WO2001089188A1 - Emetteur-recepteur de donnees destine a transmettre et a recevoir des signaux de donnees et vocaux par l'intermediaire de lignes telephoniques - Google Patents

Emetteur-recepteur de donnees destine a transmettre et a recevoir des signaux de donnees et vocaux par l'intermediaire de lignes telephoniques Download PDF

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Publication number
WO2001089188A1
WO2001089188A1 PCT/KR2000/001261 KR0001261W WO0189188A1 WO 2001089188 A1 WO2001089188 A1 WO 2001089188A1 KR 0001261 W KR0001261 W KR 0001261W WO 0189188 A1 WO0189188 A1 WO 0189188A1
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WIPO (PCT)
Prior art keywords
data
data signal
signal
transceiver
encoded
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PCT/KR2000/001261
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English (en)
Inventor
Cheol-Hwan Kim
In-Soo Yoon
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Gigalink Co., Ltd.
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Publication date
Application filed by Gigalink Co., Ltd. filed Critical Gigalink Co., Ltd.
Priority to AU2001211771A priority Critical patent/AU2001211771A1/en
Publication of WO2001089188A1 publication Critical patent/WO2001089188A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M11/00—Telephonic communication systems specially adapted for combination with other electrical systems
    • H04M11/06—Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors
    • H04M11/062—Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors using different frequency bands for speech and other data

