KR100590873B1 - method and apparatus for set up of channel in cable modem - Google Patents

Abstract

The present invention relates to a channel setting apparatus and a method of a cable modem, when the cable modem is connected to the cable network, by sequentially scanning channels according to different standards, such as a dachsis standard and Eurodax standard, and automatically By setting up a downstream channel to receive cable signals, it is possible to reduce the manpower, time, and development costs required to develop a cable modem, which is generated by separately developing cable modems that meet different standards.

Description

Channel setting apparatus and method thereof for cable modem {{method and apparatus for set up of channel in cable modem})             

1 is a block diagram illustrating a cable network including a typical cable modem.

2 is an internal block diagram illustrating a channel setting apparatus of a cable modem according to an exemplary embodiment of the present invention.

3A is a diagram for explaining a channel frequency table according to one embodiment of the present invention;

3B is a diagram for explaining a channel frequency table according to another embodiment of the present invention.

4A and 4B are flowcharts illustrating a flow of a channel setting method of a cable modem according to a preferred embodiment of the present invention.

5A and 5B are flowcharts illustrating a flow of a channel setting method of a cable modem according to another embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

1: Internet network

2: CTMS (cable modem termination system)

10 cable modem 11 cable interface

12: tuner 13: demodulator

14: pulse processor 15: control unit

15a: channel setting unit 16: memory

17: Ethernet interface unit 18; Modulator

19: AGC (Amplifier Gain Control) Processing Unit

The present invention relates to an apparatus and method for setting a channel of a cable modem. More specifically, a cable modem scans a channel according to both DOCSIS and EuroDOCSIS standards through a coaxial cable. Searching for a channel capable of correctly receiving a transmitted cable signal and setting the channel to the cable modem relates to a channel setting apparatus and method of the cable modem.

A general cable modem refers to a device that allows a communication terminal to perform data communication using a cable TV network.

That is, the cable modem converts the cable signal transmitted from the cable network into an IP packet, transmits the signal to the communication terminal, converts the IP packet transmitted from the communication terminal into a cable signal, and transmits the cable signal to the cable network.

In addition, a cable modem termination system (CMTS) is provided at the end of the cable network, and the CMTS converts an IP packet from a cable modem to the cable network and transmits the IP packet to the IP network and is transmitted from the IP network. Converts IP packets into cable signals and provides them to the cable modem.

Therefore, the user can access the IP network through the cable modem and receive the Internet service.

These cable modem specifications include the Data over cable service interface specifications (DOCSIS) standard set by CableLabs. Of the United States and the EuroDOCSIS standard set by tComLabs of Europe. data over cable service interface specifications.

DAXIS and EuroDAXIS, which are standard cable representatives of the present time, have differences in the downstream channel (Dpuwnstream Channel), and these differences can be described as shown in Table 1 below.

Dwownstream Channel Bandwidth Dwownstream PMD Sublayer Dwownstream Interleave Depth (I, J) Dwownstream Frequency Plan Upstream Frequency DOCSIS 6 MHz ITU-J.83-B (8.16). (16.8). (32.4). (64.2). (128.1) 93 MHz to 855 MHz 5 MHz to 42 MHz EuroDOCSIS 8 MHz ITU-J.83-A (12.17) 112 MHz to 858 MHz 5 MHz to 65 MHz

As described in Table 1, the bandwidth of the downstream channel according to the DAX standard is' 6MHz ', the Annex type is' B type', and the interleave depth is' (8.16). (16.8). (32.4). (64.2). (128.1) ', and the Frequency Plan is' 93MHz to 855MHz'.

Here, the Annex type information is information on a method of modulating / demodulating a cable signal according to each standard.

That is, the cable signal according to the DAXIS standard is modulated / demodulated in accordance with the recommendation of 'ITU-J.83-B', and the cable signal in the EuroDAX standard is modulated / demodulated according to the 'ITU-J.83-A' recommendation. do.

On the other hand, the bandwidth of the downstream channel according to the Euro Doc.s standard is '8MHz', the Annex type is 'A type', the Interleave Depth is '(12.17)', and the frequency plan ( Frequency Plan) is '112MHz ~ 85MHz'.

In addition, there is a slight difference in each upstream channel of the DAXIS standard and the EuroDAX standard.

Today, due to the difference between the downstream channel and the upstream channel between DAXIS and EuroDAX, cable modems that meet each specification are being developed separately.

In other words, DAXIS and EuroDAX are judged to be different cable modem standards, and are developing a cable modem hardware platform conforming to DAQS and a hardware platform conforming to EuroDAXIS standards. We are developing software to be programmed on our own.

Therefore, the separate development of the cable modem conforming to the Docsys standard and the cable modem conforming to the Eurodactix standard will increase the manpower, time and development cost required for the development of the cable modem more than a multiple.

In addition, in the case of producing a cable modem in accordance with each specification, if the production amount of the cable modem exceeds the consumption, it is difficult to manage two different cable modem.

As a result, the development and supply of cable modems becomes inflexible with respect to consumer market demands.

Therefore, the present invention was devised to solve the above problems, and it is possible to accommodate both the docsis standard and the Eurodaxis standard of the cable modem, so that the producer can flexibly cope with the demands of the consumer market. It is also an object of the present invention to provide a cable modem channel setting apparatus and a method for allowing a cable modem user to receive all of the services according to the Docxis and Eurodaxis standards using a single cable modem. .

