KR0153956B1 - Apparatus and method for transmitting multiplex signal of audio/video through aal-5 - Google Patents

Abstract

The present invention relates to an apparatus and method for transmitting multimedia information on an AAL-5 path as a technology necessary for configuring various multimedia terminals in a broadband integrated information communication network.

Accordingly, the present invention multiplexes a video signal by H.261 video coating, a voice signal by G.711, G.722, and G.728 coding, and user data including text and graphic information into a single serial frame. A memory for converting the serial / parallel input / output signals of the H.221 multiplexer / demultiplexer 11 and the H.221 multiplexer / demultiplexer 11 into serial / parallel data and parallel / serial data. 13) a data bus coupled to the memory, a DMAC 16 coupled to the data bus for transferring data in the memory through the use of a bus, a host processor and a main memory 14, 15 coupled to the data bus. It is characterized by including.

Description

Apparatus and method for transmitting audio / visual multiplexed signals over a Type 5 path in an ATM matching layer

1 is a block diagram of an apparatus according to the present invention.

2 is a flowchart of operation according to the present invention.

The present invention relates to an apparatus and method for transmitting H.221 audio / visual multiplexed signals over a Type 5 path in an ATM matching layer.

International standards organizations such as ITU-TS Study Group15 and ATM Forum are currently conducting research for multimedia two-way communication in broadband integrated telecommunication networks. Its main content is an attempt to match ITU-T H.320, a standardized standard of multimedia communication terminals, to a broadband integrated telecommunication network. It mainly attempts to transmit / receive multimedia signals through the path of AAL-1 for the constant bit rate service. It is a trend. However, when a signal is transmitted through the path of AAL-1, an additional additional clock recovery hardware device is required, so that it is possible to interoperate with an existing standard multimedia terminal and to send it on the AAL-5 path. .

In other words, the transmission and reception of H.221 audio / visual multiplexed signals is applied to ISDN synchronous digital networks, and ATM uses structure data transfer (SDT) of AAL-1 to provide a similar operating environment. In addition, the above-mentioned method is under study, such as the H.321 recommendation of ITU-T SG15. Therefore, the transmission and reception of H.221 multiplexed information by AAL-5 rather than AAL-1 has no existing technology or method. However, the H.221 multiplexed signal has advantages in terms of ease of implementation and implementation cost when the AAL-5 path, which is easy to implement hardware, is adopted, compared to a method that requires a separate clock recovery hardware device such as AAL-1. . Therefore, the transmission of H.221 audio / visual multiplexed signals through AAL-5 is a technique that must be implemented.

Accordingly, the present invention relates to an apparatus and method for transmitting multimedia information on an AAL-5 path as a technology necessary for configuring various multimedia terminals in a broadband integrated information communication network.

In order to achieve the above object, the present invention provides a user signal including a video signal by H.261 video coating, a voice signal by G.711, G.722, and G.728 coding, and text and graphic information. H.221 multiplexer / demultiplexer 11 for multiplexing / demultiplexing serial frames and converting serial / parallel input / output signals of the H.221 multiplexer / demultiplexer 11 into serial / parallel data and parallel / serial data. A main memory 12, 13, a data bus coupled to the memory, a DMAC 16 coupled to the data bus, for transferring data in memory through the use of a bus, a host processor and a main memory 14 coupled to the data bus. And 15).

In addition, the present invention is achieved by a processing procedure performed by the operation of the apparatus.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention;

1 is a block diagram of a hardware device according to the present invention.

As shown in the figure, the present invention provides a single serial frame for user data such as video signals based on H.261 video coding, audio signals based on G.711, G.722 and G.728 coding, and text and graphic information. Multiplexing / demultiplexing uses a H.221 multiplexer / demultiplexer 11, a memory 12 for converting these H.221 serial input / output signals into parallel data, and a DMAC 16, via a data bus. The host matching function transferred to the main memory 15 of the processor 14 may be divided into a network matching unit transmitting these information to the ATM network.

In the case of H.221 audio / visual multi-information transmission, the H.221 output stage has the form of serial data, and in order to transmit it through the AAL-5 path through DMAC under the configuration of 1 degree, it must be converted into parallel data. This parallel data is transferred to the main memory under the control of DMAC through the data bus according to the configuration of 1 degree, and the H.221 multiplexed information stored in the main memory is sent to the AAL-5 matching unit of the ATM network junction under the control of DMAC. Type 5 processing is then sent to the ATM network. The signal flow as described above represents the case of transmission and the case of reception corresponds to the reverse order.

