US007835430B2
`
`(12) United States Patent
`Krinsky et al.
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 7,835,430 B2
`*Nov. 16, 2010
`
`(54) MULTICARRIER MODULATION
`MESSAGING FOR FREQUENCY DOMAIN
`
`. . . . . . .. None
`(58) Field of Classification Search . . . . . . . . .
`See application fi e for complete search history.
`
`RECEIVED IDLE CHANNEL NOISE
`INFORMATION
`
`(56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`(75)
`
`Inventors: David M. Krinsky. Acton, MA (US);
`Robert Edmund Pizzano, Jr‘,
`Stoneham, MA (US)
`
`4,385,384 A
`
`5/ 983 Rosbury et al.
`(Continued)
`
`(73) Assignee: Aware, Inc., Bedford, MA (US)
`
`EP
`
`FOREIGN PATENT DOCUMENTS
`0889615
`1/1999
`
`( * ) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U-3-C 154(b) by 0 days
`
`_
`(commued)
`OTHER PUBLICATIONS
`
`This patent is subject [0 a lermjnai dis.
`Ciaimen
`
`Official Action for European Patent Application No. EP 06022008,
`mailed Apr. 23, 2010.
`
`(21) App1_ Na; 12/477,742
`
`(22)
`
`Filed:
`
`Jun. 3, 2009
`
`(65)
`
`Prior Publication Data
`US 2009/0238254 A1
`3613. 24, 2009
`
`Related US. Application Data
`(60) Continuation of application No. 10/619,691, filed on
`M 16~ 2003: W 1”“ N°~ 7v57°=686= which is a
`division ofapplication No. 09/755,173, filed on Jan. 8,
`200 1
`P N 6 6 R 8 052
`’ now at’
`O’
`’ “
`’
`'
`Prgvjgjgngfl appficmjon N0. 60,/224303, filed 0nAug.
`10, 2000‘ provisional appiication No. 60/174,365,
`filed on Jan. 7) 2000.
`
`(50)
`
`(51)
`
`[nt_ CL
`(200601)
`H04B 1/38
`(2006.01)
`H04L 12/26
`(52) U.S. Cl.
`..................................... .. 375/222; 370/252
`
`(Continued)
`
`Primary Examiner Khanh C Tran
`(74)At(omey, Agent, or1*'irm—.lason H. Vick; Sheridan Ross,
`RC.
`
`(57)
`
`ABSTRACT
`
`Upon detection of a trigger, such as the iexceedingiof an error
`threshold or the direction of a user, a diagnostic link system
`enters a diagnostic information transmission mode. This
`diagnostic information transmission mode allows for two
`modems to exchange diagnostic and/or test infomiation that
`may not otherwise be exchangeable during normal commu-
`in.Ct2.mt0:1i'bl'1:e dfaglitqstgc u.m?tr.H1tandO.n tra{1:lE1i1.S1Si1{On Igode is
`iii a 3e§§i’i3i§“ 11]1l;Ti(:ii1H;lC::JIti1 Lafi‘§3”£$ $2
`feifiii
`}.
`g
`V
`g
`.
`.
`P
`‘
`dancy check (CRC). The receiving modem determines, based
`on the CRC, if a robust communications chamiel is present. If
`a robusticommunications channel is present, the two modems
`can initiate exchange of the diagnostic and/or test infonna-
`tion. Otherwise, the transmission power of the transmitting
`modem is increased and the initiate diagnostic link mode
`message re—transmitted to the receiving modem until the CRC
`is determined to be correct.
`
`6 Claims, 2 Drawing Sheets
`
`300
`'
`
`
`
`Remote Terminal
`310
`
`(AT“'R)
`3§0
`Message M
`Diagnostic
`page,-minaiion
`
`
`
`
`1 0
`
` Device D9Vi°9
`fl/
`
`Splitter i 340
`
`/V
`
`DB9nos.“
`Information
`i Storage
` Phone
`
`
`
`Deivce
`
`5
`
`50
`. //
`
`“Q”?I,
`
`(ATU-C)
`
`210
`/9’
`CRC
`Checker
`
`Diagnostic
`Information
`MoniloriI19
`Device
`
`Diagnostic
`Device
`
`Phone
`Switch
`
`//
`
`(2560-1001
`
`Cisco v. TQ Delta
`
`Page 1 of 9
`
`CSCO-1001
`Cisco v. TQ Delta
`Page 1 of 9
`
`

`
`US 7,835,430 B2
`Page 2
`
`US. PATENT DOCUMENTS
`
`........ .. 340/539.1
`
`OTHER PUBLICATIONS
`
`Boets P. et al.: “Modeling Aspect of Transmission Line Networks”
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`XP000343913 ISBN: 0/7803—0640—6.
