(12)
`
`United States Patent
`Cheng et al.
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 7,031,380 B1
`Apr. 18, 2006
`
`US007031380B1
`
`(54) MULTI-CLIENT ADSL MODEM
`
`6,279,022 B1* 8/2001 Miao et al. ................. 708.404
`6,295,293 B1* 9/2001 Tonnby et al. .
`... 370,389
`6,351,487 B1 ck
`2/2002 Lu et al. ........
`... 375,225
`6,389,062 B1* 5/2002 Wu ........
`... 375.222
`6.424,661 B1* 7/2002 Bentley ..
`... 370,482
`6,430,199 B1* 8/2002 Kerpez ......
`... 370,493
`6,434,119 B1* 8/2002 Wiese et al. ................ 370,252
`(Continued)
`FOREIGN PATENT DOCUMENTS
`WO 98 20649. A
`5, 1998
`WO
`Primary Examiner Emmanuel Bayard
`Assistant Examiner—Lawrence B. Williams
`(74) Attorney, Agent, or Firm Abdul Zindani; W. James
`Brady, III; Frederick J. Telecky, J
`rady, Ill, Freder1CK J. TeleCKy, Jr.
`
`ABSTRACT
`(57)
`A multi-client ADSL modem network (10) that can be
`configured for a home or office network when multiple
`ADSL client modems (18) are installed in different commu
`nication terminals (22). One ADSL modem (14) at a central
`office (12) coordinates the remote multi-client modems (18)
`for communication over a single twisted pair loop carrier
`phone line (16), allowing the connected modems (18) to
`communicate not only with the CO modem (14), but also
`with each other by sharing frames, tones, or by code division
`techniques on upstream channels. The CO modem (14)
`operates as a network hub and/or arbitrator, and facilitates
`one ADSL modem to become the master modem and main
`tain a Superframe. The present invention provides home
`network ADSL service without extra wiring or equipment,
`thus providing a low cost approach for home networking of
`ADSL Service.
`
`22 Claims, 3 Drawing Sheets
`
`(75) Inventors: Yaqi Cheng, Smyrna, GA (US); Yaser
`M. Ibrahim, Richardson, TX (US);
`s
`s
`s
`Song Wu, Plano, TX (US)
`(73) Assignee: Texas Instruments Incorporated,
`Dallas, TX (US)
`Subject to any disclaimer, the term of this
`past iss, so listed under 35
`
`(*) Notice:
`
`M
`
`YW-
`
`y
`
`ayS.
`
`(21) Appl. No.: 09/651,976
`
`22) Filed
`1C
`
`Aug. 31, 2000
`l. 3,
`
`Related U.S. Application Data
`(60) EYal application No. 60/156.484, filed on Sep.
`s
`(51) Int. Cl
`itoul iA38
`H04L 2/56
`375/222; 370/352
`52) U.S. C
`.
`Fi id ic- - - - - - ficati - - - - - -s - - - - - - - h.
`375,222.
`(58) Field of Classification Search ................
`s
`370/293–389, 468,408,480, 489, 498, 352,
`37Of 421
`See application file for complete search history.
`References Cited
`
`(2006.01)
`(2006.015
`
`(56)
`
`U.S. PATENT DOCUMENTS
`
`5,479,447 A 12, 1995 Chow et al. ................ 375,260
`5,812,786 A * 9/1998 SeaZholtz et al. ........... TO9,233
`5,896,443 A * 4, 1999 Dichter .................... 379,93.08
`5,933,454. A * 8/1999 Cioff ......................... 375,260
`
`62
`
`SINGLE MODEM
`STATE
`
`ENTERNG STATE
`
`60 y
`
`
`
`
`
`
`
`
`
`64
`
`SECOND MODEM
`REQUEST
`
`ONE MORE MODEM REOUESTS FOR MULTI-CLIENT
`ADSL OPERATION BY SIGNALING CO
`
`CURRENT
`MODEMS
`RE-MITALIZE
`
`COMOOEM INFORMS THE FIRST RT MODEM
`TO BE THE MASTER OF MULTI-CLIENT
`OPERATION AND DROP SOME FRAMES
`
`NEW MODEMS
`INITIALIZE
`
`INTIALIZE THE SECOND MODEM TO SHARE THE
`DROPPED FRAMES. NON-MASTER CLIENT MODEM
`DOES NOT GENERATE THE SYNC FRAME WHCH
`S BY THE MASTER CLIENT MODEM ONLY
`
`CHECK THE SETUP IF READY
`
`MULTI-CIENT
`MODEM STATE
`
`72
`
`WHEN SETUP READY. THE SYSTEM ENTERS
`MULTI-CLIENT MODEM STATE, ONE CO MODEM
`TALKS TO MULTIPY RT CLIENT MODEM
`THROUGH ONE PAIR PHONE LINE
`
`Comcast, Ex. 1042
`
`1
`
`

