KR100697974B1 - Apparatus and Method for Multimedia Data Transmission and Receipt in Cable Network using Broadband and Physical Layer based Framing - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to an apparatus for transmitting and receiving multimedia data in a cable network using broadband and physical layer frame structures, and a method for transmitting multimedia data using the same.

2. The technical problem to be solved by the invention

The present invention utilizes a broadband channel capable of transmitting high-speed data in a next-generation cable network, and easily adopts a transmission technology such as a new modulation and demodulation and channel codec to provide an existing cable modem with an existing service from a new cable transmission system. A cable using broadband and physical layer frame structure that provides backward compatibility without disruption and facilitates the introduction of new data transmission services and large capacity data transmission services converged with new communication and broadcasting that will emerge later. An object of the present invention is to provide an apparatus for transmitting and receiving multimedia data in a network and a method of transmitting multimedia data using the same.

3. Summary of Solution to Invention

The present invention provides a multimedia data transmission apparatus in a cable network using a wideband and physical layer frame structure, and matches an external network for transmitting data input / output with an external network to a data over cable service interface specification (DOCSIS) MAC layer. Way; DOCSIS MAC processing means for transmitting data output from the external network matching means to a corresponding destination; First downlink physical layer processing means for processing an existing standard transmission among data output from the DOCSIS MAC processing means; Second downlink physical layer processing means for processing a new wideband transmission of data output from the DOCSIS MAC processing means; And uplink physical layer processing means for transmitting downlink received data to the DOCSIS MAC processing means.

4. Important uses of the invention

The present invention is used in a communication system using a network.

Broadband, Physical Layer Frame, DOCSIS, MAC, Cable Modem (CM), Cable Modem Transmission System (CMTS)

Description

Apparatus and Method for Multimedia Data Transmission and Receipt in Cable Network using Broadband and Physical Layer based Framing}

1 is a diagram illustrating an embodiment of an apparatus for transmitting and receiving multimedia data in a cable network using a broadband and a physical layer frame structure according to the present invention.

2 is a diagram illustrating an embodiment of a channel band used in an apparatus for transmitting and receiving multimedia data according to the present invention.

3 is a block diagram of an embodiment of an apparatus for transmitting and receiving multimedia data according to the present invention;

4 is a block diagram of an embodiment of a multimedia data receiving apparatus according to the present invention;

5 is an exemplary explanatory diagram showing a DOCSIS MAC (MAC) management message structure of a multimedia data transmission apparatus according to the present invention.

FIG. 6 is a diagram illustrating an embodiment of a MAC management message structure of FIG.

7 is a diagram illustrating an embodiment of data transmission using a multimedia data transmission and reception apparatus according to the present invention;

FIG. 8 is a diagram illustrating a basic frame form of a physical layer frame-based downstream transmission structure of a multimedia data transmission device according to the present invention. FIG.

FIG. 9 is an exemplary explanatory diagram illustrating a contiguous physical layer frame structure in which the user data area (Payload) transmission method of FIG. 8 is different; FIG.

FIG. 10 is a diagram illustrating a dynamic operation method using a physical layer frame-based transmission structure of a multimedia data transmission device according to the present invention. FIG.

11 is a diagram illustrating an embodiment of a management message structure for a physical layer frame-based transmission structure of a multimedia data transmission device according to the present invention;

12 is a diagram illustrating an embodiment of a static operation using a physical layer frame-based transmission structure of a multimedia data transmission apparatus according to the present invention.

FIG. 13 is a diagram illustrating an embodiment of a management message structure informing operation information regarding a superframe configuration when a physical layer frame-based transmission structure of a multimedia data transmission device according to the present invention is operated in a static operation mode. FIG.

14 is a diagram illustrating an embodiment of a method of transmitting multimedia data according to the present invention.

15 is a diagram illustrating an extension of a broadband transmission structure of a multimedia data transmission device according to the present invention.

16 is a diagram illustrating an embodiment of a structure of an information message of a wideband channel of a multimedia data transmission apparatus according to the present invention;

* Explanation of symbols for the main parts of the drawings

301: external network 302: existing cable modem data

303: New Cable Modem Data 304: Cable Modem Transmission System

305: network matching unit 306: DOCSIS MAC processing unit

307: existing downlink physical layer unit 308: new downlink physical layer unit

309: Lookup Table 310: Upward Physical Layer

311: additional broadband 312: existing service band

313: existing cable modem 314: existing downlink physical layer receiver

315: DOCSIS MAC 316: uplink physical layer transmitter

317: User Device 318: New Cable Modem

319: existing downlink physical layer receiver 320: new downlink physical layer receiver

321: uplink physical layer transmitter 322: DOCSIS MAC

323: user device

The present invention uses a wideband channel capable of transmitting high-speed data in a next-generation cable network, and uses a wideband and physical layer frame structure that can easily adopt and use transmission techniques such as new modulation and demodulation and channel codecs. The present invention relates to a media data transmission and reception device and a method of transmitting multimedia data using the same, and more particularly, backward compatibility so that an existing cable modem (CM) can receive existing services from a new cable transmission system. The present invention relates to a multimedia data transmission and reception apparatus using a broadband and physical layer frame structure and a multimedia data transmission method using the same to facilitate the introduction of new communication broadcast convergence services and new technologies that will emerge in the future.

Currently, cable modem transmission systems (CMTS) and cable modems (CM) complying with the "Data Over Cable Service Interface Specification (DOCSIS) 1.0, 1.1, and 2.0" standard for transmitting data using a cable network are widely used.

