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Communications, IEEE Transactions on

Issue 11 • Date November 1987

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  • [Front cover and table of contents]

    Publication Year: 1987 , Page(s): 0
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    Freely Available from IEEE
  • [Back cover]

    Publication Year: 1987 , Page(s): 0
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    Freely Available from IEEE
  • Throughput and Packet Delay Analysis for the H-Network: CSMA/CD with Adaptive and Nonadaptive Backoff Protocols

    Publication Year: 1987 , Page(s): 1146 - 1152
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (648 KB)  

    In this work, we present the structure of the H-Network, which is a high data rate (∼ 7 Mbytes/s) local area network used to provide point to point and broadcast communication for the Homogeneous Multiprocessor. We also present the analysis, and obtain the throughput and packet delay characteristics for the H-Network operating under CSMA/CD with adaptive and nonadaptive backoff protocols. View full abstract»

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  • Two Parallel M/G/1 Queues where Arrivals Join the System with the Smaller Buffer Content

    Publication Year: 1987 , Page(s): 1153 - 1158
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (544 KB)  

    We consider two parallel, infinite capacity, M/G/1 queues characterized by ( U_{1}(t), U_{2}(t) ) with U_{j}(t) denoting the unfinished work (buffer content) in queue j . A new arrival is assigned to the queue with the smaller buffer content. We construct formal (as opposed to rigorous) asymptotic approximations to the Joint stationary distribution of the Markov process ( U_{1}(t), U_{2}(t) ), treating separately the asymptotic limits of heavy traffic, light traffic, and large buffer contents. In heavy traffic, the stochastic processes U_{1}(t) + U_{2}(t) and U_{2}(t) - U_{1}(t) become independent, with the distribution of U_{1}(t) + U_{2}(t) identical to the heavy traffic waiting time distribution in the standard M/G/2 queue, and the distribution of U_{2}(t) - U_{1}(t) closely related to the tail of the service time density. In light traffic, we obtain a formal expansion of the stationary distribution in powers of the arrival rate. View full abstract»

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  • Communicating Via Meteor Burst at Short Ranges

    Publication Year: 1987 , Page(s): 1217 - 1221
    Cited by:  Papers (11)
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    This paper examines the relationship between range and performance of meteor burst communication systems. Three performance measures are considered: average duty cycle, average throughput for a system which transmits fixed length message packets at a fixed data rate, and waiting time to deliver a fixed length message. In particular, we examine the range dependence of the three measures at ranges of less than 400 km. It will he demonstrated that communication connectivity can be maintained at short ranges by a combination of efficient protocol and proper antenna pattern designs. View full abstract»

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  • Motion-Compensated Coder

    Publication Year: 1987 , Page(s): 1171 - 1178
    Cited by:  Papers (8)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (784 KB)  

    In an earlier paper, an extension of the pel recursive techniques of Netravali and Robbins [2] and Cafforio and Rocca [3] was introduced. Here a method is provided to realize the algorithm in hardware, with some approximations. The prediction error distribution allows the use of quantized variables to a lookup table of reasonable size. The algorithm is then incorporated into a simple multimode coder capable of 1.5 bits/pel on the sequence examined. The coder incorporates a spot filter, quantizer, block run length coding, and variable word length coding and subsampling. Simulation results are presented, including bit rate, buffer status, and mode control analysis. View full abstract»

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  • The Design of a High-Performance Error-Correcting Coding Scheme for the Canadian Broadcast Telidon System Based on Reed-Solomon Codes

    Publication Year: 1987 , Page(s): 1113 - 1123
    Cited by:  Papers (12)  |  Patents (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1248 KB)  

