Minimum processor instruction for implementing weighted fair queuing and other priority queuing
Granted: May 25, 2010
Patent Number:
7725513
The present invention provides techniques for efficiently determining a minimum or maximum of a plurality of values and the index of the minimum using registers of a processor. The present invention also provides for various processor instructions for determining the minimum/maximum and index of two or more values. The present invention finds particular benefit in implementing heaps and in systems utilizing Weighted Fair Queuing (WFQ).
ATM header compression using hash tables
Granted: May 18, 2010
Patent Number:
7720071
Disclosed are exemplary techniques for compressing ATM cells by substituting reduced headers for the original headers. A header table may be maintained at the transmitting end whereby headers are stored in table entries based on a table index generated from a hash function applied to the headers. A copy of the header table may be maintained at the receiving end and may be updated by populating idle cells with header table contents. Upon receipt of a reduced ATM cell at the receiving end,…
System and method for distributed processing of packet data containing audio information
Granted: April 27, 2010
Patent Number:
7706402
The present invention pertains to a system and corresponding method for distributed processing of packet data containing audio information. The system includes a host processing module for exchanging packet data containing audio information with a data packet network, wherein the host processing module includes host logic for performing non-real-time processing of the packet data. The system also includes a slave processing module coupled to the host processing module for exchanging…
Method and apparatus including a driver for driving a floating bipolar switch
Granted: February 9, 2010
Patent Number:
7659755
A switch for switchably coupling a signal source to a high impedance load. The switch includes a first bipolar transistor and a floating switch driver. The first bipolar transistor is configured to switchably couple the signal source to the high impedance load responsive to a driver signal applied to a base thereof. The floating switch driver has a control input and an output terminal coupled to the base of the first bi-polar transistor to supply the driver signal thereto. The driver…
Downstream power back-off for fiber to node applications
Granted: February 9, 2010
Patent Number:
7660260
There is provided a method of shaping PSD (Power Spectrum Density) of an FTTN (Fiber-To-The-Node) downstream signal from a disturber source to achieve spectral compatibility at an FTTN downstream victim with a downstream PSD from a reference source. The method includes receiving the downstream PSD from the reference source. The method further includes receiving an unshaped downstream PSD from the disturber source. The method further includes shaping the PSD of the FTTN downstream signal…
Technique for improving multiple-channel multi-tone transmissions
Granted: January 26, 2010
Patent Number:
7653138
A technique for improving multiple-channel multi-tone transmissions is disclosed. According to one particular embodiment, a method for transmitting data over at least two bonded channels is provided, wherein each of the at least two bonded channels comprises a plurality of tones. The method may comprise: transmitting a first symbol stream over a first tone in a first bonded channel and over a second tone in a second bonded channel, wherein the first tone is bonded to the second tone, and…
Bit-loading method and system for a DMT transceiver
Granted: January 26, 2010
Patent Number:
7653139
A system and method for a bit-loading algorithm based on an equal error rate principle for each sub-channel (bin) used in a discrete multi-tone modulation (DMT) system. The system and method of the present invention provides a bit-loading algorithm that provides long reach, high data rate and good error performance at a given condition. The bit-loading method and system depends on the Shannon channel capacity formula to allocate bits to different sub-channels. For DMT, the system and…
DBMsOL and FBMsOL power spectral density masks
Granted: December 15, 2009
Patent Number:
7633999
In accordance with one embodiment of the present invention, a power spectral density (PSD) mask for spectral shaping of a dual bit map (DBM) mode downstream transmission is provided. The PSD mask is represented by the equation: PSD DBMsOL = K ADSL_OL × C f 0 × [ sin ? ( ? ? f f 0 ) ] 2 ( ? ? f f 0 ) 2 × 1 1 + ( f f LP3dB ) 12 × 1 1 + ( f HP3dB f ) 6 , 0 ? f ? ? where PSDDBMsOL represents the PSD mask, KADSL—OL…
Double-ended line probing (DELP) for DSL systems
Granted: November 24, 2009
Patent Number:
7623630
Double-ended line probing (DELP) techniques are described herein that enable a loop configuration to be identified based on mathematically simple error functions, which are both time-efficient and less sensitive to measurement errors. A DELP algorithm uses readily available data about the channel that is generated prior to the modem operation (e.g., theoretical loop models) and other available data (e.g., that provided by loop diagnostic modules) to estimate the loop configuration…
Hierarchical trellis coded modulation
Granted: November 3, 2009
Patent Number:
7613985
A system and method for encoding information is disclosed. In one embodiment, information is encoded using a high protection code for the least significant bit and a low protection code for the next three most significant bits. The remaining bits are uncoded. The high protection code may be a turbo code and the low protection code may be a trellis coded modulation code. In this embodiment, the collection of bits is then mapped according to a diagonally shifted QAM constellation…
ISDN crosstalk cancellation in a DSL system
Granted: August 18, 2009
Patent Number:
7577084
To reduce the ISDN crosstalk in an incoming DSL signal, a crosstalk canceller observes at least a portion of the crosstalk signal and reproduces an estimate of the crosstalk signal for at least a portion of that signal within the DSL band. The crosstalk canceller applies a canceling signal based on the estimated crosstalk signal to reduce the crosstalk in the received DSL signal.
