KR19990004465A - Signal redundancy device at cell site of LMS - Google Patents

Abstract

In the LMDS using a wideband-CDMA (W-CDMA) scheme, the present invention serves as a signal relay for transmitting an LMDS service signal from an LMDS broadcasting station to each subscriber and a service request signal received from each subscriber to the LMDS broadcasting station. The present invention relates to a signal repeater at a cell site end of an LMDS, which converts a 27.5-29.5 GHz microwave signal of vertical polarization containing an LMDS digital service signal received from an LMDS station into an 950-2050 MHz IF signal. Next, the converted IF signal is rearranged, amplified above a specific signal level, and then converted into a microwave signal of 27.5-29.5 GHz of horizontal polarization, which is transmitted to the subscriber end, followed by a 27.5 LMDS digital service request signal received from the subscriber end. Convert microwave signals from ~ 29.5 GHz to IF signals from 200 to 400 MHz and reamplify above a certain signal level A microwave signal of 27.5 ~ 29.5GHz to be sent to the head and stage for LMDS station.

Description

Signal redundancy device at cell site of LMS

The present invention relates to an LMDS broadcasting station in a Local Multipoint Distribution System (hereinafter referred to as an "LMDS") using a wideband-code division multiple access (CDMA) scheme. Receives an LMDS service signal to each subscriber and transmits the service request signal received from each subscriber to the LMDS broadcasting station. It is about.

Recently, LMDS has adopted a wireless access communication method using W-CDMA to perform various LMDS digital services such as interactive CATV and video on demand (VOD).

Meanwhile, in order for the LMDS to perform digital LMDS services in a nationwide and extensive region in the 28 GHz band, it is necessary to design a network in which each region is composed of LMDS cell units in a range of frequency, that is, a radius of 5 km.

At this time, each cell seat stage of which the network configuration is a basic unit is located between the LMDS broadcasting station providing the LMDS service and the subscriber receiving the service, and thus needs to transmit / receive a link signal. The signal retransmission device at the cell site stage for performing the above is not implemented.

Accordingly, the present invention has been made in view of the above, and an object thereof is to receive an LMDS service signal from an LMDS station and transmit it to each subscriber, and to transmit a service request signal received from each subscriber to the LMDS station. An object of the present invention is to provide a signal repeater at a cell site of an LMDS capable of performing a relay role.

In order to achieve the above object, the signal retransmission device of the cell site stage of the LMDS of the present invention is a microwave signal of 27.5-29.5 GHz in a water-wave polarization containing an LMDS digital service signal received from an LMDS broadcasting station as an IF signal of 950-2050 MHz. Down-convert, then rearrange the converted IF signal and amplify it above a specific signal level, convert it into 27.5 ~ 29.5GHz microwave signal of horizontal polarization, and transmit it to the subscriber end, and receive the LMDS digital service request signal received from the subscriber end. It converts the 27.5 ~ 29.5GHz microwave signal contained in the signal into a 200 ~ 400MHz IF signal and re-amplified above a specific signal level and transmits the 27.5 ~ 29.5GHz microwave signal to the head end of the LMDS broadcasting station.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram of an apparatus for re-signaling a signal at a cell site end of an LMDS using a wideband-to-DMA system according to the present invention.

Explanation of symbols for main parts of the drawings

1: Head and End 2: 1st LNA

3: first down converter 4: separator

5: Up / Down IF signal processing unit 6: First up converter

7: first HPA 8: subscriber

9: second LNA 10: second down converter

11 synthesis unit 12 second up converter

13: second HPA 14: stool / demodulation

15: CDMA processor 16: ATM processor

17 control and monitoring unit 18 power supply unit

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration and operation of the signal relay device at the cell site end of the LMDS of the present invention.

