KR101200493B1 - Terminal Transmission Apparatus for Multimedia Service via Satellite Link and Method for providing multimedia service via satellite link - Google Patents

Abstract

Divide the input broadcast IP data into Internet and TV data and Voice (VoIP) data, and encode Internet and TV data that allows long delay time according to the existing DVB-S2 standard. The allowable voice data is encoded in 4K mode based on the DVB-RCS + M standard. The coded data is orthogonally modulated, and the orthogonal modulated speech data is spread by band based on a direct sequence according to a spreading factor. The spread signal is multiplexed so as to overlap the frequency allocated to each user in the form of frequency division multiple access (FDMA).

Description

Terminal Transmission Apparatus for Multimedia Service via Satellite Link and Method for providing multimedia service via satellite link}

The present invention relates to a terminal transmission apparatus capable of providing a multi-media service through a satellite communication link and a multi-media service providing method using the same. More specifically, an IP-based satellite broadcast service and a satellite Internet service through a satellite communication link are provided. The present invention relates to a terminal transmission device for providing a satellite VoIP service and a multi-media service providing method using the same.

The present invention is derived from a study conducted as part of the IT growth engine technology development project of the Korea Communications Commission [Task Management Number: 2007-S-008-03, Task name: 21GHz band satellite broadcasting transmission technology development].

At present, many technologies for providing a multimedia service using a satellite communication link have been developed. For example, in Europe, satellite broadcasting is provided through the DVB-S2 (Digital Video Broadcasting-Satellite-Second Generation) standard, and satellite Internet services are provided through the DVB-RCS (Digital Video Broadcasting-Return Channel via Satellite) standard. It is possible. In addition, depending on the availability (availability) of the satellite link, the QoS level, and the performance of the terminal device, it is possible to support satellite IPTV service and satellite VoIP service through the DVB-RCS standard. This is because the DVB-RCS standard itself is designed to support IP-based multimedia services. The DVB-RCS standard initially targeted fixed services, but now the DVB-RCS + M standard can also support mobile services.

In particular, in the case of satellite communication can be serviced to the area that the terrestrial network signal does not reach, multimedia services using satellite links can also be serviced in the air, sea, island mountains. However, in case of satellite communication, the round trip delay time is large, and the delay factor of service occurs because of processing delay time of low-density parity-check (LDPC) decoding of DVB-S2 standard.

Satellite broadcasting and internet services have a somewhat lower requirement for real time, but voice services such as VoIP are a very constrained service due to the active interactive services.

To overcome this problem, the DVB-RCS + M standard makes efforts to reduce the delay factor by creating 4K frame specifications for each user return link.

SUMMARY OF THE INVENTION The present invention has been made in the technical background as described above, and an object of the present invention is to provide a terminal transmission apparatus capable of providing a multi-media service through a satellite communication link.

Another object of the present invention is to provide a method for transmitting a broadcast broadcast triple play and a terminal transmission device for providing a satellite VoIP service in addition to a satellite IPTV service and a satellite Internet service.

It is still another object of the present invention to provide a terminal transmission apparatus capable of providing a voice (VoIP) service capable of maintaining a service quality in a band used for a conventional satellite IPTV service and a satellite Internet service and operating at low QoS. It is.

In order to solve such a problem, the present invention provides a method for including voice (VoIP) information by spreading a band without securing an additional band in a band used for a conventional satellite IPTV service and a satellite Internet service, and terminal transmission using the same. Provide a device.

According to an aspect of the present invention, there is provided a multi-media service terminal transmission apparatus that separates input IP data into first data allowing a delay time above a predetermined reference value and second data allowing a delay time below the reference value. A first encoder for performing low-density parity-check (LDPC) encoding on the first data, a first modulator for performing quadrature modulation on an output of the first encoder, and a second encoder for LDPC encoding on the second data. And a second modulator for orthogonally modulating the output of the second encoder, a spreader for spreading the output of the second modulator with an orthogonal code, and a multiplexer for multiplexing the output of the first modulator and the output of the spreader. It is done by

Here, the first data may be satellite Internet service data or satellite IPTV service data, and the second data may be satellite VoIP service data.

