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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Journal of Korean Institute of Communications and Information Sciences
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The Korean Institute of Communications and Information Sciences
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Volume & Issues
Volume 30, Issue 12C - Dec 2005
Volume 30, Issue 12B - Dec 2005
Volume 30, Issue 12A - Dec 2005
Volume 30, Issue 11C - Nov 2005
Volume 30, Issue 11B - Nov 2005
Volume 30, Issue 11A - Nov 2005
Volume 30, Issue 10C - Oct 2005
Volume 30, Issue 10B - Oct 2005
Volume 30, Issue 10A - Oct 2005
Volume 30, Issue 9C - Sep 2005
Volume 30, Issue 9B - Sep 2005
Volume 30, Issue 9A - Sep 2005
Volume 30, Issue 8C - Aug 2005
Volume 30, Issue 8B - Aug 2005
Volume 30, Issue 8A - Aug 2005
Volume 30, Issue 7C - Jul 2005
Volume 30, Issue 7B - Jul 2005
Volume 30, Issue 7A - Jul 2005
Volume 30, Issue 6C - Jun 2005
Volume 30, Issue 6B - Jun 2005
Volume 30, Issue 6A - Jun 2005
Volume 30, Issue 5C - May 2005
Volume 30, Issue 5B - May 2005
Volume 30, Issue 5A - May 2005
Volume 30, Issue 4C - Apr 2005
Volume 30, Issue 4B - Apr 2005
Volume 30, Issue 4A - Apr 2005
Volume 30, Issue 3C - Mar 2005
Volume 30, Issue 3B - Mar 2005
Volume 30, Issue 3A - Mar 2005
Volume 30, Issue 2C - Feb 2005
Volume 30, Issue 2B - Feb 2005
Volume 30, Issue 2A - Feb 2005
Volume 30, Issue 1C - Jan 2005
Volume 30, Issue 1B - Jan 2005
Volume 30, Issue 1A - Jan 2005
Selecting the target year
Decision Criterion for Weak M-ary Signals: Part 1. The Criterion and Decison Regions
Park, So-Ryoung ; Koo, Jin-Kyu ; Oh, Jong-Ho ; Kwon, Hyoung-Moom ; Song, Iick-Ho ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 9A, 2005, Pages 705~713
A novel decision criterion for weak M-ary signals is proposed in this paper. In the sense of minimizing the error probability, the proposed decision criterion is optimum when the signal strength approaches zero. In Part 1, the proposed detection criterion is proposed and investigated in detail, some interesting properties of the proposed decision criterion are described, and examples of decision regions are obtained. Based on the proposed detection criterion, a detection scheme for ultra wideband multiple access systems is investigated in the presence of impulsive interference in Part 2.
An Efficient Synchronization and Cell Searching Method for OFDMA/TDD System
Kim, Jung-Ju ; Noh, Jung-Ho ; Chang, Kyung-Hi ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 9A, 2005, Pages 714~721
In this parer, we analyze the preamble model in the OFDMA/TDD(OFDM-FDMA/Time Division Duplexing). Besides, under AWGN, ITU-R M.1225 Ped-B and Veh-A channel environments, we analyze capabilities of symbol timing & carrier frequency offset and performance of cell searching capabilities applied to OFDM/TDD system through computer simulation. The performance using Detection Probability, False Alarm Probability, Missing Probability, Mean Acquisition Time and MSE(Mean Square Error) is analyzed. Especially, in the case of symbol timing offset estimation, the preamble structure and its algorithm with enhanced performance are proposed and then compared with existing ones.
