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Communications, 1997. ICC '97 Montreal, Towards the Knowledge Millennium. 1997 IEEE International Conference on

Date 12-12 June 1997

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  • Proceedings of ICC'97 - International Conference on Communications

    Publication Year: 1997
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  • Conference Author Index

    Publication Year: 1997 , Page(s): 1745 - 1750
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  • A generalized grouping and retrieval scheme for stored MPEG video

    Publication Year: 1997 , Page(s): 1674 - 1678 vol.3
    Cited by:  Papers (5)
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    MPEG, in addition to being an international standard, is currently the most popular coding scheme for stored video. For several applications that require stored video, such as video-on-demand, it is advantageous to group MPEG frames into segments. Retrieving segments instead of individual frames can result in a more efficient use of disk retrieval resources and consequently, in the support of a larger number of users and in a more cost-effective system. Depending on the value of parameters such as desired user quality of service, size and cost of required buffers, number of disks to stripe a segment across, etc., a certain segment length (defined as the number of frames per segment) may be preferred over others. In this paper, we propose a generalized grouping scheme that may be used to achieve any desired segment length. Properties of such a grouping scheme and formulae that may be used to achieve such a grouping have been provided. Since a segment is an atomic unit of video retrieval, retrieval of some segments is skipped during fast playback. Some frames belonging to retrieved segments may be discarded due to the unavailability of other frames necessary for their decoding. Tradeoffs between different kinds of fast playback (i.e., the choice of skipped segments) and the number of discarded frames is discussed View full abstract»

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  • Performance of the COFDM systems with waveform shaping

    Publication Year: 1997 , Page(s): 1241 - 1245 vol.3
    Cited by:  Papers (2)
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    This paper explains the advantages of using a method for waveform shaping in COFDM. It is shown that such data shaping decreases the side lobes of the transmitted signal and minimizes the need for a guard band between OFDM systems. Classical OFDM systems based on DFT make use of a guard interval in order to improve the performance in multipath fading channels. A part of the loss due to the power transmitted during the guard interval can be compensated efficiently by the waveform shaping which is proposed. In the presence of both AWGN and multipath fading the bit error performance of the proposed system and the classical COFDM systems are compared. Digital video broadcasting is used as an example View full abstract»

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  • Smoothing algorithms for the delivery of compressed video

    Publication Year: 1997 , Page(s): 1330 - 1334 vol.3
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    The transport of compressed video without loss of picture quality requires the network to support large fluctuations in bandwidth requirements. This paper introduces a lossless smoothing algorithm designed to satisfy any given set of buffer and delay constraints for both stored and live video applications with the goal of minimizing the number of rate changes and maximum rate. The algorithm is shown to be effective in smoothing bursty bit streams as illustrated by the experimental demonstration of MPEG encoded video View full abstract»

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  • Efficient time slot assignments for TDM multicast switching systems

    Publication Year: 1997 , Page(s): 1366 - 1370 vol.3
    Cited by:  Papers (3)
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    This paper focuses on designing efficient multicast time slot assignment (MTSA) algorithms for TDM switching systems, Based on a packet compatibility matrix, the MTSA can be transformed to the well-known graph-coloring problem. We show that the MTSA problem is NP-complete. A lower bound on the frame length of a multicast time slot assignment is then found to be the clique number of the MTSA equivalent graph. Two efficient MTSA algorithms, called the contention-based ordering (CBO) algorithm and the hybrid ordering algorithm, are proposed. Their performance is compared with the three existing algorithms and the lower bound through extensive simulations. We found that the CBO algorithm, which has one of the lowest computational complexities, gives the best performance among all five algorithms studied. The average frame length generated by the CBO algorithm is within 1% above the lower bound. We also show that (i) the previously reported DAC algorithm has the poorest performance despite its highest complexity, and (ii) the previously reported CCBO algorithm has only a comparable performance to the simple greedy algorithm View full abstract»

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  • A dynamic reservation protocol for multi-priority multi-rate data services on GSM networks

