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Communication Technology Proceedings, 1996. ICCT'96., 1996 International Conference on

Date 5-7 May 1996

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  • Author index

    Publication Year: 1996
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    Freely Available from IEEE
  • Performance evaluation of TCP/RLP protocol stack over CDMA wireless link

    Publication Year: 1996 , Page(s): 710 - 713 vol.2
    Cited by:  Papers (32)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (348 KB)  

    In this paper, we study the system performance of a typical code division multiple access (CDMA) wireless link using a protocol stack in the newly approved data services option standard for wideband spread spectrum digital cellular systems. In particular, we focus on the TCP (transport control protocol) and RLP (radio link protocol) of the protocol stack since the fluctuation of system performance is largely caused by automatic repeat request (ARQ) mechanisms implemented at these two layers. Analytical and simulation results presented here may provide guidance to those attempting to further improve performance of interest View full abstract»

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  • Analysis of a slotted access channel with average cycle method

    Publication Year: 1996 , Page(s): 1080 - 1083 vol.2
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    Random access techniques in the packet broadcasting environment are a very important research topic. A broadcast channel is a radio packet communication channel, and the relative distances between the users and the receiver can vary greatly. Thus, packets from different transmitters arrive at the receiver with substantially different power levels. These phenomena give rise to a capture effect at the receiver. The packet arriving with the highest power level has a good chance of being detected accurately, even when other packets arrive at the same time. This capture effect improves the system throughput and other performance measures. The mean cycle times of the slotted access channel are analyzed by using the average cycle method. Analytic formulae for mean values of a successful period and a colliding period and an idle period are derived. Also, the upper bounds on the throughput of the system with capture effect are provided View full abstract»

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  • Optical fiber personal computer data transmission system for local area networking

    Publication Year: 1996 , Page(s): 1084 - 1087 vol.2
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    This paper describes an improved optical fiber transmission system for personal computer data transmission through analog telephone modems and optical links. The modem is internally connected to the optical link so that the transmission through the optical fibers is complete. The system is constructed using a square-wave frequency modulation (SWFM) scheme for digital data transmission before the electrical output obtained from the modem in fed to the electrical-to-optical converter. The system was used successfully when digital data was transmitted over a distance of 3500 m using multimode graded index (GI) optical fibers View full abstract»

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  • Selection of stuff threshold modulation dither sequences for known SYN-DES operating conditions

    Publication Year: 1996 , Page(s): 825 - 828 vol.2
    Cited by:  Papers (4)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (312 KB)  

    Clock rate adaptation in digital transmission networks such as synchronous optical network (SONET) and synchronous digital hierarchy (SDH), is necessary for two reasons. Firstly, it provides timing transparency for tributaries that are multiplexed at different levels of PDH (pulse stuffing); secondly, it provides timing transparency for transporting the tributaries within the STM frame of the SDH (pointer adjustment). The clock rate adaptation circuits of network synchronizers work by controlling the output data rate by pulse stuffing. The technique of stuff threshold modulation (ST-Mod) is usually used to reduce the waiting time jitter resulting from to pulse stuffing. For a given set of data transmission conditions, the selection of a suitable ST-Mod dither sequence is addressed. It has been shown previously that if the ST-Mod sequence is selected as a sawtooth sequence then it is possible to choose a dither sequence which is optimum for the given operating condition. It is shown that using either a random sequence or a modified wave sequence it is possible to obtain a near optimal filter performance for given synchronizer-desynchronizer (SYN-DES) characteristics View full abstract»

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  • Decision-feedback detection of uncoded/coded MPSK

    Publication Year: 1996 , Page(s): 760 - 763 vol.2
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    A decision-feedback detection technique for MPSK is presented, which uses the previously detected symbols to estimate the initial phase in the current symbol for optimal coherent detection. The theoretical and simulated error performance results for uncoded MPSK are given. It is shown that the error performance of the DF detection is very close to that of ideal coherent detection with differential encoding/encoding which is used to overcome the phase ambiguities. The applications of the DF detection to convolutionally encoded QPSK is given View full abstract»

