JP2001186215A - Modem device, communication system and its authentication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a modem device, a communication system and its authentication method which use a CATV line as the Internet access network. SOLUTION: This communication system has CMTSs 1 to 3, a MIX, E/O, DIS part 4 and an NMS(network monitoring system) 5 on a CATV station side and a NODES 11 to 16 and CMs(cable modem) 21 to 26 on a subscriber line side. According to the above configuration, because the CMs(cable modem) 21 to 26 can decide whether to use a down carrier simply by receiving and checking a down message, the CMs 21 to 26 can smoothly perform authentication processing even in such a system configuration where a plurality of carriers are generated on the same down trunk. Then, it is possible to realize fast data communication processing in the case of accessing the Internet, etc., from the personal computer (hereafter called a personal computer) of a subscriber terminal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a modem device, a communication system and an authentication method thereof, and more particularly to a modem for use as an access network utilizing a data communication service such as the Internet using a CATV (cable television) line network. The present invention relates to an apparatus, a communication system, and an authentication method thereof.

[0002]

2. Description of the Related Art Conventionally, cable television lines (hereinafter referred to as CA
A TV line) transmits an information signal only in a downlink direction from a base station (head center) to each subscriber terminal device, and is transmitted from a subscriber terminal side in an uplink direction. Was not done.

[0003] At present, bidirectional CATV is known as a form in which a signal not only in the downlink direction but also in the uplink direction can be transmitted using a frequency band not used for a channel of a television. As described above, a bidirectional data transmission method using a CATV line has been developed. For example, as a request response type moving image search service that provides a desired program (movie, communication karaoke, etc.) in response to a request from a viewer. Is applied to data communication services such as VOD (Video on Demand).

[0004] Since the CATV line has a larger data transmission capacity than the telephone line, the CATV line has a higher capacity.
A network is constructed using a line. For example, at present, a PC online service that allows a subscriber such as the Internet to access at high speed has been developed.

[0005] In the PC online service, an interface corresponding to both a CATV line and a network line called a cable modem device is installed in a subscriber's house, and a personal computer serving as a terminal device is connected via this interface (cable modem device). And so on. For example, an Ethernet system compatible with IEEE802.3 is applied between such a cable modem device and a personal computer to achieve 10M.
A transmission capacity of bps can be easily realized.

[0006] In the CATV line as described above, an asymmetric type is used in which a low frequency band, which is rarely used in CATV broadcasting, is used for uplink data communication and a high frequency band is used for downlink data communication. Generally enables two-way communication.

[0007] The CATV line adopts a broadband system, creates a plurality of channels for the same physical transmission medium by using carriers of different frequencies, and uses them for channels for uplink data communication from terminal devices of different types. To compensate for the fact that the data transmission speed is relatively low speed and small capacity,
The V line has a larger data transmission capacity than the telephone line. In other words, the CATV line configures a transmission path by one downlink data communication channel having a high data rate and a large capacity and a plurality of uplink data communication channels having a low data rate and a small capacity. This enables high-speed data communication over the entire line.

Therefore, by constructing a network using such a CATV line, a high-speed data communication process can be performed, for example, when accessing the Internet or the like from a personal computer (hereinafter referred to as a personal computer) which is a subscriber terminal device. Becomes possible.

For example, if a television signal is to be transmitted as an analog signal as it is, a frequency band of 6 MHz is required for one channel, and the maximum frequency reaches 550 MHz in a 76-channel system used in the United States and the like. When the number of channels is increased in this manner, the frequency band used is also increased in proportion to the number of channels. Therefore, a coaxial cable formed of copper wire is not suitable for long-distance transmission due to a large attenuation factor.

Therefore, by using an optical fiber cable capable of transmitting signals in a wide frequency band instead of a coaxial cable, it is possible to use a frequency up to about 1 GHz.

However, a system in which a base station converts an electric signal into an optical signal and transmits the signal, and a receiving station includes a photoelectric conversion device for converting the transmitted optical signal into an original electric signal. In consideration of the configuration, the cost of the photoelectric conversion device is high, so that there is a problem that it is uneconomical to directly distribute to each subscriber terminal by an optical fiber cable.

[0012] Therefore, after transmission from the base station (head center) to the middle through an optical fiber cable, an optical signal is converted into an electric signal, and a distribution distance section (the last 1-2 km) to each subscriber terminal is coaxial. With a configuration in which distribution is performed via a cable, one photoelectric conversion device can be shared by hundreds of homes. This method is called an “optical / coaxial hybrid (HFC) method”.

[0013]

However, in a conventional communication system using a CATV line, the CMT
Downlink control message (MMM: MA) from S (Cable Modem Termination System)
C MANAGEMENT MESSAGE) does not include the upstream transmission path information of the CM (cable modem) belonging to the CMTS.

[0014] With this, when a system configuration is adopted in which a plurality of carriers are accommodated in a downlink trunk in a CATV line, the CM performs an authentication operation (ranging process) for each carrier every time a downlink carrier is detected. ) Will have to try.

The ranging process means that each CM adjusts a physical layer parameter such as an uplink level and a timing with respect to each of a plurality of multiplexed carriers from the CMTS, and determines a carrier to which the CM belongs. This is a process for determining whether or not.

For example, a carrier assigned to an arbitrary CM is F40, and a carrier transmitted from the CMTS is F40.
If a plurality of carriers from 1 to F50 are frequency-multiplexed, the CM performs ranging processing at least from F1 to F2, F3,.
For each carrier up to 39, an authentication operation must be performed to determine whether or not the carrier is in charge of the carrier, and there is a problem that this authentication operation takes time.

Further, as described above, there is a problem that the communication processing speed in the entire communication system is reduced due to the time required for the authentication operation in each CM.

Further, when a plurality of carriers exist on the same downstream trunk line, a smooth authentication operation cannot be performed, and there is a problem that communication of another CM may be obstructed.

For example, a communication network using a CATV line overseas has a topology in which the downstream trunk line is generally common (broadcast type and the number of routes is small) and the upstream trunk line is individual (the number of routes is large). In this case, a configuration in which a plurality of carriers are set up on one downstream trunk line is unavoidable, and there is an urgent need to solve the above problem.

The present invention has been made in view of the above-described problems. Even when a plurality of carriers are generated on the same downstream trunk, the time required for the authentication operation by the modem can be reduced, and other problems can be solved. It is an object of the present invention to provide a modem device, a communication system, and an authentication method thereof that reduce the influence of a modem on communication.

[0021]

In order to solve the above-mentioned problem, the invention according to claim 1 is characterized in that it is determined whether or not to receive a downlink carrier based on transmission path information.

According to a second aspect of the present invention, in the first aspect, the transmission path information is included in a downlink carrier from the base station.

According to a third aspect of the present invention, in the second aspect of the present invention, the transmission path information is uplink transmission path information from a modem device to a base station.

The invention according to claim 4 is the invention according to claim 2 or 3.
In the invention described above, the modem device stores uplink transmission path information for a base station.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the modem device includes the uplink transmission line information contained in the downlink carrier from the base station and the uplink transmission line information held by the modem device. It is characterized in that it is determined whether or not to receive a downlink carrier based on the result of the collation.

According to a sixth aspect of the present invention, in the second aspect of the present invention, the modem device includes: a search means for searching for a downlink carrier from the base station; When present, a matching unit for checking the uplink transmission line information included in the downlink carrier with the uplink transmission line information held in the modem device, and whether to receive the downlink carrier based on the matching result by the matching unit. Determining means for determining whether or not the determination is made.

