KR20000008276A - Base station apparatus of mobile communication system using cdma method applying active antenna - Google Patents

Abstract

PURPOSE: A mobile communication system base station apparatus using the CDMA method is provided to make the structure of the entire system simple, reduce the cost and enlarging the subscriber containing capacity. CONSTITUTION: The base station apparatus has; a transceiver unit(10) transmitting to a demodulating unit in the base station; an IDU(20) feeding and transmitting direct current power to the CDMA forward direction channel signal that is transmitted to be changed upward from the transceiver unit and transmitting the received CDMA reverse direction channel signal to the transceiver unit; and a transmission butler matrix unit(30) transmitting a beam formation signal by giving a phase difference to the CDMA forward direction channel signal.

Description

Base station apparatus of mobile communication system of CDA method using active antenna

The present invention is applied to a digital cellular system of a code division multiple access (CDMA) method by applying an outdoor active antenna having a built-in transmit / receive amplifier. A base station apparatus of a CDMA type mobile communication system employing an active antenna to implement a base station apparatus of a mobile communication system such as a " Personal Communication System " (hereinafter referred to as a " PCS "). will be.

In a base station apparatus of a mobile communication system such as a conventional CDMA DCS or PCS, an omnidirectional antenna or a sector antenna is installed outdoors, and a high power amplifier (HPA) for transmission is provided at an indoor antenna transmitter. A low noise amplifier (LNA) for receiving is connected to the antenna receiver.

As described above, when the omnidirectional antenna or the sector antenna is applied in the base station apparatus, the cable loss increases as the distance between the outdoor antenna and the indoor equipment increases, so that a high power amplifier and a low noise amplifier must be installed indoors.

As described above, since the high power amplifier and the low noise amplifier are essentially provided, the overall structure of the system is complicated and economical losses are caused.

The present invention has been made to solve the above problems, and the object of the present invention is to apply an outdoor active antenna having a built-in transmit / receive amplifier instead of an antenna installed in the conventional outdoor, so that an indoor high power amplifier and a low noise amplifier are not required. Therefore, the CDMA method using the active antenna that simplifies the structure of the entire system and reduces the cost, and increases the subscriber capacity through the increased sectorization gain by the generation of multi-beams according to the horizontal arrangement of the active antenna The present invention provides a base station apparatus of a mobile communication system.

1 is a block diagram of a base station apparatus of a CD-based mobile communication system to which the active antenna according to the present invention;

2 is a view showing a detailed configuration of the IDU of FIG.

3 is a view showing a detailed configuration of the ARM of FIG.

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

10: transceiver unit 20: IDU

21: power supply device 22 to 24: first to third bias T

30: transmitting butler matrix unit 40: receiving butler matrix unit

51-54: 1st-4th ARM 55: Dummy rod

61: transmit amplifier 62: transmit bandpass filter

63 transmitting antenna 64 receiving antenna

65: reception bandpass filter 66: reception amplifier

In the base station apparatus of the CDMA mobile communication system to which the active antenna of the present invention is applied to achieve the above object, a 4.95 MHz intermediate frequency signal that is CDMA modulated by a modulator in a base station apparatus after applying an active antenna having a built-in transmit / receive amplifier Is up-converted into a frequency signal for transmitting to a subscriber station, and a DC power is coupled to the frequency up-converted CDMA forward channel signal to transmit beamforming signals for channel signals by alpha, beta, and gamma sectors. After amplifying the signal by a certain level and removing the spurious, the signal is transmitted to the subscriber station by copying it into a space having a beam width of 30 ° through the transmitting antenna and receiving the CDMA reverse channel signal transmitted from the subscriber station through the receiving antenna. Filters only the frequency band and amplifies it by a certain level, then alpha, beta, gamma A sector-specific CDMA reverse channel signal is converted into a 4.95 MHz intermediate frequency signal and transmitted to a demodulator in the base station apparatus.

