JP2002520902A - Source adaptive digital subscriber line and method - Google Patents

Abstract

(57) Abstract: A communication system comprising: a plurality of subscribers having a telephone set and various types of home modems connected using a twisted pair to a local server having a plurality of downstream repeaters; and a subscriber line of the twisted pair. A central office connected to the local server using The central office comprises a telephone switch for providing telephone service to the subscriber and a concentrator for connecting a plurality of upstream repeaters to a number of office modems for providing data service to the subscriber. Communication systems use CAP or DMT line signals in a time sharing manner. The line signal is transmitted with various time framing. All subscriber lines can operate in one of three operating modes: asymmetric, semi-asymmetric, and symmetric. The office modem is connected to the office modem in the current transmission cycle, depending on the type of information source and the subscriber's home modem, the mode of operation of the subscriber line and the downstream / mode of operation. Change the upstream bit rate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to data communications, and more particularly to a Digital Subscriber Line on a telephone cable.

[0002]

BACKGROUND OF THE INVENTION

Digital Subscriber Line (DSL), a new modem technology, converts the current twisted pair telephone line into access paths for multimedia and high-speed data communications. The most successful Asymmetric Digital Subscriber Line (ADSL) is 6 Mbps
Send more to the subscriber, about 640 kbps, in both directions. Such rates (
rate) increases current access capacity by more than 50 times without new cable installations. ADSL can actually transform today's public information networks into powerful, ubiquitous systems that can transport multimedia, including those limited to voice, text and low-resolution graphics, to homes, including full-motion video.

An ADSL circuit connects an ADSL modem to each end of a twisted pair telephone line and provides three information channels: a high-speed downstream channel, a medium speed duplex channel, and a POTS ｛. Create a simple Plain Old Telephone Service @ Chanel.
The POTS channel is disconnected from the digital modem by a filter, thus ensuring uninterrupted POTS even if ADSL fails. The high speed downstream channel ranges from 1.5 to 6.1 Mbps while the duplex rate (duplex rat)
e) ranges from 16 to 640 kbps. Downstream data rate (downstream da
ta rates are the length of the copper wire, its wire gauge, bridged taps
) Depends on a number of factors, including the number and inter-coupled disturbances. Line attenuation increases with line length and frequency, and decreases with increasing wire diameter. If the bridge tap is ignored, ADSL operates as follows.

Data rate Wire size Distance 1.5 MBPS 0.5 mm 5.5 km 1.5 MBPS 0.4 mm 4.6 km 6.1 Mbps 0.5 mm 3.7 km 6.1 Mbps 0.4 mm 2.7 km One problem is real Telephone cables have a large number of bridge taps, which significantly reduces line length. Another problem is that flat telephone cables are used to route to the building. In fact, these problems make it impossible to provide 6.1 Mbps service to more than 30% of the subscribers. The ADSL home modem is a very complex and expensive device. ADSL Central Office Equipment is also very expensive, because every subscriber line must have its own ADSL Office Modem. The cost of central office ADSL equipment is as high as about $ 300 per subscriber.

[0005] ADSL modems were developed to maximize operation for all available lines. The result is a very high performance modem, but not necessarily the most cost effective solution.

ADSL is not cost effective for the following reasons.

ADSL or remote exchanges are about 2,743 from the exchange
Connect customers located at distances up to m (9000 feet). Obviously, the highest performing ADSL is not needed for such a short line. More economical solutions are needed.

[0008] Current ADSL requires one dedicated central office (CO) unit for all customers. This is a very inefficient concept, since there is always a very large number of central office units that are not used because most of the time only a small part of the line is used. This inefficiency adds cost per line and space for ADSL equipment installation. The same service becomes centralized with the C.I. It can be provided with a smaller number of units on the O side.

[0009] ADSL is the customer and the C.I. Designed to maximize the data rate on the connection to O, however, this is usually not a limiting factor. As current Internet communications are today limited by the Internet's backbone, the increased ADSL data rates will result in higher end-to-end communications.
d to end communication) is no longer translated. This is recently G. That is why the G.lite standard has specified lower targets for the data rate.

[0010] ADSL is currently available from C.I. It is a very complex and expensive device both on the O and the customer side.

ADSL has been defined to maximize data rates without considering the characteristics of various applications. Some applications require high downstream bit rates, such as high quality video, while having very low upstream bit rates. Other applications require intermediate range symmetric data rates, such as video conferencing. Current ADSL supports both the maximum uplink and downlink data rates simultaneously. The result is a more complex solution that supports more than is actually needed.

[0012] From another perspective, ADSL is a very redundant system, in which ADSL uses Information Source Characteris
tics) without regard to telephone cable bandwidth.

[0013] Another problem with current ADSL systems is that only one computer of the subscriber may be connected to the Internet service at the same time.

[0014] In the United States, about 15,000 subscribers have at least two computers at home and it is not possible to connect all home computers to the Internet with the same twisted pair, so current ADSL service The limitations are an obvious drawback.

[0015]

Summary of the Invention

In accordance with the present invention, disadvantages and problems associated with ADSL systems are substantially reduced or eliminated. In particular, Source Adaptiv Digital Subscriber Line
e Digital Subscriber Line (SADSL) provides subscribers with three modes of operation, asymmetric mode, half-asymmetric mode, and symmetric mode, depending on the nature of the information source. so,
Provide data services.

The SADSL uses QAM or DMT modulation (QMT) to transmit downstream and upstream data.
AM or DMT modulation) is used. The symbol rate of the upstream signal is several times less than the symbol rate of the downstream signal. SADSL is based on the time division method.
method) (TDM) to transmit downstream and upstream data on the same twisted pair of telephone cable. A SADSL transmission frame includes a downstream time interval for downstream symbols and an upstream time interval for upstream symbols. SADSL transmission frames have a fixed duration in any mode of operation, but the downstream and upstream time intervals have different durations in different modes of operation. Synchronization word
And a frame control word symbol are added to the downstream data symbol. The acknowledgment word symbol is appended to the upstream data symbol.

According to the invention, the information sources connected at the subscriber end of the SADSL are divided into three groups. That is, 1. Asymmetric information source. These sources require downstream of a high bit rate and produce only output control signals with very low bit rates.

Downstream Upstream This group includes:

Digital Television 6.1 Mbps 16 Kbps Digital Hyphened Audio 1.5 MBPS 16 Kbps Compressed Video 1.5 MBPS 16 Kbps This group concerns the following states; subscribers only receive data from network servers.

[0020] 2. Semi-asymmetric information source. These sources receive high bit rate downstream data and produce upstream data having a low bit rate.

Downstream Upstream This group includes the Internet .about.1.0 Mbps .about.100 Kbps This group concerns the following states; subscribers receive data from network servers and send data to network servers.

[0022] 3. Symmetric information source. These sources require upstream data and downstream data at the same intermediate bit rate.

Downstream Upstream This group includes video conferencing and video telephony 384 kbps 384 kbps This group pertains to the following states; information can be exchanged between subscribers.

