Abstract: A rollback support method for transactions a node among nodes in a distributed system, including modifying a disposable cache copy of data as part of transaction, propagating a version state and/or a data state of the modified cache to any of the nodes, verifying non-violation of a transaction semantic and/or a replication policy relating to the transaction, committing the transaction to any nodes if successful, revising a version state of other reliable replicas and disposable cache copies in the system based on the version state of the modified disposable cache copy, the disposable cache copies being members of a membership-based view, and updating a data state of other reliable replicas in the system based on the data state of the modified copy, and aborting the transaction if it fails, including restoring the disposable cache copy based on any reliable replicas and/or disposable cache copies in the system.

Abstract: A digital subscriber line communication system (DCLCS) provides voice and data services to a subscriber premises within a building and to high speed data communication devices in the subscriber premises using in-building wiring and to-building wiring without having high speed communication equipment inside the subscriber premises.

Abstract: Methods and systems are provided in a group communication system for dynamically changing a version of a group communication protocol from a first version to a second version transparently to external sources and destinations. The system accommodates newly joining members that can only support versions of the protocol other than the version currently in use without interruption in service. Similarly, the system can upgrade its operating version of the group communication protocol to improve performance when a member having relatively low capabilities exits the group.

Abstract: A method and system for constructing a single topic-connected overlay network are disclosed. A link contribution array, which stores sets of edges in an order according contribution values, is provided. A highest contribution index indicates a highest element in the link contribution array. The method includes performing, at every iteration, a Greedy Merge (GM) algorithm for selecting an edge from the highest element in the link contribution array, removing the selected edge from the link contribution array, and adding the selected edge to a set of overlay edges. After the selected edge is added to the set of overlay edges, contribution values of other edges are updated. The GM algorithm terminates when all elements in the link contribution array become empty. As an output, the GM algorithm generates a single topic-connected overlay network for all topics. A Greedy Join (GJ) and Greedy Leave (GL) functions are also disclosed.

Abstract: Systems and methods for managing connections among nodes in a communication network are provided. The method comprises determining one or more topics of interest for a first node in the network, selecting a second node in the network that shares at least a first topic of interest with the first node, establishing a connection between the first node and the second node so that the second node covers at least the first topic of interest, and establishing additional connections between the first node and at least a third node in the network that covers at least the first topic of interest, in response to determining that the first node is not covered by a total of K nodes with respect to the first topic of interest. Preferably, the communication network is a publish/subscribe network.

Abstract: A transceiver system and method comprises a transmitter and a receiver. The transmitter includes a synthesis filter bank and an overlapping unit. The synthesis filter bank generates and modulates a set of wavelets. The overlapping unit generates a multicarrier signal carrying the information data and provides it to the communication line. The receiver includes a separating unit having a separating shift register and an analyzing filter bank having an N-points FFT unit and a demodulator coupled thereto. The method includes at the transmitter end providing a sequence of prototype wavelets by using N-points IFFT, modulating the sequence of the prototype wavelets by said information data, overlapping the modulated prototype wavelets to generate a multicarrier signal carrying the information data.

Abstract: Methods and systems are provided in a group communication system for dynamically changing a version of a group communication protocol from a first version to a second version transparently to external sources and destinations. The system accommodates newly joining members that can only support versions of the protocol other than the version currently in use without interruption in service. Similarly, the system can upgrade its operating version of the group communication protocol to improve performance when a member having relatively low capabilities exits the group.

Abstract: A rollback support method for transactions a node among nodes in a distributed system, including modifying a disposable cache copy of data as part of transaction, propagating a version state and/or a data state of the modified cache to any of the nodes, verifying non-violation of a transaction semantic and/or a replication policy relating to the transaction, committing the transaction to any nodes if successful, revising a version state of other reliable replicas and disposable cache copies in the system based on the version state of the modified disposable cache copy, the disposable cache copies being members of a membership-based view, and updating a data state of other reliable replicas in the system based on the data state of the modified copy, and aborting the transaction if it fails, including restoring the disposable cache copy based on any reliable replicas and/or disposable cache copies in the system.

Abstract: A computer-implemented method for communication includes receiving over a network multiple ordered sequences of messages. Multiple processing threads are allocated for processing the received messages. Upon receiving each new message from the network, an ordered sequence to which the new message belongs is identified. While there is at least one preceding message in the identified ordered sequence such that processing, using at least a first processing thread, of the at least one preceding message has not yet been completed, processing of the new message is deferred. Upon completion of the processing of the at least one preceding message using at least the first processing thread, a second processing thread is assigned to process the new message, and the new message is processed using the second processing thread.

Abstract: A digital subscriber line communication system (DCLCS) provides voice and data services to a subscriber premises within a building and to high speed data communication devices in the subscriber premises using in-building wiring and to-building wiring without having high speed communication equipment inside the subscriber premises.

Abstract: A method for conveying over telephone lines digitized voice signals simultaneously with digital data signals by means of a communication system, having a transmitter having a discrete multi-tone unit yielding a plurality of carriers of different frequency, several of which are assigned to the voice signals and others to the data signals. The carriers for transmitting voice are selected on the basis of their signal-to-noise ratio characteristics, which carriers can be reallocated dynamically to data transmission. A first tone ordering circuit assigns data streams to data carriers, and a second tone ordering circuit assigns voice streams to voice carriers. Each carrier is modulated by QAM modulation, the data carriers by a sequence of QAM symbols representing data and the voice carriers by a sequence of QAM symbols representing voice. QAM modulation is carried out by a first constellation encoder that modulates the data carriers and a second constellation encoder that modulates the voice carriers.