An apparatus for setting a channel of a cable modem according to an aspect of the present invention for achieving the above object, the storage unit for storing at least one or more channel frequency information according to different standards, the channel frequency information stored in the storage unit and The channel is set according to the bandwidth information according to the cable standard, and the cable signal received through the channel is demodulated by the demodulation method according to the standard, and a) if the error does not occur in the demodulated packet, the set channel B) to a downstream channel of the cable modem, and b) a channel setting unit for setting a channel according to the next channel frequency information stored in the storage unit when an error occurs in the demodulated packet.

The channel setting unit of the apparatus for setting a channel of the cable modem according to the present invention, if the channel frequency information is stored for each standard in the storage unit, generates a frequency control signal according to the bandwidth information and the channel frequency information according to the standard and When channel frequency information according to each standard is sequentially stored, when generation of a frequency control signal using bandwidth information and channel frequency information according to one standard is completed, the bandwidth information and channel frequency information according to another standard are used. To generate a frequency control signal.

The channel setting unit of the apparatus for setting a channel of the cable modem according to the present invention, if the channel frequency information is stored for each standard in the storage unit, generates a demodulation setting signal according to the standard, and the channel frequency information for each standard If is sequentially stored, it generates a demodulation setting signal according to one standard, and when the scan of the channel according to the corresponding standard is completed, generating a demodulation setting signal according to another standard.

On the other hand, the apparatus for setting the channel of the cable modem according to the present invention, the cable interface unit for providing a cable signal by setting the channel according to the frequency control signal generated in the channel setting unit, and the demodulation setting generated in the channel setting unit Set a demodulation method according to the signal, demodulate the cable signal received through the cable interface unit to the set demodulation method, convert the packet signal into a packet, and compensate the cable signal provided by the cable interface unit to a predetermined level, A signal compensation unit provided, a control unit for transmitting the demodulated packet to the communication terminal via Ethernet, and a packet signal modulated by a modulation method corresponding to the demodulation method set in the demodulation unit, and a cable signal. It further includes a modulator for converting.

On the other hand, the method for setting the channel of the cable modem according to another aspect of the present invention, the step of storing the channel frequency information according to different standards, the demodulation method information according to each standard, the stored channel frequency information and cable Sequentially setting channels according to bandwidth information according to the standard, and allowing the cable signal received through the set channel to be demodulated by the demodulation method according to the standard, and if the error does not occur in the demodulated packet, the set channel is cabled. Setting to the downstream channel of the modem.

In addition, the method for setting a channel of a cable modem according to the present invention includes checking whether the strength of a received cable signal maintains a predetermined level, and if not, setting a channel according to the next stored channel frequency information; When the strength of the cable signal is maintained at a predetermined level, demodulating the cable signal according to the stored demodulation scheme information, converting the cable signal into a packet, and determining whether an error has occurred in the packet. The method may further include setting a channel according to the frequency information and setting the set channel as a downstream channel of the cable modem when an error does not occur in the packet.

And, in the step of setting the channel according to the next channel frequency information of the method for setting the channel of the cable modem according to the present invention, if the stored channel frequency information is stored for each standard, the last channel frequency information is stored in the corresponding standard And determining whether the channel frequency information is information, and, when the determination result is the last channel frequency information of the corresponding standard, setting a channel using a demodulation scheme and channel frequency information according to another standard.

In addition, if the channel according to the next channel frequency information of the method for setting the channel of the cable modem according to the present invention, and if the stored channel frequency information is stored sequentially, whether the previous channel frequency information is the last channel frequency information stored And determining whether the channel is the last stored channel frequency, and setting a channel using a demodulation scheme according to another standard and stored channel frequency information.

On the other hand, the apparatus for setting the channel of the cable modem according to another aspect of the present invention, the storage unit for storing channel frequency information according to different standards, the channel frequency information stored in the storage unit and the bandwidth information according to the cable standard A channel control unit generating a frequency control signal and generating a demodulation setting signal to demodulate a cable signal in a demodulation manner according to the standard, and setting a channel according to the frequency control signal generated by the channel control unit A demodulation method according to a demodulation setting signal generated by the channel control unit and a cable interface unit providing a cable signal, demodulating the cable signal received through the cable interface unit into the set demodulation method, and converting the packet signal into a packet; A demodulation section and a cable provided from the cable interface section If the call maintains a predetermined level, it is determined whether an error has occurred in the demodulated packet. If no error occurs, the channel set by the cable interface unit is set as a downstream channel of the cable modem. And a channel setting unit for generating a frequency control signal by using the next channel frequency information stored in the storage unit and bandwidth information according to a cable standard when an error occurs.

In addition, an apparatus for setting a channel of a cable modem according to another aspect of the present invention, the signal compensation unit for providing a demodulation unit to compensate the cable signal provided by the cable interface unit to a predetermined level, and the demodulated packet A control unit for transmitting to the communication terminal via Ethernet, and a modulation unit for modulating the packet transmitted from the communication terminal in a modulation method corresponding to the demodulation method set in the demodulator, and converts the packet to a cable signal.