In the existing Data Over Cable Service Interface Specification (DOCSIS) standard, the RF bandwidth that can be transmitted downstream is limited to 6 MHz. That is, the cable modem (CM) can receive data in one 6MHz band, the maximum transmission rate is about 40Mbps. However, with the emergence of various types of services in which communication and broadcasting are converged, the currently used standard shows a limitation in service provision capability and efficiency.

The DOCSIS downstream transmission specification was developed in the early 90's, and as new hardware emerges and hardware performance improves, the introduction of new physical layers is not only easy to introduce new services but also effective to provide existing services. It is accepted. However, a major consideration in introducing new technologies is that cable service subscribers should not be prevented from providing new services within the allowable range as well as existing services provided by the introduction of new technologies. In other words, it should be a structure that supports backward compatibility.

In addition, with the development of cable transmission technology, various types of cable modems may exist together in the same cell. Here, the various forms may be a reception capability of a cable modem (CM) capable of supporting a new standard when a transmission method using a cable network is newly standardized with the development of technology, or a cable modem ( The optimal transmission method that can be used due to different reception environments of CM) may be different. In consideration of these newly developed transmission standards and environments, when allocating additional transmission bands to each group to provide a transmission method suitable for each cable modem (CM) group, there is a limit to the frequency resources that can be used in the cable network. . In the future, when a new standard requires compatibility as a requirement, a new receiver has a problem in that an additional cost is required to implement a physical layer for receiving an existing band.

In order to solve this problem, various methods have been tried since 2000, such as change of modulation and demodulation scheme, introduction of high-efficiency channel coding scheme, and change of transmission structure.

The present invention has been proposed to solve the above problems, using a broadband channel capable of transmitting high-speed data in the next-generation cable network, and easily adopts a transmission technique such as a new modulation and demodulation and channel codec, thereby making the existing cable modem new. It provides backward compatibility so that it does not interfere with the existing service from the cable transmission system, and facilitates the introduction of new data transmission services and large-capacity data transmission services incorporating new communications and broadcasting. An object of the present invention is to provide an apparatus for transmitting and receiving multimedia data in a cable network using a broadband and physical layer frame structure and a method for transmitting the multimedia data using the same.

Other objects and advantages of the present invention can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. Also, it will be readily appreciated that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the claims.

The apparatus of the present invention for achieving the above object is a multimedia data transmission apparatus in a cable network using a broadband and physical layer frame structure, the data input and output to and from the external network DOCSIS (MAC MAC) External network matching means for transmitting to the layer; DOCSIS MAC processing means for transmitting data output from the external network matching means to a corresponding destination; First downlink physical layer processing means for processing an existing standard transmission among data output from the DOCSIS MAC processing means; Second downlink physical layer processing means for processing a new wideband transmission of data output from the DOCSIS MAC processing means; And uplink physical layer processing means for transmitting uplink received data to the DOCSIS MAC processing means.

In addition, another apparatus of the present invention is a multimedia data receiving apparatus in a cable network using a wideband and physical layer frame structure, comprising: a first downlink physical layer receiving means for receiving a conventional physical layer scheme; Second downlink physical layer receiving means for receiving a wideband physical layer scheme; DOCSIS MAC processing means for processing data received by the first downlink physical layer receiving means and the second downlink physical layer receiving means; And uplink physical layer transmission means for transmitting uplink transmission data.

Meanwhile, in the method of the present invention, a multimedia data transmission method in a cable network using a broadband and physical layer frame structure, an external network matching module extracts an Ethernet frame from a packet input from an external network or an internal server. A Mac frame configuration and storage step of constructing a DOCSIS MAC frame and storing the DOCSIS MAC frame in a DOCSIS MAC frame buffer; A transport channel classification step of classifying the DOCSIS MAC frame stored in the MAC frame configuration and storage into an existing service channel or a broadband transport channel according to a transmission destination address; In the transport channel classification step, the frames classified as the broadband transport channels are classified according to the physical layer transmission method set in each cable modem (CM), and the DOCSIS MAC packet classified as the broadband channel transmission is MPEG-2 (MPEG-). 2) classifying and storing a MAC frame for a wideband transport channel, which is mapped to a transport stream (TS) and stored in a first MPEG-2 transport stream (TS) buffer for each transmission scheme; In the transport channel classification step, a MAC frame for transmitting a packet or a management message classified into an existing service band is mapped to an MPEG-2 transport stream (TS) and transmitted to an existing service band. Classifying and storing a MAC frame for an existing transport channel to store in a 2 MPEG-2 transport stream (TS) buffer; Wideband transmission channel modulated by the physical layer frame-based modulator by transmitting the packet stored in the MAC frame classification and storage step for the broadband transmission channel according to the operation scheme and bandwidth allocation policy of the physical layer frame-based transmission structure set by the transmission controller Modulation step; And an existing transport channel modulation step of modulating a stored packet in the MAC frame classification and storage step for the existing transport channel.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, whereby those skilled in the art may easily implement the technical idea of the present invention. There will be. In addition, in describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram illustrating an embodiment of an apparatus for transmitting and receiving multimedia data in a cable network using a broadband and physical layer frame structure according to the present invention. When a new transmission scheme is introduced, FIG. 1 illustrates a transmission using an optical coaxial mixed network (HFC). A conceptual diagram is shown.

The basic concept of the apparatus for transmitting and receiving multimedia data using the broadband channel according to the present invention is newly defined along with the transmission of physical layer signals based on "DOCSIS (Data Over Cable Service Interface Specification) 2.0" based on the existing service for providing existing services. The broadband signal is transmitted at the same time.

