KR100370055B1 - HUB outdoor unit in LMDS system - Google Patents

Abstract

The present invention relates to a Local Multipoint Distribution Service (hereinafter referred to as LMDS) system, and more particularly, a reception block for amplifying and frequency-converting upstream signals for each sector received from a radio section in an LMDS system. It relates to a hub outdoor unit (HOU) that shares a Micro Wave Converter.

To this end, in an LMDS system that manages subscribers by dividing one cell into four sectors, a hub outdoor device in which upstream signals of different frequency bands are combined into one stream signal for each sector is amplified and down-frequency processed. Outdoor Unit).

Description

HUB outdoor unit in LMDS system

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LMDS system. In particular, a hub outdoor unit (HOU) sharing a reception block (Micro Wave Converter) for amplifying and frequency converting upstream signals for each sector received from a wireless section in an LMDS system. ).

In general, due to the development of wireless communication technology and the development of the millimeter wave band, a broadband wireless subscriber network (B-WLL), which is advantageous in terms of ease of network construction, scalability, and economics, is in the spotlight.

In order to realize the broadband wireless subscriber network (B-WLL), Korea announced the frequency in the 20 GHz band, and similar systems include the Canada's Local Multipoint Communication System (LMCS) and the US Regional Multipoint. Distributed Services (LMDS) and ATM Wireless Access (AWA) in Japan are being studied.

Standardization in relation to broadband wireless subscriber networks (B-WLL) is most prominent in the work of the Digital Audio Visual Council (abbreviated as DAVIC).

DAVIC publishes the 1.0 specification up to the 1.3 specification and presents the only specific standard for the broadband wireless subscriber network (B-WLL). DAVIC mentions down time division multiplexing (TDM), up time division multiple access (TDMA) multiple access schemes, and downlink, uplink frame structure, and media access control protocol. have.

In Korea, Ministry of Information and Communication Announcement No. 1997-49 specifies the frequency for the subscriber line of the broadband wireless subscriber network (B-WLL), which allocates 2 하향 down from 25.5 ㎓ to 27.5 에서 for bidirectional broadband service in the 20 ㎓ band. Upwardly, 500 MHz of 24.25 Hz to 24.75 Hz was allocated. Of these, the 800 MHz band of 26.7 GHz to 27.5 GHz was temporarily designated for cable television (CATV) transmission.

As such, ultra-high-speed broadband multimedia service using subscriber line frequency in the millimeter wave band (2MHz downwards 25.5㎓-27.5㎓ and 500MHz upwards 24.25㎓24.75㎓) for subscribers within a radius of about 2-5km. An LMDS system that provides is a system developed to deliver multi-channel TV programs to subscribers as a competition for wirelines in the cable television market.

Initially mainly used for cable TV distribution, it gradually developed into a two-way digital system, and the services that a system of two-way high-speed wireless communication concept can provide include voice telephone service, data communication service, interactive video service, voice / data / There are multimedia services and dedicated line services that combine video, and have subscriber types such as general public network subscribers, private network subscribers, and public network transmission relays.

In addition, LMDS is a broadband wireless subscriber network that provides wireless cable television service or high-speed Internet service using subscriber line frequencies in the millimeter wave band (2.535 GHz to 2.655 GHz) for subscribers within a radius of about 30 to 50 km. Standards are also presented in the DAVIC 1.3 specification.

1 is a block diagram showing a general LMDS system configuration.

Referring to FIG. 1, the LMDS system may be broadly classified into a service provider 100 and a customer premises equipment unit (CPE) 200.

Among these, the service provider 100 may include a central office unit (COU) 110, a head-end unit 120, and a hub outdoor unit (HOU) 130. Can be classified as

The central office device (COU) 110 may appropriately multiplex the program and service contents supplied from each program provider, that is, the digital data stream through the network access device 111, thereby providing a headend device ( Head-end unit) 120.