`
`1/1986 lV1izun0 et al.
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`10/1999 Caswell et al.
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`6/2000 I iu et al.
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`6/2000 Kao et al.
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`1/2001 Hershey et al.
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`4/2001 VVu
`6,219,378 B1
`6/2001 Chow ....................... .. 375/219
`6.249.543 B1*
`6/2002 Jcnness
`6,404,774 B1
`6/2002 '1omlinson, Jr. et al.
`6,411,678 B1
`9/2002 I_iang et al.
`.............. .. 379/1.04
`6,445,773 B1 "‘
`9/2002 Ishikawa et al.
`6,449,307 B1
`1/2003 Mirlakhraei
`6,512,789 B1
`10/2003 1\Iilbrandt
`6,631,120 B1
`10/2003 lV1ilbra.ndt
`6.633.545 Bl
`l0/2003 Milbrandt
`6,636,603 B1
`12/2003 Krinsky et al.
`6,658,052 B2
`4/2004 I_ong et al.
`6,725,176 B1
`8/2004 Korkosz et al.
`6,781,513 B1 *
`8/2009 Krinsky et al.
`7.570.686 B2
`FOREIGN PATENT DOCUMENTS
`2303032
`2/1997
`GB
`IIEI6(1994)-003956
`1/1994
`JP
`JP A—HEI10(1998)—
`513522
`12/1993
`JP A-l—1l:'111(1999)-
`508417
`JP A-IIEI11(1999)-
`261665
`JP A-HEI11(1999)-
`317723
`W0
`WO 86/07223
`W0
`W0 97/01900
`W0
`W0 99/20027
`W0
`W0 99/25375
`W0
`W0 99/63427
`W0
`W0 99/57390
`W0
`W0 00/04130
`
`7/1999
`
`9/1999
`
`11/1999
`12/1986
`1/1997
`4/1999
`5/1999
`12/1999
`12/1999
`10/2000
`
`Ciolli, John M.. ADSL Maintenance with DMT, TlE1.4 ADSL
`Project, Amati CommunicationsCorporation. Dec. 1, l992,pp. l-14.
`Lewis L. et al. “Extending Trouble Ticket System to Fault Diagnos-
`tics” IEEE ,\Ietwork, IEEE Inc. New York, US, Nov. 1. 1993, pp.
`44-51. X1’ 000575228.
`International Search Report for PCT/USOI//00418 dated Jul. 16,
`2001; 4 pages.
`Written Opinion for International (PCT) Patent Application No.
`PCT/US01/00418, completed Mar. 9, 2002.
`International Preliminaiy Examination Report for International
`(PCT) Patent Application No. PCTUS01/00418. completed Mar. 9,
`2002.
`PCT International Search Report dated Oct. 9, 2002 for PCTHJS01/
`41653.
`Examiner’s First Report for Australian Patent Application No.
`27669/01, mailed Apr. 2, 2004.
`Notice of Acceptance for Australian Patent Application No. 27669/
`01, mailed Aug. 6, 2004.
`Examiner’s First Report for Australian Patent Application No.
`2004203321. mailed Nov. 16. 2006.
`Examiner’s First Report for Australian Patent Application No.
`2008203520, mailed Mar. 9, 2009.
`Notice of Acceptance for Australian Patent Application No.
`2008203520. mailed Jul. 9, 2009.
`Oflicial Action for Canadian Patent Application No. 2.394.491.
`mailed Nov. 24, 2009.
`Official Action for European Patent Application No. 01901808.4,
`mailed Dec. 1, 2004.
`Oflicial Action for European Patent Application No. 019018084,
`mailed Sep. 14, 2005.
`Coirnnunication about intention to grant a European patent for Euro-
`pean Patent Application No. 01901808,4, mailed May 15, 2006.
`European Search Report for European Patent Application No. EP
`06022008 completed Jan. 8, 2007.
`Notification of Reasons (including translation) for Refusal for Japa-
`nese Patent Application No. 2001-552611. Dispatched Date: Dec. 7.
`2009.