Definitions

  • the present invention relates to a communication equipment and, more particularly, to a communication equipment for transmitting and receiving both voice signal and LAN data through a telephone wire existing in a home or office.
  • the most common methods for high speed Internet access include the use of a DSL modem or a cable modem, which transmits and receives digital data through an existing twisted wire pair or a cable TV line, respectively.
  • the modem modulates a data signal by mapping each symbol in the signal into an amplitude, frequency, or phase information of a carrier, and transmits a modulated signal through respective transmission medium.
  • modulation schemes for mapping the symbols include a quadriphase-shift keying (QPSK) modulation, a quadrature amplitude modulation (QAM), and a discrete multi-tone (DMT) modulation.
  • QPSK quadriphase-shift keying
  • QAM quadrature amplitude modulation
  • DMT discrete multi-tone
  • a system employing the modem is disadvantageous in that the system requires a data encoding or retransmission scheme in a physical layer or a link layer, in order to facilitate an error control or correction function for reducing the effect of signal attenuation and distortion in the transmission medium, which complicates the software and hardware of the system.
  • SYSTEM discloses a system in which data signal is mixed, without the modulation, to voice signal to be transmitted through a communication medium already deployed in a home or office building and the mixed signal is separated by use of a highpass filter and a low pass filter.
  • the system may have problems that it cannot implement so high data rate, e.g. 1.5 Mbps, enough to provide high speed multimedia services and the transmission range of the system is not so long.
  • the object of the present invention is to provide a data transceiver which has a simple configuration and can reliably transmit and receive high-rate data, over a telephone wire, to and from a counterpart at a remote site far apart from the transceiver.
  • a data transceiver for achieving the above object is suitable for installing an
  • the center module is connected to an Internet server through a switching hub and the subscriber is connected to a data terminal of a subscriber. In such a condition of being connected to the respective external data equipment, the center module and the subscriber module can transmit or receive LAN data and voice signal to and from each other through the telephone wire.
  • the center module transforms a downlink LAN data signal from the switching hub so as to be suitable for channel characteristics of the telephone wire and combines a transformed downlink data signal with a downlink voice signal to transmit a combined downlink signal to the subscriber module. Also, the center module recovers an uplink LAN data signal and an uplink voice signal from a combined uplink signal to transmit the uplink LAN data signal to the switching hub. Meanwhile, the subscriber module transforms the uplink LAN data signal from the data terminal so as to be suitable for the channel characteristics and combines a transformed uplink data signal with a downlink voice signal to transmit a combined uplink signal to the subscriber module. Also, the center module recovers the downlink LAN data signal and the downlink voice signal from the combined downlink signal to transmit the downlink data signal to the data terminal.
  • the transceiver receives a first data signal and a first voice signal from a data equipment and a voice communication equipment, respectively, and combines a first encoded data signal corresponding to the first data signal with the first voice signal to transmit a combined signal to a counterpart transceiver through a telephone wire. Also the transceiver receives a second encoded data signal and a second voice signal from the counterpart transceiver through the telephone wire to provide a second data signal corresponding to the second encoded data signal and the second voice signal to the data equipment and the voice communication equipment, respectively.
  • the transceiver includes a data interface port, a voice interface port, data processing means, a band pass filter, and a low pass filter.
  • the data interface port provides an electrical interface to the data equipment for receiving the first data signal from and transmitting the second data signal to the data equipment.
  • the voice interface port provides another electrical interface to the voice communication equipment for receiving the first voice signal from and transmitting the second voice signal to the voice communication equipment.
  • the data processing means encodes the first data signal in a manner for reducing a magnitude of an accumulated DC component of the first data signal to output an encoded signal as the first encoded data signal, and decodes the second encoded data signal to recover the second data signal.
  • the band pass filter disposed between the data processing means and the telephone wire, transmits the first encoded data signal from the data processing means through the telephone wire and selectively passes the second encoded data signal of signals received through the telephone wire to the data processing means.
  • the low pass filter disposed between the voice interface port and the telephone wire, transmits the first voice signal from the voice interface port through the telephone wire and selectively passes the second voice signal of the signals received through the telephone wire to the voice interface port.
  • the transceiver includes a network adapter, an encoder, and a decoder.
  • the network adapter receives the first data signal from the data equipment and transmitting the second data signal to the data equipment according to a predetermined network protocol.
  • the encoder encodes the first data signal input through the network adapter to generate the first encoded data signal.
  • the decoder decodes the second encoded data signal received through the band pass filter to recover the second ' data signal.
  • the encoder encodes every m bits of the first data signal into an n-bit codeword according to a predetermined encoding rule, where n is larger than m, so that the magnitude of the accumulated DC component of the first encoded data signal remains small.
  • the selection of either the second or the third encoding rule is performed based on a DC component of the k-bit data.
  • the decoder decodes every n bits the second encoded data signal into an m-bit data signal according to a predetermined decoding rule reverse to the encoding rule.
  • the data processing means further includes a first buffer a packetizer, a depacketizer, and a second buffer.