The cable modem transmission system (CMTS) is a basic physical layer transport channel conforming to "ITU-T J.83 Annex B" and the new broadband structure physical layer, depending on whether the cable modem supports wideband transmission at the MAC layer. This is a method of transmitting data by selecting a channel to transmit from the channels. Therefore, the cable modem (CM) used by the existing user is provided with the service through the physical layer conforming to the existing standard, and the new cable modem (CM) is provided with the service through both the existing physical layer and the new physical layer. To make it possible. In addition, the transmission for the new broadband is to transmit in the form suitable for the emergence of new standards or various optimal reception environment of the cable modem (CM) using a physical layer frame-based downstream transmission structure.

A cable modem transmission system that supports the new transmission method when the new transmission method is introduced to provide a new service while including an existing service using an optical coaxial mixed network (HFC) 102 or for more efficient transmission ( CMTS) 101 and a new cable modem (CM) 103 need to be installed. However, the cable modem (CM) 103, 105 at the subscriber end corresponding to the new cable modem transmission system (CMTS) 101 supports only the existing standard as well as the cable modem (CM) 103 supporting the new standard or scheme. The cable modem (CM) 105 is present together. At this time, a user who does not have a new cable modem (CM) 103 should be able to receive the service provided through the existing cable modem (CM) 105 without any limitation. And new services should be available to existing users to the extent that the performance of the existing cable modem (CM) allows. In other words, backward compatibility should be provided.

2 is a diagram illustrating an embodiment of a channel band used in an apparatus for transmitting and receiving multimedia data according to the present invention, and shows a DOCSIS 1.x / 2.0 and an additional wideband downstream transmission band configuration for a wideband channel transmission structure.

The basic concept of a transmission structure using a broadband channel is to simultaneously use a DOCSIS 1.x / 2.0 based downstream physical layer 201 and a newly defined new wideband physical layer 202 to provide an existing service. It is. At this time, the cable modem transmission system (CMTS) is a new physical layer transmission channel 201 and the new physical layer according to the "ITU-T J.83 Annex B" according to whether the cable modem (CM) support broadband transmission in the MAC layer (MAC) A channel to be transmitted is selected from the physical layer channel 202 of the broadband structure to transmit data to the cable modem CM. That is, the existing cable modem (CM) may be provided with a service through a physical layer conforming to the existing standard, and the new cable modem may be provided with a service through both the existing physical layer and the new physical layer.

A user with an existing cable modem (CM) may not only be provided with the existing service through the existing physical layer and the existing channel, but may receive a new service within the transmission capability of the existing physical layer.

Users with a new cable modem (CM) can be provided with various types of services using the transmission efficiency and transmission capabilities of the new physical layer.

The existing downlink service band 201 uses "ITU-T J.83 Annex B" defined in the DOCSIS standard as a band allocated in units of 6 MHz, and a management message for setting whether to provide a new downlink service is transmitted through this band. do.

The newly added broadband can be allocated arbitrary broadband to allow operators to use the channel more efficiently, without the limitation of the existing 6MHz band, and the allocated broadband enables video on demand (VOD) and high-speed data to many users. It can effectively provide various services that could not be provided in the 6MHz band such as transmission. In this case, although the bandwidth of the broadband is allocated in multiples of 6 MHz may provide convenience in operation, it is not necessarily a multiple of 6 MHz. Signals transmitted over broadband can be used by adopting new physical layer transmission technologies such as 1024 quadrature amplitude modulation (QAM), low density parity check (LDPC), and mixed modulation and demodulation, which are not currently adopted in the standard.

3 is a block diagram of an embodiment of an apparatus for transmitting and receiving multimedia data according to the present invention, illustrating a concept of transmission and reception for an additional wideband channel transmission structure.

The apparatus for transmitting and receiving multimedia data using the existing service band 312 and the additional broadband 311 according to the present invention includes a new cable modem transmission system (CMTS) 304 supporting the existing downlink physical layer and the new broadband downlink physical layer. ), A new cable modem (CM) 318 supporting the existing downlink physical layer and the new broadband downlink physical layer, and a conventional cable modem (CM) 313 supporting only the existing downlink physical layer.

The cable modem transmission system (CMTS) 304 supporting the new broadband scheme includes an external network matching unit 305 for transmitting data input and output to and from the external network to the DOCSIS MAC layer, and at the external network matching unit 305. DOCSIS MAC processing unit 306 for transmitting the output data to a corresponding destination, an existing downlink physical layer unit 307 for processing an existing standard transmission among data output from the DOCSIS MAC processing unit 306, the New downlink physical layer unit 308 for processing new wideband transmission among data output from DOCSIS MAC processing unit 306 and uplink physical layer unit for transmitting the received data to DOCSIS MAC processing unit 306. 310.

The external network matching unit 305 transmits data input / output with an external network such as an IP backbone network or a VOD server to the DOCSIS MAC layer.

The DOCSIS MAC processing unit 306 of the cable modem transmission system (CMTS) 304 performs a function of supporting the downlink wideband physical layer in addition to the existing DOCSIS MAC processing function. To this end, when the data received from the external network or the head end service providing apparatus is the data 302 which is the existing cable modem (CM) 313, the user data and the management message data are transferred to the existing downlink physical layer unit ( 307, and if the destination of the data transmission is a new cable modem (CM) 318, all user data is transmitted via the broadband 311 using the new downlink physical layer portion 308.