The method for setting a channel of a cable modem according to another aspect of the present invention includes storing channel frequency information according to different standards, and storing demodulation scheme information according to each standard, and storing the stored channel frequency information. And setting a channel using the bandwidth information according to each standard, receiving a cable signal through the set channel, checking whether or not the strength of the received cable signal maintains a predetermined level. Setting a channel according to the stored next channel frequency information, demodulating the cable signal according to the stored demodulation scheme information and converting the cable signal into a packet if the strength of the cable signal maintains a predetermined level; Determining whether an error has occurred in the packet; c) if the error has occurred, storing the stored next channel frequency information. And d) setting an established channel as a downstream channel of the cable modem when no error occurs in the packet.

Hereinafter, a channel setting apparatus and a method of a cable modem according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram illustrating a cable network including a general cable modem.

As shown in FIG. 1, a cable communication network using a cable modem 10 may enable IP packet transmission between the Internet network 1, the Internet network 1, and an HFC network (Hybrid Fiber and Coax Network) 3. It includes a configured Cable Modem Termination System (CTMS) 2, an HFC network 3 composed of a cable modem 10 connected to a coaxial cable, and a communication terminal 20 connected to the cable modem 10.

The CMTS 2 may be a cable broadcaster or an Internet Service Provider (ISP), and provides a cable signal through the HFC network 30.

In addition, the CMTS 2 converts the cable signal into an IP packet and transmits it through the Internet network 1, and protects cable operators from routing and hacking for transmitting the cable signal in the cable network. Filtering and traffic to guarantee the quality of service to the subscriber.

The cable modem 10 converts the cable signal received from the CMTS 2 into an IP packet and transmits it to the communication terminal 20 through Ethernet, and converts the IP packet received from the communication terminal 20 through Ethernet into a cable signal. It converts and transmits the data to the CMTS 2 through the HFC network 3.

The communication terminal 20 is an end device of a cable network, and allows a user to receive a communication service through a cable network. Such a communication terminal 20 may be a personal computer, a Macintosh, a work station, a network computer, and other electronic devices.

2 is an internal block diagram illustrating a channel setting apparatus of a cable modem according to an exemplary embodiment of the present invention.

2, the cable modem 10 according to the present invention includes a cable interface unit 11, a tuner 12, a demodulator 13, a MAC processor 14, a controller 15, and a memory. 16, an Ethernet interface unit 17, a modulator 18, and an AGC (Amplifier Gain Control) processor 19, and the controller 15 includes a channel setting unit 15a.

The cable interface unit 11 is connected to the CMTS 2 by a coaxial cable, interfacing the cable modem 10 with the CMTS 2 so as to exchange cable signals, and via a downstream channel from the CMTS 2. There is no collision between the cable signal transmitted and the cable signal transmitted to the CMTS 2 via the upstream channel.

In addition, the cable interface unit 11 receives a cable signal, which is an RF signal, through a channel having a predetermined frequency band set according to the frequency control signal transmitted from the controller 15.

The tuner 12 then tunes the cable signal transmitted from the CMTS 2 via the cable interface 11.

The demodulator 13 demodulates the cable signal tuned by the tuner 12 according to a Quadrature Amplitute Modulation (QAM) method.

QAM refers to a technique of modulating a digital signal using a wavelength and a position of a carrier wave, and is a method of increasing information transmission efficiency by using carrier signals having mutual orthogonality.

In addition, the QAM system demodulated by the demodulator 13 includes a 64-QAM system and a 246-QAM system.

That is, the cable signal exchanged with the coaxial cable to which the CMTS 2 and the cable modem 10 are connected is a signal modulated by the QAM method, and the demodulator 13 of the cable modem 10 is the CMTS 2. The cable signal transmitted from the demodulated signal is demodulated according to the QAM method and converted into an IP packet.

The AGC processing unit 19 maintains the strength of the cable signal provided from the tuner 12 to the demodulation unit 13 at a predetermined level. That is, the demodulator 13 maintains the strength of the tuned signal at the tuner 12 at a predetermined level so that the cable signal can be demodulated correctly.

The AGC processor 10 corrects a gain difference between the signal strength fed back from the demodulator 13 and the cable signal strength provided from the tuner 12 to maintain a predetermined level of signal strength. In this case, the cable signal strength transmitted from the tuner 12 to the demodulator 13 is compensated for by the signal strength fed back from the demodulator 13 to maintain a predetermined signal level.

The MAC processor 14 performs a MAC process for transmitting the IP packet demodulated by the demodulator 13 to the communication terminal 20 via Ethernet.

In this case, the MAC processing means that the cable modem 10 transmits the demodulated IP packet to the communication terminal 20 through Ethernet. The cable MAC header including the cable MAC address of the communication terminal 20 is included in the IP packet. In addition, encapsulation.

Here, the source MAC address of the cable MAC header is the MAC address of the cable modem 10, and the Destination MAC address is the MAC address of the communication terminal 20.

In addition, the MAC processing unit 14 removes the cable MAC header from the IP packet transmitted from the communication terminal 20, and transmits it to the CMTS (2) through the coaxial cable.

The control unit 15 transmits the IP packet transmitted from the MAC processing unit 14 to the communication terminal 20, and transmits the IP packet transmitted from the communication terminal 20 to the MAC processing unit 14.

The Ethernet interface unit 17 is connected to the communication terminal 20 via Ethernet, and transmits an IP packet transmitted from the MAC processing unit 14 to the communication terminal 20 through Ethernet, and from the communication terminal 20 through Ethernet. The transmitted IP packet is transmitted to the controller 15.

