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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal DOI :
Electronics and Telecommunications Research Institute
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Volume & Issues
Volume 26, Issue 6 - Dec 2004
Volume 26, Issue 5 - Oct 2004
Volume 26, Issue 4 - Aug 2004
Volume 26, Issue 3 - Jun 2004
Volume 26, Issue 2 - Apr 2004
Volume 26, Issue 1 - Feb 2004
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Independent Turbo Coding and Common Interleaving Method among Transmitter Branches Achieving Peak Throughput of 1 Gbps in OFCDM MIMO Multiplexing
Kawamoto, Junichiro ; Asai, Takahiro ; Higuchi, Kenichi ; Sawahashi, Mamoru ;
ETRI Journal, volume 26, issue 5, 2004, Pages 375~375
This paper proposes a common interleaving method associated with independent channel-encoding among transmitter antenna branches in orthogonal frequency and code division multiplexing based on multiple-input multiple-output (MIMO) multiplexing to achieve an extremely high throughput such as 1 Gbps using a 100 MHz bandwidth. This paper also investigates the average packet error rate performance as a function of the average received signal energy per bit-to-background noise power spectrum density ratio
. We found that the loss in the required average received
of the proposed method is only within approximately 0.3 dB in up to a 12-path Rayleigh fading channel, using 16QAM and Turbo coding with a coding rate of 5/6. We also clarify that even for a large fading correlation among antenna branches, 1 Gbps is still possible by increasing the transmission power. Therefore, the proposed method reduces the processing rate to 1/4 in the turbo decoder with only a slight loss in the required average received
Joint Processing of Zero-Forcing Detection and MAP Decoding for a MIMO-OFDM System
Sohn, In-Soo ; Ahn, Jae-Young ;
ETRI Journal, volume 26, issue 5, 2004, Pages 384~384
We propose a new bandwidth-efficient technique that achieves high data rates over a wideband wireless channel. This new scheme is targeted for a multiple-input multiple- output orthogonal frequency-division multiplexing (MIMO-OFDM) system that achieves transmit diversity through a space frequency block code and capacity enhancement through the iterative joint processing of zero-forcing detection and maximum a posteriori (MAP) decoding. Furthermore, the proposed scheme is compared to the coded Bell Labs Layered Space-Time OFDM (BLAST-OFDM) scheme.
Packet Loss Fair Scheduling Scheme for Real-Time Traffic in OFDMA Systems
Shin, Seok-Joo ; Ryu, Byung-Han ;
ETRI Journal, volume 26, issue 5, 2004, Pages 391~391
In this paper, we propose a packet scheduling discipline called packet loss fair scheduling, in which the packet loss of each user from different real-time traffic is fairly distributed according to the quality of service requirements. We consider an orthogonal frequency division multiple access (OFDMA) system. The basic frame structure of the system is for the downlink in a cellular packet network, where the time axis is divided into a finite number of slots within a frame, and the frequency axis is segmented into subchannels that consist of multiple subcarriers. In addition, to compensate for fast and slow channel variation, we employ a link adaptation technique such as adaptive modulation and coding. From the simulation results, our proposed packet scheduling scheme can support QoS differentiations while guaranteeing short-term fairness as well as long-term fairness for various real-time traffic.
Pilot Symbol Assisted Hybrid Detection for OFDM-Based Spatial Multiplexing Systems
So, Yoon-Jae ; Jeon, Hyoung-Goo ; You, Young-Hwan ; Baek, Myung-Sun ; Song, Hyoung-Kyu ;
ETRI Journal, volume 26, issue 5, 2004, Pages 397~397
In this paper, we provide a new detection scheme for a pilot symbol assisted interference nulling and cancellation operation to reduce unexpected effects owing to parallel transmission in orthogonal frequency division multiplexing (OFDM)-based spatial multiplexing systems. We have shown that the investigated OFDM vertical Bell laboratories layered space time (VBLAST) detection based on hybrid processing performs better than ordinary OFDM-VBLAST detections based on serial processing and parallel processing, respectively.