For management messages between the cable modem transmission system (CMTS) 304 and the cable modem (CM) 313, 318, except for user data sent to the new cable modem (CM) 318, the cable modem transmission system (CMTS) The DOCSIS MAC processing unit 306 of 304 transmits using the existing downlink physical layer unit 307 or transmits both to the existing downlink physical layer unit 307 and the new downlink physical layer unit 308.

In this case, when the management message is transmitted by using the existing downlink physical layer unit 307, the user data and the management message data are separately transmitted in the case of the management data. This is because the management message can be efficiently processed by transmitting all management messages between the system (CMTS) 304 and the cable modem (CM) 313 and 318 using one physical layer. If the management message is transmitted to both the existing downlink physical layer unit 307 and the new downlink physical layer unit 308, the existing cable modem (CM) 313 is later upgraded to the new cable modem (CM) 318. When it is done, there is an advantage of not using the existing band.

Unlike the management data, the user data is one physical layer and transmission band defined by the DOCSIS MAC processing unit 306 of the cable modem transmission system (CMTS) 304 according to the destination of the cable modem (CM) 313 and 318. In this case, the user data is separated into two channels and is not transmitted, thereby eliminating the process of separating and recombining the user data, thereby simplifying the processing at the MAC layer of the cable modem (CM) 313 and 318. .

The new cable modem (CM) 318 capable of supporting broadband includes an existing downlink physical layer receiver 319 capable of receiving an existing physical layer scheme, and a new downlink physical layer receiver 320 capable of receiving a broadband physical layer. , A DOCSIS MAC processor 322, and an uplink physical layer transmitter 321.

The DOCSIS MAC processor 322 of the new cable modem (CM) 318 may process both data transmitted from the existing physical layer and data transmitted from the new broadband physical layer.

Existing service band 312, as mentioned above, if the management message sent to the new cable modem (CM) 318 is also transmitted to the broadband transport channel at the same time, the existing cable modem (CM) 313 is all new When upgraded to cable modem (CM) 318 may no longer transmit signals to the existing service band. However, even after all existing cable modem (CM) 313 is upgraded, the existing service band 312 is managed and signaled in addition to the data transmitted to the user through the entire optical coaxial mixed network (HFC) in addition to maintaining backward compatibility. It can be used as a dedicated channel for.

Currently, in a cable network, a signaling channel in the form of a separate OOB (Out Of Band) or DSG (DOCSIS Settop Gateway) exists for a digital broadcast service. In the case of the DOCSIS channel, a management message is transmitted through each downlink channel. However, rather than managing and signaling data transmitted through a separate channel for all services, transmitting all signaling data through one dedicated channel to process at the terminal can effectively provide a service in which broadcasting and communication are converged. .

4 is a block diagram of an embodiment of a multimedia data receiving apparatus according to the present invention.

As shown in FIG. 4, the apparatus for receiving multimedia data according to the present invention includes a physical layer module such as a tuner 401 and a demodulator 402 for receiving an existing service band, and a tuner for receiving a new wideband signal. 404 and a physical layer module such as a demodulator 405, MAC frame extractors 403 and 406 for extracting DOCSIS MAC frames from the MPEG-2 transport stream, and a DOCSIS MAC (MAC) layer processing unit 407.

The demodulated signals in the demodulators 402 and 405 from the existing service band and the new broadband service band are output in the form of MPEG-2 transport stream (TS), and the MPEG-2 transport stream (TS). DOCSIS MAC frames are extracted by the MAC frame extractors 403 and 406 and input to the DOCSIS MAC processing unit 407.

The receiving device first obtains information on the additional broadband channel from the existing service band. Based on the information on the obtained wideband channel, the receiver determines whether the wideband channel is available, and if available, sets the shape information 408 of the tuner 404 and the demodulator 405 for the new service band, and the wideband channel. Receive user data via.

5 is a diagram illustrating an embodiment of a DOCSIS MAC (MAC) management message structure of a multimedia data transmission device according to the present invention.

MAC management message is a message for network operation such as initialization, registration and band allocation between the cable modem transmission system (CMTS) and the cable modem (CM) in the MAC layer used in the cable network. Control) DOCSIS MAC header is added to the frame type to have a final DOCSIS MAC frame type.

DOCSIS MAC (MAC) management messages include DOCSIS MAC (MAC) headers, DOCSIS MAC (MAC) management message headers, DOCSIS MAC (MAC) management message payloads and Cyclic Redundancy Check (CRC).

The DOCSIS MAC header consists of "FC", "MAC PARM", "LEN" and "HCS", where the first two bits of the "FC" field are always "11" to indicate management messages, not user data.

DOCSIS MAC management message headers include destination address (DA), source address (SA), message length (message length from DSAP to Payload), DSAP (set to 0x00), and SSAP (set to 0x00). ), Control (set to 0x03), Version and Type (Version & Type: Management Message Version and Type between Cable Modem Transmission System (CMTS) and Cable Modem (CM)), and RSVD (Reserved).

Management messages In the Payload data portion, messages for DOCSIS MAC management are defined.

The CRC is a code for error detection of a message and calculates a payload including headers such as a destination address (DA) and a source address (SA).

FIG. 6 is an exemplary diagram illustrating a MAC management message structure of FIG. 5.

The cable modem transmission system (CMTS) determines if any cable modem (CM) includes the ability to use the new physical layer and broadband when the cable is first activated or restarted.