The memory 16 stores operation information of the cable modem 10, MAC address information of the cable modem 10, MAC address information of the communication terminal 20 connected through Ethernet, channel frequency table information, and the like.

3A is a diagram for explaining a channel frequency table according to an embodiment of the present invention.

As shown in FIG. 3A, since the downstream frequency plan according to the DOCSIS standard is '93 MHz to 855 MHz 'and the channel bandwidth is' 6 MHz', the center frequency of each channel according to the DAXIS standard is sequentially arranged. In addition, since the downstream frequency plan according to the EuroDOCSIS standard is '112MHz to 858MHz' and the channel bandwidth is '8MHz', the center frequencies of each channel according to the Eurodaxis standard are sequentially arranged, Configure the channel frequency table.

That is, the CMTS 2 sequentially arranges the center frequencies of each channel through which the cable signals are transmitted by the CMTS, and the CMTS 2 sequentially arranges the center frequencies of each channel through which the cable signals are transmitted via the DAXIS standard.

At this time, the center frequency of each channel according to the docsis standard is arranged, the center frequency of each channel according to the Euro docsis standard, or the center frequency of each channel according to the Euro docsis standard is arranged, The center frequency of each channel can be arranged accordingly.

3B is a diagram for explaining a channel frequency table according to another embodiment of the present invention.

As shown in FIG. 3B, the center frequency of each channel conforming to the DAXIS standard and the center frequency of each channel conforming to the EuroDAQs standard may be mixed and arranged.

That is, the center frequency of each channel according to the DAXIS standard and the center frequency of each channel according to the EuroDAX standard may be sequentially arranged regardless of the type of the standard.

On the other hand, the channel setting unit 15a of the control unit 15 is connected to the CMTS 2 via the coaxial cable for the first time to the cable modem 10, or when the initial power is applied, the channel frequency stored in the memory 16. Referring to the table, a frequency control signal is generated, and the generated frequency control signal is transmitted to the cable interface unit 11.

In this case, the frequency control signal transmitted by the channel setting unit 15a includes center frequency information and bandwidth information of the channel.

In addition, the cable interface unit 11 connects to the CMTS 2 through a cable in a channel having a frequency range according to the frequency control signal transmitted from the channel setting unit 15a, and receives a cable signal through the channel.

In addition, the channel setting unit 15a allows the demodulator 13 to demodulate the cable signal according to the Annex B type (ITU J, 83-B) or the Annex A type (ITU J.83-A). A nex setting signal is generated and transmitted to the demodulator 13.

The demodulator 13 sets the anneal type according to the anneal setting signal transmitted from the channel setting unit 15a, and demodulates the cable signal transmitted from the tuner 12 according to the QAM method.

That is, the demodulator 13 sets the Annex B type or the Annex A type according to the Annex setting signal transmitted from the channel setting unit 15a, and sets the cable signal transmitted from the tuner 12 according to the set type. Demodulate

In addition, the channel setting unit 15a transmits the frequency control signal and the annex setting signal, and the tuner 12 tunes the cable signal received by the cable interface unit 11 through the channel according to the frequency control signal, and restores the signal. It is determined whether the cable signal transmitted to the grandfather 13 maintains a predetermined level strength.

That is, the channel setting unit 15a determines whether the AGC processing unit 19 correctly maintains the strength of the cable signal transmitted from the tuner 12 to the demodulation unit 13 at a predetermined level strength. Referring to the channel frequency table stored in 16), a frequency control signal according to the next center frequency is generated and transmitted to the cable interface unit 11.

In addition, the channel setting unit 15a checks whether the demodulator 13 corrects the Forward Error Correction (FEC) and the Motion Picture Expert Ground (MPEG) of the IP packet demodulated by the cable signal transmitted from the tuner 12. In this case, it is determined that the downstream channel is correctly obtained.

FEC is omnidirectional error correction. When the transmitting side transmits an error correction code in which additional information is added to a character or frame to be transmitted and the receiving side receives an error, the FEC is data for detecting and correcting the error using this additional information. .

That is, if the IP packet demodulated by the demodulator 13 is one complete IP packet, the channel setting unit 15a is a channel in which the cable interface unit 11 receives the cable signal, and the demodulator demodulates the cable signal. It is determined that the Nex type is set correctly.

On the other hand, if the FEC and MPEG of the IP packet demodulated by the demodulator 13 are not correct, the channel setting unit 15a refers to the channel frequency table stored in the memory 16 and according to the next center frequency, the frequency control signal. To generate and transmit it to the cable interface unit (11).

In addition, when the channel setting unit 15a generates the frequency control signal and the annex setting signal according to the next center frequency when the channel frequency table stored in the memory 16 is generated, the channel center frequency is set in the channel frequency table. It checks whether it is the last center frequency, and if it is the last channel center frequency, changes the anneal type to generate the anneal setting signal.

