Browsing by Author "LEE, TH"

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ANALYTIC MODELS FOR PERFORMANCE EVALUATION OF SINGLE-BUFFERED BANYAN NETWORKS UNDER NONUNIFORM TRAFFIC
(1991-01-01)
LEE, TH
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交大名義發表
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電信工程研究所
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National Chiao Tung University
;
Institute of Communications Engineering
The performance of single-buffered banyan networks under certain nonuniform traffic patterns had been studied by Garg and Huang. However, the models used are over simplified and the results obtained may deviate from exact values significantly. Alternative models to achieve more accurate performance estimates are presented. In our models, the destinations of blocked packets residing in the buffers of nodes at stage 1 (and perhaps stage 2, depending on the traffic matrix) are memorised. Compared with those adopted by Garg and Huang, our models are only slightly more complicated. By viewing banyan networks as queueing systems, we apply Little's formula to compute the average packet delays.
APPROXIMATE EXPRESSION FOR NORMALIZED THROUGHPUT OF MULTISTAGE INTERCONNECTION NETWORKS
(1990-11-22)
LEE, TH
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CHOU, JJ
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交大名義發表
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電信工程研究所
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National Chiao Tung University
BANYAN NETWORK NONBLOCKING WITH RESPECT TO CYCLIC SHIFTS
(1991-08-01)
LEE, TH
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LIU, SJ
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電信工程研究所
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電信研究中心
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Institute of Communications Engineering
The nonblocking property of banyan network with respect to cyclic shifts is proved. The property is used to design a fair nonblocking copy network for multicast packet switching. The performance of the designed copy network is evaluated.
BEHAVIOR OF CIRCUIT-SWITCHED MULTISTAGE NETWORKS IN PRESENCE OF MEMORY HOT SPOT - COMMENT
(1990-04-12)
LEE, TH
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交大名義發表
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電信工程研究所
;
National Chiao Tung University
;
Institute of Communications Engineering
CALL ADMISSION CONTROL FOR ATM NETWORKS USING INSTANTANEOUS QOS ESTIMATES
(1993)
LEE, TH
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LAI, KC
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DUANN, ST
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傳播研究所
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Institute of Communication Studies
DESIGN AND ANALYSIS OF A NEW SELF-ROUTING NETWORK
(1992-01-01)
LEE, TH
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電信工程研究所
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電信研究中心
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Institute of Communications Engineering
;
Center for Telecommunications Research
A new self-routing network constructed from the sorting and the routing cells is proposed. The complexity of the new network is roughly twice as much as that of a pure banyan network. The new network can be viewed as an implementation of the load-sharing network [6] which requires a very simple management. Its performance under uniform and nonuniform traffic models is analyzed for the unbuffered case. It is found that a higher degree of nonuniformity results in a better performance for certain form of nonuniform traffic matrices. Simulations are performed to obtain the normalized throughputs and mean packet delays for the single-buffered case. Different from single-buffered pure banyan networks [10], the mean delay of high-traffic packets is smaller than that of low-traffic packets for a particular form of nonuniform traffic matrices. In addition to performance improvement, the new network is easy to diagnose. Some variations of the proposed network are also studied.
DETECTION AND LOCATION FOR SINGLE FAULTS IN BITONIC SORTERS
(1994)
LEE, TH
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CHOU, JJ
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電信工程研究所
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Institute of Communications Engineering
DIAGNOSIS OF SINGLE FAULTS IN BITONIC SORTERS
(1994-10-01)
LEE, TH
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CHOU, JJ
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電控工程研究所
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電信工程研究所
;
Institute of Electrical and Control Engineering
Bitonic sorters have recently been proposed to construct along with banyan networks the switching fabric of future broadband networks [2]. Unfortunately, a single fault in a bitonic sorter may have disastrous consequences for the switching system. Therefore, a bitonic sorter must be proved to be free of faults before it can be used. In this paper we study the topological properties of bitonic sorters and present an efficient fault diagnosis procedure to detect, locate, and identify the fault type of single faults. Our diagnosis procedure can detect most single faults in two tests. Faults which cannot be detected in two tests can always be detected in four tests. Several binary search techniques are developed to locate a faulty sorting element (i.e,, a 2 x 2 sorter).
DOWNLINK POWER-CONTROL ALGORITHMS FOR CELLULAR RADIO SYSTEMS
(1995-02-01)
LEE, TH
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LIN, JC
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SU, YT
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電控工程研究所
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電信工程研究所
Power control is an effective technique to reduce cochannel interference and increase capacity for cellular radio systems, Optimum centralized power control can minimize the outage probability, but requires the information of all link gains in real time, which is very difficult to successfully implement for a large system; besides, the computational complexity of an optimum power control algorithm makes it impractical for real implementations. In this paper, we propose some centralized power control algorithms with reasonable computational complexity, One of the algorithms, called the SMIRA algorithm, has an outage probability that is very close to the minimum, We also study a class of distributed power control algorithms that can achieve a balanced carrier-to-interference ratio with probability one, Among the class of algorithms, we found that the one proposed in [6] gives the minimum outage probability.
