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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 25, Issue 12B - Dec 2000
Volume 25, Issue 12A - Dec 2000
Volume 25, Issue 11B - Nov 2000
Volume 25, Issue 11A - Nov 2000
Volume 25, Issue 10B - Oct 2000
Volume 25, Issue 10A - Oct 2000
Volume 25, Issue 9B - Sep 2000
Volume 25, Issue 9A - Sep 2000
Volume 25, Issue 8B - Aug 2000
Volume 25, Issue 8A - Aug 2000
Volume 25, Issue 7B - Jul 2000
Volume 25, Issue 7A - Jul 2000
Volume 25, Issue 6B - Jun 2000
Volume 25, Issue 6A - Jun 2000
Volume 25, Issue 5B - May 2000
Volume 25, Issue 5A - May 2000
Volume 25, Issue 4B - Apr 2000
Volume 25, Issue 4A - Apr 2000
Volume 25, Issue 3B - Mar 2000
Volume 25, Issue 3A - Mar 2000
Volume 25, Issue 1B - Jan 2000
Volume 25, Issue 1A - Jan 2000
Volume 25, Issue 9 - 00 2000
Volume 25, Issue 8 - 00 2000
Volume 25, Issue 7 - 00 2000
Volume 25, Issue 5 - 00 2000
Volume 25, Issue 4 - 00 2000
Volume 25, Issue 2B - 00 2000
Volume 25, Issue 2A - 00 2000
Volume 25, Issue 1 - 00 2000
Volume 25, Issue 12 - 00 2000
Volume 25, Issue 10 - 00 2000
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Bit Error Bounds for Trellis Coded Asymmetric 8PSK in Rain Fading Channel
The Journal of Korean Institute of Communications and Information Sciences, volume 25, issue 5B, 2000, Pages 797~808
This paper presents the bit error rate(BER) upper bounds for trellis coded asymmetric 8PSK(TC-A8PSK) system using the Ka-band satellite in the rain fading environment. The probability density function(PDF) for the rain fading random variable can be theoretically derived by assuming that the rain attenuation can be approximated to a long-normal distribution and the rain fading parameters are calculated by using the rain precipitation data from the Crane global model. Furthermore, we analyze the BER upper bounds of TC-A8PSK system according to the number of states in the trellis diagram and the availability of channel state information(CSI). In the past, Divsalar and Simon has analyzed the BER upper bounds of 2-state TCM system in Rician fading channels however this paper is the first to analyze the BER upper bounds of TCM system in the rain fading channels. Finally, we summarize the dominant six factors which are closely related to the BER upper bounds of TC-A8PSK satellite system in the rain fading channel as follows: 1) frequency band, 2) rain intensity, 3) elevation angle, 4) signal to noise ratio, 5) asymmetric angle, and 6) availability of CSI.
An Optimal Capacity Allocation Problem in Designing advanced Information Communication Processing System
The Journal of Korean Institute of Communications and Information Sciences, volume 25, issue 5B, 2000, Pages 809~819
This paper deals with an optimal capacity allocation problem and performance analysis in Advanced Information Communication Processing System(AICPS). AICPS is a gateway system interconnection PSTN(Public Switched Telephone Network), ISDN(Intergrated Services Digital Network), PSDN(Packet Switched Data Network), internet, Frame Relay and ATM together. This study considers not only ISDN and Internet but also user behavior of On-line service which is analyzed by Markov process. A call blocking probability of TNAS and INAS is computed by Erlang's formula. Then, PNAS and WNAS's call blocking probability are computed by Stochastic knapsack modeling. The result is compared with result of simulation. Finally, we allocate an optimal capacity minimizing total call blocking probability.
