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Communications, 1990. ICC '90, Including Supercomm Technical Sessions. SUPERCOMM/ICC '90. Conference Record., IEEE International Conference on

Date 16-19 April 19906

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Displaying Results 1 - 25 of 337
  • IEEE International Conference on Communications ICC '90 Including Supercomm Technical Sessions. SUPERCOMM ICC '90 Conference Record (Cat. No.90CH2829-0)

    Publication Year: 1990
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    Freely Available from IEEE
  • On optimal self-orthogonal quasi-cyclic codes

    Publication Year: 1990 , Page(s): 1256 - 1260 vol.3
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    Some infinite classes of optimal self-orthogonal quasi-cycle (SOQC) equal/unequal error protection codes are presented. These codes are specified by corresponding block designs. Several optimal SOQC codes which were not found by Townsend and Weldon (1967) are also given. From the point of view of implementation, the systematic form of the code has some important advantages. Because of the quasi-cyclic structure, self-orthogonality, and systematic form of the codes, their implementation is very simple.<> View full abstract»

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  • Transport network evolution strategies for ATM based B-ISDN

    Publication Year: 1990 , Page(s): 1469 - 1472 vol.4
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    The capabilities of existing transport networks and of synchronous digital hierarchy systems are discussed. The evolution of these networks toward the target broadband integrated services digital network based on asynchronous transfer mode implies new ATM-based transmission standards. This point is highlighted through the possible introduction strategies. Specifically, the introduction strategy that starts with the CCITT G.702 series and SDH and proceeds toward an optimized ATM transmission network is discussed, and the major advantages and disadvantages of each choice are outlined View full abstract»

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  • Analysis of signal-to-noise ratio distributions and bit error rates for equal gain diversity systems on generalized fading channels

    Publication Year: 1990 , Page(s): 1484 - 1491 vol.4
    Cited by:  Papers (1)
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    An infinite series for the complementary probability distribution function of the signal-to-noise ratio at the output of L-branch equal-gain diversity combiners in Nakagami fading channels is derived. The bit error rate for a matched-filter receiver is analyzed for the combiner and different fading parameters. Both coherent phase-shift keying and differential coherent phase-shift keying are considered. The effects of gain unbalance between branches on the probability distribution of the SNR and on the bit error rates are investigated. Bit-error-rate results are also obtained for coherent and noncoherent reception of frequency-shift keying. The effects of gain unbalances on FSK modulations are also investigated. It is shown that, even with -20 dB (k=0.01) gain unbalance between the branches of a dual combiner, there is still a considerable improvement over the nondiversity instance for the generalized fading model (m=1) View full abstract»

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  • Efficient detection and signal parameter estimation with applications to high dynamic GPS receivers

    Publication Year: 1990 , Page(s): 358 - 364 vol.2
    Cited by:  Papers (2)
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    The author presents a technique for simultaneously detecting data and estimating the parameters of a receiver carrier signal phase that is modulated by unknown data and experiencing very high Doppler, Doppler rate, etc. Such a situation arises, for example, in the case of the Global Positioning System (GPS), where the signal parameters are directly related to the position, velocity, and acceleration of the GPS receiver. The proposed scheme is based upon first estimating the received signal local (data-dependent) parameters over two consecutive bit periods, followed by detecting a possible jump in these parameters. The presence of the detected jump signifies a data transition which is then removed from the received signal. This effectively demodulated signal is then processed to provide the estimates of global (data-independent) parameters of the signal related to the position, velocity, etc. of the receiver View full abstract»

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  • Decision feedback equalization for digital cellular radio

    Publication Year: 1990 , Page(s): 1492 - 1496 vol.4
    Cited by:  Papers (13)  |  Patents (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (436 KB)  

    The authors study an adaptive decision feedback equalizer (DFE) for application in the USA digital cellular radio telephone system. A synchronous DFE and a fractionally spaced DFE are adaptive and use a fast recursive least squares algorithm to track rapid channel variations. Simulation results indicating the performance sensitivity to time delay spread, Doppler shift, and timing jitter are presented. A DFE using a complex fast-Kalman adaptation algorithm is presented, and its bit error rate performance evaluated. The fast Kalman equalizer is found to possess good tracking ability and can track channel variations at vehicle speeds of 50 mph (80 km/h). Sensitivity to sample timing jitter can be reduced by using a DFE with fractionally spaced feedforward taps View full abstract»

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  • Correlation-based fast training of data-driven Nyquist in-band echo cancellers