Reverse-Link Performance of Synchronous Cellular DS-CDMA Networks in Dispersive Rician Multipath Fading Channels
Hwang Seung-Hoon ; Hanzo Lajos ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 9A, 2005, Pages 722~728
In this paper, the reverse-link performance of synchronous DS-CDMA cellular networks is investigated in Rician multipath fading environments. The system's performance is evaluated in terms of the achievable average bit error rate BER) and the user capacities of two different network layouts, namely those of a uniform grid of hexagonal multiple cells and a single isolated cell. In the multiple-cell scenario, the impact of the other cells' interference on the attainable capacity of the synchronous DS-CDMA uplink is investigated. Upon comparing both networks to a conventional asynchronous CDMA system, we demonstrate an achievable user capacity gain of
for synchronous uplink transmissions over that of the corresponding asynchronous transmission scenario at BER =
Uplink Sub-channel Allocation and Power Control Algorithm Using Ranging Information in High speed Portable Internet System
Kim, Dae-Ho ; Kim, Whan-Woo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 9A, 2005, Pages 729~736
In this paper, we introduce a new approach for the design of uplink sub-channel allocation and power control in the High-speed Portable Internet system that is based on OmMAnDD scheme. In OFDMA system, because the number of allocated sub-channel in mobile station varies from one to the whole sub-channel as in base station while mobile station's transmit power is lower than that of base station, full loading range(FLR) constraint occurs where whole sub-channel can be used and the conventional open-loop power control scheme can not be used beyond FLR. We propose a new scheme that limits the maximum sub-channel allocation number and uses power concentration gain(PCG) depending on location of mobile station, which is based on ranging in OfDMA system. Simulation results show that the proposed scheme extends the uplink coverage to the entire cell service coverage area, provides solutions for optimum utilization of radio resource and enables open-loop power control beyond FLR without extra hardware complexity.
Admission Control for Voice and Stream-Type Data Services in DS-CDMA Cellular System
Chang Jin-weon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 9A, 2005, Pages 737~748
Two flexible admission control schemes for integrated voice and stream-type data services are proposed in DS-CDMA systems. Most Previous studies on admission control have focused on integration of short, bursty Packet-type data services and conventional voice services. However, stream-type data services with a relatively long service holding time are expected to be a considerable portion of data traffic in future generation cellular systems. Scheme I is a basic scheme that accommodates both voice and data services with full bandwidth. However, voice services are given priority over data services using the duration difference between the holding times for these services. Scheme ll uses a different method to efficiently give priority to voice services over stream-type data services. An additional interference margin for voice services is provided by suppressing interference from stream-type data services according to voice access requests and a varying interference status. Performance of the two schemes is evaluated by developing Markovian models. Numerical results show that the voice capacity is highly sensitive to the service holding time of data services while the performance measures of data services are not highly sensitive. Scheme H is a significant improvement over Scheme I for accommodating voice and stream-type data services
The OFDMA/TDD System based on Transmit and Receive Beamforming Utilizing the Preamble for Receive Beamforming
Heo, Joo ; Chang, Kyung-Hi ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 9A, 2005, Pages 749~754
It is well-known that mobile communication systems are usually limited in their performance and capacity by three major impairments, which are multipath fading, delay spread and co-channel interference (CCI). OFDMA (OFDM-FDMA) system can cope with the multipath fading and delay spread easily due to the beneficial properties of OmM technology. Though OFDMA scheme avoids intra-cell interference using the orthogonality among subcarriers, the scheme contains difficulty of reducing co-channel interference. Therefore, in this paper, adaptive antenna techniques are deployed into OFDMA/TDD system to minimize the co-channel interference induced by adjacent cells and to enhance the uplink performance. For the improvement of downlink performance, we apply TxAA (Transmit Adaptive Array), a kind of transmit diversity technique, utilizing preamble symbols for training antenna may into OFDMA/TDD transmitter side. Simulation results show that the uplink and downlink performance under multipath Rayleigh fading channel improved 9dB and 7dB each compared with the case of single antenna system at target BER
An effective channel estimation method considering channel response length in OFDM systems
Jeon Hyoung-Goo ; Choi Won-Chul ; Lee Hyun ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 9A, 2005, Pages 755~761
In this paper, we proposed a channel estimation method by impulse signal train in OFDM. In order to estimate the channel response, 4 impulse signals are generated and transmitted during one OFDM (Orthogonal Frequency Division Multiplexing) symbol. The intervals between the impulse signals are all equal in time domain. At the receiver, the impulse response signals are summed and averaged. And then, the averaged impulse response signal is zero padded and fast Fourier transformed to obtain the channel estimation. The BER performance of the proposed method is compared with those of conventional estimation method using the long training sequence in fast fading environments. The simulation results show that the proposed method improves by 3 dB in terms of Eb/No, compared with the conventional method.