Performance Evaluation of Dynamic signalling Period Allocation Algorithm for Wireless ATM MAC Protocols under Mixed Traffic Conditions
The Journal of Korean Institute of Communications and Information Sciences, volume 25, issue 5B, 2000, Pages 820~829
In this paper, DSPA(Dynamic Signalling Period Allocation) algorithm that has been proposed by the authors for MAC(Medium Access Control) protocols in W-ATM(Wireless Asynchronous Transfer Mode) is applied to mixed traffic conditions composed of various service classes. We investigate the bandwidth utilization efficiency and quality of service(QoS) fulfillment by the DSPA algorithm used in W-ATM MAC protocols. Simulation results indicate that the DSPA algorithm significantly increases the throughput of the system with the minimum control overhead. Moreover, QoS of each service class is well satisfied by proper and fair channel allocation to different service classes according to their requirements.
A study on the Improved Convergence Characteristic over Weight Updating of Recycling Buffer RLS Algorithm
The Journal of Korean Institute of Communications and Information Sciences, volume 25, issue 5B, 2000, Pages 830~841
We extend the sue of the method of least square to develop a recursive algorithm for the design of adaptive transversal filters such that, given the least-square estimate of this vector of the filter at iteration n-1, we may compute the updated estimate of this vector at iteration a upon the arrival of new data. We begin the development of the RLS algorithm by reviewing some basic relations that pertain to the method of least squares. Then, by exploiting a relation in matrix algebra known as the matrix inversion lemma, we develop the RLS algorithm. An important feature of the RLS algorithm is that it utilizes information contained in the input data, extending back to the instant of time when the algorithm is initiated. In this paper, we propose new tap weight updated RLS algorithm in adaptive transversal filter with data-recycling buffer structure. We prove that convergence speed of learning curve of RLS algorithm with data-recycling buffer is faster than it of exiting RL algorithm to mean square error versus iteration number. Also the resulting rate of convergence is typically an order of magnitude faster than the simple LMS algorithm. We show that the number of desired sample is portion to increase to converge the specified value from the three dimension simulation result of mean square error according to the degree of channel amplitude distortion and data-recycle buffer number. This improvement of convergence character in performance, is achieved at the (B+1)times of convergence speed of mean square error increase in data recycle buffer number with new proposed RLS algorithm.
Performance Analysis of the Multicasting Protocol Using Division of the Control Channel in WDM Networks
The Journal of Korean Institute of Communications and Information Sciences, volume 25, issue 5B, 2000, Pages 842~849
In this paper, We analyzed the protocol to improve the performance of the multicast traffic processing in WDM networks. In the protocol, control channels are devided into contention-less minislots and contention minislots. And the packets which fail to have successful reservation in the present time slot have priority to have successful reservation in the contention-less minislots of the next time slot. Therefore, control channel contentions and destination conflicts can be reduced with the use of contention-less minislots. For the multicast traffic processing, the theoretical analysis and computer simulation are important to estimate the network performance and to calculate the optimized number of contention-less minislots. In this paper, the state transition probability of the number of contention-less minislots and arrival packets are calculated using 4-dimension matrix. The maximum number of contention-less minislots is equal to the number of channels for maximum performance improvement of the system. It is theoretical analysis and prove to computer simulation the performance of the protocol.
A Restoration Stategy using Backup VPs on ATM/B-ISDN according to Service Categories
The Journal of Korean Institute of Communications and Information Sciences, volume 25, issue 5B, 2000, Pages 850~858
Increased network reliability is required as the size of communication network becomes larger and the bandwidth requirement is increasing. And preparing of backup path is required to protect the network from serious network failures in high speed network. In this paper, we construct multiple logical networks on a physical ATM network according to the ATM bearer service category(CBR, rt-VBR, nrt-VBR, ABR, UBR) defined by ATM Forum to support the required QoS(Quality of Service) and to manage the network more efficiently. We use backup path restoration algorithm rather than dynamic restoration to achieve rapid restoration when active path fails and we use fault management function in TINA. We propose a restoration scheme that is suitable for high-speed network.