    Publication Year: 1990 , Page(s): 1280 - 1284 vol.4
    Cited by:  Papers (9)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (532 KB)  

    A novel echo canceller fast training scheme for data-driven `Nyquist' in-band echo cancellers is presented. This scheme simultaneously estimates the near and far echo canceller coefficients by sending a special periodic training sequence and correlating a segment of the sequence with the real echo samples of the sequence. The requirements and the generation of such a training sequence are discussed and described in detail. Fast initialization of a phase-roll compensator is also discussed. The proposed scheme is compared with other echo canceller training schemes View full abstract»

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  • A capacity assignment method with different types of channel capacities for packet switched networks

    Publication Year: 1990 , Page(s): 1210 - 1214 vol.3
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    A novel capacity assignment method for packet switched networks, accepting different types of channel capacities, is proposed. The average packet time delay for each origin destination node pair is taken as a constraint. The method converts a capacity assignment problem into three stages. The first two stages are nonlinear optimization problems and the third is an integralization stage. In the third stage, the concepts of significance evaluation and economy evaluation are introduced, so that the method realizes a more practical and economical network design than conventional methods. Examples are presented which demonstrate that the method is accurate and effective View full abstract»

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  • Next-generation digital access systems

    Publication Year: 1990 , Page(s): 540 - 543 vol.2
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    The trends in electronic access systems and related technologies are reviewed. Such new features as SONET (synchronous optical network) feeder, multiservice line cards, remote testing, and bandwidth management are described. The features described will allow telephone companies to provide present and future services needed by the business community with lower costs, better performance, and faster response than ever before. The use of high-bandwidth optical feeder links extends the performance and capacity benefits of digital fiber systems to the business premises View full abstract»

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  • Fiber to the pedestal . . . then what?

    Publication Year: 1990 , Page(s): 32 - 34 vol.1
    Cited by:  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (268 KB)  

    The possible avenues for evolution of the fiber pedestal are presented. The effects are analyzed on three key components of the fiber-based distribution system: the architecture, the optical network unit, and the subscriber drop. The technical and economic issues regarding the evolution toward various broadband networks are also provided. It is concluded that current analysis favors the placement of a star or logical bus in the distribution plant and the design of a pedestal which is capable of future service evolution. Movement of fiber into the subscriber drop will ultimately hinge on the demand for broadband services View full abstract»

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  • A simple detector for trellis coded PSK mobile radio systems

    Publication Year: 1990 , Page(s): 1497 - 1500 vol.4
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (168 KB)  

    A precoder is added to the regular TC-PSK modulator before convolution coding, and a simple 1-b differential detector is used in the receiver. The decision is made symbol by symbol on the basis of the output samples. The bit error rate of this system is evaluated in fast Rayleigh fading, characterizing mobile radio channels by numerical integration. Results show that the performance of this system is satisfactory for instances of practical interest View full abstract»

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  • Electrical signal processing techniques in long-haul, fiber-optic systems

    Publication Year: 1990 , Page(s): 397 - 403 vol.2
    Cited by:  Patents (26)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (524 KB)  

    Intersymbol interference in long-haul fiber-optic systems can severely degrade performance and consequently limit both the maximum distance and data rate. The sources of intersymbol interference include nonlinearity in the transmit laser, chromatic dispersion in systems operated at wavelengths other than the dispersion minimum of the fiber, polarization dispersion, and bandwidth limitations in the receiver. The authors discuss several techniques for reducing intersymbol interference in single-mode fiber systems with single-frequency lasers and show which techniques are appropriate at high data rates in direct and coherent detection systems. In particular, the performance of linear equalization, nonlinear cancellation, and maximum likelihood detection is analyzed. Computer simulation results for an 8 Gb/s system using measured laser and receiver characteristics showed that in direct detection systems, a 6-tap linear equalizer can reduce the penalty due to chromatic and polarization dispersion by more than 1 dB (or increase the dispersion-limited distance by more than 20%). Nonlinear cancellation and maximum likelihood detection can reduce the penalty even further, more than doubling the dispersion-limited distance in some cases View full abstract»

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  • A fully compatible HDTV system with equi-resolution