The configuration of FIG. 1 showing the configuration according to the present invention shows the components necessary for transmitting and receiving H.221 multiplexing information as described above, and the actual configuration thereof may use the configuration of an existing PC as it is or use a separate processor. The components such as main memory, DMAC, etc. can be connected to a separate system bus under the control of the processor. Therefore, the configuration of FIG. 1 is possible as one method configurable for the transmission and reception of H.221 multiplexed information, and an element of the present invention proposed is a configuration for transmitting and receiving H.221 multiplexed signals in the AAL5 path according to these configuration forms.

The operation of the device according to the present invention, as detailed in the flowchart of FIG. Get assigned. This initial virtual channel may include all of the H.221 multiplexed data of FIG. 1, open a separate virtual channel to divide the multiplexed frames according to the H.221 frame configuration, or multiplex only the video / audio signals to H.221. The data can also be sent by opening a separate virtual channel. In the configuration of the present invention, all three methods are possible, but only the last described video / audio signal is multiplexed in H.221 and sent to the initial virtual channel, and the remaining data is opened in a separate virtual channel. This can be called. That is, most of the data to be sent is created by the user on the host and stored in main memory. When multiplexing to H.221, data in the main memory of the host is sent to the H.221 multiplexer 11 and then brought back to the main memory 15 through the DMAC 16 to have inefficiency. Therefore, the data is initialized through H.242, which is a end-to-end information exchange procedure for end-to-end capability of FIG. 2 to ensure end-to-end interworking with existing H.320-based terminals while using a separate virtual channel. Initialize the H.221 multiplexer 11 to multiplex only the video / audio signal and not use the data.

In this case, since there is no data controller such as a video phone, a terminal that does not use a data path can guarantee end-to-end interworking by the H.242 terminal negotiation procedure. In addition, in ATM networks, various multimedia communication is possible by opening virtual channels for data in addition to these multiplexed signals.

As shown in FIG. 2, an initial virtual channel for video / audio signals is opened and an additional virtual channel is opened for data to secure a path for bidirectional multimedia communication, and the apparatus of FIG. 1 converts H.221 serial data into medical data, The converted parallel data is transferred to the main memory 15 by the DMAC 16. At this time, in addition to the H.221 multiplexed information, the main memory 15 also has data corresponding to user information. The Q.291 multi-network call procedure enables the multimedia signals to be carried on two virtual channels through a packetization process including CRC-32 corresponding to AAL-5 matching processing. (A) indicated by the solid line of FIG. 1 indicates the transmission / reception flow of the video / audio multiplexing signal, and the portion indicated by (b) indicates the transmission / reception flow of the user data. According to the operation sequence described in FIG. 2 in the signal flow of the hardware device as described above, signals of H.320, which is a standard of the existing multimedia communication terminal, are transmitted / received through the AAL-5 matching path of the ATM network. Two-way multimedia communication is possible.

The overall flow of the method according to the invention is explained in detail according to FIG. 2 as follows.

For communication procedures for two-way multimedia communication services such as audio / video and data, the originator of a call establishes an ATM virtual channel in accordance with Q.2931, a broadband call processing procedure, in which the virtual channel has a characteristic of variable bit rate. AAL5 virtual path. After the AAL5 virtual path negotiates the capability with the other terminal according to the H.242 method, which is the end-to-end signaling procedure (22), the other terminal can accommodate a separate AAL5 virtual channel to accommodate the additional service. If there is such a capability, a separate additional channel is connected by the Q2931 procedure described above (23, 24), and which signal should be loaded at which position and how much bandwidth for this additional channel. After negotiating the terminal capability by H.242, which is a negotiation procedure (25), the mode conversion procedure corresponding to the allocation conversion of the band so that multimedia signals such as audio, video, and data can be occupied by the connected bandwidth (26). Go through.

