) completely, and channel equalization is performed implicitly using FIR transceivers. This scheme allows us to trade bandwidth for ISI cancellation. In this paper, we derive the minimum redundancy required for the existence of FIR transceivers for a given channel. We see that the minimum redundancy is directly related to the zeros of the channel and to the Smith form of an appropriately defined channel matrix.
- Published
- 2002
39. Optimal ISI-free DMT transceivers for distorted channels with colored noise
- Author
-
See-May Phoong and Yuan-Pei Lin
- Subjects
Computer science ,business.industry ,Transmitter ,Topology ,Intersymbol interference ,Transmission (telecommunications) ,Modulation ,Colors of noise ,Signal Processing ,Electrical and Electronic Engineering ,Transceiver ,Telecommunications ,business ,Block (data storage) ,Communication channel - Abstract
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, where the transmitter and the receiver consist of constant matrices. Two types of block- based DMT transceivers are considered: the DMT system with zero padding (ZP-DMT) and the DMT system with general prefix (GP-DMT). We derive the bit allocation formula. For a given channel and channel noise spectrum, we design the ISI-free optimal transceiver that minimizes the transmission power for a given transmission rate and probability of error. For both ZP-DMT and GP-DMT systems, the optimal ISI-free transceiver can be given in closed from. We will see that for both classes, the optimal transceiver has an orthogonal transmitter. Simulation shows that the optimal DMT system can achieve the same transmission rate and the same probability of error with a much lower transmission power compared with other existing DMT systems.
- Published
- 2001
40. ISI-free FIR filterbank transceivers for frequency-selective channels
- Author
-
Yuan-Pei Lin and See-May Phoong
- Subjects
Signal processing ,Finite impulse response ,Frequency band ,Computer science ,Attenuation ,Equalization (audio) ,Stopband ,Filter bank ,Intersymbol interference ,Wavelet ,Control theory ,Modulation ,Signal Processing ,Electronic engineering ,Electrical and Electronic Engineering ,Network synthesis filters ,Transceiver ,Digital filter ,Data transmission - Abstract
Discrete multitone modulation transceivers (DMTs) have been shown to be very useful 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 transmitting and receiving filters. The receiving filters with good stopband attenuation are also desired for combating narrowband noise. The filterbank transceiver or discrete wavelet multitone (DWMT) system has been proposed as an implementation of the DMT transceiver that has better frequency band separation, but usually, intersymbol interference (ISI) cannot be completely cancelled in these filterbank transceivers, and additional equalization is required. We show how to use over interpolated filterbanks to design ISI-free FIR transceivers. A finite impulse response (FIR) transceiver with good frequency selectivity can be designed, as demonstrated by the design examples.
- Published
- 2001
41. Prediction-based lower triangular transform
- Author
-
Yuan-Pei Lin and See-May Phoong
- Subjects
Lossless compression ,Theoretical computer science ,Signal Processing ,Triangular matrix ,Signal compression ,Electrical and Electronic Engineering ,Lossy compression ,Decorrelation ,Algorithm ,Transform coding ,Sub-band coding ,Mathematics ,Data compression - Abstract
A new nonunitary transform called the prediction-based lower triangular transform (PLT) is introduced for signal compression. The new transform has the same decorrelation property as the Kahurnen-Loeve transform (KLT), but its implementational cost is less than one half of KLT. Compared with the KLT, the design cost of an M/spl times/M PLT is much lower and is only of the order of O(M/sup 2/). Moreover, the PLT can be factorized into simple building blocks. Using two different factorizations, we introduce two minimum noise structures that have roughly the same complexity as the direct implementation of PLT. These minimum noise structures have the following properties: (1) its noise gain is unity even though the transform is nonunitary; (2) perfect reconstruction is structurally guaranteed; (3) it can be used for both lossy/lossless compression. We show that the coding gain of PLT implemented using the minimum noise structure is the same as that of KLT. Furthermore, universal transform coders using PLT are derived. For AR(1) process, the M/spl times/M PLT has a closed form and needs only (M-1) multiplications and additions.
- Published
- 2000
42. Perfect discrete multitone modulation with optimal transceivers
- Author
-
See-May Phoong and Yuan-Pei Lin
- Subjects
Imagination ,media_common.quotation_subject ,Unitary matrix ,Topology ,Noise (electronics) ,Discrete Fourier transform ,Colors of noise ,Control theory ,Signal Processing ,Modulation (music) ,Moderate number ,Electrical and Electronic Engineering ,Transceiver ,Computer Science::Information Theory ,media_common ,Mathematics - Abstract
Previously, discrete Fourier transform (DFT)-based discrete multitone modulation (DMT) systems have been widely applied to various applications. In this paper, we study a broader class of DMT systems using more general unitary matrices instead of DFT matrices. For this class, we show how to design optimal DMT systems over frequency-selective channels with colored noise. In addition, asymptotical performance of DFT-based and optimal DMT systems are studied and shown to be equivalent. However, for a moderate number of bands, the optimal DMT system offers significant gain over the DFT-based DMT system, as is demonstrated by examples.