`Decision to Grant Patent (including translation) for Korean Patent
`Application No. 10-2002-7008794, dated Dec. 1, 2006.
`Oflicial Action for European Patent Application No EP 06022008,
`mailed Jul. 7. 2010.
`Oflicial Action for Japanese Patent Application No. 2001-552611.
`mailed Aug. 2,2010.
`Official Action for Japanese Patent Application No. 2008—191051,
`mailed Jul. 26, 2010.
`ITU-T g.992.1 “Asymmetric Digital Subscriber Line (ADSL) Trans-
`ceivers” Jun. 1999. p. 91-117. 125. 126. 131, 132.
`
`* cited by exarniner
`
`Page 2 of 9
`
`Page 2 of 9
`
`

`
`U.S. Patent
`
`2
`
`U
`
`2B034,53
`
`comoom
`
`
`
`
`
`_mC__.:._®._.2oEm.m\?0.050_m.:_._®O
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`
`
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`
`Page 3 of 9
`
`Page 3 of 9
`
`
`

`
`U.S. Patent
`
`Nov. 16, 2010
`
`Sheet 2 of2
`
`US 7,835,430 B2
`
`sS100
`
`Commence
`
`Initialization \x
`81 10
`
`Yes
`
`Fig. 2
`
`Diagnostic
`Mode
`?
`
`
`
`
`Transmit Initiate Diagnostic
`Mode Message
`
`Yes
`
`
`
`Re—transmit
`?
`
`
`
`For Predetermined Number Of
`
`Iterations
`
`8220
`5/
`Transmit Diagnostic Link
`Message With CRC
`
`
`
`Increase
`Transmission
`Power
`
`
`Yes
`
`Page 4 of 9
`
`
`
`S140
`
`/V
`Enter Normal
`
`Steady State
`Data
`Transmission
`
`S150
`
`
`
`
`
`Error
`Threshold
`Exceeded
`?
`
`
`
`Page 4 of 9
`
`

`
`US 7,835,430 B2
`
`1
`MULTICARRIER MODULATION
`NIESSAGING FOR FREQUENCY DOMAIN
`RECEIVED IDLE CHANNEL NOISE
`IN FORMATION
`
`FIELD OF THE INVENTION
`
`This invention relates to test and diagnostic information. In
`particular,
`this invention relates to a robust system and
`method for communicating diagnostic information.
`BACKGROUND OF THE INVENTION
`
`10
`
`The exchange of diagnostic and test information between
`transceivers in a telecommtmications 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 example, where the data rate is
`low, where there are many bit errors, or the like, it is necessary
`to collect diagnostic and test information from the remote
`transceiver. This is perfonned by dispatching a technician to
`the remote site, e.g., a truck roll, which is time consuming and
`expensive.
`In DSL teclmology, communications over a local sub-
`scriber loop between a central office and a subscriber pre-
`mises is accomplished by modulating the data to be trans1nit-
`ted onto a multiplicity of discrete frequency carriers which
`are stmimed together and then transmitted over the subscriber
`loop. Individually, the carriers form discrete, non-overlap-
`ping communication subchannels oflimited bandwidth. Col-
`lectively, the carriers form what is effectively a broadband
`communications channel. At the receiver end, the carriers are
`demodulated and the data recovered.
`DSI, systems experience disturbances from other data ser-
`vices on adjacent phone lines, such as, for example, ADSL,
`HDSL, ISDN, T1, or the like. 'lhese disturbances may coin-
`mence after the subj ectADSL service is already initiated and,
`since DSL for internet access is envisioned as an always-on
`service. the effect of these disturbances must be ameliorated
`by the subject ADSL transceiver.
`
`20
`
`mu:
`
`30
`
`o: v:
`
`40
`
`SUMMARY OF THE INVENTION
`
`The systems and methods of this invention are directed
`toward reliably exchanging diagnostic and test information
`between transceivers over a digital subscriber li11e in the
`presence ofvoice commuincations and/or other disturbances.