An ASIC Chip Design of an DFDM-based 25 Mbps Wireless ATM Moderm Using Cyclic Suffix
The Journal of Korean Institute of Communications and Information Sciences, volume 25, issue 5B, 2000, Pages 859~870
In this paper, an efficient H/W implementation technique for guard interval in OFDM(Orthogonal Frequency Division Multiplexing) systems is proposed and applied to ASIC chip design of an OFDM-based 25 Mbps wireless ATM modem. In OFDM systems, a cyclic prefix, longer than the largest multipath delay spread, is usually inserted to maintain the orthogonality of subchannels, by making the linear convolution of the channel ok like circular convolution inherent to the discreate Fourier domain, as well as to prevent the ISI(Intersymbol Interference) within the OFDM block. However, the OFDM system using the cyclic prefix requires an additional H/W in transmitter in order to store the original samples and to append the cyclic prefix to the beginning of each block. In this paper, a new approach using a cyclic prefix, even with a significantly lower H/W complexity. Finally, the performance of the proposed approach is demonstrated by applying it to ASIC chip design of an OFDM-based 25 Mbps wireless ATM modem.
Packet Acquisition for DS/CDMA-based LEO Satellite communication System
The Journal of Korean Institute of Communications and Information Sciences, volume 25, issue 5B, 2000, Pages 871~878
A divided matched filter-reference filter(MF-RF) technique for LEO satellite packet transmission is proposed to increase the packet throughput in the presence of severe Doppler shift and fading. To overcome the severe Doppler shift, the divided matched filter is adopted where the integration region of matched filter is divided and ouputs of divided matched filer are added to decide the correct pseudo-noise (PN) phase. To maintain the constant false alarm rate in time varying interference and fading channel, the adaptive threshold for acquisition is obtained from the reference filter. As a performance measure, average acquisition time and packet throughput are used, and the effets of the parameters, i.e., Doppler shift, chip energy to noise ratio, user velocity, standard deviation of shadowing, and preamble length are shown.
Performance Analysis of Multi-Code CDMA System over IS-95B Forward Channel
The Journal of Korean Institute of Communications and Information Sciences, volume 25, issue 5B, 2000, Pages 879~888
In this paper, the performance of IS-95B CDMA system adopting multi-code scheme for data service on the forward link is obtained by theoretical analysis and computer simulation. The wireless channel is assumed to include AWGN, MUI(Multi-User Interference), and MPI(Multi-Path Interference), and multipath Rayleigh fading modeled by TDL(Tapped Delay Line). To obtain actual performance, IS-95B system using PN codes(M-sequence) concatenated with Walsh codes is considered. The BER performance of voice/data service satisfying QoS requirement and the maximum capacity of voice users is derived in terms of various system parameters(voice activity factor, required SNR of voice/data users, the number of multi-codes, the number of voice/data users.,etc.). As a result, under the condition that the maximum allowable number of voice user is 38 in voice only system, as the number of multi-code is decreased by 1, the maximum allowable number of voice user is increased by 5% for system with 1 data user and 22.3% for system with 4 data users. Therefore, it is possible to increase maximum allowable number of users in IS-95B CDMA system by appropriate control of the number of multi-codes and required SNR according to channel environment and traffic characteristic.
Configuration Design of a WDM Mesh Backbone Network
The Journal of Korean Institute of Communications and Information Sciences, volume 25, issue 5B, 2000, Pages 889~898
In order to support various broadband multimedia servies in the future, we designed a well balanced WDM backbone network. In Korean network traffic environment, six regional centers are selected, link capacities between the regional centers are estimated from the PDI traffic model, and the overall network configuration is designed for the all-optical backbone network. Also, we designed a basic configuration to be able to protect minimum communication capability against link failure. A simulation study is carried out to verify the desired performance of the designed WDM backbone network. Simulation results show that performance of the backbone network is well balanced to support various communication services in Korea in the mid 2000s
Performance Improvement for PVM by Zero-copy Mechanism
The Journal of Korean Institute of Communications and Information Sciences, volume 25, issue 5B, 2000, Pages 899~912
PVM provides users with a single image of high performance parallel computing machine by collecting machines distributed over a network. Low communication overhead is essential to effectively run applications on PVM based platforms. In the original PVM, three times of memory copies are required for a PVM task to send a message to a remote task, which results in performance degradation. We propose a zero-copy model using global shared memory that can be accessed by PVM tasks, PVM daemon, and network interface card(NIC). In the scheme, a task packs data into global shared memory, and notify daemon that the data is ready to be sent, then daemon routes the data to a remote task to which it is sent with no virtual data copy overhead. Experimental result reveals that the message round trip time between two machines is reduced significantly in the proposed zero-copy scheme.
