Abstract: A system and method for analyzing the real-time performance of a communication device. An aspect of the present invention records information input to the communication device during real-time operation of the communication device. A playback device or module may execute a model of the communication device in a non-real-time environment according to the recorded real-time input information. System execution in the non-real-time playback environment may, therefore, be equivalent to the original operation of the communication device that occurred in real-time. Accordingly, situations that occur in real-time may be efficiently recreated in non-real-time playback. An operator may analyze the past real-time performance of the communication device using the playback device or module, the recorded real-time input information, and a debugger utility if desired, without conducting additional trials to reproduce the desired operational situation.

Abstract: Embodiments of the present invention provide a method, an apparatus, and a system for multiple access. The method includes: receiving, by a network device, a data packet, where the data packet includes identifier information about a terminal; querying, according to the identifier information about the terminal, a correspondence table between identifier information about a terminal and a broadcast channel, and determining a broadcast channel corresponding to the identifier information about the terminal, where the determined broadcast channel is a broadcast channel among a plurality of preset broadcast channels, and the terminal is any terminal in a terminal group corresponding to the determined broadcast channel; and sending, according to the identifier information about the terminal, through the determined broadcast channel, the data packet to the terminal.

Abstract: A method of far-end crosstalk (FEXT) channel estimation in a digital subscriber line (DSL) system, wherein the DSL system comprises a first subscriber line and a second subscriber line, the method comprising allocating a plurality of time slots, wherein the plurality of time slots comprises a first period and a second period, wherein the first period precedes the second period, and wherein each of the first and second periods comprises at least one time slot, transmitting at least one training symbol in the first period onto the second subscriber line in a downstream direction while no transmission is made on the first subscriber line, receiving at least one feedback symbol in the second period from the first subscriber line in an upstream direction, and estimating a level of downstream FEXT from the second subscriber line into the first subscriber line based on the at least one feedback symbol.

Abstract: A digital subscriber line access multiplexer (DSLAM) configured to couple to a first subscriber line and a second subscriber line, wherein the DSLAM comprises at least one transmitter configured to transmit a first signal onto the first subscriber line in a first time slot, transmit a second signal onto the second subscriber line in the first time slot, wherein the first and second signals are linearly related and are intended for a first customer premise equipment (CPE), transmit a third signal onto the second subscriber line in a second time slot, and transmit a fourth signal onto the first subscriber line in the second time slot, wherein the third and fourth signals are linearly related and are intended for a second CPE.

Abstract: A method in a network device for providing end-to-end connection in a unified optical and coax network, comprising receiving at an integrated node device (IND) a frame from an optical line terminal (OLT), wherein the frame comprises a data frame and a logical link identifier (LLID), and placing the data in a one of a plurality of buffers based on the LLID, wherein the one of the plurality of buffers corresponds to a customer premises equipment (CPE) associated with the LLID, wherein the data frame stays intact in a media access control (MAC) layer.

Abstract: Starting up and synchronizing multiple access points in a wireline communications circuit using transceivers compatible with a wireless communications protocol with an adaptive Time Division Multiple Access scheme for a multi-channel medium with colocated transceivers. Synchronization readiness is asserted and the access points wait for a synchronization start signal's assertion. Methods of operating an access point, its implementation as a chip are further disclosed. An access point assembly including the access points and a synchronization circuit are also disclosed.

Abstract: Provided is a system and method for a modem including one or more processing paths. Also included is a number of interconnected modules sequentially arrayed along the one or more paths. Each module is configured to (i) process signals passed along the paths in accordance with the sequence and (ii) implement predetermined functions to perform the processing. Further, each of the modules has a particular degree of functional programmability and the degrees of functional programmability monotonically vary in accordance with the sequence.

Abstract: In a data communication system, a transmitter of a modem, for example, uses a single scrambler to operate in a data communication mode and in a non-data mode. During the data communication mode the scrambler is used to scramble data for communication by the transmitter. During the non-data mode, the scrambler is used to generate a non-data mode signal for communication by the scrambler. The modem may be an ADSL modem, for example, in which case the data communication mode is SHOWTIME while the non-data mode may be Q-mode.

Abstract: An impairment compensation sequence for use in a communication system susceptible to one or more potential impairments each periodic in an integer number of symbols includes N phases, wherein N is selected such that each potential impairment, if present, is periodic therein, and a sequence of symbols, the sequence organized to place at least one instance of each symbol from a predetermined set of symbols in each phase to allow detection of the potential impairments in each of the N phases. The potential impairments may include robbed-bit signaling and padding. Using estimates prepared based on such an impairment compensation sequence, individual phase intervals may be grouped according to similarity of apparent aggregate effect of the impairments thereon without identification of individual impairments active in the particular phases. Constellation points may then be assigned based on group characteristics corresponding to phase intervals.

Abstract: A Finite Impulse Response (FIR) filter is implemented in software on a general purpose processor in a manner which reduces the number of memory accesses as compared to conventional methods. In particular, an efficient implementation for a general purpose processor having a substantial number of registers includes inner and outer loop code which together make K ? [ ( L 1 + L 2 L 1 ? L 2 ) ? N + L 2 L 1 + 1 ] memory accesses and KN multiply-accumulates, where L1 is the number of output vector elements computed during each pass through the outer loop and where L2 is the number of taps per output vector element computed during each pass through the inner loop. The efficient implementation exploits L1+2L2 general purpose registers.

