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Showing papers on "Communication channel published in 1991"


Journal ArticleDOI
TL;DR: A criterion for determining the appropriate drainage density at which to extract networks from digital elevation data is suggested to extract the highest resolution (highest drainage density) network that satisfies scaling laws that have traditionally been found to hold for channel networks.
Abstract: Channel networks with artibtrary drainage density or resolution can be extracted from digital elevation data. However, for digital elevation data derived networks to be useful they have to be extracted at the correct length scale or drainage density. Here we suggest a criterion for determining the appropriate drainage density at which to extract networks from digital elevation data. The criterion is basically to extract the highest resolution (highest drainage density) network that satisfies scaling laws that have traditionally been found to hold for channel networks. Procedures that use this criterion are presented and tested on 21 digital elevation data sets well distributed throughout the U.S.

1,110 citations


Journal ArticleDOI
TL;DR: An analog model of the land mobile satellite channel which can readily be used for software and hardware fading simulation is developed and the most important parameter of this model is the time-share of shadowing.
Abstract: The communication channel between the MARECS satellite at 26 degrees W and a cruising van was measured and recorded in European areas exhibiting satellite elevations from 13 to 43 degrees . Different environments and mobile antennas were tested. The results of an extensive statistical evaluation include spectra of the fading amplitude; probability density, and distribution of the received signal power; and the percentage of time for fade and nonfade periods. Based on the physical phenomena of multipath fading and signal shadowing, an analog model of the land mobile satellite channel which can readily be used for software and hardware fading simulation is developed. The most important parameter of this model is the time-share of shadowing. The Rice factor which characterizes the channel during unshadowed periods, can vary from 3.9 to 18.1 dB. Block error probability density, error gap distribution, and block error probability are discussed. >

791 citations


Journal ArticleDOI
TL;DR: In this paper, the authors seek to extend theory and empirical findings on interfirm influence strategies by examining their use in channel relationships between suppliers and distributors of industrial products, and find that the use of interference strategies in the channel relationship between suppliers, distributors, and industrial products is correlated.
Abstract: The authors seek to extend theory and empirical findings on interfirm influence strategies by examining their use in channel relationships between suppliers and distributors of industrial products....

717 citations


Journal ArticleDOI
TL;DR: A model is presented for the time- and frequency-selective outdoor mobile radio channel based on the physical process of wave propagation in a statistical fluctuating medium and the reduction of this complex scattering problem to a set of relations containing the pertinent statistics for conducting communications system analysis is developed.
Abstract: A model is presented for the time- and frequency-selective outdoor mobile radio channel. which is based on the physical process of wave propagation in a statistical fluctuating medium. The reduction of this complex scattering problem to a set of relations containing the pertinent statistics for conducting communications system analysis is developed. Characteristics of the propagation process, e.g., delay power spectra, amplitude distribution (Nakagami-m-distribution), and correlation functions, are derived in parameterized form from physical considerations. The method allows a classification of real configurations (environments) into several classes and the extraction of the relevant parameters in direct comparison with measured data. The method is applied to typical channel situations in Switzerland. The mathematical modeling of the classes is demonstrated. >

507 citations


Journal ArticleDOI
TL;DR: It is shown that the multistage detectors are capable of achieving considerable improvements over the linear detectors, particularly in near-far situations, i.e., in the demodulation of weak signals in the presence of strong interfering signals.
Abstract: Communication networks using code division multiple access (CDMA) include applications where several packets of information are transmitted synchronously and simultaneously over a common channel. Consideration is given to the problem of simultaneously demodulating every packet from such a transmission. A nonlinear detection scheme based on a linear complexity multistage multiple-access interference rejection algorithm is studied. A class of linear detectors is considered as constituting the first stage for the multistage detector. A bit-error probability comparison of the linear and multistage detectors is undertaken. It is shown that the multistage detectors are capable of achieving considerable improvements over the linear detectors, particularly in near-far situations, i.e., in the demodulation of weak signals in the presence of strong interfering signals. This problem has been of primary concern for currently operational CDMA systems. >

