KR100430563B1 - LMD's Headend System Using Broadband-CDM - Google Patents

Abstract

The present invention implements a headend system of an LMDS located in a CATV broadcasting station in an LMDS using a wideband-CDMA (W-CDMA) scheme to provide interactive CATV, satellite broadcasting, and video on demand. The head-end system of LMDS using W-CDMA method which can perform wireless LMDS digital service such as VOD), Internet, telephone, etc. W-CDMA baseband processing, QAM modulation of ATM data such as VOD, Internet, telephone, etc., converted to RF signal of 28GHz frequency band for transmission to each cell site, and on the contrary, CATV, satellite broadcasting, VOD, Internet at cell site When ATM data such as a telephone or the like is transmitted, a receiver converts the ATM data into an IF signal of 950 to 2050 MHz, QPSK demodulates it, and extracts the ATM data through CDMA baseband processing. It characterized in that the transmission to.

Description

Head-end system of LMDS using Broadband-CDMA

The present invention relates to a CATV broadcasting station in a local multipoint distribution system (hereinafter referred to as "LMDS") using a broadband-code division multiple access (WDMA) method. Wireless LMDS digital such as interactive CATV (CAble TeleVision), satellite broadcasting, video on demand (hereinafter referred to as "VOD"), Internet, telephone, etc. by implementing LMDS's headend system. The present invention relates to a head-end system of LMDS using a W-CDMA scheme capable of performing a service.

Recently, LMDS has adopted a wireless access communication method using W-CDMA to perform various LMDS digital services such as two-way CATV, satellite broadcasting, and VOD.

In other words, the LMDS adopting the W-CDMA method is a system that provides a multi-channel, two-way wireless digital CATV service using the W-CDMA method using a frequency band of 27.5 to 29.5 GHz. Provides interactive services such as internet and phone.

In particular, since the LMDS uses W-CDMA, it maximizes channel capacity and performs stable communication.

As described above, as the LMDS using the W-CDMA method is emerging, the LMDS headend system located in a CATV broadcasting station may be implemented to provide wireless LMDS digital services such as two-way CATV, satellite broadcasting, VOD, Internet, and telephone. There is a need.

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and its object is to provide a wireless LMDS digital service such as two-way CATV, satellite broadcasting, VOD, Internet, telephone, etc. It is to provide a head-end system of LMDS using.

The head-end system of the LMDS using the W-CDMA method of the present invention to achieve the above object, W-CDMA basis for ATM data, such as CATV, satellite broadcasting, VOD, Internet, telephone, etc. Band-processed, QAM-modulated, converted into RF signal of 28 GHz frequency band to be transmitted to each cell site. On the contrary, when ATM data such as CATV, satellite broadcasting, VOD, Internet, telephone are transmitted from cell site, The ATM data is converted into an IF signal of 950 to 2050 MHz, QPSK demodulated, and the ATM data is extracted and transmitted to the ATM switch through W-CDMA baseband processing.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration and operation of the head-end system of the LMDS using the W-CDMA method according to the present invention.

1 is a block diagram of a head-end system of an LMDS using the W-CDMA method according to the present invention. The satellite receiver receives data from various formats and converts it into MPEG-2TS (Transmission Stream), which is ATM multiplexed. Receive telephone and communication data by matching the head-end unit 10, the VOD server unit 20 that provides the video program data, and the Public Switched Telephone Network (PSTN) / Packet Switched Data Network (PSDN). A transcoder / communication matching unit 30, an internet matching unit 40 matching with the internet network to receive internet data, the headend unit 10, a VOD server unit 20, a transcoder ATM switch 50 for switching head-end image data, telephone and communication data, Internet data, etc. output from the communication matching unit 30 and the Internet matching unit 40 into AT'M data and switching the ATM switch 50; Is connected to 50 and the VOD server unit 20 A level 1 gateway 60 for providing a VOD menu and signaling processing of the VOD menu, and an operation maintenance unit 70 connected to the ATM switch 50 to perform network management and operation maintenance; After receiving the ATM data such as VOD, satellite broadcasting, Internet, telephone and data output from the ATM switch 50, performing W-CDMA baseband processing and digital modulation, and then converting them into RF signals of 28 GHz band. Converts and transmits the cell data to a cell site (not shown), converts ATM data transmitted from the cell site into an intermediate frequency (IF) signal, performs digital demodulation and W-CDMA baseband processing, and then switches the ATM. A transmitting / receiving unit 80 for transmitting to 50 and a monitoring unit 90 for monitoring the state of the transmitting / receiving signal of the transmitting / receiving unit 80 are configured.