Hereinafter, a configuration and operation of a base station apparatus of a CDMA mobile communication system to which an active antenna according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a base station apparatus of a CDMA mobile communication system to which an active antenna according to the present invention is applied, and is an up / down converter configured indoors. In the base station apparatus (not shown) by upconverting the CDMA modulated 4.95MHz intermediate frequency signal to a frequency signal for transmitting to the subscriber station or downconverting the received radio frequency signal into a 4.95MHz intermediate frequency signal. Transmits by adding a direct current (DC) power to a transceiver unit 10 and a CDMA forward channel signal transmitted up-converted from the transceiver unit 10, or received a CDMA reverse channel signal The IDU (InDoor Unit) (20) for transmitting to the transceiver unit 10 as it is, and the three alpha (α), beta (β), gamma (γ) sector transmitted from the transceiver unit 10 Tx Butler Matrix 30, which transmits a beam forming signal by giving a phase difference to a CDMA forward channel signal, and a CDMA reverse channel signal according to alpha, beta, and gamma sectors. CDMA forward corresponding to one sector by amplifying a Rx Butler Matrix 40 and a beamforming signal transmitted from the Tx Butler Matrix unit 30 which are converted to the IDU 20 and transmitted to the IDU 20. First to fourth ARM (Active Radiator Module) 51 to copy the channel signal in the space of a beam having a width of 30 degrees, or to receive the radio signal of the subscriber station and transmit it to the receiving butler matrix unit 40 54) and terminating the other input / output terminals except for the input / output terminals for transmitting alpha, beta, and gamma sector channel signals in the transmission butler matrix unit 30 and the reception butler matrix unit 40. It consists of a dummy load (Dummy Load) (55).

FIG. 2 is a detailed configuration diagram of the IDU 20 of FIG. 1, which converts an AC power supplied from the outside into a DC power supply that satisfies the input conditions of the first to fourth ARMs 51 to 54. 21 and the DC power supplied from the power supply unit 21 to the CDMA forward channel signal transmitted from the transceiver unit 10 to be transmitted to the transmission butler matrix unit 30 or the receiving butler matrix unit ( And first to third bias Ts 22 to 24 for transmitting the CDMA reverse channel signal transmitted from 40 to the transceiver unit 10 as it is.

FIG. 3 is a detailed configuration diagram of the first to fourth ARMs 51 to 54 of FIG. 1, which performs a predetermined level amplification of the power of the beamforming signal for the CDMA forward channel signal transmitted from the transmission butler matrix unit 30. The transmission amplifier 61, the transmission bandpass filter 62 for removing a spurious component of the beamforming signal amplified by the transmission amplifier 61, and the spurious component is removed from the transmission bandpass filter 62. A transmission antenna 63 for copying the formed beamforming signal into a beam having a predetermined beam width and directivity angle in a space, a reception antenna 64 for receiving a radio signal transmitted from a subscriber station, and a reception antenna 64 The received bandpass filter 65 which filters only a frequency band that meets the input condition of the received amplifier with respect to the received radio signal, and a predetermined level of amplification of the power of the radio signal filtered by the received bandpass filter 65 It consists of a receiving amplifier 66, transmitting a new Butler Matrix unit 40.

The first to fourth ARMs 51 to 54 operate as array antennas in which four active antennas are arranged horizontally to form a radiation pattern such as three single beams having a beam width of 30 degrees.

Of the base station apparatus configured as described above, the transceiver unit 10 and the IDU 20 are equipment installed indoors, and the remaining components are equipment installed outdoors.

The base station apparatus configured as described above is an apparatus implemented based on three sectors of alpha, beta, and gamma.

The active antenna according to the present invention having the above configuration refers to an antenna in which an active element is incorporated to improve performance of an existing antenna, and a beam forming device such as a Butler matrix at the active antenna input terminal. ) And input a plurality of transmission channel signals through the beam forming apparatus to form a multi-beam.

The operation of the base station apparatus according to the present invention configured as described above is as follows.

First, a case of transmitting a CDMA forward channel signal from a base station apparatus to a subscriber station will be described. In the transceiver unit 10, a frequency for transmitting a CDMA modulated 4.95 MHz intermediate frequency signal to a service subscriber station in a base station apparatus modulator. Upconvert to a signal.

