PATENT NUMBEiR
`
`6668062,-
`
`L_
`
`(3659052
`
`ULG U
`
`ZUU
`
`s UTIITY Patent Application
`PATENT DATE
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`0.1.
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`SCANNE
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`O.A. __i!
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`71
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`-CPSM.-I
`VIC=
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`APPLicAti6N NO.
`09/Y,-)5173
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`CONY/PRIOR
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`t)
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`CLASS
`EX)4-
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`SUBCLASS
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`ART UNIT
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`EXAMINER
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`3763
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`/< /m
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`EL
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`(L<
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`ui
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`_:-:1 -JPJ
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`PT04M
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`ORIG I NAL
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`ISSUING CLASSIFICATION
`CROSS REFERENCE(S)
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`CLASS
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`SUBCLASS
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`CLASS
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`SUBCLASS (ONE SUBCLASS PER BLOCK)
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`2- z
`INTERNATIONAL rLASSIFICATJON
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`3, 20
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`2
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`Iq It- I
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`TI 7
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`TERMINAL
`DISCLAIMER
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`FI Continued on Issue Slip Inside File Jacket
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`A
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`DRAwINGS
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`CLAIMSALLgVED"
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`Sheets'Drwg.
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`Figs. DrWb.
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`Print Fig.
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`Total Claims
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`Print Claim for O.G.
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`The term of this patent
`subsequent to --- (date) 4;;Ovf"
`has been digetairnOd.
`
`(Assistani Examiner)
`
`(D a)
`
`NOTICE OF ALLOWANCE MAILED
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`0 The term ot this patent shall
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`not extend beyond the expiration date
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`of U.S Patent. No.
`
`lw_
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`-7
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`rl""
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`-
`Z"' STMtN MN
`4EMIiORY PATM UMM
`7MMOLWY OMR 2w,_
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`(PHmary Examlner)
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`(Data)
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`The lorminal --month of
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`ihis palent have been discialmed
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`WARNING:
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`hatruments Exakiner)
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`ISSUE FEE
`
`Amount Due
`W-00
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`ISSUE BATCH NUMBER
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`The Iriformatlon disclosed herein may 6a restricted, Unauthorlzed disclosure may be prohibited by the United States Code
`Flossession outside ihe U.S. Patent & Trademark Off Ice Is restricted to aothorized employees and contractors only.
`
`Tltie 35, Secticns 122, 181 and 368.
`
`6199)
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`FILED WITH: Lj DISK (CRF) F] FICHE Fl CD-ROM
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`lAitachad in pocket on dght inelde fiap)
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`ISSUE- FEE IN FILE
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`I
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`(FACE)
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`CSCO-1006
`Cisco v. TQ Delta
`Page 1 of 253
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`

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`Y4
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`INITIALP
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`Date
`Received,
`(inel. C. of M.)
`or
`Date Mailed
`
`n
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`PATENT APPLICATION
`
`c-N7u s 3
`0
`51'7 P To
`
`i
`
`09755173
`
`CONTENTS
`
`Date Received
`(incl. C. of M.)
`or
`Date Mailed
`
`.
`
`1. Application_ papers.
`
`.2.
`
`Y -f-e. C-Ot Lc(
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`LaT,020 -hiaUA
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`Lj 1mg
`A.
`Zkat -te
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`(17.
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`9
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`UAkffi
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`M Q5
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`1015..
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`e4z 'S"IM
`AM/5Vb
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`133J
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`A-7. 63
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`m ,
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`i
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`27.--
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`38--
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`39.
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`4o.-
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`Page 2 of 253
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`PATENT APPLICATION SERIAL NO.
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`U.S. DEPARTMENT OF COMMERCE
`PATENT AND TRADEMARK OFFICE
`FEE RECORD SHEET
`
`01/155J200i Mill
`
`00000094 09755173
`
`01 FLAW
`(1114".103
`01) I-N.102
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`710.00 OP
`414.00 W
`480.00 01)
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`PTO-1556
`(5/87)
`GPO: 2000460-981139595
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`Page 3 of 253
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`CONFIRMATION NO. 3915
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`CLASS
`375
`
`GROUP ART UNIT
`2634
`
`ATTORNEY DOCKET
`NO.