An Efficient Priority Based Adaptive QoS Traffic Control Scheme for Wireless Access Networks
Kang Moon-sik ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 9A, 2005, Pages 762~771
In this paper, an efficient Adaptive quality-of-service (QoS) traffic control scheme with priority scheduling is proposed for the multimedia traffic transmission over wireless access networks. The objective of the proposed adaptive QoS control (AQC) scheme is to realize end-to-end QoS, to be scalable without the excess signaling process, and to adapt dynamically to the network traffic state according to traffic flow characteristics. Here, the reservation scheme can be used over the wireless access network in order to get the per-flow guarantees necessary for implementation of some kinds of multimedia applications. The AQC model is based on both differentiated service model with different lier hop behaviors and priority scheduling one. It consists of several various routers, access points, and bandwidth broker and adopts the IEEE 802.1 le wireless radio technique for wireless access interface. The AQC scheme includes queue management and packet scheduler to transmit class-based packets with different per hop behaviors (PHBs). Simulation results demonstrate effectiveness of the proposed AQC scheme.
Performance of Space Time Block Coded-Spatial Multiplexing Systems in Limited Feedback Channel
Hwang, Hyeon-Chyeol ; Shin, Seung-Hoon ; Lim, Jong-Kyoung ; Kim, Seok-Ho ; Kwak, Kyung-Sup ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 9A, 2005, Pages 772~780
In this paper, an efficient pre-processing in space tine block coded-spatial multiplexing systems is presented. The pre-processing scheme is designed empirically with extending the diagonally weighted orthogonal space time-block coded diversity system to spatial multiplexing system. Simulation results show the proposed scheme outperforms both the precoder using the predefued codebooks and typical antenna selection scheme over moderate doppler frequency in limited feedback channel.
A Method of Intercell Carrier Frequency-offset Estimation and Cell-searching for Downlink in OFDM-Based Cellular Systems
Park Kyung-won ; Cho Yong-soo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 9A, 2005, Pages 781~787
In this paper, an estimation method of intercell carrier frequency-offset(CFO) in orthogonal frequency division multiplexing(OFDM)-based cellular systems is proposed for a user's equipment(UE), especially at the cell boundary, in downlink channels. Also, after deriving an estimation method of intercell CFO from the signals received by adjacent base stations(BSs), we propose a cell-searching method using the estimated CFOs. It is shown by computer simulation that the proposed methods can uniquely estimate the intercell CFOs and identify the target BS with a high detection probability.
Transmit Antenna Selection for Dual Polarized Channel Using Singular Value Decision
Lee Sang-yub ; Mun Cheol ; Yook Jong-gwan ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 9A, 2005, Pages 788~794
In this paper, we focus on the potential of dual polarized antennas in mobile system. thus, this paper designs exact dual polarized channel with Spatial Channel Model (SCM) and investigates the performance for certain environment. Using proposed the channel model; we know estimates of the channel capacity as a function of cross polarization discrimination (XPD) and spatial fading correlation. It is important that the MIMO channel matrix consists of Kronecker product dividable spatial and polarized channel. Through the channel characteristics, we propose an algorithm for the adaptation of transmit antenna configuration to time varying propagation environments. The optimal active transmit antenna subset is determined with equal power allocated to the active transmit antennas, assuming no feedback information on types of the selected antennas. We first consider a heuristic decision strategy in which the optimal active transmit antenna subset and its system capacity are determined such that the transmission data rate is maximized among all possible types. This paper then proposes singular values decision procedure consisting of Kronecker product with spatial and polarize channel. This method of singular value decision, which the first channel environments is determined using singular values of spatial channel part which is made of environment parameters and distance between antennas. level of correlation. Then we will select antenna which have various polarization type. After spatial channel structure is decided, we contact polarization types which have considerable cases It is note that the proposed algorithms and analysis of dual polarized channel using SCM (Spatial Channel Model) optimize channel capacity and reduce the number of transmit antenna selection compare to heuristic method which has considerable 100 cases.