Since the amount of information created by a single subscriber is significantly less than the amount of information created by a NetArc server, all current and future data services will be in one of the three groups described above.

The source adaptive digital subscriber line operates in one of three modes of operation, corresponding to three groups of information sources. The selection of the operation mode depends on the communication session (co
It is performed during the initialization phase of the mmunication session. Here, the communication session means a cycle of information exchange with the current information source. There are many communication sessions with various sources during one connection with the subscriber.

The SADSL central office supports the communication of different home modems located in the same house, and so on for different houses. Various upstream and downstream data bit rates may be supported. The process of initializing the connection to the subscriber performs the selection of the data bit rate.

According to the invention, the SADSL communication system is located at a plurality of subscribers' homes and is located at each subscriber's home, connected to a number of different information sources,
Includes multiple different home modems.

Each home modem has an information source analyzer and a frame control circuit for changing a transmission frame according to the type of information source connected to the home modem during the current communication session.

The SADSL communication system includes a central office connected to a plurality of twisted pair subscriber lines. The central office includes a number of central office modems that may operate with any home modem. Each C.I. It should be noted that an O-modem can support more than one customer. This function is provided by the C.I. This is achieved by connecting an O-modem to the subscriber line through an analog concentrator. All office modems use a home modem type analyzer (ho
me modem type analyzer, frame control circuit and bit rate adaptor (bit
rate adapter). The office modem changes its transmission frame structure and upstream / downstream bit rate according to the type of the subscriber's home modem and the type of information source currently connected to the office modem. The number of office modems is less than the number of subscriber lines.

According to one embodiment of the present invention, the communication system comprises a local server.
). The local server is located at the subscriber end of a plurality of twisted pair subscriber lines routed to a building or telephone booth. The local server includes a plurality of downstream repeaters connected to a twisted pair subscriber line. The downstream repeater amplifies the downstream signal and splits the twisted pair subscriber line into a twisted pair data line and a twisted or flat pair telephone line.

According to another embodiment of the present invention, a communication system comprises a central office including a plurality of upstream repeaters connected to a twisted pair subscriber line. The upstream repeater amplifies the upstream signal and splits each twisted pair subscriber line into a downstream data line, an upstream data line, and a twisted or flat pair telephone line.

According to another embodiment of the present invention, a communication system comprises a number of line repeaters connected to a twisted pair subscriber line. The line repeater amplifies upstream and downstream signal levels. The line repeater uses a synchronization block (sync
hronization block) and a frame control circuit connected thereto. The synchronization block receives a downstream synchronization signal.

According to another embodiment of the present invention, the communication system consists of several home modems on the subscriber end connected to the same twisted pair. Every modem is connected to its own source of information. All home modems have an information source analyzer and a frame control circuit that, during the current communication session, change the transmission frame according to the type of information source connected to the home modem.

[0034] All home modems include a super-frame control circuit that creates different transmission frames for different active home modems.

Control of the superframe circuit of some home modems is achieved in current communication sessions by a central office modem connected to the subscriber line. This means that the office modem transmits data, for example, to one active home modem during a first transmission frame and to another active home modem during a second transmission frame. I do. The superframe includes, for example, four transmission frames. All transmitted frames operate in one of three modes of operation, according to the connected information source. During transmission of the third and fourth frames of the superframe, data is transmitted between active home modems. This is the SA of this embodiment.
This means that the DSL system not only provides the DSL service but also includes the home digital network function, that is, the ability to communicate between the units located at the customer premises.

According to another embodiment of the present invention, the communication system comprises one or several home modems at the subscriber end and a digital telephone set connected to the same twisted pair. The digital telephone set is a PCM or ADM codec
And a frame control circuit coupled to the synchronization block. This block receives the downstream synchronization signal. The audio signal is coded by a PCM or ADM codec and transmitted during a portion of the time interval reserved for control data and synchronization signals.

Important technical advantages of the present invention include the ability of SADSL to adapt the characteristics of home and office modems to the characteristics of current information sources. This advantage makes it possible to develop a simple home modem that meets all needs of the subscriber.

Another important technical advantage of the present invention includes the ability of SADSL to work with various types of home modems and supports many different downstream and upstream data bit rates.

The SADSL communication system simultaneously serves a number of inexpensive home modems with low data bit rates and a number of expensive home modems with high data bit rates.

Another important technical advantage of the present invention is that the SADS using a simple repeater
Includes the ability to amplify and split the L line signal. The SADSL communication system has no limitations on cable length and bridge taps. In practice, all subscribers of the current telephone network may be connected to the SADSL communication system.

Another important technical advantage of the present invention includes the ability to service multiple subscriber home modems with a reduced number of office modems. This advantage is
Makes ADSL systems a more economical solution than current ADSL systems.

Another important technical advantage of the present invention is that DSL service (DSL service) and home digital networking service (Home digital
networking service) at the same time.

Another important technical advantage of the present invention includes the possibility to provide digital telephone service over the same twisted pair used for DSL and POTS services. It should be noted that the invention is independent of the line code. The present invention relates to base band modulation such as PAM.
Is a single carrier modulation such as QAM or CAP
Or a modem that utilizes multicarrier modulation, such as discrete multitone (DMT).

One important embodiment of the present invention is based on several variants of the current ADSL standard. This variant is a special standard specified for the Japanese market and is known as G. dmt annex C. Some minor changes to this standard set the basis for the practice of the present invention.

[0045]

[Detailed description]

FIG. 1 illustrates a communication system 20 that provides telephone and data services to a subscriber 22. The subscriber 22 is connected to a local server 24 using a local data line 26 for data communication and a local telephone line 28 for telephone communication. The local data line 26 and the local telephone line 28 may use a twisted pair or a flat pair. The central office 30 is connected to the local server 24 using a twisted pair subscriber line 32. Subscriber line 32
Will support telephone and data services simultaneously.

The subscriber 22 includes a telephone 34 and a home modem 36. Telephone 34 is connected to local telephone line 28. Home modem 36 is connected to local data line 26. Telephone 34 is a traditional telephone transceiver or any other device suitable for enabling voice communication over telephone line 28.

The home modem 36 sends and receives data within the communication system 20 using QAM or DMT modulated signals. The home modem 36 is connected to three groups of information sources: a symmetric group 38, a semi-asymmetric group 40, and an asymmetric group 42.

The symmetric source 38 has the same intermediate range bit rate for both the upstream and downstream directions. One example of this source is a video phone. Semi-asymmetric source 4
0 receives the high bit rate downstream and makes the upstream with a low bit rate. An example of this source could be a personal computer connected to the Internet. Asymmetric source 42 receives the high bit rate downstream data and produces only output control signals having a very low bit rate. One such source is digital television.