`For simplicity of reference, the systems and methods of the
`invention will hereafter refer to the transceivers generically as
`modems. One such modem is typically located at a customer ,
`premises such as a home or business and is “downstream”
`from a central ofiice with which it communicates. The other
`modem is typically located at
`the central oflice and is
`“upstream” from the customer premises. Consistent with
`industry practice, the modems are often referred to as “ATU— ,
`R” (“ADSL transceiver unit, remote,” i.e., located at the cus-
`tomer premises) and “AfU —C” (“AD SL transceiver unit, cen-
`tral oflice” i.e., located at the central oflice). jach 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 multi-
`plicity of subchannels of limited bandwidth. "ypically, the
`up stream orATU-C modem transmits data to the downstream
`or ATU-R modem over a first set of subchannels, which are
`usually the higher-frequency subchaimels, and receives data
`from the downstream or ATI I—R modem over a second, usu-
`ally smaller, set of subchannels, commonly the lower—fre—
`
`60
`
`2
`quency subchannels. By establishing a diagnostic link mode
`between the two modems, the systems and methods of this
`invention are able to exchange diagnostic and test infonna—
`tion in a simple and robust marmer.
`In the diagnostic link mode, the diagnostic and test infor-
`mation 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 establish an acceptable con-
`nection iii their normal 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
`and test
`information would normally be
`exchanged, the modems according to the systems and meth-
`ods of this invention enter a robust diagnostic link mode.
`Alternatively, the diagnostic link mode can be entered auto-
`matically or manually, for example, at the direction of a user.
`In the robust diagnostic link mode, the modems exchange the
`diagnostic and test information that is, for example, used by a
`teclmician to determine the cause of a failure without the
`teclmician having to physically visit, ie, a truckroll to, the
`remote site to collect data.
`
`for
`infonnation can include,
`The diagnostic and test
`example, but is not limited to, signal to noise ratio infonna-
`tion, equalizer infomiation, programmable gain setting infor-
`mation, bit allocation information, transmitted and received
`power information, margin information, status and rate infor-
`mation, 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 other known or later developed
`diagnostic or test information that may be appropriate for the
`particular communications enviromnent. For example, the
`exchanged diagnostic a11d test information can be directed
`toward specific limitations of the modems, to infonnation
`relating to the modem installation and deployment environ-
`ment, or to other diagnostic and test information that can, for
`example, be determined as needed which may aid in evaluat-
`ing the cause of a specific failure or problem. Alternatively,
`the diagnostic and test information can include the loop
`length and bridged tap length estimations as discussed in
`copending, filed herewith and incorporated herein by refer-
`ence in its entirety.
`For example, an exemplary embodiment of the invention
`illustrates the use of the diagnostic link mode in the commu-
`nication of diagnostic information from the remote terminal
`(RT) transceiver, e.g., ATU-R, to the central office (CO) trans-
`ceiver, e.g., ATU-C. Transmission of information from the
`remote terminal to the central office is important since a
`typical ADSI, service provider is located in the central otlice
`and would therefore benefit from the ability to determine
`problems at the remote terminal Without a truckroll. However,
`it is to be appreciated, that the systems and the methods ofthis
`invention will work equally well in communications from the
`central office to the remote terminal.
`These and other features and advantages of this invention
`are described in or are apparent from the following detailed
`description of the embodiments.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The embodiments of the invention will be described in
`detail, with reference to the following figures wherein:
`FIG. 1 is a functional block diagram illustrating an exem-
`plary communications system according to this invention;
`and
`
`Page 5 of 9
`
`Page 5 of 9
`
`

`
`US 7,835,430 B2
`
`3
`FIG. 2 is a flowchart outlining an exemplary method for
`communicating diagnostic and test information according to
`tl1is invention.
`
`DETAILED DESCRIPTION OF THE INVENTION
`
`10
`
`TABLE 1
`
`Exemplary‘ Message Variables
`Data Sent in Llie Diag Link
`Train Type
`ADSL Standard
`Chip Type
`Vendor ID
`Code Version
`Average Reverb Received Signal
`Programmable gain amplifier (PGA) Gain — Training
`
`60
`
`For ease of illustration the following description will be
`described i11 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 1noden1 initializationbefore entering into the diag-
`nostic link mode. The systems and methods of this invention
`can enter the diagnostic link mode manually, for example, at
`the direction of a technician or a user after completing a
`portion of initialization. Alternatively, the systems and rnetl1—
`ods of this invention ca11 enter the diagnostic link mode auto-
`matically based on, for example, a bit rate failure, a forward
`error correction or a CRC error during showtime, e.g., the
`normal steady state transmission mode, or the like. The tran-
`sition into the diagnostic link mode is accomplished by trans-
`mitting a message from the CO modem to tl1e 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 rnoder11 indicating
`that the modems are to enter into the diagnostic link mode as
`opposed to transitioning into the nonnal steady state data
`transmission mode. For example, the transition signal uses an
`ADSL state transition to transition from a standard ADSL
`state to a diagnostic link n1ode state.