- Published
- 2000
43. MINLAB: minimum noise structure for ladder-based biorthogonal filter banks
- Author
-
See-May Phoong and Yuan-Pei Lin
- Subjects
Biorthogonal system ,Quantization (signal processing) ,Speech recognition ,Signal Processing ,Orthonormal basis ,Electrical and Electronic Engineering ,Filter bank ,Decorrelation ,Algorithm ,Coding gain ,Active noise control ,Mathematics ,Sub-band coding - Abstract
We introduce a minimum noise structure for ladder-based biorthogonal (MINLAB) filter bank. The minimum noise structure ensures that the quantization error has a unity noise gain, even though the filter bank is biorthogonal. The coder has a very low design and implementation cost. The perfect reconstruction property is structurally preserved. Optimal bit allocation and coding gain formulas are derived. We show that the coding gain of the optimal MINLAB coder is always greater than or equal to unity. For both AR(1) process and MA(1) process, the MINLAB coder with two taps has a higher coding gain than the optimal orthonormal coder with an infinite number of taps. In addition to its superior decorrelation ability, it has many other desired features that make it a potentially valuable and attractive alternative to the orthonormal coder, especially for a high-fidelity compression.
- Published
- 2000
44. Theory and design of two-parallelogram filter banks
- Author
-
Yuan-Pei Lin and P.P. Vaidyanathan
- Subjects
Voltage-controlled filter ,Computer science ,Stopband ,Topology ,Chebyshev filter ,Composite image filter ,Band-pass filter ,Control theory ,Orthonormal basis ,Electrical and Electronic Engineering ,Passband ,Active filter ,m-derived filter ,Half-band filter ,Signal processing ,Signal reconstruction ,Attenuation ,Electronic filter topology ,Butterworth filter ,Filter bank ,Constant k filter ,Adaptive filter ,Filter design ,Modulation ,Signal Processing ,Prototype filter ,Network synthesis filters ,Caltech Library Services ,Root-raised-cosine filter - Abstract
It is well known that the analysis and synthesis filters of orthonormal DFT filter banks can not have good frequency selectivity. The reason for this is that each of the analysis and synthesis filters have only one passband. Such frequency stacking (or configuration) in general does not allow alias cancellation when the individual filters have good stopband attenuation. A frequency stacking of this nature is called nonpermissible and should be avoided if good filters are desired. In a usual M-channel filter bank with real-coefficient filters, the analysis and synthesis filters have two passbands. It can be shown that the configuration is permissible in this case. Many designs proposed in the past demonstrate that filter banks with such configurations can have perfect reconstruction and be good filters at the same time. We develop the two-parallelogram filter banks, which is the class of 2-D filter banks in which the supports of the analysis and synthesis filters consist of two parallelograms. The two-parallelogram filter banks are analyzed from a pictorial viewpoint by exploiting the concept of permissibility. Based on this analysis, we construct and design a special type of two-parallelogram filter banks, namely, cosine-modulated filter banks (CMFB). In two-parallelogram CMFB, the analysis and synthesis filters are cosine-modulated versions of a prototype that has a parallelogram support. Necessary and sufficient conditions for perfect reconstruction of two-parallelogram CMFB are derived.
- Published
- 1996
45. Linear phase cosine modulated maximally decimated filter banks with perfect reconstruction
- Author
-
Yuan-Pei Lin and P.P. Vaidyanathan
- Subjects
Engineering ,Finite impulse response ,business.industry ,Bandwidth (signal processing) ,Filter bank ,Coding gain ,Band-pass filter ,Control theory ,Filter (video) ,Signal Processing ,Prototype filter ,Electrical and Electronic Engineering ,business ,Digital filter ,Passband ,Algorithm ,Caltech Library Services ,Linear phase ,Root-raised-cosine filter ,Mathematics - Abstract
We propose a novel way to design maximally decimated FIR cosine modulated filter banks, in which each analysis and synthesis filter has a linear phase. The system can be designed to have either the approximate reconstruction property (pseudo-QMF system) or perfect reconstruction property (PR system). In the PR case, the system is a paraunitary filter bank. As in earlier work on cosine modulated systems, all the analysis filters come from an FIR prototype filter. However, unlike in any of the previous designs, all but two of the analysis filters have a total bandwidth of 2/spl pi//M rather than /spl pi//M (where 2M is the number of channels in our notation). A simple interpretation is possible in terms of the complex (hypothetical) analytic signal corresponding to each bandpass subband. The coding gain of the new system is comparable with that of a traditional M-channel system (rather than a 2M-channel system). This is primarily because there are typically two bandpass filters with the same passband support. Correspondingly, the cost of the system (in terms of complexity of implementation) is also comparable with that of an M-channel system. We also demonstrate that very good attenuation characteristics can be obtained with the new system.