The communication system 20 includes a number of other twisted pair subscriber lines 32 connected to other subscribers 22 through a local server 24. In the exemplary embodiment, central office 30 provides 1,000 subscribers 22 with telephone and data services. Local server 24 provides telephone and data services to all subscribers in the building and includes a number of downstream repeaters 44 according to the number of subscribers. Downstream repeater 44 increases the level of the downstream signal received from the central office,
The data and telephone signals are separated and transmitted to the subscriber 22 using a local twisted pair 26 for data and a local telephone line 28 for telephone.
Line repeaters 45 that increase the level of downstream and upstream line signals may be included in long subscriber lines 29,31.

The central office 30 includes a number of upstream repeaters 46 connected to the subscriber line 32, a number of office modems 58, a concentrator 56, a telephone switch 54, and a network device 72.

The upstream repeater 46 raises the level of the upstream signal received from the subscriber 22 and converts the data and telephone signals into three lines: a telephone line 48 and a downstream data line 5.
0 and split into upstream data lines 52.

The telephone line 48 is connected to a telephone switch 54. The telephone switch 54 of the central office 30 is a simple plain telephone system (P
OTS) service is provided to the subscriber 22.

The downstream data line 50 and the upstream data line 52 are connected to a concentrator 56.
The concentrator connects a number of subscribers 22 to a number of office modems 58 using a modem up line 60 and a modem down line 62.

The concentrator 56 provides an electrical connection between a number of subscribers 22 and a number of office modems 58. The number of office modems 58 is less than the number of subscribers 22.

The concentrator 56 performs off-hook detection to determine whether the subscriber 22 desires a data service. The data off-hook detector in concentrator 56 can use one of several methods to determine whether subscriber 22 should be connected to office modem 58. The off-hook detector of the communication server 56 may determine whether the subscriber 22 requires data access by direct line current, voltage, electrical tones, data link frames, or some other protocol or The sequencing of the data may be monitored.

The next trigger for connecting a subscriber line through the concentrator is the DM of the present invention.
Of particular importance for the implementation of T (ADSL-based). Detection of the appropriate activation / service solicitation signal coming from the CPE side; The unique activation / G.hs signal used to initiate the ADSL connection
) Can be made by a simple detector designed to detect this. This trigger is used once the ADSL link is first established. -Energy detection on the upstream passage. This trigger is used to reconnect the current link when both sides remain synchronized. Data transfer upon detection of this trigger occurs almost immediately and does not require a re-train process.

[0057] The concentration session includes the following steps. Detection of some activation signals coming from the CPE side as explained before. C. to active lines through the concentrator. O Modem assignment. On detection of "no activity" on the line, e.g., receiving an idle cell during some predefined period-the C.I. Temporary interruption of line on O side. The CPE and C.I. during this temporary interruption; Synchronization is maintained between the O modems.
This synchronization eliminates the need for a long retrain process. It is implemented by continuous transmission of pilot tones (implementation of DMT) even during the temporary interruption time. -Upon detecting activity, the active line will send any available C.I. Reconnect to the O modem. Since the line parameters are already known and stored in the system, the data connection is re-established within a short time.

To allow synchronization during the temporary shutdown period, all C.I.s connected to the same concentrator O modems use the same clock source. If a DMT line code is used, the pilot tones are generated from one source at the concentrator and distributed over all lines. The C.I. O-modems do not themselves generate the pilot tone even during normal operation-instead the pilot carrier is always added at the concentrator.

The central office 30 is connected to an office modem 58 by a data line 74 and a network device 72 connected to a data network 76 by a network line 78.
Contains.

One embodiment of the communication system 20 uses QA to transmit upstream and downstream line signals.
Use M or CAP modulation. There are four levels of line signals depending on the required bit rate.

A. Level 1 uses QAM4 for upstream and downstream.

B. Level 2 uses QAM 16 for upstream and downstream.

C. Level 3 uses QAM64 for upstream and downstream.

D. Level 4 uses QAM256 for upstream and downstream.

The office modem 58 operates at four levels of line signals. The current level of line signal of office modem 58 depends on the type of home modem 36 connected by the subscriber during the current communication cycle. The home modem 36 may vary and may support one or several levels of line signals.

Grade 1 of the simplest home modem supports only level 1.

Grade 2 of the home modem supports Level 1 and Level 2.

Grade 3 of the home modem supports Level 1, Level 2 and Level 3.

All grade 4 home modems support four levels of line signals.

Another embodiment of communication system 20 uses DMT modulation for transmission of upstream and downstream data transport cells 90 and QAM modulation for transmission of synchronization word 88, frame control word 89 and acknowledgment word 92. I do. All tones of the DMT can be modulated by QAM4, QAM16, QAM64 and QAM256. Depending on the type of modulation, there are four corresponding levels of the DMT line signal.

The communication system 20 has three modes of operation according to the type of information source used by the subscriber for the current transmission session: asymmetric, semi-asymmetric and symmetric modes of operation. There are three possible transmission frame structures depending on the operation mode.

FIG. 2 illustrates the transmission frame structure (for QAM home modem grade 1) for asymmetric mode in one embodiment of the present invention. The transmission frame 80 has a fixed duration of 4 ms, a downstream time interval 82, an upstream time interval 84 and a gap time 86.
including. The downstream time interval 82 includes a synchronization word (SW) 88 and a control word (CW).
89 and subsequent 16 data transport cells (DTC) 90 containing downstream data. The upstream time interval 84 includes only an acknowledge (AK) 92. Gap time (G
I) 86 is a guard time for the next transmission frame.

FIG. 3 shows a transmission frame structure (QAM) for a semi-asymmetric operation mode in one embodiment of the present invention.
Figure 1 illustrates a grade 1) home modem. Downstream time interval 8 in this mode
2 includes SW88, CW89 and ten DTCs 90. Upstream time interval 8
4 includes AK92 and two DTC90.

FIG. 4 illustrates a transmission frame structure for a symmetric operation mode (grade 1 of a QAM home modem) in one embodiment of the present invention. In this mode, downstream time interval 82 includes SW 88, CW 89, and four DTCs 90. Upstream time interval 84 includes AK 92 and four DTCs 90.

FIG. 5 illustrates the structure of the data transport cell 90. Synchronous transfer mode (
In Synchrony Transfer Mode (STM), DTC 90 has two downstream data channels, AS0 and AS1, and two upstream data channels, LS.
0 and LS1 are supported. In this mode, the DTC 90 has one control byte,
4 bytes of the AS1 / LS1 channel, 48 bytes of the AS0 / LS0 channel, and 8 bytes of a Rid-Solomon Code. In Asynchronies Transfer Mode (ATM), DTC
Numeral 90 includes 53 bytes of the ATM cell and 8 bytes of the Lido-Solomon code. Communication system 20 uses the same synchronization word (SW) 88 and different codes for control word 89 and acknowledge 92 corresponding to the mode of operation and the current data bit rate. The control word (CW) 89 indicates in which operating mode the system must operate in the current transmission frame and which type (grade) of home modem is connected to the subscriber end. Notify all devices (home modem, office modem, repeater) connected to the subscriber line.

