bluuebunny/crossref_metadata_2025_split huggingface dataset:
Input/Output Buffered Replicated Banyan Networks for Broadband Switching Applications
Authors: Corazza Giorgio , Raffaelli Carla 
Published: September 2008

AbstractA switching architecture suitable for broadband applications, employingR‐replicated Banyan interconnection networks with input and output buffering, is presented. Various solutions for traffic management among the replicated networks and buffer allocation are considered and their performances evaluated by means of an analytical model based on Markov chain representations of input and output buffers. The main results regard evaluation of maximum throughput, delay and packet loss probability by varying operating and design parameters. It has been shown that our architecture satisfies broadband switching operating requirements, with a suitable choice of design parameters, and also performs better than other architectures presented in literature. These considerations suggest that the investigated architecture is very interesting for the implementation of a broadband switch and should be compared with other solutions in an economic perspective.
Analysis of Global‐List Decoding for Convolutional Codes
Authors: Zigangirov Kamil , Osthoff Harro 
Published: September 2008

AbstractDepartment of Information Theory University of Lund Box 118 S‐ 221 00 Lund ‐ SwedenIn this paper we consider the global‐list decoding algorithm for convolutional codes. We introduce the notion of the L‐list minimum distance and prove lower and upper bounds for if. Furthermore, we derive lower and upper bounds for the decoding error probability of the global‐' list decoding.
ISCP (ISDN Signalling Control Part): the Best Candidate for the Target Broadband‐ISDN Signalling Protocol
Authors: Paglialunga Alberto , Siviero Maurizio 
Published: September 2008

AbstractThis article is focused on the signalling protocol for future Broadband ISDN (B‐ISDN). A brief description of the current ISDN signalling system is given, highlighting some of its limits which make this system unsuitable to be applied in a B‐ISDN environment. The paper recalls the advantages of the Call Control and Bearer Control functional separation which is needed to handle complex telecommunication services as those offered by a broadband network. The main requirements of the future B‐ISDN are presented as far as network signalling is concerned and an hypothesis of protocol is outlined. The best protocol candidate to satisfy the B‐ISDN requirements is the ISDN Signalling Control Part (ISCP). It is based on the Application Layer Structure (OSI layer 7) principles, which are briefly described. Furhermore, the alternative use of TCAP and S‐ACSE to handle establishment and control of associations is outlined. Finally, an example of procedure to establish Call Control and Bearer Control associations in an ISCP environment is provided.
Data Flow Through a Double Process System
Authors: Burton Fraser , Gell Michael 
Published: September 2008

AbstractA simple model of an element in a data communications network has been investigated. It is shown that the system exhibits a rich dynamical behaviour which under certain conditions may lead to a substantial and sometimes persistent degradation in its performance. Simple guidelines are established for specifying the conditions under which such exotic behaviour, eg: periodic and aperiodic oscillations, can be avoided in order to guarantee reliable and optimal operation of the system. The model is extended to consider multi‐process/processor systems.
A Multicarrier El‐HDSL Transceiver System with Coded Modulation
Authors: Chow Peter S. , Al‐Dhahir Naofal , Cioffi John M. , Bingham John A. C. 
Published: September 2008

AbstractIn this paper, we present a trellis‐coded multicarrier transceiver system, known as Discrete Multitone modulation, for the application of transmitting digital data at the El rate of 2.048 Mbit/s over existing copper telephone lines. The service of El‐HDSL (El‐rate High‐speed Digital Subscriber Lines) is currently being studied by ETSI for future deployment in Europe. Because of severe crosstalk and additive white Gaussian noise (AWGN) encountered in El‐HDSL, the application of a powerful trellis code is highly desirable to ensure reliable system performance, with a required bit‐error‐rate (BER) of no more than 10−7, at the desired El data rate. Detailed descriptions of the DMT transmitter and receiver structures are given, and projected performance results, both with and without the addition of a trellis code, are presented. Because of the different transmission environments encountered in the various countries in Europe, we have performed our computer simulation on both British and German (1) copper twisted‐pairs. We find that with the addition of Wei's powerful 4‐D 16‐state trellis code, we can achieve the El rate with a positive margin over all loops tested using either one or two sets of twisted‐pairs only, depending on the particular transmission scenario.
Block‐Coded Modulation Using Reed‐Muller Component Codes and Multistage Decoding
Authors: Karam Georges , Paxal Vendela , Sari Hikmet 
Published: September 2008