In addition, the central office unit (COU) 110 is provided with a network management unit 117 responsible for network management of the entire system, the integrated network management control station 116, and the billing processing unit 115 in charge of the subscriber billing; have.

The head-end unit 120 modulates a downstream signal of the ATM cell structure transmitted from the network connection device 111 and transmits the downstream signal to the hub outdoor device 130 and the hub outdoor device. The demodulated upstream signal transmitted from 130 is transmitted to the network access device 111.

The hub outdoor device 130 amplifies and frequency-converts the downstream signal transmitted from the head-end unit 120 and transmits the signal to the subscriber through a high-directional antenna, and receives an uplink received through a wireless section. Amplified and frequency-converted stream signals are delivered to the head-end unit (120).

The service provider 100 and the CPE 200 described above have a millimeter wave band (2 MHz of 25.5 kHz to 27.5 GHz and 500 MHz of 24.25 kHz to 24.75 GHz). Send and receive downstream and upstream signals.

Figure 2 is a block diagram showing the configuration of the hub outdoor device of a typical LMDS system.

The hub outdoor device is largely divided into a transmitter and a receiver.

The transmitting end is a band pass filter (BPF) 300 that is modulated by a head-end unit and passes only a desired signal from a single output downstream signal, and a downward pass through the band pass filter (BPF) 300. A 4-way divider 310 and a 4-way divider 310 which equally distribute the stream signal and deliver the stream signal to each transmission block (MWC) 320, 330, 340 and 350 related to transmission in each sector of the divided cells. A plurality of transmission blocks (MWC1, MWC2, MWC3, MWC4) (320, 330, 340, 350) for frequency-converting and amplifying each downstream signal transmitted from the microwave band and the amplified downstream signals of each of the transmission blocks (320, 330, 340, 350) are wireless sections. Antenna unit 360, 370, 380, and 390 to be transmitted. Herein, the antenna units 360, 370, 380, and 390 each of the plurality of transmit antennas ANT1, ANT2, ANT3, ANT4, 363, 373, 383, 393 and the transmit antennas 363, 373, 383, 393 or the cable (cable) that emit downstream signals amplified by the transmission blocks 320, 330, 340, and 350, respectively. As described above, a plurality of isolators 361 for protecting the transmission blocks 320, 330, 340, and 350, and each transmission block 320, 330, 340, 350 operate normally when radiating the amplified downstream signals through the respective transmission antennas 363, 373, 383, 393. It consists of a bi-directional coupler 362 that detects a portion of the downstream signal that is radiated to see if it is.

In particular, each transmission block (320, 330, 340, 350) is a local signal generator 321 for generating a local signal for frequency conversion of the downstream signal to a microwave band, and the frequency for mixing the divided local input downstream signal with the generated local signal Mixer 322, a drive amplifier 323 for first amplifying the downstream signal frequency-converted into a microwave band signal, and a bandpass for removing noise components from the first amplified downstream signal A filter (BPF) 324, a main amplifier 325 for second-order amplifying the pure downstream signal from which the noise components have been removed, and a low pass for removing noise components from the second amplified downstream signal. A pass filter (LPF) 326.

The receiver amplifies and intermediates multiple reception antennas (ant1, ant2, ant3, and ant4) 400, 401, 402 and 403 for receiving an upstream signal from each predetermined sector through a radio section, and upstream signals received through each of the reception antennas 400, 401, 402 and 403. Noise in each of the multiple reception blocks (mwc1, mwc2, mwc3, mwc4) (410, 420, 430, 440) for frequency conversion in the frequency band (400 MHz to 700 MHz) and each upstream signal frequency-converted in each reception block (410, 420, 430, 440) into the intermediate frequency band. 4, which combines multiple intermediate frequency blocks 450, 460, 470 and 480 for removing and amplifying components, and four upstream signals for each sector passing through each intermediate frequency block 450, 460, 470 and 480, to be delivered to a head-end unit. 4 way combiner 490.