Perfonnance Analysis of Binary CDMA systems in Multi-Path Fading Channel
Ko Jae-Yun ; Lee Yong-Hwan ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 9A, 2005, Pages 795~802
Binary CDMA(B-CDMA) is a new modulation scheme that employs a constant envelope modulation scheme By quantizing the envelope of multi-codes CDMA signal into a small number of levels, the B-CDMA can reduce the peak-to-average power ratio, while preserving the advantages of CDMA signaling such as the soft capacity and robustness to interference. In this paper, we analyze the performance of B-CDMA systems in multi-path channel assuming that the spreading factor is not too small. Finally, the analytic results are verified by computer simulation.
Throughput rate of DCF Protocol based Ricean fading channel in the IEEE 802.1la wireless LAN.
Ha Eun-Sil ; Jung Jin-Wook ; Lee Ha-Chul ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 9A, 2005, Pages 803~813
This paper explores the throughput performance of CSMA/CA-based DCF protocol over frequency-selective, slow Ricean fading channels with both the
and BER at the MAC layer in the 802.1 la wireless LAN. By exploring the throughput of DCF protocol with the data rate of 6Mbps, 12 Mbps, 24 Mbps and 54 Mbps, we find the fact that the higher the
be and the less the BER be, the higher the throughput be.
ALOHA-type Anti-collision Algorithms Using Tag Estimation Method in RFID system
Cha Jae-Ryong ; Kim Jae-Hyun ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 9A, 2005, Pages 814~821
When there are many tags using the same frequency around the reader in RFID system, they disturb each other and in the end their response cannot be received by the reader. To solve this disturbance and fast identify the tags, the anti-collision algorithm, which is the core technology in RFID system, is needed. We propose two ALOHA-type Dynamic Framed Slotted ALOHA(DFS-ALOHA) algorithms using Dynamic Slot Allocation(DSA), which dynamically allocates the frame size in accordance with the number of tags and Tag Estimation Method(TEM), which estimates the number of tags around the reader. We also compare the performance of the proposed DFS-ALOHA algorithms with that of the conventional Framed Slotted ALOHA (FS-ALOHA) algorithms and the algorithms proposed by Vogt using OPNET simulation. According to the analysis, the two proposed DFS-ALOHA algorithms(DFS-ALOHA I and DFS-ALOHA II) show better performance than the conventional ALOHA-based algorithms regardless of the number of tags. Although the two proposed DFS-ALOHA algorithms show the similar performance, BFS-ALOHA ll is better because it is easier to be implemented in the system and the complexity is lower.
Processing Time and Traffic Capacity Analysis for RFID System Using LBT-Random Searching Scheme
Hwang, In-Kwan ; Lim, Yeon-Jun ; Pyo, Cheol-Sig ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 9A, 2005, Pages 822~829
In this paper, a processing time and trafnc capacity analysis algorithm for RFID system using LBT-Random Searching scheme is proposed. Service time, carrier sensing time, additional delay time required for contiguous frequency channel occupancy, and additional delay time required for the contiguous using the same frequency channel are considered and the processing delay and frequency channel capacity are analyzed for the steady state operation of the system. The simulation results showing maximum capacity of the system and explaining the accuracy of the algorithm are provided.
An Adaptive Linear Channel Equalizer Using Asymmetric Transversal Filter
Han, Jong-Young ; Lim, Dong-Guk ; Kim, Jae-Moung ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 9A, 2005, Pages 830~837
ISI is caused by delay spread in the multipath channel environment. There are two kinds of channel equalizer: Linear and Non-Linear type according to the structures. In this paper, we propose an improved adaptive linear equalizer to mitigate ISI. The proposed adaptive equalizer is constructed by using asymmetrical Dsmvenu filter based on USE sub-optimal receiver. Asymmetrical structure of the transversal filter is realized by moving the main tap position from center to side. If this structure is used, we can divide ISI to precusor and postcusor. As a result the proposed equalizer has a larger extended compensation range than conventional adaptive linear equalizer. In computer simulation, we compare the bit error rate performance of the proposed linear equalizer with the conventional one on the S-V channel which is modeled for WB systems.