    Publication Year: 1997 , Page(s): 1261 - 1265 vol.3
    Cited by:  Papers (1)  |  Patents (2)
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    This paper presents a new media access control protocol for multi-priority multi-rate data services on GSM networks. In this protocol, which we named dynamic reservation protocol, data terminals can get their uplink channels through contention-free reservation. Therefore this protocol can achieve very high channel utilization efficiency and can significantly improve the service performance under heavy traffic load. The reservation scheme can adapt to traffic variations, by dynamically changing the transmission cycle length. Simulation results show that this protocol offers significantly better delay/throughput performance when compared to other protocols proposed in the literature. Since this protocol is built on the top of the GSM physical layer, its implementation should be very straight forward View full abstract»

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  • Moments of the first passage time to overload for a buffered statistical multiplexer

    Publication Year: 1997 , Page(s): 1689 - 1693 vol.3
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    We consider the first passage to overload for a buffered statistical multiplexer loaded with N identical binary on-off sources. First passage times to overload are related to the characterization of congestion imminence which in turn is crucial in the design of effective congestion control algorithms for delay sensitive services in broadband wide area networks. We give the moments of the first passage time to overload as solutions of a set of linear first order ordinary differential equations. Furthermore, adapting the methodology developed by Anick, Mitra and Sondhi (1982) we express the moments of the first passage time to overload in a spectral expansion form, involving the system's eigenvalues. Numerical results for the first two moments are presented View full abstract»

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  • Real-time cell loss estimation for ATM multiplexers with heterogeneous ON/OFF sources

    Publication Year: 1997 , Page(s): 1679 - 1683 vol.3
    Cited by:  Papers (2)
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    We are concerned with a real-time quality of service (QOS) estimation method for ATM statistical multiplexers with heterogeneous ON/OFF sources. We propose a real-time modeling method for the superposed traffic by a two-state MMPP by approximating the density function of aggregate cell arrival rate as a Bellows-like Poisson process. We also investigate a real-time calculation of the waiting time distribution for MMPP(2)/D/1 system to consider an upper bound of the cell loss ratio (CLR) for the finite-buffer system. Numerical examples show that the proposed QOS estimation method gives a good estimation of CLR View full abstract»

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  • Mapping wander in SONET/SDH adaptive threshold modulation pointer processors

    Publication Year: 1997 , Page(s): 1587 - 1591 vol.3
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    There are three types of pointer processors in synchronous optical network (SONET) and synchronous digital hierarchy (SDH) networks: traditional fixed threshold, uniform and adaptive threshold modulation. Fixed threshold pointer processors produce gapped pointer sequences as a result of the periodic effects of the SONET/SDH overhead bytes. These gapped pointer sequences cause wander when SONET/SDH carries PDH payloads. Uniform pointer processors smooth the gapped pointer sequences caused by the STM-N, AU and TU overhead bytes. Adaptive threshold modulation pointer processors (ATM-PPs) can also exhibit gapped pointer effects. This paper compares the wander from a gapped ATM-PP and the wander from a proposed uniform ATM-PP. The results indicate that this novel technique reduces wander View full abstract»

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  • Architecture for restorable call allocation and fast VP restoration in mesh ATM networks

    Publication Year: 1997 , Page(s): 1158 - 1163 vol.3
    Cited by:  Papers (1)  |  Patents (9)
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    This paper presents an architecture for restorable call allocation and fast virtual path (VP) restoration in mesh ATM networks. In this architecture, virtual working and spare capacities needed for call allocation and restoration are reserved and released dynamically on a call-by-call basis at the time of call admission and termination. The architecture does not require advance assignment of spare and working capacities. To shorten the call processing delay, this is done in a parallel-distributed fashion. To provide restorable call allocation, parallel-distributed call processing algorithms of the sender-chooser type are suggested. The algorithms integrate on the call level virtual bandwidth allocation, virtual spare capacity assignment with fixed, alternate, or state-dependent routing. Each routing scheme leads to a particular tradeoff between call processing complexity, call setup delay, and bandwidth efficiency. For each pair of nodes, two sets of VPs are provisioned. The first is a working VP (WVP) set, to be used for call allocation during the normal operation. The second is a spare VP (SVP) set, to be used for VP restoration in the event of failure of network elements (NE). Each SVP protects a preassigned subset of the node pair WVPs. Each SVP is selected to be link/node disjoint from the WVPs that it is assigned to protect. This assures protection of the WVP set by a small number of SVPs. Since SVPs are preset and appropriate virtual spare capacities are reserved in advance, the architecture guarantees full restorability and provides very fast restoration. The restoration is done on the VP level in a self-healing manner. The suggested architecture requires only local information to be maintained at each node View full abstract»