Here, each of the reception blocks 410, 420, 430, and 440 is a low noise amplification of a band pass filter (BPF) 411 for removing noise components from upstream signals received through each of the reception antennas 400, 401, 402, and 403, and an upstream signal from which the noise components have been removed. A low noise amplifier (LNA) 412, a local signal generator 413 for generating a local signal for frequency converting the amplified upstream signal to an intermediate frequency band, and amplified upstream signal with the generated local signal It consists of a frequency mixer 414.

In addition, each intermediate frequency block 450, 460, 470, 480 includes a low pass filter (LPF) 451 that removes noise components from an upstream signal frequency-converted into an intermediate frequency band in each receiving block (410, 420, 430, 440), and a pure intermediate from which the noise components are removed. It consists of an intermediate frequency amplifier 452 for amplifying an upstream signal of frequency.

In the conventional LMDS system configured as described above, one cell is divided into four sectors to manage subscribers. To this end, each receiving block of a hub outdoor unit is provided with a number of sectors.

However, the LMDS system uses subscribers in the millimeter-wave band (2 kHz down 25.5 kHz to 27.5 GHz, 500 MHz upward 24.25 kHz to 24.75 kHz) for subscribers within a radius of about 2 to 5 km. If a device such as a low noise amplifier (LNA) or a frequency mixer is used in the receiving block by the number of sectors, there is a problem in that the cost of implementing the system is high.

An object of the present invention is to solve the above problems, in the LMDS system that manages subscribers by dividing one cell into four sectors, upstream signals of different frequency bands into one stream signal for each sector. Provided is a Hub Outdoor Unit that is combined to amplify and downlink.

Hub outdoor device of the LMDS system according to the present invention for achieving the above object, in the LMDS system consisting of a service provider and a plurality of sector-specific subscriber device, each sector of a different frequency band from the subscriber device for each sector A plurality of receiving antennas for receiving a stream signal, a combiner for combining the received stream signals for each sector into a single output, amplifying the combined single stream signal, and receiving a downlink frequency of the amplified signal A block, a divider for separating the frequency down-processed single stream signal, and a plurality of intermediate frequency blocks for filtering and amplifying only the sector-specific stream signal from the separated stream signal.

Preferably, each intermediate frequency block is provided with a band pass filter for filtering only the stream signal of the intermediate frequency for each sector from the stream signal separated by the divider.

1 is a block diagram showing a general LMDS system configuration.

Figure 2 is a block diagram showing the configuration of the hub outdoor device of a typical LMDS system.

Figure 3 is a block diagram showing the configuration of the hub outdoor device of the LMDS system according to the present invention.

4 illustrates a cell layout of a typical LMDS system.

* Description of the symbols for the main parts of the drawings *

610: first combiner 620: reception block (mwc1, mwc2, mwc3, mwc4)

630: divider (4way divider)

Hereinafter, a preferred embodiment of a hub outdoor device of an LMDS system according to the present invention will be described with reference to the accompanying drawings.

Figure 3 is a block diagram showing the configuration of the hub outdoor device of the LMDS system according to the present invention.

Referring to Fig. 3, the hub outdoor device of the present invention is also largely divided into a transmitting end and a receiving end.

As in the prior art, a band pass filter (BPF) 500 and a band pass filter (BPF) 500 that pass only desired signals of a single output downstream signal modulated by a head-end unit as in the related art. 4-way divider (510) and 4-way for equally distributing the downstream signal passing through and passing it to each transmission block (MWC) (520, 530, 540, 550) related to the transmission of each sector of the divided cells A plurality of transmission blocks (MWC1, MWC2, MWC3, MWC4) 520, 530, 540, 550 for frequency converting and amplifying each downstream signal transmitted from the divider 510 into the microwave band, and downstream amplified in each transmission block 520, 530, 540, 550, respectively. The antenna unit 560, 570, 580, 590 for transmitting a signal to the radio section. Herein, the antenna units 560, 570, 580, 590 may include a plurality of transmit antennas ANT1, ANT2, ANT3, ANT4, 563, 573, 583, 533, and transmit antennas 563, 573, 583, 533, or a cable that can emit downstream signals amplified by the transmission blocks 520, 530, 540, 550, respectively. As described above, a plurality of isolators 561 for protecting the transmission blocks 520, 530, 540, 550, and each transmission block 520, 530, 540, 550 normally operate when radiating the amplified downstream signals through the respective transmission antennas 563, 573, 583, 593. It consists of a bi-directional coupler 562 which detects a portion of the downstream signal being emitted to determine if it is.