488 citations


Journal ArticleDOI
TL;DR: The influence of several variables on PRMA efficiency, defined as the number of conversations per channel, is examined and it is found that with 32-kb/s speech coding and 720- kb/s transmission (22.5 channels), PRMA supports up to 37 simultaneous conversations, or 1.64 conservations per channel.
Abstract: Packet-reservation multiple access (PRMA) is viewed as a merger of slotted ALOHA and time-division multiple access (TDMA). Dispersed terminals transmit packets of speech information to a central base station. When its speech activity detector indicates the beginning of a talkspurt, a terminal contends with other terminals for access to an available time slot. After the base station detects the first packet in the talkspurt, the terminal reserves future time slots for transmission of subsequent speech packets. The influence of several variables on PRMA efficiency, defined as the number of conversations per channel, is examined. The number of channels is the ratio of transmission rate to speech coding rate. It is found that with 32-kb/s speech coding and 720-kb/s transmission (22.5 channels), PRMA supports up to 37 simultaneous conversations, or 1.64 conservations per channel. The number of conversations per channel is at least 1.5 over a wide range of packet sizes (8 ms of speech per packet to 34 ms) and for all systems with 16 or more channels (transmission rate >or=512 kb/s, with 32-kb/s speech coding). Other factors studied are the sensitivity of the speech activity detector, the retransmission probability of the contention scheme, and the maximum time delay for the transmission of speech packets. >

433 citations


Journal ArticleDOI
TL;DR: Granovetter's threshold model of collective action as mentioned in this paper shows how each new participant triggers others until the chain reaction reaches a gap in the distribution of thresholds, and thus outcomes depend on the network of social ties that channel the chain reactions.
Abstract: Granovetter's threshold model of collective action shows how each new participant triggers others until the chain reaction reaches a gap in the distribution of thresholds. Hence outcomes depend on the network of social ties that channel the chain reactions. However, structural analysis is encumbered by the assumption that thresholds derive from changing marginal returns on investments in public goods. A learning-theoretic specification imposes less stringent assumptions about the rationality of the actors and is much better suited to a structural analysis. Computer simulations suggest that threshold effects may be the key to solving the coordination problem: When individual choices are contingent on participation by others, this interdependence facilitates the coordination of contributions needed to shift the bistable system from a noncooperative equilibrium to a cooperative one. Further simulations with low-density networks show that these chain reactions require bridges that link socially distant actors, supporting Granovetter's case for the strength of weak ties.

430 citations


Patent
03 Apr 1991
TL;DR: In this article, the authors proposed a method for control multiple concurrent calls where each call comprises one or more channels, and the plurality of channels of the single, merged call corresponds to a combination of channels from the first and second calls and may include a signalling channel, a voice channel, and one data channel for each data channel of the first or second calls.
Abstract: A method for use in a multimedia conferencing arrangement to control multiple concurrent calls where each call comprises one or more channels. A first call among a first set of user stations and a second call among a second set of user stations are merged into a single call comprising a plurality of channels among at least three user stations from the first and second sets. The plurality of channels of the single, merged call corresponds to a combination of channels of the first and second calls and may include a signalling channel, a voice channel, and one data channel for each data channel of the first and second calls. The method is also applicable to calls including image or video channels.