    Publication Year: 1990 , Page(s): 876 - 880 vol.3
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    A fully NTSC-compatible, two-channel, wide aspect-ratio HDTV (high-definition television) system with equal vertical and horizontal resolutions is described. The wideband, Y, I and Q components are spectrally split into low-frequency and high-frequency bands. However, only the low-frequency components are spatially split into center and edge segments. The low-frequency edge signals are NTSC encoded and decoded using the existing hardware for the compatible center signals. The system uses augmented vertical filters and produces minimal cross-luminance and cross-chrominance, while providing equal edge and center resolutions View full abstract»

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  • Optical transmitters and receivers for fast optoelectronics

    Publication Year: 1990
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    Summary form only given. The increasing bit rate of optical communication systems and the possibility of developing very fast optoelectronic functional elements have stimulated intensive investigations of the dynamic properties of semiconductor lasers (SLs) and fast photodiodes. The influence of optical feedback on the spectral and noise properties of different kinds of SLs, including distributed-feedback lasers, have been studied both theoretically and experimentally. The dependence of effective microwave modulation frequency range upon optical feedback and the distance between the SL and the external reflector are investigated. Ways of shortening the rise time of different types of photodiodes are also discussed. Experimental investigations of picosecond response time InGaAsP p-i-n photodiodes and GaAs planar Schottky photodiodes have been carried out, and the results presented View full abstract»

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  • Quality design approaches for present and future telecommunication services

    Publication Year: 1990 , Page(s): 1329 - 1333 vol.4
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    Service and network evolution, and the impact on the quality of service are discussed, and a survey of customer views on quality of service is presented in comparison with other public services, such as electricity and railways. Design methods for obtaining desired network performance in such areas as trafficability performances, transmission performance, and network reliability are discussed, along with asynchronous transfer mode network performance in the broadband integrated services digital network View full abstract»

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  • An optimal topology design algorithm for multiple traffic using both dialed up and rented capacities

    Publication Year: 1990 , Page(s): 1215 - 1220 vol.3
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (372 KB)  

    An optimal multitraffic topology design algorithm is presented. It is used to find the optimal topology with respect to a set of input traffic patterns when the operating budget is fixed. The long-haul trunks are assumed to be rented from a carrier in a continuously rented or dialed-up manner. A numerical example is given View full abstract»

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  • Control mechanisms for high speed networks

    Publication Year: 1990 , Page(s): 259 - 263 vol.2
    Cited by:  Papers (5)  |  Patents (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (456 KB)  

    It is pointed out that the high speed of communication links and the altered nature of carried traffic has considerably affected the design and implementation of packet switched networks. The authors explore the effect on the control procedures within the network, specifically focusing on the lessons learned from the prototype PARIS network. The key design philosophy for both the steady-state control and the connection control is described. It is believed that most of the conclusions are general and can be applied to any network, including ATM (asynchronous transfer mode)-based systems View full abstract»

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  • Adaptive CPFSK signaling

    Publication Year: 1990 , Page(s): 626 - 630 vol.2
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (368 KB)  

    An adaptive CPFSK (continuous-phase frequency-shift keying) signaling technique which achieves the maximum constraint length allowed by the number of states of the signals is introduced. Adaptive CPFSK signals select modulation indices dependent on both the transmitted symbol and the state of the system. These signals employ the same set of modulation indices during all signaling intervals. The state transition matrix of the signaling system is used to select the modulation indices. Numerical results obtained for binary full-response and partial-response signaling indicate that adaptive CPFSK signaling performs significantly better than MSK (minimum-shift keying) signaling at almost the same spectral occupancy View full abstract»

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  • Wide range and short time pull-in coherent demodulation method for PSK signal-ACE-DEMO

    Publication Year: 1990 , Page(s): 365 - 369 vol.2
    Cited by:  Papers (2)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (308 KB)  

    A phase-shift keying (PSK) coherent demodulation method known as adaptive carrier estimation demodulator (ACE-DEMO) is proposed. The proposed demodulator consists of four segments, frequency multiplier, adaptive line enhancer (ALE), frequency divider, and multiplier. Analysis and computer simulation show that ACE-DEMO has wide pull-in range and short pull-in time performance compared to conventional phase-locked loop (PLL) demodulators. Low-bit-rate satellite communications systems such as mobile satellite (MSAT) and very small aperture terminal (VSAT), are very suitable applications for ACE-DEMO, since it is very effective for a large carrier offset communications system. In a typical MSAT system, ACE-DEMO's pull-in time is shown to be 10-4 shorter than that of the PLL View full abstract»

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  • SONET enhancements: further integration of transmission and switching