AbstractUsing a 2‐step partitioning of the signal constellation and Reed‐Muller component codes, we construct block‐coded modulation (BCM) schemes that achieve an asymptotic coding gain close to 6 dB. The component code associated to the first partitioning step is a distance‐4 or a distance‐8 Reed‐Muller code, and the code associated to the second partitioning step is a simple parity‐check code. We investigate BCM schemes with square signal constellations and a fractional number of information bits per symbol as well as BCM schemes with circular signal constellations and an integer number of information bits per symbol. We use multistage decoding with a Viterbi algorithm for the first component code using the trellis description given by Forney. Our results indicate that with short block lengdis, these BCM schemes compare favorably with trellis coded modulation (TCM) of similar complexity. Due to the rapid increase of the error coefficient, however, they lose their advantage as the block length increases.
Trellis Coded 16‐QAM for Fading Channels
Authors: Du Jun , Vucetic Branka 
Published: September 2008

AbstractFast growth in digital communications leads to increasing needs for high data transmission rates. Such needs can be met by bandwidth efficient modulation schemes. In this paper, a trellis coded. 16‐QAM scheme over flat fading channels is considered. Through analysis, new bounds on error rate performance of the scheme are derived. A set of new criteria for code design based on these bounds are formulated and used to construct new trellis 16‐QAM codes for fading channels. One of the key parameters in code design is the minimum product distance. An algorithm for computing the minimum product distance and its multiplicity is proposed. The algorithm is applied in search for optimum trellis codes. The performance of 16‐QAM TCM schemes with ideal channel state information (CSI) on Rayleigh fading channels is evaluated by simulation. The results show the proposed codes achieve significant improvements relative to the best known 16‐QAM modulation codes as well as 16‐PSK codes.
Millimetre Wave Short Range Communications for Advanced Transport Telematics
Authors: Andrisano Oreste , Chiani Marco , Tralli Velio , Frullone Mario , Moss Colin R. 
Published: September 2008

AbstractThis paper presents the results of a research programme to investigate short range millimetre wave communications links for road transport telematics applications. The work was carried out by the University of Bologna, the Fondazione U. Bordoni and Marconi Radar and Control Systems Limited. Financial support was provided by PROMETHEUS programme, which is itself a EUREKA research project and the ECC DRIVE programme.The paper provides a theoretical assessment of the effects of multipath as applied to millimetre wave vehicle‐to‐vehicle and vehicle‐to‐roadside communications links. A digital link, based on phase shift keying, is assumed. Performance improvements resulting from the use of both antenna diversity and coding are assessed.
Address‐Predictive Vector Quantization of Images by Topology‐Preserving Codebook Ordering
Authors: Poggi Giovanni 
Published: September 2008

AbstractAddress vector quantization is a recently proposed image coding technique based on vector quantization (VQ) which exploits the interblock dependence by jointly encoding groups of VQ addresses. In this paper, by further developing the idea of address encoding, a new image coding technique is proposed. It is based upon the design of an ordered VQ codebook such that co‐devectors which are similar to each other have close addresses. As a result, the performance in terms of bit‐rate is very close to that of Address VQ, but much lower computational complexity and memory storage are required.
Letter: PLL Bandwidth Impact on Slave Clock Output Short Term Stability
Authors: Brugia Odoardo , Carbonelli Marco , Seta Domenico De , Perucchini Daniele 
Published: September 2008