Abstract: In a data communication system, a transmitter of a modem, for example, uses a single scrambler to operate in a data communication mode and in a non-data mode. During the data communication mode the scrambler is used to scramble data for communication by the transmitter. During the non-data mode, the scrambler is used to generate a non-data mode signal for communication by the scrambler. The modem may be an ADSL modem, for example, in which case the data communication mode is SHOWTIME while the non-data mode may be Q-mode.

Abstract: An impairment compensation sequence for use in a communications system susceptible to one or more potential impairments each periodic in an integer number of symbols includes N phases, wherein N is selected such that each potential impairment, if present, is periodic therein, and a sequence of symbols, the sequence organized to place at least one instance of each symbol from a predetermined set of symbols in each phase to allow detection of the potential impairments in each of the N phases. The potential impairments may include robbed-bit signaling and padding. Using estimates prepared based on such an impairment compensation sequence, individual phase intervals may be grouped according to similarity of apparent aggregate effect of the impairments thereon without identification of individual impairments active in the particular phases. Constellation points may then be assigned based on group characteristics corresponding to phase intervals.

Abstract: A method for forming a non-iterative time-domain equalizer (TEQ) and apparatus corresponding thereto. A channel response H(z) is followed by a TEQ response A(z) and a residual output B(z) is chosen so that its degree is less than a cyclic prefix. An error signal is formed so that E(z)=H(z)A(z)?B(z). With a unit input, the error signal is set to zero and B(z)=H(z)A(z). Each signal is expressed as a polynomial, having varying degrees, and a having corresponding coefficients. Once expanded, the coefficients of similar degree can be equated on both sides of the equation. The error signal can then be determined in terms of coefficients corresponding to the TEQ and the residual signal. The coefficients of the channel response can be derived from the channel training estimates. The error signal is minimized and the result is solved for in terms of the desired TEQ coefficients.

Abstract: An impairment compensation sequence for use in a communications system susceptible to one or more potential impairments each periodic in an integer number of symbols includes N phases, wherein N is selected such that each potential impairment, if present, is periodic therein, and a sequence of symbols, the sequence organized to place at least one instance of each symbol from a predetermined set of symbols in each phase to allow detection of the potential impairments in each of the N phases. The potential impairments may include robbed-bit signaling and padding. Using estimates prepared based on such an impairment compensation sequence, individual phase intervals may be grouped according to similarity of apparent aggregate effect of the impairments thereon without identification of individual impairments active in the particular phases. Constellation points may then be assigned based on group characteristics corresponding to phase intervals.

Abstract: Provided is a system and method for a modem including one or more processing paths. Also included is a number of interconnected modules sequentially arrayed along the one or more paths. Each module is configured to (i) process signals passed along the paths in accordance with the sequence and (ii) implement predetermined functions to perform the processing. Further, each of the modules has a particular degree of functional programmability and the degrees of functional programmability monotonically vary in accordance with the sequence.

Abstract: A technique is described for reliably determining whether a direct digital connection exists between a transmitting server modem and a receiving client modem. Such a determination is an essential part of the training procedure for modems that conform to ITU-T Recommendation V.90 but is also applicable to other data communications configurations and equipment. In some configurations in accordance with the present invention, segments of a modem training signal, L1L2, are used to make the determination.

Abstract: Reliable detection of a call-waiting tone is provided by employing a correlation based technique. A modem or other device employing such a technique need not rely on carrier drop detection and is generally insensitive to other energy or noise on the line.

Abstract: In a data communication system, a transmitter of a modem, for example, uses a single scrambler to operate in a data communication mode and in a non-data mode. During the data communication mode the scrambler is used to scramble data for communication by the transmitter. During the non-data mode, the scrambler is used to generate a non-data mode signal for communication by the scrambler. The modem may be an ADSL modem, for example, in which case the data communication mode is SHOWTIME while the non-data mode may be Q-mode.

Abstract: A method for forming a non-iterative time-domain equalizer (TEQ) and apparatus corresponding thereto. A channel response H(z) is followed by a TEQ response A(z) and a residual output B(z) is chosen so that its degree is less than a cyclic prefix. An error signal is formed so that E(z)=H(z)A(z)?B(z). With a unit input, the error signal is set to zero and B(z)=H(z)A(z). Each signal is expressed as a polynomial, having varying degrees, and a having corresponding coefficients. Once expanded, the coefficients of similar degree can be equated on both sides of the equation. The error signal can then be determined in terms of coefficients corresponding to the TEQ and the residual signal. The coefficients of the channel response can be derived from the channel training estimates. The error signal is minimized and the result is solved for in terms of the desired TEQ coefficients.

Abstract: A method for forming a non-iterative time-domain equalizer (TEQ) and apparatus corresponding thereto. A channel response H(z) is followed by a TEQ response A(z) and a residual output B(z) is chosen so that its degree is less than a cyclic prefix. An error signal is formed so that E(z)=H(z)A(z)?B(z). With a unit input, the error signal is set to zero and B(z)=H(z)A(z). Each signal is expressed as a polynomial, having varying degrees, and a having corresponding coefficients. Once expanded, the coefficients of similar degree can be equated on both sides of the equation. The error signal can then be determined in terms of coefficients corresponding to the TEQ and the residual signal. The coefficients of the channel response can be derived from the channel training estimates. The error signal is minimized and the result is solved for in terms of the desired TEQ coefficients.