Browsing by Author "Huang, Chung-Jung"

Now showing 1 - 9 of 9

A closed-form phase-comparison ML DOA estimator for automotive radar with one single snapshot
(2013)
Huang, Chung-Jung
;
Dai, Chia-Wei
;
Tsai, Tsung-Yu
;
Chung, Wei-Ho
;
Lee, Ta-Sung
In automotive radar systems, only a small number of snapshots are available for direction-of-arrival (DOA) estimation in high mobility scenarios. We here propose a closed-form single-snapshot maximum likelihood (ML) DOA estimator based on the phase-comparison technique. The estimator can be effective in a wide field-of-view (FOV) scenario and is robust to gain-mismatch effects among antenna elements. Computer simulations are conducted to confirm the effectiveness of the proposed method.
A geometry based efficient decoder for underdetermined MIMO systems
(2015-06-01)
Huang, Chung-Jung
;
Lee, Chang-Shen
;
Chung, Wei-Ho
;
Lee, Ta-Sung
;
電機資訊學士班
In this paper, a geometry based decoder with low decoding complexity and exact maximum-likelihood (ML) performance is proposed for underdetermined multiple-input multiple-output (MIMO) systems. In the proposed decoder, an underdetermined MIMO system can be divided into a multiple-input single-output (MISO) sub-system and a regular MIMO sub-system in which numbers of transmit and receive antennas are equal. An efficient slab search algorithm (ESSA) is adopted to efficiently obtain valid candidate points in the MISO sub-system. By adopting ESSA in the MISO sub-system and sphere decoding algorithm (SDA) in the MIMO sub-system, ML solution of underdetermined MIMO system can be obtained with low computational complexity. To further reduce the computational complexity, a near-ML SDA is proposed to more efficiently find the candidate points in the MIMO sub-system. In addition, an optimal preprocessing technique is proposed from the geometrical perspective and the comprehensive analysis on the complexity reduction is also provided. Simulation results indicate that the proposed approach significantly reduces the complexity as compared to existing ML decoders, particularly for systems with large number of antennas and/or high-order constellations. (C) 2015 Elsevier Inc. All rights reserved.
A Low Complexity Configuration Selection Algorithm in IA-aided Uplink Coordinated Multipoint Systems
(2014-01-01)
Lee, Ming-Chun
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Huang, Chung-Jung
;
Chung, Wei-Ho
;
Lee, Ta-Sung
;
電機資訊學士班
This work investigates the configuration selection in IA-aided UL CoMP systems which pursues the maximal achievable sum rate. The configuration is defined by the number of data streams transmitted in each user. Intuitively, the solution can be found by exhaustively calculating the achievable sum rate for all the possible configurations, and select the configuration leading to the maximal achievable sum rate. The exhaustive search method is infeasible due to its high complexity. Based on the characteristics of IA-aided UL CoMP systems, an algorithm is proposed to obtain the configuration with extremely low complexity, and the proposed approach achieves comparable performance as in exhaustive method.
Codebook Based Interference Alignment in Uplink Coordinated Multipoint Systems
(2012)
Huang, Chung-Jung
;
Chang, Wei-Che
;
Lee, Ta-Sung
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電機工程學系
;
Department of Electrical and Computer Engineering
Interference alignment (IA) in uplink coordinated multipoint (CoMP) has been proved to be able to improve the performance in next generation mobile cellular systems. In this paper, an efficient codebook-based Max-SINR IA aided uplink (UL) CoMP scheme with full cooperation at the receiver is proposed. Compared to conventional IA, codebook-based IA requires less feedback information and maintains the same significant improvement in system capacity. To avoid the exhaustive precoder search in codebook-based IA, the K-Best selection algorithm is adopted to efficiently perform precoder selection. Simulation results demonstrate that the proposed codebook-based IA and K-Best precoder selection algorithm can achieve a significant performance gain especially in severe interference environments.