  • the first buffer buffers the first data signal from the network adapter.
  • the packetizer packetizes the first data signal into a first data packet in order to transmit the first data signal in a unit of a packet including a control sequence for controlling a medium access of the transceiver.
  • the depacketizer depacketizes a second data packet received through the band pass filter and including the second data signal.
  • the second buffer buffers the second data signal to provide a buffered second data signal to the network adapter.
  • the data processing means further includes a medium access controller for controlling a medium access and allocating bands for the first and second data signal to facilitate a bidirectional data communication over the telephone wire, a retransmission controller for requesting a transmission of the second data packet to the counterpart transceiver when there exists an error in the second data packet, and an equalizer, disposed between the encoder and the band pass filter, for reducing a magnitude of a transmit level of a second bit of two consecutive data bits of the same logical levels to a reduced level.
  • the control sequence in the packet includes, at least selectively, a test vector for determining the reduced level.
  • the medium access controller controls the equalizer to transmit the test vectors in different levels, and determines the reduced level based on channel characteristic information fed back from the counterpart transceiver for the test vectors.
  • the data transceiver according to the present invention can reliably transmit and receive data of high-rate, e.g. above 1.5 Mbps, to and from a counterpart at a remote site over a telephone wire. Since transmit data is encoded in such a manner that an accumulated DC component approaches zero and the transmission level of data is adjusted to reduce the unbalance of the DC component of consecutive data bits, the data transceiver can stably communicate with the counterpart transceiver even when the counterpart transceiver is far apart from the transceiver, e.g. by more than one kilometers. Data processing in the layers higher than a physical layer and the configuration of the transceiver are simplified since the transmit data is not modulated according to a common modulation scheme.
  • the digital modem according to a preferred embodiment of the present invention is implemented by a single-chip ASIC, which further simplifies the configurations of the digital modem and the overall transceiver.
  • Such a data transceiver enables the installation of an Internet subscriber network utilizing the telephone wire already deployed in an office building, an apartment complex, a shopping area, or a hotel.
  • the Internet subscriber network according to the present invention can provide a multimedia Internet service suitable for a data transceiving pattern of each user since the time-division medium access controller adaptively allocates an uplink and a downlink channels or time slots depending on uplink and downlink traffic.
  • FIG. 1 illustrates an example of a data communication network according to the present invention
  • FIG. 2 is a circuit diagram showing the configurations of the center module and one of the subscriber modules shown in FIG. 1;
  • FIG. 3 is a block diagram of the digital modem in the center module
  • FIG. 4 is a detailed block diagram of the digital receiver shown in FIG. 3;
  • FIG. 5 is a block diagram of the digital modem in the subscriber module
  • FIG. 6 illustrates the format of a data packet, according to the present invention, transferred between the digital modems in the center module and the subscriber module;
  • FIG. 7 illustrates the concept of the 8B10B line encoding carried out the 8B10B encoder shown in FIGS. 3 and 5;
  • FIG. 8 is a flowchart showing the 8B10B line encoding process
  • FIG. 9 is a flowchart showing the 10B8B line decoding process
  • FIG. 10A illustrates transmission levels for dis-consecutive data
  • FIG. 10B illustrates transmission levels for consecutive zeroes and ones
  • FIG. IOC is a plot of the transmission reliability versus transmission levels and the distance;
  • FIGS. 10D and 10E illustrate an example of equalizing an 8B10B line-encoded bit stream;
  • FIGS. 11A and 11B are state transition diagrams showing the state transitions occurring in the time-division medium access controllers in the subscriber module and the center module, respectively;
  • FIGS. 12A and 12B are diagrams for explaining the operation of the retransmission controller shown in FIGS. 3 and 5; and
  • FIG. 13 is a diagram for explaining the operation of the transmission buffer and the receive buffer shown in FIGS. 3 and 5.
  • an example of a data communication network which is suitable for implementing an Internet subscriber network, includes a switching hub 10, a center module 20, and a plurality of subscriber subsystems 70 A through 70N.
  • the network of FIG. 1 can be installed for each apartment house, an aisle in an apartment house, or each floor or room in an office building.
  • the switching hub 10 and the center module 20 may be located in or near a main distributing frame (MDF) of the apartment house.
  • MDF main distributing frame
  • the switching hub 10 and the center module 20 may be located in or near the MDF of the building or the floor, or in the communication room of the building.
  • the switching hub 10 and the center module 20 may be installed and maintained by an Internet service provider (ISP).
  • ISP Internet service provider
  • the switching hub 10 is connected to an Internet server of the Internet service provider to exchange data traffic according to the TCP/IP protocol or the Ethernet protocol.
  • the switching hub 10 transfers downlink traffic received from the Internet, via the center module 20, to one of the subscriber subsystems 70A through 70N which is specifically dictated by an address contained in the traffic.
  • the switching hub 10 receives uplink traffic from the subscriber subsystems 70A through 70N via the center module 20 and regenerate the signal level of such a signal to transmit the regenerated signal to the Internet server.
  • the center module 20 has multiple RJ-45 and RJ-11 ports on its front panel.
  • the center module 20 is coupled to the switching hub 10 through a plurality of unshielded twisted pair (UTP) cables connected at the RJ-45 ports while being coupled to the subscriber subsystems 70A through 70N through telephone wire 50 connected at the RJ- 11 ports.
  • the center module 20 includes a thirty-seven-pin connector in its rear panel to be connected to a public services telephone network (PSTN) directly or via a private automatic branch exchange (PABX) 40.