422 citations


Patent
26 Mar 1991
TL;DR: In this paper, an endoscope with a plurality of potential channels is described, where the tube is expanded by placing a tapered rod or fluid under pressure along the length of the insertion tube, or by elevating a flat coil into a cylindrical coil.
Abstract: An apparatus and method for providing an endoscope with a plurality of potential channels is disclosed. A tubing (54) having a radially flexible wall is positioned adjacent the endoscope insertion tube (34). The tubing (54) is collapsed prior to inserting the insertion tube (34) into the patient's body. After the insertion tube (34) is within the patient's body, the tubing (54) is expanded to create a channel. A medical apparatus may pass through the channel for performing a medical procedure. The tubing (54) is expanded by placing a tapered rod therethrough, by placing a fluid under pressure within the tubing (54), or by elevating a flat coiled wire into a cylindrical coil. A radially rigid tubing is placed within the expanded flexible tubing (54) to permit medical devices to extend from a position outside of the patient's body to the distal end of the insertion tube (34). A plurality of tubings (54) are provided circumferentially spaced from each other around the insertion tube (34) to permit a combination of medical devices to be used in cooperation with each other to perform a medical procedure. A stiffening member, such as a rod or fluid under pressure may extend partially along the length of the insertion tube (34) to vary the flexibility characteristics of the insertion tube (34) while it is within the patient's body.

421 citations


Patent
10 Sep 1991
TL;DR: In this article, a multiple media system consisting of a central site and a remote site for customizing video and audio presentations comprising a communications channel, a studio processor, a scheduling processor, network processor, transmitters, a transmitter, a video processor, and optionally a matrix switch, a cue processor, matrix-switch processor and a system monitor.
Abstract: A multiple media system having a central site and a remote site for customizing video and audio presentations comprising a communications channel, a studio processor, a scheduling processor, a network processor, a transmitter, a communications processor, a video processor, and optionally a matrix switch, a cue processor, a matrix-switch processor and a system monitor. The studio processor generates one or more content data signals. The content data signals maybe analog or digital, and include text signals, phototext signals and/or audio signals. The scheduling processor generates a schedule data signal, which includes a unique identifier, accounting, administrative and scheduling data. The network processor generates a communication signal which includes the one or more content data signals and the schedule data signals formatted with the video signal. The transmitter transmits the communications signal over the communications channel. At the remote site the communications processor receives the communications signal and selects a first content data signal from the one or more content data signals. The video processor mixes the first content data signal with the video signal. The cue processor is coupled to network feed channel through a matrix switch. In response to detecting network-cue signals, the cue processor generates insertion signals. In response to the insertion-cue signals, the matrix processor controls the matrix switch routes the multiple media signal, which includes the video signal with the additional information from the content data signal, to a network communications channel.

347 citations


Journal ArticleDOI
TL;DR: It is shown, via asymptotics and a range of specific examples, that it is possible to assign a notionaleffective bandwidth to each source, dependent not only on its mean bandwidth but also on its burstiness and on the channel.
Abstract: The Uniform Arrival and Service (UAS) model is one of several appropriate to modelling traffic offered to a multi-service communication channel. We exhibit, via asymptotics and a range of specific examples, that it is possible to assign a notionaleffective bandwidth to each source, dependent not only on its mean bandwidth but also on its burstiness and on the channel. The effective bandwidth can be calculated quickly and efficiently using the results of Anick, Mitra and Sondhi and reduces the multi-service network to the more familar, and well understood, form of a traditional circuit-switched network.

Journal ArticleDOI
D. Kunz1
TL;DR: The results obtained so far indicate that the neural network algorithm can be used to obtain an optimum solution to the channel assignment problem, and was applied successfully for inhomogeneous interference conditions and channel demand.
Abstract: The channel assignment problem, i.e. the task of assigning channels to radio cells in a spectrum-efficient way, is solved by a neural network algorithm. This algorithm is inherently parallel and does not rely on a particular structure of the interference graph. The results obtained so far indicate that the algorithm can be used to obtain an optimum solution. It was applied successfully for inhomogeneous interference conditions and channel demand. Cochannel and cosite constraints were taken into account, and the extension to any other technical restrictions will be possible in an obvious way. The examples studied to date are of a relatively small size; the question remains of how the algorithm behaves when applied to larger and more complex examples. The disadvantages of the algorithm are its long calculation time compared to graph coloring algorithms and the difficulty of finding appropriate parameters. However, the algorithm was not optimized for speed, and the parameter search may be a question of experience. >