`

`US 7,031,380 B1
`Page 2
`
`U.S. PATENT DOCUMENTS
`
`8/2002 Park ........................... 370,293
`6,434,123 B1
`6.459,684 B1 * 10, 2002 Conroy et al. .............. 370,286
`6,473.438 B1 * 10/2002 Ciofi et al. ................ 370/468
`6,480.475 B1* 11/2002 Modlin et al. .
`... 370,294
`6,498,807 B1 * 12/2002 Hwang ....................... 375.222
`6,501,791 B1* 12/2002 Hwang ....................... 375.222
`
`12, 2002 Davis - - - - - - - - - - - - - - - - - - - - - - - - - 375.222
`
`6,498,806 B1 ck
`
`6,584,079 B1* 6/2003 Willer ........................ 370,284
`6,590,893 B1* 7/2003 Hwang et al.
`370,354
`6,603,808 B1* 8/2003 Anne et al. ................. 375.222
`6,636,505 B1 * 10, 2003 Wang et al. ................ 370,352
`6,704,317 B1 * 3/2004 Dobson ...
`370/401
`2001/0012319 A1* 8/2001 Foley ......................... 375.222
`
`
`
`2002/0136167 A1 ck
`
`9, 2002 Steele et al. - - - - - - - - - - - - - - - - 370,260
`
`* cited by examiner
`
`2
`
`

`

`U.S. Patent
`
`Apr. 18, 2006
`
`Sheet 1 of 3
`
`US 7,031,380 B1
`
`12
`
`FIC.
`
`f
`
`26
`
`10
`
`CENTRAL OFFICE
`
`
`
`) REMOTE TERMINAL(S
`
`
`
`
`
`
`
`wa-a-ayy-ass=7 FREQUENCY
`
`MODEMS BY
`SHARING TONES
`
`FIG. 3A
`
`MODEM 1 TAKES FRAME in
`MODEM 2 TAKES FRAME n2
`MODEM 3 TAKES FRAME in
`
`-----------------------------
`
`Y=v-yv-wi-y FREQUENCY
`
`3
`
`

`

`U.S. Patent
`
`Apr. 18, 2006
`
`Sheet 2 of 3
`
`US 7,031,380 B1
`
`Co
`v
`
`07
`
`07
`
`99,
`
`"13S ENOHdBT3||
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`80 "W3C]OW ONWEBOIOA
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`s
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`4
`
`