- Published
- 1995
46. Predictive Coding of Bit Loading for Time-Correlated MIMO Channels With a Decision Feedback Receiver.
- Author
-
Li, Chien-Chang and Lin, Yuan-Pei
- Subjects
MIMO systems ,ELECTRONIC feedback ,MARKOV processes ,RADIO transmitter fading ,SIGNAL-to-noise ratio - Abstract
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. [ABSTRACT FROM PUBLISHER]
- Published
- 2015
- Full Text
- View/download PDF
47. Variable-Rate Transmission for MIMO Time-Correlated Channels With Limited Feedback.
- Author
-
Lin, Yuan-Pei
- Subjects
MIMO systems ,ELECTRONIC feedback ,ERROR rates ,DATA packeting ,BLOCK codes - Abstract
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 propose to feedback bit loading using predictive coding, which is known to be a powerful quantization technique when the underlying signal is correlated in time. Assuming the channel is a first-order Gauss-Markov random process, we derive the predictor for the bit loading to be coded and analyze the corresponding prediction error variance when the channel is varying slowly. By exploiting the prediction error variance, we adapt the quantizer of the prediction error to have a smaller quantization error. Furthermore we show that the prediction error variance is proportional to a term that depends only on the time-correlation coefficient. This leads to the conclusion that, a codebook that is designed for a particular time correlation coefficient can be easily modified to a codebook for a different correlation coefficient without redesign. Simulations are presented to demonstrate that the proposed predictive coding can achieve a very good approximation of the desired transmission rate with a very low feedback rate. [ABSTRACT FROM PUBLISHER]
- Published
- 2014
- Full Text
- View/download PDF
48. Limited Feedback of Precoder and Bit Loading for MIMO Systems: A Joint Design
- Author
-
Chen, Hung-Chun, primary and Lin, Yuan-Pei, additional
- Published
- 2013
- Full Text
- View/download PDF
49. Lattice Quantization of Phases for Equal Gain Transmission.
- Author
-
Tsai, Shang-Ho and Lin, Yuan-Pei
- Subjects
SIGNAL processing mathematics ,LATTICE theory ,DISTRIBUTIVE lattices ,SIGNAL-to-noise ratio ,MEAN square algorithms - Abstract
Equal gain transmission (EGT) requires only the feedback of phase information and is known to enjoy several implementational advantages compared to maximum ratio transmission (MRT). This paper investigates the use of lattice quantization for quantizing phases in EGT systems. In practice, the feedback rate is finite and the lattices need to be truncated to have finite code rate. The truncation of lattices results in boundary effect; hence, earlier results developed for untruncated lattices, e.g., fast algorithm and mean-square error (MSE) analysis, cannot be applied directly. Exploiting the fact that the quantized signals are phases, we show how to quantize using truncated lattices so that there is no boundary effect. Moreover, we propose efficient methods to convert between lattice codewords and binary digits so that the lattice quantization can be used in practical systems. Furthermore, the mean-square quantization error is analyzed for several useful truncated lattices. We also show how to analyze the signal-to-noise ratio (SNR) loss when the proposed quantization is applied to an EGT system. [ABSTRACT FROM PUBLISHER]
- Published
- 2012
- Full Text
- View/download PDF
50. On the Duality of MIMO Transceiver Designs With Bit Allocation.
- Author
-
Li, Chien-Chang and Lin, Yuan-Pei
- Subjects
DUALITY theory (Mathematics) ,MIMO systems ,RADIO transmitter-receivers ,BIT rate ,RESOURCE allocation ,LITERATURE reviews ,CONSTRAINT satisfaction ,SIMULATION methods & models - Abstract
Bit rate and power are two commonly used optimality criteria for MIMO transceiver design. In the literature, bit rate maximization and power minimization problems are viewed as different problems and solved independently. In this paper, we derive the duality between these two problems for both the cases with and without integer constraint on bit allocation. We will show that if a transceiver is optimal for the power-minimizing problem, it is also optimal for the rate maximizing problem, and the converse is true. Such a duality has not been stated and proved in the literature to the best of our knowledge. The derivation does not involve any existing optimal solution and we can establish duality result even for the rate maximization problem with integer bit constraint, which the optimal solution is not known. The duality also allows us to develop an algorithm for finding the rate-maximizing transceiver with integer bit allocation using the solution of power-minimizing system. We will also consider some possible generalizations of the problem, for example, when there is a constraint on the maximal constellation size and when the subchannel bit error rates (BERs) are constrained. For each of these cases, we will see that the duality between the two problems continued to hold. In the simulations, we will compute the optimal solutions for these two problems and demonstrate the duality between these two. [ABSTRACT FROM PUBLISHER]
- Published
- 2011
- Full Text
- View/download PDF
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