`081513-4
`
`STATE OR
`
`SHEETS
`
`TOTAL
`
`INDEPENDENT
`
`COUNTRY
`MA
`
`DRAWING
`2
`
`CLAIMS
`43
`
`CLAIMS
`9
`
`1
`
`11111111111111111111111111111111111111111111
`Bib Data Sheet
`
`FILING DATE
`01/08/2001
`
`RULE
`
`SERIAL NUMBER
`09/755,173
`
`APPLICANTS
`
`David M. Krinsky, Acton, MA;
`
`Robert Edmund Pizzano JR., Stoneham, MA;
`
`CONTINUING DATA
`This appin claims benefit of 60/224,308 08/10/2000
`and claims benefit of 60/174,865 01/07/2000
`
`FOREIGN APPLICATIONS `**** .... *
`
`IF REQUIRED, FOREIGN FILING LICENSE GRANTED
`05/02/2001
`
`Foreign Priority claimed
`
`35 USC 119 (a-d) conditions met
`
`yes
`
`yes
`
`r
`
`no
`
`no'
`
`Met after Allowance
`
`Venfied and Acknoyvledged
`
`Examinees Signature
`
`Initials
`
`ADDRESS
`22204
`NIXON PEABODY, LLP
`8180 GREENSBORO DRIVE
`SUiTE 800
`MCLEAN, VA
`22102
`
`TITLE
`SYSTEMS AND METHODS FOR ESTABLISHING A DIAGNOSTIC TRANSMISSJON MODE AND COMMUNICATJNG OVER
`THF-SAME
`
`FiLING FEE
`
`RECEIVED
`6962
`
`FEES: Authority has been given in Paper
`to charge/credit DEPOSIT ACCOUNT
`No.
`for following:
`No-
`
`All Fees
`
`I
`
`1. 16 Fees ( Filing
`
`F 1 .17 Fees ( Processin
`1. 18 Fees (Issue)
`
`Other
`
`Credit
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`Page 4 of 253
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`

`
`Docket No, 081513-000004
`
`SYSTEMS AND METHODS FOR ESTABLISHING A DIAGNOSTIC
`
`TRANSMISSION MODE AND COMMUNICATING OVER THE SAME
`
`5
`
`Field ot the Invention
`
`This invention relates to test and diagnostic information. ln particular, this invention
`
`relates to a robust system and method for communicating diagnostic information.
`
`10
`
`The excbange of diagnostic and test inforrnation between tra-nsceivers in a
`
`Background of the Invention
`
`telecommunications environment is an important part of a telecommunications, such as an
`
`ADSL, deployment. In cases where the transceiver connection is not performing as expected,
`
`for exainple, where the data rate is low, where there are many bit errors, or the like, it is
`
`necessary to collect diagnostic and test infonnation from the rernote transceiver. This is
`
`perforrned by dispafching a technician to the remote site, e.g., a truck roll, which is time
`
`constuning and expensive.
`
`In DSL technology, communications over a local subscriber loop between a central
`
`office and a subscriber premises is accomplished by modulating the data to be transmitted
`
`onto a multiplicity of discrete frequency carriers wbich are summed together and then
`
`O transmitted over the subscriber loop. Individually, the carriers form discrete, non-
`
`overlapping communication subchannels of limited bandwidth. Collectively, the carriers
`
`form what is effectively a broadband communications channel. At the receiver end, the
`
`carriers are demod-alated and the data recovered.
`
`DSL systems experience disturbances from other data services on adjacent phone
`
`25
`
`lines, sucb as, for example, ADSL, HDSL, ISDN, TI, or the like. These disturbances may
`
`commence after the subject ADSL service is already initiated and, since DSL for intemet
`
`access is envisioned as an always-on service, the effect of these disturbances must be
`
`ameliorated by the subject ADSL transceiver.