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  • Pipeline algorithms of RSA data encryption and data compression

    Publication Year: 1996 , Page(s): 1088 - 1091 vol.2
    Cited by:  Papers (1)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (304 KB)  

    Various pipeline algorithms of data compression and encryption are designed to assess the impact of encryption on data compression. The first pipeline shows that encryption fails to map a large amount of redundancy for the input file into a favourable form for its later compression. The second pipeline, however, offers a good potential to improve the compressed output for further compression by another compression algorithm. The pipeline algorithm also identifies the different performance between dictionary data compression and statistical compression algorithms. In addition, the compression prior to encryption improves the efficiency of encryption and lead to the possible development of a multifunctional algorithm which could operate as both compression and encryption View full abstract»

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  • Buffer capacity analysis under the influence from timing jitter in SDH system

    Publication Year: 1996 , Page(s): 809 - 812 vol.2
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    The influence on the buffer capacity from timing jitter with different features has been analysed and the method of selection of the buffer capacity corresponding to a concrete communication system is proposed. Under multiple-sources of timing jitter, a stable result for the buffer capacity is given through the pointer adjustment process, bit accumulation in the buffer and and the jitter variations. This result shows that the buffer capacity can be reduced greatly compare to the conventional method View full abstract»

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  • Kohonen neural network based admission control in ATM telecommunication network

    Publication Year: 1996 , Page(s): 905 - 908 vol.2
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    In this paper, based on the Kohonen neural network, we propose a new method for call admission control in an ATM network. It avoids the contradiction between accurate training and a large number of training data in a BP neural network. It not only has a fast learning convergence rate, but also provides a high utilization rate of the channel and assures the quality of service in the simulation View full abstract»

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  • Information set decoding of generalised concatenated codes

    Publication Year: 1996 , Page(s): 764 - 766 vol.2
    Cited by:  Patents (2)
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    A generalised concatenated code (GCC) structure is proposed, which allows the construction of some binary linear codes which are optimum or close to the minimum-distance bounds. Either good overall coding rate or powerful error detection and correction can be achieved. Information set decoding is applied to these codes, and their performance is investigated View full abstract»

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  • Design of an ASIC for the ATM layer functions

    Publication Year: 1996 , Page(s): 723 - 726 vol.2
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    This paper describes the implementation of an ASIC, called ASAH-L (ATM subscriber access handler-logical), for the ATM-layer functions to develop network equipment in B-ISDN. ASAH-L is applicable to network-network interfaces or user-network interfaces and has F4 or F5 level OAM functions with real time processing defined by ITU-TS. Also it provides QOS and network parameter processing, a feature of the OAM. The interface between the ASAH-L and the physical layer functions is the UTOPIA level-1 interface defined by ATM Forum. ASAH-L has two interfaces, 53-octet and 56-octet architecture, for the AAL or ATM switch fabric functions. We have designed all the functions using VHDL. This ASIC, based on gate-arrays, uses 240,000 gates and is packaged in a 240-pin QFP (quad flat package). It is fabricated with 0.6 micron CMOS technology View full abstract»

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  • Zero-knowledge proof protocol of the isomorphism of graphs

    Publication Year: 1996 , Page(s): 1092 - 1093 vol.2
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    The discussion of the zero knowledge-proof protocol of the nonisomorphism of graphs (GNI) has appeared in many papers, but they are not complete zero-knowledge proof protocols at all. We will propose a complete zero-knowledge proof protocol, it implies that it is very difficult to design a secure zero-knowledge interactive proof protocols View full abstract»

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  • Software creation: an intelligent CASE tool experiment for switching software

    Publication Year: 1996 , Page(s): 961 - 964 vol.2
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    This paper reports on an automatic software design system used for a switching control system. The design knowledge is gained from diagrams produced by a CASE tool during the initial human design, is stored in each corresponding expert system unit, and is reused for reproducing the design. The design procedure consists of splitting a call process, inserting tasks and detailing. Various considerations for implementing the system in an intelligent CASE tool are discussed View full abstract»