In the initialization of the cable modem CM, the signaling between the cable modem transmission system CMTS and the cable modem CM is determined. In this case, the signaling message between the cable modem transmission system CMTS and the cable modem CM may be downlinked. It may be transmitted using a physical layer and a band. Thereafter, the cable modem transmission system (CMTS) can provide new physical layer and broadband information periodically in accordance with the DOCSIS MAC management message standard, as shown in FIG. 6, to enable more efficient broadband operation. have.

The broadband channel management message may include information about the center frequency, transmission band, modulation format, modulation rate, and channel coding format for the allocated broadband.

The information displayed in FIG. 6 is interpreted by the MAC layer processor 407 of the receiver to set the shape information 408 of the tuner 404 and the demodulator 405 for receiving a new service band.

FIG. 7 is a diagram illustrating an example of data transmission using a multimedia data transmission and reception apparatus according to the present invention, and shows an example of configuring a transmission network using an optical coaxial mixed network (HFC).

When configuring a transmission network using the optical coaxial mixed network (HFC) 702, various types of cable modem (CM) (704, 705, 706) may exist together in the same cell (703). Here, the various forms may be a reception capability of a cable modem (CM) capable of supporting a new standard when a transmission method using a cable network is newly standardized with the development of technology, or a cable modem ( The optimal transmission method that can be used due to different reception environments of CM) may be different. In this case, transmission methods that can be used by the cable modem CM from the same cable modem transmission system (CMTS) 701 may be various forms such as "A", "B", and "C". Here, the cable modems (CMs) of the "A", "B", and "C" groups have different transmission schemes that can be used in additional broadband channels. In order to provide a transmission scheme for each group in consideration of such a reception environment, there is a limit to the frequency resources that can be used in a cable network when allocating transmission bands to each group. In addition, when a new scheme is introduced, the new receiver is additionally required to implement a physical layer for receiving an existing band. Therefore, there is a need for an effective transmission method for cable modems (CMs) that can efficiently accommodate the existing schemes and those that will be introduced later, and each have a reception environment.

8 is a diagram illustrating an embodiment of a basic frame form of a physical layer frame-based downstream transmission structure of a multimedia data transmission device according to the present invention.

The physical layer frame-based downstream transmission structure transmits data for a certain time by physically framing the transmission data for a certain time to effectively support a transmission method suitable for various reception environments of a new modem or various cable modem (CM) as a single broadband transmission band. That's the way it is.

The transmission frame of the physical layer includes a start pattern (Preamble) 801 indicating the start of a frame, physical layer information (PLI) 803 indicating a transmission method of the physical layer frame, and a user data area (Payload). 802.

In the physical layer frame-based transmission structure, transmission schemes such as modulation and demodulation schemes and channel coding of the start pattern 801 and the physical layer transmission information (PLI) 803 are fixed, so that the receiver can receive them without any additional information. However, the transmission method of the user data region (Payload) 802 may vary in units of frames of the physical layer.

FIG. 9 is a diagram illustrating an embodiment of a continuous physical layer frame structure in which the user data area (Payload) transmission method of FIG. 8 is different.

The frame length may vary from frame to frame, but the transmission rate is the same for each frame regardless of the transmission method, and is continuously transmitted (901). Therefore, the demodulator can maintain timing synchronization with respect to the symbols of the modulated signal. In this case, the transmission method of the user data portions (Payload) 902 to 904 may vary for each physical layer frame.

For example, the physical layer transmission scheme of the user data region of one frame at any point of time is 64QAM and RS incubation scheme (902), and the 256QAM and 7/8 LDPC code encoding scheme (903) in the next physical layer frame. Can be. Since the transmission scheme for the physical layer may vary from frame to frame, information on the transmission scheme for each physical layer frame must be transmitted to the receiver in advance. Therefore, the information on each physical layer transmission scheme may be given in the physical layer transmission information (PLI) in the frame before the previous frame or several frames in consideration of the reception capability of the receiver.

FIG. 10 is a diagram illustrating a dynamic operation using a physical layer frame-based transmission structure of a multimedia data transmission device according to the present invention.

The physical layer frame-based transmission structure can be operated in two ways.

One of them is a dynamic operation method in which the transmission method of the physical layer is changed every frame.

In the dynamic operation method, since the transmission method is changed for each frame, the receiver should be informed of the transmission method information about the frame in real time.

Information on the transmission method for the frame to be received may be displayed in the physical layer transmission information (PLI) field of the physical layer frame, and depending on the length and transmission speed of the frame, "the information about the transmission method should be informed in advance. Do you do it? "

The dynamic operation scheme of FIG. 10 is a form in which information about a transmission scheme of a currently transmitted user data region is informed one frame before (1001). However, this value may vary depending on the system implementation.

The length of each physical layer frame may vary in units of physical layer frames.

In FIG. 10, the total number of symbols of the physical layer frame of the "transmission method 1" 1002 is "s (1)", and the "transmission method-2" 1003 has the number of s (2) symbols.

11 is a diagram illustrating an embodiment of a management message structure for a physical layer frame-based transmission structure of a multimedia data transmission device according to the present invention.

When the transmission structure for the new service band of FIG. 1 is configured with the physical layer frame-based structure shown in FIG. 9, the information about the physical layer frame structure and the transmission scheme of FIG. 11 is shown in FIG. 1. It is transmitted in the form of DOCSIS management message payload 1101 through the band.

The management message for the physical layer frame-based frame structure includes basic information such as the frequency 1102 and the bandwidth 1103 for an additional channel together with the operation method 1104 and the number of transmission methods 1105 of the physical layer frame-based frame structure. And information 1106 for each transmission scheme.