In this case, the DCS upconverts the intermediate frequency signal of 4.95MHz to 869 ~ 894MHz and PCS to 1840 ~ 1870MHz.

Subsequently, in the first through third biases T 22 through 24 of the IDU 20, the CDMA forward channel signals Tx1, Tx2, and Tx3 corresponding to the alpha, beta, and gamma sectors transmitted from the transceiver unit 10 are then applied. The DC power supplied from the power supply unit 21 is combined and transmitted to the transmission butler matrix unit 30.

That is, the IDU 20 combines DC power required by the first to fourth ARMs 51 to 54 to the forward channel signal divided into alpha, beta, and gamma sectors on the transmission path.

Subsequently, the transmission butler matrix unit 30 gives a phase difference with respect to the CDMA forward channel signals of the alpha, beta, and gamma sectors transmitted from the first to third biases T (22 to 24) of the IDU 20. Each beamforming signal for each of the CDMA forward channel signals is transmitted to the first to fourth ARMs 51 to 54.

The transmitter butler matrix unit 30 is also referred to as 4 × 4 butler matrix with four input / output terminals, wherein three input terminals receive CDMA forward channel signals for alpha, beta, and gamma sectors, and the other one input terminal. Termination is performed with the dummy rod 55.

That is, the transmission butler matrix unit 30 transmits the respective beamforming signals for three CDMA forward channel signals through all output terminals regardless of the number of signals input to the input terminals. To 54).

Subsequently, in the first to fourth ARMs 51 to 54, the transmission amplifier 61 amplifies a predetermined level of power of the beamforming signal for the CDMA forward channel signal transmitted from the transmission butler matrix unit 30, and transmits the signal. The spurious component of the beamforming signal amplified by the transmission amplifier 61 is removed through the bandpass filter 62. Finally, the spurious component is removed from the transmission bandpass filter 62 through the transmission antenna 63. The beamforming signal is radiated to a space at a beam width of 30 ° and a directivity angle to be transmitted to the subscriber station.

That is, the beam forming signals corresponding to the alpha, beta, and gamma sectors are respectively radiated to the beams having a beam width of 30 degrees, that is, a beam width of 90 degrees in total, through the transmission antenna 63.

At this time, the beam width radiated from the first to fourth ARMs 51 to 54 by the beam forming signal of the transmission butler matrix unit 30 is aligned with the radiation patterns of the first to fourth ARMs 51 to 54. It is determined according to the number of the first to fourth ARMs 51 to 54, and the directing angle of each beam is determined by the transmission butler matrix unit 30.

Next, a case in which a CDMA reverse channel signal is transmitted from a subscriber station to a base station apparatus will be described. In the first to fourth ARMs 51 to 54, a radio signal is received from a subscriber station through a receive antenna 64 and received. The band pass filter 65 filters only the frequency bands corresponding to the input conditions of the receiver amplifier 66 with respect to the radio signal. Then, the power of the radio signal filtered by the receive band pass filter 65 is received through the receiver amplifier 66. It amplifies a predetermined level and transmits it to the receiving butler matrix unit 40.

Subsequently, a 4 × 4 butler matrix is used, and in the receiving butler matrix unit 40 in which one output terminal is connected to the dummy rod 55, the receiving amplifier 66 in the first to fourth ARMs 51 to 54 is used. The transmitted radio signal is converted into a CDMA reverse channel signal for each alpha, beta, gamma sector, and transmitted to the IDU 20.

Thereafter, the IDU 20 receives the CDMA reverse channel signal transmitted from the reception butler matrix unit 40 as it is, regardless of the operation of the power supply 21 and the first to third biases T 22 to 24. Transmit to the unit 10.

Accordingly, the transceiver unit 10 converts a CDMA reverse channel signal transmitted from the IDU 20, that is, a signal of 824 to 849 MHz for DCS and 1750 to 1780 MHz for PCS to an intermediate frequency of 4.95 MHz. Send it to my demodulator.