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  • A scalable, dynamic multicast routing algorithm in ATM networks

    Publication Year: 1997 , Page(s): 1361 - 1365 vol.3
    Cited by:  Papers (3)  |  Patents (1)
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    In this paper, we present a scalable dynamic multicast routing algorithm based on a dynamic Steiner tree approach. First, we analyze a hierarchical multicast routing algorithm which introduced the use of core nodes in each peer-group to support multicasting under the private network-network interface (PNNI) framework. Based on this analysis, we conclude that finding near-optimal multicast trees in each peer-group is important. Our proposed algorithm produces improved results by computing better multicast trees within each peer-group. This scheme also eliminates the dependency of core node selection, on the quality of overall multicast tree generated. We compare the two schemes based on simulations on several randomly generated graphs of size ranging from 115 to 170 nodes. Based on these simulations, we show that our algorithm performs 35% better than the hierarchical algorithm. Our algorithm is scalable, allows incorporation of fault-tolerance and can easily be extended to incorporate a QoS criterion in routing View full abstract»

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  • A MMSE interpolated timing recovery scheme for the magnetic recording channel

    Publication Year: 1997 , Page(s): 1625 - 1629 vol.3
    Cited by:  Papers (12)  |  Patents (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (376 KB)  

    Advances in VLSI technology permit the use of interpolated timing recovery (ITR) as a replacement for the conventional VCO-based phase lock loop. Fully digital ITR has the advantage of lower cost and higher stability. In this paper, we present an interpolated timing recovery scheme that requires almost no oversampling, which should be suitable for high-speed storage channels View full abstract»

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  • A simple packet combining technique in frequency-hopped spread-spectrum multiple access communication networks

    Publication Year: 1997 , Page(s): 1207 - 1211 vol.3
    Cited by:  Patents (2)
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    In this paper, we propose a simple packet combining scheme in frequency-hopped spread spectrum multiple access (FH/SSMA) communication networks, which makes a tone-by-tone logical AND operation on the previously combined packet and the currently received (retransmitted) packet. The packet error probability is analyzed in the presence of multiple access interference (MAI) with AWGN or Rayleigh fading. It is found that the number of simultaneous users can be increased almost by a factor of two as compared to the conventional scheme, and the performance improvement becomes more significant, as the number of combined packets is increased. It is also found that for the packet error probability of 10-2 and M=8, a 2-4 dB gain in Eb /N0 can be obtained over the conventional scheme in the AWGN and Rayleigh fading channels, and the gain increases as M increases View full abstract»

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  • Minimizing maximum logical link congestion in packet switched optical networks

    Publication Year: 1997 , Page(s): 1298 - 1302 vol.3
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    We consider the problem of designing logical optical network topology for a given physical topology (or fiber layout) and a given traffic demand matrix between the end-users. Traffic between the end-users is carried in a packet-switched form and the objective of our logical topology design is to minimize the maximum congestion on the logical links in the logical topology. The logical links are realized by wavelength continuous paths or between end-users and they are routed via wavelength-selective routers. Note that a topology with lower maximum link congestion will allow its traffic demand matrix to be scaled up by a larger factor. In the logical topology, each node is equipped with a limited number of optical transceivers, hence logical connections cannot be set-up between every pair of nodes. In this paper we present an analytical model for obtaining the maximum and average logical link loads for a given logical network and traffic demand matrix. The model is confirmed via simulation. A heuristic algorithm for constructing a logical topology that reduces maximum logical link congestion is also presented View full abstract»

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  • An adaptive connection admission control scheme for ATM networks

    Publication Year: 1997 , Page(s): 1153 - 1157 vol.3
    Cited by:  Papers (2)  |  Patents (3)
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    A new adaptive connection admission control scheme is proposed. The aggregate statistics of all calls in progress are continuously measured and new calls are considered as CBR at their peak during certain warming up period. The main features of our proposed CAC scheme are (1) an adaptive mechanism which updates the warming up period based on the traffic conditions, (2) an accurate mechanism to predict cell loss, and (3) a simple and conservative way to consider call departures. We demonstrate by simulation that the scheme is more efficient than several other schemes View full abstract»