1 is a block diagram of a signal repeater at the cell site end of an LMDS according to the present invention, and receives a 27.5-29.5 GHz microwave signal of vertical polarization from a headend 1 of an LMDS station. A first low noise amplifier (hereinafter referred to as "LNA") (2) for removing noise and a 27.5-29.5 GHz microwave signal passing through the first LNA 2 at an interval of 950 to 2050 MHz. Separating the first down converter 3 down-converting to an intermediate frequency signal (hereinafter referred to as 'IF') and the IF signal down by the first down converter 3 by a predetermined power. A splitter 4, an up / down IF new signal processor 5 for rearranging an IF signal input through the splitter 4, or processing an IF signal input from a subscriber; The IF signal processed by the downlink IF signal processor 5 is upgraded to a microwave signal of 27.5-29.5 GHz. A first up-converter 6 for converting and a microwave signal of 27.5-29.5 GHz up by the first up-converter 6 are amplified by a predetermined power to convert a microwave signal of 27.5-29.5 GHz of horizontal polarization. A first high power amplifier (hereinafter referred to as 'HPA') 7 transmitted to the subscriber station 8 and a microwave signal of 27.5 to 29.5 GHz are received from the subscriber station 8 to remove noise. A second down converter 10 for down converting a microwave signal of 27.5-29.5 GHz passing through the second LNA 9 into an IF signal of 200-400 MHz, and the second down; A combiner 11 for synthesizing the IF signal output from the up / down IF signal processor 5 which processes the IF signal down by the converter 10, and is output through the combiner 11. A second up converter 12 for up-converting an IF signal into a microwave signal of 27.5-29.5 GHz, and the second up converter 12 A second HPA 13 which amplifies a microwave signal of 27.5-29.5 GHz up to a predetermined power and transmits it to the head-end terminal 1 of the LMDS broadcasting station; and an IF signal output through the separating unit 4 A modulator / demodulator 14 for demodulating and outputting a modulated or CDMA-processed signal to the combiner 11 and a CDMA process for a modulated signal or an ATM processed signal inputted through the modulator / demodulator 14. ATM processing unit 16 for ATM processing a CDMA processing unit 15, a signal processed through the CDMA processing unit 15 or a detection signal according to an operation state of a cell site, and an ATM processed through the ATM processing unit 16; It consists of a control and monitoring unit 17 for controlling various parameters related to up / down transmission / reception of link signals through the signal, monitoring the operation and status of the cell site, and a power supply unit 18 for performing an uninterruptible power supply function. do.

The signal repeater of the cell site end of the LMDS of the present invention configured as described above is a device for re-relaying the microwave signal of the band 27.5 ~ 29.5GHz transmitted from the head end stage 1 or the Gaiza stage 8, The transmission / reception method of the signal between the end 1 and the cell site end adopts a point-to-point link method, and employs an omni antenna between the cell site end and each subscriber to adopt a one-to-many communication method.

In LMDS stations, link signals to cell sites may be used wirelessly, or wired cables such as optical cables may be used.

Meanwhile, the present invention implements a signal repetition apparatus using wireless. In this case, when the wireless is used, since the same frequency band is used as the signal transmitted from the subscriber to the cell site, it is characteristic of the giga (GHz) band frequency. Use vertical polarization and horizontal polarization respectively to avoid interference with each other.

In addition, the present invention implements the W-CDMA scheme in a multiple access scheme, and reprocesses and transmits the W-CDMA RF signal only at the IF signal level.

Referring to the operation of the signal repeater at the cell site end of the LMDS of the present invention configured as described above, first, the first LNA 2 is 27.5-29.5 GHz of vertical polarization received from the head-end end 1 of the LMDS broadcasting station. Removes noise from the microwave signal.

At this time, the microwave signal of 27.5 ~ 29.5GHz will carry a signal for providing various LMDS digital services requested by each subscriber.

The first down converter 3 down-converts the microwave signal of 27.5-29.5 GHz from which the noise is removed to an IF signal of 950-2050 MHz.

Subsequently, the down-converted IF signal is separated by a predetermined power by the separating unit 4 and then input to the up / down IF signal processing unit 5 to be rearranged.

Then, the IF signal processed by the up / down IF signal processing unit 5 as described above is up-converted into a microwave signal of 27.5-29.5 GHz, which is a horizontal polarization, through the first up converter 6, and then Power is amplified in the HPA 7 and transmitted to each subscriber station 8.