`

`U.S. Patent
`
`Apr. 18, 2006
`
`Sheet 3 of 3
`
`US 7,031,380 B1
`
`FIC 4
`
`
`
`
`
`62
`
`SINGLE MODEM
`STATE
`
`ENTERING STATE
`
`5
`
`
`
`
`
`SECOND MODEM
`REQUEST
`
`ONE MORE MODEM REQUESTS FOR MULTI-CLIENT
`ADSL OPERATION BY SIGNALING CO
`
`CURRENT
`MODEMS
`RE-NITIALIZE
`
`CO MODEM INFORMS THE FIRST RT MODEM
`TO BE THE MASTER OF MULTI-CLIENT
`OPERATION AND DROP SOME FRAMES
`
`NEW MODEMS
`NITIALIZE
`
`INITIALIZE THE SECOND MODEM TO SHARE THE
`DROPPED FRAMES.. NON-MASTER CLIENT MODEM
`DOES NOT GENERATE THE SYNC FRAME WHICH
`S BY THE MASTER CLIENT MODEM ONLY
`
`CHECK THE SETUP IF READY
`
`72
`
`MULTI-CIENT
`MODEM STATE
`
`WHEN SETUP READY, THE SYSTEM ENTERS
`MULTI-CLIENT MODEM STATE, ONE CO MODEM
`TALKS TO MULTIPLY RT CLIENT MODEM
`THROUGH ONE PAIR PHONE LINE
`
`5
`
`

`

`US 7,031,380 B1
`
`1.
`MULTI-CLIENT ADSL MODEMI
`
`PRIORITY
`
`This application claims priority under 35 USC S 119(e)(1)
`of Provisional Application No. 60/156.484, filed Sep. 28,
`1999.
`
`FIELD OF THE INVENTION
`
`The present invention is generally related to communica
`tion networks, and more specifically to networks adapted to
`communicate over standard residential 2-wire phone lines
`including those adapted to Support ADSL communications.
`
`BACKGROUND OF THE INVENTION
`
`10
`
`15
`
`25
`
`30
`
`35
`
`45
`
`Asymmetrical Digital Subscriber Lines (ADSL) is an
`ANSI Standard identified as TI.413 issued in 1995 which
`presents the electrical characteristics of the ADSL signal as
`it should appear at a network interface. Generally, ADSL is
`a high-speed communication technology that allows one
`client modem, such as that at a remote terminal (RT), to be
`connected to only one central office (CO) modem through
`one twisted pair telephone line forming a loop. Typically,
`discrete multi-tone (DMT) modulation is the chosen line
`code technique standard in a typical ADSL system.
`Upstream communications, such as from RT to CO, and
`downstream communications, such as CO to RT, are divided
`from one another using frequency division multiplexing
`(FDM) or using echo canceling, allowing the frequency
`band for upstream communications to be shared with down
`stream communications thereby increasing the overall data
`rate over the loop.
`Disadvantageously, the ADSL standard allows only one
`pair of modems (CO and RT) to communicate over a loop at
`the same time. The CO modem may send a downstream
`signal while simultaneously receiving an upstream signal
`from the RT, frame by frame. Similarly, the RT modem may
`receive the downstream communication from the CO
`40
`modem and simultaneously send upstream communication
`signals to the CO modem.
`Since the standardization of ADSL communications, there
`have been introduced varied implementations and custom
`ized uses of the ADSL technology, such as disclosed in
`commonly assigned U.S. Pat. No. 5,479,447 entitled
`“Method and Apparatus for Adaptive, Variable Bandwidth,
`High-Speed Data Transmission of a Multi-Carrier Signal
`over Digital Subscriber Lines, the teachings of this patent
`included herein by reference.
`As homes and offices become more networked, there are
`typically multiple communication terminals and devices in
`the residential house or office, and local networks are likely
`installed to share resources. Such as internet access, printers,
`and so on. Home networks are particularly unique in that
`cost and wiring issues are key considerations. The IEEE
`1394 standard has been recently developed which provides
`for data speeds up to hundreds Mbps. However, the IEEE
`1394 standard also requires special cabling for connection,
`and is not adapted to operate over the common twisted pair
`telephone lines wired typically throughout a home, for
`example. A new consortium of home networking, known as
