KR20060033612A - Apparatus and method for received beam forming and automatic gain control in mobile communication base station - Google Patents

Abstract

The present invention provides a reverse reception beamforming apparatus received from a mobile terminal in a base station in a mobile communication system, comprising: analog / digital converters for converting analog signals received from a plurality of array antennas into digital signals, and the analog / digital converters; Pre-gain controllers for controlling a received signal having a large dynamic range among the signals output from the transducers to have a stable power within a predetermined range, and a weight vector is applied to the signals output from the pre-gain controllers, respectively. And a beam combiner to form and a combiner to combine the received signals to which the weight vector is applied, an automatic gain controller to stabilize the signal output from the combiner within a predetermined range, and to demodulate the signal output from the automatic gain controller. Consists of a demodulator It characterized.

Beamforming, Automatic Gain Control (AGC)

Description

Apparatus and Method for Received Beam Forming and Automatic Gain Control in Mobile Communication Base Station}             

1A is a block diagram of an automatic gain control and reception beamforming apparatus according to a first embodiment of the present invention;

1B is a signal flowchart illustrating a method for automatic gain control and a reception beam forming according to a first embodiment of the present invention;

2A is a block diagram of an automatic gain control and reception beamforming apparatus according to a second preferred embodiment of the present invention;

FIG. 2B is a signal flowchart for explaining an automatic gain control and a reception beamforming method according to a second embodiment of the present invention; FIG.

3A is a block diagram of an automatic gain control and reception beamforming apparatus according to a third embodiment of the present invention;

3B is a signal flow diagram illustrating an automatic gain control and a reception beamforming method according to a third embodiment of the present invention;

4A is a graph illustrating a simulation result using a Uniform Linear Array (ULA) array antenna type in a fixed beam method in the first and third embodiments of the present invention;

Figure 4b is a graph of the simulation results using a uniform circular array (UCA) array antenna type in a fixed beam method in the first and third embodiments of the present invention,

4C is a performance graph of data rate in a 30 km / h fading environment of an EV-DO reverse link without beamforming technology; FIG.

5a is a diagram illustrating a type of uniform linear array (ULA) antenna applied to a simulation;

Figure 5b shows the Uniform Circular Array (UCA) array antenna type applied to the simulation.

FIG. 6 is a view showing simulation results using the fixed beam method in the first and third embodiments of the present invention. FIG.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a beamforming apparatus and method for a mobile communication system, and more particularly, to a reverse receiving beamforming apparatus and method from a mobile terminal to a base station in a mobile communication system.                         

Recently, the rapid increase in the number of users due to the generalization of mobile communication technology has caused the capacity problem of the mobile communication system. In order to secure as much subscriber capacity as possible with a predetermined frequency bandwidth, a frequency division multiple access method (FDMA) in which each subscriber uses each frequency channel by dividing a given frequency bandwidth into frequency channels necessary for communication. In addition, a time division multiple access (TDMA) method in which each subscriber uses only a predetermined time for one frequency channel has been used. In addition, a code division multiple access scheme has been developed that distinguishes each subscriber by using the same frequency band but assigning a different cipher to each subscriber.

However, there are limitations in accommodating the necessary subscribers only by the method of increasing the use efficiency of a given frequency band by the multiple access technologies as described above, and the proposed concept to overcome this limitation of capacity is cellular. Cellular is a mobile communication method that divides a service area into several small areas, that is, cells, so that two cells far enough apart can use the same frequency band to increase the number of spatially distributed channels to secure sufficient subscriber capacity. Say Here, if the base station antenna is multi-sectored (Multi Sector), the base station call capacity can be further increased.

In addition to multi-sectorization, a technique that has emerged as a method of increasing the capacity of a system is a signal processing technique using beamforming. The basic principle of beamforming is to multiply a plurality of antenna elements in a specific form and multiply the output of each antenna element by a weight vector to extract an antenna signal in the direction of a desired mobile terminal. In other words, it gives a large gain in the direction of the desired signal and a small gain in the other direction so that the transmitting and receiving end gets more power for the same transmission power. In other words, where there is a desired subscriber, reinforcement interference occurs, and the unwanted subscriber acts as an interference signal to cancel the interference. The signal processing of the beamforming apparatus in a mobile communication system consisting of a terminal station and a base station is mainly considered in the base station due to factors such as its physical size and required calculation amount, and can be applied to both the reverse direction and the forward direction of the base station. .