Proceedings ArticleDOI
18 Apr 1991
TL;DR: In this paper, the feasibility of bounding the delay jitter for real-time channels in a packet-switched store-and-forward wide-area network with general topology was made.
Abstract: A study is made of the feasibility of bounding the delay jitter for real-time channels in a packet-switched store-and-forward wide-area network with general topology, extending the scheme proposed in previous papers. The authors prove the correctness of the solution, and study its effectiveness by means of simulations. The results show that the scheme is capable of providing a significant reduction in delay jitter, that there is no accumulation of jitter along the path of a channel, and that jitter control reduces the buffer space required in the network significantly. >

Journal ArticleDOI
J.-J. Werner1
TL;DR: A tutorial on the physical environment in which high bit rate digital subscriber line (HDSL) transceivers will have to evolve and succeed is presented, with special attention given to the most damaging impairments that are encountered in subscriber lines.
Abstract: The author presents a tutorial on the physical environment in which high bit rate digital subscriber line (HDSL) transceivers will have to evolve and succeed. Special attention is given to the most damaging impairments that are encountered in subscriber lines, such as propagation loss, linear distortion, crosstalk, bridged taps, and impulse noise. Somewhat less important impairments, such as change of gauge, temperature variation, and thermal noise, are also briefly described. The author concludes with a discussion of the capacity of a twisted-pair channel in a crosstalk-dominated environment. >

Journal ArticleDOI
01 Aug 1991
TL;DR: In this article, a least sum of squared errors (LSSE) channel estimation algorithm is presented for estimating a channel impulse response from a known training sequence, and the effect of channel estimation errors on the performance of some data detectors is also investigated.
Abstract: A least sum of squared errors (LSSE) channel estimation algorithm is presented for estimating a channel impulse response from a known training sequence. Optimum training sequences are found and tabulated for different channel responses and training sequence lengths. The effect of channel estimation errors on the performance of some data detectors is also investigated. A simple approximation for the expected degradation in performance with channel estimation errors is derived.

Patent
24 Oct 1991
TL;DR: The call set-up technique of as discussed by the authors is characterized by the use of channel information from both base station and subscriber terminal in determining the radio traffic channel upon which to set up a new call.
Abstract: The call set-up technique of this invention is characterized by the use of channel information from both base station and subscriber terminal in determining the radio traffic channel upon which to set-up a new call. Communication between the base station and subscriber terminal is carried out on a signalling channel until the traffic channel is chosen. Calls are set-up so that they proceed on the radio channel which, of a set of channels under consideration by the subscriber terminal, contains the least amount of interference as measured at the subscriber terminal. The set of channels under consideration by the subscriber terminal is a subset of the entire set of channels allocated to the service. This subset is comprised of those channels having little interference, as measured by the base station, and which, additionally, are not reserved exclusively for stationary, fixed-allocation services in the geographic location of the base station. The call set-up technique thereby assures that calls proceed on channels containing little interference from the viewpoint of both base station and subscriber terminal. The technique also facilitates sharing of the radio spectrum with stationary, fixed-allocation services because there is no need to program each subscriber terminal to avoid the spectrum allocated to the fixed service.

Journal ArticleDOI
TL;DR: The manner in which neural networks can be utilized as adaptive channel equalizers is described, and simulation results which suggest that the neural network equalizers offer a performance which exceeds that of the linear structures, particularly in the high-noise environment are presented.
Abstract: The problem of reconstructing digital signals which have been passed through a dispersive channel and corrupted with additive noise is discussed. The problems encountered by linear equalizers under adverse conditions on the signal-to-noise ratio and channel phase are described. By considering the equalization problem as a geometric classification problem the authors demonstrate how these difficulties can be overcome by utilizing nonlinear classifiers as channel equalizers. The manner in which neural networks can be utilized as adaptive channel equalizers is described, and simulation results which suggest that the neural network equalizers offer a performance which exceeds that of the linear structures, particularly in the high-noise environment, are presented. >