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  • Reactive bandwidth arbitration for priority and multicasting control in ATM switching

    Publication Year: 1997 , Page(s): 1724 - 1728 vol.3
    Cited by:  Patents (1)
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    A new service scheduling scheme, reactive bandwidth arbitration (RBA), is proposed as an effective way to arbitrate the contention among priority classes or between unicast and multicast services in ATM switching. The RBA scheme integrates two previously proposed concepts: bandwidth allocation and reactive arbitration. In, RBA, guaranteed bandwidth is allocated to a connection at call set up based on the traffic characteristics and service requirements, while the arbitration of cell delivery takes into account the queue status to react to traffic fluctuation. Through simulation, we found that by bandwidth allocation, a set of queue threshold levels can be obtained to provide a good approximation to the desired delay performance. Furthermore, around this initial configuration, a linear relationship between the queue threshold and the resulting delay performance can be established to fine-tune the configuration parameters for the desired delay performance. Similar effects were observed as the RBA scheme was applied to arbitrate the contention between unicast and multicast connections in a shared buffer ATM switch. The proposed RBA scheme was incorporated in a queue manager chip for an 8×8 shared buffer ATM switch with four priority classes per port and link rate at 622 Mbps. The chip has 130 k gates in a chip area of 137.88 mm2 and operates at 25 MHz View full abstract»

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  • Output-buffer ATM packet switching for integrated-services communication networks

    Publication Year: 1997 , Page(s): 1684 - 1688 vol.3
    Cited by:  Papers (8)
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    In this paper, we give an overview of the basic design principles and trade-offs of output-buffer ATM switching. Output-buffer switches give optimal performance in terms of offering bandwidth guarantees to individual flows. Bandwidth scheduling and memory bandwidth requirements are also described View full abstract»

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  • Error concealment, early re-synchronization, and iterative decoding for MPEG-2

    Publication Year: 1997 , Page(s): 1654 - 1658 vol.3
    Cited by:  Papers (3)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (748 KB)  

    For the digital transmission of TV the video-signal will be highly compressed with the MPEG-2 source coding algorithm. The MPEG-2 source coded stream is very sensitive to channel disturbances due to variable length coding. A single bit error may result in error propagation, therefore, it will cause a high degradation of picture quality. Hence, error concealment techniques or iterative decoding techniques might be required at the receiver. The aim of this article is to study different techniques for handling channel errors at the receiver side. The first way is to apply error concealment techniques after source decoding. For P- and B-pictures, the inherent motion vectors can be used for temporal error concealment (TEC) which yields very good results. However, in I-pictures no motion vectors exist for TEC. Furthermore, the spatial error concealment (SEC) techniques suffer from the non existence of neighbored macroblocks (MBs) because of the re-synchronization at the slice level. Therefore, another technique, which is called early re-synchronization, in combination with an enhanced error detection technique is investigated in this article. With this technique most of the correct received data can be exploited for error concealment and the quality of service mainly in I-pictures will be improved. A second way for handling channel errors is to apply iterative channel decoding. With this, the error correction capability of the channel decoding part can be improved and less residual errors will occur in the bitstream View full abstract»

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  • Heuristic algorithms for configuration of the ATM-layer over optical networks

    Publication Year: 1997 , Page(s): 1164 - 1168 vol.3
    Cited by:  Papers (2)
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    A general model and algorithms are presented for the optimal configuration of the ATM layer on top of mostly optical networks. The topology of the physical layer is assumed given with the predefined paths for each node-pair. The output is the size of required ATM switches, and the configuration of both, ATM and optical switches. The obtained result is optimal in the sense of reduced resource usage on ATM level, i.e., reduced electrical processing, subject to capacity and connectivity constraints. The results are derived for WDM networks and generalized for networks with optical cables where multiple fibers per cable are used (space division multiplexing). The idea of layered design is also introduced. Since the problem is discrete by nature with multiple local optima and constraints, non-deterministic constrained discrete global optimization algorithms are used. The running time and the probability of finding global optimum are compared for these algorithms View full abstract»