  • PSTN public services telephone network
  • PABX private automatic branch exchange
  • the center module 20 combines a downlink data signal from the switching hub 10 and a downlink voice signal from the PSTN to transfer the combined signal to an appropriate subscriber subsystem.
  • the center module 20 divides the signal received from each of the subscriber subsystems through a respective telephone wire into an uplink data signal and an uplink voice signal to transmit the data signal to the switching hub 10 and the voice signal to an exchange of the
  • the subscriber subsystem 70A includes a wall outlet 72A and a subscriber module 74A to which subscriber premises, i.e., a data terminal 76 A and/or a telephone 78 A may be coupled.
  • the wall outlet 72 A which may be installed on the wall of the house similarly to a conventional phone outlet, allows the user to couple the data terminal 76A and the telephone 78A to the telephone wire through the subscriber module 74 A.
  • the subscriber module 74 A has at least one RJ-45 and RJ-11 ports for being connected to the data terminal 76A and the telephone 78A, respectively.
  • the subscriber module 74A When being stuck onto the wall outlet 72A, the subscriber module 74A combines the uplink data signal from the data terminal 76A and the voice signal from the telephone 78A and divides a received downlink signal into a downlink data signal and a downlink voice signal to provide such signals to the data terminal 76A and the telephone 78A, respectively.
  • the configurations of the other subscriber subsystems 70B through 70N may be similar to that of the subsystem 70 A.
  • FIG. 2 is a circuit diagram illustrating the configurations of the center module 20 and the subscriber module, e.g. 74 A, shown in FIG. 1.
  • the center module 20 includes a switching hub interface port 30, a digital modem 32, a first band pass filter (BPF) 34, a first low pass filter (LPF) 36, and a telephone network interface port 38.
  • the switching hub interface port 30, which is an RJ-45 port, is connected to the switching hub 10 shown in FIG. 1 through transmission media such as a twisted pair or a coaxial cable.
  • the digital modem 32 transforms the downlink data from the switching hub 10 so as to be suitable for the transmission through the telephone wire 50 and transmits the transformed data to the subscriber module 74A. Also, the digital modem 32 restores the uplink data from the data signal received from the subscriber module 74 A and transmits the restored data to the switching hub 10.
  • the first BPF 34 selectively passes the data signal, of the signals received from the subscriber module 74 A, to the digital modem 32.
  • the first LPF 36 selectively passes the voice signal, of the signals received from the subscriber module 74 A, to the telephone network interface 38.
  • the telephone network interface port 38 which is an RJ-11 port, is connected to the PSTN switch through a twisted pair.
  • the subscriber module 74A includes a data terminal interface port 80, a digital modem 82, a second BPF 84, a first LPF 86, and a telephone interface port 88.
  • the switching hub interface port 30, which is the RJ-45 port, is connected to the switching hub 10 shown in FIG. 1.
  • the digital modem 82 transforms the downlink data from the data terminal 76A so as to be suitable for the transmission through the telephone wire 50 and transmits the transformed data to the center module 20.
  • the digital modem 32 restores the downlink data from the data signal received from the center module 20 and transmits the restored downlink data to the data terminal 74A.
  • the second BPF 84 selectively passes the data signal, of the signals received from the center module 20, to the digital modem 82.
  • the second LPF 86 selectively passes the voice signal, of the signals received from the center module 20, to the telephone interface 88.
  • the telephone network interface port 88 which is the RJ-11 port, is connected to the telephone 78 A shown in FIG. 1.
  • the wall outlet 72A provides the subscriber module 74A with a connection to the telephone wire 50 but is transparent for the data transmission in the preferred embodiment.
  • the downlink data from the switching hub 10 is transformed by the digital modem 32 so as to be suitable for the transmission through the telephone wire 50, and then combined with the voice signal to be transmitted to the subscriber module 74A.
  • the data signal having a higher frequency band is selected by the second BPF 84 and restored by the digital modem 82 to be provided to the data terminal 76A while the voice signal having a lower frequency band is selected by the second LPF 86 and provided to the telephone 78A.
  • the uplink data from the data terminal 76A is transformed by the digital modem 82 so as to be suitable for the transmission through the telephone wire 50, and then combined with the voice signal to be transmitted to the center module 20.
  • FIG. 3 illustrates the digital modem 32 in the center module 20 in detail.
  • the digital modem 32 includes a network adapter 100, a transmission buffer 120, a receive buffer 130, a data transfer controller 140, a transmitting unit 150, and a receiving unit 160.
  • such a digital modem is implemented by a single-chip ASIC.
  • the network adapter 100 includes an Ethernet controller 102 for transmitting and receiving data to and from the switching hub 10 in accordance with an Ethernet protocol and carrying out a Medium Access Control (MAC) associated with the operation, and a network interface 104 for suitably interfacing the Ethernet controller 102 to a physical medium connecting the center module 20 to the switching hub 10.
  • the Ethernet controller 102 transmits and receives data to and from the switching hub 10 while performing the Carrier Sense Multiple Access with Collision Detection (CSMA/CD) protocol defined in JJEEE802.3x standards, so as to prevent a data collision due to a collision.
  • CSMA/CD Carrier Sense Multiple Access with Collision Detection
  • the network interface 104 includes at least one of available interfaces, e.g., a Media Independent Interface (Mil), a twisted-pair transceiver media attachment unit (MAU), a General Purpose Serial Interface (GPSI) , an Attachment Unit Interface (AUI) 24, and an External Address Detection Interface (EADI) 23 c, so as to enable the communication between the switching hub 10 and the center module 20.
  • available interfaces e.g., a Media Independent Interface (Mil), a twisted-pair transceiver media attachment unit (MAU), a General Purpose Serial Interface (GPSI) , an Attachment Unit Interface (AUI) 24, and an External Address Detection Interface (EADI) 23 c, so as to enable the communication between the switching hub 10 and the center module 20.