AbstractStarting from a fairly general slave clock reference model, a relationship between phase noise power spectral density and output stability expressed in terms of TIE, is used to evaluate. via numerical integration, actual clock behaviour in the case of SDH equipment clocks. This approach may prove very useful in designing synchronization for SDH based transport networks.
Timing Considerations for Optical Fibre PPM
Authors: Cryan Robert A. , Elmirghani Jaafar M. H. , Clayton F. Mike 
Published: September 2008

AbstractDigital pulse position modulation (PPM) has been shown to be an effective modulation format for the optical fibre channel. It is paricularly attractive as it can exploit the abundant mono‐mode optical fibre bandwidth to offer improved performance. The format is a discrete time modulation format wherein synchronisation at both the slot and the frame levels is vital. In this paper we derive an original analytic expression that predicts the spectral properties of optical fibre digital PPM on the basis of its cyclostationary random properties. We establish the conditions required to achieve both slot and frame synchronisation and further, we show that the system synchronisability can be optimised in terms of its parameters. In particular, we consider die effect of the pulse shape, modulation index and the data probability distribution on the spectral properties. Finally, we present original practical results measured on a 128‐ary PPM system and show that they are within 1 dB of those predicted by our analytic model. We conclude that optical fibre digital PPM synchronisation can be achieved and further, optimised, in terms of the major system parameters.
Letter: High Capacity Digital Radio With Trellis Coding
Authors: Baccetti Baccio , Taverna Marcello , Bellini Sandro , Saivini Giorgio 
Published: September 2008

AbstractIn this paper we analyze the performance of Trellis Coded Modulation (TCM) for high capacity digital radio. Some error correcting code is needed to comply with the low background bit error rates prescribed for this application, despite practical imperfections unavoidable in modems and nonlinear distortion of high power amplifiers. The redundancy that can be accepted is very limited, however, due to the strict bandwidth constraints.TCM schemes are very effective in conserving bandwidth. Therefore, they look very promising for digital radio applications.We analyze many aspects of TCM, including multidimensional schemes. We consider the performance of TCM in the AWGN channel and in multipath fading channels, and we evaluate the effect of nonlinear amplification. Finally, we consider decoder complexity.Significant coding gains can be obtained from codes of acceptable complexity. A good compromise between performance and complexity turn out to be 8‐state codes. The complete Viterbi decoder for these codes can be fully integrated on just one chip.As a typical application, a system transporting the first level of the Synchronous Digital Hierarchy (STM ‐ 1; 155.52 Mbit/s) operating on 30 MHz interleaved crosspolarized frequency arrangements is analyzed in detail.
Letter
Authors: Costamagna Eugenio , Fanni Alessandra , Maestrini Raoul 
Published: September 2008

AbstractIn this letter, we examine how the reliability of a telecommunication network depends on the redundancy of the number of edges, with respect to the minimum number of edges required to connect all the nodes,varying the failure probabilities associated with each edge. Typical reliability patterns can be recognized, which depend substantially on the network redundancy and on the mean value of the assumed probabilities, and simple heuristic strategies allow to obtain good reliability results by insertion of very small numbers of redundant edges. The main results are well represented in graphical form in Figs. 2 and 3, where network reliabilities are computed from randomly assigned link reliabilities, assuming gaussian and uniform distributions. Reliabilities performances can be easily lower and upper bounded, as a function of network .redundancy and link reliability distributions.
Integrated receiver structure of staged decoder and CCI canceller for CDMA with multilevel coded modulation
Authors: Saifuddin Ahmed , Kohno Ryuji , Imai Hideki 
Published: September 2008