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  • Alternative architectures for pulse stuffing synchronizers

    Publication Year: 1996 , Page(s): 813 - 816 vol.2
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (268 KB)  

    It is shown that the jitter produced by pulse stuffing synchronizers, used in digital transmission networks, can be decreased by using improved SNR Σ-Δ modulator circuits. For example, the technique of adaptive threshold modulation which is widely used in SONET/SDH synchronizers is shown to be such a circuit. The performance of these circuits can be further improved by the use of additional circuitry but maintaining their stability becomes a problem. This paper proposes stable alternative modulator architectures which are suitable for synchronizers. The performance of the proposed circuits is compared with the existing techniques View full abstract»

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  • Code phase assignment DS/CDMA communications for indoor wireless Rician multipath fading channels

    Publication Year: 1996 , Page(s): 1106 - 1109 vol.2
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    The technique of using a single basic signature sequence for the DS/CDMA system was investigated. All users have their sequences differing by cyclic phase shifts from a basic signature sequence. The technique is called code phase assignment (CPA). Yip and Ng (see IEEE/VTS 44th Vehicular Technology Conference, vol.3, p.1586, 1994), have shown that the CPA DS/CDMA technique yielded better performance over conventional DS/CDMA communications by a substantial reduction of the multiple access interference (MAI) and the multipath interference (MI) for a simplified channel model. This paper further investigates its performance in the indoor Rician multipath fading channel. A comparison with a conventional DS/CDMA system is made and the effect on the change of the system parameters is investigated. A higher multiple access capacity over a conventional DS/CDMA is demonstrated. CPA could reduce the effort of exhaustive search for sequences which makes it suitable for indoor applications View full abstract»

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  • An ATM switching system for broadband network

    Publication Year: 1996 , Page(s): 727 - 730 vol.2
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    The ATM (asynchronous transfer mode) network is regarded as effective for a multimedia telecommunication environment that enables highspeed and broadband communication. This paper reports the development of the FETEX-150 ESP(enhanced switching platform) which has been designed as an ATM switch in a public broadband network. To track the latest ATM standards and trends, a simple, scaleable, and open architecture was set forth for the FETEX-150 ESP design target at the beginning of the system design. This paper describes design concept and system architecture of the FETEX-150 ESP system from the hardware and software design viewpoint. Also, this paper describes traffic management, system features and operation and maintenance features in the FETEX-150 ESP View full abstract»

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  • A new preplanned self-healing scheme for multicast ATM network

    Publication Year: 1996 , Page(s): 888 - 891 vol.2
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (312 KB)  

    We study several backup path building schemes for multicast tree in self-healing ATM networks. Point-to-point link and path protection schemes are extended and modified for point-to-multipoint connection in ATM networks. A new scheme that modified from link protection and taking the advantage of the special structure of multicast tree is proposed. To minimize the spare capacity usage, several integer linear programming formulations are formulated and solved. After evaluating several test cases, we conclude that the new proposed theme has a good efficiency in the spare capacity usage and a fast restoration time View full abstract»

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  • A time code division multiple access (TCDMA) system proposal for indoor wireless communications

    Publication Year: 1996 , Page(s): 1094 - 1097 vol.2
    Cited by:  Papers (1)
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    Indoor environments for mobile radio communications provide special challenges due to the physical characteristics of the radio wave propagation. A hybrid access scheme (combining the advantages of both TDMA and wideband CDMA) called time code division multiple access (TCDMA) is proposed and investigated for indoor wireless communications. The indoor radio channel is modeled in terms of channel impulse responses by taking into account various indoor measurement results. Various simulation methods are used to reduce the computational complexity and to ensure the result accuracy. The simulation results of the system performance reveal the capability and the capacity of TCDMA in a typical indoor cell modeled as a multipath fading radio channel View full abstract»

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  • Performance analysis of finite output buffer ATM switch with Bernoulli arrival of two priorities