In particular, each transmission block 520, 530, 540, 550 includes a local signal generator 521 for generating a local signal for frequency converting the downstream signal into a microwave band, and a frequency for mixing the divided downstream input signal with the generated local signal. Mixer 522, a drive amplifier 523 for first amplifying the downstream signal frequency-converted into a microwave band signal, and a bandpass for removing noise components from the first amplified downstream signal A filter (BPF) 524, a main amplifier 525 for second-order amplifying the pure downstream signal from which the noise components have been removed, and a low pass for removing noise components from the second amplified downstream signal. And a pass filter (LPF) 526.

The configuration of the transmitter is the same as in the prior art, and the configuration of the receiver is unique in the present invention.

In the present invention, the receiving end of the hub outdoor device (HOU) is a plurality of receiving antennas (ant1, ant2, ant3, ant4) (600, 601, 602, 603) for receiving upstream signals of different frequencies from each predetermined sector through a wireless section, respectively. Amplifying a first combiner (4way combiner1) 610 for combining the upstream signal received through the receiving antenna (600,601, 602, 603) into one stream signal, and the upstream signal combined in the first combiner (610) And a divider for separating the reception block (mwc) 620 for frequency conversion into the intermediate frequency band (400 MHz to 700 MHz) and the upstream signal frequency converted in the reception block 620 into the intermediate frequency band into signals for each sector. (4way divider) 630, a plurality of intermediate frequency blocks 640, 650, 660, 670 for removing and amplifying noise components in separate upstream signals for each sector, and four sectors for each sector passing through each intermediate frequency block 640, 650, 660, 670, respectively. Combining the aroma stream signal to one consists of a second combiner (4way combiner2) (680) to pass to the head end device (Head-end Unit).

Here, the reception block 620 is a band pass filter (BPF) 621 that removes noise components from the upstream signals received through each of the receiving antennas 600, 601, 602, and 603, and low noise amplifies the upstream signals from which the noise components are removed. A low noise amplifier (LNA) 622, a local signal generator 623 for generating a local signal for frequency converting the amplified upstream signal to an intermediate frequency band, and a mixed upstream signal with the generated local signal Frequency mixer 624.

In addition, each intermediate frequency block (640, 650, 660, 670) is a band pass filter (BPF) 641 that removes the noise component from the upstream signal frequency-converted to the intermediate frequency band in the receiving block 620 and passes only the stream signal of the corresponding sector; It consists of an intermediate frequency amplifier 642 for amplifying upstream signals for each sector of pure intermediate frequency from which noise components are removed.

The LMDS system according to the present invention configured as described above manages subscribers by dividing one cell into four sectors.

4 is a diagram illustrating a cell arrangement of a general LMDS system.

As shown in Fig. 4, each cell is composed of four sectors.

In the LMDS system of the present invention, the service provider and the subscriber unit (CPE) are provided with a downlink of a millimeter wave band (2 GHz of 25.5 GHz to 27.5 GHz and 500 MHz of 24.25 GHz to 24.75 GHz). An upstream signal is exchanged, and a subscriber station (CPE) of each sector transmits an upstream signal of a microwave band determined for each sector.

