PROVISIONAL APPliCATION FOR PATENT COVER SHEET
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`Patent and Trademark Office; U.S. DEPARTMENT OF C/O-'::;ERCE
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`This is a request for filing a PROVISIONAL APPLICATION FOR PATENT under 37 CFR 1.53(b)(2).
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`Docket Number
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`AWM-022.60
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`INVENTOR(S)! APPIlCANT(S)
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`inside this box ~
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`lAST NAME
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`FIRST NAME
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`MIDDLE INITIAL
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`RESIDENCE (CITY AND EITIIER STATE OR FOREIGN COUNTRy)
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`Gross
`Greszczuk
`Padir
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`Rick
`John
`Halil
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`Acton, Massachusetts
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`Stowe, Massachusetts
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`North Andover, Massachusetts
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`A MULTICARRIER TRANSMISSION SYSTEM wrm A LOW POWER SLEEP MODE AND WIm
`INSTANT-ON CAPABILITY
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`TITLE OF mE 1NVEN110N (280 characters max)
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`CORRESPONDENCE ADDRESS
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`STATE
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`I
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`MA
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`I ZIPCODE I
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`02109-2170
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`COUNTRY I
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`United States
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`Patent Group
`Foley, Hoag & Eliot LLP
`One Post Office Square
`Boston
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`The invention was made by an agency of the United States Government or under a contract with an agency of the United States Government.
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`No.
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`TYPEDorPruNTEDNAME~Cha~~r~le~s~H~.~C~e~l~la~ _______ __
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`Date
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`1126/98
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`REGISTRATION NO.
`(if appropriate)
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`38,099
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`D Additional inventors are being named on separately numbered sheets attached hereto.
`USE ONLY FOR FILING A PROVISIONAL APPLICATION FOR PATENT
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`295697.1
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`01/26/98 17:58 FAX 781 687 0459
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`'AWARE INC
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`Aware Company Confidential Information
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`141 008
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`Title:
`A multicarrier transmission system with a low power sleep mode and with instant-on capability.
`Authors:
`John Greszczuk, Rick Gross, Halil Padir
`Date:
`26 January 1998
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`Cross-reference to related applications
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`This application is based in part on the following patent applications:
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`U.S. Patent No. 5,497,398 dated March 5, 1996, authors Michael A. Tzannes and Marcos C. Tzannes;
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`u.s. Patent Application entitled Adaptive Allocation for Variable Bandwidth Multicarrier Communication
`filed June 12, 1997. inventors: George Kechriotis, Marcos Tzannes and Pui Wu, Serial number 08/873,421;
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`US Provisional Patent Application entitled Adaptive Allocation for Variable Bandwidth Multicarrier
`Communication filed June 12, 1996. inventors: George Kechriotis. Pui Wu and Marcos Tzannes, U.S
`provisional application Serial number 60/019.637;
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`and U.S. Provisional Application entitled: Splitteriess Multicarrier Modulation for high speed data
`transport over telephone wires. fIled October 10, 1997, inventors: Richard Gross, John Greszczuk, Dave
`Krinsky, Marcos Tzannes and Michael Tzannes, Serial number 60/061.689
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`and U.S.Provisional Application entitled: Dual Rate Multicarrier Transmission System in a Splitterless
`Configuration, flIed January 16 1998. inventors: Richard Gross and Michael Tzannes.
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`and U.S.Provisional Application entitled: Dual Rate Multicarrier Transmission System in a Splitterless
`Configuration, filed January 21 1998, inventors: Richard Gross, Marcos Tzannes and Michael Tzannes.
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`Other references:
`Patent #5428790 : Computer power management system
`INVENTORS:Harper; Leroy D., Sunnyvale, CA et al.
`ASSIGNEES:Fujitsu Personal Systems. Inc., Santa Clara, CAISSUED:June 27, 1995 FILED: Oct. 8, 1993
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`Background
`Computers for personal use have a feature whereby they can minimize their power consumption
`when not actively being used - a sleep mode. They can awaken from the sleep mode quickly, and resume
`operation when the user returns to the computer.
`For a multicarrier modem, such as described in the above cross referenced patent applications, to be
`integrated with such a computer it also needs to have such a sleep mode, during which it has reduced
`power consumption. It also must awaken quickly to begin transmitting and receiving data.
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`A large part of the power consumed by a multicarrier modem is by the transmit line driver circuit
`and by the the digital circuitry that modulates and demodulates user data. In order to minimize the power
`consumption of the modem it is necessary for the transmitter to be able to shut down and for most of the
`digital circuitry to either shut down or operate at a reduced frequency and power consumption. The current
`state of the art multicarrier modems are unpredictable when resuming from a shutdown of the normal
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`01/26/98 17:59 FAX 781 687 0459
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`"'AWARE INC
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`141 009
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`Aware Company Confidential Information
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`transmit signal and a full initialization and training sequence must be executed which requies several
`seconds.
`In central offices power consumption is also an issue, and a modem in the CO can reduce its
`power consumption when operating with a modem that is in a sleep mode, as it only has to generate a pilot
`tone, monitor the line for a signal to resume, and generate idle data for equipment connected to it.
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`Objects of the invention
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`It is an object of the invention to provide a multicarrier modem at the customer premises can
`maintain synchronization with the modem at the central office while in a low power sleep mode.
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`It is an object of the invention to provide a multicarrier modem that on awakening from sleep
`mode, can resume transmission and reception of data in a very short time , without
`requiring the normal multicarrier initialization sequence.
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`It is an object of the invention to provide a multicarrier modem that after a period of time with no
`received signal present, can resume transmission and reception of data in a very short time , without
`requiring the normal multicarrier initialization sequence.
