Ikanos Communications, Inc.

Ricochet Networks, Inc.

Ikanos Technology Ltd.

Hojat Khelghati

Sam Heidari

Behrooz Rezvani

Yuwen Su

Qasem Aldrubi

John Gevargiz

Rodrigo Garces

Fernando Ramirez-Mireles

Christopher Chow

Saman Behtash

Alfred K Mui

Jalal O Azim

Mazen M Shihabi

Avadhani Sridhar

Padmasheela Rayala

Christopher M Chow

A transceiver having shared and discrete components forming a transmit path and a receive path configured to couple to a subscriber line for establishing a communication channel with a remote transceiver. The transceiver comprises a pseudo link manager coupled between the transmit and receive path components to manage pseudo links on the subscriber line prior to entry into a session with the remote transceiver. The pseudo link manager includes: a line monitor and a disruptor. The line monitor monitors the subscriber line, prior to initiating a session, for a received communication signal indicative of a pre-existing session on the remote transceiver. The disruptor transmits a disruptor signal over the subscriber line to the remote transceiver responsive to the detection by the monitor of the received communication signal; thereby disrupting the remote transmitter's pre-existing session and allowing a new session to be established with the remote transceiver.

Method and apparatus for managing XDSL pseudo links

The present invention provides a method and apparatus for demodulating data received over a communication medium carrying a transmission having multiple pilot tones with pilot data modulated thereon and message tones with message data modulated thereon and with the pilot tones and message tones frequency division multiplexed with respect to one another. In an embodiment of the invention the communication protocol utilized for modulation and demodulation is discrete multi tone (DMT). The invention allows message processing and equalizer training to proceed in parallel before equalizer training tables have been completed thus reducing the time associated with modem initialization. The apparatus in one embodiment of the invention includes on the receive path of a DMT or other multi-tone modem, a fast Fourier transform engine (FFT), a message processor, and a decoder. The FFT converts the received data from a time domain to a frequency domain. The received data in the frequency domain includes successive sets of pilot tones together with message tones. The message processor selects pairs of message and pilot tones proximate to one another in the frequency domain in each set of pilot tones and message tones. The message tone in each pair is then equalized with the pilot tone in the pair to substantially remove frequency dependent phase shifts imparted by the communication medium to the message tone. The equalized message tone is then decoded in the decoder to the corresponding specific set of message data which it represents.

Method and apparatus for initializing modem communications

The current invention provides a method and apparatus for wireline characterization is disclosed. The method may be implemented with any modulation protocol but is particularly suited for multi-carrier modulation protocols such as discrete multi-tone (DMT). The apparatus may be incorporated into physical or logical modems. In an embodiment of the invention an apparatus for wireline characterization in a modem with a transmit path and a receive path each configured to couple with a remote modem via a wireline in which available communication bandwidth is split into a number of independent sub-channels is disclosed. The apparatus comprises: a tone selector, a cumulative loss estimator and a shift register. The tone selector selects a subset of the number of sub-channels within the bandwidth of a received wireline communication for which subset the sum of the square roots of the corresponding sub-channel indices may be expressed as an integer power &ldquo;n&rdquo; of 2. The cumulative loss estimator cumulates the insertion losses across the selected subset of the sub-channels and outputs a binary value corresponding thereto. The shift register couples to the cumulative loss estimator to scale a magnitude of the binary value received from the cumulative loss estimator by an amount proportionate to &ldquo;n&rdquo; to obtain a scaled electrical distance estimate for the wireline. Corresponding method and means are disclosed.

Method and apparatus for wireline characterization

The current invention provides a method and apparatus for determining insertion loss in wireline communication systems. The method may be implemented with any modulation protocol but is particularly suited for multi-carrier modulation protocols such as discrete multi-tone (DMT). The method for calculation of the insertion loss uses a received signal and a discrete subset of frequency ranges, e.g. DMT tones, within that signal. For each of the subset of frequency ranges the average received power on each of the selected set of tones is determined. Next the average power on each received subset of tones is converted to log using a simple log estimation circuit that avoids the complexity associated with log tables and other prior art methods of computing logarithms. Then the sum of the log of the average power received in each of the selected subset of tone bins is determined. Next, the known transmitted power for the selected subset of tones is expressed as log , is summed and is then subtracted from the sum of the log of the average power received. Then using a simple electrical length estimation circuit the insertion loss is calculated. A corresponding apparatus is disclosed.

Method and apparatus for insertion loss estimation in wireline communications

A method and a system are provided to determine and thus select the best choice for antenna to be used by a network device having a plurality of directional antennas for a particular sending source. The determination is made using on a metric based on the success rate of packets received at a particular directional antenna from the sending source and secondarily on a received signal strength indicator. The determination is stored and made available for processing such that a router is able to request communication through a device with a destination via the second wireless communication device without knowledge of the best antenna match. In a specific method the first communication device broadcasts packets, via each associated directional antenna, to query for the existence of the second wireless communication devices. The first device then receives a plurality of information packets about existence of the second wireless communication devices in response to the broadcast packets or in response to a query about third parties. As between each directional antenna and each second wireless communication device, a packet success metric is determined for each directional antenna, which becomes the basis for antenna selection.

Method and apparatus for selecting a directional antenna in a wireless communication system

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San Jose, CA, United States of America

Hojat Khelghati