For example, the frequency used in each sector of the first cell C1 is 24.250 kHz to 24.252 kHz in the first sector Sector1, 24.350 kHz to 24.352 kHz in the second sector Sector2, and in the third sector Sector3. 24.450 Hz to 24.452 Hz and 24.548 Hz to 24.550 Hz in the fourth sector, each of the high-directional antennas of the Hub Outdoor Unit according to the present invention is the first antenna (ant1) 600. 24.250 ㎓ to 24.252, 24.350 ㎓ to 24.352 에서 at the second antenna (ant2) 601, 24.450 ㎓ to 24.452 에서 at the third antenna (ant3) 602, 24.548 4 at the fourth antenna (ant4) 603 Receive each upstream signal from V to 24.550 mV.

Here, a number of high-directional antennas used in the LMDS system transmit downstream signals, which are frequency-converted and amplified in the transmission blocks (MWC) (520, 530, 540, 550), to sectors belonging to their directivity angles, and at the same time the high of the reception block (mwc) 620. The directional antenna receives a subscriber signal, that is, an upstream signal, from a sector belonging to its directing direction. This highly directional antenna is operated to have a direct angle in the direction of each sector specified at the time of initial installation of the system.

Thereafter, the first combiner (4 way combiner) 610 combines the upstream signals for each sector received through each of the receiving antennas 600, 601, 602, and 603 to " 24.250 ㎓ to 24.252 ㎓ + 24.350 ㎓ to 24.352 ㎓ + 24.450 ㎓ to 24.452 결합. An upstream signal of frequency ㎓ + 24.548 kHz to 24.550 GHz "is delivered to the receiving block 620.

The receiving block 620 amplifies the upstream signal combined in the first combiner 610 and frequency-converts the intermediate frequency band to " 400 MHz to 402 MHz + 500 MHz to 502 MHz + 600 MHz to 602 MHz + 698. Outputs an upstream signal of intermediate frequency from MHz to 700 MHz. At this time, the local signal generator 623 generates a local signal of 23.850 kHz to produce the upstream signal of the intermediate frequency band.

The upstream signal frequency-converted into the intermediate frequency band is separated by a divider (4way divider) 630 and then transmitted to a plurality of intermediate frequency blocks 640, 650, 660 and 670 that remove and amplify noise components from the upstream signal for each sector.

Then, in each intermediate frequency block (640, 650, 660, 670) using a band pass filter (BPF) 641 to remove the signal components acting as noise in the upstream signal frequency-converted to the intermediate frequency band in the receiving block 620, and then for each sector Only the upstream signal is passed, and the operation is the same as before.

As a result, in each intermediate frequency block 640, 650, 660 and 670, "400 MHz to 402 MHz" in the first intermediate frequency block 640, "500 MHz to 502 MHz" in the second intermediate frequency block 650, and the third intermediate frequency block 660. ) Amplifies and outputs an upstream signal of " 600 MHz to 602 MHz " and the fourth intermediate frequency block 670 of " 698 MHz to 700 MHz "

As described above, in the present invention, a reception block for downlinking an upstream signal for each sector into an intermediate frequency band is shared. In other words, the upstream signals of each sector are combined into a stream signal of an intermediate frequency band. As a result, only a number of cells are required for a receiving block including a device such as a low noise amplifier (LNA) or a frequency mixer, which is quite expensive.

As a result, the cost of implementing the entire LMDS system is significantly reduced. It also maximizes the advantages of the LMDS system in terms of installation and maintenance costs compared to wired multimedia communication systems.

Claims (2)

In an LMDS system consisting of a service provider and a plurality of sectoral subscriber devices, A plurality of reception antennas for receiving each stream signal of a different frequency band from the subscriber device for each sector; A combiner for combining the received stream signals for each sector and outputting a single signal; A receiving block for amplifying the combined single stream signal and down-processing the frequency of the amplified signal; A divider for separating the frequency down-processed single stream signal; And a plurality of intermediate frequency blocks for filtering and amplifying only the stream signals of the corresponding sectors from the separated stream signals. The method of claim 1, wherein each intermediate frequency block, And a band pass filter for filtering only a stream signal of an intermediate frequency for each sector from the stream signal separated by the divider.