The head-end unit 10 and the subscriber management unit (Subscriber Management System) 11 performs a linkage function with the subscriber management and billing system, and inputs the digital satellite broadcasting data to demultiplex the MPEG-2 TS for each channel An MPEG-2 encoder 13 for inputting an IRP 12, video data of various formats such as NTSC composite video signal, digital D1, RGB, CVBS, S-VHS and the like into MPEG-2 TS; The subscriber management unit 11, the IRP 12, and the MPEG-2 video decoder 13 are composed of an ATM mux (MUX) 14 for multiplexing the head-end video data.

The transmitting / receiving unit 80 demultiplexes the ATM data switched from the ATM switch 50 to the ATM for each channel, and multiplexes the ATM mux / demux 81 to multiplex the ATM data input from the rear end, and the ATM mux CDMA processing unit 82 for performing W-CDMA baseband processing on ATM data demultiplexed at / demux 81 and ATM data output from a separation unit to be described later, and ATM data baseband processing at CDMA processing unit 82. A combination unit (83) for combining the data, a modulator (84) for modulating Quadrature Amplitude Modulation (QM), and the data modulated by the modulator (84). UPCA / HPA (UP Converter Assembly / High Power Amplifier) 85, which amplifies the power to convert the RF signal to the 28 GHz band and transmits it to the cell site, and converts the ATM data of subscribers transmitted from the cell site to the IF signal. Low noise amplification DNCA / LNA [(DowN Converter Assembly / A low noise amplifier (85), a demodulator 87 for demodulating quadrature phase shift keying (QPSK) from the ATM data output from the DNCA / LAN 86, and the ATM data demodulated by the demodulator 87. A splitter 88 which separates each channel and transmits it to the CDMA processor 82, and a controller 89 that controls the operation of each of the building blocks 81 to 88.

Meanwhile, the VOD server unit 20 is largely composed of a hardware part, an operating system (OS) part, and a software part, and the hardware part supports MPEG-2 compression and stores a large amount of data capable of storing a plurality of contents. It must be capable of supporting RAID-3 and ATM interfaces in order to process programs in real time.

The OS portion generally uses a UNIX OS, but selects an OS that is easy to interwork between STBs (Set Top Box) and easy to operate on CD or VTR.

The software portion is divided into a system management layer, a server layer, an access library layer, and a database layer.

The operation of the head-end system of the LMDS using the W-CDMA scheme according to the present invention configured as described above is as follows.

First, the IRP 12 of the head end unit 10 inputs digital satellite broadcasting data and converts it into MPEG-2 TS data, and the MPEG-2 encoder 13 converts NTSC composite video signals, digital D1, RGB, CVBS, When the video data of various formats such as S-VHS is input and converted into MPEG-2 TS data, respectively, and transmitted to the ATM mux 14, the ATM mux 14 multiplexes the head-end image data to switch the ATM. Will output

In addition, the ATM switch 50 is not only the head-end image data output through the ATM mux 14 of the head end unit 10, but also the image program data or transcoder / communication matching unit provided from the VOD server unit 20. Input telephone and communication data of the PSTN / PSDN output through the 30 or internet data transmitted through the Internet matching unit 40.

In this case, the transcoder / communication matching unit 30 is required to provide telephone and communication data services, thereby maximizing the use of a wireless channel through a transcoder.

The transcoder is basically designed to cover more than 70,000 subscribers, and converts 64Kbps PCM data into 8Kbps vocoder output such as LD-CELP.

At this time, the modem data is bypassed without going through the transcoder.

Subsequently, the ATM switch 50 is a head-end video data and a telephone output from the head-end unit 10, the VOD server unit 20, the transcoder / communication matching unit 30 and the Internet matching unit 40. And converts communication data, Internet data, and the like into ATM data and switches the same to the transmitter / receiver 80.

Subsequently, the transmitting / receiving unit 80 demultiplexes the ATM data output from the ATM switch 50 for each channel through the ATM mux / demux 81, and then W-CDMA basis through the CDMA processing unit 82. Band processing is performed to the combination unit 83 for output.