Abstract: A communication system is provided. It comprises a central office (CO) of a communication service provider and at least one subscriber premise (SP), each SP being linked to a CO by a subscriber-associated communication line comprising a twisted pair of telephone lines, and at least one xDSL modem in the CO coupled to said subscriber-associated communication line. Each SP has a plurality of communication devices, which comprises one or more telephone devices connected to the communication line and at least one network DSL (NDSL) modem associated with a computerized device, the NDSL modem being connected to said communication line; each of said modems having an upstream transmitter and a downstream receiver for communication with the CO and an upstream transmitter and an upstream receiver for communication with other NDSL modems within the SP. Provided is also a novel NDSL modem for use in the above system.

Abstract: A transceiver system and method for transmission of information data over a communication line are described. The transceiver system comprises a transmitter and a receiver. The transmitter includes a synthesis filter bank and an overlapping unit downstream of said synthesis filter bank. The synthesis filter bank is configured for generating a set of wavelets and modulating thereof. The overlapping unit is configured for generating a multicarrier signal carrying the information data and providing thereof to the communication line. The receiver includes a separating unit and an analyzing filter bank downstream of the separating unit. The separating unit includes a separating shift register and a parallel register arranged downstream of said separating shift register. The analyzing filter bank includes an N-points FFT unit and a demodulator coupled to the N-points FFT unit.

Abstract: A method and apparatus for selectively filtering signals on a digital subscriber line (DSL) so as to prevent interference resulting from a telephone instrument switching between its on-hook and off-hook states. One embodiment of the invention utilizes an off-hook detector controlling a variable attenuator element. Another embodiment of the invention uses a switch in parallel with a resistive element to implement the variable attenuator element. Yet another embodiment has an inductive element with a saturable core for providing attenuation to compensate for inconsistencies that result from the changing hookswitch status of a telephone instrument.

Abstract: A communication system includes a plurality of subscribers having a telephone set and different types of home modems coupled using twisted pairs to a local server that includes a plurality of downstream repeaters, a central office coupled to a local server using twisted pair subscriber lines. The central office includes a telephone switch that provides telephone service to the subscribers and a concentrator that connects a plurality of upstream repeaters with a number of office modems that provide data service to the subscriber. A communication system uses CAP or DMT line signals with time division. The line signal transmits with different time framing. Every subscriber line can work in one of three operation modes Asymmetrical mode, Half-Asymmetrical mode, and Symmetrical mode.

Abstract: A communication system is provided. It comprises a central office (CO) of a communication service provider and at least one subscriber premise (SP), each SP being linked to a CO by a subscriber-associated communication line comprising a twisted pair of telephone lines, and at least one xDSL modem in the CO coupled to said subscriber-associated communication line. Each SP has a plurality of communication devices, which comprises one or more telephone devices connected to the communication line and at least one network DSL (NDSL) modem associated with a computerized device, the NDSL modem being connected to said communication line; each of said modems having an upstream transmitter and a downstream receiver for communication with the CO and an upstream transmitter and an upstream recevier for communication with other NDSL modems within the SP.

Abstract: A receiver for high-speed data communications, which receives a differential signal through a pair of signal lines. The receiver includes a common-mode choke, which has first and second signal windings, which are respectively coupled in series to the pair of signal lines so as to attenuate common-mode interference in the differential signal. The choke also has a sampling winding, which is inductively coupled to the signal windings so as to generate a sampled signal responsive to current flowing in the signal windings. Signal processing circuitry is coupled to receive the sampled signal from the sampling winding and to receive the differential signal from the signal windings and to process the differential signal responsive to the sampled signal.

Abstract: A system and method is presented for reducing the power consumed by a line driver driving a signal to be transmitted through a communications media. The preferred method includes the steps of: (1) delaying the signal; (2) determining whether the signal has reached a predetermined threshold value; (3) increasing power supplied to the line driver in response to an indication from the determining step that the threshold has been reached; and (4) delivering the delayed signal to the line driver. The preferred system includes: (1) a digital signal processor; (2) a line driver; (3) a digital delay line disposed between the digital signal processor and the line driver; and (4) a power regulator disposed between the threshold detector and the line driver. The system and method, while applicable to many communications formats, is particularly applicable to communications methods transmitting signals having a relatively large dynamic range, such as xDSL communications techniques.

Abstract: A method for conveying over telephone lines digitized voice signals simultaneously with digital data signals by means of a communication system, having a transmitter having a discrete multi-tone unit yielding a plurality of carriers of different frequency, several of which are assigned to the voice signals and others to the data signals. The carriers for transmitting voice are selected on the basis of their signal-to-noise ratio characteristics, which carriers can be reallocated dynamically to data transmission. A first tone ordering circuit assigns data streams to data carriers, and a second tone ordering circuit assigns voice streams to voice carriers. Each carrier is modulated by QAM modulation, the data carriers by a sequence of QAM symbols representing data and the voice carriers by a sequence of QAM symbols representing voice. QAM modulation is carried out by a first constellation encoder that modulates the data carriers and a second constellation encoder that modulates the voice carriers.

Abstract: A receiver for high-speed data communications, which receives a differential signal through a pair of signal lines. The receiver includes a common-mode choke, which has first and second signal windings, which are respectively coupled in series to the pair of signal lines so as to attenuate common-mode interference in the differential signal. The choke also has a sampling winding, which is inductively coupled to the signal windings so as to generate a sampled signal responsive to current flowing in the signal windings. Signal processing circuitry is coupled to receive the sampled signal from the sampling winding and to receive the differential signal from the signal windings and to process the differential signal responsive to the sampled signal.