`Home Phoneline Networking Alliance (HomePNA), was
`formed. HomePNA is able to connect PCs and peripherals
`within a household through a single pair phone line shared
`not only with the telephone sets, but also with xDSL services
`provided by modems exchanging information over the con
`
`50
`
`55
`
`60
`
`65
`
`2
`ventional twisted pair phone lines. HomePNA runs at the
`frequency range from 5.5 MHz to 9.5 MHz, while the Plain
`Old Telephone Service (POTS) operates in the frequency
`range under 4 KHZ, and the xDSL service operates at the
`frequency range from 275 KHZ to 1 MHz. The current
`available HomePNA technology can provide 1 Mbps Eth
`ernet local networking, and may reach 10 Mbps in the near
`future.
`
`SUMMARY OF THE INVENTION
`
`The present invention achieves technical advantages as a
`Multi-Client ADSL Modem and network that can be con
`figured as a home network by providing multiple ADSL
`modems installed in different communication terminals
`which may be connected to and coordinated by a multi
`client modem at a central office serving as a network hub.
`This architecture allows connected PCs, for instance, to
`share internet access, printers, file storage, and so forth, but
`without extra hardware cost like Ethernet cards or upgraded
`cables. Each connection terminal, such as a PC, is able to
`communicate with the other as a home network by commu
`nicating over a single pair of twisted phone line conductors
`with the central office modem serving as a network hub. The
`present invention provides three sharing schemes allowing
`the multi-client ADSL modems to communicate with the
`central office, and to communicate with each other through
`the standard phone line connection. The sharing schemes
`include frame multiplexing, tone sharing, and code division.
`In the frame multiplexing architecture, all connected
`multi-client ADSL modems receive the same downstream
`signal from the CO modem. Each multi-client ADSL modem
`takes the data package addressed to it from the downstream
`signal. Each multi-client ADSL modem is allowed in sched
`ule to send one or more frames to the CO modem, while the
`other multi-client ADSL modems keep quiet. This CO
`modem can return the frame data from one multi-client
`ADSL modem to another multi-client ADSL modem
`through downstream channels. One of the multi-client
`ADSL modems is first connected to the CO modem, and is
`then configured as the master multi-client ADSL modem.
`Using the tone sharing technique, all connected multi
`client ADSL modems receive the same downstream signals
`from the CO modem. Each multi-client ADSL modem takes
`the data package itself asked, whereby each multi-client
`ADSL modem uses a number of upstream tones to the CO
`modem while other multi-client ADSL modems use different
`tones, and which tones can be sent simultaneously. The CO
`modem can return the data from one multi-client ADSL
`modem to another multi-client ADSL modem through
`downstream channels. One of the multi-client ADSL
`modems is first connected to the CO modem, and is then
`configured as the master multi-client ADSL modem. The
`master multi-client ADSL modem will maintain the super
`frame transmission if other multi-client ADSL modems join
`in, one after another.
`Using the code division architecture, all connected multi
`client ADSL modems receive the same downstream signal
`from the CO modem. Each multi-client ADSL modem takes
`the data package itself asked. Each multi-client ADSL
`modem is set up to code its data with a special signed key
`word, such as is used in CDMA wireless applications. The
`ADSL modem then modulates the coded data in all frames
`and in all tones. The CO modem can decode the data and
`re-send the data back to other multi-client ADSL modems
`through downstream channels.
`
`6
`
`