Identification of fault types for single faults in bitonic sorters
(1995)
LEE, TH
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CHOU, JJ
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電信工程研究所
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Institute of Communications Engineering
IMPROVING PERFORMANCE OF MULTIDESTINATION ARQ SCHEMES UNDER HIGH ERROR RATE CONDITIONS
(1991-01-31)
LEE, TH
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交大名義發表
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電信工程研究所
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National Chiao Tung University
;
Institute of Communications Engineering
The throughput efficiencies of a class of continuous multi-destination ARQ schemes are evaluated. The operation of the proposed schemes is simpler than that of the schemes studied previously. Numerical results also show that the optimal proposed scheme offers a better throughput performance than the optimal one investigated previously.
MULTICASTING IN A SHARED BUFFER MEMORY SWITCH
(1993)
LEE, TH
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LIU, SJ
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電信工程研究所
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Institute of Communications Engineering
PERFORMANCE ANALYSIS OF A LARGE SCALE ATM SWITCH WITH INPUT AND OUTPUT BUFFERS
(1994)
LEE, TH
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LIU, SJ
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電控工程研究所
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Institute of Electrical and Control Engineering
PERFORMANCE ANALYSIS OF EFFICIENT CONCATENATED CODING SCHEME FOR ARQ PROTOCOLS
(1991-06-01)
LEE, TH
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電信工程研究所
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電信研究中心
;
Institute of Communications Engineering
;
Center for Telecommunications Research
Benelli investigated the performance of two concatenated coding schemes for ARQ protocols. The two schemes differ in their strategies of retransmission. It was shown that the two schemes proposed by Benelli provide a significant improvement in throughput efficiency of ARQ protocols with respect to other similar schemes. The analysis presented by Benelli is complicated. An alternative analysis is provided. Some implementation problems of the Benelli's schemes are also discussed. An efficient retransmission strategy which avoids unnecessary retransmissions and maintains a fixed decoding complexity is proposed.
PERFORMANCE OF BANYAN NETWORKS WITH INHOMOGENEOUS TRAFFIC FLOW
(1990-07-01)
LEE, TH
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交大名義發表
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電信工程研究所
;
National Chiao Tung University
;
Institute of Communications Engineering
PERFORMANCE OF MULTISTAGE INTERCONNECTION NETWORKS FOR INTEGRATED SERVICES
(1990-03-29)
LEE, TH
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交大名義發表
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電信工程研究所
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National Chiao Tung University
;
Institute of Communications Engineering
PERFORMANCE OF SOME MULTIDESTINATION GBN ARQ PROTOCOLS UNDER UNEQUAL ROUND-TRIP DELAYS
(1993-11-01)
LEE, TH
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HU, JK
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交大名義發表
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電信工程研究所
;
National Chiao Tung University
The performance of various ARQ protocols has recently been analyzed for multidestination environments. In all previous work, the round-trip delays between the transmitter and each of the receivers are assumed (or forced) to be equal to the maximum one, to simplify the analysis and/or the operation. This assumption obviously will sacrifice the system performance. In this paper, we evaluate the throughput efficiencies of three multidestination GBN ARQ protocols under unequal round-trip delays. In the investigated protocols, multiple copies of each data block are (re)transmitted contiguously to the receivers. Tight lower bounds are obtained for the throughput efficiencies of the schemes in which each data block is transmitted with the optimum number of copies. Results show that assuming all the round-trip delays to be equal to the maximum one may sacrifice the performance significantly. We also compare the performances of the three investigated protocols. In general, the performance becomes better as the transmitter utilizes more of the outcomes of previous transmission attempts.
POWER-CONTROL ALGORITHM FOR CELLULAR RADIO SYSTEMS
(1994-02-03)
LIN, JC
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LEE, TH
;
SU, YT
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電控工程研究所
;
電信工程研究所
In a recent paper, Zander presented an optimum transmitter power control scheme to minimise the outage probability for cellular systems and proposed the stepwise removal algorithm (SRA) for use in practical implementations. In the Letter, the authors present a new power control algorithm which considers the transmitter power together with fink gams. The algorithm provides better outage probability with only a negligible increase in computational complexity.
REAL-TIME CALL ADMISSION CONTROL FOR ATM NETWORKS WITH HETEROGENEOUS BURSTY TRAFFIC
(1994)
LEE, TH
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LAI, KC
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DUANN, ST
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傳播研究所
;
Institute of Communication Studies
SIMPLE IMPLEMENTATION OF LOAD-SHARING BANYAN NETWORK AND ITS THROUGHPUT PERFORMANCE
(1990-01-04)
LEE, TH
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交大名義發表
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電信工程研究所
;
National Chiao Tung University
;
Institute of Communications Engineering