    Error correction can greatly improve the performance and extend the range of broadcast teletext systems. In this paper, the requirements for an error-correcting scheme for broadcast teletext in North America (NABTS) are set down. An error-correction scheme which meets all these requirements is then described. The simplest case employs the one parity bit in each 8 bit byte and no suffix of parity check bits at the end of each data block. The next level also uses a single byte of parity check bits at the end of each data block. Adding a second byte of parity checks at the end of each data block results in a Reed-Solomon code, called the C code, for each data block. Adding one data block of parity checks after h - 1 data blocks results in a set of h data packets being encoded into a bundle, in which vertical C codes provide powerful interleaving. In a final alternative, two data blocks hold the check bytes for the vertical codewords, and the most powerful coding scheme, the double bundle code, results. The detailed mathematical definitions of the various codes are referred to or described, formulas for performance calculations are referred to, and performance curves are presented for the AWGN channel as well as for measured field data. These performance curves are discussed and compared to the performance of a difference set cyclic code, originally designed for the Japanese teletext system, which corrects any 8 bits in error in a packet. View full abstract»

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  • Optimization of Linearly Equalized QAM

    Publication Year: 1987 , Page(s): 1234 - 1236
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (304 KB)  

    A QAM signal transmitted over a channel with linear distortion and additive white Gaussian noise can be linearly equalized at the receiver to eliminate intersymbol interference. If the QAM signal is power constrained and a given symbol error rate is required, we show that it is possible to maximize the bit rate of this system by optimizing the symbol rate and the number of bits/symbol. Ideal linear equalization is assumed at the receiver to overcome the distortion introduced by the channel. As an example, a Gaussian channel is chosen, and the bit rate is maximized for this channel. The QAM maximization is especially useful for channels with slowly decaying channel attenuation characteristics, e.g., the twisted-pair channel. View full abstract»

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  • Performance Improvement of DPLL's in Non-Gaussian Noise Using Robust Estimators

    Publication Year: 1987 , Page(s): 1207 - 1216
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (992 KB)  

    This paper deals with the analysis of DPLL's operating in the presence of non-Gaussian noise. The loop model developed here allows for multiple input samples each loop sampling period, complex processing of the input sample set, and various noise distributions. In particular, six different robust estimators are used as processors of the input: these are the trimmed mean estimator, a one-step Huber M -type estimator, a new M -type estimator, and three versions of a zero-memory nonlinear (ZNL) estimator: hole punch, limiter, and sign detector. The tracking performance of a second-order DPLL is simulated and analyzed for five different types of noise: Gaussian, contaminated Gaussian, Laplace, Middleton Class A , and generalized exponential. Comparisons are made for signal-to-noise ratios ranging from 0 to - 10 dB. It is found that the ZNL estimators provide performance superior to that of the other robust estimators, especially for noise densities that are heavy tailed. View full abstract»

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  • Performance of DS/SSMA Communications in Impulsive Channels--Part I: Linear Correlation Receivers

    Publication Year: 1987 , Page(s): 1179 - 1188
    Cited by:  Papers (54)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1120 KB)  

    The performance of digital linear correlation receivers is studied in a multiuser environment. There are assumed to be two types of sources interfering with data transmission: multiple-access interference, and additive channel noise which is attributed to impulsive noise sources in the environment. The contribution of multiple-access interference is examined by considering K asynchronous users transmitting simultaneously over a linear channel using the binary PSK direct-sequence spreadspectrum multiple-access (DS/SSMA) technique. Alternatively, the effects of the non-Gaussian impulsive channel in such a system are studied by modeling the samples of noise after front-end filtering. Errorprobability performance under these conditions is compared to that for additive white Gaussian noise (AWGN) channels. Due to computational complexity, exact analysis is limited here to systems utilizing short spreading sequences. Computationally simple methods are proposed for approximating the average error probability when the length of the signature sequences is large. Furthermore, some asymptotic results are obtained for the case of infinitely long sequences. In all cases, performance variation is examined as the shape of the noise density varies with SNR held constant. The results of this analysis indicate that the presence of impulsive noise can cause significant performance degradation over that predicted from an AWGN model, even when the total noise power does not increase. View full abstract»

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  • Distributed Store-and-Forward Deadlock Detection and Resolution Algorithms

    Publication Year: 1987 , Page(s): 1139 - 1145
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (920 KB)  

