Abstract: Through the identification of different packet-types, packets can be handled based on an assigned packet handling identifier. This identifier can, for example, enable forwarding of latency-sensitive packets without delay and allow error-sensitive packets to be stored for possible retransmission. In another embodiment, and optionally in conjunction with retransmission protocols including a packet handling identifier, a memory used for retransmission of packets can be shared with other transceiver functionality such as, coding, decoding, interleaving, deinterleaving, error correction, and the like.

Abstract: Through the identification of different packet-types, packets can be handled based on an assigned packet handling identifier. This identifier can, for example, enable forwarding of latency-sensitive packets without delay and allow error-sensitive packets to be stored for possible retransmission. In another embodiment, and optionally in conjunction with retransmission protocols including a packet handling identifier, a memory used for retransmission of packets can be shared with other transceiver functionality such as, coding, decoding, interleaving, deinterleaving, error correction, and the like.

Abstract: Messages transmitted between a receiver and a transmitter are used to maximize a communication data rate. In particular, a multicarrier modulation system uses messages that are sent from the receiver to the transmitter to exchange one or more sets of optimized communication parameters. The transmitter then stores these communication parameters and when transmitting to that particular receiver, the transmitter utilizes the stored parameters in an effort to maximize the data rate to that receiver. Likewise, when the receiver receives packets from that particular transmitter, the receiver can utilize the stored communication parameters for reception.

Abstract: Through the use of a least squares minimization concept, the loop length, the number of bridged taps and length of the bridged taps on a transmission line can be determined from readily available modem data. In particular, the loop length, the number of bridge taps and the length of bridged taps can be estimated by comparing a measured frequency domain channel impulse response of the transmission line to a model of a loop that is comprised of multiple sections and multiple bridge taps.

Abstract: A transceiver is designed to share memory and processing power amongst a plurality of transmitter and/or receiver latency paths, in a communications transceiver that carries or supports multiple applications. For example, the transmitter and/or receiver latency paths of the transceiver can share an interleaver/deinterleaver memory. This allocation can be done based on the data rate, latency, BER, impulse noise protection requirements of the application, data or information being transported over each latency path, or in general any parameter associated with the communications system.

Abstract: A transceiver is designed to share memory and processing power amongst a plurality of transmitter and/or receiver latency paths, in a communications transceiver that carries or supports multiple applications. For example, the transmitter and/or receiver latency paths of the transceiver can share an interleaver/deinterleaver memory. This allocation can be done based on the data rate, latency, BER, impulse noise protection requirements of the application, data or information being transported over each latency path, or in general any parameter associated with the communications system.

Abstract: A network, such as wired and/or wireless LAN, is configured to have both point-to-point and point-to-multipoint connections. The point-to-multipoint connection(s) is used to communicate information between a plurality of the stations (or modem, or transceivers) in the network, whereas the point-to-point connection(s) are used to communicate information between only 2 stations in the network with the ability to, for example, maximize performance (rate/reach/BER/latency/etc) between those two stations. A master station allocates one or more frequency bands to the various point-to-multipoint and point-to-point connections.

Abstract: An echo cancellation device relies on the known characteristics of the sync frame to monitor, update in an off-line fashion and determine the accuracy of an echo canceller in, for example, a modem, such as an ADSL modem. Specifically, time domain samples are read from the transmit (Tx) and receive (Rx) paths of the modem. These samples are stored in memory. When the sync frame has received a predetermined number of the same Tx samples and Rx samples, the samples are stored. Running averages, over the sync frames, of the TX and RX samples are maintained. These averages are subtracted from a sync frame of samples, to allow LMS updating of the echo canceller taps, free of extraneous signals. Updating, i.e., tracking of changes in the echo channel, is done for the echo canceller in an off-line fashion. The coefficients for the in-line version are updated, while the off-line version is updated over several sync frames. Periodically, the performance of the off-line version is compared with the in-line version.

Abstract: A stable Low Power Mode (LPM) for multicarrier transceivers is described that at least provides transmit power savings while enabling receiver designs that can easily operate without the detrimental effects of fluctuating crosstalk. In one exemplary embodiment, the LPM achieves power savings by reducing the number of used subcarriers without actually performing a power cutback on those subcarriers, thereby allowing a receiver to measure the SNR or noise levels and determine the crosstalk noise on the line regardless of a crosstalking modem being in a LPM or not.