The frame synchronization word 88, control word 89, and acknowledge 92 are transmitted at the lowest level of modulation (QAM4) for any grade of modem. The data transport cell 90 has QAM4 for level 1, QAM16 for level 2, and level 3
For QAM64 and QAM256 for level 4.

Table 1 shows the number of QAM upstream and downstream DTCs 90 in one embodiment of the present invention for various modes of operation. This data was calculated for a transmitted frame of 4 ms duration, a 1080 kHz symbol clock downstream and a 360 kHz symbol clock upstream.

[0078]

[Table 1]

Table 2 shows the transmission capabilities of the communication system 20 (with ATM cells) according to one embodiment of the present invention. This data was calculated for a 4 ms duration transmit frame, a downstream 1080 kHz symbol clock and an upstream 360 kHz symbol clock.

[0080]

[Table 2]

Table 3 shows the transmission capacity (in the STM mode) of the communication system 20 according to one embodiment of the present invention.
Is shown. This data is transmitted frame of 4 ms duration, 1080 kHz downstream
And a 360 kHz symbol clock upstream.

[0082]

[Table 3]

FIG. 6 shows a transmission frame structure for an asymmetric operation mode according to another embodiment of the present invention.
2 illustrates a DMT home modem grade 1). Transmit frame 80 has a constant duration of 4 ms and includes a downstream time interval 82, an upstream time interval 84, and a gap time 86. The downstream time interval 82 includes a synchronization word (SW) 88, a control word (CW) 89 and 24 data transport cells (DTC) 9 containing the next downstream data.
Contains 0. The upstream time interval 84 includes only an acknowledge (AK) 92. The gap time (GI) 86 is used for protecting the next transmission frame. All DTC90
Is coded by DMT modulation using 244 tones with QAM4. All downstream DTCs 90 are converted to one 125 μs DMT symbol and all upstream
C is converted to one 375 μs DMT symbol.

FIG. 7 illustrates a transmission frame structure for semi-asymmetric operation mode (DMT home modem grade 1) in another embodiment of the present invention. In this mode, downstream time interval 82 includes SW88, CW89 and 15 DTC90. Upstream time interval 84
Includes AK92 and three DTCs 90.

FIG. 8 shows a transmission frame structure (D) for a symmetric operation mode according to another embodiment of the present invention.
2 illustrates a grade 1) MT home modem; Downstream time interval 8 in this mode
2 includes SW88, CW89 and six DTCs 90. The upstream time interval 84 is A
Includes K92 and six DTCs 90.

The communication system 20 uses the same frame synchronization word (SW) 88 and control word 89
Acknowledgment 92 corresponds to the mode of operation and the current data bit rate. The control word (CW) 89 tells all devices (home modem, office modem, repeater) connected to the subscriber line in which operating mode it must operate in the current transmission frame and which Indicate if a type (grade) home modem is connected to the subscriber end.

The frame synchronization word 88, control word 89 and acknowledge word 92 are transmitted using QAM4 for any grade of modem. Data transport cell 9
0 is transmitted with DAM using 244 tones using QAM4 for level 1, QAM 162 for level 2, QAM 64 for level 3 and QAM 256 for level 4.

Table 4 shows the number of upstream and downstream DTCs 90 in the DMT for another embodiment of the present invention for various modes of operation. This data was calculated for a transmitted frame of 4 ms duration.

[0089]

[Table 4]

Table 5 shows the transmission capabilities (in ATM cells) of the communication system 20 in a DMT embodiment of the present invention. This data was calculated for a transmitted frame of 4 ms duration.

[0091]

[Table 5]

Table 6 shows the transmission capabilities (in STM mode) of the communication system 20 in a DMT embodiment of the present invention. This was calculated for a transmitted frame of 4 ms duration.

[0093]

[Table 6]

FIG. 9 illustrates the home modem 36 of one embodiment of the present invention in more detail.

The home modem 36 includes a line transformer 100 connected to the twisted pair 26,
Upstream amplifier 102 connected to transformer 100 and QAM modulator 104, transformer 1
00 and QAM demodulator 108, downstream amplifier 106, QAM demodulator 10
8 and a frame synchronizer 110 connected to a frame control circuit 112, and a digital interface 12 connected to a QAM modulator 104 and a QAM demodulator 108.
2 and an information source analyzer 120 connected to the acknowledgment generator 118. The information source analyzer 120 and the digital interface 122 are connected to the symmetric information source 38 by a digital line 128, the semi-asymmetric information source 40 by a digital line 130, and the asymmetric information source 42 by a digital line 132.
Connected to. Acknowledge generator 118 is connected to QAM modulator 104.

The downstream signal received from the twisted pair 26 is converted by the QAM demodulator 108. The decoded binary sequence of downstream data is transmitted to the frame synchronizer 110 and the digital interface 122. The digital interface 122 decodes downstream data transport cells and provides communication with information sources 38,40,42. The digital interface 122 supports many different protocols of exchange, such as a PCI bus, an ISA bus, or any other suitable technique for providing input / output capabilities to the information source. The frame synchronizer 110 produces the downstream and upstream symbol clocks from the downstream signal and detects the frame synchronization word 88 and the control word 89 transmitted by the central office 30.

The frame synchronizer 110 is connected to a frame control circuit 112, which changes the transmission frame structure according to FIGS. 2, 3 and 4 according to the received control word 89. The frame control circuit 112 controls the downstream amplifier 10 depending on the current operation mode.
2 and the upstream amplifier 106 are switched on and off, and a corresponding control signal is applied to the downstream repeater 44 using a control line 134 connected to the midpoint of the primary winding of the transformer 100.
Send to

The upstream data is routed from one of the information source lines 128, 130, 132 to the digital interface block 122, which converts the upstream data to transport cells 90. Acknowledge generator 118 adds acknowledge word 92 to the transport cell data. The upstream binary data is converted to a QAM line symbol by a QAM modulator 104, which is connected to an upstream amplifier 102. The upstream amplifier 102 transmits the upstream QAM line signal to the twisted pair 26.

The communication system 20 simultaneously services many different home modems 36 from the simplest home modem grade 1 to the most complex home modem grade 4. The complex home modem frame synchronizer 110 controls the
Connected to AM modulator 104 and to QAM demodulator 108 by control line 107. Both QAM modulator 104 and QAM demodulator 108, depending on the current control word 89 received by synchronizer 110, may be QAM4 or QAM16 or QAM4.
Supports AM64 or QAM256 modulation.

FIG. 10 illustrates the downstream repeater 44 in detail. Downstream repeater 44 includes a local transformer 200 connected to local data line 26, downstream amplifier 206, and upstream buffer 208. The midpoint of the primary winding of transformer 200 is connected to frame control circuit 210 by control line 218. The frame control circuit 210 is connected to an enable input 214 of the upstream buffer 208 and an enable input 216 of the downstream amplifier 206. Lowpass filter 202
Is connected to the local telephone line 28 and the line transformer 204. Line transformer 204 is connected to the output of upstream buffer 208, the input of downstream amplifier 206, and to twisted pair subscriber line 32. The frame control circuit 210
Is connected to the downstream amplifier 206 and the upstream buffer 20 according to the signal on the control line 218.
Switch 8 on / off. This frame control signal is transmitted to the local data line 2
6 comes from the home modem.