`
`tLi
`
`SUMMARY OF THE IWENTION
`
`The systems and rnethods of this invention are directed toward reliably exchanging
`
`diagnostic and test infonnation between transceivers over a digital subscriber line in the
`
`presence of voice communications and/or other disturbances. For simplicity Of Teferetice, the
`
`NVA165661.1
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`Page 5 of 253
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`-2-
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`systems a-nd methods of the invention will hereafter refer to the transceivers generically as
`moderns. One such modem is typically located at a customer prtmises such as a home or
`
`business and is "downstream" from a central office with which it communicates. The otber
`
`modem I's typically located at the central office and is "upstream" from the customer
`
`5
`
`premises. Consistent with industry practice, the modems are often referred to as "ATU-W'
`
`("ADSL transceiver unit, remote," i.e., located at the customer premises) and "ATU-C"
`
`("ADSL transceiver unit, central office" i.e., located at the central office), Each modem
`
`includes a transmitter section for transmitting data and a receiver section for receiving data,
`
`and is of the discrete multitone type, i.e., the modem transmits data over a multiplicity of
`
`10
`
`subchannels of limited bandwidth. Typically, the upstream or ATU-C modem transmits data
`
`to the downstream or ATU-R modem over a first set of subchannels, which are usually the
`
`higher- frequency subchannels, and receives data from the downstream or ATU-R modem
`
`over a second, usually smaller, set of subehannels, commonly the lower-frequency
`
`subchannels. By establishing a diagnostic link mode between the two modems, the systems
`
`15
`
`and methods of this invention are able to exchange diagnostic and test i-nforrnation in a
`
`sirnple and robust manner.
`
`In the diagnostic li-nk mode, the diagnostic and test information is communicated
`
`using a signaling mechanism that has a very high immunity to -noise and/or other disturbances
`
`and can therefore operate effectively even in the case where the modems could not actually
`
`20
`
`establish an acceptable connection in their norrnal operational mode.
`
`For example, if the ATU-C and/or ATU-R modem fail to complete an initialization
`
`sequence, and are thus unable to enter a normal steady state communications mode, where the
`
`diagnostic ai-id test inforrnation would normally be exchanged, the modems according to the
`
`systems and methods of this invention enter a robust diagnostic link mode. Altematively, the
`
`25
`
`diagnostic link mode can be entered automatically or manually, for example, at the direction
`
`ofauser. In the robust diagnostic link mode, the modems exchange the diagnostic and test
`infortnation that is, for example, used by a technician to determine the cause of a failure
`
`without the technician having to physically visit, i.e., a trackroll to, the remote site to collect
`
`data.
`
`30
`
`The diagnostic and test information can include, for example, but is not limited to,
`
`signal to noise ratio information, equalizer infoiTnation, programmable gain setting
`
`infonnation, bit allocation inforination, transmitted and received power information, margin
`
`infortnation, status and rate infonnation, telephone line condition information, such as the
`
`length of the line, the number and location of bridged taps, a wire gauge, or the like, or any
`
`NVA1656611
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`Page 6 of 253
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`-3-
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`other known or later developed diagnostic or test infonnation that may be appropriate for the
`
`particular communications environment. For example, the exchanged diagnostic and test
`
`information can be directed toward specific limitations of the modems, to infon-nation
`
`relating to the modem installation and deployment environment, or to other diagnostic and
`
`test information that can, for example, be determined as needed which may aid in evaluating
`
`the cause of a soccific failure or problem. Altematively, the diagnostic and test infonnation
`
`can include the loop length and bridged tap length estimations as discussed in copending
`
`Attomey Docket No. 081513-000003, filed herewith and incorporated herein by reference in
`
`its entirety.
`
`10
`
`For example, an exemplary embodiment of the inventio-n illustrates the use of the
`
`diagnostic linlc mode in the communication of diagnostic information from the remote
`
`terminal (RT) transceiver, e.g., ATU-R, to the central office (CO) transceiver, e,g., ATU-C.
`
`Transmission of information from the remote terminal to the central office is important since
`
`a typical ADSL service provider is located in the central office and would therefore benefit
`
`from the ability to deterrnine problems at the remote terminal without a truckroll. However,
`
`it is to be appreciated, that the systems and the methods of this invention will work equally
`well in communications from the central office to the remote terminal.
`
`These and other features and advantages of this iiivention are described in or are
`
`apparent from the following detailed description of the en-ibodiments.