For example, when a channel frequency table as shown in FIG. 3A is set, the channel setting unit 15a generates a frequency control signal with reference to a center frequency '855 MHz' and bandwidth information '6 MHz', and generates a B-annex setting signal. In this case, the cable interface unit 11 receives a cable signal through a channel having a bandwidth of '852MHz to 858MHz', so that the FCE and MPEG of the IP packet demodulated by the demodulator 13 is B type is incorrect. If the strength of the cable signal is not maintained at a predetermined level, the channel setting unit 15a refers to '112 MHz', which is the first center frequency of the Eurodaxis standard, which is the next center frequency, and '8 MHz', which is the bandwidth of the Eurodaxis. To generate a frequency control signal, and to generate an A-anneal setting signal so that the demodulator 13 can demodulate according to the A type.

That is, the channel setting unit 15a sequentially generates the center frequency of each channel according to the daxim standard and the frequency control signal according to the bandwidth information by referring to the channel frequency table, and according to the center frequency of the last daxis standard. If the frequency control signal is generated, and the channel is not set correctly, the frequency control signal is generated according to the first center frequency according to the Eurodax standard, and the demodulator 13 has an Ax type of the Eurodax type. Generates an A-nex setup signal to reset to type.

According to another exemplary embodiment, when the channel frequency table as shown in FIG. 3B is set, the channel setting unit 15a may refer to the channel frequency table to determine '858 MHz', which is the last center frequency, and '6 MHz,' which is bandwidth information of the DAX standard. When generating a frequency control signal by using the signal, the B Annex setting signal, the cable interface unit 11 receives a cable signal through a channel having a bandwidth of '855MHz ~ 861MHz', the demodulator 13 is If the FCE and MPEG of the IP packet demodulated to type B are not correct, or if the strength of the cable signal is not maintained at a predetermined level, the channel setting unit 15a has a first center frequency of '93 MHz 'and a bandwidth of Eurodax. Referring to '8 MHz', the frequency control signal is generated, and the demodulator 13 generates the A anneal setting signal so that the demodulator 13 can demodulate according to the A type.

That is, the channel setting unit 15a generates a frequency control signal according to the last center frequency while generating a frequency control signal by sequentially using each center frequency and bandwidth information of the DAX standard with reference to the channel frequency table. Even if the channel is not set correctly, the frequency control signal is generated by using the first center frequency and bandwidth information of the Eurodaxis standard, and the demodulator 13 is an Annex type of Eurodaxis standard. Generates an A-anneal setup signal for demodulation according to type.

The channel setting unit 15a may be configured to generate a channel control unit (not shown) for generating the frequency control signal and the annex setting signal stored in the channel frequency table, and down the channel set in the cable interface unit 11 of the cable modem 10. A channel determiner (not shown) for determining a stream channel may be provided.

The modulator 18 modulates the IP packet transmitted from the communication terminal 20 in accordance with the Annex type set in the cable modem 10 and transmits the modulated IP packet to the CMTS 2.

In other words, the modulator 18 converts the IP packet into a cable signal according to the method in which the demodulator 14 demodulates the cable signal.

4A and 4B are flowcharts illustrating a flow of a channel setting method of a cable modem according to an exemplary embodiment of the present invention.

4A and 4B, first, a manufacturer or a user of the cable modem 10 sets a channel frequency table as shown in FIG. 3A and stores the channel frequency table in the memory 16 (S 1).

That is, the channel frequency table is set by sequentially arranging the center frequencies of the channels according to the DAXIS standard and sequentially the center frequencies of the channels according to the EuroDAQs standard.

Then, the channel setting unit 15a generates a frequency control signal according to the center frequency and the bandwidth of the dachsis standard by referring to the channel frequency table, and transmits it to the cable interface unit 11.

In addition, the channel setting unit 15a generates a B anneal setting signal so that the demodulator 13 is set to B type, which is an Annex type according to the DAX standard, and transmits the B anneal setting signal to the demodulator 13 (S 2). .

The cable interface unit 11 sets a channel according to the frequency control signal transmitted from the channel setting unit 15a and receives the cable signal transmitted through the cable.

The demodulator 13 sets the demodulation method to the B type according to the B anneal setting signal transmitted from the channel setting unit 15a, and demodulates the cable signal received through the cable interface unit 11.

According to an embodiment, the channel setting unit 15a generates a frequency control signal according to the center frequency '93MHz' and the bandwidth '6MHz' with reference to the channel frequency table, and the cable interface unit 11 generates the generated frequency. Depending on the control signal, the cable signal is received through a channel with a bandwidth of '90MHz to 96MHz'.

The tuner 12 tunes the cable signal received through the cable interface unit 11 and transmits the tuned signal to the demodulator 13.

At this time, the AGC processing unit 19 maintains the strength of the cable signal transmitted by the tuner 12 to the demodulator 13 at a predetermined level.

In other words, the AGC processor 19 compensates the strength of the cable signal transmitted by the tuner 12 and maintains the strength of the cable signal that the demodulator 13 can demodulate.

In addition, the channel setting unit 15a checks whether the strength of the cable signal transmitted from the tuner 12 to the demodulator 13 is maintained at a predetermined level (S 3).

As a result of the check, if the strength of the cable signal is not maintained at a predetermined level that can be demodulated by the demodulator 13, it is determined whether the center frequency of the channel set in the cable interface 11 is the last center frequency of the DAXIS standard. (S 4).

If the center frequency of the channel determined by the cable interface unit 11 and the last center frequency of the daxis standard are not equal to each other, the channel setting unit 15a refers to the channel frequency table and the center frequency of the next daxis standard. , And generates a frequency control signal according to the bandwidth, and transmits to the cable interface (11) (S 5).