Patent
Frank Charles Gwyn Owen1
15 Jul 1991
TL;DR: In this article, a method of operating a communications system, particularly a FDM-TDD cordless telephony system, in which, in order to expedite handover, a portable secondary station builds up a record of the status and quality of the other FDM channels in the system by every 1 in n (where n is an integer greater than one) TDD frames monitoring another FDM channel.
Abstract: A method of operating a communications system, particularly a FDM-TDD cordless telephony system, in which, in order to expedite handover, a portable secondary station builds up a record of the status and quality of the other FDM channels in the system by every 1 in n (where n is an integer greater than one) TDD frames monitoring another FDM channel. The value of n is adaptive in that, as the quality of its existing channel deteriorates, the value of n decreases, thereby updating its record more rapidly. At handover, the secondary station is able to choose immediately an acceptable alternative channel, thereby avoiding the time overhead of scanning all the other FDM channels.

Patent
Meidan Reuven1
26 Dec 1991
TL;DR: In this article, a method and apparatus is provided for dynamic distribution of a communication channel load of sectorized-antennae or omni-directional antennae of cell sites in a cellular radio communication system.
Abstract: A method and apparatus is provided for dynamic distribution of a communication channel load of sectorized-antennae or omni-directional antennae of cell sites in a cellular radio communication system. The channel load is distributed by narrowing an antenna (102) beamwidth of an overloaded sector of a cell site (100) and widening an antenna (104) beamwidth of an adjacent sector of the cell site (100). In an alternative embodiment, the channel load is distributed by reducing power of an antenna (124) of a cell site (120) which is adjacent to an overloaded cell site (100). Alternatively, the channel load is distributed by increasing power of an antenna (118) of a cell site (116) which is adjacent to an overloaded cell site (100). Subsequent to the channel load distribution, each of the subscriber units in the overloaded (100) and adjacent cell sites (116, 120) are handed off to the particular cell site which is best able to service the subscriber units.

Proceedings ArticleDOI
20 May 1991
TL;DR: A scheme is developed for providing predictable interprocess communication in real-time systems with (partially connected) point-to-point interconnection networks, which provides guarantees on the maximum delivery time for messages.
Abstract: A scheme is developed for providing predictable interprocess communication in real-time systems with (partially connected) point-to-point interconnection networks, which provides guarantees on the maximum delivery time for messages. This scheme is based on the concept of a real-time channel, a unidirectional connection between source and destination. A real-time channel has parameters which describe the performance requirements of the source-destination communication, e.g., from a sensor station to a control site. Methods to compute guarantees for the delivery time of messages belonging to real-time channels are examined. Problems associated with allocating buffers for these messages are addressed, and a scheme which preserves delivery time guarantees is developed. >


Journal ArticleDOI
Paul H. Siegel1, Jack K. Wolf
TL;DR: It is shown that the introduction of partial response equalization, sampling detection, and digital signal processing has set the stage for the invention and application of advanced modulation and coding techniques in future storage products.
Abstract: Many of the types of modulation codes designed for use in storage devices using magnetic recording are discussed. The codes are intended to minimize the negative effects of intersymbol interference. The channel model is first presented. The peak detection systems used in most commercial disk drives are described, as are the run length-limited (d,k) codes they use. Recently introduced recording channel technology based on sampling detection-partial-response (or PRML) is then considered. Several examples are given to illustrate that the introduction of partial response equalization, sampling detection, and digital signal processing has set the stage for the invention and application of advanced modulation and coding techniques in future storage products. >

