KR20120064742A - Headend apparatus and video processing for cable network - Google Patents

Abstract

PURPOSE: A head-end apparatus for cable network and a video processing method are provided to economically process various types of video service flows flowing into a head-end using the miniaturized head-end apparatus. CONSTITUTION: A head-end apparatus for cable network comprises the following: an M-CMTS(modular-cable modem termination system)(112) outputting a video stream based on the DOCSIS(data over cable service interface specification); a video processing unit(200) processing one of the video stream selected from the video stream based on the DOCSIS, a MPEG-2 TS video stream, or a video stream on IP(internet protocol) network; and a cable modem(130) receiving the processed video stream using HFC(hybrid fiber-coaxial) network(120).

Description

Headend devices and video processing on cable networks {HEADEND APPARATUS AND VIDEO PROCESSING FOR CABLE NETWORK}

TECHNICAL FIELD The present invention relates to cable networks, and more particularly to headend devices and video processing of cable networks.

Broadband connection technologies such as cable, fiber optics, and wireless are widely deployed. In communication networks between subscribers and service providers, providing reliable high quality voice / video services is not an easy task.

Cable networks include cable modems, headends, and cable modem termination systems (CMTS). For uplink transmission, the cable modem modulates the digital stream into an uplink radio frequency (RF) signal. For downlink reception, the cable modem demodulates in digital form from the received downlink RF signal. The CMTS in the headend of the cable network demodulates the downlink digital stream into a downlink RF signal. Downlink / uplink RF signals are transmitted over optical and coaxial lines.

The Data Over Cable Service Interface Specification (DOCSIS) defines a standard interface protocol for cable modems. DOCSIS discloses Open Systems Interconnection (OSI) layers 1 and 2, the physical layer and data link layer, and the DOCSIS 3.0 specification was released in April 2006.

In a hybrid fiber-coaxial (HFC) -based network, digital video services are modulated into RF signals in the form of MPEG-2 transport stream (TS) packet streams from the service provider's video server through the edge-quadrature amplitude modulation (EQAM) of the HFC network. And transmitted to the subscriber.

Most existing video transmission services are video broadcasting services based on broadcast transmission schemes. Thus, one program is broadcast to the subscriber cell per one frequency channel of the cable network. Recently, however, a variety of video such as multicast video transmission services such as Switched Digital Video (SDV) services, which provide video services only to limited subscriber groups, and user-demand services such as video on demand (VOD) and video conferencing Transmission methods are emerging. In addition, the DOCSIS standard, which is a data transmission standard, is gradually pursuing a large capacity to accommodate not only data but also VoIP and IP-based video service flows, so that the service flow form for video transmission is more diverse.

Decentralized processing using both expensive DOCSIS equipment and frequency devices for video transmission to accommodate video service flows coming through these various types of cable networks can be costly.

Compared to frequency transmission equipment such as EQAM, which is a conventional cable network transmission device, data processing equipment M-CMTS (Modular-CMTS) is expensive and very high performance and large equipment, and it is used to accommodate various video service flows. This is because equipping all of them requires a lot of investment in network construction.

There is a need for a technique that can efficiently transmit various video service flows.

The present invention provides a flow switched headend device and video processing of a cable network.

In one aspect, a headend device of a cable network is provided. The headend device is a modular-cable modem termination system (M-CMTS) that outputs a data over cable service interface specification (DOCSIS) based video stream, and the DOCSIS based video stream, an MPEG-2 TS video stream, and an Internet Protocol (IP). A video processing apparatus for processing at least one of the video streams on the network to transmit to the cable modem through the HFC (Hybrid Fiber-Coaxial) -based network.

The video processing apparatus exchanges a DOCSIS frame module for converting a video stream on the IP network into a DOCSIS frame, and a flow exchange for exchanging service flows for each of the DOCSIS frame, the DOCSIS-based video stream, and the MPEG-2 TS video stream. It may include a module.

The video processing apparatus may further include a transmission module for converting the video stream output from the flow exchange module into a physical frequency transmission signal for transmission on the HFC based network.