`
`i z
`
`15
`
`20
`
`13RIEF DESCRIPTION OF THE DRAWINGS
`
`The embodiments of the invention will be described in detail, with reference to the
`following figur s wherein,
`
`Fig.
`
`izrs 'a,' functional block diagram illustrating an exemplary communications system
`
`25
`
`according to this invention; and
`
`is a flowchart outlining an exemplary method for communicating diagnostic
`Fig.
`and test infonnation according to this invention.
`
`DETAILED DESCRIPTION OF THE INVENTION
`
`30
`
`Foy ease of illustration the following description will be'described in relation to the
`
`CO receiving diagnostic and test information from the RT. In the exemplary embodiment,
`
`the systems and methods of this invention complete a portion of the normal modem
`
`initialization before entering into the diagnostic link mode. The systems and methods of this
`
`iiivention can enter the diagnostic link mode manually, for example, at the direction of a
`
`NVA165661 I
`
`Page 7 of 253
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`-4-
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`technician or a user after completing a portion of initialization, Altematively, the systems
`
`and methods of this invention can enter the diagnostic link mode automatically based on, for
`
`example, a bit rate failtire, a forward error correction or a CRC error during showtime, e.g.,
`
`the nonnal steady state transmission mode, or the like. The transition iuto the diagnostic link
`
`5
`
`mode is accomplished by transmitting a message from the CO modem to the RT modem
`
`indicating that the modems are to enter into the diagnostic link mode, as opposed to
`
`transitioning into the normal steady state data transmission mode. Altematively, the
`
`transition into the diagnostic link mode is accomplished by transmitting a message from the
`
`RT modem to the CO modem indicating that the modems are to enter into the diagnostic link
`
`10
`
`mode as opposed to transitioning into the norinal steady state data transmission mode. For
`
`example, the transition signal uses an ADSL state transition to tra-nsition from a standard
`
`ADSL state to a diagnostic link mode state.
`
`In the diagnostic link mode, the RT modem sends diagnostic and test infonnation in
`
`the form of a collection of information bits to the CO modem that are, for example,
`
`modulated by using onr, bit per DTM symbol modulation, as is used in the C-Rates I message
`
`in thi-, TTU and ANSI ADSL standards, where the symbol may or may not include a cyclic
`
`prefix. Other exemplary modulation techniques include Differential Phase Shift Keying
`
`(DPSK) on a subset or all the carriers, as specified in, for example, ITU standard G.994. 1,
`
`higher order QAM modulation (>I bit per carrier), or the like.
`
`20
`
`In the one bit per DMT symbol modulation message encoding scheme, a bit with
`
`value 0 is mapped to the REVERB I signal and a bit witb a value of 1 mapped to a SEGUE 1
`
`signal. The REVERB I and SEGUEI signals are defined in the ITU and ANSI ADSL
`
`standards. The R-EVERB I signal is generated by modulating all of the carriers in the
`
`multicarrier system with a known pseudo-random sequence thus generating a wideband
`
`25
`
`modulated signal. The SEGUEI signal is generated from a carrier by 180 degree phase
`
`reversal of the REVERB I signal. Since both signals are wideband and Imown in advance,
`
`the receiver can easily detect the REVERB I and SEGUEI signal using a simple matched
`
`filter in the presence of large amounts of noise and other disturbances.
`
`30
`
`35
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`NVA165661.1
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`Page 8 of 253
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`

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`i
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`- 5 -
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`Exemplary Message Variables
`Data Sent in the Diag Link
`Train Type
`ADSL Standard
`Chip Type
`Vendor ID
`Code Version
`Average Reverb Received Signal
`Profranunable gain amplifier (PGA) Gain Training
`Programmable gain amplifier PGA Gain Showtime
`Filter Present during Idle Channel Calculation
`Average Idle Channel Noise
`Signal to Noise during Training
`Signal to Noise during Showtime
`Bits and Gains
`Data Rate
`Framing Mode
`Margin
`Reed-Solomon Coding Gain
`QAM Usage
`Frequency Domain Equalizer (FDQ) Coefficients
`Gain Scale
`Time domai-n equalizer (TDQ) Coefficients
`Digital Echo Canceller (DEC) Coefficients
`Table I
`Table I shows an example of a data message that can be sent by the RT to the CO
`
`S
`
`during the diagnostic link mode. In this example, the RT modem sends 23 different data
`
`variables to the CO. Eacb data variable contains different items of diagnostic and test
`
`information that are used to analyze the condition of the link. The variables may contain
`10 more than one item of data. For example, the Average Reverb Signal contaiTis the power
`
`levels per tone, tip to, for example, 256 entries, detected during the ADSL Reverb signal.