Video Retrieval based on Objects Motion Trajectory
The Journal of Korean Institute of Communications and Information Sciences, volume 25, issue 5B, 2000, Pages 913~924
This paper proposes an efficient descriptor for objects motion trajectory and a video retrieval algorithm based on objects motion trajectory. The algorithm describes parameters with coefficients of 2-order polynomial for objects motion trajectory after segmentation of the object from the scene. The algorithm also identifies types, intervals, and magnitude of global motion caused by camera motion and indexes them with 6-affine parameters. This paper implements content-based video retrieval using similarity-match between indexed parameters and queried ones for objects motion trajectory. The proposed algorithm will support not only faster retrieval for general videos but efficient operation for unmanned video surveillance system.
A Scheme of the Distributed Path Assignment in Network with Hierarchical Topology
The Journal of Korean Institute of Communications and Information Sciences, volume 25, issue 5B, 2000, Pages 925~930
The Problem of allocating paths is very significant in order to transmit a large amount of various data on the ATM network. Therefore, selecting an optimal path among available paths between the a source node and a target node has been researched. Alternate paths designed in previous PNNI routing is not considered on the group-occupation so that traffic congestion happens, when errors occur in the network which consists of a hierarchical network architecture extendable to a large network, We propose the Top-Down algorithm considering an average of the occupation among the groups reported from a leader node in each group and minimizing a traffic congestion
A Serial Acquisition Scheme for DS-SS Systems Using Antenna Arrays and Its Performance in a Fading Channel
The Journal of Korean Institute of Communications and Information Sciences, volume 25, issue 5B, 2000, Pages 931~941
We propose a serial acquisition scheme using antenna arrays for initial acquisition of direct sequence spread spectrum (DS-SS) signals, which can lower substantially the range of detectable signal-to-noise ratio (SNR). The proposed scheme uses the sum of the independent decision samples form psedo-noise (PN) co-phased noncoherent I-Q matched filters (MFs) associated with antenna arrays as a decision variable in order to enhance SNR of the resulting signal. We analyze its mean acquisition time performance under an additive white Gaussian noise (AWGN) channel and a flat Rayleigh fading channel by deriving the expressions for the probabilities of detection and false alarm. From mumerical results, we see that the acquisition performance of the proposal scheme becomes improved continually as the number of antennas increse
A Dynamic Queue Manager for Optimizing the Resource and Performance of Mass-call based IN Services in Joint Wired and Wireless Networks
The Journal of Korean Institute of Communications and Information Sciences, volume 25, issue 5B, 2000, Pages 942~955
This paper proposes enhanced designs of global service logic and information flow for the mass-call based IN service, which increase call completion rates and optimize the resource in joint wired and wireless networks. In order to hanve this logic implemented, we design a Dynamic Queue Manager(DQM) applied to the call queuing service feature in the Service Control Point(SCP). In order to apply this logic to wireless service subscribers as well as wired service subscribers, the service registration flags between the Home Location Register(HLR) and the SCP are managed to notify the DQM of the corresponding service subscribers’ mobility. Hence, we present a dynamic queue management mechanism, which dynamically manages the service group and the queue size based on M/M/c/K queueing model as the wireless subscribers roam the service groups due to their mobility characteristics. In order to determine the queue size allocated by the DQM, we simulator and analyze the relationship between the number of the subscriber’s terminals and the drop rate by considering the service increment rate. The appropriate waiting time in the queue as required is simulated according to the above relationship. Moreover, we design and implement the DQM that includes internal service logic interacting with SIBs(Service Independent building Blocks) and its data structure.