According to a seventh aspect of the present invention, in the sixth aspect, the search means searches for a downlink carrier from the base station while changing the frequency.

[0028] According to an eighth aspect of the present invention, in the first aspect of the present invention, the modem device comprises:
It is a cable modem device connected to an ATV (cable television) line.

According to a ninth aspect of the present invention, in the eighth aspect of the present invention, the modem device desirably includes a filter for filtering an input signal from the CATV line and an input signal filtered by the filter. Tuning means for tuning to the carrier frequency, demodulating means for demodulating an input signal tuned by the tuning means, MAC processing means for processing MAC information included in the input signal demodulated by the demodulating means, and MAC processing means. Interface means for outputting user data to the terminal device based on the processed MAC information; storage means for temporarily storing user data input via the interface means; A modulating means for modulating a signal to which the MAC information is added by the processing means; Converting means for signal converted to a predetermined frequency and outputs that are, and control means for controlling each section, signal converted to a predetermined frequency by the conversion means,
After being filtered by the filter means, the data is output to the CATV line.

According to a tenth aspect of the present invention, in the ninth aspect of the present invention, the demodulation means performs the demodulation by the QAM method.

According to an eleventh aspect of the present invention, in the ninth or tenth aspect of the present invention, the modulating means modulates by a 16 QAM system or a QPSK system.

According to a twelfth aspect of the present invention, there is provided a modem device for determining whether to receive a downlink carrier based on transmission path information.

According to a thirteenth aspect, in the twelfth aspect, the transmission path information is included in a downlink carrier from the base station.

[0034] According to a fourteenth aspect of the present invention, in the thirteenth aspect, the transmission path information is uplink transmission path information from the modem device to the base station.

According to a fifteenth aspect of the present invention, in the thirteenth or fourteenth aspect, the modem device holds uplink transmission path information for the base station.

According to a sixteenth aspect of the present invention, in the invention according to the fifteenth aspect, the modem device includes the uplink transmission line information contained in the downlink carrier from the base station and the uplink transmission line information held by the modem device. It is characterized in that it is determined whether or not to receive a downlink carrier based on the result of the collation.

According to a seventeenth aspect of the present invention, in the invention according to any one of the thirteenth to sixteenth aspects, the modem device comprises: a search means for searching for a downlink carrier from the base station; If present,
Collating means for collating the uplink transmission path information contained in the downlink carrier with the uplink transmission path information held in the modem device, and judging whether to receive the downlink carrier based on the collation result by the collation means Determining means.

The invention according to claim 18 is the invention according to claim 17, wherein the search means searches for a downlink carrier from the base station while changing the frequency.

According to a nineteenth aspect, in the invention according to any one of the twelfth to eighteenth aspects, the communication system is configured to include management means for managing a state of the communication system. Features.

According to a twentieth aspect of the present invention, in the nineteenth aspect of the present invention, when a new modem device is added to the communication system, the management means is based on an IP address issue request from the modem device. And issues an IP address.

According to a twenty-first aspect of the present invention, in any one of the twelfth to twentieth aspects, the communication system performs communication via a CATV (cable television) line.

According to a twenty-second aspect of the present invention, in the twenty-first aspect, the modem device is a cable modem device (C) connected to a CATV (cable television) line.
M).

According to a twenty-third aspect of the present invention, in the twenty-second aspect of the present invention, the cable modem device (CM) comprises a CA
Filter means for filtering an input signal from a TV line, tuning means for tuning the input signal filtered by the filter means to a desired carrier frequency, and demodulation means for demodulating the input signal tuned by the tuning means When,
MAC processing means for processing MAC information included in the input signal demodulated by the demodulation means; interface means for outputting user data to the terminal device based on the MAC information processed by the MAC processing means; Storage means for temporarily storing the user data input via the storage means, modulation means for modulating a signal obtained by adding MAC information by MAC processing means to the user data stored by the storage means, and a signal modulated by the modulation means to a predetermined value. And a control unit for controlling each unit. The signal converted to a predetermined frequency by the conversion unit is filtered by the filter unit and output to the CATV line. It is characterized by being performed.

According to a twenty-fourth aspect of the present invention, in the twenty-third aspect of the present invention, the demodulation means demodulates by a QAM system.

According to a twenty-fifth aspect of the present invention, in the twenty-third aspect or the twenty-fourth aspect of the present invention, the modulating means modulates by a 16QAM system or a QPSK system.

According to a twenty-sixth aspect of the present invention, in a communication system having an asymmetric transmission line, a downlink carrier from a base station includes information on an upstream transmission line from a modem device belonging to the base station.

According to a twenty-seventh aspect of the present invention, in the twenty-sixth aspect, the modem device holds information on an uplink transmission path from the modem device to the base station.

According to a twenty-eighth aspect of the present invention, in the twenty-sixth aspect or the twenty-seventh aspect, the modem device includes the uplink transmission line information included in the downlink carrier from the base station and the uplink transmission line held by the modem device. It is characterized by comprising a matching unit for matching information and a determining unit for determining whether to receive a downlink carrier based on a result of matching by the matching unit.

According to a twenty-ninth aspect of the present invention, based on the twenty-eighth aspect, the modem device has a search means for searching for a downlink carrier from the base station by changing a frequency, and the matching means detects the downlink carrier from the base station. If the uplink transmission line information included in the downlink carrier does not match the uplink transmission line information held by the modem, the search means continues to search for another downlink carrier.

The invention according to claim 30 is the invention according to any one of claims 26 to 29, wherein:
Upstream transmission line information from the associated modem device to the base station is held, and uplink transmission line information is broadcast to all modems connected to the communication system at regular intervals.

According to a thirty-first aspect of the present invention, in accordance with any one of the twenty-sixth to thirty-sixth aspects, the upstream transmission path information held by the modem device is transmitted by an external device connected to the modem device. The setting is changed.

According to a thirty-second aspect of the present invention, in the invention according to any one of the twenty-sixth to thirty-first aspects, the communication system is provided with management means for managing a state of the communication system. Features.

According to a thirty-third aspect of the present invention, in the thirty-second aspect of the invention, when a new modem device is added to the communication system, the management means is configured to receive an IP address issuance request from the modem device. And issues an IP address.

According to a thirty-fourth aspect, in the invention according to any one of the twenty-sixth to thirty-fourth aspects, the communication system performs communication via a CATV (cable television) line.

According to a thirty-fifth aspect of the present invention, in the invention according to any one of the twenty-sixth to thirty-fourth aspects, the base station comprises:
It is characterized by having a cable modem termination system (CMTS).

According to a thirty-sixth aspect of the present invention, in the thirty-fourth or thirty-fifth aspect, the modem device is a CATV.
(Cable television) It is a cable modem device (CM) connected to a line.

According to a thirty-seventh aspect, in the thirty-fourth aspect of the present invention, the communication system is a cable modem system for performing communication via a CATV (cable television) line. It is characterized by.

According to a thirty-eighth aspect of the present invention, in the thirty-seventh aspect, the communication system converts an optical signal into an electrical signal and converts an electrical signal into an optical signal for each cable modem device (CM). It is characterized by comprising a conversion means.