  • the transmission buffer 120 temporarily stores and buffers the downlink data received from the switching hub 10 and then depacketized by the Ethernet controller 102 to facilitate the data reception from the switching hub 10 and the data transmission to the subscriber terminal 76 A.
  • the receive buffer 120 temporarily stores and buffers the uplink data from the subscriber terminal 76A to facilitate the data reception from the subscriber terminal 76 A and the data transmission to the switching hub 10.
  • the transmitting unit 150 includes an 8B10B encoder 152, an equalizer 154, and an amplifier 156.
  • the 8B10B encoder 152 encodes the downlink data in a way in which a DC component in a downlink data signal is removed or reduced, so that the interference between the data signal and the telephone voice signal is minimized during the transmission through the telephone wire 50.
  • the equalizer 154 changes the level of the downlink data signal according to the characteristics and length of the telephone wire 50 to enhance a transmission reliability of the system. The detailed description of the operations of the 8B10B encoder 152 and the equalizer 154 are provided farther below.
  • the amplifier 156 amplifies an equalized signal from the equalizer 154 to the telephone wire 50.
  • the receiving unit 160 includes a digital receiver 162 for detecting symbols from a received uplink signal, and a 10B8B decoder 164 for decoding detected symbols to recover uplink data.
  • the digital receiver 162 further includes an integrator 180, a digital sampler 182, a symbol detector 184, and a phase controller 186.
  • the integrator 180 integrates the received uplink signal so that the received signal is sampled while the effect of noise introduced in the signal over the telephone wire 50 is minimized.
  • the sampler 182 carries out sampling of the integrated signal level, and the symbol detector 184 detects symbols from sampled signal levels.
  • the phase controller 186 determines timings for sampling from the sampled signal levels so that the detected symbols are precisely synchronized.
  • the data transfer controller 140 includes a time-division medium access controller 142, a retransmission controller 144, a packetizer 146, and a depacketizer 148.
  • the time- division medium access controller 142 is responsible for sending and receiving Medium access control frames, to and from a counterpart in the digital modem 82 in the subscriber module 74A, for handling flow control so as to allocate uplink and downlink bands and facilitate bidirectional data communications.
  • the retransmission controller 144 enables the retransmission of data when a packet error happens over the telephone wire 50.
  • the retransmission controller 144 sends a retransmission request when the packet error happens during the receipt of an uplink data packet, and enables a downlink data packet to be retransmitted from the transmission buffer 120 through the transmission unit 150 when receiving the retransmission request from the subscriber module 74A.
  • the packetizer 146 packetizes the downlink data of Ethernet format in the transmission buffer 120 by adding a preamble and several delimiters, encapsulating the Ethernet packet .
  • the depacketizer 148 depacketizes the uplink data packet stored in the receive buffer 130, by removing the preamble and delimiters therein, to restore the uplink data of the Ethernet format.
  • FIG. 5 illustrates the digital modem 82 in the subscriber module 74A in detail.
  • the digital modem 82 in the subscriber module 74A has the same configuration as its counterpart in the center module 20 shown in FIG. 3.
  • the digital modem 82 operates in a manner similar to the digital modem 32 except that: (1) the modem 32 transmits the downlink data packet and receives the uplink data packet while the modem 82 transmits the uplink data packet and receives the downlink data packet, and (2) the modem 32 is coupled to the switching hub 32 but the modem 82 is coupled to the subscriber module 74 A.
  • the data packet includes a preamble 200 for synchronizing the phase controller 186 of a receiving party, a Start-of -Frame delimiter (SOF) 202 for indicating the start of a new packet, a control sequence 204 for the medium access control, client data 206 which is the encoded uplink or downlink data, a cyclic redundancy check (CRC) value 208 for detecting or correcting errors, and a End-of-Frame delimiter (EOF) 210.
  • SOF Start-of -Frame delimiter
  • CRC cyclic redundancy check
  • EEF End-of-Frame delimiter
  • the preamble 200 is a repetitive pattern of a certain bit stream and is used to synchronize the phase controller 186 of the receiving station.
  • the control sequence 204 contains information on the data buffers 120 and/or 130 of the transmitting and/or receiving stations, information indicating transmission errors, and information indicating the allowance of data transmission.
  • the data signal contains less low-frequency components below 4 kHz.
  • the digital modems 32 reduces the low-frequency components by encoding data according to an 8B10B line encoding scheme which is a combination of a 5B6B and 3B4B encoding schemes.
  • FIG. 7 illustrates the concept of the 8B10B line encoding carried out by the 8B10B encoder 152 shown in FIGS. 3 and 5.
  • the 8B10B encoder 152 encodes only the client data except the preamble and delimiters in the data packet shown in FIG. 6. Every eight-bit of data is divided into the most significant 5 bits and the least significant 3 bits, which are encoded into a codeword of 6 bits and 4 bits, respectively.
  • the most significant 5 bits are encoded according to an encoding table I and the least significant 3 bits are encoded according to either an encoding table IIA or JIB.
  • Six-bit codewords in the encoding table I are prepared in such a manner that DC component of each of the codeword is minimized.
  • Each of the four-bit codewords in the encoding table IIA is prepared so as to have slightly negative DC component while each of the four-bit codewords in the encoding table LIB is prepared so as to have slightly positive DC component.
  • one of the encoding tables IIA and IIB is selected so that an accumulated DC component (DQ) approaches zero. That is, the least significant 3 bits are encoded according to the encoding table IIA when the accumulated DC component (DQ) is positive but are encoded according to the encoding table IJJB when the accumulated DC component (DC;) is negative. Accordingly, the accumulated DC component (DQ) continuously approaches zero.
  • step 250 eight-bit data is divided into the most significant 5 bits and the least significant 3 bits (step 250), and the most significant 5 bits are encoded into a six-bit codeword according to the encoding table I (step 252).