Preferably, the second encoder LDPC encodes the second data to have a delay element smaller than that of the output of the first encoder. The first encoder uses DVB-S2 standard, and the second encoder uses DVB. -4K mode based on RCS + M specification is available.

The spreader spreads the output of the second modulator on a direct sequence basis according to a predetermined spreading factor, and the multiplexer spreads the signal spread by the spreader using a single-channel per-carrier (SCP) frequency division. In the form of multiple access, each user may be multiplexed so as to overlap the frequency allocated to each user.

According to another aspect of the present invention, there is provided a method for providing a multi-media service, comprising: separating input IP data into first data allowing a delay time above a predetermined reference value and second data allowing a delay time below the reference value; A first encoding step of performing low-density parity-check (LDPC) encoding of the first data, a first modulation step of performing orthogonal modulation on an output of the first encoding step, and a second encoding of LDPC encoding of the second data And a second modulation step of orthogonally modulating the output of the second encoder, band spreading the output of the second modulation step with an orthogonal code, outputting the output of the first modulation step and the output of the diffusion step. Multiplexing.

According to the present invention, it is possible to transmit voice information using an existing frequency band without additionally allocating a new band in the bands used for the existing satellite IPTV service and the satellite Internet service. play) service.

In addition, since a service is provided through spread spectrum for a voice service signal, it is possible to provide a service that satisfies a desired QoS level while improving frequency efficiency.

1 is a block diagram showing the function of a DVB-S2 system used for data modulation in a multi-media service terminal transmission apparatus according to an embodiment of the present invention.
2 is a block diagram illustrating a method of modulating Internet and TV data and voice data in a multi-media service terminal transmission apparatus according to an embodiment of the present invention.
3 shows an example of a signal multiplexed for each user by a multi-media service terminal transmission apparatus according to an embodiment of the present invention.

Advantages and features of the present invention, and methods of achieving the same will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. It is noted that the terms "comprises" and / or "comprising" used in the specification are intended to be inclusive in a manner similar to the components, steps, operations, and / Or additions.

According to the present invention, it is possible to provide a multi-functional multimedia service through a satellite link based on a physical layer waveform of the DVB-RCS + M standard.

Currently, the DVB-RCS + M standard uses the DVB-S2 transmission standard on the forward link and the reverse link, and uses the 4K frame standard in the reverse link SCPC (Single Channel Per Carrier) mode. The reason for using the 4K frame standard is to reduce the processing delay time of the LDPC code. In addition, the DVB-RCS + M specification specifies a direct sequence-based spread spectrum technology.

According to the present invention, in addition to the IPTV service and the satellite Internet service that can be realized through the satellite link based on the DVB-RCS + M standard, the existing satellite broadcasting and the Internet use the VoIP-based voice service through the satellite link. Provided through spread spectrum in.

1 is a block diagram showing the function of a DVB-S2 system used for data modulation in a multi-media service terminal transmission apparatus according to an embodiment of the present invention.

As shown in FIG. 1, IP data 110 inputted to a multi-media service terminal transmission apparatus according to an embodiment of the present invention is converted into TS (Transport Stream) data 120 through a Multi Protocol Encapsulation (MPE) process. . The TS data 120 is again converted into a baseband frame (BB) frame 130 based on the DVB-S2 / RCS standard, and the frame is converted into a forward error correction (FEC) frame 140. Alternatively, the IP data 110 may be directly converted into a baseband (BB) frame 130 through a GSE (Generic Protocol Encapsulation) process.

At this time, the Internet service, the IPTV service, and the voice service are modulated in different ways according to the PID (Process IDentifier) according to each service in the step of converting the BB frame 130 to the FEC frame 140. That is, Internet service and IPTV service that allow relatively long delay time are inputted to existing DVB-S2 modulator, and voice service that allows relatively short delay time because of two-way service is 4K mode based on DVB-RCS + M standard. Is entered.

As described above, a process of separating and encoding data is illustrated in FIG. 2.