According to a thirty-ninth aspect of the present invention, in the invention according to any one of the thirty-fifth to thirty-eighth aspects, the cable modem termination system (CMTS) comprises: GT counter means for outputting a reference signal at regular time intervals; MAC processing means for processing the MAC information, multiplexing means for multiplexing the MAC information and user data processed by the MAC processing means, and modulation for modulating the MAC information and user data multiplexed by the multiplexing means Means for converting the MAC information and user data modulated by the modulation means to a predetermined frequency and outputting the converted data. The MAC information and user data converted to the predetermined frequency by the conversion means are downloaded. It is characterized by outputting to a line.

The invention according to claim 40 is characterized in that, in the invention according to claim 39, the modulating means modulates by a QAM system.

According to the invention of claim 41, in the invention of any one of claims 35 to 40, the cable modem termination system (CMTS) tunes an input signal from an uplink to a desired carrier frequency. Tuning means, demodulating means for demodulating an input signal tuned by the tuning means, separating means for separating the input signal demodulated by the demodulating means into MAC information and user data, and user data separated by the separating means. User data processing means for processing, and outputs the user data processed by the user data processing means to a CATV line.

[0062] The invention according to claim 42 is characterized in that, in the invention according to claim 41, the demodulation means demodulates by 16QAM system or QPSK system.

According to a thirty-third aspect of the present invention, the cable modem device (CM) according to any one of the thirty-sixth to thirty-sixth aspects comprises a filter means for filtering an input signal from a CATV line. Tuning means for tuning the input signal filtered by the filter means to a desired carrier frequency, demodulation means for demodulating the input signal tuned by the tuning means, and MAC information contained in the input signal demodulated by the demodulation means. Processing means for processing the data, interface means for outputting user data to the terminal device based on the MAC information processed by the MAC processing means, and storage means for temporarily storing the user data input via the interface means And the user data stored by the storage means,
A modulating means for modulating the signal to which the C information is added, a converting means for converting the signal modulated by the modulating means to a predetermined frequency and outputting the same, and a control means for controlling each section, The frequency-converted signal is filtered by the filter means and then output to the CATV line.

The invention described in claim 44 is characterized in that, in the invention described in claim 43, the demodulation means performs demodulation by the QAM system.

The invention according to claim 45 is characterized in that, in the invention according to claim 43 or 44, the modulating means modulates by a 16 QAM system or a QPSK system.

The invention according to claim 46 is the communication system according to any one of claims 35 to 45, wherein the communication system is output from each of a plurality of cable modem termination systems (CMTS) constituting a base station. Multiplexing means for frequency-multiplexing the downlink carrier obtained, conversion means for converting the downlink carrier frequency-multiplexed by the multiplexing means into an optical signal, and distribution means for distributing the optical signal converted by the conversion means. It is characterized by having.

The invention according to claim 47 is the invention according to claim 46, characterized in that the plurality of cable modem termination systems (CMTS) are connected by Ethernet between the respective cable modem termination systems (CMTS). And

According to a forty-eighth aspect of the present invention, in the authentication method for a communication system comprising an asymmetric transmission line, the modem device holds the upstream transmission line information contained in the downstream carrier from the base station and the modem device. A matching step of matching uplink transmission path information, and a determining step of determining whether to receive a downlink carrier based on a result of the matching by the matching step,
It is characterized by having.

The invention according to claim 49 is the invention according to claim 48, wherein the modem device has a search step of searching for a downlink carrier from the base station by changing the frequency, and the search step is performed by the collation step. If the uplink transmission line information included in the downlink carrier does not match the uplink transmission line information held by the modem, the search process continues to search for another downlink carrier.

The invention according to claim 50 is the invention according to claim 48 or 49, wherein the base station holds uplink transmission line information from a modem device belonging to the base station and transmits the uplink transmission line information for a predetermined period. It has a notifying step of notifying all modems connected to the communication system every time.

The invention according to claim 51 is the invention according to any one of claims 48 to 50, wherein the upstream transmission line information held by the modem device is transmitted by an external device connected to the modem device. The setting is changed.

The invention according to claim 52 is the invention according to any one of claims 48 to 51, characterized in that the communication system has a management step of managing the state of the communication system.

According to a fifty-third aspect of the present invention, in the invention according to the fifty-second aspect, the management step is based on an IP address issuance request from the modem device when a new modem device is added on the communication system. And issues an IP address.

The invention according to claim 54 is characterized in that, in the invention according to any one of claims 48 to 53, the communication system performs communication via a CATV (cable television) line.

The invention according to claim 55 is the invention according to any one of claims 48 to 54, wherein the base station comprises:
It is characterized by having a cable modem termination system (CMTS).

The invention according to claim 56 is the invention according to claim 54 or 55, wherein the modem device is a CATV.
(Cable television) It is a cable modem device (CM) connected to a line.

The invention according to claim 57 is the invention according to claims 54 to 56, wherein the communication system is a CATV.
(Cable television) It is a cable modem system that performs communication via a line.

According to a fifty-eighth aspect of the present invention, in the invention according to the fifty-sixth or fifty-seventh aspect, the communication system converts an optical signal into an electrical signal and converts an electrical signal into an optical signal for each cable modem device (CM). And a photoelectric conversion step.

According to a fifty-seventh aspect of the present invention, in the invention according to any one of the fifty-fifth to fifty-eighth aspects, the cable modem termination system (CMTS) outputs a reference signal at regular time intervals; A MAC processing step of processing the MAC information, a multiplexing step of multiplexing the MAC information and the user data processed by the MAC processing step, and a modulation of modulating the MAC information and the user data multiplexed by the multiplexing step And a conversion step of converting the MAC information and user data modulated by the modulation step to a predetermined frequency and outputting the converted information. The MAC information and user data converted to the predetermined frequency by the conversion step are downloaded. It is characterized by outputting to a line.

The invention according to claim 60 is characterized in that, in the invention according to claim 59, the modulation step modulates by a QAM system.

According to the invention of claim 61, in the invention of any one of claims 55 to 60, the cable modem termination system (CMTS) tunes an input signal from an uplink to a desired carrier frequency. A tuning step, a demodulation step of demodulating the input signal tuned in the tuning step, a separation step of separating the input signal demodulated in the demodulation step into MAC information and user data, and a user data separated in the separation step. A user data processing step of processing, and outputting the user data processed in the user data processing step to a CATV line.

The invention according to claim 62 is characterized in that, in the invention according to claim 61, the demodulation step demodulates by 16QAM system or QPSK system.

According to the invention of claim 63, in the invention of any of claims 56 to 62, the cable modem apparatus (CM) includes a filter step of performing a filtering process on an input signal from a CATV line. A tuning step of tuning the input signal filtered by the filtering step to a desired carrier frequency, a demodulating step of demodulating the input signal tuned by the tuning step, and MAC information included in the input signal demodulated by the demodulating step. Processing step, an interface step of outputting user data to a terminal device based on the MAC information processed in the MAC processing step, and a storage step of temporarily storing user data input via the interface step And the user data stored in the storing step is added to the MA by the MAC processing step.
A modulation step of modulating the signal to which the C information is added, a conversion step of converting the signal modulated by the modulation step to a predetermined frequency and outputting the same, and a control step of controlling each unit. The frequency-converted signal is filtered by a filtering process and then output to a CATV line.

The invention according to claim 64 is characterized in that, in the invention according to claim 63, the demodulation step modulates by a QAM system.

The invention according to claim 65 is characterized in that, in the invention according to claim 63 or 64, the modulation step modulates according to a 16 QAM system or a QPSK system.