In addition, a signal received by a base station in a mobile communication environment has a large dynamic range. Therefore, the base station needs to perform an automatic gain control (AGC) so that the received signal has a stable power within a predetermined level.

Accordingly, an object of the present invention for solving the above problems is an apparatus for implementing a reverse link stage of a base station system to which Automatic Gain Control (AGC) and Beamforming technology are applied; In providing a method.

The present invention for achieving the above object is in the reverse receiving beam forming apparatus received from a mobile terminal in a base station in a mobile communication system, analog / digital for converting analog signals received from a plurality of array antennas to digital signals, respectively Applying a weight vector to the converters, the automatic gain controllers to ensure that the signals received for each of the array antennas output from the analog / digital converters have stable power within a predetermined range, and the signals output from the automatic gain controllers. Beam combiners for forming a beam, a combiner for combining received signals to which a weight vector is applied, and a demodulator for demodulating a signal output from the combiner.

In order to achieve the above object, the present invention provides a method for forming a reverse reception beam received from a mobile terminal in a base station in a mobile communication system, the method comprising: converting analog signals received from a plurality of array antennas into digital signals, respectively; An automatic gain control process for having the digitally converted signals having a stable power within a predetermined range, a process of forming a beam by applying a weight vector to the automatic gain controlled signals, and a combination of the received signals to which the weight vector is applied. And demodulating the combined signal.

The present invention for achieving the above object is in the reverse receiving beam forming apparatus received from a mobile terminal in a base station in a mobile communication system, analog / digital for converting the analog signals received from a plurality of array antennas to a digital signal, respectively A beamformer for forming a beam by applying a weight vector to the transducers, signals output from the analog / digital converters, a combiner for combining the received signals to which the weight vector is applied, and a signal output from the combiner And a demodulator for demodulating a signal output from the automatic gain controller and an automatic gain controller to have a stable power within a predetermined range.

In order to achieve the above object, the present invention provides a method for forming a reverse reception beam received from a mobile terminal in a base station in a mobile communication system, the method comprising: converting analog signals received from a plurality of array antennas into digital signals; Forming a beam by applying a weight vector to each of the digitally converted signals, combining the received signals to which the weight vector is applied, and automatic gain control to have the combined signal have a stable power within a predetermined range. And demodulating the automatic gain controlled signal.

The present invention for achieving the above object is in the reverse receiving beam forming apparatus received from a mobile terminal in a base station in a mobile communication system, analog / digital for converting the analog signals received from a plurality of array antennas to a digital signal, respectively Converters, pre-gain controllers for controlling a received signal having a large dynamic range among the signals output from the analog-to-digital converters to have a stable power within a predetermined range, and to the signals output from the pre-gain controllers. Beamformers for forming a beam by applying a weight vector to each other, a combiner for combining the received signals to which the weight vector is applied, an automatic gain controller for having a stable power within a predetermined range of the signal output from the combiner, the automatic Output from the gain controller And a demodulator for demodulating the signal.

In order to achieve the above object, the present invention provides a method for forming a reverse reception beam received from a mobile terminal in a base station in a mobile communication system, the method comprising: converting analog signals received from a plurality of array antennas into digital signals, respectively; Pre-gain controlling a received signal having a large dynamic range among the digitally converted signals to have a stable power within a predetermined range, forming a beam by applying a weight vector to the pre-gain controlled signals, respectively; The received signals to which the weight vector is applied are composed of a process of combining, an automatic gain control process of having the combined signal having a stable power within a predetermined range, and a process of demodulating the signal of the automatic gain controlled signal. do.

Hereinafter, the detailed operation and structure of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that reference numerals and like elements among the drawings are denoted by the same reference numerals and symbols as much as possible even though they are shown in different drawings. In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

The present invention proposes a technique for applying automatic gain control (AGC) and beamforming to the reverse link stage of a base station system.

Herein, three embodiments for implementing the bar proposed by the present invention will be presented.                     

The first embodiment is a method of beamforming after performing automatic gain control (AGC) on a signal received for each array antenna.

The second embodiment is a method of performing Automatic Gain Control (AGC) after beamforming.

