Abstract: A loop around system and method for use in a telephone line monitors line conditions to detect the initiation of loop testing and automatically bypasses an electronic device, such as a DSL line conditioner, used in the line to prevent the electronic device from being inadvertently detected by the testing system as a line fault. The system additionally shuts down power to itself from the line so that it does not interfere with testing, while continuing to monitor the line during testing to detect conditions that characterize the termination of testing, and then automatically switches the electronic device back into the line upon the conclusion of testing. The system and method may be employed unattended at intermediate locations in the line remote from the CO or the CPE.

Abstract: A multi-stage differential amplifier and method provides a gain versus frequency warping response characteristic that equalizes a transmission line of a given length to compensate for frequency-dependent attenuation. The warping response characteristic comprises the inverse of the attenuation versus frequency characteristic of the line, and affords a substantially flat system gain response over a predetermined frequency spectrum. The individual amplifier stages employ operational amplifiers, and are designed using SPICE simulations such that the individual responses of the stages are tailored so they combine to provide the required overall warping response to compensate the line.

Abstract: In a communications system having a modem pool including native modems operating at steady state, a method is provided for modem wake-up at steady-state including measuring modem performance, activating a foreign modem at substantially the foreign modem's maximum data rate and at a power level that is below the foreign modem's normal operational power level, allocating a NEXT cancellation filter as a probe filter, iteratively, until the foreign modem is operating at its normal operational power level, or the modem performance of any of the native modems has degraded subsequent to activating the foreign modem, canceling, using the probe filter, NEXT caused to a native modem by the foreign modem, measuring modem performance, and, if the modem performance of any of the native modems has not degraded, increasing the foreign modem's power level, and, if the modem performance of any of the native modems has degraded, deactivating the foreign modem.

Abstract: A system for transporting a high speed data stream over a plurality of relatively low bandwidth unshielded twisted copper pairs within the local loop plant or in any environment having a plurality of copper lines, such as on campuses, within large buildings, etc. The copper twisted pairs are transformed from a plurality of low bandwidth, low reliability links into a high reliability, very high bandwidth long range communication channel utilizing optimized xDSL transmission technologies over the plurality of copper pairs. A transmit data processor perform scrambling, FEC encoding and interleaving on the data before it is divided and dispatched to the plurality of modem elements for transmission over the local loop plant, either bidirectionally or unidirectionally. On the receiving side, the individual data streams are collected, aggregated and a receive data processor performs de-interleaving, FEC decoding and de-interleaving, resulting in the high speed data stream originally transmitted.

Abstract: In a communications system having a modem pool for communicating via a communications channel, the modem pool including a plurality of modems and having a plurality A of NEXT cancellation filters, a) measuring NEXT impairment caused to at least one target modem among the plurality of modems by at least one disturber modem among the plurality of modems, b) allocating P filters among the A filters as probe filters, where P>=1, c) allocating at least one of the remaining A?P filters among the filters to cancel NEXT from at least one disturber modem among the plurality of modems, and d) measuring, using at least one of the P probe filters, NEXT impairment caused to at least one target modem among the plurality of modems by at least one candidate disturber modem among the plurality of modems to which no A?P filter is currently allocated.

Abstract: In a modem pool system capable of mitigating alien crosstalk, a system including a first modem pool including at least two modems, at least one protected line connected to one of the modems, at least one sensor line connected to another of the modems, at least one alien crosstalk predictor operative to sample an alien signal on the at least one sensor line and provide an alien crosstalk prediction signal, and at least one alien crosstalk prediction summation element operative to receive the alien crosstalk prediction signal from the alien crosstalk predictor and subtract the alien crosstalk prediction signal from a data transmission signal on the protected line.

Abstract: In a system including a first and a second modem pool, each modem pool including a plurality of modems, where each modem in one of the modem pools is paired with a corresponding modem in the other the modem pools, a method for controlling aggregate throughput including initializing each of the modems at an outbound throughput and an inbound throughput, where the outbound and inbound throughputs of at least one of the modems are determined independently from one another, determining an aggregate outbound throughput each of the modem pools, and for each of the modem pools whose aggregate outbound throughput exceeds an associated optimal aggregate throughput, reducing the outbound throughput of any of the modems until the aggregate outbound throughput equals the optimal aggregate throughput.

Abstract: A method for interleaving data frames transmitted via a modem pool, each of the data frames including a plurality of codewords having a predefined level of error correction, including assigning the data frames to corresponding modem timeframes, where codeword symbols in each of the data frames are assigned to time slots in the modems in the corresponding timeframes such that the level of error correction is sufficient to correct error/loss caused to any of the symbols given a predefined level of modem loss/malfunction, and moving any of the codeword symbols assigned to one of the timeframes to another of the timeframes such that the level of error correction is sufficient to correct error/loss caused to any of the symbols given a predefined level of cross-modem error burst while preserving the level of error correction sufficient to correct error/loss caused to any of the symbols given the level of modem loss/malfunction.

Abstract: A method for managing the bandwidth of a modem pool having at least two co-interfering modems, the method including measuring an SNR margin for at least two of the co-interfering modems, and adjusting the bit rate of each of the co-interfering modems such that the SNR margin of each of the co-interfering modems is between a first and a second predetermined threshold.

Abstract: A forward error correction system including a coder operative to encode a data stream into at least one primary code word and at least one secondary code word, where each primary code word is encoded at a first code rate, and each secondary code word is encoded at a second code rate that is greater than the first code rate, at least one transmitting modem for transmitting the code words, at least one receiving modem for receiving the code words, a decoder operative to detect errors in any of the code words, correct any of the errors and erasures in the code words, and communicate the positions of any of the errors, and a controller operative to receive the communication of the error positions, predict from any of the errors in the primary code word at least one error in the secondary code word, and report any of the predicted errors as erasure positions to the decoder.

Abstract: A method of NEXT cancellation in a modem pool having a plurality of modems, where each modem has at least one FIR filter, each FIR filter for filtering signals from a transmitting one of the modems, each modem transmitting a signal having a plurality of contiguous signal blocks, the method including providing a frequency response vector per FIR filter, for each corresponding one of the transmitted signal blocks for each of the modems adapting the length of the signal block to equal the length of the frequency response vector, transforming the adapted signal block into the frequency domain, thereby generating a frequency-domain signal vector, for each of the modems and its at least one FIR filter multiplying the frequency response vector of the FIR filter by a corresponding one of the frequency-domain signal vectors, thereby generating a filtered frequency-domain signal vector, adding the filtered frequency-domain signal vectors, thereby generating a combined filtered frequency-domain signal vector, transformi