FIG. 11 illustrates the line repeater 45 in detail. The line repeater 45 first includes a transformer connected to the twisted pair 29 routed from the subscriber, the input of the upstream amplifier 154, and the output of the downstream amplifier 156. Second
The transformer 158 is connected to the twisted pair 31 routed from the central office, the low-pass filter 152, the output of the upstream amplifier 154, and the input of the downstream amplifier 156. QAM demodulator 160 is connected to second transformer 158 and frame synchronizer 162. Frame control circuit 164 includes a frame synchronizer 162, an enable input 166 of upstream amplifier 154, and a downstream amplifier 156.
Is connected to the enable input 168. QAM demodulator 160 converts the downstream signal received from twisted pair 31. The decoded binary sequence of downstream data is sent to frame synchronizer 162.

The frame synchronizer 162 generates the downstream and upstream symbol clocks and detects the frame synchronization word 88 and the control word 89 transmitted by the central office 30.

The frame synchronizer 162 depends on the received control word 89 in FIGS.
Is connected to a frame control circuit 164 that changes the transmission frame structure in accordance with The frame control circuit 164 switches on / off the downstream amplifier 156 and the upstream amplifier 154 depending on the current operation mode.

FIG. 12 illustrates the upstream repeater 46 in detail. The upstream repeater 46 is connected to a line transformer 250 connected to the subscriber line 32, a low-pass filter 252 connected to the line transformer 250 and the telephone line 48, and connected to the line transformer 250 and the upstream data line 52. An upstream amplifier 254; a downstream buffer 256 connected to the line transformer 250 and the downstream data line 50;
54, an enable input 260 at the downstream, an enable 262 at the downstream buffer 256, and a frame control circuit 258 connected to the control line 51. The frame control block 258 turns on / off the downstream buffer 256 and the upstream amplifier 254 according to a frame control signal transmitted from the office modem 58 through the concentrator 56.
Switch off.

FIG. 13 illustrates the office modem 58 in detail. The office modem 58 includes an upstream amplifier 300 connected to the up data line 52 and a down data line 50.
And a downstream amplifier 302 connected to the The frame control circuit 304 has an enable input 306 of the upstream amplifier 300 and an enable input 3 of the downstream amplifier 302.
08 and the control line 51. The output of the upstream amplifier 300 is Q
Downstream amplifier 3 connected to the input of AM demodulator 310 and the output of QAM modulator 312
02 input. The output of QAM demodulator 310 is connected to synchronizer 322, bit rate adaptor 328, and acknowledge receiver 316. The acknowledge receiver 316 is connected to a frame processor 314 and a home modem type decoder 318. The frame processor 314 includes a synchronization word generator 330, a control word generator 332, and a frame control circuit 3
04. Frame processor 314 is connected to central office concentrator 56 using service line 86. The synchronization word generator 330 and the control word generator 332 are connected to the QAM modulator 312.

The bit rate adaptor 328 is connected to the QAM modulator 312, the QAM demodulator 310, and the digital interface 320. The digital interface 320 uses the network data line 76 to
Connected to Oscillator 315 is connected to frame processor 314 and provides a downstream clock.

The upstream signal received from the twisted pair 52 is converted by the QAM demodulator 310. The decoded binary sequence of upstream data is sent to acknowledge receiver 316, synchronizer 322, and bit rate adaptor 328.

The bit rate adaptor 328 decodes the received upstream data transport cell 90 and sends the binary data to the digital interface 320. The digital interface 320 provides the network device 72 for communication. The digital interface 320 connects to a PCI bus, ISA bus, or data network.
It supports many different protocols of exchange, such as any other suitable technique for providing output capabilities. The synchronizer 322 produces an upstream symbol clock from the received upstream signal.

The acknowledge receiver 316 receives the acknowledge 9 issued from the home modem 36.
2 and sends them to a home modem type decoder 318 and a frame processor 314.

The home modem type decoder 318 analyzes the received acknowledgment and the fix information about the characteristics of the home modem 36 currently connected to the office modem 58. In accordance with this information, the home modem type decoder 318 provides a corresponding level of modulation, ie, QAM4 or QAM1.
The bit rate adaptor 328, QAM modulator 312 and QAM demodulator 310 are switched to support 6 or QAM 64 or QAM 256 and the corresponding upstream and downstream data bit rates.

The frame processor 314 includes a synchronization word generator 330 and a control word generator 3
Then, a control signal is supplied to the frame control circuit 304. The frame processor 314 analyzes the acknowledgment 92 sent by the home modem 36 and changes the transmission frame structure as shown in FIG. 2, FIG. 3, and FIG.

The actual frame structure depends on the type of information source connected to the home modem 36 in the current communication session.

The frame control circuit 304 switches on / off the downstream amplifier 302 and the upstream amplifier 300 in accordance with a command issued from the frame processor, and supplies an upstream repeater frame control signal on the control line 51.

FIG. 14 is a flowchart illustrating the operation of the SADSL communication system 20 according to one embodiment of the present invention. While the concentrator 56 is switched on, the home modem 36
And the office modem 58 is in a standby state 400. The concentrator 56 is waiting for hook-off detector activity. Upon detecting 401 a data service need, the concentrator 56 selects 40 the active subscriber 22 and the available office modem 58.
2,403. The concentrator 56 switches its internal relay directly to make the appropriate connection 404 between the subscriber and the selected office modem 58.

When the connection is established, the concentrator 56 sends an wake-up signal to the selected office modem 58 405 and puts the office modem 58 in the initialization state 411. In this state, the office modem 58 starts operating and sends 412 the home modem 36 a sequence of initialization transmission frames corresponding to the symmetric mode of operation (FIG. 4). The initialization transmission frame includes a synchronization word 88, an initialization control word, and an idle data transport cell 90. An idle transport cell contains a special sequence of QAM or DMT test symbols.