`
`Conversely, the PGA Gain Training is a single entry, denoting the gain in dB at the receiver
`
`during the ADSL training.
`
`Many variables that represent the type of diagnostic and test infonnation that are used
`
`15
`
`to analyze the condition of the link are sent from the RT modem to the CO modem. These
`
`variables can be, for example, arrays with different lengths depending on, for example,
`
`infon-nation in the initiate diagnostic mode message. The systems and methods of this
`
`invention can be tailored to contain many different diagnostic and test information variables,
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`NVA165661 I
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`Page 9 of 253
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`WON
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`Tbus, the system 'Is fully configurable, allowing stibsets of data to be se-nt and addit'lonal data
`
`variables to be added in the future. Therefore, the message length can be increased or
`
`decreased, and diagnostic and test inforrnation customized, to sLipport more or less variables
`
`as, for example, hardware, the environment and/or the telecommunications equipment
`
`5
`
`dictates.
`
`Therefore, it is to be appreciated, that in general the variables transmitted from the
`
`modem being tested to the receiving modem can be any combination of variables which
`
`allow for transrnission of test and/or diagnostic information.
`
`Fig. I illustrates an exemplary embodiment of tl-ie additional modem components
`
`10
`
`associated with the diagnostic link mode. In particular, the diagnostic link system 100
`
`compnses a central office modem 200 and a remote terminal modem 300. The central office
`
`modem 200 comprises, in addition to the standard ATU-C components, a CRC checker 210,
`
`a diagnostic device 220, and a diagnostic inforrnation monitoring device 230. The remote
`
`terrninal modem 300 comprises, in addition to the standard components associated with an
`
`15
`
`ATU-R, a message determination device 3 10, a power control device 320, a diagnostic device
`
`330 and a diagnostic infonnation storage dovice 340. The central office modem 200 and the
`
`remote terminal model 300 are also connected, via link 5, to a splitter 10 for a phone switch
`
`20, and a splitter 30 for a phone 40. Altematively, the ATU-R can operate without a splitter,
`
`e.g., splitterless, as specified in ITU standard G.992.2 (G.11te) or with an in-line filter in series
`
`20
`
`with the phone 40. In addition, the reniote terminal modem 300, can also be connected to, for
`
`example, one or more user terminals 60. Additionally, the central office modem 200 can be
`
`connected to one or more distributed networks 50, via link 5, which may or may not also be
`
`connected to one or more other distributed networks.
`
`While the exemplary embodiment illustrated in Fig. I shows the diagnostic link
`
`25
`
`system 100 for an embodiment in which the remote tenninal modem 300 is communicating
`
`test and diagnostic information to the central office 200, it is to be appreciated that the
`
`various components of the diagnostic link system can be rearranged such that the diagliostic
`
`and test information can be forwarded from the central office 200 to the remote terminal
`
`modem 300, or, altematively, such that both modems can send nd receive diagnostic and/or
`
`30
`
`test information. Furthcrmore, it is to be appreciated, that the components of the diagnostic
`
`link system 100 can be located at various locations within a distributed network, such as the -
`
`POTS network, or other comparable telecommunications network. Tbus, it should be
`
`appreciated that the components of the diagnostic tink system 100 can be combi-ned into one
`
`device for respectively transmitting, receiving, or transrnitting aiid receiving diagnostic
`
`NVA165661 1
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`Page 10 of 253
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`7-
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`and/or test information. As will be appreciated from the following description, and for
`
`reasons of computational efficiency, the components of the diagnostic link system 100 can be
`
`arranged at any location within a telecommunications network and/or modem without
`
`affectirig the operation of the system.