Patent
27 Aug 1991
TL;DR: In this paper, the authors present a full duplex digital transmission, high-capacity digital, facility loop-back test, diagnostics and maintenance system having a digital transmission facility, transmission medium, and at least one microprocessor-based, full-duplex facility loopback diagnostics interface is located at predetermined end-user locations within the system.
Abstract: A full duplex digital transmission, high-capacity digital, facility loop-back test, diagnostics and maintenance system having a digital transmission facility, transmission medium, and at least one microprocessor-based, full duplex facility loop-back diagnostics interface is located at predetermined end-user locations within the system. The system is capable of initiating a facility loop-back test and predetermined diagnostics for a predetermined digital transmission span and customer premises equipment at the location of the network interface for a specified end-user. The facility loop-back diagnostics interface has a performance monitoring mode of operation and a maintenance facility loop-back mode of operation. The diagnostics interface can be activated from a remote location and is compatible with and supports a particular protocol, specifically LAP-B protocol. The diagnostics interface has integral performance monitoring capabilities for nonintrusive multiple diagnostics testing and on-line monitoring of multiple predetermined performance characteristics for associated DS1 communications channels, or a specified DS1 communications channel, and customer premises equipment at the network interface. The microprocessor of the performance monitoring unit for the facility loop-back diagnostics interface is synchronized with an internal clock that is driven by conventional power. There is also a long-life battery for preventing historical performance data from being corrupted during a power loss. When the diagnostics interface is in the performance monitoring mode of operation, historical performance data pertaining to predetermined performance characteristics and criteria can be retrieved by utilizing the extended superframe, or superframe, embedded operations channel.

Journal ArticleDOI
TL;DR: The authors describe algorithms for blind equalization of digital communication channels of the quadrature-amplitude-modulation (QAM) type based on the fourth-order statistical moments of the received data sequence, which is adequate for channels with mild intersymbol interference or when the number of data points available for estimating the channel response is very large.
Abstract: The authors describe algorithms for blind equalization of digital communication channels of the quadrature-amplitude-modulation (QAM) type. These algorithms are based on the fourth-order statistical moments of the received data sequence. The first of the two is a linear least-squares-type algorithm. The second algorithm is of the nonlinear least-squares-type. The algorithms use the fourth-order statistical moments of the symbol sequence to explicitly estimate the channel impulse response. The estimated impulse response is used, in turn, to construct a linear mean-square error equalizer. The performance of this equalizer is not optimal in any sense, but it is adequate for channels with mild intersymbol interference or when the number of data points available for estimating the channel response is very large. >

Journal ArticleDOI
TL;DR: A method of channel identification is proposed that exploits the spectral correlation properties of pulse- and carrier-modulated signals to identify channels in the presence of arbitrary noise and nearly arbitrary interference.
Abstract: A method of channel identification is proposed that exploits the spectral correlation properties of pulse- and carrier-modulated signals to identify channels in the presence of arbitrary noise and nearly arbitrary interference Although a pilot or training signal is required, no replica of the transmitted pilot/training signal is needed at the receiver The price paid for this simplicity and the tolerance to extreme channel corruption from noise or interference is that the method is slow That is, relatively long averaging times are needed for measurement of the spectral correlation of the received signal >

Patent
29 Nov 1991
TL;DR: In this paper, an on-screendisplay control circuit controls the display of character information on the television and has the capability of overlaying the channel number and the channel identification information on video portion of a selected channel displayed on a television for a predetermined period of time.
Abstract: A subscriber terminal includes a receiver for receiving a television signal including video, audio and data information. A channel of the television signal may be selected for display on the television. A memory stores channel identification information such as channel identifiers. The channel identifiers include at least one display character. A processor establishes a relationship between channel identification information and channel numbers associated with channels of the television signal. An on-screendisplay control circuit controls the display of character information on the television and has the capability of overlaying the channel number and the channel identification information on the video portion of a selected channel displayed on the television for a predetermined period of time. Program identification information such as program titles may also be displayed. Alternatively or additionally, the channel identification information may be displayed on a display such as an LED display of a subscriber terminal.