  • the DC component (DC) of the six-bit codeword is calculated in step 254, and the calculated DC component (DC) is added to an accumulated DC component unto a last data transmission (DQ.,) to calculate the accumulated DC component unto a current data transmission (DC;) in step 256.
  • step 258 it is determined whether the accumulated DC component (DQ) is negative or not (step 258).
  • the least significant 3 bits are encoded into a four-bit codeword (4B+) according to the table LTA (step 260). If the accumulated DC component (DQ) is negative in the step 258, however, the least significant 3 bits are encoded into a four-bit codeword (b-) according to the table JJB (step 262). Finally, the six-bit codeword (6B) and the four- bit codeword(4B+ or 4B-) are concatenated to generate a encoded data often bits in step 264.
  • the decoding process carried out by the 10B8B decoder 164 is as follows.
  • a received data often bits is divided into the most significant 6 bits and the least significant 4 bits (step 270), and the most significant 6 bits are decoded into a five-bit data according to the table I (step 272).
  • the DC component (DC) of the most significant 6 bits of the received data is calculated in step 274, and the calculated DC component (DC) is added to an accumulated DC component upto a last data reception (DCi. j ) to calculate the accumulated DC component upto a current data reception (DQ) in step 276. Subsequently, it is determined whether the accumulated DC component (DQ) is negative or not (step 278).
  • the least significant 4 bits are decoded according to the table IIA (step 280). If the accumulated DC component (DQ) is negative in the step 278, however, the least significant 4 bits are decoded according to the table IIB (step 282). Finally, the five-bit data and the three-bit data are concatenated to restore an original data of eight bits in step 284. Next, the operation of the equalizer 154 in the transmitting unit 150 shown in
  • FIGS. 3 and 5 will be described with reference to FIGS. 10A through 10D.
  • transmission characteristics of the telephone wire having an effect on an error rate of received data, varies depending on the medium properties of the wire, a wiring condition, and a transmission distance.
  • the error rate of received data is influenced by a balance level of the DC component.
  • An unbalance of the DC component is increased when a plurality of data bits of the same sign are transmitted consecutively.
  • the equalizer 154 reduces the unbalance of the DC component by adjusting the transmission level of data when data bits of the same sign are transmitted consecutively.
  • the equalizer 154 adaptively adjusts the transmission level according to the transmission characteristics of the telephone wire so as to ensure the stable data transmission.
  • the equalizer 154 transmits the data bit data in a level of V peak or - Vpea k wnen tne ata °ft * s "* " or "0" > respectively.
  • the equalizer 154 transmits the data bit data in a level of V; or -N when the data bit is "1 " or "0", respectively.
  • the magnitude of the level (N) used for transmitting consecutive zeros or ones is smaller than the magnitude of the level (V peak ) for transmitting consecutive zeros or ones, and thus the DC component of the signal carrying consecutive zeros or ones is reduced.
  • the transmission reliability is a function of the transmission level and distance. Accordingly, it is preferable that the magnitude of the level (N) for transmitting consecutive data is determined in consideration of the channel characteristics as well as the transmission distance. Since the equalizer 154 of a transmitting party does not know the channel characteristics nor the transmission distance, the time-division medium access controller 142 of the transmitting party sends, to a receiving party through the equalizer 154, a plurality of test vectors having levels different from one another. The time-division medium access controller 142 of the receiving party determines the channel characteristics on the basis of received test vectors and feeds back the channel characteristics information. Thus, the transmitting party can determine the level (N) optimized to the transmission channel.
  • FIGS. 10E illustrates an example of equalizing an 8B10B line-encoded bit stream of FIG. 10D.
  • FIGS. I IA and IIB are state transition diagrams showing the state transitions occurring in the time-division medium access controllers 142 in the subscriber module 74A and the center module 20, respectively. Referring to FIG.
  • the subscriber module 74A exists in any of five possible states: a channel search state S10, a stand-by state S12, a receiving state S14, a control packet transmission state S16, and a data packet transmission state SI 8.
  • the time-division medium access controller 142 of the subscriber module 74A controls the transmission unit 150 and the receiving unit 170 to alternate test vector transmissions and acknowledgment packet receptions while changing the state of the equalizer 154, and determines an equalizer condition suitable for the channel condition according to a number of acknowledgment packets.
  • the subscriber module 74A moves into a link established condition after sending a link establishing packet to the center module 20 (step 300).
  • the subscriber module 74 A In case of failure of the channel search, the subscriber module 74 A will transition to the stand-by state S12 (step 302). ⁇ When the stand-by time period expires, the subscriber module 74 A will transition back to the channel search state S10 to search the center module 20 (304).
  • the center module 20 exists in any of five possible states: a stand-by state S20, a acknowledgment packet transmission state S22, a receiving state S24, a control packet transmission state S26, and a data packet transmission state S28. In the condition that the link is not established, the center module 20 waits for the test vector packet from the subscriber module 74A in the stand-by state S20.
  • the center module Upon receiving the test vector packet properly, the center module moves into the acknowledgment packet transmission state S22 in step 350 to the acknowledgment packet to the subscriber module 74A. After the subscriber module 74A checks the channel condition and sends the channel establishment packet, the center module 20 moves into the link established condition after setting up the equalizer 154 of itself (step 352). In case that the channel establishment packet is not received for a certain time period, however, the center module 20 will transition back to the stand-by state S20 (step 354).
