Browsing by Author "Lin, TT"

Now showing 1 - 9 of 9

A novel two-stage channel estimation method for wireless communications
(2004-06-01)
Lin, WJ
;
Lin, TT
;
Huang, CC
;
電信工程研究所
;
Institute of Communications Engineering
In this paper, we proposed a novel two-stage channel estimation (2S-CE) method. In contrast to conventional channel estimation methods, this method makes the maximum use of the information contributed by the known data in every transmission burst. In the first stage, the least-squares (LS) algorithm was used to estimate the channel impulse response (CIR) based on the normal training sequence. Then the maximum channel memory was estimated and used to locate the uncorrupted data in the guard interval. In the second stage, the uncorrupted data together with the normal training sequence were sent to the LS algorithm again to obtain the fine-tuned CIR. To verify the efficiency of the proposed 2S-CE method, both a theoretical analysis and computer simulations have been done. Computer simulation results confirm the analysis results and demonstrate that the proposed 2S-CE method outperforms a conventional single-stage channel estimation method.
Adaptive beamforming with interpolated arrays for multiple coherent interferers
(1997-03-01)
Lee, TS
;
Lin, TT
;
交大名義發表
;
電信工程研究所
;
National Chiao Tung University
The spatial smoothing technique is effective in decorrelating multiple coherent interferers for an adaptive beamformer. However, it requires a configuration with identical subarrays. This paper presents an interpolation scheme to synthesize multiple virtual subarrays allowing for the use of spatial smoothing from a real array of arbitrary geometry. After interpolation, the optimum spatially smoothed subarray beamformer is constructed. A dimension recovery transformation can then be implemented to calculate the weights of the full array which will retain the interference nulls of the subarray beamformer. The efficacy of the proposed scheme is assessed through simulation. (C) 1997 Elsevier Science B.V.
Adaptive beamforming with interpolated arrays for multiple coherent interferers
(1997-03-01)
Lee, TS
;
Lin, TT
;
電信工程研究所
;
Institute of Communications Engineering
The spatial smoothing technique is effective in decorrelating multiple coherent interferers for an adaptive beamformer. However, it requires a configuration with identical subarrays. This paper presents an interpolation scheme to synthesize multiple virtual subarrays allowing for the use of spatial smoothing from a real array of arbitrary geometry. After interpolation, the optimum spatially smoothed subarray beamformer is constructed. A dimension recovery transformation can then be implemented to calculate the weights of the full array which will retain the interference nulls of the subarray beamformer. The efficacy of the proposed scheme is assessed through simulation. (C) 1997 Elsevier Science B.V.
Coherent interference suppression with complementally transformed adaptive beamformer
(1998-05-01)
Lee, TS
;
Lin, TT
;
電信工程研究所
;
Institute of Communications Engineering
This paper proposes a beamforming scheme for suppressing coherent interference with an array of arbitrary geometry. The scheme first uses estimates of the source directions to construct a transformation, which removes the desired signal while retaining the coherent interference. Optimum beamforming is then performed on the transformed data containing only interference and noise to produce the maximum output signal-to-interference-plus-noise ratio (SINR), Analysis and numerical results demonstrate that the proposed complementally transformed beamformer significantly outperforms the conventional multiply constrained minimum variance (MCMV) beamformers.
Design of partially adaptive STBC CDMA receiver using conjugate gradient algorithm
(2004)
Lin, GJ
;
Lin, TT
;
Lee, TS
;
電信工程研究所
;
Institute of Communications Engineering
A novel partially adaptive (PA) receiver with MAI suppression is proposed for an STBC CDMA system under the multipath fading channels. A low-complexity PA realization of the receiver is developed based on the generalized sidelobe canceller (GSC) technique which partial adaptivity is incorporated via the conjugate gradient (CG) algorithm for reduced complexity implementation. The proposed PA receiver is evaluated through simulations, and the results show that it can achieve nearly the same performance of the conventional fully adaptive MMSE receiver by using a small number of pilot symbols.
Design of pattern diversity antenna for mobile communications
(1996)
Lee, TS
;
Chen, CT
;
Lin, TT
;
電信工程研究所
;
Institute of Communications Engineering
Development and analysis of a two-stage beamformer for multiple correlated interferers using rectangular array
(1999-01-01)
Lin, TT
;
Lee, TS
;
電信工程研究所
;
Institute of Communications Engineering
A two-stage two-dimensional (2-D) beamformer is proposed for signal enhancement in an environment of multiple correlated interferers using a rectangular array. In the first stage, subarray beamformers are constructed which exhibit reliable interference cancellation using difference preprocessed and spatially smoothed data. A secondary combining of all possible subarray beamformers is then performed to fully exploit the array aperture. It is shown that, compared to the conventional one-stage optimum beamformer, the two-stage beamformer performs equally well and requires a much lower complexity of implementation when a suitable subarray size is chosen. (C) 1999 Acoustical Society of America. [S0001-4966(99)04701-3].
Development and analysis of a two-stage beamformer for multiple correlated interferers using rectangular array
(1999-01-01)
Lin, TT
;
Lee, TS
;
電信工程研究所
;
Institute of Communications Engineering
A two-stage two-dimensional (2-D) beamformer is proposed for signal enhancement in an environment of multiple correlated interferers using a rectangular array. In the first stage, subarray beamformers are constructed which exhibit reliable interference cancellation using difference preprocessed and spatially smoothed data. A secondary combining of all possible subarray beamformers is then performed to fully exploit the array aperture. It is shown that, compared to the conventional one-stage optimum beamformer, the two-stage beamformer performs equally well and requires a much lower complexity of implementation when a suitable subarray size is chosen. (C) 1999 Acoustical Society of America. [S0001-4966(99)04701-3].
Reception of coherent signals with steering vector restoral beamformer
(1999-02-01)
Lee, TS
;
Lin, TT
;
電信工程研究所
;
Institute of Communications Engineering
A beamforming scheme is proposed for reception of multiple coherent signals. The scheme consists of three stages. First, estimates of coherent source directions are used to restore the composite steering vector (CSV). Second, a transformation removes the coherent signals with the interference and noise retained. Finally, optimum beamforming is performed based on the CSV and transformed data to produce the maximum output signal-to-interference-plus-noise ratio (SINR). Numerical examples confirm the efficacy of the proposed beamformer in combining the coherent signals. (C) 1999 Elsevier Science B.V. All rights reserved.