`In the diagnostic link mode, the RT modem sends diagnos-
`tic and test information in the form of a collection of infor-
`mation bits to the CO modem that are, for example, modu-
`lated by using one bit per DTM symbol modulation, as is used
`in the C -Ratesl message in the ITU and ANSI ADSL stan-
`dards, where the symbol may or may not include a cyclic
`prefix. Other exemplary modulation techniques include Dif-
`ferential Phase Shift Keying (DPSK) on a subset or all the
`carriers, as specilied in, for example, ITU standard G.994.l,
`higher order QAM modulation (>1 bit per carrier), or the like.
`In T16 one bit per DMT symbol modulation message
`encoding scheme, a bit with value 0 is mapped to the
`REVE {Bl signal and a bit with a value of mapped to a
`SAGUAI signal. The REVERBI and SAGUAI signals are
`defined in the ITU and ANSI ADSL standards. The
`REVE {Bl signal is genera ed by modulating all of the car-
`riers in the inulticarrier system with a known pseudo-ra11don1
`sequence thus generating a wideband modulated signal. The
`S ‘GU
`ll signal is generated from a carrier by 180 degree -
`phase reversal ofthe REVERBI signal. Since both signals are
`wideband and known in advance, the receiver can easily
`detect the REVERBI and SAGUAI signal using a simple
`matched filter in the presence of large amounts of 11oise and
`other disturbances.
`
`20
`
`mu:
`
`30
`
`U1 V:
`
`40
`
`4
`
`TABLE l-continued
`
`Exemplary Message Variables
`’ragrammable gain amplifier PGA Gain - Showtime
`:ilter Present during Idle Channel Calculation
`Average Idle Cliannel Noise
`Signal to Noise during Training
`Signal to Noise during Showtime
`its and Gains
`Data Rate
`Framing Mode
`Margin
`{ccd-Solomon Coding Gain
`QA.\/I Usage
`:requency Domain Equalizer (FDQ) Coefficients
`Gain Scale
`Time domain equalizer (TDQ) Coefficients
`)igital Echo Canceller (DEC) Coefficients
`
`Table 1 shows a11 example of a data message that can be
`sent by he RT to the CO during the diagnostic link mode. In
`this example, the RT modem sends 23 different data variables
`to the CO. Each data variable contains different items of
`diagnos ic and test information that are used to analyze the
`condition of the link. The variables may contain more than
`one item of data. For example, the Average Reverb Signal
`contains the power levels per tone, up to, for example, 256
`entries, detected during the ADSL Reverb signal. Conversely,
`the PGA Gain—'l'raining is a single entry, denoting the gain ir1
`dB at the receiver during the ADSL training.
`Many variables that represent the type of diagnostic and
`test information that are used to analyze the condition of the
`link are sent from the RT modem to the CO modem. These
`variables ca11 be, for example, arrays with different lengths
`depending on, for example, information in the initiate diag-
`nostic mode message. The systems and methods ofthis inven-
`tion can be tailored to contain many different diagnostic and
`test information variables. Thus, the system is fully config-
`urable, allowing subsets ofdata to be sent and additional data
`variables to be added in the future. Therefore, the message
`length can be increased or decreased, and diagnostic and test
`information customized, to support more or less variables as,
`for example, hardware, the environment ar1d/or the telecom-
`munications equipment dictates.
`Therefore, it is to be appreciated, that ir1 general the Vari-
`ables transmitted from the rnoder11 being tested to the receiv-
`ing n1oden1 can be any combination of variables which allow
`for transmission of test and/or diagnostic infomiation.