Method and apparatus for an interleaver
Granted: August 18, 2009
Patent Number:
7577881
A modem configured to couple to a communication medium for establishing a communication channel thereon. The modem includes an interleaver component configurable as to interleaver parameters ‘I, D’ corresponding to block length and depth respectively. An interleaver memory buffers the communication channel. An interleaver controller controls writing to and reading from the memory of successive data elements of the communication channel with a quantity ‘I’ pairs of write and read…
Return-loss compliant DSL modem line interface unit with complex termination
Granted: August 18, 2009
Patent Number:
7577205
A DSL line interface includes an impedance synthesizer that provides negative feedback to the differential amplifier in the DSL line interface so that the return loss standards for the return signal are met. The DSL line interface unit comprises a differential line driver including a first amplifier and a second amplifier for amplifying the DSL transmit signal, first and second complex termination modules coupled to the outputs of the first and second amplifiers, a transformer including…
Method and apparatus for error correction in multi-line multi-tone gigabit transmission systems
Granted: May 12, 2009
Patent Number:
7532666
A multi-tone modem supporting multi-tone modulation protocols over multiple bundled transmission lines. The multi-tone modem is configured to transmit and receive communication channels each associated with a corresponding one of a plurality of transmission lines. The modem comprises at least one in-channel forward error correction component and a cross-channel forward error correction component. The at least one in-channel forward error correction component discretely encodes and…
Efficient implementation of low power mode in digital subscriber line (DSL) transceivers
Granted: February 3, 2009
Patent Number:
7486608
Efficient implementation techniques of a low power mode, (i.e. L2 mode for ADSL2) for DSL transceivers are described. The techniques save memory space and reduce implementation complexity. A constellation mapper in a DSL transmitter determines the number of bits to be retrieved for an ith sub-carrier in the low power mode based on the number of bits allocated for this same sub-carrier in a normal transmission mode, (e.g. L0 mode in ADSL2) and a bit allocation threshold T. A constellation…
Method and apparatus for extending the frequency range of multi-tone modems
Granted: October 28, 2008
Patent Number:
7443918
An inverse discrete Fourier transform (IDFT) processor processing a lower frequency image of a selected transmit band along with base images of remaining transmit bands called for in a corresponding X-DSL standard. A hybrid upconverter processing the IDFT output by generating a higher frequency replication of the imaged transmit band falling in the standards based frequency range along with the base band images of remaining transmit bands and selectively passing onto the communication…
Method and apparatus for determining codeword interleaver parameters
Granted: August 5, 2008
Patent Number:
7409626
Modem selection of codeword interleaver parameters given standard based, operator based and channel based communication channel performance constraints. A processor implements processes for characterizing the forward error correction codeword and interleaver solution space in terms of expressions from which targeted portions of the solution space may be identified prior to evaluation of the magnitude of the coefficients of the corresponding nodes thereof for compliance with the…
Method and apparatus for extending the frequency range of multi-tone modems
Granted: April 15, 2008
Patent Number:
7359444
An inverse discrete Fourier transform (IDFT) processor processing a lower frequency image of a selected transmit band along with base images of remaining transmit bands called for in a corresponding X-DSL standard. A hybrid upconverter processing the IDFT output by generating a higher frequency replication of the imaged transmit band falling in the standards based frequency range along with the base band images of remaining transmit bands and selectively passing onto the communication…
Method and apparatus for network modems on a shared communications channel
Granted: April 8, 2008
Patent Number:
7356048
A network modem which interfaces, in an embodiment of the invention, with existing wired media within a home. The network modems couple to an existing shared medium and utilize frequency division multiplexing to create a communication network thereon. Communication channels are established, discrete from one another in frequency space with each of the active modems coupled to the shared communications medium. Each communication channel carries simplex communications between two or more…
Method and apparatus for long haul high speed data transmission over XDSL pseudo channels
Granted: August 15, 2006
Patent Number:
7092412
A method and apparatus for extending existing fiber and local area networks across digital subscriber lines, at matching data rates is disclosed. A DSL transceiver system is disclosed with one or more gateways coupled to at least one digital signal processor (DSP). The DSP in turn couples to a plurality of analog-front-ends (AFE's). Each AFE is coupled via associated hybrid front ends (HFE's) to corresponding subscriber lines. The transceiver or a controller coupled thereto maintains a…