The transmission module may include DEPI EQAM based on DEPI (DOCSIS External PHY Interface) and video EQAM based on MPEG2-TS.

The DOCSIS frame module may pass the DOCSIS-based video stream and the MPEG-2 TS video stream.

In another aspect, a video processing apparatus device of a cable network is provided. The video processing apparatus includes a DOCSIS frame module for converting a video stream on an Internet Protocol (IP) network into a DOCSIS frame, and a DOCSIS (Data Over Cable Service Interface Specification) output from the DOCSIS frame and a modular-cable modem termination system (M-CMTS). Flow exchange module for exchanging service flows for each of the < RTI ID = 0.0 >) video streams < / RTI > It includes.

In another aspect, a method of video processing of a cable network is provided. The method includes converting a video stream on an Internet Protocol (IP) network into a DOCSIS frame, and a data over cable service interface specification (DOCSIS) based video output from the DOCSIS frame and a modular-cable modem termination system (M-CMTS). Exchanging service flows for each of the stream and the MPEG-2 TS video stream.

Various types of video service flows entering the head end of the cable network can be processed using more economical and compact devices. The proposed video processing device can be implemented in the form of a preprocessor for a physical frequency transmission device and can be compatible with the transmission device of an existing network.

1 is a block diagram illustrating an HFC cable network system according to an embodiment of the present invention.
2 is a block diagram illustrating a video processing apparatus according to an embodiment of the present invention.
3 is a block diagram illustrating a video processing apparatus according to another embodiment of the present invention.
4 shows an example of video stream processing.
5 shows another example of video stream processing.
6 shows another example of video stream processing.

The proposed invention relates to an apparatus and method for transmitting a switched video stream for switching and transmitting digital video data streams transmitted in various forms in a hybrid fiber-coaxial (HFC) based cable network.

Hereinafter, various video service flows inputted through an MPEG-2 transport stream (TS) based transmission scheme as well as an IP (Internet Protocol) transmission scheme or a DOCSIS (Data Over Cable Service Interface Specification) based packet stream may be converted into DOCSIS frames, or An apparatus for transmitting over a frequency channel of a cable network according to a delivery attribute of a video service flow output through a flow exchange is proposed.

1 is a block diagram illustrating an HFC cable network system according to an embodiment of the present invention.

An external source 110 provides a video service stream from the service provider, such as a video server and / or public TV streamer, to the headend 110.

The headend 110 includes a Modular-Cable Modem Termination System (M-CMTS) 112 and a video processing device 200. The M-CMTS 112 receives data packets and / or video packets from an external source 100, converts them into DOCSIS-based frames, and outputs the converted data packets.

The video processing apparatus 200 receives a video service flow and performs flow switching. The downlink stream output by the video processing apparatus 200 is provided to a cable modem (CM) 130 through the HFC network 120.

There are various types of video service flows flowing into the video processing apparatus 200 in the headend 110. Incoming video service flows are IP based DOCSIS data flow 11 to be transmitted through CMTS 112, DOCSIS video service flow 12 flowing through CMTS 112, and MPEG using Layer 2 Tunneling Protocol (L2TP). -2 TS video service flow 13, and MPEG-2 TS video service flow 14, which flows directly through the IP network.

The video processing apparatus 200 processes DOCSIS frames according to types of service flows to receive and output various types of video service flows or modulates them into appropriate frequency channels according to flow exchange functions. Accordingly, subscribers can receive not only IP-based video playback but also data services and video broadcast services through one integrated cable network resource.

2 is a block diagram illustrating a video processing apparatus according to an embodiment of the present invention.

The video processing apparatus 200 includes a video flow preprocessor 210 and a transmission module 220.

The video flow preprocessor 210 includes a DOCSIS frame module 212 and a flow switching module 214.

The DOCSIS frame module 212 converts the IP video stream 14 input through the IP network into a frame based on DOCSIS.

The flow exchange module 214 uses the frame output from the DOCSIS frame module 212, the MPEG2-TS video stream 13, and the DOCSIS-based video stream 12 to perform DOCSIS service flow according to a corresponding medium access control (MAC) protocol. Form.