The radiation pattern of the active antenna of the present invention is composed of three single beams having a beam width of 30 degrees and has a total coverage of 90 degrees, whereas a conventional sector antenna has a total of 360 degrees propagation region in alpha, beta. And a propagation area of 120 ° divided into three gamma sectors.

Accordingly, the present invention can cover 360 ° through the four transmit / receive antennas of the first to fourth ARMs 51 to 54, and eventually transmit and receive a CDMA channel by dividing a total propagation area of 360 ° into 12 sectors. Therefore, the increased sectorization gain can be expected as compared with the conventional CDMA system employing the sector antenna.

As described above, according to the present invention, an active antenna having a built-in transmit / receive amplifier is applied to a base station apparatus, thereby eliminating the need for a high power amplifier or a low noise amplifier installed in a conventional base station indoor, thereby simplifying the overall base station system and reducing costs. As the propagation area is controlled by 12 sectors by 30 °, there is an effect that the capacity of the subscriber can be increased in anticipation of increased sectorization gain.

Claims (3)

In the base station apparatus of the mobile communication system such as DCS or PCS implemented based on the three sectors of alpha, beta, gamma, Transceiver unit 10 for up-converting the CDMA modulated intermediate frequency signal by the modulation unit in the base station apparatus to the frequency signal for transmitting to the subscriber station or down-converting the received radio frequency signal into the intermediate frequency signal and transmitting the demodulation unit in the base station apparatus (10). And an IDU 20 that adds DC power to the CDMA forward channel signal transmitted upconverted by the transceiver unit 10 and transmits the received CDMA reverse channel signal to the transceiver unit 10 as it is. A transmission butler matrix unit 30 for transmitting a beamforming signal by giving a phase difference to three CDMA forward channel signals for each of the alpha, beta, and gamma sectors transmitted from the transceiver unit 10; A reception butler matrix unit 40 for converting a beta and gamma sector CDMA reverse channel signal to be transmitted to the IDU 20; Incorrectly amplifies the beamforming signal transmitted from the matrix unit 30 to copy the CDMA forward channel signal corresponding to one sector in a space having a beam width of 30 degrees, or to receive the radio signal of the subscriber station Alpha, beta, and gamma sector channel signals are transmitted by the first to fourth ARMs 51 to 54 transmitted to the butler matrix unit 40, and the transmission butler matrix unit 30 and the receiving butler matrix unit 40. The base station apparatus of the CD-based mobile communication system to which the active antenna is applied, characterized in that it consists of a dummy rod (55) for terminating the other one input and output terminal except for the input and output terminal for. The power supply apparatus 21 according to claim 1, wherein the IDU 20 converts an external AC power supply to a DC power supply that satisfies the input conditions of the first to fourth ARMs 51 to 54, and supplies the same. The DC power supplied from the power supply unit 21 is coupled to the CDMA forward channel signal transmitted from the transceiver unit 10 and transmitted to the transmission butler matrix unit 30 or transmitted from the reception butler matrix unit 40. The base station apparatus of the CD-based mobile communication system using the active antenna, characterized in that the first to third bias T (22 to 24) for transmitting the CDMA reverse channel signal to the transceiver unit 10 as it is. The transmission amplifier according to claim 1, wherein the first to fourth ARMs 51 to 54 are configured to transmit a predetermined level of amplification of the power of the beamforming signal for the CDMA forward channel signal transmitted from the transmission butler matrix unit 30. 61), a transmission bandpass filter 62 for removing the spurious component of the beamforming signal amplified by the transmission amplifier 61, and a beamforming signal from which the spurious component is removed from the transmission bandpass filter 62 is determined. Regarding the transmitting antenna 63 which radiates in the space with a beam having a beam width and a direction angle, the receiving antenna 64 for receiving the radio signal transmitted from the subscriber station, and the radio signal received by the receiving antenna 64 A reception bandpass filter 65 for filtering only a frequency band meeting the input condition of the reception amplifier, and a predetermined level amplified power of the wireless signal filtered by the reception bandpass filter 65 to receive the reception butler mat A base station apparatus of a mobile communication system of a CD-A method using an active antenna, characterized in that consisting of a receiving amplifier (66) for transmitting to the lix unit (40).