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`It is an object of the invention that a multicarrier modem situated in a central office can operate at
`reduced power while the remote modem is in sleep mode.
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`Description of the invention
`Terms:
`The modem at the customer premises is the CPE.
`The modem at the other end, which could be a phone company's central office for instance is
`referred to as the CO modem.
`The pilot tone is an unmodulated carrier, generated by the CO modem at a frequency related to the frame
`rate.
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`Demodulation state refer to the values of adaptive parameters that are learned in the initialization
`sequence and may be monitored during normal operation. These include but are not limited to equalizer
`coefficients, echo cancellor coefficients, front end gain settings, phase locked loop phase offset and
`frequency offset values, depending on a particular implementation of a multicarrier receiver.
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`Operating state:
`The modems will have performed the initialization sequence and have trained any equalizer or echo
`cancellors for the particular channel that they are on. The CPE modem will be using a frame clock it
`recovers from the received line signal., known as loop timing. The CO modem sends a pilot tone by
`leaving one the carriers unmodulated.
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`Entering sleep state:
`This would be initiated by a signal from the main processor that the computer is idle. The CPE
`modem would signal the CO modem that it is going to enter a sleep mode. In the preferred embodiment
`this is done by passing a message in the embedded operation channel of the communications link. It also
`could be done stopping the transmission of user data and transmitting some signaling tones to the CO
`modem. When the CO modem aclmowledges the sleep mode, the CPE modem
`will power down its transmitter.
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`Operation during sleep mode:
`The CO modem will continue to transmit the pilot tone. This enables the CPE modem to
`maintain synchronization during the sleep mode. The CPE modem will maintain power to the receiver
`analog circuitry and a significantly reduced level of power to the digital circuitry, especially the digital
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`°AWARE INC
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`Aware Company Confidential Infonnation
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`141010
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`signal processing circuitry that consumes a large part of the power in nonnal operating mode. A digital
`phased locked loop (PLL) needs to be maintained to process the pilot tone and maintain synchronization
`with the CO. This involves adjusting its clock phase to maintain phase and frequency lock with the frame
`clock of the CO, and also to maintain a count of the number of frames and superframes elapsed.
`The CO modem will have to maintain its previous demodulation state, and maintain a count of the
`number of frames and superframes elapsed. It will also have to monitor the line for the appearance of the
`'awaken signal' from the remote modem. In the CO modem a large part of the digital signal processing
`circuitry can operate in a low power mode. It needs to keep power to its transmit line driver, and its other
`analog circuitry, but since only a pilot tone needs to be generated the modulation circuitry can be powered
`down. In a central office, the rest of the equipment is still operating, and while the link between the CO
`modem and the CPE modem is in a sleep state, user data provided by the CO modem will be benign idle
`data such as A TM Idle Cells or HDLC FLAG octets, and not generate false data errors to other
`equipment.
`
`Awakening from sleep mode (Initiated by the CPE):
`When initiated by the computer waking up, the CPE modem wakes up first
`and transmits a tone to the CO modem, signaling that it is about to leave sleep mode. Nonnally
`conununications could resume inunediately after a few frames. However if changes to the channel occurred
`while the modems where in sleep mode, a short reference signal for a few of frames could be used to
`verify that the communications are satisfactory before switching back to user data. If the training signal
`showed errors then a fall back to a longer retrain could be initiated by either modem. A change in the
`channel that could result in errors would be a different number of phones off-hook in a splitterless
`residential application.
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`Awakening from sleep mode (Initiated by the CO):
`The CO modem will initiate the awakening by transmitting another tone - the awaken
`tone - agreed upon with the CPE in advance. The CPE modem will also maintain power to a small amount
`of circuitry that monitors the received line signal for this awaken tone.
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`Preliminary Claims:
`A multicarrier modulation system that consists of :
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`A modem that is able to significantly reduce its power consumption, while it remains
`1.
`synchronized with the remote modem, and that after full power is resumed, can begin transmitting and
`receiving data 'instantly', -within a few frames.
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`A modem as above, that also sends a short known reference signal to verify that the demodulation
`2.
`process has sufficiently small error for reliable transmission.
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`A modem as above that can perform a retrain sequence to re-adapt to new channel characteristics
`3.
`if the existing demodulator state is producing large errors.
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`A modem that can detect a signal from the other modem, and is able to maintain it's current
`4.
`state, when the other modem stops transmitting fora time and then resumes transmission so that upon
`resumption of transmission it can 'instantly' , within a few frames, transmit and receive user data.
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`5.
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`A modem as in claim 4 , that sends the appropriate idle data to connected DTE equipment so that
`an error condition is not created when the mulicarrier system is in a sleep mode.
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`A modem as in claim 5. that also sends a short known reference signal to verify that the
`6.
`demodulation process has sufficiently small error for reliable transmission.
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`01/26/98 18:00 FAX 781 687 0459
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`'AWARE INC
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`141011
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`Aware Company Confidential Information
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`A modem as in claim 5 that can perform a retrain sequence to re-adapt to new channel
`7.
`characteristics if the existing demodulator state is producing large errors.
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`A modem as in claim 1 that while in a low power state can detect by processing the received line
`8.
`signal that the remote modem is signaling it to awaken and resume normal operation.
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`9. A modem as in claim 5, that can also signal to the other modem that it should to awaken and resume
`normal operation by transmitting a predefined signal.
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`A modem as in claim 5 , that operates with moderately reduced power consumption when
`10.
`transmitting only the pilot tone, monitoring the line for a signal to resume, and generating idle data for
`equipment connected to it.