According to a 66th aspect of the present invention, in the invention according to any one of the 55th to 65th aspects, the communication system is output from each of a plurality of cable modem termination systems (CMTS) constituting a base station. A multiplexing step of frequency-multiplexing the downlink carrier obtained, a conversion step of converting the downlink carrier frequency-multiplexed by the multiplexing step into an optical signal, and a distribution step of distributing the optical signal converted by the conversion step. It is characterized by having.

The invention according to claim 67 is characterized in that, in the invention according to claim 66, the plurality of cable modem termination systems (CMTS) are connected by Ethernet between the respective cable modem termination systems (CMTS). And

[0088]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a communication system and an authentication method according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. 1 to 13 show an embodiment in which a communication system according to the present invention is applied to a cable modem system. Note that the cable modem system applied in the embodiment of the present invention is based on the DOCSIS specification.

This DOCSIS (Data Over Cable Syst
em Interface Specification) is an interface that allows cable modems to communicate with each other by various companies with the aim of promoting the spread of cable modems for high-speed data communication using the infrastructure of cable television. Things.

DOCSIS, under the leadership of Cable labs, is a North American CATV provider (Comcast Cable Communicatio).
NS, Cos Communications, Tele Communications
CA, TimeWarner Cable, etc.), cable modem vendors, and network equipment vendors using CA using HFC (Hybrid-Fiber / Coax) including cable modems.
MC that standardizes data communication on TV systems
It has been formulated as an industry specification for cable modems by NS (Multimedia Cable Network System).

The DOCSIS (DOCS (Da
The “ta over cable system” ”enables a TCP / IP protocol communication using a cable modem, and is also provided with a security and accounting function.

The interface specified by DOCSIS is a phase 1 that specifies a data communication protocol.
(Phase 1), security, accounting,
Phase 2 (Phase 2), which controls device settings and controls the interface from the cable modem to the public telephone line
2) and an HFC (Hybrid-Fiber / Coax) cable, that is, a phase 3 that defines a low-level name connection interface between a modem and security via a hybrid cable. . Hereinafter, a communication system and an authentication method according to an embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a system configuration when a communication system according to the present invention is applied to a cable modem system. In FIG. 1, a cable modem system according to an embodiment of the present invention includes a CATV station (base station).
CMTS (Cable Modem Termination System) 1-3
And a MIX, E / O, DIS (mixing, photoelectric conversion, optical distribution) section 4 and an NMS (network monitoring system) 5. NODEs 11 to 16 and a CM (cable modem) 21 are provided on the subscriber line side. To 26 and a terminal device (not shown) connected to each of the CMs 21 to 26.

CMTS (Cable Modem Termination System)
Reference numerals 1 to 3 denote base stations for transmitting image information and audio information received via a wired line, a wireless line, a satellite line, or the like using Ethernet or the like to a downlink channel. The carriers transmitted in the downstream direction are MIX, E
/ O, DIS (mixing / photoelectric conversion / light distribution) unit 4 to send to NODEs 11 to 16 and further to each NODE 11
After being sent to the CMs 21 to 26 provided for each of the 16 to １６16, they are sent to individually connected terminal devices. In addition, in order to transmit information input by each terminal device to an uplink channel, the carrier in the uplink direction is CM2.
And transmitted to CMTSs 1 to 3 via NODEs 11 to 16.

The MIX, E / O, DIS (mixing, photoelectric conversion, optical distribution) section 4 receives F1, F2, F3 transmitted from each of the CMTSs 1 to 3 at different frequencies, and inputs the respective frequencies (F1, F1). F2, F3) are mixed by multiplexing, and after the photoelectric conversion processing is performed, the optical distribution processing is performed on the subsequent NODEs 11 to 16.
The optical signals distributed to the respective NODEs 11 to 16 are exactly the same optical signals.

NMS (Network Monitoring System) 5
Is provided for setting the ID information of the transmission line routes a to f assigned to the CMTSs 1 to 3, respectively. The NMS 5 needs to dynamically assign an IP address to each of the CMs 21 to 26 connected to the cable modem system.
It also has a function as a DHCP server that assigns an IP address to each of the CMs 21 to 26 using a protocol such as mic Host Configuration Protocol).

NODEs 11 to 16 are O / Es for converting an optical signal transmitted by an optical fiber cable into an electric signal.
A conversion function for converting an electric signal transmitted from the CM into an optical signal for transmission through an optical fiber cable;
It has an / O conversion function.

In the above system configuration, there is logically one downstream transmission line (route). The above three CMTs
Downstream carriers transmitted from S1 to S3 have different frequencies F1, F2, and F3, respectively.
The IX, E / O, and DIS units 4 perform mixing (frequency multiplexing) → photoelectric conversion → light distribution processing, and send out to all optical fiber routes. Although this optical fiber route is made up of physically separate optical fibers, the signals flowing through them are exactly the same.

The upstream transmission path (route) is configured to be subdivided for each path. As shown in FIG. 1, there are a total of six upstream transmission lines, and the CMTS 1 is configured to accommodate routes a and b, the CMTS 2 to accommodate routes c and d, and the CMTS 3 to accommodate routes e and f.

In each of the CMTSs 1 to 3, NMS (network monitoring system) 5 sets up upstream transmission line route ID information (a to f) accommodated by each of the CMTSs 1 to 3. In the example of FIG. 1, it is set so that CMTS1: routes a and b CMTS2: routes c and d CMTS3: routes e and f are accommodated, respectively. Each C
MTS1 to MTS3 are the set uplink transmission route IDs
By sending information in the downward direction at regular intervals, each CM
Notify to 21-26.

Each of the CMs 21 to 26 sets, for each CM, uplink transmission route ID information to the CMTS to which it belongs. In the example of FIG. 1, CM21: root a, CM22: root b, CM23:
Root c CM24: Root d, CM25: Root e, CM26:
The route f 1 and one CM are set to have one uplink transmission route ID information.

FIG. 2 is a block diagram showing a schematic configuration of a CMTS when the communication system according to the present invention is applied to a cable modem system. In FIG. 2, a CMTS (cable modem termination system) according to an embodiment of the present invention
Is a GT (global time) counter 11 and a DOC
SIS / MAC processing unit 12, MAC / user data multiplexing unit 13, QAM modulation unit 14, UP converter 15
, A TUNNER unit 16, a 16 QAM / QPSK demodulation unit 17, a MAC / user data classification unit 18, and a user data processing unit 19.

The GT counter 11 is a counter for measuring synchronization timing at the time of establishing communication with a CM (cable modem) not shown, and outputs current time information at regular intervals.

The MAC processing unit 12 has a Media Access Control
rol: A mechanism for outputting media access control information (MAC information). The MAC is connected to a lower layer close to the physical layer excluding the LLC (logical link control sublayer) in the second layer data link layer of the OSI (Open System Interconnection) reference model, and is connected. This is to generate and output transmission right control information so that frames transmitted from each do not collide with each other.

The MAC / user data multiplexing unit 13 multiplexes the media access control information from the MAC processing unit 12 and user data from a user data processing unit 19 described later.

The QAM modulator 14 is a quadrature amplifier.
de Modulation (quadrature amplitude modulation) is a modulation method that changes not only the phase of a carrier but also the amplitude itself according to a data signal. In the QAM modulator 14,
It has a function of adding a redundant code for error detection and correction on a CATV line.

[0107] The UP converter 15 is
After being further converted to a predetermined frequency, and transmitted to the downlink.