The flow exchange module 214 transmits the MPEG-2 TS video service flow 14 and the MPEG-2 TS video service flows 12 and 13 over IP through timing and multiplexing processes for the corresponding flows according to flow types. Send to module 220. The flow exchange module 214 analyzes the header of the input stream and exchanges service flows according to the service flow type of the stream.

The transmission module 220 may be referred to as a physical frequency transmission device. The output of the transmission module 220 is a frequency channel transmission signal that is output according to the Downstream RF interface (DRFI) standard through the frequency channel.

The transmission module 220 may include a DOCSIS External PHY Interface (DEPI) EQAM 222 and a video EQAM 224. DEPI EQAM 222 is a DEPI based EQAM and video EQAM 224 is an MPEG2-TS based EQAM.

For the DEPI EQAM 222, data encapsulation is performed using two DEPI tunneling techniques.

In DOCSIS Packet Stream Protocol (D-PSP), video streams are encapsulated in DOCSIS MAC format or data packets. DOCSIS frames are sent in the L2TP tunnel payload. In DOCSIS MPEG Transport Stream (D-MPT), the video stream is encapsulated into DOCSIS MAC frames, and the DOCSIS MAC frames are encapsulated into MPEG2-TS packets. Multiple MPEG2-TS packets are sent in an L2TP tunnel payload.

Video EQAM 224 processes the MPEG2-TS stream with DOCSIS PID (Program ID). Single Program Transport Stream (SPTS) and / or Multi Program Transport Stream (MPTS) may be processed.

3 is a block diagram illustrating a video processing apparatus according to another embodiment of the present invention. In comparison with the embodiment of FIG. 2, the video processing apparatus 300 includes the video flow preprocessor 210 of FIG. 2. The video processing apparatus 300 includes a DOCSIS frame module 212 and a flow exchange module 214. The transmission module may be disposed separately in the headend.

The video processing apparatus 300 provides a video stream as an interface in the form of a DOCSIS frame-based service flow and / or an MPEG-2 TS service flow. The output of the video processing device 300 is connected to the input of an independent physical frequency transmission device such as the transmission module 220 of FIG. 2.

Now, the procedure for processing the video stream for each service flow will be described in more detail.

4 shows an example of video stream processing. This means that content such as a video stream is directly input to the video processing apparatus 200 over the IP network without passing through the CMTS.

Service flows input over the IP network may include various content types, such as video stream 410 and VoIP / data packet 420. The input service flow is converted into DOCSIS service flow by the DOCSIS frame module 212. The converted DOCSIS service flow is input to DEPI EQAM 222 or video EQAM 224.

The output of DEPI EQAM 222 or video EQAM 224 is transmitted as a DOCSIS signal to CM 450 and provided to subscriber 460.

5 shows another example of video stream processing. This represents a process of processing the MPEG-2 TS video stream flowing into the video processing apparatus 200 over the IP network.

The MPEG-2 TS video service flow 402 on the IP network is input to the video processing apparatus 200. Since the incoming video stream does not require DOCSIS frame processing, the DOCSIS frame module 212 bypasses. The video EQAM 224 performs MPEG-2 TS timing processing and multiplexing processing on the input stream. The stream output from the video EQAM 224 is provided to the subscriber's set-top box (STB) 560 via the cable network 550.

6 shows another example of video stream processing. The video processing apparatus 200 processes a data packet 610 and a video packet 620 and 630 converted into a DOCSIS stream by CMTS or M-CMTS.

 Since the M-CMTS has already processed the frequency channel and transmission schedule to be used for DOCSIS frame conversion and transmission for the corresponding service flow, the DOCSIS frame module 212 of the video processing apparatus 200 passes.

The input DOCSIS service flow is input to DEPI EQAM 222 or video EQAM 224 after a flow exchange is performed. The service flows output from the DEPI EQAM 222 or the video EQAM 224 are all in the form of DOCSIS service flows and have their own PIDs 641 and 642 according to their transmission schedules.

The output of DEPI EQAM 222 or video EQAM 224 is transmitted as a DOCSIS signal to CM 650 and provided to subscriber 660.