`

`US 7,031,380 B1
`
`3
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a block diagram configuration of two multi
`client ADSL modems located within a single residence and
`each communicating over a single twisted pair phone line to
`a remote single CO modem for communication with one
`another, or for communication between either RT modem
`and the CO modems;
`FIG. 2 is a block diagram of a multi-client ADSL system,
`whereby multi-client ADSL modems each communicate
`with the central office (CO) modem through one loop carrier
`comprising a single pair of twisted conductors;
`FIG. 3A and FIG. 3B are graphs depicting how the
`multi-client modems share one upstream channel by frame
`multiplexing and tone division; and
`FIG. 4 illustrates a method of initializing the multi-client
`ADSL modems with one becoming the master modem
`maintaining the Superframe.
`
`10
`
`15
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENT
`
`4
`network. The Voice band communications provide regular
`Plain Old Telephone Service (POTS) or ISDN telephony
`service.
`The multi-client ADSL system 10 allows each of the
`multiple client modems 18 to operate on the same single pair
`of twisted conductor phone line routed through a home or
`office to communicate with and through a single CO modem
`14, simultaneously. No additional equipment or special
`wiring is needed. Rather, the internal phone line throughout
`the home is used. With the multi-client ADSL system 10, the
`remote communication terminals, which are depicted as a
`customer premise network 40 in FIG. 2, can be locally
`networked without additional hardware cards, or special
`wiring such as CAT-5 wiring. The PCs 22 at the residential
`site 26 can access the internet through the network 10 via the
`resources at the CO 12, but can also communicate with each
`other as a local office network or a home network.
`Referring now to FIG. 3A and FIG. 3B, the multi-client
`modems 18 Serving the respective remote terminals 22 can
`be adapted to share the upstream communications by send
`ing data from the RT modem 18 to the CO modem 14 using
`frequency division (sharing tones), by time division (sharing
`frames), or even applying code division like signatures
`similar to CDMA in wireless communications.
`In frequency division, as shown in FIG. 3A, each multi
`client modem 18 is assigned unique tones for use on
`upstream channels. In time division, as shown in FIG. 3B.
`each multi-client modem 18 utilizes some frames on the
`upstream channels while the other modems are keeping
`quiet. Alternatively, code division allows the multi-client
`modems 18 to send data on upstream channels simulta
`neously to the CO modem 14, covering all frames and all
`tOneS.
`On downstream channels, each multi-client modem 18
`receives all the data packets from CO modem 14, but is also
`adapted to ascertain the data packets that it has requested. A
`data packet has certain information bits that shows its
`destination, and which information bits such as header bits
`are used by each RT modem 18 to identify and decipher the
`associated data therewith to determine if the data is to be
`interpreted. One of the multi-client ADSL modems 18 is first
`connected to the CO modem 14 and is responsively config
`ured by the CO modem 14 as the master multi-client ADSL
`modem 18. This identified master multi-client ADSL
`modem 18 then maintains a Superframe transmission if other
`multi-client ADSL modems 18 join in, one after another.
`This superframe is not shared by other multi-client ADSL
`modems.
`Now referring to FIG. 4, there is illustrated at 60 a
`methodology by which the client modems 18 are initialized
`for use in the multi-client modem network 10, as shown in
`FIG. 1 and FIG. 2. The multi-client ADSL system 10 is
`compliant to the single client ADSL system when only one
`client modem 18 is connected to the loop carrier 16 com
`prising a single phone line.
`The system 10 first enters into the single modem state at
`step 62, similar to a normal ADSL system. Next, at step 64,
`if there is a second modem 18 initialized and turned on, this
`new added modem 18 requests for connection by signaling
`the CO modem 14 with a special handshaking message
`exchange. The CO modem 14 responds to this request by
`informing the first modem 18 to skip transmitting some
`frames in a time division implementation, or some tones in
`a frequency division implementation. The CO modem 14
`then provides for the first modem 18 to be re-trained as
`necessary at step 66. The CO modem 14 informs the first RT
`
`25
`
`30
`
`35
`
`40
`
`Referring now to FIG. 1, there is shown at 10 a multi
`client ADSL network including a central office (CO)12
`having a CO modem 14 connected via a single twisted pair
`loop of telephone conductors 16 to remote terminal (RT)
`modems 18. The CO modem 14 is adapted to serve one or
`more respective communication terminals 20, which may be
`a landline phone, computer, or wireless communication
`device. The respective RT modems 18 are adapted to serve
`respective communication terminals 22 such as PC, wireline
`phone, or wireless communication terminals such as a
`personal digital assistant (PDA). Also shown is a standard
`telephone 24 also connected to and communicating over the
`single loop carrier 16 for providing voice communications
`with remote terminals served by the central office 12. In this
`multi-client modem configuration 10, the RT terminals 22,
`which may be PCs, can not only access internet communi
`cations through the network via resources at the CO 12, but
`can also communicate at a common site 26 with each other
`as a local home network or an office network.
`Referring to FIG. 2, there is depicted in more detail the
`network 10 of FIG. 1 which provides regular ADSL com
`munication service between the residential client modems
`45
`18 depicted as ATU-R, via the single loop carrier 16 and the
`CO modem 14 identified as ATU-C. Both the CO modem 14
`and the RT modems 18 are equipped with frequency splitters
`and network resources 30, each splitter comprising a high
`pass filter 32 and a low pass filter 34. The high pass filter 32
`and the low pass filter 34 each separate the ADSL frequency
`band communications from the Voice frequency band com
`munications. Thus, a telephone set, Voice band modem, or
`ISDN terminal, such as shown at 36, can communicate with
`a narrowband network 38 via a single loop carrier 16, as
`55
`shown. Likewise, the high pass filters 32 facilitate commu
`nication between customer premise networks 40 via loop
`carrier 16 with a broadband network 42.
`Depicted at 44 is the common single twisted pair of
`telephone line extending between the remote terminal
`modems 18, Such as in a daisy chain arrangement from
`outlet to outlet within a home. Each of these RT modems 18
`is connected to and communicates through the respective
`high pass filter 32 of the splitter at the home. The ADSL
`service communicating between customer premise network
`65
`40 and broadband network 42 provides broadband network
`service to each home communication device in the home
`
`50
`
`60
`
`7
`
`