Then, the combiner 83 combines all of the baseband processed ATM data to output to the modulator 84, and then modulator 84 performs QAM modulation on the ATM data to output to UPCA / HPA 85. .

Accordingly, the UPCA / HPA 85 frequency-converts the input ATM data into an RF signal of 28 GHz, and amplifies and transmits the high-power amplification to the subscribers of each cell site, thereby providing the respective LMDS digital services.

In contrast, when the subscriber ATM data is transmitted from the cell site to the head-end system according to the present invention, the RF signal transmitted from the cell site through the DNCA / LNA 88 of the transmitting / receiving unit 80 is first converted into an IF signal. Down-convert the frequency and then amplify the low noise and output the demodulation unit 87.

Thereafter, the demodulator 87 demodulates the ATM data by QPSK demodulation and outputs it to the separation unit 88, and then the separation unit 88 separates ATM data for each channel and outputs the same to the CDMA processing unit 82.

Then, the CDMA processing unit 82 W-CDMA baseband processing and multiplexed through the ATM mux / demux 81 to transmit to the ATM switch 50, ATM data is transferred to the ATM switch 50 The switching operation of the transmission to the CATV station providing the LMDS digital service.

On the other hand, the operation maintenance unit 70 is responsible for the efficient maintenance, maintenance, management and operation of the communication system for the various equipment and subscriber station equipment of all cell sites within the LMDS service range.

As described above, wireless LMDS digital services such as two-way CATV, satellite broadcasting, VOD, Internet, telephone, and the like can be performed through a head-end system located in a CATV broadcasting station implemented by the present invention. .

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram of a head-end system of an LMDS using a wideband-CD-DMA method according to the present invention.

* Explanation of symbols for main parts of the drawings

10: head end unit 20: VOD server unit

30: transcoder / communication matching unit 40: internet matching unit

50: ATM Switch 60: Level 1 Gateway

70: operation maintenance department 80: transmission / reception unit

90: monitoring unit

Claims (1)

Subscriber management unit 11 which performs linkage function with subscriber management and billing system, IRP 12 which inputs digital satellite broadcasting data and demultiplexes into MPEG-2 TS for each channel, and inputs image data of various formats The MPEG-2 encoder 13 for converting the MPEG-2 TS into the MPEG-2 TS and the head-end video data output from the subscriber management unit 11, the IRP 12, and the MPEG-2 encoder 13. ), A head-end unit (10) configured with a VOD server unit (20) for providing video program data, and a transcoder / communication matching unit (30) for receiving telephone and communication data by matching with a PSTN / PSDN. Internet matching unit 40 for receiving Internet data in accordance with the Internet network, the head-end unit 10, VOD server unit 20, transcoder / communication matching unit 30 and the Internet matching unit ( Head-end video data, telephone and communication data, and internet data output from 40) An ATM switch 50 for converting and switching the data, a level 1 gateway 60 connected to the ATM switch 50 to provide a VOD menu and signaling process of the VOD server unit 20, and the ATM switch. An operation maintenance unit 70 connected to the network 50 and in charge of network management and operation maintenance, and ATM data switched from the ATM switch 50 to the ATM, demultiplexed for each channel, and inputted at a later stage. ATM mux / demux 81 for multiplexing the CDMA processor 82 for baseband processing W-CDMA ATM data demultiplexed by the ATM mux / demux 81 and ATM data output from a separation unit to be described later. ), A combiner 83 that combines the baseband processed ATM data by the CDMA processor 82, a modulator 84 that QAM modulates the combined ATM data by the combiner 83, and the modulation. RF signal of 28 GHz band UPCA / HPA 85 for converting and amplifying power to be transmitted to the cell site, DNCA / LNA 86 for converting ATM data of subscribers transmitted from the cell site into an IF signal and low noise amplifying the DNCA / LNA ( A demodulation unit 87 for QPSK demodulation of the ATM data output from the processor 85; a separation unit 8S for separating the ATM data demodulated by the demodulation unit 87 for each channel and transmitting the same to the CDMA processing unit 82; Transmitter / receiver 80 composed of control unit 89 for controlling the operations of the respective component blocks 81 to 88, and monitoring unit 90 for monitoring the state of the transmit / receive signal of the transmit / receive unit 80. Head-end system of the LMS (LMDS) using a broadband-CDDMA method, characterized in that consisting of.

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