As shown in FIG. 2, when the communication broadcast convergence IP data 240 is input, the Internet and TV data allowing a long delay time are input to the existing DVB-S2 LDPC encoder 150, and a short delay is performed. The voice data allowing time only is input to the 4K mode LDPC encoder 250 based on the DVB-RCS + M standard. The encoded Internet and TV data and audio data are orthogonally modulated by the DVB-S2 modulators 160 and 260, respectively, and the orthogonal modulated speech data is input to the DVB-RCS spreader 270 to minimize interference between users. The band spread is performed according to a spreading factor using.

In more detail, the modulation signal completed until the pulse shaping according to the DVB-S2 orthogonal modulation becomes a signal in the unit of symbols through the matching filter again, and spreads the spectrum based on the direct sequence based on the spreading coefficient.

Next, the spread signal is multiplexed so as to overlap with the frequency allocated to each user in the form of frequency division multiple access (FDMA).

3 shows an example of a signal multiplexed to overlap the frequency allocated to each user.

In FIG. 3, the thin line is a signal provided to the first user, the thick line is a signal provided to the second user, the dashed line is an internet and TV data signal, and the dashed line is an audio signal. Indicates.

That is, as shown in Figure 3, it is possible to increase the frequency efficiency by using the existing frequency band without allocating a new band. However, in this case, interference may occur between users. As a method for minimizing interference, a spreading factor may be increased and a user may use interference mitigation signal processing technology at a receiving end. In addition, since the spread spectrum signal is a voice service signal, the QoS level is low so that it can be easily satisfied.

Although the present invention has been described above with reference to preferred embodiments, the multi-media service terminal transmission apparatus and the multi-media service providing method of the present invention are not necessarily limited to the above-described embodiments, and various modifications may be made without departing from the spirit and scope of the invention. Modifications or variations are possible. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit of the invention.

Claims (12)

A data separation unit for separating the input IP data into first data allowing a delay time above a predetermined reference value and second data allowing a delay time below the reference value;
A first encoder configured to low-density parity-check (LDPC) encoding the first data;
A first modulator for orthogonally modulating the output of the first encoder;
A second encoder for performing LDPC encoding on the second data;
A second modulator for orthogonally modulating the output of the second encoder;
A spreader for spreading the output of the second modulator with an orthogonal code;
A multiplexer for multiplexing the output of the first modulator and the output of the spreader for each user,
And the multiplexer multiplexes the signals spread by the spreader to overlap frequencies allocated to each user in the form of single-channel per-carrier (SCPC) (frequency division multiple access (FDMA)). The method of claim 1,
The first data is satellite internet service data or satellite IPTV service data,
And the second data is satellite VoIP service data. The method of claim 1,
And the second encoder LDPC-encodes the second data to have a delay element smaller than that of the output of the first encoder. The method of claim 1,
The first encoder uses the DVB-S2 standard,
The second encoder is a multi-media service terminal transmission apparatus using a 4K mode based on the DVB-RCS + M standard. The method of claim 1,
And the spreader spreads the output of the second modulator based on a direct sequence based on a predetermined spreading factor. delete Dividing the input IP data into first data allowing a delay time above a predetermined reference value and second data allowing a delay time below the reference value;
A first encoding step of low-density parity-check (LDPC) encoding the first data;
A first modulation step of orthogonally modulating the output of the first encoding step;
A second encoding step of LDPC encoding the second data;
A second modulation step of orthogonally modulating the output of the second encoder;
Spreading the output of the second modulation step with an orthogonal code;
Multiplexing the output of the first modulation step and the output of the spreading step by user;
And in the multiplexing step, multiplexing a signal spread through the spreading step so as to overlap a frequency allocated to each user in the form of single-channel per-carrier (SCP). The method of claim 7, wherein
The first data is satellite internet service data or satellite IPTV service data,
And the second data is satellite VoIP service data. The method of claim 7, wherein
And in the second encoding step, LDPC encoding the second data to have a delay element smaller than that of the output of the first encoding step. The method of claim 7, wherein
The first encoding step uses a DVB-S2 standard, and the second encoding step uses a 4K mode based on the DVB-RCS + M standard. The method of claim 7, wherein
And in the spreading step, spread the output of the second modulation step on a direct sequence basis according to a predetermined spreading factor. delete

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