  • the subscriber module 74A and the center module 20 moves around the receiving state S14 or S24, the control packet transmission state S16 or S26, and the data packet transmission state S18 or S28.
  • the subscriber module 74A moves into the data packet transmission state SI 8 or the control packet transmission state SI 6, depending on the existence of uplink data to be transmitted, after receiving the EOF delimiter of the downlink packet (step 306 or 310).
  • the subscriber module 74 A moves into the data packet transmission state SI 8 or into the control packet transmission state S16 after a certain time period expires (step 306 or 310).
  • the subscriber module 74A transmits an uplink data packet to the center module 20 in the data packet transmission state SI 8 and then transitions back to the receiving state S14 (step 308).
  • the subscriber module 74A transmits an uplink control packet to the center module 20 in the control packet transmission state S16 and then transitions back to the receiving state S14 (step 312).
  • packet errors are excessive or a certain packet waiting time expires, the subscriber module 74A transitions back to the stand-by state S12 (step 314).
  • the center module 20 moves into the data packet transmission state S28 or the control packet transmission state S26, depending on the existence of down data to be transmitted, after receiving the EOF delimiter of the uplink packet (step 356 or 360). That is, the center module 20 moves into the data packet transmission state S28 to transmit a downlink data packet to the subscriber module 74A in case that there is downlink data to be transmitted while moving into the control packet transmission state S26 to transmit a downlink control packet to the subscriber module 74 A.
  • the center module 20 transitions back to the receiving state S24 to wait for another uplink packet from the subscriber module 74 A (step 358 or 362).
  • the center module 20 transitions back to the stand-by state S20 (step 364).
  • FIGS. 12A and 12B are diagrams for explaining the operation of the retransmission controller 144 shown in FIGS. 3 and 5.
  • the retransmission controller 144 prevents an error in the data packet due to an impulse noise and signal leakage in the telephone wire, so that a possible error in the telephone wire is propagated in an upper layer and multimedia data is reliably transmitted to the receiving party.
  • the center module 20 or the subscriber module 74A waits for the acknowledgment packet from the counterpart, i.e. receiving party.
  • the acknowledgment packet from the receiving party includes an acknowledgment bit ACK(i) indicating whether the i-th packet "DATA PACKET(i)" was received property.
  • the transmitting party transmits a next packet "DATAPACKET(i+l)" when the acknowledgment bit ACK(i) has a value of "1 ", but retransmits the packet "DATA PACKET(i+l)" already transmitted when the acknowledgment bit ACK(i) has a value of "0" or the acknowledgment packet is not received.
  • FIG. 13 is a diagram for explaining the operation of the transmission buffer 120 and the receive buffer 130 of the shown in FIGS. 3 and 5.
  • the transmission buffer 120 buffers the data received from the center module 20 or the subscriber module 74 A through the network interface 104 and the Ethernet controller 102 while the receive buffer 130 buffers the data to be transmitted to the center module 20 or the subscriber module 74 A through the Ethernet controller 102 and the network interface 104.
  • the network interface 104 which may be equipped with at least one of the several interfaces, preferably is configured to support the general Ethernet standards such as lOBase-T and 100Base-T.
  • Data transmitting or receiving rates may differ between the digital modem 32 or 82 and the switching hub 10 or the subscriber terminal 76 A since the data rate in Ethernet is 10 Mbps or 100 Mbps while the digital modems 32 and 82 operates in higher speed.
  • the Ethernet controller 102 performs traffic controls by using "back-pressure" or "PAUSE" packet defined in the LEEE 802.3.
  • each of the digital modems 32 and 82 may include a non- volatile memory, such as an EEPROM or a flash memory, for storing program codes for operating the time-division medium access controller 142 and the retransmission controller 144.
  • the digital modems 32 and 82 may additionally include a volatile memory such as a DRAM.
  • the DRAM can facilitate the packetization and depacketization process and store the control sequence 204 obtained from the received packet so that the time-division medium access controller 142 or the retransmission controller 144 refers to the sequence.
  • each of the digital modems 32 may include a main controller for controlling overall operations of the modem.
  • the encoding may be carried out for all the packet, alternatively.
  • the 8B10B encoding may be generalized to an mBnB encoding.
  • the 8B10B encoding may be consists of two 4B5B encodings or one 6B7B encoding and one 2B3B encoding as well.
  • the encoding may be followed by the packetization in another alternative embodiment even though the encoding is preceded by the packetization.
  • the packetizer 146 packetizes the data in the transmit buffer 120 for the simplicity of the description. However, the packetizer 146 actually packetizes the data input to or output by the transmit buffer 120 in the preferred embodiment of the present invention. In respective one of such cases, the depacketizer 148 depacketizes the data output by or input to the receive buffer 130, respectively.
  • the packetizer 146 may be disposed between the encoder 152 and the equalizer 154 to packetize the encoded data signal, and the depacketizer 148 may be disposed between the digital receiver 162 and the decoder 164 accordingly.
  • the filter for selectively passing the data signal in the digital modem 32 or 82 is referred to as a "band pass filter", a high pass filter might be employed as well. Therefore, in this specification including appended claims, the terminology, the "band pass filter”, should be understood to include the “high pass filter”.
  • the communications between the switching hub 10 and the center module 20 and between the subscriber module 74A and the data terminal 76A is performed according to the Ethernet protocol, another network protocol may be used as well.
  • either the encoder 152 or the equalizer 154 may be omitted from the digital modems 32 and 82 in an alternative of the preferred embodiment. In case that the encoder 152 is omitted, the decoder 164 should be omitted simultaneously.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Data Exchanges In Wide-Area Networks (AREA)
  • Telephonic Communication Services (AREA)