Abstract: Through the use of feedback in determining frequency domain equalization, intersymbol interference can be reduced. Specifically, the determined constellation point closest to the determined received point can be fed back to aid in determining one or more other closest constellation points.

Abstract: Typical forward error correction methods employ Trellis Code Modulation. By substituting low density parity check coding in place of the convolution code as part of a combined modulation and encoding procedure, low density parity check coding and modulation can be performed. The low density parity check codes have no error floor, no cycles, an equal bit error rate for the information bits and the parity bits, and timely construction of both a parity check matrix with variable codeword size and a generator matrix is possible.

Abstract: In a receiver transparent Q-mode, i.e., a Q-mode that is only implemented by a transmitter, the receiver is unaware of the Q-mode state of the transmitter. In this type of Q-mode configuration, the transmitter could enter and exit Q-mode as desired while the receiver, could, for example, continue to function as if operating normally, such as in “showtime.” Through this approach, it is not necessary for the receiver to detect the transmitter's entry and exit of Q-mode.

Abstract: Typical forward error correction methods employ Trellis Code Modulation. By substituting low density parity check coding in place of the convolution code as part of a combined modulation and encoding procedure, low density parity check coding and modulation can be performed. The low density parity check codes have no error floor, no cycles, an equal bit error rate for the information bits and the parity bits, and timely construction of both a parity check matrix with variable codeword size and a generator matrix is possible.

Abstract: The ability to accurately and efficiently calculate and report communication errors is becoming more important than ever in today's communications environment. More specifically calculating and reporting CRC anomalies in a consistent manner across a plurality of communications connections in a network is crucial to accurate error reporting. Through a normalization technique applied to a CRC computation period (e.g., the PERp value), accurate error identification and reporting for each individual connection can be achieved.

Abstract: In a receiver transparent Q-mode, i.e., a Q-mode that is only implemented by a transmitter, the receiver is unaware of the Q-mode state of the transmitter. In this type of Q-mode configuration, the transmitter could enter and exit Q-mode as desired while the receiver, could, for example, continue to function as if operating normally, such as in “showtime.” Through this approach, it is not necessary for the receiver to detect the transmitter's entry and exit of Q-mode.

Abstract: A system and method that scrambles the phase characteristic of a carrier signal are described. The scrambling of the phase characteristic of each carrier signal includes associating a value with each carrier signal and computing a phase shift for each carrier signal based on the value associated with that carrier signal. The value is determined independently of any input bit value carried by that carrier signal. The phase shift computed for each carrier signal is combined with the phase characteristic of that carrier signal so as to substantially scramble the phase characteristic of the carrier signals. Bits of an input signal are modulated onto the carrier signals having the substantially scrambled phase characteristic to produce a transmission signal with a reduced PAR.

Abstract: At a transmitter, an ATM cell stream is received from the ATM layer and is distributed on a cell-by-cell bases across multiple DSL PHY's. At the receiver, the cells from each DSL PHY are re-combined in the appropriate order to recreate the original ATM cell stream, which is then passed to the ATM layer.

Abstract: Using a known or later developed time domain equalizer coefficient training algorithm, a least square solution for the time domain equalizer coefficients is taken at a starting point and iteratively improved on. In particular, the improvement is directed towards maximizing number of bits per frame loaded over the time domain equalizer coefficient choice. This can be accomplished by maximizing capacity directly rather than setting a goal to shorten the channel and hoping that the capacity will be maximized as a result.

Abstract: An alternative approach to coping with the ever increasing demand for faster communications hardware is to design modems that are capable of operating its speeds at a higher data rate than a speed required for a single port of the standard communication rate for that modem. Basically, by utilizing a resource manager, that directs the data in and out of the various portions of the modem in an orderly manner, keeping track of which of the ports is being operated at any given point in time, a standard single port modem can be reconfigured, for example, at an over clocked rate, to manipulate the data input and output of a modem.

Abstract: A three-port TDR front end comprises numerous components. An exemplary three-port TDR front end is a DSL modem. Information-bearing TDR signals are distorted as they pass through these components. With a perfect model of the response of its front-end, a TDR system usually can compensate for the effects of its front-end. In reality, however, the electrical characteristics of each component vary from design-to-design, board-to-board, and slowly over time. The result is imperfect knowledge about the true response of the front-end, errors in the model of the front-end, and degraded TDR performance. At least for this reason it is important to precisely calibrate the response of the TDR front-end through the use of a TDR modeling system.