Application of Rate Compatible Punctured Turbo Coded Hybrid ARQ to MC-CDMA Mobile Radio
Garg, Deepshikha ; Adachi, Fumiyuki ;
ETRI Journal, volume 26, issue 5, 2004, Pages 405~405
MC-CDMA, a multicarrier (MC) modulation scheme based on code division multiple access (CDMA), is the most likely candidate for the next generation of mobile radio communications. The rate compatible punctured turbo (RCPT) coded hybrid automatic repeat request (HARQ) has been found to give improved throughput performance in a direct sequence (DS) CDMA system. However, the extent to which the RCPT HARQ improves the throughput performance of an MC-CDMA system has not been fully understood. In this paper, we apply the RCPT HARQ to MC-CDMA and evaluate by computer simulations its performance in a frequency selective Rayleigh fading channel. We found that the performance of RCPT HARQ MC-CDMA is almost insensitive to channel characteristics. The performance can be drastically improved with receive diversity combined with space-time transmit diversity. In addition, the comparison of RCPT HARQ MC-CDMA, orthogonal frequency division multiplexing, and DS-CDMA shows that under similar conditions the throughput of MC-CDMA is the best in a frequency selective fading channel.
Effects of Array Weight Errors on Parallel Interferene Cancellation Receiver in Uplink Synchronous and Asynchronous DS-CDMA Systems
Kim, Yong-Seok ; Hwang, Seung-Hoon ; Whang, Keum-Chan ;
ETRI Journal, volume 26, issue 5, 2004, Pages 413~413
This paper investigates the impacts of array weight errors (AWE) in an antenna array (AA) on a parallel interference cancellation (PIC) receiver in uplink synchronous and asynchronous direct sequence code division multiple access (DS-CDMA) systems. The performance degradation due to an AWE, which is approximated by a Gaussian distributed random variable, is estimated as a function of the variance of the AWE. Theoretical analysis, confirmed by simulation, demonstrates the tradeoffs encountered between system parameters such as the number of antennas and the variance of the AWE in terms of the achievable average bit error rate and the user capacity. Numerical results show that the performance of the PIC with the AA in the DS-CDMA uplink is sensitive to the AWE. However, either a larger number of antennas or uplink synchronous transmissions have the potential of reducing the overall sensitivity, and thus improving its performance.
A Unified Framework for Transmitter Power Control in Cellular Radio Systems
Chai, Chin Choy ; Lu, Ying ; Chew, Yong Huat ; Tjhung, Tjeng Thiang ;
ETRI Journal, volume 26, issue 5, 2004, Pages 423~423
In earlier works on transmitter power control in cellular radio systems, the problem of whether a signal-to-interference ratio (SIR) threshold is achievable is determined by apparently different rules for homogeneous and heterogeneous SIR systems. In this paper, we present a unified and more universal framework for both cases. We also highlight the conditions under which a given SIR threshold vector for the heterogeneous SIR system is achievable, although so far there is no general solution to this problem.
An Improvement of UMP-BP Decoding Algorithm Using the Minimum Mean Square Error Linear Estimator
Kim, Nam-Shik ; Kim, Jae-Bum ; Park, Hyun-Cheol ; Suh, Seung-Bum ;
ETRI Journal, volume 26, issue 5, 2004, Pages 432~432
In this paper, we propose the modified uniformly most powerful (UMP) belief-propagation (BP)-based decoding algorithm which utilizes multiplicative and additive factors to diminish the errors introduced by the approximation of the soft values given by a previously proposed UMP BP-based algorithm. This modified UMP BP-based algorithm shows better performance than that of the normalized UMP BP-based algorithm, i.e., it has an error performance closer to BP than that of the normalized UMP BP-based algorithm on the additive white Gaussian noise channel for low density parity check codes. Also, this algorithm has the same complexity in its implementation as the normalized UMP BP-based algorithm.
A Rule-Based Algorithm for Common Pilot Channel and Antenna Tilt Optimization in UMTS FDD Networks
Gerdenitsch, Alexander ; Jakl, Stefan ; Chong, Yee-Yang ; Toeltsch, Martin ;
ETRI Journal, volume 26, issue 5, 2004, Pages 437~437
In this paper we address the problem of capacity optimization in a Universal Mobile Telecommunication System (UMTS) radio network. We present an optimization algorithm for finding the best settings of the antenna tilt and common pilot channel power of the base stations. This algorithm is a parametric method, based on a set of rules. We evaluated our optimization technique on a virtual network scenario with 75 cells. For this scenario we show an increase in capacity compared to the initial settings of about 60 percent.