The information 1106 for each transmission scheme includes a version 1107 indicating a change in transmission scheme information, the number of symbols 1108 per physical layer frame of the corresponding transmission scheme, and information (1109, 1110) for modulation and coding schemes. Included.

12 is a diagram illustrating an embodiment of a static operation using a physical layer frame-based transmission structure of a multimedia data transmission device according to the present invention.

In the static operation method, a superframe 1205 of a large unit is configured and operated by allocating a required number of frames 1204 for each transmission method 1201, 1202, and 1203 of each user data area (Payload).

Information on the super frame 1205 is transmitted in the form of a DOCSIS management message as shown in FIG. 13 through the existing service channel band 201 of FIG. 2.

In FIG. 12, superframes have transmission schemes for k different user data areas (Payloads), and are composed of physical layer frames by n (1),..., N (k) for each transmission scheme. Here, n (k) represents the number of physical layer frames of the transmission scheme k.

In the case of the static operation method, the transmission method and the number of frames of each method are preset in units of superframes, and information on this method is transmitted in advance, so that physical layer transmission information on the user data area transmitted in each physical layer frame in FIG. (PLI) 803 may not be included.

FIG. 13 is an exemplary view illustrating a management message structure informing operation information regarding a superframe configuration when a physical layer frame-based transmission structure of a multimedia data transmission device according to the present invention is operated in a static operation mode.

The management message 1301 regarding the superframe configuration for the static operation includes a serial number 1302, the total number of physical layer frames 1303 in the superframe, the number of transmission schemes used 1304, and each transmission scheme 1306. Information about the physical layer frame number 1305).

The serial number 1302 in the management message regarding the super frame configuration changes every time the superframe configuration is changed. If the receiver receives the same serial number as the previously received management message, the receiver receives the management message. Ignore

If the configuration of the superframe is changed during operation, information on the configuration change of the superframe is transmitted to the receiver in the form of a management message before the management message of the superframe is changed.

FIG. 14 is a diagram illustrating an embodiment of a method of transmitting multimedia data according to the present invention and shows a downstream transmission process for physical layer frame-based transmission using a wide band.

Packets input to the external network or from the internal server are extracted from the IEEE 802.3 Ethernet frame by the external network matching module 1401, constituted as DOCSIS MAC frames (1402), and placed in the DOCSIS MAC frame buffer. Stored.

Each DOCSIS MAC frame refers to the reception information table 1405 received from the registration information between the cable modem (CM) and the cable modem transmission system (CMTS) in the initialization phase of the cable modem (CM) according to the transmission destination address. It is classified as an existing service channel or a broadband transport channel (1403). In addition, the frame classified as a broadband transmission channel is classified according to the physical layer transmission method set in each cable modem (CM) (1404), and at this time, the cable modem and the cable modem transmission in the initialization stage of the cable modem CM. The reception information table 1405 received from the registration information between the systems CMTS is used.

DOCSIS MAC packets classified as wideband channel transmissions are mapped to MPEG-2 transport streams (1406) and MPEG-2 transport streams (TS) for each transmission scheme. Are stored in buffers 1407, 1408, and 1409.

A MAC frame that transmits a packet classified into an existing service band or a management message 1413 is mapped to an MPEG-2 transport stream (TS) as in the existing DOCSIS 1.x / 2.0 (1414). And then stored in an MPEG-2 transport stream (TS) buffer 1415 for transmission in the existing service band.

The QAM modulator 1416 for the existing service band 201 continuously reads and transmits packets in the MPEG-2 transport stream (TS) buffer 1415.

If there is no packet in the MPEG-2 transport stream (TS) buffer 1415, an empty packet is inserted, and the modulation scheme for the existing service band is "ITU-T J.83 Annex B".

In case of physical layer frame-based transmission for the wideband channel 202, packets stored in the MPEG-2 transport stream (TS) buffers 1407, 1408, and 1409 corresponding to each transmission scheme are physical layer frame-based modulation. When output to the unit 1411, the transmission control unit 1412 is transmitted according to the operation scheme and band allocation policy of a physical layer frame-based transmission structure preset. That is, the transmission control unit 1412 determines a policy for dynamic / static operation in advance and transmits it according to the determined operation mode.

In the dynamic operation illustrated in FIG. 10, a buffer of a transmission method to be output is selected by using buffer status and quality of service (QoS) information of each transmission method. And a transmission mode for the MPEG-2 transport stream (TS) packet output in the current physical layer frame and a transport for the MPEG-2 transport stream (TS) packet to be transmitted in a subsequent frame. The method is set in the physical layer frame-based modulator 1411 so that the additional channel modulator may configure a frame according to the physical layer frame structure to output a modulated signal.

In the static operation illustrated in FIG. 12, the transmission control unit 1412 selects the MPEG-2 transport stream (TS) buffers 1407, 1408, and 1409 of the transmission method to be output according to the configuration information of the preset superframe. In addition, the physical layer frame-based modulator 1411 configures a physical layer frame for static operation to transmit a modulation signal.

15 is a diagram illustrating an extension of a broadband transmission structure of a multimedia data transmission device according to the present invention.

In addition to the use of two transmission channels as shown in FIG. 2, the structure for improving the transmission rate by adding a band can be extended to a plurality of transmission channels as shown in FIG. That is, the cable modem CM may receive additional multiple bands in addition to the basic compatible channel. In this case, when the cable modem (CM) is initially initialized using the basic backward compatible channel as described above, the terminal may determine information about the additional band and the number of broadbands to be used, and the cable modem transmission system (CMTS) and the cable modem (CM). It is set in advance through a management message defined between them. In this case, the additional bands may be any band as well as the existing 6MHz band.

