KR100277337B1 - CDMA mobile telecommunication service providing method for solving RF null area and frequency converter therefor - Google Patents

Abstract

The present invention relates to a CDMA mobile communication service providing method and a frequency conversion apparatus therefor for eliminating the shadow area, the service providing method is not installed in the base station is installed, the base station is out of the service area (service area) A method of providing a CDMA mobile communication service to an area (shading area) to provide a service, comprising: a forward link step of transmitting information from a service area to a shadow area; And a reverse link step of transmitting information from the shadow area to the service area. The forward link step includes transmitting information to be transmitted by a base station in a service area using a first transmission frequency in a predetermined CDMA mobile communication service band; Receiving a first transmission frequency in a service area, converting the radio frequency into a second transmission frequency in a CDMA mobile communication service band, and wirelessly transmitting it; Receiving a second transmission frequency signal in a shaded area and converting the signal to a first transmission frequency; And providing a CDMA mobile communication service to a subscriber in the shadow area by using the converted first transmission frequency signal.

According to the present invention, it is possible to provide a mobile communication service to the subscriber station of the shadow area at low cost. In addition, it is possible to efficiently detect the failure of the DU of the outdoor frequency converter.

Description

CDMA mobile telecommunication service providing method for solving shadow area and frequency converter therefor {CDMA mobile telecommunication service providing method for solving RF null area and frequency converter therefor}

The present invention relates to a frequency converter for a mobile communication service, and more particularly, to a method for providing a CDMA mobile communication service in an RF null area and an outdoor type frequency converter for the same.

In terms of the traffic traffic of CDMA mobile communication, 85% of the communication traffic is concentrated in 5% of the total area of the mobile communication service, and only 15% of traffic is generated in the remaining 95% of the area. . Therefore, it is more efficient to use repeaters instead of base stations, which are expensive to install and maintain, in order to extend the coverage of digital mobile phones at low cost to major areas such as highways, national roads and open areas where traffic is low but coverage is important. Conventional repeaters, however, are commonly used to cover RF null areas created by buildings, forests, tunnels, underground spaces or certain obstacles. That is, it is mainly used in indoor spaces such as underground spaces or large buildings where ground and underground are clearly separated. 1 illustrates a conventional repeater used in an area open from a ground relay or a radio wave, that is, a highway, a national road, and an open area. As shown in FIG. 1, when the existing repeater is installed outdoors, the frequencies of F1 (1840-1850 MHz) and F2 (1750-1760 MHz) are equally used for the link antenna (A) and the coverage antenna (B) of the repeater. do. In this case, there are many restrictions on the use due to the feedback phenomenon of the signal amplified by the repeater, that is, the spill over phenomenon.

In order to solve such a phenomenon, the signal received from the base station at the input terminal A of the repeater should be 15 dB or more larger than the signal from which the loopback signal is output from the coverage antenna B. If the gain of the repeater is 80dB and the gain of the link antenna is 15dB, the isolation of the receiver of the repeater link antenna A and the coverage antenna B should be 80 + 15 + 15 = 110dB or more.

This condition is very difficult in the outdoor environment, so in order to overcome this, a ground relay method using fiber optics or trunk cables is used as shown in FIG. 2, but it is extremely limited due to limitations in installation and coding. It is true. In the case of terrestrial relay method using T1 / E1 link, mobile phone system can be limitedly applied to analog system such as AMPS or digital system using TDMA method. However, in case of CDMA, application is almost impossible due to bandwidth limitation. Do. In case of using Fiber Optic Cable, it can be applied to all methods such as AMPS, TDMA, CDMA, but it is necessary to install optical cable between base station and repeater respectively. In other words, the optical cable should be produced and installed in consideration of the wavelength of the optic cable according to the frequency. Telecommunications providers are avoiding adoption. Therefore, there is a need for a relay application device using a wireless link that can replace the wire link described above.

SUMMARY OF THE INVENTION The present invention has been made in an effort to solve the above problems, and provides a CDMA mobile communication service for solving a shadow area for providing a mobile communication service to a CDMA mobile communication subscriber station in a shadow area. To provide.

Another technical problem to be achieved by the present invention is to provide an outdoor type frequency conversion apparatus that can be installed in open areas and highways for providing CDMA mobile communication services in the shaded area.

Another object of the present invention is to provide a DU failure detection method for maintenance of an outdoor type frequency converter.

1 illustrates a conventional repeater used in an area open from a ground relay or a radio wave, that is, a highway, a national road, and an open area.

Figure 2 shows the ground relay method using a fiber optic or trunk cable to eliminate the shadow area.