In the standby state 400, the home modem 36 waits for a downstream signal 423, and the frame control circuit 112 controls the downstream amplifier 106 and the downstream repeater 4 of the home modem 36.
The fourth downstream amplifier 206 is turned on. During the initialization procedure, the home modem 36
The synchronizer 162 fine-tunes 424 the downstream and upstream clocks of the office modem to synchronize the transmitted frames of the office and home modems. After the completion of the synchronization process, 425, the home modem 36 switches to symmetric mode operation (FIG. 4) and sends a "Synchronization OK" acknowledge to the office 426. Decoding this acknowledge 413 causes the office modem 58 to switch to a "Home Modem Type Detection" study 414. In this study, the office modem 58 sends a request to the home modem 36 and receives 427 a "modem type" acknowledge. A home modem type decoder 318 analyzes the received acknowledgment and, depending on the type of home modem 36 connected to the office modem 58 in the current communication cycle, the QAM modulator 312 of the office modem 58 and The QAM demodulator 310 is switched. At the same time, decoder 326 switches the bit rate adaptor 328 properties to adapt the bit rates of home modem 36 and office modem 58. The next study of the initialization process is trimming 428. It starts 415 upon receipt of the control word 89 "fine start" from the central office. In this study, the QAM or DMT test symbols are used to fine tune the gain and frequency characteristics of the downstream amplifier 106 of the home modem 36 and the upstream amplifier 300 of the office modem 58. When the fine tuning process is completed, the home modem 36 sends 429 a "fine tuning OK" acknowledge to the office modem. Upon receiving a "fine tune OK" acknowledge 416, the office modem 58 sends a "start" control word to the home modem 417. According to this command, the home modem 36 switches on the information source analyzer 120 which checks which information source (symmetric, semi-asymmetric or asymmetric) is waiting for data access. According to the "source type",
The acknowledgment word 92 is sent 430 to the office modem. According to the received "source type acknowledge", the office modem 58 generates 418 a corresponding "transmit frame control word" 89. After receiving the "transmit frame control word" 89, all devices (office modem, home modem, repeater) connected to the subscriber line change their transmit frame structure created by the frame control circuit, and 431 to start from. Upon changing the frame structure, the office modem sends an "access enable" control word 419. The next study is the information exchange 420 between the subscriber information source and the network device. After the communication exchange is completed 407, the concentrator 56 sends a stop command to the office modem 58 408, the office modem 58 sends a "stop control word" to the home modem 36, and the home modem 36 sends a "stop acknowledge". Return 432 and the home modem switches 400 to the standby state. The office modem 58 informs the concentrator 56 that the communication session has ended 422. The concentrator places the office modem in the standby state.
9. Disconnect 410 the office modem from the corresponding upstream repeater.

FIG. 15 illustrates a communication system 500 that simultaneously provides telephone, DSL and home network services to subscribers. Subscriber 22 is connected to central office 30 using a twisted pair subscriber line 32. The subscriber line 32 simultaneously supports telephone and data services between the central office 30 and the subscriber 22. Subscriber 22 includes telephone 34 and a number of home modems 505.
The telephone 34 is connected to the twisted pair subscriber line 32 by a low pass filter 501 that reduces noise in the voice bandwidth. Some home modems 505
Are directly connected to the subscriber line 32. All home modems 505 transmit and receive data using QAM or DMT modulated signals. All home modems 505
Is connected to an information source 40, which may be symmetric, semi-asymmetric or asymmetric. The home modem 505 connected to the same subscriber line may be of a different type and may support one or several levels of line signals as described above. All home modems 505 may be connected to central office 30 or another home modem 505. Control of the communication process is provided by the office modem 509 connected to the subscriber line 32 in the current communication cycle. FIG.
The communication system 500 depicted in FIG. 1 uses the same method as the communication system shown in FIG. 1, but uses more complex transmit framing. This framing includes a superframe structure containing a number of transmission frames. Each of the transmission frames can be used independently during communication of various home modems with one office modem or with another home modem.

FIG. 16 illustrates the home modem 505 in more detail.

The home modem 505 is connected to the line transformer 100 connected to the twisted pair 32.
And an upstream amplifier 102 connected to the transformer 100 and the QAM modulator 104, a downstream amplifier 106 connected to the transformer 100 and the QAM demodulator 108, and a connection to the QAM demodulator 108 and the frame control circuit 112. And a digital interface 122 connected to the QAM modulator 104 and the QAM demodulator 108, and an information source analyzer 120 connected to an acknowledgment generator 118. Information source analyzer 120 and digital interface 1
Reference numeral 22 denotes a digital line 128 connected to the symmetric information source 38, a digital line 130 to the semi-asymmetric information source, and a digital line 132 to the asymmetric information source 42. Acknowledge generator 118 is connected to QAM modulator 104. The superframe synchronizer 506 is connected to the frame synchronizer 110 and the superframe control circuit 504 connected to the frame control circuit 112.

FIG. 17 illustrates the office modem 509 in detail. Office Modem 509
Includes an upstream amplifier 300 connected to the up data line 52 and a downstream amplifier 302 connected to the down data line 50. The frame control circuit 304 is connected to the enable input 306 of the upstream amplifier 300, the enable input 308 of the downstream amplifier 302, and the control line 51. The output of upstream amplifier 300 is connected to the input of QAM demodulator 310 and the input of downstream amplifier 302 is connected to the output of QAM modulator 312. The output of the QAM demodulator 310 is
, A bit rate adaptor 328, and an acknowledge receiver 316. The acknowledge receiver 316 is connected to a frame processor 314 and a home modem type decoder 318. The frame processor 314 is connected to the synchronization word generator 330, the control word generator 332, and the frame control circuit 304. The frame processor 314 is a service line 86
Are connected to the central office concentrator 56. Synchronization word generator 33
The 0 and control word generator 332 is connected to the QAM modulator 312. The bit rate adaptor 328 is connected to the QAM modulator 312, the QAM demodulator 310, and the digital interface 320. Digital interface 32
0 is connected to the network device 72 using the network data line 76. Oscillator 315 is connected to frame processor 314 and provides a downstream clock. The superframe synchronizer 517 is connected to the frame processor 334 and the superframe control circuit 519 connected to the frame control circuit 519. Office modem 509 includes an initialization processor 521 that provides control of all blocks of office modem 509 at the beginning of the communication session.

FIG. 18 illustrates a superframe structure. The superframe 503 includes the four transmission frames 80 described above. Transmission frame 80 is a fixed 4m
s and has a downstream time interval 82, an upstream time interval 84, and a gap time 86. The downstream time interval 82 includes a synchronization word (SW) 88, a control word (CW) 89, and a next data transport cell (DTC) 90 containing downstream data.
And The upstream time interval 84 includes an acknowledge (AK) 92 and a next data transport cell (DTC) 90 containing upstream data. Gap time (GI)
86 is a guard time for the next transmission frame. Communication frame 0 has a different synchronization word (SF SW) 502 and is used for superframe synchronization. The superframe has a fixed duration of 16 ms. All transmission frames 80 of superframe 503 can be used independently for communication between office modem 509 and up to four active home modems 505 or for communication between up to eight home modems. . In the case of communication between home modems (home digital network), one communication frame 80 services two home modems 505. One of them transmits a QAM or DMT signal during the downstream time interval and receives a QAM or DMT signal during the upstream time interval. Another home modem 505 transmits QAM or DMT signals during the upstream time interval and receives QAM or DMT signals during the downstream time interval.

FIG. 19 is a timing diagram of a communication system 500 that provides DSL and home digital network services simultaneously. The office modem 509 operates in the super frame 503, and the home modem 1 (505) and the home modem 2 (505).
) And with the home modem 3 (505). All home modems are connected to the same twisted pair on the subscriber end of the system. Communication system 500 provides DSL service to home modem 1 during transmission frame 0 and transmission frame 1. During transmission frame 2 and transmission frame 3, communication system 500 provides a home digital network service between home modem 2 and home modem 3.