Abstract

L'invention concerne un émetteur-récepteur de données de configuration simple, pouvant transmettre et recevoir de manière fiable des données à débit élevé vers et en provenance d'un émetteur-récepteur associé, situé à distance du premier émetteur-récepteur, par l'intermédiaire d'un câble téléphonique. Ledit émetteur-récepteur code un premier signal de données provenant d'un équipement de données, en un premier signal de données codé transmis vers un émetteur-récepteur associé par l'intermédiaire d'un câble téléphonique (50), et reçoit un deuxième signal de données codé de l'émetteur-récepteur associé par l'intermédiaire du câble téléphonique (50) afin de fournir à l'équipement de données un deuxième signal de données correspondant au deuxième signal de données codé. Un codeur 8B10B (152) code le premier signal de données de manière à réduire l'importance d'un composant à courant continu accumulé du premier signal de données. Un dispositif de mise en paquets (146) encapsule la premier signal de données ayant un format Ethernet. Un égaliseur (154) égalise un signal encapsulé afin de réduire l'importance d'un niveau de transmission d'un deuxième bit de deux bits de données consécutifs du même niveau logiciel. Une commande d'accès au support (142) commande l'accès au support afin de simplifier la communication de données bidirectionnelle au travers du câble téléphonique (50).
PCT/KR2000/001261 2000-05-18 2000-11-04 Emetteur-recepteur de donnees destine a transmettre et a recevoir des signaux de donnees et vocaux par l'intermediaire de lignes telephoniques WO2001089188A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2001211771A AU2001211771A1 (en) 2000-05-18 2000-11-04 Data transceiver for transmitting and receiving data and voice signal over telephone line

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
KR20000026830 2000-05-18
KR2000/26830 2000-05-18
KR2000/56334 2000-09-26
KR1020000056334A KR100329713B1 (ko) 2000-05-18 2000-09-26 전화선을 통해 음성과 데이터를 송수신하는 데이터 송수신기

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WO2001089188A1 true WO2001089188A1 (fr) 2001-11-22

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JP (1) JP2001333217A (fr)
KR (1) KR100329713B1 (fr)
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EP1343279A1 (fr) * 2002-03-05 2003-09-10 Nokia Corporation Synchronisation dans un système de communication
US11575406B1 (en) * 2019-07-12 2023-02-07 Cable Television Laboratories, Inc. Systems and methods for broadband signal equalization

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KR20030016873A (ko) * 2001-08-22 2003-03-03 이종선 패널티 킥 게임기
US7068711B2 (en) * 2002-03-13 2006-06-27 Agere Systems Inc. Multi-function equalizer arrangement
WO2016129088A1 (fr) * 2015-02-12 2016-08-18 日立マクセル株式会社 Dispositif d'émission, dispositif de réception, et système d'émission et de réception

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JPH04188997A (ja) * 1990-11-21 1992-07-07 Smk Corp 信号伝送装置
JPH0832713A (ja) * 1994-07-12 1996-02-02 Nec Eng Ltd コードレス電話機
JPH08204840A (ja) * 1995-01-27 1996-08-09 Mitsubishi Electric Corp パーソナル通信装置
JPH08256225A (ja) * 1995-03-17 1996-10-01 Hitachi Denshi Ltd 音声信号とモデム信号の同時伝送方式における送信装置および受信装置

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Publication number Priority date Publication date Assignee Title
JPH04188997A (ja) * 1990-11-21 1992-07-07 Smk Corp 信号伝送装置
JPH0832713A (ja) * 1994-07-12 1996-02-02 Nec Eng Ltd コードレス電話機
JPH08204840A (ja) * 1995-01-27 1996-08-09 Mitsubishi Electric Corp パーソナル通信装置
JPH08256225A (ja) * 1995-03-17 1996-10-01 Hitachi Denshi Ltd 音声信号とモデム信号の同時伝送方式における送信装置および受信装置

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Publication number Priority date Publication date Assignee Title
EP1343279A1 (fr) * 2002-03-05 2003-09-10 Nokia Corporation Synchronisation dans un système de communication
US7324549B2 (en) 2002-03-05 2008-01-29 Nokia Corporation Synchronisation communication systems
CN100396047C (zh) * 2002-03-05 2008-06-18 诺基亚公司 经由总线同步数据通信的方法
EP1865667A3 (fr) * 2002-03-05 2008-10-29 Nokia Siemens Networks Oy Synchronisation dans des systèmes de communication
US11575406B1 (en) * 2019-07-12 2023-02-07 Cable Television Laboratories, Inc. Systems and methods for broadband signal equalization

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JP2001333217A (ja) 2001-11-30
KR100329713B1 (ko) 2002-03-21
AU2001211771A1 (en) 2001-11-26
KR20010016014A (ko) 2001-03-05

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