`
`The links 5 ca-n be a wlyed or wireless link or a-ny other k-nown or later developed
`
`element(s) that is capable of supplying and communicating electronic data to a-nd from the
`
`connected elements. Additionally, the user terminal 60 can be, for example, a personal
`
`computer or other device allowing a user to interface witli and communicate over a modem,
`
`such as a DSL modem. Furthermore, the systems and method of this invention will work
`
`10
`
`equally well with splitterless and low-pass mulitearrier modem technologies.
`
`In operation, the remote terminal 300, commences its non-nal initialization sequence.
`
`The diagnostic device 330 monitors the initialization sequence for a failure. If there is a
`
`failure, the diagnostic device 330 iTiitiates the diagnostic link mode. Altematively, a user or,
`
`for exatnple, a technician at the CO, cari specify that the remote terminal 300 enter into the
`
`i15
`
`diagnostic link mode after completing a portion of an initialization. Altematively still, the
`
`diagnostic device 330 ca-n monitor the norrnal steady state data transmission of the remote
`
`tertninal, and upon, for example, an error threshold being exceeded, the diagnostic device 330
`
`will initiate the diagnostic link mode.
`
`Upon initialization of the diagnostic link mode, the diagnostic device 330, in
`
`20
`
`cooperation with the remote tertninal 300 will transmit an initiate diagnostic link mode
`
`message from the remote terminal to the central office 200 (RT to CO). Altematively, the
`
`central office modem 200 can transmit an initiate diagnostic link mode message to the remote
`
`terminal modem 300. If the initiate diagnostic li-nk mode message is received by the central
`
`office 200, the diagnostic device 330, in cooperation with the message detennination device
`
`25
`
`310, detennines a diagnostic link mcssage to be forwarded to the central office 200. For
`
`example, the diagnostic link message can include test information that has been assembled
`during, for example, the normal ADSL ilriltialization procedure. The diagnostic and/or test
`
`information can include, but is not limited to, the version number of the diagnostic link mode,
`
`the length of the diagnostic and/or test information, the cormnunications standard, such as the
`
`30
`
`ADSL standard, the chipset type, the vendor identifications, the ATU version number, the
`
`time domain received reverb signal, the frequency domain reverb signal, the amplifier
`
`settings, the CO transmitter power spectral density, the frequency domain received idle
`
`channel, the signal to noise ratio, the bits and gains and the upstream and doNvnstream
`
`transmission rates, or the like.
`
`NVA165661.1
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`Page 11 of 253
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`-8-
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`If the initiate diagnostic link mode message is not received by the central office 200,
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`the li'litiate diagnostic link mode rnessage can, for example, be re-transmitted a predetermined
`
`number of iterations until a deterrnination is made that it is not possible to establish a
`
`connection.
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`AssuTning the initiate diagnostic link mode message is received, then, for a
`
`predetermined number of iterations, the diagnostic device 330, in cooperation with the remote
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`terminal modem 300 and the diagnostic informa'tion storage device 340, transmits the
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`diagnostic link message with a cyclic redundancy check (CRC) to the central office modem
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`200. Ilowever, it is to be appreciated that i-n general, any error detection sebeme, such as bit
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`10
`
`error detection, can be used without affecting the operation of the system. The central office
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`200, in cooperation with the CRC checker 210, determines if the CRC is correct. If the CRC
`
`is correct, the diagnostic information stored in the diagnostic information storage device 340
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`has been, witb the cooperation of the diagnostic device 330, and tbc remote terminal modem
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`300, forwarded to the central office 200 successfully.
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`5
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`If, for example, the CRC chi2cker 2 10 is unable to determine the correct CRC, the
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`diagnostic device 330, in cooperation with power control device 320, increases the
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`transmission power of the remote terminai 300 and repeats the transmission of the diagnostic
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`link message from the remote terminal 300 to the central office 200. This process continues
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`until the correct CRC is detennined by the CRC checker 210.
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`The rnaximum power level used for transmission of the diagnostic link message can
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`be specified by, for example, the user or the ADSL service operator. If the CRC checker 210
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`does not determine a correct CRC at the maximum power level and the diagnostic link mode
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`can not be initiated then other methods for determining diagnostic information are utilized,
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`such as dispatching a technician to the remote site, or the like.