Adaptive Channel-Matched Extended Alamouti Space-Time Code Exploiting Partial Feedback
Badic, Biljana ; Rupp, Markus ; Weinrichter, Hans ;
ETRI Journal, volume 26, issue 5, 2004, Pages 443~443
Since the publication of Alamouti's famous space-time block code, various quasi-orthogonal space-time block codes (QSTBC) for multi-input multi-output (MIMO) fading channels for more than two transmit antennas have been proposed. It has been shown that these codes cannot achieve full diversity at full rate. In this paper, we present a simple feedback scheme for rich scattering (flat Rayleigh fading) MIMO channels that improves the coding gain and diversity of a QSTBC for 2
) transmit antennas. The relevant channel state information is sent back from the receiver to the transmitter quantized to one or two bits per code block. In this way, signal transmission with an improved coding gain and diversity near to the maximum diversity order is achieved. Such high diversity can be exploited with either a maximum-likelihood receiver or low-complexity zero-forcing receiver.
Metadata Broadcasting for Personalized Service: A Practical Solution
Kang, Kyeong-Ok ; Kim, Jae-Gon ; Lee, Hee-Kyung ; Chang, Hyun-Sung ; Yang, Seung-Jun ; Kim, Young-Tae ; Lee, Han-Kyu ; Kim, Jin-Woong ;
ETRI Journal, volume 26, issue 5, 2004, Pages 452~452
DOI : 10.4218/etrij.04.0603.0011
As the number of broadcasting channels and programs increases rapidly, the importance of personalized service has been emphasized. In this paper, we propose a practical framework of metadata broadcasting to provide personalized service according to user preferences and various terminal/network conditions. First, we present an overall system architecture of a metadata broadcasting system and then propose several core technologies (particularly in the parts of metadata authoring, metadata encoding, and metadata-based personalized content consumption). For interoperability, the proposed solution is designed to be compliant with the relevant standards of the TV-Anytime Forum, MPEG-7 Systems, and MPEG-2 Systems. Considering a home network environment, we also propose a metadata-based content adaptation scheme. Each component technology has been implemented individually, integrated into an end-to-end prototype broadcasting system, and successfully tested with a set of personalized service scenarios that are also developed in this study.
Effect of Antenna Aperture Field on Co-channel Interference, Capacity, and Payload Mass in High Altitude Platform Communications
Thornton, John ; Grace, David ;
ETRI Journal, volume 26, issue 5, 2004, Pages 467~467
In a High Altitude Platform (HAP) cellular communications network, each cell may be served by a dedicated spot-beam antenna. The antennas' beam properties and their spatial overlap control the co-channel interference. In prior literature, radiation patterns have been approximated by a main lobe followed by a constant sidelobe floor. A network of 121 cells has been studied and the method is here extended to the use of more realistic radiation patterns based on the theoretical aperture antenna patterns. This allows for the comparison of the effect of different aperture field tapers, which lead to reduced sidelobe levels and hence higher system capacity but also a more massive antenna payload.
Self-Assembled InAs Quantum Dots on InP(001) for Long-Wavelength Laser Applications
Kim, Jin-Soo ; Lee, Jin-Hong ; Hong, Sung-Ui ; Kwack, Ho-Sang ; Lee, Chul-Wook ; Oh, Dae-Kon ;
ETRI Journal, volume 26, issue 5, 2004, Pages 475~475
Self-assembled InAs quantum dots (QDs) embedded in an InAlGaAs matrix were grown on an InP (001) using a solid-source molecular beam epitaxy and investigated using transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. TEM images indicated that the QD formation was strongly dependent on the growth behaviors of group III elements during the deposition of InAlGaAs barriers. We achieved a lasing operation of around 1.5
at room temperature from uncoated QD lasers based on the InAlGaAs-InAlAs material system on the InP (001). The lasing wavelengths of the ridge-waveguide QD lasers were also dependent upon the cavity lengths due mainly to the gain required for the lasing operation.
Radiation From a Current Filament Located inside a Cylindrical Frequency Selective Surface
Uzer, Ali ; Ege, Tuncay ;
ETRI Journal, volume 26, issue 5, 2004, Pages 481~481
We consider electromagnetic field radiation properties of a current filament placed at the origin of a cylindrical frequency selective surface (CFSS). The CFSS consists of free standing metal strips with two-dimensional periodicity. The analysis is based on a cylindrical Floquet mode wave expansion technique. We observed that near the half wavelength resonance frequencies, there exist some specific frequencies at which the surface becomes totally transparent.