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  • An adaptive array for wireless communication systems with frequency selective multipath fading using high order statistics processing

    Publication Year: 1997 , Page(s): 1356 - 1360 vol.3
    Cited by:  Papers (1)
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    A linear high-order statistics based method is proposed to mitigate the performance degradation caused by multipath RF propagation in a mobile radio communication system using a linear antenna array in the base station receiver. The method is based on noncausal autoregressive modeling. It is shown that a set of linear equations (involving only cumulants of the received baseband digitized signal) can be obtained to perform noniterative deconvolution. An efficient adaptive algorithm is proposed View full abstract»

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  • Novel multilevel modulation scheme for high capacity digital wireless access

    Publication Year: 1997 , Page(s): 1527 - 1531 vol.3
    Cited by:  Papers (2)
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    This paper proposes a novel multilevel modulation scheme called amplitude ratio and phase modulation (ARPM). This scheme employs amplitude ratio and differential phase between two sequential transmission symbols as modulating signals. In this scheme, two amplitude ratios, one less than 1 and the other greater than 1, are allocated to one transmission symbol to avoid the conditions under which the modulated wave amplitude diverges to infinity or converges to zero. Demodulating an ARPM wave is feasible without precise level detection or accurate coherent detection even in a fast fading environment. Suitable mapping for transmission signal points in ARPM and suitable level decision for received ARPM wave are discussed. The static BER performance and the equivalent ATPC effect in ARPM are evaluated. The results confirm that ARPM is suitable for high capacity digital wireless access systems such as future broadband multimedia wireless access systems View full abstract»

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  • Quality of service and overload concepts in wireless multimedia networks based on cellular ATM

    Publication Year: 1997 , Page(s): 1458 - 1462 vol.3
    Cited by:  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (384 KB)  

    The need for wireless ATM networks is motivated by an anticipated demand for wireless extension of integrated multimedia services. This wireless extension gives the mobile access part of a backbone ATM-based broadband services fixed network (B-ISDN) for future integrated communications. One of the major mobility-related functions, is connection hand-off when a mobile terminal roams between radio cells. Using the virtual connection tree already proposed for high-speed cellular radio networks based on an ATM backbone, this paper presents an implementation of the Quality of Service (QoS) and overload concepts in a wireless ATM system. Simulation results are presented for a voice and multimedia scenario View full abstract»

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  • Multipoint-to-point ABR service in ATM networks

    Publication Year: 1997 , Page(s): 1185 - 1190 vol.3
    Cited by:  Papers (7)  |  Patents (1)
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    Efficient support for scalable multipoint-to-multipoint (mpt-mpt) communication in ATM has recently become a hot topic of discussion at the ATM Forum. Previously, we presented a new class of efficient switch algorithms for point-to-multipoint (pt-mpt) ABR service that deliver high performance in terms of fairness and link utilization and are significantly simpler to implement than other proposed protocols. However, the more challenging problem of providing bidirectional mpt-mpt ABR service has not been addressed before. While a number of key issues have been resolved in unidirectional pt-mpt ABR service, no satisfactory solution for multipoint-point (mpt-pt) ABR service is known. In this paper, we propose new efficient mpt-pt ABR mechanisms that can interoperate with existing standards for ABR service and provide a truly transparent and scalable solution to multipoint communication in ATM. We present simulation results to illustrate that our proposed ABR schemes provide high link utilization and fair bandwidth allocation in a mpt-pt connection for heterogeneous sources with different data rates View full abstract»

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  • An analysis tool for predicting performance in an all-optical time division multiplexing data switch

    Publication Year: 1997 , Page(s): 1325 - 1329 vol.3
    Cited by:  Papers (1)
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    Performance of shared memory architectures for optical switching is typically obtained by simulation, and in low packet loss regions is subject to statistical error or excessive computer run times. To obtain a reliable measure of performance, a Markov chain with a small number of states has been developed to model the switch's behavior. This reduced chain is derived from a full Markov chain which more directly models the switch. Equations to count the number of states for both Markov chains are derived. Packet loss results derived from the reduced Markov chain are compared with simulation results View full abstract»

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