    Publication Year: 1996 , Page(s): 965 - 969 vol.2
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    A theoretical queue model of an ATM switch with Bernoulli arrivals of two priorities and finite output buffer capacity is developed. The average queue size, the loss probability of packets and the average waiting times are considered. Finally, a computer simulation proved the results of the analysis View full abstract»

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  • Image quality estimation in subband coding techniques based on human visual system

    Publication Year: 1996 , Page(s): 651 - 653 vol.2
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    This paper seeks to provide image quality estimation in subband coding techniques based on the human visual system. Subband coding techniques using differential pulse code modulation and the discrete cosine transform with some practical results are demonstrated. A simple objective measure for image quality is recommended View full abstract»

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  • Carrier specific routing for international switched transit service

    Publication Year: 1996 , Page(s): 866 - 869 vol.2
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    This paper presents a new network routing architecture for transit providers to allocate international switched transit service (ISTS) calls to a destination country based on the routing preference of the originating carriers. The new routing architecture is named carrier specific routing for international switched transit service (ISTS-CSR). An originating carrier would be able to specify its routing preference and traffic distribution pattern of its transit traffic to any given receiving country. Upon receipt of an international transit call, an originating switch of the transit provider would access a programmable database and retrieve the routing instruction specified by the originating carrier for the terminating country. In this manner, a terminating carrier can be selected to receive the transit call based on the routing preference previously specified by the originating carrier View full abstract»

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  • A reduced state Viterbi algorithm for multiuser detection in DS/CDMA systems

    Publication Year: 1996 , Page(s): 1102 - 1105 vol.2
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    Code division multiple access (CDMA) has attracted considerable attention in digital cellular mobile and personal communications. We propose a novel multiuser detector based on the reduced state Viterbi algorithm. It partitions the total K users into G groups according to their power strengths and interference levels, which reduces the computational complexity per binary decision from O(2K-1) to O(G*2KG-1/) for asynchronous DS/CDMA systems in AWGN. Theoretical analyses and simulation results are presented to demonstrate the significant performance improvement over the successive interference canceler (SIC) View full abstract»

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  • Performance analysis of an ATM cell multiplexer with MMPP input and a neural connection admission control approach

    Publication Year: 1996 , Page(s): 916 - 919 vol.2
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    ATM will be used to implement the BISDN. Because the cells of individual calls are combined in a statistical fashion, congestion may occur at multiplexers and switches in ATM networks. Understanding the queueing behaviour and the cell loss performance of ATM networks is very important for switch design, buffer dimensioning, and developing congestion control strategies. We study the performance of a finite-buffered statistical multiplexer with MMPP input. An exact analysis of the MMPP/D/1/K queue is carried out, yielding the loss probability. A supervised neural network is used for QOS estimation in admission control schemes so as to comply with ATM real time requirements. The inputs to the neural network are link statistics that are computationally easy to obtain and yield a good description of the aggregate link traffic. The neural network target QOS is derived by an accurate MMPP/D/1/K model to allow for a high utilization of network resources View full abstract»

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  • Blind equalization and its application to the PACS system

    Publication Year: 1996 , Page(s): 841 - 844 vol.2
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    High speed data transmission has become an important issue in mobile wireless communications. However, multipath propagation in wireless channels causes dispersion of the transmitted signals. We present a strategy to equalize the short burst without using a training sequence. This method is suitable for low-overhead TDMA systems such as PACS whose frame is very short. Different kinds of blind equalization algorithms are discussed and the simulation results indicate that the proposed method is feasible. We present the system model including the PACS system parameters and frame structure, and propose methods to equalize the radio channels using short sequences View full abstract»

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  • Delay-throughput comparison of single and multi-channel slotted ALOHA networks

    Publication Year: 1996 , Page(s): 934 - 937 vol.2
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    In networks where stations are equally likely to transmit to one another, simple slotted ALOHA is not an appropriate form of multiple access protocol as messages meant for different stations can collide in the common channel. In this paper the performance of a single channel slotted ALOHA network is compared to that of a CDMA ALOHA network where each station is assigned a different spreading code with which to receive messages, and thus effectively possesses its own private `virtual channel' View full abstract»

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