The tuning section 16 usually includes an RF amplifier, a local oscillator, a mixer stage, and the like, and converts a signal transmitted from the subscriber line-side terminal device via the uplink to a preferable carrier frequency. Synchronize.

The 16QAM / QSPK demodulation unit 17 is for demodulating a signal tuned to a preferable carrier frequency by the tuning unit 16. Note that this 16QAM / QP
The SK demodulation unit 17 has a function of verifying and removing a redundant code for detecting and correcting a transmission error on a transmission path, and correcting the error.

16QAM is 16-point QA
M, one of the high-efficiency digital modulation schemes, four-layer A
An SK (amplitude shift keying) wave is orthogonally synthesized, and the number of signal points is 1
Six. It is possible to transmit 4 bits of information per symbol.

[0111] QPSK stands for Quadrature Phase Shift Key.
ing (four-phase differential phase modulation), which is one of the modulation methods of a phase digital signal. The carrier is divided into two using a hybrid circuit or two circulators so as to have a phase difference of π / 2, and each carrier is subjected to PSK (phase shift keying) to obtain a four-phase P
This is a method for generating SK.

The MAC / user data classifying unit 18
From the signal demodulated by the QAM / QSPK demodulation unit 17, MAC (media access control) information and user data are classified. The MAC information classified here is M
The data is sent to the AC processing unit 12 and the user data is sent to the user data processing unit 19.

The user data processing unit 19 receives the user data classified by the MAC / user data classification unit 18 and performs format conversion and the like for transmitting the data to a network such as Ethernet.

FIG. 3 is a block diagram showing a schematic configuration of a CM in the communication system according to the embodiment of the present invention.
In FIG. 3, the CM according to the embodiment of the present invention includes a digital filter 210, a tuning unit 211, a QAM demodulation unit 212, a MAC processing unit 213, and a data memory 214.
, Ethernet I / F 215, control unit 216, 16QA
M / QPSK modulation section 217 and UP converter 218
And is configured.

The digital filter 210 is a filter circuit provided for extracting only a signal in a desired frequency band from a signal input via a CATV line. For example, a configuration is adopted in which a high-pass filter is provided when the signal is an upstream signal, and a low-pass filter is provided for a downstream signal.

The tuning section 211 tunes a signal in a desired frequency band extracted by the digital filter 1 to a preferable carrier frequency.

The QAM demodulation section 212 performs quadrature amplitude demodulation on the signal tuned to the preferred carrier frequency by the tuning section 211.

The MAC processing unit 213 is provided for the QAM demodulation unit 21
Based on the MAC information included in the signal demodulated by 2, user data is transmitted to a terminal device used by the user via an Ethernet I / F 215 at a subsequent stage.

The data memory 214 is a memory that stores an operation control program of the CM itself and has a buffer function for temporarily storing received user data and user data to be transmitted.

An Ethernet I / F 215 is an interface for connecting to a personal computer or the like which is a terminal device on the subscriber line side. The received data stored in the data memory 214 is processed by the MAC processing unit 213. This is an interface for transmitting to the terminal device based on the media access control information or for temporarily storing transmission data input from the terminal device in the data memory 214.

The cable for connecting the Ethernet I / F 215 and the terminal device is an Ethernet 10B.
A 10 Mbps twisted pair cable or the like having a transmission capacity based on ASE-T is used.

The 16 QAM / QPSK modulation section 217 applies the MA to the transmission data stored in the data memory 214.
The signal to which the control information is added is modulated by the C processing unit 213. This modulation method is described below.

16QAM is 16-point QA
M, one of the high-efficiency digital modulation schemes, quaternary A
The number of signal points obtained by orthogonally combining SK (wideband shift keying) waves is 1
Six. It is possible to transmit 4 bits of information per symbol.

QPSK stands for Quadrature Phase Shift Key.
ing (four-phase differential phase modulation), which is one of the modulation methods of a phase digital signal. The carrier is divided into two using a hybrid circuit or two circulators so as to have a phase difference of π / 2, and each carrier is subjected to PSK (phase shift keying) to obtain a four-phase P
This is a method for generating SK.

The UP converter 217 uses the above 16QA
After amplifying the signal modulated by the M / QPSK modulator 217 to a predetermined size, the signal is transmitted to the DF1 described above.

FIG. 4 is a flowchart showing the operation of the CM when the communication system according to the embodiment of the present invention is applied to a cable modem system. In FIG. 4, each C
As a method of setting the upstream transmission line route ID information in M, for example, a console device or the like is connected to a serial port provided for each CM, and a desired setting value is input by a user, so that the CM belongs to the CM. It is assumed that uplink transmission route ID information to the CMTS to be transmitted is set.

In FIG. 4, the CM is in a state where it is always searching for carriers transmitted in the downward direction. First, it is determined whether or not a carrier exists in the downlink direction (step S1). If a downlink carrier exists, uplink transmission route ID information included in the downlink carrier is received (step S2).

In step S2, the CM determines whether or not the received upstream transmission line route ID information includes the upstream transmission line route ID information held by the CM itself (step S3). If yes (step S3 / YES), an authentication process is performed using this downlink carrier (step S4).

In step S3, if the upstream transmission line route ID information held by the CM itself is not included in the received upstream transmission line route ID information (step S3 / NO), the next downstream carrier ( (Frequency), and the carrier search process is continued (step S5).

In each CM, a search process for a downlink carrier is performed while changing a tuning frequency. When an arbitrary downlink carrier is found, the uplink transmission route ID information notified by the downlink carrier is checked, and each CM is checked. If the uplink transmission route ID information held by itself is included, the authentication process is performed using the carrier. If the ID information is not included, the authentication operation is not performed and another carrier is re-assigned. Move to search operation.

Thereafter, the CM continues the carrier search process until it finds a downstream carrier including the upstream transmission route ID information held by the CM itself.

FIG. 5 is a sequence chart showing an operation example when the communication system according to the embodiment of the present invention is applied to a cable modem system. In FIG. 5, CM
Is turned on, the CM itself proceeds to step S in FIG.
As shown in FIG. 1, a search process is performed to determine whether a downlink carrier exists.

At this time, when a carrier frequency (carrier) in the downlink direction which has been successfully ranging last time is stored, it is possible to operate to search from the stored carrier.

The CMTS constantly and cyclically broadcasts SYNC / UCD / MAP messages to the CM on the downlink channel. Note that the transmission periods of these messages are different from each other.

When the CM establishes QAM / FEC lock, that is, synchronization in the physical layer, the CM “SYNC”
Message "is received, and the process proceeds to the SYNC synchronization phase.

In the SYNC synchronization phase, the GT value of the CM itself is synchronized with the reference signal output from the GT counter of the CMTS.

In the above-described synchronization establishment operation, as shown in FIG. 6, a MAC (media access control) management message header from the CMTS to the CM and a GT counter provided in the CMTS are counted. The CMTS time stamp is sent. CM
Is based on the CMTS time stamp.
This is repeated until the synchronization with is completely established.

In the SYNC synchronization phase, when synchronization between the CM and the CMTS is established, a “UCD message” is received. This UCD message is
It is a Channel Descriptor and is composed of various parameters of the uplink transmission signal such as the symbol rate and the frequency of the uplink signal. For example, FIG. 7 illustrates one embodiment of a UCD message.

In FIG. 7, the UCD message is MA
C management message header, uplink transmission line ID information, configuration change counter, minislot size, downlink transmission line route ID information, TLV encoded information, TLV encoded burst descriptor, encoded burst description And a child.