`

`US 7,031,380 B1
`
`10
`
`25
`
`30
`
`35
`
`5
`modem 18 to be the master modem of the multi-client
`operation and drops some frames.
`At step 68, after re-setup of the first modem 18, the CO
`modem 14 will acknowledge and start a training process for
`the second modem whereby the second modem 18 shares the
`dropped frames. The non-master client modem 18 does not
`generate the Sync frame, which is generated by the master
`client modem 18 only.
`At step 70, if the set-up is ready, the system 10 enters the
`multi-client modem state, whereby one CO modem 14
`communicates with the multiple RT client modems 18
`through the single pair of phone line 16 known as loop
`carrier. If at step 70 the set-up of the system is not ready, the
`system returns back to step 66. When two or more client
`modems 18 are joining the single pair phone line 16, the CO
`15
`modem 14 can re-train the first two modems 14, release
`more frames or tones for the newly requesting modem 18,
`then set up the other.
`In Summary, the present invention provides a local home
`or office network by which multiple remote terminals at a
`residential location or office can communicate with one
`another over a single common pair phone line, without
`requiring special equipment or additional wiring. The cen
`tral office modem 14 operates as a network hub, providing
`ADSL service over a single pair of phone line, to route
`communications from one remote terminal to another where
`all the remote terminals may reside within a common
`location. One remote terminal may communicate with the
`other, one at a time, or simultaneously depending on the
`architecture used. The regular telephone service communi
`cating Voiceband signals is not affected. Splitters are used to
`separate the high frequency signals of ADSL from the low
`frequency signals for voice communications. The present
`invention utilizes ADSL communications that conform to
`ADSL standards.
`Though the invention has been described with respect to
`a specific preferred embodiment, many variations and modi
`fications will become apparent to those skilled in the art
`upon reading the present application. It is therefore the
`intention that the appended claims be interpreted as broadly
`as possible in view of the prior art to include all such
`variations and modifications.
`
`40
`
`50
`
`We claim:
`1. A method of communication in a network comprising
`45
`a network node and a plurality of modems coupled to the
`network node by a common master loop, the method com
`prising:
`initiating communication between a first modem and the
`network node:
`initiating communication between a second modem and
`the network node:
`directing the first modem to release a portion of commu
`nication bandwidth used by the first modem;
`using the portion of communication bandwidth released
`by the first modem for the second modem to establish
`simultaneous communication over the common master
`loop between the network node and the first and second
`modems.
`2. The method of claim 1, wherein
`the first modem is configured to communicate with the
`network node as a master terminal while maintaining a
`Superframe of the communication bandwidth.
`3. The method of claim 2, wherein
`the first and second modems are configured to commu
`65
`nicate with the network node using time division mul
`tiplexing; and
`
`55
`
`60
`
`6
`the first modem releases one or more time frames for the
`second modem to communicate in the network.
`4. The method of claim 2, wherein
`the first and second modems are configured to commu
`nicate with the network node using frequency division
`multiplexing; and
`the first modem releases one or more frequency tones for
`the second modem to communicate in the network.
`5. The method of claim 1, wherein the first and second
`modems are configured to communicate with each other via
`the network node over the common master loop.
`6. The method of claim 1, wherein the first and second
`modems are configured to communicate in the network
`using signals compatible with ADSL standards.
`7. The method of claim 1, wherein the common master
`loop comprises a single twisted pair of conductors.
`8. A method of operating a modem in a network, the
`method comprising:
`initializing the modem to communicate with a network
`node via a master loop; and
