Abstract:
A network interface device includes a first interface, a power extractor, a transceiver, and a second interface. The first interface receives a signal that includes both power and packetized information. The power extractor extracts the power from the signal and powers the transceiver. The transceiver extracts the packetized information from the signal and communicates the information to a user device using the second interface.
Abstract:
In a communication system that utilizes DMT technology to couple a primary site (102) to a plurality of secondary sites (104-108), carrier channel allocations may be updated as follows. At periodic intervals, the primary site requests updating bit loading information from the secondary sites. Upon receiving the updated bit loading information, the primary site (102) determines an updated call bit loading table for each active call. From this, the primary site (102) determines whether current carrier channel allocation provides sufficient bandwidth. When the current carrier channel allocation does not provide the sufficient bandwidth, the primary site modifies the current carrier channel allocation to meet the bandwidth requirements.
Abstract:
A method reliably communicates content for multiple subscriber lines via a single physical transmission medium between a telecommunication gateway and equipment at a customer location. In that method, content for two or more subscriber lines of the customer location is received and converted into packetized data for network communications and/or multiplexed to form an added-main-line (AML) signal that includes power. The packetized data or the AML signal is communicated between the customer location and the telecommunication gateway via the single physical transmission medium. External power can be used to extract the content for the two or more subscriber lines from the packetized data in a primary mode of operation, and the power from the AML signal can be used to extract the content for the two or more subscriber lines from the AML signal in a backup mode of operation.
Abstract:
In the present invention, an ADSL system (10) identifies good bin as a bin capable of successfully transmitting data to a destination. A bad bin is identified as a carrier that is not capable of successfully transmitting data to the destination. A marginal bin is identified as a carrier that may be capable of transmitting data to the destination. The power to a bad bin is reduced and allocated to the marginal or good bin(s) to allow an increased bit rate. In another embodiment, the power to marginal bin is reduced and allocated to the good bin(s).
Abstract:
An ADSL receiver (200) receives an upstream modified ADSL signal and an ISDN signal from a remote terminal (32) on a twisted-pair copper wire (18). An ADSL transmitter (100) of the remote terminal (32) transmits the ADSL signal in a frequency range above an ISDN frequency range so that the ADSL signal does not overlap the frequency range of the ISDN signal. In one embodiment, the ADSL receiver (200) includes a band pass filter (201), an analog-to-digital converter (203), a decimator (205), a fast Fourier transform (210), and a digital signal processor (212). The decimator (205) converts the ADSL signal back to base band, thus allowing an ADSL signal source to simultaneously utilize the telephone line with an ISDN signal source, without significantly reducing ADSL throughput.
Abstract:
A simple fast and robust echo canceller for both synchronous and asynchronous multicarrier transceiver systems. A first residual time domain echo component is separated from a receive signal in a first frame and a second residual time domain echo component is separated from a receive signal in the next consecutive frame. The first and second residual time domain echo components from consecutive frames are combined to obtain a combined residual time domain echo component. The combined residual time domain echo component is used to adaptively update coefficients in a transfer function representing an estimate of the echo channel in the multicarrier transceiver system. The separation of the echo components from the receive signal eliminates dependence on the receive signal so that convergence is substantially faster and not signal dependent. Performance of the echo canceller is virtually independent of the receive signal and allows reliable tracking of changes in the echo channel over time.
Abstract:
A transceiver (5) for an asymmetric communication system such as asymmetric digital subscriber line (ADSL) includes a configuration register (71) defining operation at either a central office (CO) or a remote terminal (RT). The configuration register (71) includes a control bit (72) for selecting either CO or RT mode. The transceiver (5) includes a signal processing module (70) configured according to the state of the control bit (72). For example, a digital interface (70) converts transmit data into transmit symbols and converts received symbols into receive data. The digital interface (70) uses a large memory (158) as a buffer in the transmit path and a small memory (160) as a buffer in the receive path in CO mode. In RT mode, the digital interface (70) uses the small memory (160) in the transmit path and the large memory (158) in the receive path. The selective configuration allows a single integrated circuit to be used in both CO and RT equipment.
Abstract:
A method for recovering the clock in an ADSL (asymmetric digital subscriber line) communication system at the receiver to match the frequency of the transmitted signal. A digital phase locked loop (DPLL) based clock is used to adjust the frequency of data read accesses from a FIFO (first-in first-out) memory (26) in a transceiver unit. The frequency is adjusted according to a predetermined offset value, where the offset value indicates the relative difference between a read location in the FIFO memory (26) and a write location. The predetermined offset value defines an operating point or nominal data location in the FIFO memory (26). A FIFO phase detector (31) determines and affects the frequency adjustment to maintain the FIFO memory at approximately the operating point. One embodiment provides clock recovery for a received ADSL subchannel and a means to recover a 16 kHz clock for a channel control.
Abstract:
A flexible asymmetrical digital subscriber line (ADSL) transmitter is able to operate simultaneously with integrated services digital network (ISDN) terminal equipment (TE) using a common telephone line (18). The ADSL transmitter changes the frequency content of a frequency-encoded ADSL signal (104) so that its frequency content does not overlap the frequency content of the ISDN TE signal. A corresponding ADSL receiver located within a central office (CO) adapts to the changed frequency content, allowing the ADSL signal to be transmitted over the telephone line without substantial loss of signal integrity. In one embodiment, an ADSL transmitter (100) converts ADSL symbols making up the frequency-encoded ADSL signal (104) into a corresponding time domain signal. The transmitter (100) then interpolates the time domain signal and high pass filters the interpolated signal. This high pass filtered signal is then converted to analog form, bandpass filtered, and driven onto the telephone line (18).
Abstract:
In a communication system that employs DMT technology to couple a primary site (102) to a plurality of secondary sites (104-108), call support infrastructure is obtained as follows. Having received a call request, the primary site (102) identifies targeted subscribers and target secondary sites, i.e., the secondary sites having a targeted subscriber affiliated therewith. Next, the primary site determines a call bit loading table from the site bit loading tables of the target secondary sites. Having done this, the primary site selects, based on bandwidth requirements of the call, at least one carrier channel to provide the infrastructure support for the call.