If the center frequency of the set channel is the last center frequency of the DAXIS standard, the center frequency according to the EuroDAX standard and the frequency control signal according to the bandwidth are generated by referring to the channel frequency table. An A-anneal setting signal is generated to be set to an A-type that is an Annex type according to the Eurodaxis standard (S6).

That is, the channel setting unit 15a checks whether or not the center frequency of the channel set in the cable interface unit 11 is '855 MHz'. If the channel setting unit 15a is '855 MHz', the channel setting unit 15a determines that the scan of the channel according to the standard is completed. Initiate a scan of the channel according to the Eurodaxis specification.

Accordingly, the channel setting unit 15a generates a frequency control signal according to the first center frequency '112MHz' and the bandwidth '8MHz' to start scanning the channel according to the Eurodaxis standard. do.

In addition, the channel setting unit 15a generates the A anneal setting signal so that the demodulator 13 can set the A type, which is a demodulation method according to the Eurodaxis standard.

That is, if the center frequency of the channel set in the cable interface unit 11 is not '855 MHz', for example, '93 MHz ', the channel setting unit 15a refers to the channel frequency table and refers to the next center frequency '99 MHz. And generates a frequency control signal according to the bandwidth '6MHz' and transmits it to the cable interface unit 11.

On the other hand, when the channel setting unit 15a determines that the strength of the cable signal is maintained at a predetermined level, the demodulator 13 demodulates the cable signal according to the set B type and converts the cable signal into an IP packet (S 7).

The channel setting unit 15a then checks whether the FEC and MPEG data of the IP packet demodulated by the demodulator 13 are correct (S8).

As a result of the check, if the FEC and MPEG data are not correct, the channel setting unit 15a checks whether or not the center frequency of the channel set in the cable interface unit 11 is the last center frequency according to the DAX standard (S4).

On the other hand, if the FEC and MPEG data are correct as a result of the check, the channel setting unit 15a determines that the IP packet is completely demodulated, and sets the channel set in the cable interface unit 11 as the downstream channel of the cable modem 10. (S 9).

The MAC processor 14 adds the cable MAC header to the IP packet demodulated by the demodulator 13 and transmits the cable MAC header to the controller 15.

The control unit 15 transmits the IP packet transmitted from the MAC processing unit 14 to the communication terminal 20 through the Ethernet interface unit 17 (S 10).

The controller 15 transmits the IP packet transmitted from the communication terminal 20 through Ethernet to the MAC processor 14, and the MAC processor 14 receives the cable MAC header from the IP packet transmitted from the controller 15. Remove it and transmit it to the modulator 18.

The modulator 18 modulates the IP packet in accordance with the Annex type set by the channel setting unit 15a, converts the IP packet into a cable signal, and transmits the cable signal to the cable interface unit 11 (S11).

The cable interface unit 11 transmits the cable signal transmitted from the modulator 18 to the CMTS 2 through the upstream channel corresponding to the downstream channel set by the channel setting unit 15a (S 12).

5A and 5B are flowcharts illustrating a flow of a channel setting method of a cable modem according to another embodiment of the present invention.

5A and 5B, a manufacturer or a user of the cable modem 10 sets a channel frequency table as shown in FIG. 3B and stores the channel frequency table in the memory 16 (S 20).

That is, a channel frequency table in which the center frequency of each channel according to the DAXIS standard and the center frequency of each channel according to the EuroDAX standard is sequentially arranged regardless of the type of the standard is set.

The channel setting unit 15A sets a channel and an Annex type to be scanned (S21).

That is, the channel setting unit 15a generates a frequency control signal according to the center frequency and the bandwidth by referring to the channel frequency table stored in the memory 16, and transmits the generated frequency control signal to the cable interface unit 11. send.

The cable interface unit 11 sets a channel according to the transmitted frequency control signal and receives the cable signal.

The channel setting unit 15a generates a B anneal setting signal so that the demodulator 13 can demodulate according to the B type, which is a DAX standard, and transmits it to the demodulator 13.

According to an embodiment, the channel setting unit 15a generates a frequency control signal according to the first center frequency '93 MHz 'and the bandwidth' 6 MHz 'with reference to the channel frequency table as shown in FIG. Generates the B Annex setup signal.

The cable interface unit 11 receives a cable signal through a channel having a center frequency of '93 MHz 'according to the transmitted frequency control signal.

At this time, since the bandwidth of the channel that the cable interface unit 11 receives the cable signal is '6MHz', the cable signal of the '90MHz ~ 96MHz' has a cable signal.

The tuner 12 tunes the cable signal received through the cable interface unit 11 and provides it to the demodulator 13.

At this time, the AGC processing unit 19 maintains the strength of the cable signal transmitted by the tuner 12 to the demodulator 13 at a predetermined level.

In other words, the AGC processor 19 compensates the strength of the cable signal transmitted by the tuner 12 and maintains the strength of the cable signal that the demodulator 13 can demodulate.

The channel setting unit 15a checks whether or not the strength of the cable signal transmitted from the tuner 12 to the demodulator 13 is maintained at a predetermined level (S 22). As a result of the check, the channel setting unit 15a reaches a predetermined level. If not, the cable interface unit 11 checks whether the center frequency of the channel receiving the cable signal is the last center frequency of the set channel frequency table (S 23).