    Distributed algorithms for the detection and resolution of deadlocks in store-and-forward computer communication networks are presented and validated. The algorithms use a fixed amount of storage at each node (that is independent of the size of the network). The detection algorithm is simple but requires network-wide coordination. The resolution algorithm is based on earlier approaches, but uses the network-wide coordination to address certain synchronization problems. When the detection and resolution algorithms are merged, it is guaranteed that packets will arrive at their destinations in finite time. View full abstract»

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  • On the Application of Importance Sampling to BER Estimation in the Simulation of Digital Communication Systems

    Publication Year: 1987 , Page(s): 1231 - 1233
    Cited by:  Papers (16)
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    Importance sampling (IS) is a useful technique for reducing the number of Monte Carlo trials in BER estimation. Two important aspects of recent research work in this area are to find more applications of IS BER estimation and to seek a good bias scheme in the implementation of the estimator. This correspondence presents a general and rigorous mathematical description of these aspects of this problem which, we hope, will be useful for further research. We also present a general result on how to choose a good bias scheme which may provide some insight into the problem. View full abstract»

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  • Optimal Dynamic Routing in Single Commodity Networks by Iterative Methods

    Publication Year: 1987 , Page(s): 1199 - 1206
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (784 KB)  

    In this paper, we present iterative methods for finding optimal state-dependent routing strategies in single commodity networks. The key to our method is to show that there exists a family of optimization problems with convex cost and linear constraints that have solutions that can be converted into an optimal routing strategy by way of a flow relaxation transformation. These problems, when solved by certain iterative algorithms, lead to different convergence rates. In particular, one of the problems has quadratic cost. To solve one of these optimization problems, we use an iterative projected descent direction algorithm due to Bertsekas. We present an alternative to the Armijo-like step size rule of the algorithm, which we believe is more robust. Also included are Newton-like descent directions that take a reasonable amount of time to compute. Finally, some results of our computer experiments are summarized. View full abstract»

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  • Multipath Diversity Reception of Spread-Spectrum Multiple-Access Communications

    Publication Year: 1987 , Page(s): 1189 - 1198
    Cited by:  Papers (56)  |  Patents (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1064 KB)  

    The analysis of a multipath-combining receiver for directsequence spread-spectrum communications through a specular multipath channel is developed. The analysis applies to systems that use quadriphase-shift-keyed, offset quadriphase-shift-keyed, minimum-shiftkeyed, or binary phase-shift-keyed modulation. The measures of performance are the signal-to-noise ratio and approximations to the error probability involving the signal-to-noise ratio. The performance of a multipath-combining receiver is determined not only for the case of a single transmitter, but also for the case of multiple interfering transmit, ters. Furthermore, the performance of the system is determined in terms of parameters of the signature sequences. These parameters can be used as guides in selecting signature sequences for the system. Results are also given for the case of randomly generated signature sequences. View full abstract»

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  • Response Time in a Teletext System: An Individual User's Perspective

    Publication Year: 1987 , Page(s): 1159 - 1170
    Cited by:  Papers (21)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (920 KB)  

    Teletext is a one-way, broadcast-delivery information system. Pages of information are continuously broadcast to the users. User terminals monitor the broadcast stream and requested pages, once recognized, are captured and stored. Teletext systems possess many attractive features. Among them are simplicity of operation and insensitivity of system performance to user loads. Previous research has considered the issue of response time optimization in teletext systems. In those studies, response time was averaged over the entire user population. In this paper, we analyze an individual user's response time experience. Needless to say, this provides a better gauge of the quality of service being delivered. In addition, this perspective provides the appropriate framework for evaluating strategies that take advantage of user terminal storage capabilities to improve response time performance. To demonstrate this, one such strategy is developed and analyzed. Numerical examples that illustrate the use of the paper's results are also presented. View full abstract»

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  • A Noncoherent Delay-Lock PN Tracking Loop: Impact of RFI and Nonideal Arm-Filter Characteristics

    Publication Year: 1987 , Page(s): 1240 - 1244
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (408 KB)  