16 is a diagram illustrating an embodiment of a structure of an information message of a wideband channel of a multimedia data transmission apparatus according to the present invention.

The information message of the wideband channel can be easily shaped by extending the current standard DOCSIS management message. The transmission method in each wideband channel may be a transmission method other than one. Therefore, the information on the transmission scheme for each broadband channel is transmitted in the form of management messages through the backward compatible channel.

As described above, the method of the present invention may be implemented as a program and stored in a recording medium (CD-ROM, RAM, ROM, floppy disk, hard disk, magneto-optical disk, etc.) in a computer-readable form. Since this process can be easily implemented by those skilled in the art will not be described in detail any more.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the technical spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by the drawings.

As described above, the present invention provides backward compatibility so that the existing cable modem is provided with the existing service from the cable transmission system that is developed for the introduction of the new service. This is easy, and there is an effect that can be used as a transmission method and apparatus for the next-generation cable network that can provide a converged communication and broadcasting service.

Claims (22)

In the multimedia data transmission apparatus in a cable network using a broadband and physical layer frame structure, External network matching means for transmitting data input and output to and from an external network to a DOCSIS (MAC) layer; DOCSIS MAC processing means for transmitting data output from the external network matching means to a corresponding destination; First downlink physical layer processing means for processing an existing standard transmission among data output from the DOCSIS MAC processing means; Second downlink physical layer processing means for processing a new wideband transmission of data output from the DOCSIS MAC processing means; And Uplink physical layer processing means for transmitting uplink received data to the DOCSIS MAC processing means Multimedia data transmission device comprising a. The method of claim 1, The DOCSIS MAC processing means, In addition to the existing DOCSIS MAC processing function, it can support the downlink wideband physical layer, and when transmitting data received from an external network or a service providing device in a headend, the destination is a conventional cable modem (CM). In case of data, user data and management message data are transmitted using the first downlink physical layer processing means, and when the destination of data transmission is a new cable modem (CM), all user data is transferred to the second downlink physical layer processing means. Multimedia data transmission device, characterized in that for transmitting over a broadband. The method of claim 2, The management message data, Transmitted from the DOCSIS MAC processing means using the first downlink physical layer processing means, or transmitted to both the first downlink physical layer processing means and the second downlink physical layer processing means, and used in the cable network. This is a message for network operation including initialization, registration, and bandwidth allocation between a transmitting device and a receiving device at a MAC layer, and a DOCSIS MAC header is added to a LLC (Logical Link Control) frame form. (MAC) frame type, characterized in that it comprises a DOCSIS MAC header, DOCSIS MAC (MAC) management message header, DOCSIS MAC (MAC) management message payload and CRC (Cyclic Redundancy Check) Multimedia data transmission device. The method of claim 3, wherein The DOCSIS MAC header is Multimedia data transmission device comprising "FC", "MAC PARM", "LEN" and "HCS", wherein the first two bits of the "FC" field are always "11" to indicate that it is a management message rather than user data. . The method of claim 3, wherein The DOCSIS MAC management message header, Destination Address (DA), Source Address (SA), Message Length (Message Length from DSAP to Payload), DSAP (Set to 0x00), SSAP (Set to 0x00), Control (Set to 0x03) Version & Type (Version & Type: Management message version and type between the cable modem transmission system (CMTS) and the cable modem (CM)), and multimedia data transmission device comprising a RSVD (Reserved). The method of claim 3, wherein The DOCSIS MAC management message payload, A device for managing DOCSIS MAC in a data portion, wherein the multimedia data transmission device comprises information on a center frequency, a transmission band, a modulation format, a modulation rate, and a channel coding format. The method of claim 3, wherein The user data, Multimedia data transmission apparatus according to the existing or new cable modem (CM) is transmitted through one physical layer and a transmission band determined by the DOCSIS MAC processing means. An apparatus for receiving multimedia data in a cable network using a broadband and a physical layer frame structure, First downlink physical layer receiving means for receiving an existing physical layer scheme; Second downlink physical layer receiving means for receiving a wideband physical layer scheme; DOCSIS MAC processing means for processing data received by the first downlink physical layer receiving means and the second downlink physical layer receiving means; And Uplink physical layer transmission means for transmitting uplink transmission data Multimedia data receiving device comprising a. The method of claim 8, The first downlink physical layer receiving means, First tuning means for receiving an existing service band; First demodulation means for demodulating data output from the first tuning means; And First MAC frame extracting means for extracting DOCSIS MAC frames from MPEG-2 transport stream data output from the first demodulation means; Multimedia data receiving device comprising a. The method of claim 9, The second downlink physical layer receiving means, Second tuning means for receiving a new wideband signal; Second demodulation means for demodulating data output from the second tuning means; And Second MAC frame extracting means for extracting DOCSIS MAC frames from the MPEG-2 transport stream data output from the second demodulation means; Multimedia data receiving device comprising a. The method according to any one of claims 8 to 10, The multimedia data receiving device, The first additional information about the additional wideband channel is obtained from the existing service band, based on the information on the obtained wideband channel to determine the availability of the wideband channel, and if available, the second tuning means for the new service band and And after the shape information of the second demodulation means is set, user data is received through a wideband channel. In the multimedia data transmission method in a cable network using a broadband and physical layer frame structure, A MAC frame configuration and storage step of extracting an Ethernet frame by an external network matching module from a packet input from an external network or an internal server, configuring a DOCSIS MAC frame, and storing the Ethernet frame in a DOCSIS MAC frame buffer; A transport channel classification step of classifying the DOCSIS MAC frame stored in the MAC frame configuration and storage into an existing service channel or a broadband transport channel according to a transmission destination address; In the transport channel classification step, the frames classified as the broadband transport channels are classified according to the physical layer transmission method set in each cable modem (CM), and the DOCSIS MAC packet classified as the broadband channel transmission is MPEG-2 (MPEG-). 