As described above, the proposed flow-switched video processing apparatus is a video service flow processing apparatus having a simple and miniaturized functional unit, and accommodates various types of video service flows, thereby minimizing / simplifying the components of the head end of the cable network. can do. The flow-switched video processing device can be implemented in the form of a preprocessor for the EQAM frequency transmission device by itself and can be compatible with existing devices in the network.

This saves the economic cost of the headend of a cable network previously configured with EQAM.

It is expected that the integrated video service flow processing will be able to provide more flexible service of the cable network.

The above-described embodiment may be implemented by a processor. The processor may comprise an application-specific integrated circuit (ASIC), other chipset, logic circuitry and / or a data processing device. The memory may include read-only memory (ROM), random access memory (RAM), flash memory, memory cards, storage media, and / or other storage devices. The RF unit may include a baseband circuit for processing a radio signal. When the embodiment is implemented in software, the above-described techniques may be implemented with modules (processes, functions, and so on) that perform the functions described above. The module is stored in memory and can be executed by the processor. The memory may be internal or external to the processor and may be coupled to the processor by any of a variety of well known means.

In the above-described exemplary system, the methods are described on the basis of a flowchart as a series of steps or blocks, but the present invention is not limited to the order of the steps, and some steps may occur in different orders or simultaneously . In addition, those skilled in the art will appreciate that the steps shown in the flowcharts are not exclusive and that other steps may be included or one or more steps in the flowcharts may be deleted without affecting the scope of the present invention.

Claims (11)

In the headend device of a cable network,
A modular-cable modem termination system (M-CMTS) for outputting a data over cable service interface specification (DOCSIS) based video stream; And
And a video processing apparatus for processing at least one of the DOCSIS-based video stream, an MPEG-2 TS video stream, and a video stream on an Internet Protocol (IP) network and transmitting the same to a cable modem through a HFC (Hybrid Fiber-Coaxial) -based network. Headend device characterized in that. The method of claim 1,
The video processing device
A DOCSIS frame module for converting a video stream on the IP network into a DOCSIS frame; And
And a flow exchange module for exchanging service flows for each of the DOCSIS frame, the DOCSIS-based video stream, and the MPEG-2 TS video stream. The method of claim 2,
The video processing device
And a transmission module for converting the video stream output from the flow exchange module into a physical frequency transmission signal for transmission on the HFC based network. The method of claim 3, wherein
The transmission module includes a DEPI EQAM based on DEPI (DOCSIS External PHY Interface) and a video EQAM based on MPEG2-TS. The method of claim 2,
And the DOCSIS frame module passes the DOCSIS-based video stream and the MPEG-2 TS video stream. A video processing apparatus device of a cable network,
A DOCSIS frame module for converting a video stream on an Internet Protocol (IP) network into a DOCSIS frame; And
Each service flow is exchanged by exchanging service flows for each of the DOCSIS frame, a Data Over Cable Service Interface Specification (DOCSIS) based video stream output from a modular-cable modem termination system (M-CMTS), and an MPEG-2 TS video stream. And a flow exchange module for causing the video stream corresponding to the to be transmitted to the cable modem through a HFC (Hybrid Fiber-Coaxial) based network. The method according to claim 6,
And a transmission module for converting the video stream output from the flow exchange module into a physical frequency transmission signal for transmission on the HFC based network. The method of claim 7, wherein
The transmission module includes a DEPI EQAM based on DEPI (DOCSIS External PHY Interface) and a video EQAM based on MPEG2-TS. The method according to claim 6,
And the DOCSIS frame module passes the DOCSIS-based video stream and the MPEG-2 TS video stream. In the video processing method of the cable network,
Converting a video stream on an Internet Protocol (IP) network into a DOCSIS frame; And
Exchanging service flows for each of the DOCSIS frame, a Data Over Cable Service Interface Specification (DOCSIS) based video stream output from a modular-cable modem termination system (M-CMTS), and an MPEG-2 TS video stream. Video processing method. 11. The method of claim 10,
And transmitting the video stream corresponding to each service flow to a cable modem through a HFC (Hybrid Fiber-Coaxial) based network.

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