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`25
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`Alternatively, the remote ten-ninal 300, with or without an increase in the power level,
`
`can transmit the diagnostic link message several times, for example, 4 times. By transmitting
`
`the diagnostic link rnessage several tirnes, the CO modem 200 can use, for example, a
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`diversity combining scheme to improve the probability of obtaining a correct CRC from the
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`received diagnostic link message(s).
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`30
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`Alternatively, as previously discussed, the central office 200 comprises a diagnostic
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`information monitoring device 230. The remote terminal 300 can also include a diagnostic
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`infonnation monitoring device. One or more of these diagnostic information monitoring
`
`devices can monitor the normal steady state data transrnission between the remote terrninal
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`300 and the central office 200. Upon, for example, the norinal steady state data transrnission
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`exceeded a predetermined error threshold, the diagnostic information monitoring device can
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`initiate the diagnostic link mode with the cooperation of the diagnostic device 300 and/or the
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`diagnostic device 220.
`
`Fig. 2 illustrates an exemplary method for entering a diagnostic link mode in
`
`accordance with this invention. In particular, control begins in step SIOO and coritinues to
`stepSI10. Instep SIIO, the initialization sequence is commenced, Next, instep S120, ifan
`initialization failure is detected, control continues to step S170, Otherwise, controljumps to
`
`stepS130. Instep S130, a determination is made whether the diagnostic link mode has been
`
`selected. If the diagnostic link mode has been selected, control conti-nues to step S 170,
`
`10
`
`otherwise, control jumps to step S 140.
`
`In step S 170, the initiate diagnostic link mode message is transmitted from, for
`
`example, the remote terminal to the central office. Next, in step S 180, a determination is
`
`made whether the initiate diagnostic mode message has been received by the CO. if the
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`initiate diagnostic mode message has been received by the CO, control j'umps to step S200.
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`Otherwise, control continues to step S190. ln step S190, a deterrnination is made whether to
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`re-transmit the initiate diagnostic mode message, for example, based on whether a
`
`predetermined number of iterations have already been completed. If the initiate diagnostic
`
`mode message is to be re-transmitted, control coiitinues back to step S 170. Otherwise,
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`control jumps to step S 160.
`
`ln step S200, the diagnostic link message is determined, for example, by assembling
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`test and diagnostic information about one or more of the local loop, the modem itself, the
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`telephone network at the remote terminal, or the like. Next, in step S21 0, for a predetermined
`
`number of iterations, steps S220-S240 are completed. In particular, in step S220 a diagnostic
`
`link message comprising a CRC is transmitted to, for exai-nple, the CO. Next, in step S230,
`the CRC is determined. Then, in step S240, a detennination is made whether the CRC is
`
`25
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`correct. If the CRC is correct, the test and/or diagnostic information has been successfully
`
`communicated and control continues to step S 160.
`
`Otherwise, if step S210 has completed the predetermined number of iterations, control
`
`continues to step S250. In step S250, the transmission power is increased and control
`
`30
`
`continues back to step S2 10, Altematively, as previously discussed, the diagnostic link
`
`message may be transmitted a predetennined number of times, with our without a change in
`
`the transmission power.
`
`In step S 140, the normal steady state data transmission is entered into between two
`
`modems, such as the remote tertninal and the cental office modems. Next, in step S150, a
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`detennination is made whether an error threshold during the normal steady state data
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`transmission has been exceeded. If the error threshold has been exceeded, cointrol continiies
`tostepS170. Otherwise, control jumps to step S160. Instep S160, the control sequence
`
`ends.
`
`5
`
`As shown in Fig. 1, the diagnostic link mode systetn can be implemented either on a
`
`single program general purpose computer, a modem, such as a DSL modem, or a separate
`
`program general purpose computer having a communications device. However, the
`
`diagnostic link system caii also be impletnented on a special purpose computer, a
`
`programmed microprocessor or microcontroller and peripheral integrated circuit element, an
`
`10
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`ASIC or other integrated circuit, a digital signal processor, a hardwired electronic or logic
`
`circuit such as a discrete element circuit, a programmed logic device such as a PLD, PLA,
`
`FPGA, PAL, or the like, and associated communications equipment. In general, any device
`
`capable of implementing a finite state machine that is capable of implementing the flowchart
`
`illustrated in Fig. 2 can be used to implement a diagnostic link system according to this
`
`invention.