As a result of the check, the channel setting unit 15a generates a frequency control signal according to the next center frequency by referring to the channel frequency table if the center frequency of the channel set in the cable interface unit 11 is not the last frequency of the channel frequency table. Then, the frequency control signal is transmitted to the cable interface unit 11 (S 24).

On the other hand, if it is confirmed that the center frequency of the channel set in the cable interface unit 11 is the last center frequency of the channel frequency table, the Annex type set in the demodulator 13 is reset and the next center frequency is set to the first center frequency. Generate a frequency control signal according to (S 25).

That is, if the strength of the cable signal does not maintain a predetermined level, the channel setting unit 15a checks whether the center frequency of the channel set in the cable interface unit 11 is '858 MHz'. Generate an A-annex signal so that (13) can demodulate the cable signal according to the Eurodaxis standard, refer to the channel frequency table, and the first center frequency '93MHz' and the bandwidth of the Eurodaxis standard ' Generate a frequency control signal at 8 MHz '.

The channel setting unit 15A generates and transmits an A anneal setting signal so that the demodulation unit 13 can demodulate the cable signal according to the Eurodaxis standard.

On the other hand, if the center frequency of the channel set in the cable interface unit 11 is not '858 MHz', the channel setting unit 15a refers to the channel frequency table, and the next center frequency '99 MHz 'and the bandwidth' 6 MHz 'are set. Produce according frequency control signal.

The cable interface 11 receives a cable signal through a channel having a center frequency of '93 MHz 'and a bandwidth of' 8 MHz 'according to the frequency control signal generated by the channel setting unit 15a.

On the other hand, when the channel setting unit 15a determines that the strength of the cable signal provided by the tuner 12 maintains a predetermined level, the demodulator 13 demodulates the cable signal transmitted from the tuner according to the set Annex type. , IP packet is converted (S 26).

The channel setting unit 15a then checks whether the FEC and MPEG data of the IP packet demodulated by the demodulator 13 are correct (S27).

As a result of the check, if the FEC and MPEG data are not correct, the channel setting unit 15a checks whether the center frequency of the channel set in the cable interface unit 11 is the last center frequency of the channel frequency table (S 23).

On the other hand, if the FEC and MPEG data are correct as a result of the check, the channel setting unit 15a determines that the IP packet is completely demodulated, and sets the channel set in the cable interface unit 11 as the downstream channel of the cable modem 10. (S 28).

The MAC processor 14 adds the cable MAC header to the IP packet demodulated by the demodulator 13 and transmits the cable MAC header to the controller 15.

The control unit 15 transmits the IP packet transmitted from the MAC processing unit 14 to the communication terminal 20 through the Ethernet interface unit 17 (S 29).

The controller 15 transmits the IP packet transmitted from the communication terminal 20 through Ethernet to the MAC processor 14, and the MAC processor 14 receives the cable MAC header from the IP packet transmitted from the controller 15. Remove it and transmit it to the modulator 18.

The modulator 18 modulates the IP packet in accordance with the Annex type set by the channel setting unit 15a, converts the IP packet into a cable signal, and transmits the cable signal to the cable interface unit 11 (S30).

The cable interface unit 11 transmits the cable signal transmitted from the modulator 18 to the CMTS 2 through the upstream channel corresponding to the downstream channel set by the channel setting unit 15a (S 31).

Although the present invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the present invention, and such modifications and modifications belong to the appended claims.

As described above, according to the present invention, when the cable modem is connected to the cable network, by sequentially scanning the channels according to the Docsis standard and Eurodaxis standard, it is possible to set the channel to automatically receive the cable signal, One cable modem has the effect of accepting both DAXIS and EuroDAXIS specifications.

Claims (19)