    Publication Year: 1990 , Page(s): 544 - 546 vol.2
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    The creation of the enhanced set of ANSI SONET (synchronous optical network) standards is reviewed. With the completion of Phase II of SONET, it will be possible to integrate many of the signal-transport and operations functions. The new short range optical standard will allow network elements to be interconnected optically on an intraoffice basis. The reissue of T1.102 (Digital Hierarchy-Electrical Interfaces) will contain standards for the electrical interfaces STS-1 and STS-3. The original SONET formats standard (T1.105-1988) will have an addendum attached to fill out the requirements for APS (automatic protection switch) and necessary overhead processing for intraoffice applications. An entirely new standard covering OAM&P (operations, maintenance, administration, and provisioning) is being created. Issues in office level integration are discussed View full abstract»

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  • Redefining what is meant by quality of customer premises equipment

    Publication Year: 1990 , Page(s): 35 - 38 vol.1
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    Traditionally, quality of customer premises equipment (CPE) has meant conformance and reliability, while quality of after sales services has meant lowest downtime period. It is argued here that, although these definitions may be adequate when CPE buyers use their communications facilities as internal technical utilities, they are unsuitable when they use them as business resources to create value for customers. The trends likely to prevail well into the twenty-first century are expected to exert pressure to define CPE quality in terms of conformance to buyers' business strategies and outmode the concept of quality as conformance to technical specifications developed by quality assurance groups. Five main implications of this change for quality managers are identified View full abstract»

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  • A modular bit-serial architecture for large constraint length Viterbi decoding

    Publication Year: 1990 , Page(s): 1501 - 1506 vol.4
    Cited by:  Patents (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (456 KB)  

    A node-parallel Viterbi decoding architecture with bit-serial processing and communication is presented. This structure allows short constraint-length decoders to be expanded, without loss of throughput, to implement a Viterbi decoder of larger constraint length. A variety of generating codes can be accommodated by appropriate wiring of the decoder. Bit-serial communication between processing nodes requires only a single wire; thus on-chip and off-chip wiring requirements are quite small. A constraint-length K=4 `proof of concept' chip was developed using 9860 transistors in 3-μm CMOS. The circuit supports any rate-1/2 or rate-1/3 code with 8-level soft decision. Performance measurements on two rate-1/2 interconnected chips confirm the expected 3.8-dB coding gain at a 10-4 error rate View full abstract»

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  • A multiresolution approach for all-digital HDTV

    Publication Year: 1990 , Page(s): 881 - 885 vol.3
    Cited by:  Papers (5)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (456 KB)  

    The authors investigate the feasibility of a fully digital HDTV (high-definition television) production, processing, coding, and transmission standard that will be a true alternative to analog television. Such a television system is defined as a medium-range technological goal and will have a direct impact on various technologies, including computers, telecommunications, and high-speed VLSI. The authors describe research directions as well as current progress, especially with respect to hierarchical representations and coding methods, nonlinear interpolation techniques, and joint source-channel coding for digital channels. Multiresolution techniques are central to the authors' approach, because they are useful for compression, joint source-channel coding, and compatibility View full abstract»

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  • Design and verification of clock distribution in VLSI

    Publication Year: 1990 , Page(s): 811 - 816 vol.3
    Cited by:  Papers (3)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (560 KB)  

    Some of the design considerations involved in producing a circuit with minimal clock skew are described. The use of the electron beam probe for verifying the effectiveness of the resulting implementation is also described. The electron beam probe allows utilization of the voltage contrast effect for measuring timing relationships between clock signals as they are distributed throughout a VLSI device. An example is shown which demonstrates subnanosecond synchronization of such signals. Another example shows how a combination of marginal design practices and slight processing deviations can lead to significant internal clock skew and device failure. The approach described provides accurate measurement of the timing relationships between internal clock signals without disrupting the physical environment surrounding the probed node or otherwise distorting the edge placement of the signals during the measurement View full abstract»

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  • A highly flexible small digital telephone system

    Publication Year: 1990 , Page(s): 128 - 133 vol.1
    Cited by:  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (480 KB)  

    An architecture and design for a highly flexible, cost-effective, small-business telephone system are described. Targeted at businesses having up to 100 telephones, the system attributes include very simple operation and installation, and a fully digital design, made cost effective through custom silicon integration and a novel architecture. The architecture, based on an intelligent station set software model and functional message broadcast, allows externally connected servers, such as personal computers, to extend the call-processing functionality of the system. The design forms the basis of Northern Telecom's Meridan Norstar key system product View full abstract»

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