3 schematically illustrates a CDMA mobile communication network configuration based on a repeater.

4 illustrates a channel arrangement of a domestic personal mobile communication (PCS) provider.

<Explanation of symbols for the main parts of the drawings>

300: service area, 310: base station

320: DU of outdoor frequency inverter

322: Solar Cells and Batteries

330: Outdoor frequency inverter

340: RU of outdoor frequency inverter, 350: shaded area

360: subscriber terminal in the shaded area, 370: surveillance center

According to the present invention for solving the above technical problem, the method for providing a CDMA mobile communication service for resolving the shadow area is to provide a service that does not have a base station, which is out of the area (service area) where the base station is installed and serviced. A method of providing a CDMA mobile communication service to an area (shading area), the method comprising: a forward link step of transmitting information from the service area to a shadow area; And a reverse link step of transmitting information from the shadow area to the service area.

The forward link step may include transmitting information to be transmitted from a base station in the service area using a first transmission frequency in a predetermined CDMA mobile communication service band; Receiving the first transmission frequency in the service area, converting the second transmission frequency into a second transmission frequency in a CDMA mobile communication service band, and wirelessly transmitting it; Receiving the second transmission frequency signal in the shaded area and converting the signal to the first transmission frequency; And providing a CDMA mobile communication service to a subscriber in the shaded area by using the converted first transmission frequency signal.

The reverse link step may include receiving information to be transmitted from a subscriber station in the shaded area using the third transmission frequency in a predetermined mobile communication service band; Converting the third transmission frequency received in the shaded area into a fourth transmission frequency in a mobile communication service band and wirelessly transmitting it; And receiving the fourth transmission frequency signal in the service area and converting the fourth transmission frequency signal to the third transmission frequency to provide a service to a subscriber.

The outdoor frequency converter according to the present invention for solving the above technical problem is a region (shading area) to provide a service where no base station is provided, deviating from the area (service area) where the base station is installed and serviced. An outdoor type frequency conversion apparatus for providing a CDMA mobile communication service to a CDMA mobile communication service, comprising: receiving a first transmission frequency in a predetermined CDMA mobile communication service band located in the service area and transmitted from a base station in the service area, and performing a CDMA mobile communication; Converts into a second transmission frequency in a communication service band and transmits the radio frequency; converts a fourth transmission frequency signal in a CDMA mobile communication service band transmitted from the following RU into a third transmission frequency signal in a CDMA mobile communication service band, DU for transmitting to the base station; And located in the shadowed area, receiving the second transmission frequency transmitted from the DU, converting the signal to the first transmission frequency, and transmitting the converted signal to the shadowed area subscriber station, and transmitting the third transmission frequency signal received from the shadowed area subscriber station. It is characterized in that it comprises one or more RU for converting into a four transmission frequency signal for the DU radio transmission.

In accordance with another aspect of the present invention, there is provided a DU failure detection method of an outdoor type frequency converter, wherein one transmission frequency in a predetermined mobile communication service band is different for transmitting a mobile communication service in a shaded area. A DU fault detection method of an outdoor type frequency converter including a DU converting into a frequency and located in a service area and a RU located in a shadow area and converting a frequency, the method comprising: from a base station of the service area to a terminal of the shadow area; A forward link failure detection step of detecting a failure of the DU for the signal flow; And a reverse link failure detection step of detecting a failure of the DU with respect to a signal flow from the terminal in the shadow area to the base station in the service area.

The forward link failure detecting step may include: when the waveform signal output from the base station reaches the RU via the DU, examining the waveform signal reaching the RU; And detecting the failure of the DU for the forward link by transmitting the DU failure information to the monitoring center when it is determined that the DU has failed.

The reverse link failure detection step may include detecting a DU failure for the reverse link in the DU; If a failure is detected in the DU, disconnecting a forward link; And detecting disconnection of a forward link in the RU and transmitting DU failure information to a monitoring center to detect a DU failure.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. 3 schematically illustrates a CDMA mobile communication network configuration based on a repeater for explaining the present invention, and includes a base station 310, an outdoor type frequency conversion device 330, a subscriber station 360 in a shaded area, and the like. It includes a monitoring center 370 for monitoring the failure of the outdoor frequency conversion device 330.

According to the present invention, the outdoor frequency converter (FBC) is located in a service range (service area, 300) of a base station (BTS, 310) as shown in FIG. 3 (Donor Unit, 320) ) And RU (Repeater Unit, 340) located in the center of the service area (shading area, 350) to expand.