AbstractThis work presents a direct sequence spread‐spectrum multiaccess (DS/CDMA) receiver that employs integrated structure of staged decoder and CCI (co‐channel interference) canceller, when multilevel coded modulation is used and the system undergoes fading channel. We exploit the attractive multistage decoding method of multilevel coding. Each stage decoding is jointly done with the data estimation process and thus replicas of CCI can be formed with high precision, which ultimately results in performance improvement without any additional decoding delay or circuit complexity. We have chosen appropriate multilevel 8‐PSK coded modulation schemes for the integrated receiver of staged decoder and CCI canceller in fading channels. Computer simulation results show the significant coding gain that can be achieved by the proposed scheme in comparison with the conventional scheme. The effect of estimation error as well as unequal power is also investigated.
Linear adaptive transmitter‐receiver structures for asynchronous CDMA systems
Authors: Rapajic Predrag B. , Vucetic Branka S. 
Published: September 2008

AbstractAn asynchronous code‐division multiple access (CDMA) system with adaptive transmitters and receivers is considered. It is assumed that the adaptive receiver and transmitter have no knowledge of the signature waveforms and timing of other users. The concept of adaptive transmitter is based on feedback information from the corresponding receiver. The information obtained from the receiver is used to calculate the optimum transmitter signature. The signatures are adaptively adjusted according to the MSE criterion during the training period as well as during data transmission. CDMA systems employing the adaptive transmitters in the presence of multiple access interference achieve the matched filter bound with no interference. The proposed CDMA system are tested by simulation over a channel with multiple access interference and additive white gaussian noise.
The performance of diversity combining for fast frequency hopped NCMFSK in rayleigh fading
Authors: Aaron Gulliver T. , Ezers Rolands E. , Barry Feistead E. , Wight James S. 
Published: September 2008

AbstractFrequency hopping (FH) spread spectrum is a well known technique used in communications systems to provide protection against interference such as jamming. With fast FH (FFH) (one or more hops per transmitted data symbol), powerful and robust methods for diversity combining have been developed as an additional jamming countermeasure. These same techniques can be applied to reduce the effects of multiple access interference, and so can be considered for civilian CDMA applications. Although the performance of a FFH communications system can be degraded considerably by fading, few results exist which show the effects of fading on the diversity combining process. In this paper, both analytic and simulation results are presented for several diversity combining methods in a Rayleigh fading channel, which is often considered to be the worst case. The performance of these combining methods in fading is compared with that in AWGN and multitone interference to determine which methods are effective against these degradations.
Realization of a passive broadband‐network termination 1 (B‐NT1) for the optical user‐network interface
Authors: Jahreis Oliver , Möller Olaf , Derr Frowin 
Published: September 2008

AbstractA new passive Broadband Network Termination 1 (B‐NT1) as an alternative to the active B‐NT1 for B‐ISDN is described which supervises the UB interface between B‐LT and B‐NT1. For this purpose, the B‐LT generates an additional pseudo noise (PN‐)signal which is reflected at the passive B‐NT1 and analysed by a correlation method in the B‐LT. The alarm flow between B‐LT and the B‐NT2 remains unchanged by introducing a new reflection alarm REFL in the B‐LT which is based on the evaluation of the correlation signal and describes the condition of the UB interface. The passive B‐NT1 concept offers a more economical alternative for the network operator to provide Operation and Maintenance (OAM) on the TB and UB interface.
Power and bandwidth efficient digital communication using turbo codes in multilevel codes
Authors: Wachsmann Udo , Huber Johannes 
Published: September 2008

AbstractThe recently proposed Turbo codes are applied to bandwidth efficient modulation schemes via multilevel coding. For this purpose, Turbo codes are extended for a wide range of fine tunable rates by puncturing. A straightforward derivation of iterative Turbo decoding and the concept of extrinsic information is presented. New design rules for multilevel codes with arbitrary component codes and codeword lengths are derived from information theory. Simulation results show that application of Turbo codes to properly designed multilevel coding schemes leads to digital transmission schemes with high power and bandwidth efficiency.
Capacity of channels with uncoded side information
Authors: Shamai Shlomo , Verdú Sergio 
Published: September 2008