The office modem 509 transmits the transmission frame 80 to various home modems 5 of the subscriber.
05 may be programmed to be variously assigned. The office modem programming is performed by initializing the processor 521 at the beginning of the communication session. During this process, the office modem analyzes the received signal to detect, for example, the active home modem and the type of service required by the active home modem, and determines which framing structure is optimal. The information on the operating mode of this home modem and the allocation of transmission frames may be sent to each active home modem specified and defined. The initialization process can be implemented in many versions, but will not be described in detail in this description of the invention.

FIG. 20 illustrates a communication system 600 that provides digital telephone, DSL, and home network services to subscribers 22 simultaneously. Subscriber 22 is connected to central office 30 using a twisted pair subscriber line 32. The subscriber line 32 simultaneously supports digital telephone and data services between the central office 30 and the subscriber 22. Subscriber 22 includes a digital telephone set 601 and a number of home modems 505. A digital telephone set 601 and several home modems 505 are connected directly to the subscriber line 32. All home modems 505 transmit and receive data using QAM or DMT modulated signals. The digital telephone set 601 can be in digital form using QAM or DMT line signals, after ΔPCM or pulse code modulation or ADM or adaptive delta modulation code.
ng) After sending and receiving audio signal. In the case of the QAM modulation, the voice signal and the dialing signal are divided into a portion of the time allocated for the synchronization and control signals in the downstream time interval and a portion of the time allocated for the acknowledge in the upstream time interval. Sent. In the case of the DMT modulation, the dialing signal is transmitted in the same manner, but the voice signal is transmitted in data on the low frequency carrier during downstream and upstream time intervals. The central office 30 of the communication system 600 has a PCM or ADM codec 6 connected to an office modem 509 and a POTS frame relay 605.
03 is included.

FIG. 21 illustrates a time structure of a transmission frame in a communication system providing a digital telephone service. The upstream and downstream time intervals of the transmission frame 80 include the telephone codeword (V) 607. The telephone codeword is used for transmitting voice and dialing signals.

FIG. 22 illustrates a digital telephone set in a QAM application in more detail. The digital telephone set 601 includes the twisted pair 32, the transformer 100, and the QAM modulator 1.
04, the downstream amplifier 106 connected to the transformer 100 and the QAM demodulator 108, the QAM demodulator 108 and the frame control circuit 11.
2, a PCM coder 611 connected to the QAM modulator 104, and a PM connected to the QAM demodulator 108.
And a CM decoder (PCM decoder) 613. Microphone 615 is connected to the input of PCM coder 611. Telephone 617 is PCM decoder 61
3 is connected to the output. Dial operation and signal operation controller 619 is QA
The M modulator 611, the QAM demodulator 613, the frame synchronizer, and the dial operation keyboard 621 are connected. The power supply 623 is activated only during the hook-off telephone state and supplies power to all blocks of the digital telephone set 601. Power supply 6
23 supplied by central office like current analog telephone equipment (sources)
. At present, many companies have PCM including PCM coder 611 and PCM decoder 613.
It manufactures CMOS integrated circuits of M codec (PCM codec) 625. These are very inexpensive and micropower devices. Frame synchronizer 110
, QAM modulator 104, QAM demodulator 108, frame control circuit 112, dial operation and signal operation controller 619 can be implemented by ASIC technology of CMOS.
Finally, digital telephone set 601 may include only one CMOS IC that provides all the necessary functions for digital voice communication.

[0127]

[Possibility of industrial application]

The implementation of the present invention is very easy. Source adaptive digital subscriber lines may also be implemented on the basis of current ADSL systems. Today, the technology of ADSL using DMT signals is well-known, and Texas Instruments (TEXAS INSTRU
Semiconductor companies across the world, such as MENT), Analog Devices (ANALOG DEVICES), and Siemens (SIEMENS) have DMT signal processing chipset and ADSL analog front-end chips (Linear Technology) ｛Linear Technology (LINEAR TECHNOLOGY), TAI (TI), Alcatel (ALCATEL), and Analog Devices (ANALOG DEVICES). Most digital chips for DMT processing include a DSP that may be programmed to operate according to the method of the present invention. SADSL is completely compatible with current ADSL in frequency band and transmitted level. That means that SADSL and current ADSL can work without problems in the same cable. Furthermore, SADSL or ADS
It is possible to design a general-purpose office modem that can work with L home modems. The simplest SADSL modem can be included in a television set, video phone, high-fidelity audio system, and operates on the same subscriber line connected to an ADSL modem included in a personal computer. From another perspective, the use of repeaters can provide benefits to SADSL in long-haul subscriber lines.

Although the present invention has been described in the context of several embodiments, countless alterations, variations, modifications, and variations may be suggested by those skilled in the art, and the invention is herein described in detail. It is intended to cover such alterations, variations, modifications and variations that fit into the spirit and scope of the section.

[Brief description of the drawings]

FIG. 1 illustrates a communication system providing telephone and data services.

FIG. 2 illustrates a transmission frame structure in asymmetric mode for QAM SADSL.

FIG. 3 illustrates a transmission frame structure in QAM semi-asymmetric mode for SADSL.

FIG. 4 illustrates a transmission frame structure in a QAM SADSL symmetric mode.

FIG. 5 illustrates a data transport cell structure.

FIG. 6 illustrates a transmission frame structure in a DMT SADSL asymmetric transmission mode.

FIG. 7 illustrates a transmission frame structure in a DMT SADSL semi-asymmetric mode.

FIG. 8 illustrates a transmission frame structure in a DMT SADSL symmetric mode.

FIG. 9 illustrates a home modem in more detail.

FIG. 10 illustrates the downstream repeater in more detail.

FIG. 11 illustrates the line repeater in more detail.

FIG. 12 illustrates the upstream repeater in more detail.

FIG. 13 illustrates a central office modem in more detail.

FIG. 14 is a flowchart of a communication system operation.

FIG. 15 illustrates how the communication system simultaneously provides DSL and home network services.

FIG. 16 illustrates a home modem in detail.

FIG. 17 illustrates an office modem in detail.

FIG. 18 illustrates a transmission superframe structure in the configuration depicted in FIG.

FIG. 19 is a time diagram of a communication system that simultaneously provides DSL and home network services.

FIG. 20 illustrates a communication system that simultaneously provides DSL, home network and digital telephone services.

FIG. 21 illustrates the transmission of the frame structure of a communication system with digital telephone service in a QAM application.

FIG. 22 illustrates in detail a digital telephone set in a QAM application.