Traffic Grooming Algorithm for Minimizing the Number of SONET ADMs in WDM Ring Networks
The Journal of Korean Institute of Communications and Information Sciences, volume 25, issue 5B, 2000, Pages 956~965
In this paper, we propose an efficient traffic grooming algorithm to minimize to number of SONET ADMs which is the dominant cost of system in high speed optical ring networks. It is an optimal traffic grooming algorithm to be applied to both unidirectional ring and bi-directional ring under both uniform traffic and nonuniform traffic. The proposed traffic grooming algorithm consists of two subalgorithms : one is the algorithm to construct full connection-rings as many as possible to minimize gaps by cutting the connections and using redirection method, and the other is the algorithm to groom connection-rings into a wavelength to maximize the number of shared nodes. The simulation results show that the proposed algorithm is superior to conventional algorithm under various network conditions.
Design of a (204, 188) Reed-Solomon Decoder
The Journal of Korean Institute of Communications and Information Sciences, volume 25, issue 5B, 2000, Pages 966~973
In this paper, we propose a novel RS decoder design yielding smallr circuit size shorter coding latency. The proposed architecture of RS decoder has the following two features. First, circuit size reduced by using Euclid algorithm with mutual operation between cells. Second, coding latency is reduced by using higher frequency than syndrome and error value calculation block. We performed simulation with C language and MATLAB in order to verify the decoding algorithm and implemented using FPGA chips in VHDL.
A CMOS Voltage Driver for Voltage Down Converter
The Journal of Korean Institute of Communications and Information Sciences, volume 25, issue 5B, 2000, Pages 974~984
A CMOS voltage driver circuit for voltage down converter is proposed. An adaptive biasing technique is used to enhance load regulation characteristics. The proposed driver circuit uses the NMOS transistor as a driving transistor, so it does not suffer from large Miller capacitances which is one of the problems with conventional PMOS driving transistor, and hence achieves good phase margin and stable frequency response. No additional complex circuit for frequency compensation such as compensation capacitor is required in this implementation. For the same current capability, the size of NMOS transistor in driver circuit is smaller than that of PMOS counterpart. So the smaller die area can be achieved. The circuits is implemented using a 0.8
CMOS process and has a die area of 150
. Proposed circuit has a quiescent power of 60 . In the current driving range from 100
to 50 ㎃, load regulation of 5.6 ㎷ is measured.
A Study on the Design and Fabrication of GHz Magnetic Thin Film Inductor Utilizing Co90Fe10/SiO2 Multilayer
The Journal of Korean Institute of Communications and Information Sciences, volume 25, issue 5B, 2000, Pages 985~991
In this paper, the optimum structure of 2GHz magnetic thin film planar inductor were designed and fabricated to reduce the inductor area and to maximize the inductance L and quality factor Q of the inductor. The optimum design was performed utilizing Co90Fe10 layer multilayered with SiO2 layers to avoid the eddy-current skin effect and considering new lumped element model. New magnetic thin film inductors operating at 2GHz were fabricated on a Si substrate utilizing photo-lithography and lift-off techniques. The frequency characteristics of L, Q, and impedance in more than fifty identical inductors were measured using an RF Impedance Analyzer(HP4291B with HP16193A test fixture). The self-resonant frequencies(SRF) of the inductors were measured by a Vector Network Analyzer(HP8510). The developed inductors have SRF of 1.8 to 2.3GHz, L of 47 to 68nH, and Q of 70 to 80 near 1GHz. Finally, high frequency, high performance, planar micro-inductor(area=30.8 x 30.8il
) with maximized L and Q were fabricated succefully.