A connection for transmitting information through radio waves from the service area 300 where the base station is installed to the shaded area 350 where the base station is not installed is called a forward link, and conversely, the service area from the shaded area 350. The connection to 300 will be referred to as a backward link.

In the case of the forward link, the DU 310 receives the first transmission frequency F1 in the CDMA mobile communication service band transmitted from the base station 310 in the service area 300, and then receives the second transmission frequency in the CDMA mobile communication service band. Convert to (F3) and transmit wirelessly. In case of the reverse link, the fourth transmission frequency (F4) signal in the CDMA mobile communication service band transmitted from the RU 340 is converted into a third transmission frequency (F2) signal in the CDMA mobile communication service band and the service area ( Transfer to base station 310 within 300. The DU 310 is operable at low power, and thus, a solar cell 322 may be used as a power supply. In some cases, it is more effective to use a battery (322) that can store the electrical energy generated by the solar cell.

In the case of the forward link, the RU 340 receives the second transmission frequency F3 transmitted from the DU 320 and converts the first transmission frequency F1 to the shadow area subscriber station 360. In the reverse link, the third transmission frequency F2 received from the shadow area subscriber station 360 is converted into a fourth transmission frequency F4 and wirelessly transmitted to the DU 320. Although only one RU 340 is illustrated in FIG. 3, a plurality of RUs may be connected as necessary.

Herein, the first to fourth transmission frequencies refer to transmission frequencies within a frequency band allocated to the CDMA mobile communication service provider. The CDMA mobile communication frequency band includes a cellular frequency band as well as a PCS frequency band. 4 illustrates a channel arrangement of a domestic personal mobile communication (PCS) provider. Table 1 and Table 2 show the frequency for each channel, Table 1 shows the mobile station transmission (base station reception) frequency, and Table 2 shows the base station transmission (mobile station reception) frequency. CDMA center frequencies are assigned at 1.25 MHz intervals.

Mobile station transmission (base station reception) frequency FA number Center frequency [MHz] FA number Center frequency [MHz] FA number Center frequency [MHz] One 1751.25 8 1761.25 15 1771.25 2 1752.50 9 1762.50 16 1772.50 3 1753.75 10 1763.75 17 1773.75 4 1755.00 11 1765.00 18 1775.00 5 1756.25 12 1766.25 19 1776.25 6 1757.50 13 1767.50 20 1777.50 7 1758.75 14 1768.75 21 1778.75

Base Station Transmit (Mobile Station Receive) Frequency FA number Center frequency [MHz] FA number Center frequency [MHz] FA number Center frequency [MHz] One 1841.25 8 1851.25 15 1861.25 2 1842.50 9 1852.50 16 1862.50 3 1843.75 10 1853.75 17 1863.75 4 1845.00 11 1855.00 18 1865.00 5 1846.25 12 1856.25 19 1866.25 6 1847.50 13 1857.50 20 1867.50 7 1848.75 14 1858.75 21 1868.75

Meanwhile, a method of providing a CDMA mobile communication service for eliminating the shadow area based on the above configuration will be described. First, in the case of the forward link, when the base station BT, 310 located in the service area 300 transmits an RF signal F1, the RF signal F1 is transmitted by the DU 320 located in the service area 300. Received and frequency converted to F3. Then, the frequency-converted signal to F3 by the DU 320 is received by the RU 340 located in the shadow area 350, converted into an RF signal F1, and transmitted to the subscriber station 360 in the shadow area. do.

In case of the reverse link, the RF signal F2 to be transmitted from the subscriber station 360 in the shaded area 350 is received by the RU 340 located in the shaded area 350 and converted into frequency F4. do. The frequency-converted F4 is wirelessly transmitted by the RU 340 to the DU 320 in the service area 300. The DU 320 then receives the F4 wirelessly transmitted by the RU 340, converts it to F2, and forwards it to the base station 310 in the service area.

Meanwhile, a method of detecting a failure of the DU 320 and the RU 340 of the outdoor type frequency converter 330 will be described. In this case, the DU 320 is not connected to the monitoring center 370 by wire because it is installed on a top of a high mountain. First, forward link failure detection of the DU 320 is possible in a conventional manner. That is, when the CDMA waveform signal output from the base station 310 reaches the RU 340 in the shaded region via the DU 320, the waveform signal reached to the RU 340 is examined. If it is determined that the test result is a failure, that is, if the waveform reached or if the distortion is significantly distorted, information indicating that the DU 320 is a failure is transmitted to the monitoring center 370 to detect a failure of the DU for the forward link. .