`
`Furthermore, the diseloscd method may be readily implemented in software using
`
`object or object-oriented software development enviromnents that provide portable source
`
`code that can be used on a variety of computcr, workstation, or modem bardware platforms.
`
`Altematively, the disclosed diagnostic link system may be itTiplemented partially or fully in
`
`hardware using standard logic circuits or a VLSI design, Other software or hardware can be
`
`used to implement the systems in accordance with this iilvention depe-nding on the speed
`
`and/or efficiency requirements of the systems, the particular function, and a particular
`
`software or hardware systems or microprocessor or microcomputer systems being utilized.
`
`The diagnostic link system and methods illustrated heTein however, ca-n be readily
`
`25
`
`implemented in hardware and/or software using any known or later developed systems or
`structures, devices and/or software by those of ordinary skill in the applicable art from the
`
`functiolial description provided herein and with a general basic knowledge of the computer
`
`and telecommunications arts.
`
`Moreover, the disclosed methods can be readily implemented as software executed on
`
`30
`
`a programmed general purpose coniputer, a special purpose computer, a microprocessor, or
`
`the like. In these instances, the methods and systems of this invention can be implemented as
`
`a program embedded on a modem, such a DSL modem, as a resource residing on a personal
`
`computer, as a routine embedded in a dedicated diagnostic link system, a central office, or the
`
`like. The diagnostic link system caii also be -implemented by physically incorporating the
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`system and method into a software and/or hardware system, such as a hardware and software
`
`systems of a modem, a general purpose computer, an ADSL line testing device, or the like.
`
`It is, therefore, apparent that there is provided in accordance with the present
`
`invention, systems and methods for transmitting a diagnostic link message. While this
`
`5
`
`invention has been described in conjunction with a number of embodiments, it is evident that
`
`many altematives, modifications and variations would be or are appare-nt to those of ordinary
`
`skill in the applicable arts. Accordingly, applicants intend to embrace all such altematives,
`
`modifications, equivalents a-nd variations that are within the spirit and the scope of this
`
`invention.
`
`I
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`What is Claimed is:
`A
`
`1,
`
`diagnos'ic 'il'ys'em
`multicarrier modulation comor
`n2-
`
`for communicating data between modems using
`
`aTi initiate
`
`mode trigger that instructs a transmitti-ng modem to
`
`5
`
`forward an initiate diagnostic
`
`message to a receiving modem;
`
`a message aetermir
`
`device that detennines a diagnostic link message; and
`
`a receiving modem
`
`device that receivcs the diagnostic link message
`
`and determines the accuracy of the agnostic link message.
`
`2.
`
`The system of cli im 1, fu-rther comprising a power control device that
`
`10
`
`increases a transmission power
`
`eejagnostic link message if the received diagnostic link
`
`message is inaccurate.
`
`CtA
`
`3.
`
`The
`
`predetermined number of -mes.
`system Of Claim
`
`1, wherein the diagnostic link message is re-transmitted a
`
`The system of claini 1, wherein the diagnostic link message comprises at least
`
`one of test and diagnostic
`
`The system of claim , wherein the diagnostic link message comprises at least
`
`one of a version number of a diagn stic link mode, a length of the diagnostic information, a
`
`communications standard, a chipset ype, one or more vendor ide-ntifications, an ATU version
`
`number, a time domain received rev rb signal, a frequency domain reverb signal, an amplifier
`
`setting, a CO transmiUer power spec
`
`density, a frequency domain received idle channel, a
`
`rmation, and upstream and downstream transmission
`signal to noise ratio, bits and gai-n in
`ral
`'c
`'t
`
`rates.
`
`The system of claim 1,1wherein the accuracy is deterruined based on at least
`
`one of an error detecting scheme, a bi
`
`tion
`
`a cyclic redundancy check.
`
`25
`
`.
`
`The system of claim 1, h ein the
`
`er is based on at least one of an
`
`initialization failure, a bit rate failure,
`
`'
`
`'
`
`a
`C C eirror 1
`trig
`an iiinitialization message, a CRC error
`
`during a normal s