`FIG. 1 illustrates an exemplary embodiment of the addi-
`tional modem components associated with the diagnostic link
`mode. Inparticular, the diagnostic link system 100 comprises
`a central oflice modem 200 and a remote terminal modem
`300. The central ofl"1ce modem 200 comprises, in addition to
`the standard ATU-C components, a CRC checker 210, a diag-
`nostic device 220, and a diagnostic information monitoring
`device 230. The remote terminal modem 300 comprises, in
`addition to the standard components associated with an ATU-
`R, a message determination device 310, a power control
`device 320, a diagnostic device 330 and a diagnostic ii1for—
`mation storage device 340. The central olfice mode111 200 and
`the remote tenninal 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.lite) or with an in-line filter in series with the phone 40. In
`addition, the remote terminal modem 300, can also be con-
`nected to, for example, one or more user terminals 60. Addi-
`tionally, the central otlice modem 200 can be connected to
`
`Page 6 of 9
`
`Page 6 of 9
`
`

`
`US 7,835,430 B2
`
`5
`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. 1
`shows the diagnostic Iii1k system 100 for an e1nbodin1e11t in
`which the remote ten11i11al modem 3 00 is communicating test
`and diagnostic information to the central office 200, it is to be
`appreciated that the various components ofthe diagnostic link
`system can be rearranged such that the diagnostic and test
`information can be forwarded from the central office 200 to
`the remote terminal modem 300, or, alternatively, such that
`both modems can send and receive diagnostic and/or test
`information. Furthermore,
`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 telecoimnunications
`network. Tl1us, it should be appreciated that the components
`of the diagnostic link system 100 can be combined into one
`device for respectively transmitting, receiving, or transmit-
`ting and receiving diagnostic and/or test information. As will
`be appreciated from the following description, and for rea-
`sons ofcomputational efficiency, the components ofthe diag-
`nostic link system 100 can be arranged at any location within
`a telecommunications network a11d/or modem without allect—
`ing the operation of the system.
`The links 5 can be a wired or wireless link or any other
`known or later developed eIement(s) that is capable of sup-
`plying and conmiunicating electronic data to and from the
`connected elements. Additionally. the user terminal 60 can
`be, for example, a personal computer or other device allowing
`a user to interface with and communicate over a modem, such
`as a DSL modem. Furthermore, the systems and method of
`this invention will work equally well with splitterless and
`low—pass multicarrier modern technologies.
`In operation, the remote terminal 300, commences its nor-
`mal initialization sequence. 'I'he diagnostic device 330 n1oi1i—
`tors the initialization sequence for a failure. If there is a
`failure, the diagnostic device 330 initiates the diagnostic link
`mode. Alternatively, a user or. for example, a technician at the
`CO, can specify that the remote terminal 300 enter into the
`diagnostic link mode after completing a portion of a11 initial-
`ization. Alternatively still, the diagnostic device 330 can
`monitor the normal steady state data transmission of the
`remote tenninal, 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 diag-
`nostic device 330, in cooperation with the remote terminal
`300 will transmit an initiate diagnostic link mode message
`from the remote terminal to the central office 200 (RT to CO).
`Alternatively, the central office modem 200 can transmit an
`initiate diagnostic link mode mes sage to the remote terminal
`modem 300. If the initiate diagnostic link mode message is
`received by the central ofl"1ce 200, the diagnostic device 330,
`in cooperation with the message determination device 310,
`determines a diagnostic link message to be forwarded to the
`central ollice 200. For example, the diagnostic link message
`can include test information that has been assembled during,
`for example, the i1onnalADSL initialization procedure. The
`diagnostic a11d/or test information ca11 include, but is not
`limited to, the version number ofthe diagno stic link mode, the
`length of the diagnostic and’or test inormation, the commu-
`nications standard, such as the 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,
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`the signal to noise ratio, the bits and gains and the upstream
`and downstream transmission rates, or the like.
`Ifthe initiate diagnostic link mode message is not received
`by the central office 200, the initiate diagnostic link mode
`message can, for example, be re-transmitted a predetermined
`number ofiterations until a determination is made that it is not
`possible to establish a connection.
`Assuming the initiate diagnostic link n1ode message is
`received, then. for a predetennined number of iterations, the
`diagnostic device 330, in cooperation with the remote tenni-
`nal modem 300 and the diagnostic information storage device
`340, transmits the diagnostic link message with a cyclic
`redundancy check (CRC) to the central office modern 200.
`However, it is to be appreciated that in general, any error
`detection scheme, such as bit error detection, can be used
`without allecting the operation of the system. The central
`office 200, in cooperation with the CRC checker 210, deter-
`mines if the CRC is correct. If the CRC is correct, the diag-
`nostic information stored in the diagnostic information stor-
`age device 340 has been, with the cooperation of the
`diagnostic device 330, and the remote tenninal modem 300,
`forwarded to the central office 200 successfully.