A Highly Linear CMOS Baseband Chain for Wideband Wireless Applications
Yoo, Seoung-Jae ; Ismail, Mohammed ;
ETRI Journal, volume 26, issue 5, 2004, Pages 486~486
The emergence of wide channel bandwidth wireless standards requires the use of a highly linear, wideband integrated CMOS baseband chain with moderate power consumption. In this paper, we present the design of highly linear, wideband active RC filters and a digitally programmable variable gain amplifier. To achieve a high unity gain bandwidth product with moderate power consumption, the feed-forward compensation technique is applied for the design of wideband active RC filters. Measured results from a
CMOS prototype baseband chain show a cutoff frequency of 10 MHz, a variable gain range of 33 dB, an in-band IIP3 of 13 dBV, and an input referred noise of 114
while dissipating 20 mW from a 3 V supply.
An Efficient Two-Step Paging Strategy Using Base Station Paging Agents in Mobile Communication Networks
Baek, Jang-Hyun ; Ryu, Byung-Han ;
ETRI Journal, volume 26, issue 5, 2004, Pages 493~493
An effective paging strategy is essential for improving the utility of radio channels. This paper proposes a two-step paging strategy which involves using base station paging agents to page a single cell at each paging. An analytical model is used to evaluate the performance of the proposed strategy. The proposed strategy is compared with the traditional simultaneous paging strategy and a recent proposal using the base station paging agents. The numerical results showed that the proposed strategy proficiently reduces paging cost on radio channels compared with other paging strategies.
A Bimodal Approach for Land Vehicle Localization
Kim, Seong-Baek ; Choi, Kyung-Ho ; Lee, Seung-Yong ; Choi, Ji-Hoon ; Hwang, Tae-Hyun ; Jang, Byung-Tae ; Lee, Jong-Hun ;
ETRI Journal, volume 26, issue 5, 2004, Pages 497~497
In this paper, we present a novel idea to integrate a low cost inertial measurement unit (IMU) and Global Positioning System (GPS) for land vehicle localization. By taking advantage of positioning data calculated from an image based on photogrammetry and stereo-vision techniques, errors caused by a GPS outage for land vehicle localization were significantly reduced in the proposed bimodal approach. More specifically, positioning data from the photogrammetric approach are fed back into the Kalman filter to reduce and compensate for IMU errors and improve the performance. Experimental results are presented to show the robustness of the proposed method, which can be used to reduce positioning errors caused by a low cost IMU when a GPS signal is not available in urban areas.
A Joint Scheme of AGC and Gain/Phase Mismatch Compensation for QPSK DCR
Song, Yun-Jeong ; Lee, Ho-Jin ; Ra, Sung-Woong ; Kim, Young-Wan ;
ETRI Journal, volume 26, issue 5, 2004, Pages 501~501
This paper presents a simple gain/phase blind compensation algorithm with an automatic gain control (AGC) function for the adoption of the AGC function and compensation for gain/phase imbalances in quadrature phase shift keying (QPSK) direct conversion receivers (DCRs). The AGC function is interactively operated with the compensation algorithm for gain/phase imbalances. By detecting the gain sum and difference values between the I-channel and Q-channel, the combined AGC and gain imbalance compensation algorithm provides a simpler DCR architecture.
Exhaustive Output Arbitration of Input Buffered Switch with Buffered Crossbar
Yoon, Bin-Yeong ; Han, Man-Soo ; Lee, Heyung-Sub ; Kim, Bong-Tae ; Kim, Whan-Woo ;
ETRI Journal, volume 26, issue 5, 2004, Pages 505~505
We propose a new arbitration method for an input buffered switch with a buffered crossbar. In the proposed method, an exhaustive polling method is used to decrease the synchronization. Using an approximate analysis, we explain how the proposed method improves the switch performance. Also, using computer simulations, we show the proposed method outperforms the previous methods under burst traffic.
Novel Current Driving Circuit for Active Matrix Organic Light Emitting Diode
Yang, Yil-Suk ; Roh, Tae-Moon ; Lee, Dae-Woo ; Kwon, Woo-H. ; Kim, Jong-Dae ;
ETRI Journal, volume 26, issue 5, 2004, Pages 509~509
This paper describes a novel current driving circuit for an active matrix organic light emitting diode (AMOLED). The proposed current driving circuit has a lower power consumption and higher chip density for the AMOLED display compared with the conventional one because all elements operate at a normal voltage and are shielded from the high voltage of the panel. The chip size and power consumption of the current driving circuit for an AMOLED can be improved by about 30 to 40% and 10 to 20%, respectively, compared with the conventional one.