AbstractParallel independent channels where no encoding is allowed for one of the channels are studied. The Slepian‐Wolf theorem on source coding of correlated sources is used to show that any information source whose entropy rate is below the sum of the capacity of the coded channel and the input/output mutual information of the uncoded channel is transmissible with arbitrary reliability. The converse is also shown. Thus, coding of the side information channel is unnecessary when its mutual information is maximized by the source distribution. Applications to superposed coded/uncoded transmission on Gaussian channels are studied and an information‐theoretic interpretation of Parallel‐Concatenated channel codes and, in particular. Turbo codes is put forth.
Small scale site diversity for satellite communications: 11.5 GHz propagation measurements and system applications
Authors: Lombardi Paolo 
Published: September 2008

Abstract“Small scale site diversity”, a well known antifading technique for satellite communications above 10 GHz, is considered in the paper. This technique takes advantage of the limited extension of heavy rain cells by replacing each earth station in a rainy area with two, or more, interconnected stations and using the earth‐satellite path less affected by fading.The statistical results are presented of a three years( 1986‐88) propagation experiment. The EUTELSAT‐I 11.5 GHz beacon signal rain attenuations on the diversity paths between the satellite and two earth stations located in the Rome area about 16 km apart were measured. The experiment results are synthetically expressed in terms of the “diversity gain”, showing that, with an ideal diversity switching system, the fade margin can be reduced by an amount equal to 65‐80% of the margin needed in the single station case. On the ground of these results, reasonably extended to a different situation, an example is given of an underdimensioned link which can be made compliant to high availability requirements enabled by the use of the small scale site diversity technique.
Learning the compatibility matrix for adaptive resource management in cellular radio networks
Authors: Duque‐Anón Manuel , Koch Patrik , Kunz Dietmar , Rüber Bemhard , Ullrich Meinhard 
Published: September 2008

AbstractTo satisfy the growing demand for mobile communications micro‐cellular systems are expected to be introduced in the near future. For these, effective procedures not only for channel allocation but also for load balancing and call admission control still have to be developed. Here, the knowledge of the actual interference relations between radio cells is a key issue for both the more traditional channelized systems and the recently proposed spread spectrum techniques. Realizing that the interference relations among the cells are only slowly varying, the authors generalize the existing local and short term approaches to interference detection by including a memory trace in the evaluation procedure. A compatibility matrix for the cells is learned by statistically correlating carrier and interference power levels with call activities. In this paper, the overall system design is presented along with the detailed description of the learning procedure which is thought of as both an integrated component of future radio network management systems as well as a possible enhancement of already existing radio network planning methods. Simulations show that the adaptive strategy offers a considerable capacity increase that results from an increased spectrum efficiency.
New IIR echo canceller using a dual error criterion and lattice structures
Authors: Gerald Jose A. B. , Esteves Nelson L. , Silva Manuel M. 
Published: September 2008

AbstractAn adaptive IIR echo canceller for data transmission is presented, where the output‐error criterion and the equation‐error criterion are used simultaneously. The combined use of these two error criteria provides a fast initial convergence and leads to unbiased parameter estimates, even in the presence of noise. The poles of the echo path transfer function are modelled by means of lattice structures, which greatly simplifies the stability monitoring. The performance of the proposed echo canceller, as updated by LMS‐type algorithms, is evaluated by computer simulation.
Performance of a traffic smoothing switching element
Authors: Schmidt Kai , Killat Ulrich 
Published: September 2008

AbstractThis paper investigates a switching element which transforms a non‐uniform traffic distribution over the inputs of a switch into a uniform one. The switching element consists of an output buffered matrix switch equipped with non synchronized counters at the input lines for output selection. By means of a combinatorial analysis the desired property of the component is proved. Moreover, it is shown that no losses occur if the number of buffer places equals the number of input lines. Simulation results reveal the excellent performance of the device under various traffic conditions.