The MAC management message header is a management message for performing media access control.

The upstream transmission route ID information indicates the upstream channel number in the CMTS defined by the UCD message.

The configuration change counter is
This is a counter that increases the value by one every time the channel descriptor is changed by the CMTS. If the counter value does not change in the UCD message, the CM determines that there is no change in the remaining fields and ignores the remaining message information. This counter value is MAP (Up
stream Bandwidth Allocation MAP).

The mini-slot size is size information of the mini-slot in the above-mentioned uplink transmission line.

The downstream transmission line route ID information is an identifier arbitrarily selected by the CMTS, and is identification information of the downstream transmission line route.

The information other than the above is all parameter information encoded in the TLV format.

For example, FIG. 8 is a diagram showing an embodiment of the parameter information encoded in the TLV format. Here, symbol rate and frequency information are shown as parameter information. The symbol rate and the frequency information of the uplink signal shown in FIG. 5 are transmitted in this manner.

As described above, upon receiving the uplink frequency information and the symbol rate transmitted in the TLV format by the UCD message, the CM next receives the "MAP message".

This MAP message is information on the allocation of an upstream time slot. Specifically, each time region is defined for each type such as for band allocation request, ranging, and user data.

At the time specified for ranging in the MAP message, the CM sends "RNG-REQ" to the CMTS to start the ranging process. The ranging process is started from this point, and RN
Until a G-RSP response is received, an RNG-REQ message is sent while changing the signal strength (level).

After notifying and correcting the level timing correction value, the CM repeats retransmission of the RNG-REQ message, and receives the “RNG-RSP (Success) message” indicating that the ranging was successful from the CMTS. , The ranging process is completed.

FIG. 9 shows the CM D when the communication system according to the embodiment of the present invention is applied to a cable modem system.
5 is a sequence chart showing an HCP phase.

In FIG. 9, a DHCP server is a protocol for automatically allocating an IP address to a CM. Since the CM itself operates as an IP host, the DHCP server obtains parameters other than the IP address. , Each NODE can be connected to this system just by TCP
/ IP communication can be performed.

In FIG. 9, first, a “DHCP DISCOVER message”, which is a connection request from the CM to the DHCP server, is sent to an unspecified DHCP server, and the DHCP server receiving this message becomes a transmission source. A “DHCP OFFER message” indicating that the connection request is accepted is transmitted to the CM.

The CM sends “DHCP” from the DHCP server.
OFFER message ”, the“ DHCP REQUE
ST message ", and requests assignment of an IP address to the connected NODE.

[0155] The DHCP server sets "DHCP REQUEST
Message, the message “DHCP A
CK message ”and the newly connected NODE
Assign an IP address to

FIG. 10 is a sequence chart of a Tod phase of a CM when the communication system according to the embodiment of the present invention is applied to a cable modem system.

In FIG. 10, the CM sends a “Time of Date Request message” to the TIME server to request acquisition of date and time information, and the TIME server receiving this message sends the “Time of Date Request message” to the CM. of Da
te Ack message ". The message from the TIME server is transmitted with the date and time information requested by the CM added.

FIG. 11 is a sequence chart of the Tftp phase of a CM when the communication system according to the embodiment of the present invention is applied to a cable modem system.

In FIG. 11, Tftp (Trivial File
The Transfer Protocol) phase is a file transfer protocol, and is a request for acquiring an operation parameter “Tftp Req” in order to acquire operation parameter information of the CM itself.
Tf that sent the "message" and received the message
The tp server sets the "T
ftp Data message ”to the CM.

FIG. 12 shows CMs when the communication system according to the embodiment of the present invention is applied to a cable modem system.
4 is a sequence chart of a registration phase.

In FIG. 12, the Registration phase is for performing authentication processing at the operation level.
Transmits “REG-REQ” to the CMTS, and “REQ-RSP” is transmitted from the CMTS to the CTS.
M. The subsequent operation is normally in a service-enabled state.

FIG. 13 shows a CMT when the communication system according to the embodiment of the present invention is applied to a cable modem system.
It is a figure which shows one Example of the notification format of the upstream transmission line route ID information which S transmits. As shown in FIG. 13, in consideration of new addition of a CMTS, expansion of an HFC (optical fiber / coaxial cable hybrid transmission line) network, and the like, it is desirable to notify the transmission line route information to be covered in a bitmap format.

In FIG. 13, the CMT shown in FIG.
This shows the case of S1, where bit n is the up route n
, And 1 is set in a bit corresponding to the covered transmission path route.

For example, in the case of a cable modem system of the DOCSIS specification, a method of defining a new TLV in an upstream channel information notification message (UCD message) and notifying this information is conceivable. In the example described above, the format is one that can support up to 16 routes, but it is naturally possible to use a format that can support more routes.

Next, a communication system and an authentication method thereof according to another embodiment of the present invention will be described. In the above-described embodiment of the present invention, the setting of the upstream transmission line route ID information held in each CM is performed by the console device externally connected to the CM, but the console device is installed in the house. To save the trouble of bringing in, the MAC of the CM
The correspondence information between the address and the uplink transmission route ID number is N
By registering in advance in an MS (Network Monitoring System) device and notifying the corresponding information from the NMS when the CM is activated, the system can be operated without providing a console device.

In this case, at the time of the first start-up, the CM needs to try the authentication processing for each downlink carrier, but when the first authentication is successful, the NMS notifies the parameters, and at the second and subsequent start-ups, Based on the notified parameters, it is possible to determine whether or not it is a usable downlink carrier before performing the authentication process.

The above-described embodiment is a preferred embodiment of the present invention, and various modifications can be made without departing from the spirit of the present invention. For example,
In the present embodiment, the NMS (network monitoring system) has a function as a DHCP server that dynamically allocates an IP address to each CM. However, each CMTS automatically recognizes the connection status of the CM and outputs a dedicated message. May be configured to individually notify the CM of the IP address.

[0168]

As is apparent from the above description, according to the modem device, the communication system and the authentication method of the present invention, the reception confirmation of the downlink carrier and the check of the uplink transmission route ID information included in the received message are performed. , Each CM decides whether to use this downlink carrier.
Can be determined.

Therefore, even in a communication system having a system configuration in which a plurality of carriers are generated in the same downstream trunk direction, CM authentication processing can be performed smoothly.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration when a communication system according to an embodiment of the present invention is applied to a cable modem system.

FIG. 2 is a block diagram illustrating a schematic configuration of a cable modem according to an embodiment of the present invention.

FIG. 3 is a block diagram illustrating a schematic configuration of a cable modem termination system according to an embodiment of the present invention.

FIG. 4 is a flowchart illustrating an operation example of a CM when the communication system according to the embodiment of the present invention is applied to a cable modem.

FIG. 5 is a sequence chart showing an operation example when the communication system according to the embodiment of the present invention is applied to a cable modem.

FIG. 6 is an example of a SYNC message in the embodiment of the present invention.

FIG. 7 is an example of a UCD message in the embodiment of the present invention.

FIG. 8 is an example of a TLV parameter in the embodiment of the present invention.

FIG. 9 is a sequence chart showing a DHCP phase in the embodiment of the present invention.

FIG. 10 is a sequence chart showing a TIME phase in the embodiment of the present invention.

FIG. 11 is a sequence chart showing a Tftp phase in the embodiment of the present invention.