`If, for example, the CRC checker 210 is unable to deter-
`mine the correct CRC, the diagnostic device 330, in coopera-
`tion with power control device 320, increases the trai1sinis—
`sion power of the remote terminal 300 and repeats the
`transmission of the diagnostic li11k mes sage from the remote
`tenninal 300 to the central office 200. This process continues
`until the correct CRC is determined by the CRC checker 210.
`The maximum power level used for transmission of the
`diagnostic link message can be specified by, for example, the
`user or the ADSL service operator. If the CRC checker 210
`does not determine a correct CRC at the maximum power
`level and the diagnostic link n1ode can not be initiated then
`other methods for detennining diagnostic information are
`utilized, such as dispatching a teclmician to the remote site. or
`the like.
`
`Altematively, the remote terminal 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 mes sage several times, the CO modem 200
`can use, for example, a diversity combining scheme to
`improve the probability of obtaining a correct CRC from the
`received diagnostic link 1nessage(s).
`Altematively, as previously discussed, the central office
`200 comprises a diagnostic information monitoring device
`230. The remote terminal 300 can also include a diagnostic
`information monitoring device. One or more of these diag-
`nostic information monitoring devices can monitor the nor-
`mal steady state data transmission between the remote tem1i-
`nal 300 and the central office 200. Upon, for example, the
`normal steady state data transmission exceeded a predeter-
`mined error threshold, the diagnostic information monitoring
`device can initiate the diagnostic link mode with the coopera-
`tion ofthe diagnostic device 300 and.’or the diagnostic device
`220.
`
`FIG. 2 illustrates an exemplary method for entering a diag-
`nostic link 111ode in accordance with this invention. In par-
`ticular, control begins in step S100 and continues to step
`S11 0. In step S1 10, the initialization sequence is commenced.
`Next, in step S120, if an initialization failure is detected,
`control continues to step S170. Otherwise, control jumps to
`step S130. In step $130, a determination is made whether the
`diagnostic link mode has been selected. If the diagnostic link
`mode has been selected, control continues to step S170, oth-
`erwise, control jumps to step S140.
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`US 7,835,430 B2
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`In step S170, the initiate diagnostic link mode message is
`transmitted from, for example, the remote terminal
`to the
`central ollice. Next, in step S180, a determination is made
`whether the initiate diagnostic mode message has been
`received by the CO. If the initiate diagnostic mode message
`has been received by the CO, control jumps to step S200.
`Otherwise, control continues to step S190. In step S190, a
`determination is made whether to re-transmit the initiate
`diagnostic mode message, for example, based on whether a
`predetermined munber of iterations have already been coin-
`pleted. If the initiate diagnostic mode message is to be rc-
`transmitted, control continues back to step S170. Otherwise,
`control jumps to step S160.
`In step S200, the diagnostic link message is determined, for
`example, by assembling test and diagnostic information
`about one or more of the local loop, the modem itself, the
`telephone network at the remote terminal, or the like. Next, in
`step S210, for a predetermined number of iterations, steps
`S220-S240 are completed. hi particular, in step S220 a diag-
`nostic lii1k message comprising a CRC is transmitted to, for
`example, the CO. Next, in step S230, the CRC is determined.
`Then, in step S240, a determination is made whether the CRC
`is correct. If the CRC is correct, the test andjor diagnostic
`information has been successfully communicated and control
`continues to step S160.
`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 con-
`tinues back to step S210. Alternatively, as previously dis-
`cussed, the diagnostic lii1k message may be transmitted a
`predetermined number oftimes, with our without a change in
`the transmission power.
`In step S140, the normal steady state data transmission is
`entered into between two modems, such as the remote termi-
`nal aiid the central ollice modems. Next, in step S150, a
`determination is made whether an error threshold during the
`normal steady state data transmission has been exceeded. If
`the error threshold has been exceeded, control continues to
`step S170. Otherwise, control jumps to step S160. hi step
`S160, the control sequence ends.
`As shown in FIG. 1. the diagnostic link mode system 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 can also be
`implemented on a special purpose computer, a programmed
`microprocessor or microcontroller and peripheral integrated
`circuit element, an 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
`commtuiications equipment. hi 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 inven— ,
`tion.
`Furthermore, the disclosed method may be readily imple-
`mented in software using object or object—oriented software
`developmentenvironments that provide portable source code
`that can be used on a variety of computer, workstation, or
`modem hardware platforms. Alternatively,
`the disclosed
`diagnostic link system may be implemented 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 invention depending on the
`sp