Then, each subscriber station 8 can receive the LMDS digital service requested by the subscriber.

On the other hand, when each subscriber station 8 transmits the LMDS digital service request signal to the LMDS broadcasting station, the second LNA 9 receives a 27.5-29.5 GHz microwave signal carrying the service request signal to remove noise.

Subsequently, when the second down converter 10 down-converts the noise-free 27.5-29.5 GHz microwave signal into an 200-400 MHz IF signal and outputs it to the up / down IF signal processor 5, the up / down IF signal is output. The signal processor 5 converts the down-converted IF signal of 200 to 400 MHz into an IF signal having an appropriate size, and outputs the converted IF signal to the combiner 11.

As described above, the IF signal output to the combining unit 11 is synthesized and up-converted into a microwave signal of 27.5 to 29.5 GHz through the second up converter 12, and then the power is amplified in the second HPA 13 to LMDS. It is transmitted to the head end of the broadcasting station 1.

Then, according to the service request signal input through the head-end stage 1, the LMDS broadcasting station provides the corresponding LMDS digital service.

Meanwhile, the modulator / demodulator 14, the CDMA processor 15, and the ATM processor 16 set up a separate communication channel for remote control, operation, and collection of an alarm signal at a cell site, and operate in an LMDS broadcasting station. Perform communication with the maintenance system.

The control and monitoring unit 17 controls, sets, and monitors / operates various parameters related to up / down transmission / reception of the cell site through data transmission / reception with the ATM processing unit 16. .

In addition, it can be connected to the control program adopting the GUI method so that dispatch personnel can operate as needed, and the control of the transmission / reception system is remotely performed and monitored remotely by the operation maintenance system of the LMDS broadcasting station.

As described above, the present invention implements a signal relay at each cell site end of the LMDS to transmit / receive a link signal between the LMDS station and the subscriber, thereby efficiently providing the LMDS digital service supported by each subscriber from the LMDS station. There is an effect that can be provided as.

Claims (2)

A first LNA (2) for receiving a vertically polarized microwave signal from the head-end terminal (1) of the LMDS broadcasting station to remove noise, and a second signal for down-converting the microwave signal passing through the first LNA (2) to an IF signal; Reorders the first down converter 3, the separator 4 separating the IF signal down by the first down converter 3 by a predetermined power, and the IF signal input through the separator 4. An up / down IF signal processor 5 for processing an IF signal or a signal input from a subscriber, and a first up converter 6 for up-converting the IF signal processed by the up / down IF signal processor 5 into a microwave signal; And a first HPA 7 which amplifies the microwave signal up by the first up converter 6 by a predetermined power and transmits a horizontally polarized micro signal to the subscriber end 8, and the subscriber end 8. Receive a microwave signal from the 2 LNA (9), the second down converter 10 for down converting the microwave signal passing through the second LNA (9) to an IF signal, and the IF signal down by the second down converter 10 A synthesis unit 11 for synthesizing the IF signal output from the up / down IF signal processing unit 5 for processing, and a second up converter for up-converting the IF signal output through the synthesis unit 11 into a microwave signal ( 12) and a second HPA 13 which amplifies the microwave signal up by the second up-converter 12 by a predetermined power and transmits it to the head-end terminal 1 of the LMDS broadcasting station. Signal repeater at cell site end of LMDS. The modulator / demodulator 14 of claim 1, wherein the modulator / demodulator 14 modulates an IF signal input through the separator 4 or demodulates a CDMA-processed signal and outputs the demodulated signal to the combiner 11; ATM processing of the CDMA processing unit 15 for performing CDMA processing on the modulation signal or ATM processed signal inputted through the grandfather 14 and the monitoring signal according to the operation state of the signal or cell site processed by the CDMA processing unit 15. Control and monitoring to control various parameters related to up / down transmission / reception of the link signal and to monitor the operation and status of the cell site through the ATM processing unit 16 and the ATM signal processed by the ATM processing unit 16 And a unit (17), and a power unit (18) for performing an uninterruptible power supply function.