FIG. 12 is a diagram illustrating Registra according to an embodiment of the present invention.
It is a sequence chart which shows a tune phase.

FIG. 13 is an example of uplink transmission route ID information notified from the CMTS in the embodiment of the present invention.

[Explanation of symbols]

1-3 CMTS (cable modem termination system) 4 MIX, E / O, DIS (mixing / photoelectric conversion / optical distribution) 5 NMS (network monitoring system) 11-16 NODE 21-26 CM

Claims (67)

[Claims] 1. A modem device for determining whether to receive a downlink carrier based on transmission path information. 2. The modem device according to claim 1, wherein the transmission path information is included in a downlink carrier from a base station. 3. The modem device according to claim 2, wherein the transmission line information is uplink transmission line information from the modem device to the base station. 4. The modem device according to claim 2, wherein the modem device holds uplink transmission path information for the base station. 5. The modem device receives the downlink carrier based on a comparison result between uplink transmission line information included in a downlink carrier from the base station and uplink transmission line information held by the modem device. 5. The modem device according to claim 4, wherein it is determined whether or not the modem is connected. 6. The modem device, further comprising: a search unit that searches for a downlink carrier from the base station; and
Checking means for checking the uplink transmission line information included in the downlink carrier and the uplink transmission line information held in the modem device, and determining whether to receive the downlink carrier based on a result of the checking by the checking unit. 6. A determination means, comprising:
The modem device according to the paragraph. 7. The modem device according to claim 6, wherein said search means searches for a downlink carrier from said base station while changing a frequency. 8. The modem device according to claim 1, wherein the modem device is a cable modem device connected to a CATV (cable television) line. 9. The modem device includes: a filter unit configured to filter an input signal from the CATV line; a tuning unit configured to tune the input signal filtered by the filter unit to a desired carrier frequency; Demodulation means for demodulating the input signal tuned by the tuning means; MAC processing means for processing MAC information included in the input signal demodulated by the demodulation means; and the MAC processed by the MAC processing means Interface means for outputting user data to a terminal device based on information; storage means for temporarily storing user data input via the interface means; and MAC for storing the user data stored by the storage means. Modulating means for modulating a signal to which MAC information has been added by a processing means; Means for converting the signal modulated by the means into a predetermined frequency and outputting the converted signal; and control means for controlling the respective units. The signal converted to a predetermined frequency by the conversion means is a filter that 9. The modem device according to claim 8, wherein the data is output to the CATV line after being filtered by the means. 10. The modem device according to claim 9, wherein said demodulating means demodulates by a QAM method. 11. The modem device according to claim 9, wherein said modulating means modulates according to a 16 QAM system or a QPSK system. 12. A communication system comprising a modem device for determining whether to receive a downlink carrier based on transmission path information. 13. The communication system according to claim 12, wherein the transmission path information is included in a downlink carrier from a base station. 14. The communication system according to claim 13, wherein said transmission path information is uplink transmission path information from said modem device to said base station. 15. The communication system according to claim 13, wherein the modem device holds uplink transmission path information for the base station. 16. The modem device receives the downlink carrier based on a comparison result between uplink transmission line information included in a downlink carrier from the base station and uplink transmission line information held in the modem device. The communication system according to claim 15, wherein it is determined whether or not the communication is performed. 17. The modem device, further comprising: a search unit that searches for a downlink carrier from the base station; and
Checking means for checking the uplink transmission line information included in the downlink carrier and the uplink transmission line information held in the modem device, and determining whether to receive the downlink carrier based on a result of the checking by the checking unit. 17. The communication system according to claim 13, further comprising: a determination unit. 18. The communication system according to claim 17, wherein said search means searches for a downlink carrier from said base station while changing a frequency. 19. The communication system according to claim 12, wherein the communication system includes management means for managing a state of the communication system. 20. The management device according to claim 13, wherein when a new modem device is added to the communication system, the management device issues an IP address based on an IP address issuance request from the modem device. Item 20. The communication system according to item 19. 21. The communication system according to claim 12, wherein the communication system performs communication via a CATV (cable television) line.
A communication system according to item 9. 22. The communication system according to claim 21, wherein the modem device is a cable modem device (CM) connected to the CATV (cable television) line. 23. A filter for filtering an input signal from the CATV line, wherein the cable modem device (CM) tunes the input signal filtered by the filter to a desired carrier frequency. Tuning means; demodulation means for demodulating the input signal tuned by the tuning means; MAC processing means for processing MAC information included in the input signal demodulated by the demodulation means; processing by the MAC processing means Interface means for outputting user data to the terminal device based on the received MAC information; storage means for temporarily storing user data input via the interface means; and the user stored by the storage means Modulates a signal obtained by adding MAC information to the data by the MAC processing means Adjusting means, converting means for converting the signal modulated by the modulating means to a predetermined frequency and outputting the signal, and controlling means for controlling the respective units, wherein the signal is converted to a predetermined frequency by the converting means. 23. The communication system according to claim 22, wherein said signal is output to said CATV line after being filtered by said filter means. 24. The demodulation means according to claim 23, wherein the demodulation is performed by a QAM method.
A communication system as described. 25. The communication system according to claim 23, wherein said modulating means modulates by 16 QAM system or QPSK system. 26. A communication system comprising an asymmetric transmission line, wherein a downlink carrier from a base station includes information on an uplink transmission line from a modem device belonging to the base station. 27. The communication system according to claim 26, wherein said modem device holds uplink transmission path information from said modem device to said base station. 28. The modem device, comprising: a collating unit for collating uplink transmission line information included in a downlink carrier from the base station with uplink transmission line information held by the modem device; 28. The communication system according to claim 26, further comprising: a determination unit configured to determine whether to receive the downlink carrier based on a result. 29. The modem device, further comprising: a search unit for searching for a downlink carrier from the base station by changing a frequency, and an uplink transmission path information included in the downlink carrier from the base station by the matching unit. 29. The communication system according to claim 28, wherein when the transmission path information and the uplink transmission line information held by the modem do not match, the search means continues to search for another downlink carrier. 30. The base station holds uplink transmission line information from a modem device to which the base station belongs to the base station, and transmits the uplink transmission line information to all modems connected to the communication system at regular intervals. The communication system according to any one of claims 26 to 29, wherein the communication is performed. 31. The apparatus according to claim 26, wherein the setting of the uplink transmission line information held by said modem device is changed by an external device connected to said modem device. Communication system. 32. The communication system according to claim 26, wherein the communication system includes a management unit that manages a state of the communication system. 33. The management means, when a new modem device is added to the communication system, issues an IP address based on an IP address issuance request from the modem device. Item 33. The communication system according to Item 32. 34. The communication system according to claim 26, wherein the communication system performs communication via a CATV (cable television) line.
A communication system according to item 9. 35. The communication system according to claim 26, wherein the base station includes a cable modem termination system (CMTS). 36. The communication system according to claim 34, wherein the modem device is a cable modem device (CM) connected to the CATV (cable television) line. 37. The communication system according to claim 34, wherein the communication system is a cable modem system that performs communication via the CATV (cable television) line. 38. The communication system according to claim 30, wherein each of the cable modem devices (CM) includes a photoelectric conversion unit that converts an optical signal into an electric signal and converts the electric signal into an optical signal. 38. The communication system according to claim 36, wherein: 39. The cable modem termination system (C)