In this case, for example, if a caller uses the AAL5 path of ATM and the other device cannot process data such as a video phone, an additional channel is not required. According to the H.242 negotiation procedure, two-way multimedia communication is started by allocating and multiplexing audio and video signals promised to the H.221 multiplexer / demultiplexer (27). At this time, the output signal of the H.221 part is matched with the data rate so as not to cause problems such as information over-run or under-run that may be lost when transmitting information through the AAL5 path by the serial / parallel buffer buffer shown in FIG. Rate control) function and the parallel output of the buffer buffer is to transmit data through AAL5 path of ATM network matching part under DMA control. On the other hand, when the opposite terminal has a data processing unit, a separate AAL5 virtual channel for data transmission is required separately from the initial channel, in which audio and video are multiplexed in H.221, and thus the end-to-end capability negotiation procedure is followed. Is performed in the same manner as the initial channel mentioned above.

In the reverse order of the procedure for establishing the above-mentioned multimedia communication, if two AAL5 virtual channel paths are used for multimedia communication, the mode switching state can be switched to another communication mode by the mode conversion signal procedure according to H.242. Alternate virtual channels 29 and 30 at 28. If the additional channel is not used for bidirectional communication, the initial virtual channel is switched 31 by the Q.2931 signaling procedure, and the multimedia communication is terminated.

Currently, in order to match H.320 for multimedia communication terminal, which is the only standardized recommendation, to ATM network, there is a matching method through AAL-1, but many additional hardware devices are involved. In order to solve this problem, it is necessary to implement a matching method for transmitting multimedia information through the path of AAL-5, and it is necessary to realize a two-way multimedia communication service in an ATM network in the future. In addition, the AAL-5 path, but also to ensure the end-to-end interoperability with the existing standard multimedia communication terminal as a configuration method for the interworking of various types of terminal cup that will be mixed in various networks in the future. Could be used.

Therefore, this invention has the characteristic which is in charge of the said technical subject.

Claims (2)

H.261 H. Multiplexing / demultiplexing video signals by video coating, audio signals by G.711, G.722, G.728 coding and user data including text and graphic information in a single serial frame. 221 multiplexer / demultiplexer 11 and memories 12 and 13 for converting serial / parallel input / output signals of the H.221 multiplexer / demultiplexer 11 into serial / parallel data and parallel / serial data; A data bus coupled to the data bus, having a DMAC 16 for transferring data in memory through the use of a bus, a host processor and main memory 14, 15 coupled to the data bus. An apparatus for transmitting audio / visual multiplexed signals over a Type 5 path in an ATM matching layer. Video signals by H.261 video coating, G.711, G.722. H.221 multiplexer / demultiplexer 11 for multiplexing / demultiplexing user data including voice signals and text and graphic information by G.728 coding into a single serial frame, and the H.221 multiplexing demultiplexer 11 Memory (12, 13) for converting serial / parallel I / O signals into serial / parallel data and parallel / serial data, a data bus connected to the memory, and a data bus connected to the data bus. Audio / visual multiplexing via a Type 5 path in an ATM matching layer applied to a device having a DMAC 16 for porting, a host processor connected to the data bus and a main memory 14, 15 A method for transmitting a signal, wherein a call originator is a broadband call processing procedure for a communication procedure for a two-way multimedia communication service such as audio / video and data. An ATM virtual channel is established in accordance with 2931, wherein the virtual channel is the AAL5 virtual path having a variable bit rate characteristic and the H.242 method, which is an end-to-end signaling procedure through the AAL5 virtual path. After negotiating the capability with the counterpart terminal, if the counterpart terminal has the capability of accommodating a separate AAL5 virtual channel to accommodate the supplementary service, a second step of connecting a separate supplementary channel; and After the terminal capability negotiation is performed by H.242, which is the end-to-end negotiation procedure of which signal should be loaded at which position and how much bandwidth, accordingly, multimedia signals such as audio, video, and data can be occupied by the connected bandwidth. The third step undergoes a mode conversion procedure corresponding to the allocation conversion of the band to enable the H.221 multiplexing / inverse to the initial virtual channel according to the H.242 negotiation procedure between terminals 4. If two AAL5 virtual channel paths were used for the multimedia communication in the reverse order of the fourth step of allocating and multiplexing the audio and video signals promised to the multiplexer to initiate the two-way multimedia communication, and the procedure for establishing the multimedia communication. A fifth step of switching the additional virtual channels 29 and 30 in the mode switching state 28 capable of switching to another communication mode by the mode switching signal procedure according to 242; and if the additional channel is not used for bidirectional communication. And a sixth step of terminating the multimedia communication by switching the initial virtual channel immediately by the Q.2931 signal procedure.