Efficient Interference Alignment Aided Transceiver Design for LTE-A Uplink Coordinated Multipoint Systems
(2013-01-01)
Huang, Chung-Jung
;
Chung, Gang-Han
;
Chung, Wei-Ho
;
Lee, Ta-Sung
;
電子工程學系及電子研究所
An efficient interference alignment (IA) aided transceiver design algorithm for uplink (UL) coordinated multipoint (CoMP) systems is proposed to mitigate interference. We use the block QR decomposition (BQRD) to resolve the interdependency of precoders among user equipment (UE) through the successive interference cancellation (SIC) technique. To further improve the efficiency, an additional constraint is employed by a projection operation. Simulation results show that the proposed algorithm substantially reduces iterations and obtain comparable performance as in conventional approaches.
GEOMETRY BASED EFFICIENT DECODING ALGORITHMS FOR UNDERDETERMINED MIMO SYSTEMS
(2011)
Huang, Chung-Jung
;
Wu, Chih-Yung
;
Lee, Ta-Sung
;
電機工程學系
;
Department of Electrical and Computer Engineering
In this paper, a novel decoder for underdetermined MIMO systems with low decoding complexity is proposed. The development of the proposed decoder consists of two stages. First, an improved slab decoding algorithm efficiently obtains all valid candidate points within a given slab. Next, a multi-slab based decoding algorithm finds the optimal solution by conducting intersections on the obtained candidate set with dynamic radius adaptation. The proposed decoder offers the advantages of low computational complexity and near-ML decoding performance for underdetermined MIMO systems. Simulation results indicate that it effectively reduces the complexity as compared to existing decoders, especially for large antenna numbers and/or constellations.
Linear transceiver design in uplink coordinated multipoint multiple-input multiple-output systems
(2014-11-27)
Lee, Ming-Chun
;
Chung, Wei-Ho
;
Huang, Chung-Jung
;
Chung, Gang-Han
;
Lee, Ta-Sung
The authors investigate linear transceiver design in uplink (UL) coordinated multipoint transmission and reception (CoMP) multiple-input multiple-output (MIMO) systems with joint detections. A two-stage design algorithm is proposed by exploiting the technique of interference alignment, optimising the structure of the effective channel and employing power loading, with the goal to achieve high throughput and convergence performance. In contrast to conventional CoMP transceiver design, which is investigated under a predefined number of data streams transmitted by each user, the authors further investigate the selection of the number of data streams, called the configuration selection, and propose a corresponding low-complexity algorithm. By combining the proposed linear transceiver algorithm and low-complexity configuration selection algorithm, this work presents a new practical framework for linear transceiver design in UL CoMP MIMO systems. The simulation results confirm that the proposed algorithms achieve higher sum-rate performance than prior linear transceivers used in UL CoMP MIMO systems. Furthermore, the proposed transceiver offers comparable performance to existing IA-aided transceivers with significantly faster convergence.
Method For Selecting Transmitting Points In A Communication System
(2011-01-13)
Huang, Chung-Jung
;
Sung, Chih-Sheng
;
Lee, Ta-Sung
The present invention provides a method for identifying a specific number of communicating points having relatively smallest accumulated path values from a plurality of transmitting points for a receiving point in a communication system. The method includes steps of: (a) defining a first coordination of each of the plurality of transmitting points and the receiving point on a complex plane; (b) transferring the first coordination of the receiving point to a second coordination thereof, in which the second coordination of the receiving point is near an origin of the complex plane; and (c) identifying the specific number of transmitting points having relatively smallest accumulated path values based on the second coordination of the receiving point.
Sectorization with Beam Pattern Design Using 3D Beamforming Techniques
(2013)
Lee, Chang-Shen
;
Lee, Ming-Chun
;
Huang, Chung-Jung
;
Lee, Ta-Sung
;
電機工程學系
This paper presents a framework for a three-dimensional (3D) beam pattern design with a load-balanced cell sectorization strategy. First, characteristics of the 3D beam pattern were observed, and convex optimization was used to provide a solution based on the criteria that describe the observations. In addition, a user equipment (UE) determination problem that arose because of cell sectorization was also addressed. By incorporating a beam pattern design with a proposed UE determination scheme, a framework of a backward compatible system was completed. The network performance regarding throughput for cell sectorization with a dedicated beam pattern design was evaluated and the simulation results show that the proposed system is superior compared to the conventional system and other proposed sectorization schemes.