The third embodiment is a pre-gain controller (Pre Gain Controller) to control to have a stable power in a roughly defined level (Rough) to perform beamforming (Beamforming) and automatic gain control (AGC) This is how it is done.

First, a first embodiment will be described with reference to FIGS. 1A and 1B.

1A is a diagram illustrating an automatic gain control and beamforming apparatus according to a first embodiment of the present invention.

Referring to FIG. 1A, the analog / digital converter 111 converts an analog signal received from array antennas into a digital signal and outputs the digital signal. The automatic gain controller (AGC) 112 performs automatic gain control of the digital signal output from the analog / digital converter 111 so that the signals received for each array antenna are stable within a predetermined level. have power). The beam forming unit 113 applies a weight vector to a signal output from the automatic gain control unit 112 to perform beamforming by beamforming. The combiner 114 combines and outputs the received signals to which the weight vector is applied, and the demodulator 115 demodulates and outputs the combined signal output from the combiner 114.                     

1B is a signal flowchart illustrating an automatic gain control and beamforming method according to a first embodiment of the present invention.

Referring to FIG. 1B, in step 121, signals are received from array antennas. In step 122, the analog signals received from the antennas are converted into digital signals. In operation 123, an automatic gain control (AGC) is performed so that signals received for each antenna have stable power within a predetermined level. In step 114, a weight vector is applied to the received signal that has passed through the AGC, and in step 115, the beam is formed. In step 116, the received signals are combined, and in step 117, demodulation is performed.

In the first embodiment, the signal that has undergone the automatic gain control (AGC) is different from the power level of the actually received signal. When the beamforming technique is applied to the signal, the received signal is distorted. Can be. Accordingly, in order to prevent distortion of the received signal as described above, a second embodiment as shown in FIGS. 2A and 2B is proposed.

2A is a diagram illustrating an automatic gain control and beamforming apparatus according to a second embodiment of the present invention.

Referring to FIG. 2A, the analog / digital converter 211 converts an analog signal received from array antennas into a digital signal and outputs the digital signal. The beam forming unit 212 performs beamforming by applying a weight vector to the signal output from the analog / digital converter 211 and outputs the result. The combiner 213 combines and outputs the received signals to which the weight vector is applied, and an automatic gain controller (AGC) 213 performs automatic gain control of the digital signal output from the combiner 214. By doing so, the signals received for each array antenna have a stable power within a predetermined level. The demodulator 215 demodulates and outputs the combined signal output from the combiner 214.

2B is a signal flowchart illustrating an automatic gain control and beamforming method according to a second embodiment of the present invention.

FIG. 2B receives a signal from array antennas in step 221. In step 222, the analog signals received from the antennas are converted into digital signals. In operation 223 and 224, a beam is formed by applying a weight vector to the received signal. In step 225, the received signal is combined, and in step 226, the automatic gain control (AGC) is performed to demodulate the received signal having a stable power within a predetermined level.

 In the second embodiment as described above, the method of performing AGC after beamforming can prevent distortion of the received signal, but the dynamic range of the received signal is too large to be applied to the signal. When applying beamforming technology, complexity may increase. Accordingly, a third embodiment as shown in FIGS. 3A and 3B is proposed.

3A is a diagram illustrating an automatic gain control and beamforming apparatus according to a third embodiment of the present invention.

Referring to FIG. 3A, the analog / digital converter 311 converts an analog signal received from array antennas into a digital signal and outputs the digital signal. The pre-gain controller 312 controls a received signal having a large dynamic range among the digital signals output from the analog / digital converter 311 so as to have stable power within a roughly defined level. . The beam forming unit 313 applies a weight vector to a signal output from the pre-gain controller 312 to perform beamforming by beamforming. The combiner 314 combines and outputs the received signals to which the weight vector is applied, and the automatic gain controller (AGC) 315 performs automatic gain control of the digital signal output from the combiner 314. By doing so, the signals received for each array antenna have a stable power within a predetermined level. A demodulator 316 demodulates and outputs a combined signal output from the combiner 314.

3B is a signal flowchart illustrating an automatic gain control and beamforming method according to a third embodiment of the present invention.