2) classifying and storing a MAC frame for a wideband transport channel, which is mapped to a transport stream (TS) and stored in a first MPEG-2 transport stream (TS) buffer for each transmission scheme; In the transport channel classification step, a MAC frame for transmitting a packet or a management message classified into an existing service band is mapped to an MPEG-2 transport stream (TS) and transmitted to an existing service band. Classifying and storing a MAC frame for an existing transport channel to store in a 2 MPEG-2 transport stream (TS) buffer; Wideband transmission channel modulated by the physical layer frame-based modulator by transmitting the packet stored in the MAC frame classification and storage step for the broadband transmission channel according to the operation scheme and bandwidth allocation policy of the physical layer frame-based transmission structure set by the transmission controller Modulation step; And Existing transport channel modulation step of modulating the stored packet in the MAC frame classification and storage step for the existing transport channel Multimedia data transmission method comprising a. The method of claim 12, The MAC frame classification and storage step for the wideband transport channel, And a reception information table received from registration information between the cable modem (CM) and the cable modem transmission system (CMTS) during the initialization of the cable modem (CM). The method of claim 12, The MAC frame classification and storage step for the existing transport channel, And if there is no packet in the second MPEG-2 transport stream (TS) buffer, inserting an empty packet. The method of claim 12, The wideband transport channel modulation step, In the case of dynamic operation, the buffer of the transmission method to be output is selected by using the buffer status and the quality of service (QoS) information of each transmission method, and the MPEG-2 transport stream (output in the current physical layer frame) The transmission mode for the TS) packet and the transmission method for the MPEG-2 transport stream (TS) packet to be transmitted in a subsequent frame are set in the physical layer frame-based modulator to add an additional channel modulator to the physical layer frame. The frame is configured according to the structure so that the modulated signal can be output, and in case of static operation, the transmission control unit transmits the first MPEG-2 (MPEG-2) of the transmission method to be output according to the configuration information of the preset superframe. Selecting a stream (TS) buffer, the physical layer frame-based modulator to configure a physical layer frame for static operation to transmit the modulated signal, characterized in that How to send TIM media data. The method of claim 12, The existing transport channel modulation step, "ITU-T J.83 Annex B" is applied as a modulation scheme for the existing service band, and the QAM modulator for the existing service band is a packet in the second MPEG-2 transport stream (TS) buffer. And continuously reading and transmitting the multimedia data. The method according to any one of claims 12 to 16, The physical layer frame structure, In order to effectively support the transmission method suitable for various reception environments of the cable modem (CM) or the future in a single broadband transmission band, the transmission data for a certain time is physical layer framed, and the physical layer transmission frame is used to start the frame. And a physical layer information (PLI) for displaying a transmission pattern of a physical layer frame, a user data region, and a payload. The method of claim 15, The dynamic operation, In this way, the transmission method of the physical layer is changed for each frame, and the receiver informs the transmission method information of the frame in advance, and the information on the transmission method for the frame to be received is indicated in the physical layer transmission information (PLI) field of the physical layer frame. The method of claim 7, wherein the information about the transmission method is informed before the preset frame according to the length and the transmission speed of the frame. The method of claim 18, The dynamic operation, It has a management message, the management message is transmitted in the form of a DOCSIS management message payload through the existing service channel band, and the operation method of the physical layer frame-based frame structure, along with basic information including the frequency and bandwidth for the additional channel, transmission The number of schemes and information on each transmission scheme are included, and the information on each transmission scheme includes a version indicating a change in transmission scheme information, the number of symbols per physical layer frame, modulation and demodulation and coding scheme of the corresponding scheme. Multimedia data transmission method comprising the. The method of claim 15, The static operation, It is a method of configuring and operating a large unit of superframe by allocating a required number of frames for each user data area (payload) transmission method. The information on the superframe is transmitted in the form of DOCSIS management message through an existing service channel band. Multimedia data transmission method characterized in that. The method of claim 20, The superframe, There is a transmission method for a predetermined number of different user data areas (Payload), and each transmission method is composed of a predetermined number of physical layer frames, the management message for the super frame configuration is a serial number, the total in the super frame Information on the number of physical layer frames, the number of transmission schemes used, and the number of physical layer frames for each transmission scheme is included. The serial number in the management message regarding the superframe configuration is changed whenever the configuration of the superframe is changed. If the serial number of the received management message is the same as the serial number of the previously received management message, the receiver ignores the management message.If the configuration of the superframe is changed during operation, the receiver changes the superframe before changing the management message of the superframe. The information on the configuration change is transmitted to the receiver in the form of a management message. Multimedia data transmission method. The method of claim 17, The multimedia data transmission method, It is possible to expand to multiple transmission channels, and the cable modem (CM) receives additional multiple bands in addition to the basic compatible channel, and information about the additional bands and the number of widebands to be used are determined using the basic backward compatible channel. And when the cable modem (CM) is initially initialized, it is set in advance through a management message defined between the cable modem transmission system (CMTS) and the cable modem (CM).

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