A Fast Handover Mecllanism in Mobile IPv6 Networks for Reliable Multicasting Services
Shin Seok-Jae ; Yoo Sang-Jo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 9A, 2005, Pages 838~849
Fast handover protocol provides seamless handover in mobile Ipv6 networks by reducing handover latency. This paper proposes FMIP-M mechanism to apply this advantage of fast handover protocol to multicast service. The FMIP-M is a fast handover mechanism that supports a reliable multicast service in mobile Ipv6 networks. When hosts move other networks, they may have seine data missing and out-of-synch problems of multicast data. The proposed mechanism provides reliable multicast transmission by compensating data losses from the previous AR. Also it provides an additional function that is able to change multicasting service types dynamically in accordance with network status related with multicasting. So that it is able to make multicast paths very close to the optimum and more efficient multicast service is possible. The performance of the proposed mechanism is evaluated by a time analysis and simulations in various conditions.
Reliable Transmission Using Intermediate Relay Node-based Transmission for Reliability in Sensor Network
Lee Bo-Hyung ; Yoon Hyung-Wook ; Park Jongho ; Chung Min Young ; Lee Tea-Jin ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 9A, 2005, Pages 850~857
Sensor networks consist of sensor nodes with small size, low cost, lowpower consumption, and multi-functions to sense, to process and to communicate. The main issue in sensor networks has been focused on minimizing power consumption of sensors to maximize network life time. In some critical applications, however, the most important issue is to transmitsensing information to the end user (the sink node) with reliability. Reliable information forwarding using multiple paths in sensor networks (ReinForM) has been proposed to achieve desired reliability in the error-prone channel, but it needs increasing transmission riverhead as the channel error rate becomes high and the number of hops between the source node and the sink node increases. In this paper, we propose a reliable transmission rnechanissmusing intermediate source nodes in sensor networks (ReTrust) to reduce packet overhead while keeping the desired reliability. ReTrust has beenshown to provide desired reliability and reduced overhead via simulationsand analysis.
The Method of high speed Frequency Synchronization Using Spectrum correlation in ATSC terrestrial DTV System
Lee Joo-Hyung ; Song Hyun-Keun ; Nam Wan-Ju ; Kim Jae-Moung ; Kim Seung-Won ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 9A, 2005, Pages 858~866
This paper proposes the method of frequency synchronization using the spectrum correlation in ATSC terrestrial DTV system. If the spectrum around pilot is severely distorted by multipath or mobile reception environment, the conventional algorithm using the pilot signal makes the estimation error of the frequency offset. Because the proposed algorithm acquires frequency synchronization using the correlation between the received specalm and the standard spectrum without the use of pilot, the proposed method can acquire frequency synchronization faster and more accurate than conventional algorithm. And this paper proposes new method for ATSC frequency synchronization without the use of pilot.
Development of Millimeter wave Transmitter and Receiver for Long Distance Wireless Transmission Using NRD waveguide
Park Sung-Hyun ; Kim Soo-Hwan ; hin Cheon-Woo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 30, issue 9A, 2005, Pages 867~875
In this paper, we fabricated along distance wireless communication transmitter and receiver over the 100 which used NRD technology. To make the transmitter and receiver of 400Hz band using the non radiative dielectric wave guide, transmitter was composed of gm oscillator, m modulator and antenna, receiver was composed of local gum oscillator, balanced mixer, 3dB direction coupler and antenna. Also we executed a wireless communication image transmission examination to the transmitter and receiver. We receive the image information in real-time data transmission from receiver after we send the image signal in the wireless distance of the 10km. Therefore, the 400Hz band U transmitter and receiver to be developed will be used widely for the transmission system CATV or broadband transmission system. This will be utilized also to the link device of a long distance high speed wireless communication network.