(MTS) comprises: GT counter means for outputting a reference signal at regular time intervals; MAC processing means for processing MAC information; multiplexing means for multiplexing the MAC information processed by the MAC processing means with user data; A modulating unit that modulates the MAC information and the user data multiplexed by the multiplexing unit; and converts the MAC information and the user data modulated by the modulating unit to a predetermined frequency and outputs the frequency. Conversion means, and the MA converted to a predetermined frequency by the conversion means.
The communication system according to any one of claims 35 to 38, wherein C information and the user data are output to a downlink. 40. The apparatus according to claim 39, wherein the modulating means modulates by a QAM method.
A communication system as described. 41. The cable modem termination system (C)
MTS): a tuning unit for tuning an input signal from an uplink to a desired carrier frequency; a demodulation unit for demodulating the input signal tuned by the tuning unit; and an input signal demodulated by the demodulation unit. Separating means for separating the MAC data and the user data into user data; and user data processing means for processing the user data separated by the separating means, wherein the user data processed by the user data processing means is transmitted to the CATV. The communication system according to any one of claims 35 to 40, wherein output is performed to a line. 42. The communication system according to claim 41, wherein said demodulation means performs demodulation by 16 QAM or QPSK. 43. A filter for filtering an input signal from the CATV line, wherein the cable modem tunes the input signal filtered by the filter to a desired carrier frequency. Tuning means; demodulation means for demodulating the input signal tuned by the tuning means; MAC processing means for processing MAC information included in the input signal demodulated by the demodulation means; processing by the MAC processing means Interface means for outputting user data to the terminal device based on the received MAC information; storage means for temporarily storing user data input via the interface means; and the user stored by the storage means Modulates a signal obtained by adding MAC information to the data by the MAC processing means Adjusting means, converting means for converting the signal modulated by the modulating means to a predetermined frequency and outputting the signal, and controlling means for controlling the respective units, wherein the signal is converted to a predetermined frequency by the converting means. 43. The communication system according to claim 36, wherein the signal is output to the CATV line after being filtered by the filter unit. 44. The demodulation means according to claim 43, wherein demodulation is performed by a QAM method.
A communication system as described. 45. The communication system according to claim 43, wherein said modulating means modulates according to a 16 QAM system or a QPSK system. 46. The communication system, comprising: multiplexing means for frequency-multiplexing downlink carriers output from each of a plurality of cable modem termination systems (CMTS) constituting the base station; and frequency multiplexing by the multiplexing means. 46. A conversion unit for converting the converted downstream carrier into an optical signal, and a distribution unit for distributing the optical signal converted by the conversion unit, wherein: A communication system according to claim 1. 47. The communication system according to claim 46, wherein said plurality of cable modem termination systems (CMTS) are connected by Ethernet between respective cable modem termination systems (CMTS). 48. An authentication method for a communication system comprising an asymmetric transmission line, wherein the modem device comprises: an uplink transmission line information included in a downlink carrier from the base station; and an uplink transmission line information held by the modem device. And a determining step of determining whether or not to receive the downlink carrier based on a result of the checking by the checking step. 49. The modem device, further comprising: a search step of searching for a downlink carrier from the base station by changing a frequency; and an uplink transmission path information included in the downlink carrier from the base station in the collation step. 49. The authentication method of a communication system according to claim 48, wherein when the transmission path information held by the modem does not match, the search step continues to search for another downlink carrier. 50. The base station holds uplink transmission line information from a modem device belonging to the base station, and transmits the uplink transmission line information to all modems connected to the communication system at regular intervals. 50. The authentication method for a communication system according to claim 48, further comprising a notification step of performing notification. 51. The apparatus according to claim 48, wherein the uplink transmission line information held by said modem device is changed in setting by an external device connected to said modem device. Authentication method for a communication system. 52. The authentication method for a communication system according to claim 48, wherein the communication system has a management step of managing a state of the communication system. 53. The management step, wherein, when a new modem device is added on the communication system, an IP address is issued based on an IP address issuance request from the modem device. Item 52. The authentication method for a communication system according to Item 52. 54. The communication system according to claim 48, wherein the communication system performs communication via a CATV (cable television) line.
13. The authentication method for a communication system according to item 9. 55. The method according to claim 48, wherein the base station includes a cable modem termination system (CMTS). 56. The authentication method for a communication system according to claim 54, wherein the modem device is a cable modem device (CM) connected to the CATV (cable television) line. 57. The communication system according to claim 54, wherein the communication system is a cable modem system that performs communication via the CATV (cable television) line. Authentication method. 58. The communication system is configured to include a photoelectric conversion step of converting an optical signal into an electric signal and converting an electric signal into an optical signal for each of the cable modem devices (CM). The authentication method for a communication system according to claim 56 or 57. 59. The cable modem termination system (C)
MTS) includes: a GT counter step of outputting a reference signal at regular time intervals; a MAC processing step of processing MAC information; a multiplexing step of multiplexing the MAC information and user data processed by the MAC processing step. A modulation step of modulating the MAC information and the user data multiplexed by the multiplexing step; and converting the MAC information and the user data modulated by the modulation step to a predetermined frequency and outputting the converted frequency. The MA converted into a predetermined frequency by the conversion step.
The communication method according to any one of claims 55 to 58, wherein C information and the user data are output to a downlink. 60. The modulation method according to claim 59, wherein the modulation is performed by a QAM method.
An authentication method for a communication system according to claim 1. 61. The cable modem termination system (C)
MTS), a tuning step of tuning an input signal from an uplink to a desired carrier frequency, a demodulation step of demodulating the input signal tuned in the tuning step, and an input signal demodulated in the demodulation step. A separating step of separating the MAC information and the user data into user data; and a user data processing step of processing the user data separated by the separating step. The user data processed by the user data processing step is stored in the CATV. The authentication method for a communication system according to any one of claims 55 to 60, wherein the method is output to a line. 62. The authentication method for a communication system according to claim 61, wherein in the demodulating step, demodulation is performed by a 16 QAM system or a QPSK system. 63. A filter step for filtering an input signal from the CATV line, and the cable modem apparatus tunes the input signal filtered by the filter step to a desired carrier frequency. A tuning step; a demodulation step of demodulating the input signal tuned in the tuning step; a MAC processing step of processing MAC information included in the input signal demodulated in the demodulation step; An interface step of outputting user data to a terminal device based on the obtained MAC information; a storage step of temporarily storing user data input through the interface step; and the user stored by the storage step Modulate a signal obtained by adding MAC information from the MAC processing step to data. Adjusting step, converting the signal modulated by the modulation step to a predetermined frequency and outputting the converted signal, and controlling the respective parts, and converting the signal into a predetermined frequency by the conversion step. 63. The authentication method for a communication system according to claim 56, wherein the signal is output to the CATV line after being filtered by the filtering process. 64. The method according to claim 63, wherein the demodulation step modulates by a QAM method.
An authentication method for a communication system according to claim 1. 65. The authentication method for a communication system according to claim 63, wherein the modulating step modulates according to a 16QAM system or a QPSK system. 66. The communication system, comprising: a multiplexing step of frequency-multiplexing downlink carriers output from each of a plurality of cable modem termination systems (CMTS) constituting the base station; 66. A conversion step of converting the converted downstream carrier into an optical signal, and a distribution step of distributing the optical signal converted by the conversion step. 3. The authentication method for a communication system according to claim 1. 67. The authentication method for a communication system according to claim 66, wherein the plurality of cable modem termination systems (CMTS) are connected to each other by Ethernet.