`upon receiving a signal from the network node, releasing
`a portion of communication bandwidth used by the
`modem for one or more communication terminals
`coupled to the network node via the master loop,
`wherein the modem releases the portion of the com
`munication bandwidth while maintaining a Superframe
`of the communication bandwidth.
`9. The method of claim 8, wherein
`the modem is configured to communicate with the net
`work node using time division multiplexing; and
`the modem releases one or more time frames for the one
`or more communication terminals.
`10. The method of claim 8, wherein
`the modem is configured to communicate with the net
`work node using frequency division multiplexing; and
`the modem releases one or more frequency tones for the
`one or more communication terminals.
`11. The method of claim 8, wherein the modem and the
`one or more communication terminals are configured to
`communicate in the network using signals compatible with
`ADSL standards.
`12. A communication system for communication in a
`network comprising a network node and a plurality of
`modems coupled to the network node by a common master
`loop, the system comprising:
`means for initiating communication between a first
`modem and the network node:
`means for initiating communication between a second
`modem and the network node:
`means for directing the first modem to release a portion of
`communication bandwidth used by the first modem;
`means for using the portion of communication bandwidth
`released by the first modem for the second modem to
`establish simultaneous communication over the com
`mon master loop between the network node and the
`first and second modems.
`13. The system of claim 12, wherein
`the first modem is configured to communicate with the
`network node as a master terminal while maintaining a
`Superframe of the communication bandwidth.
`14. The system of claim 13, wherein
`the first and second modems are configured to commu
`nicate with the network node using time division mul
`tiplexing; and
`the first modem is further configured to release one or
`more time frames for the second modem to communi
`cate in the network.
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`15. The system of claim 13, wherein
`the first and second modems are configured to commu
`nicate with the network node using frequency division
`multiplexing; and the first modem is further configured
`to release one or more frequency tones for the second
`modem to communicate in the network.
`16. The system of claim 12, wherein the first and second
`modems are configured to communicate with each other via
`the network node over the common master loop.
`17. The system of claim 12, wherein the first and second
`modems are configured to communicate in the network
`using signals compatible with ADSL standards.
`18. The system of claim 12, wherein the common master
`loop comprises a single twisted pair of conductors.
`19. A system for operating a modem in a network, the
`system comprising:
`means for initializing the modem to communicate with a
`network node via a master loop; and
`means for releasing a portion of communication band
`width used by the modem, upon receiving a signal from
`the network node, for one or more communication
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`US 7,031,380 B1
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`8
`terminals coupled to the network node via the master
`loop, wherein the modem releases the portion of the
`communication bandwidth while maintaining a Super
`frame of the communication bandwidth.
`20. The system of claim 19, wherein
`the modem is configured to communicate with the net
`work node using time division multiplexing; and
`the modem releases one or more time frames for the one
`or more communication terminals.
`21. The system of claim 19, wherein
`the modem is configured to communicate with the net
`work node using frequency division multiplexing; and
`the modem releases one or more frequency tones for the
`one or more communication terminals.
`22. The system of claim 19, wherein the modem and the
`one or more communication terminals are configured to
`communicate in the network using signals compatible with
`ADSL standards.
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