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Claims (15)

[Claims] 1. A digital subscriber line communication system over a telephone cable, comprising a plurality of asymmetric information sources, wherein the asymmetric information sources receive high bit rate downstream data and receive a plurality of subscriber information. Producing only an output control signal having a very low bit rate located at home, the system also comprises a plurality of semi-symmetric information sources, the semi-symmetric information source being the high bit rate downstream data. And generating upstream data having a low bit rate located at the home of the plurality of subscribers, the system further comprises a plurality of symmetric information sources, wherein the symmetric information sources are Having the same intermediate bit rate upstream and downstream data located at the home of the plurality of subscribers, and wherein the system is still located at the homes of the plurality of subscribers and And a plurality of different home modems connected to a number of different information sources, all of which include a frame synchronizer, an information source analyzer, and an acknowledgment generator. And a frame control circuit for changing a transmission frame of the home modem according to a type of the information source connected to the home modem within a current transmission cycle, the system further comprises: A plurality of twisted pair subscriber lines connected to the home modem of
The system still further comprises a central office connected to the plurality of twisted pair subscriber lines, the central office comprising a number of office modems, wherein the office modem is any of the home modems. Connected to the plurality of subscriber lines through a concentrator, each of the office modems being a frame synchronizer, an acknowledge receiver, a home modem type analyzer, a frame control circuit, and A bit rate adaptor, the office modem having its transmission frame structure according to the type of the home modem currently connected to the office modem and the type of the information source of the subscriber. A digital subscriber line communication system over a telephone cable, characterized by changing the upstream / downstream bit rate. 2. The communication system of claim 1 further comprising: a plurality of different home appliances located at the subscriber's home, connected to the same twisted pair subscriber line, and connected to a number of different information sources. A modem, wherein all of the home modems have a superframe synchronizer and a superframe control circuit that allocates various transmission frames for various home modems according to control signals received from the office modem. The system also comprises a number of office modems located at the central office, each office modem comprising a superframe synchronizer, a superframe control circuit, and an initialization processor. The office modem transmits transmission superframes for various home modems connected to the same twisted pair at the subscriber end. Communication system, characterized in that allocation of the various transmission frame beam during initialization process, made by the initialization Purosesa of the office modem at the beginning the initialization process for all communication sessions. 3. The communication system of claim 1 further comprising a plurality of home modems located at the subscriber's home, connected to the same twisted pair subscriber line, and connected to a number of different information sources. All the home modems can be programmed by the office modem for communication with the office modem and for communication with another home modem connected to the same twisted pair subscriber line. The system also includes a number of office modems located at the central office, each office modem including a superframe synchronizer, a superframe control circuit, and an initialization processor; The office modem transmits one or several transmission frames of the transmission superframe during the initialization process to the office modem of the home modem. And the different transmission frames are allocated for communication with each other connected to the same twisted pair on the subscriber end of the home modem, the initialization process being carried out by the office modem at the beginning of every communication session. A communication system performed by the initialization processor. 4. The communication system of claim 1 further comprising: a plurality of home modems located at the subscriber's home, connected to the same twisted pair subscriber line, and connected to a number of different information sources; A digital telephone set located at the subscriber's home and connected to the same twisted pair subscriber line, the digital telephone set comprising a frame synchronizer, a PCM or ADM codec, and dialing and signaling. Operating circuitry, the system also includes a number of office modems located at the central office, each office modem with a PCM or ADM codec, dial and signal operating circuitry, and A communication system comprising: a frame synchronizer. 5. The communication system of claim 1 further comprising a local server located at said subscriber end of a plurality of twisted pair subscriber lines routed to a building or telephone booth. The server has a plurality of downstream repeaters connected to the twisted pair subscriber lines, each downstream repeater amplifying the downstream signal and connecting the twisted pair subscriber lines with the twisted pair data lines and a twisted or flat pair telephone line. A communication system characterized in that: 6. The communication system of claim 2, further comprising a local server having downstream repeaters, each downstream repeater having a downstream amplifier, an upstream buffer, and a frame connected to the home modem by a twisted pair data line. A communication system comprising a control circuit. 7. The communication system of claim 1, further comprising a central office having a plurality of upstream repeaters connected to the twisted pair subscriber lines, each upstream repeater amplifying said upstream signal, A communication system wherein a twisted pair subscriber line is divided into a downstream data line, an upstream data line, and a twisted or flat pair telephone line. 8. The communication system of claim 4 further comprising a central office having upstream repeaters, each upstream repeater having an upstream amplifier, a downstream buffer, and a frame connected to the office modem by a concentrator. A communication system comprising a control circuit. 9. The communication system of claim 1, further comprising a plurality of line repeaters connected to the twisted pair subscriber line, each line repeater including a frame synchronizer, a downstream amplifier, and an upstream amplifier. And a frame control circuit connected to the frame synchronizer. 10. A method for transmitting and receiving downstream and upstream data using a twisted pair telephone cable in a digital subscriber line communication system, comprising the step of packing downstream data into data transport cells. And each of the data transport cells includes a fixed number of bits, the method also includes converting the data transport cells into downstream data blocks of QAM or DMT symbols, and synchronizing blocks of QAM symbols and QAM symbols. Creating a downstream control block; and, during a downstream time interval of a transmission frame having a fixed duration, the synchronization block of a QAM symbol, the control block, and a downstream data block of a QAM or DMT symbol. Sequential transmission at downstream bit rate and data transport cell with fixed number of bits of upstream data Packing; converting the data transport cells to upstream data blocks of QAM or DMT symbols; creating upstream acknowledge blocks of QAM modulation symbols; and the upstream time of a transmission frame having a fixed duration. During the interval, sequentially transmitting the upstream acknowledge block and the upstream data block of QAM or DMT symbols, the upstream symbol rate being several times lower than the downstream symbol rate; The method comprises changing a transmission frame structure according to the type of information source connected to the subscriber line within a current communication session, the method comprising different durations of the downstream and upstream time intervals. Three different transmission frame structures having a symmetric structure corresponding to the same downstream and upstream data bit rates;
Comprising generating a semi-asymmetric structure corresponding to said high downstream data bit rate and low upstream data bit rate, and an asymmetric structure corresponding to very high downstream data bit rate and very low upstream data bit rate. A method for transmitting and receiving downstream and upstream data using a twisted pair telephone cable in a digital subscriber line communication system. 11. The method of claim 10, further comprising: packing a number of transmission frames into superframes; allocating the transmission frames of the superframe to various communication channels; and providing two communication devices for each communication channel. Allocating, and sequentially transmitting a number of transmission frames included in the superframe, each transmission frame including a synchronization block, a QAM symbol control block, and a communication block for this communication channel. A method comprising having assigned downstream data from said first communication device and upstream data from a second communication device. 12. The method of claim 10, further comprising transmitting a synchronization word, a control word, and an acknowledgment word in QAM4 symbols, the method comprising transmitting the data in the same or a different type of modulation. Transmitting a transport cell, the method comprising changing a modulation of a data transport cell according to the type of home modem connected to the subscriber line in a current communication cycle. how to. 13. The method of claim 10, further comprising the step of controlling devices (home modem, office modem, and repeater) connected to the subscriber line by said control word of the downstream line signal. And how. 14. The method of claim 10, further comprising controlling the downstream repeater directly from the home modem. 15. The method of claim 10, further comprising controlling the upstream repeater directly from the office modem.