    A noncoherent delay-lock PN tracking loop is investigated. The approach used is one in which simulation and analysis are combined to generate tracking performance. Performance data are presented for PN phase jitter standard deviation and compared to theoretical results. The impact of radio frequency interference (RFI) and gain/phase imbalances on PN tracking performance is determined and performance data are given. It is suggested that self-noise terms (introduced via the correlation operation between the incoming signal and local PN code) and nonideal arm-filter characteristics (resulting in gain/phase imbalances) may be significant factors in the investigation of PN tracking performance for those cases in which PN code timing synchronization is a major concern. View full abstract»

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  • Performance of Quadrature Amplitude Modulation for Indoor Radio Communications

    Publication Year: 1987 , Page(s): 1236 - 1238
    Cited by:  Papers (26)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (312 KB)  

    The performance of M -QAM for indoor radio communications is evaluated via a realistic model for indoor multipath propagation [1]. It is found that the outage (BER < 10-4) is about 0.3 percent at 1 Mbit/s and 20 percent at 4 Mbits/s. Two-antenna predetection diversity reduces the outage from 1.2 to 0.04 percent at 2 Mbits/s. Increasing the signaling pulse rolloff factor from 0.5 to 1.0 reduces the outage by not more than 35 percent. View full abstract»

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  • Performance Analysis of Finite Nonhomogeneous Population Tree Conflict Resolution Algorithms Using Constant Size Window Access

    Publication Year: 1987 , Page(s): 1124 - 1138
    Cited by:  Papers (9)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1552 KB)  

    Multiple-access protocols control access to a broadcast communication channel. Tree conflict resolution algorithms are the heart of some distributed multiple-access protocols with nice properties like stability, high capacity, and low delay under light load. We consider a random access protocol based on a tree conflict resolution algorithm similar to one first proposed by Capetanakis, but in which constant size windows on the arrival time axis are used to admit packets into the algorithm instead of the more common "free" or "blocked" access methods. We obtain exact recursive relationships for the (steady-state) distribution of packet delay, and thus, the exact throughput-delay curve for any finite (in general, nonhomogeneous) configuration under a Bernoulli-per-window arrival model. Then, we consider the address assignment problem. We show that by choosing an appropriate addressing scheme, we can improve the performance of the algorithm with respect to both mean delay and maximum throughput. View full abstract»

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  • Optimum Combining for Indoor Radio Systems with Multiple Users

    Publication Year: 1987 , Page(s): 1222 - 1230
    Cited by:  Papers (74)  |  Patents (50)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (944 KB)  

    This paper studies the use of optimum combining to increase the capacity of narrow-band in-building radio communication systems with multiple users. We consider systems consisting of a base Station with numerous remotes in a Rayleigh fading environment and study the problem of more users requiring channels than the number of channels available. A system is described that, with multiple antennas at the base station but only one antenna at each remote, uses optimum combining to suppress interfering signals. We show that this system, with M antennas at the base station, can achieve an M -fold increase in the number of users or tolerate M - 1 interferers from other systems. Thus, with optimum combining, radio communications can be used in high-density, multiple-user environments, such as within buildings, even when only limited bandwidth is available. View full abstract»

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  • On the Relation Between the Finite and the Infinite Population Models for a Class of RAA's

    Publication Year: 1987 , Page(s): 1239 - 1240
    Cited by:  Papers (24)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (272 KB)  

    We examine the relation between the finite and the infinite population models for a class of random access algorithms. The algorithms in the class are a combination of random access and reservation techniques, they are synchronous, and they are studied under the condition that each of the users can monitor the channel feedback continuously (full feedback sensing). For any finite number of independent and identical users in the system, and any i.i.d. arrival process per user, the algorithms are stable, provided that the total input rate is less than one. However, as the population size increases, the stability of an algorithm in the class is determined by its throughput in the presence of the infinite population model for all practical purposes. View full abstract»

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Aims & Scope

IEEE Transactions on Communications focuses on all telecommunications including telephone, telegraphy, facsimile, and point-to-point television by electromagnetic propagation.

 

 

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Editor-in-Chief
Robert Schober
University of British Columbia