Patent
19 Mar 1991
TL;DR: In this paper, the authors propose a scheme for the transmission of digital data with at least two levels of protection, of the type providing for the distribution of the data to be transmitted in the form of digital elements in the time-frequency space and transmission of symbols each formed by a multiplex of N orthogonal carriers modulated by a set of the digital elements.
Abstract: A device for the transmission of digital data with at least two levels of protection, of the type providing for the distribution of the data to be transmitted in the form of digital elements in the time-frequency space and the transmission of symbols each formed by a multiplex of N orthogonal carriers modulated by a set of the digital elements, and transmitted simultaneously, the device including channel .[.encoding.]. .Iadd.encodes .Iaddend.means comprising at least two types of modulation and/or at least two encoding efficiency levels. This enables to optimize the use of the transmission channel by assigning differentiated transmission techniques to portions of data of a same digital train as a function of the different levels of protection sought, against transmission errors.

Patent
19 Jul 1991
TL;DR: In this paper, a connection specific compression system is selectively implemented in connections having the greatest data redundancy and utilizes modularity in implementing data compression in a layered network communication system, where a data compression facility is interfaced in the layered system and intercepts data at a protocol layer prior to the data being packetized for transmission.
Abstract: A connection specific compression system is selectively implemented in connections having the greatest data redundancy and utilizes modularity in implementing data compression in a layered network communication system. A data compression facility is interfaced in the layered system and intercepts data at a protocol layer prior to the data being packetized for transmission. A system acting as a compression host comprises a data packet switch driver which intercepts application data packets passing over layered network interfaces and routes selected client application data packets to an associated local compression process which has an integral network protocol and which compresses the data stream in accordance with a selected compression algorithm. The compressed data passes through the system network protocol and the packet switch driver subsequently sends the compressed data back into the communications stream through a network driver. The compressed data passes across the network communication channel and is received by a decompression host having peer compression/decompression capabilities. The peer compression process decompresses the received data and sends it, via a second/decompression host resident packet switch driver, as though received from the network, into the decompression host system network protocol for connection with an application running on the second host.

Patent
28 Nov 1991
TL;DR: In this paper, a receiver for pseudorandom noise (PRN) encoded signals consisting of a sampling circuit and multiple channel circuits, with each channel circuit including a carrier and code synchronizing circuit, and multiple digital correlators with dynamically adjustable code delay spacing.
Abstract: A receiver for pseudorandom noise (PRN) encoded signals consisting of a sampling circuit and multiple channel circuits, with each channel circuit including a carrier and code synchronizing circuit and multiple digital correlators with dynamically adjustable code delay spacing. The sampling circuit provides high-rate digital samples of the incoming composite signal to each receiver channel. Within each channel, the synchronizing circuit detects cycle slips in a locally generated carrier reference signal as well as phase drift in a locally generated PRN code signal. The correlators compare the digital samples with a locally generated PRN code to produce early, late, and/or punctual correlation signals which are used to adjust the local PRN code. A non-linear sampling technique may be used to provide increased sensitivity in the presence of continuous wave interfering signals.

Patent
Eugene J. Bruckert1
13 May 1991
TL;DR: In this paper, a method and device comprising of determining relative interference for a reuse channel of a first reuse level (100) in relation to relative interference of a second reuse channel (105) resulting in a reuse level gradient and assigning the subscriber unit (115) to at least one reuse level in response to the reuse level gradients is proposed.
Abstract: In a radio frequency communication system employing channelization, such as a cellular TDMA system, and having a plurality of reuse channel levels, such as multiple frequency reuse patterns, each level having at least one associated reuse channel, a method and device comprising: determining relative interference for a reuse channel of a first reuse level (100) in relation to relative interference for a reuse channel of at least a second reuse level (105) resulting in a reuse level gradient and assigning the subscriber unit (115) to at least one reuse level in response to the reuse level gradient.