And the reverse link failure detection of the DU 320 first detects the DU failure for the reverse link in the DU itself. Then, if a reverse link failure is detected, the forward link is disconnected. The DU failure is then detected in the same manner as the forward link DU failure detection described above. That is, the RU 340 of the shaded area 350 detects the disconnection of the forward link and transmits the DU failure information to the monitoring center 370 to detect the DU failure.

The method for providing a mobile communication service to a shadow area according to the present invention enables to provide a mobile communication service to a subscriber station in a shadow area at a low cost.

And the outdoor frequency converter can be installed in open areas such as highways.

In addition, since the DU of the outdoor frequency converter can be used with low power, a solar cell can be used as a power supply. In addition, by transmitting and receiving a signal through the conversion between the transmission frequency in the service band can be used freely without frequency interference between up and down.

Claims (6)

A method of providing a CDMA mobile communication service to an area (shading area) where a base station is to be provided and is provided out of an area (service area) where a base station is installed and serviced, A forward link step of transmitting information from the service area to a shadow area; And A reverse link step of transmitting information from the shadow area to the service area, The forward link step Transmitting information to be transmitted by a base station in the service area using a first transmission frequency in a predetermined CDMA mobile communication service band; Receiving the first transmission frequency in the service area, converting the radio frequency into a second transmission frequency of a predetermined FA number different from the FA number of the first transmission frequency in the CDMA mobile communication service band and transmitting the radio frequency; Receiving the second transmission frequency signal in the shaded area and converting the signal to the first transmission frequency; And Providing a CDMA mobile communication service to a subscriber in the shadow area by using the converted first transmission frequency signal, The reverse link step Receiving information to be transmitted from the subscriber station in the shaded area by using a third transmission frequency in a predetermined mobile communication service band; Converting the third transmission frequency received in the shaded area into a fourth transmission frequency of a predetermined FA number that is different from the FA number of the third transmission frequency in the CDMA mobile communication service band and performing radio transmission; And And receiving the fourth transmission frequency signal in the service area and converting the fourth transmission frequency signal to the third transmission frequency to provide a service to a subscriber. The method of claim 1, wherein the CDMA mobile communication service band A CDMA mobile communication service providing method for a shadow area subscriber, characterized in that it is a personal communication service (PCS) frequency band. The method of claim 1, wherein the CDMA mobile communication service band A CDMA mobile communication service providing method for a shadow area subscriber, characterized in that the cellular frequency band. In the outdoor frequency conversion apparatus for providing a CDMA mobile communication service to the area (shading area) to provide a service that does not have a base station installed, away from the area (service area) where the base station is installed and serviced, A predetermined FA number which is located in the service area and receives a first transmission frequency in a predetermined CDMA mobile communication service band transmitted from a base station in the service area and is different from the FA number of the first transmission frequency in the CDMA mobile communication service band Converts to the second transmission frequency of the wireless transmission, converts the fourth transmission frequency signal in the CDMA mobile communication service band transmitted from the following RU to the third transmission frequency signal in the CDMA mobile communication service band, and transmits it to the base station in the service area. DU to; And Located in the shadowed area, receives the second transmission frequency transmitted from the DU, converts it to the first transmission frequency and transmits it to the shadowed area subscriber station, and transmits the third transmission frequency signal received from the shadowed area subscriber station; And at least one RU for converting into a fourth transmission frequency signal having a predetermined FA number different from the FA number of the transmission frequency and transmitting the DU wirelessly. The method of claim 4, wherein the DU is An outdoor type frequency converter comprising a solar cell and a battery for supplying power by storing electrical energy generated from the solar cell. Outdoor type having a DU located in a service area and a RU located in a shadow area for converting one transmission frequency in a predetermined mobile communication service band to another transmission frequency for providing a mobile communication service in a shadow area. In the DU fault detection method of the frequency converter, A forward link failure detection step of detecting a failure of a DU for a signal flow from a base station in the service area to a terminal in the shadow area; And Characterized in that the reverse link failure detection step of detecting the failure of the DU for the signal flow from the terminal of the shadow area to the base station of the service area, The forward link failure detection step When the waveform signal output from the base station reaches the RU via the DU, examining the waveform signal reaching the RU; And When the inspection result is determined to be the failure of the DU, the step of transmitting the DU failure information to the monitoring center to detect whether the failure of the DU for the forward link, The reverse link failure detection step Detecting a DU failure for a reverse link in the DU; If a failure is detected in the DU, disconnecting a forward link; And And detecting a DU failure by detecting a disconnection of a forward link at the RU and transmitting DU failure information to a monitoring center.