In the device for setting the channel of the cable modem, A storage unit for storing at least one channel frequency information according to different standards; The channel is set according to the channel frequency information stored in the storage unit and the bandwidth information according to the cable standard, and the cable signal received through the channel is demodulated by the demodulation method according to the standard. a) if no error occurs in the demodulated packet, set the set channel as a downstream channel of the cable modem, b) an apparatus for setting a channel of a cable modem including a channel setting unit for setting a channel according to next channel frequency information stored in the storage unit when an error occurs in the demodulated packet. The method of claim 1, wherein the cable standard, A device for setting a channel of a cable modem, characterized in that at least one standard of the DOCSIS standard or EuroDOCSIS standard. The method of claim 1 or 2, wherein the storage unit, Device for setting a channel of the cable modem, characterized in that for storing the channel frequency information for each of the standard or Euro-DAX standard, or sequentially storing the channel frequency according to each standard. The method of claim 1 or 2, wherein the channel setting unit, If the channel frequency information is stored for each of the standards in the storage unit, a frequency control signal is generated according to the bandwidth information and the channel frequency information according to the corresponding standard, and if the channel frequency information for each standard is sequentially stored, one When the generation of the frequency control signal using the bandwidth information and the channel frequency information according to the standard of the cable modem, characterized in that for generating a frequency control signal using the bandwidth information and channel frequency information according to the other standard Device to set up. The method of claim 1 or 2, wherein the channel setting unit, If the channel frequency information is stored for each standard in the storage unit, a demodulation setting signal according to the standard is generated. If the channel frequency information for each standard is sequentially stored, the demodulation setting signal according to one standard is generated. And generating a demodulation setting signal according to another standard when the scanning of the channel according to the corresponding standard is completed. delete The method of claim 1, A cable interface unit for setting a channel according to the frequency control signal generated by the channel setting unit and providing a cable signal; A demodulation unit configured to set a demodulation method according to a demodulation setting signal generated by the channel setting unit, and demodulate the cable signal received through the cable interface unit to the set demodulation method and convert the packet signal into a packet; A signal compensator for compensating the cable signal provided by the cable interface unit to a predetermined level and providing the demodulator to the demodulator; A control unit which transmits the demodulated packet to the communication terminal via Ethernet; And a modulator for modulating a packet transmitted from the communication terminal into a modulation scheme corresponding to a demodulation scheme set in the demodulator, and converting the packet to a cable signal. The cable interface unit of claim 1 or 7, And outputting a cable signal modulated by the modulator through an upstream channel corresponding to a downstream channel set by the channel setting unit. The method of claim 1 or 7, wherein the channel setting unit, And checking whether the demodulator of the level of the signal provided by the signal compensator is maintained at the level of a signal that can be demodulated. The method of claim 1, wherein the error of the packet is And an error of forward error correction (FEC) data or motion picture expert group (MPEG) data of the demodulated packet. In the method of setting the channel of the cable modem, Storing at least one channel frequency information according to different standards and storing demodulation scheme information according to each standard; Sequentially setting channels according to the stored channel frequency information and bandwidth information according to a cable standard; Causing the cable signal received through the set channel to be demodulated in a demodulation scheme according to the standard, and if no error occurs in the demodulated packet, setting the set channel as a downstream channel of the cable modem. How to set up a channel for a cable modem. The method of claim 11, Checking whether or not the strength of the received cable signal maintains a predetermined level; if not, setting a channel according to the stored next channel frequency information; If the strength of the cable signal maintains a predetermined level, demodulating the cable signal according to the stored demodulation scheme information and converting the cable signal into a packet; It is determined whether an error has occurred in the packet, and if an error occurs, the channel is set according to the stored next channel frequency information. If the error does not occur in the packet, the set channel is a downstream channel of the cable modem. The method of setting a channel of the cable modem further comprising the step of setting. The method of claim 11, wherein the cable standard, And a channel of a cable modem, characterized in that it is at least one of a dachxis standard or a Eurodaxis standard. The method of claim 11 or 13, wherein the storage of each piece of information, And storing channel frequency information and bandwidth information for each standard, or sequentially storing channel frequency information according to each standard. The method of claim 12 or 13, wherein the setting of the channel according to the next channel frequency information comprises: If the stored channel frequency information is stored for each standard, determining whether the previous channel frequency information is the last channel frequency information stored in the corresponding standard; And setting the channel using the demodulation scheme and the channel frequency information according to another standard when the final channel frequency information of the corresponding standard is determined as the result of the determination. The method of claim 12 or 13, wherein the setting of the channel according to the next channel frequency information comprises: If the stored channel frequency information is sequentially stored, determining whether previous channel frequency information is stored last channel frequency information; And, if the last stored channel frequency is determined, setting a channel using a demodulation scheme according to another standard and stored channel frequency information. In the device for setting the channel of the cable modem, A storage unit for storing channel frequency information according to different standards; A channel controller configured to generate a frequency control signal by using the channel frequency information stored in the storage unit and bandwidth information according to a cable standard, and generate a demodulation setting signal to demodulate the cable signal by a demodulation method according to the standard; A cable interface unit configured to provide a cable signal by setting a channel according to the frequency control signal generated by the channel controller; A demodulation unit for setting a demodulation method according to a demodulation setting signal generated by the channel control unit, demodulating the cable signal received through the cable interface unit into the set demodulation method, and converting the packet signal into a packet; If the cable signal provided from the cable interface unit maintains a predetermined level, it is determined whether an error has occurred in the packet demodulated by the demodulator, and if the error does not occur, the channel set by the cable interface unit is determined. A channel setting unit configured to set a downstream channel of a cable modem and generate a frequency control signal by using the next channel frequency information stored in the storage unit and bandwidth information according to a cable standard when an error occurs. A device that sets the channel of a cable modem. The method of claim 17, A signal compensator for compensating the cable signal provided by the cable interface unit to a predetermined level and providing the demodulator to the demodulator; A control unit which transmits the demodulated packet to the communication terminal via Ethernet; And a modulator for modulating a packet transmitted from the communication terminal into a modulation scheme corresponding to a demodulation scheme set in the demodulator, and converting the packet to a cable signal. In the method of setting the channel of the cable modem, Storing channel frequency information according to different standards and storing demodulation scheme information according to each standard; Setting a channel using the stored channel frequency information and bandwidth information according to each standard, and receiving a cable signal through the set channel; Checking whether or not the strength of the received cable signal maintains a predetermined level; if not, setting a channel according to the stored next channel frequency information; If the strength of the cable signal maintains a predetermined level, demodulating the cable signal according to the stored demodulation scheme information and converting the cable signal into a packet; It is determined whether an error occurs in the packet, c) if an error occurs, setting a channel according to the stored next channel frequency information, d) if no error occurs in the packet, setting the established channel to a downstream channel of the cable modem.

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