In step 321, signals are received from the array antennas. In step 322, the received analog signals are converted into digital signals (A / D). In step 323, a received signal having a large dynamic range is controlled to have a stable power within a predetermined level. In operation 324 and 325, a beam is formed by applying a weight vector to the received signal. In step 326, the received signal is combined, and in step 327, an automatic gain control (AGC) is performed to demodulate the received signal having a stable power within a predetermined level.

FIG. 4A illustrates the use of a Uniform Linear Array (ULA) array antenna type including 12 array antennas in a switched beamforming method in the first and third embodiments of the present invention. The result is a graph. In a 30km / h fading environment, the data rate is about 9.6kbps and 153.6kbps.

FIG. 4B illustrates the use of a Uniform Circular Array (UCA) array antenna type (UCA) consisting of 12 array antennas in a switched beamforming method in the first and third embodiments of the present invention. The result is a graph. In a 30km / h fading environment, the data rate is about 9.6kbps and 153.6kbps.

FIG. 4C shows performance graphs for data rates of 9.6kbps and 153.6kbps in a 30km / h fading environment of an EV-DO reverse link without beamforming technology.

FIG. 5A illustrates a Uniform Linear Array (ULA) array antenna type applied to the simulation.

5B illustrates a Uniform Circular Array (UCA) array antenna type (Array Antenna Pattern) applied to the simulation.                     

In the simulation, although the second embodiment was not simulated due to complexity, it is expected that the second embodiment will have similar results.

FIG. 6 is a table comparing the simulation results of the switched beamforming method in the first and third embodiments of the present invention. In the 30km / h fading environment, the array antenna pattern is represented by a uniform linear array (ULA) and a uniform circular array (UCA) consisting of 12 array antennas. For 9.6kbps and 153.6kbps, FER (Frame Error Rate) 5% performance is shown.

As shown in FIG. 6, a beamforming technique is a method of performing beamforming after performing AGC on a signal received for each array antenna, which is the first embodiment of the present invention. Performance improvements of about 1.1 to 1.3 dB for ULA array antenna types compared to unapplied EV-DO reverse links, and 0.9 to 2.4 dB for uniform linear array array antenna types. It shows a performance improvement. In addition, the third embodiment of the present invention, the pre-gain controller (Pre Gain Controller) is controlled to have a stable power in a roughly defined level (Level) and then beamforming (Beamforming) and automatic gain control (AGC: Automatic Gain Control) The proposed method shows the performance improvement of 1.6 ~ 1.7dB in the ULA array antenna type compared to the EV-DO reverse link without beamforming technology. Uniform Linear Array) Array antenna type shows a performance improvement of 2.4 ~ 3.9dB.

In addition, referring to FIG. 6, after controlling to have a stable power within a roughly determined level with a pre-gain controller, a third embodiment of the present invention, beamforming is performed and automatic gain control is performed. (AGC: Automatic Gain Control) is a method of performing ULA (Beamforming) after performing AGC on a signal received for each array antenna, which is the first embodiment of the present invention. Uniform linear array array antenna type shows 0.3 ~ 0.6dB performance improvement and uniform linear array array antenna type shows about 1.5dB performance improvement.

As described above, the present invention can achieve stable and excellent beamforming effect by applying the automatic gain control (AGC) and beamforming techniques to the reverse link stage of the base station system. .

Claims (6)

An apparatus for forming a reverse reception beam received from a mobile terminal at a base station in a mobile communication system, Analog / digital converters for converting analog signals received from a plurality of array antennas into digital signals, respectively; Automatic gain controllers which have a stable power within a predetermined range of the signals received for each of the array antennas output from the analog / digital converters; Beamformers for forming a beam by applying a weight vector to signals output from the automatic gain controllers; A combiner for combining the received signals to which the weight vector is applied; And a demodulator for demodulating a signal output from the combiner. A method for forming a reverse reception beam received from a mobile terminal at a base station in a mobile communication system, Converting analog signals received from a plurality of array antennas into digital signals, respectively; An automatic gain control process for each of the digitally converted signals to have a stable power within a predetermined range; Forming a beam by applying a weight vector to the automatic gain controlled signals; Combining the received signals to which the weight vector is applied; And demodulating the combined signal. An apparatus for forming a reverse reception beam received from a mobile terminal at a base station in a mobile communication system, Analog / digital converters for converting analog signals received from a plurality of array antennas into digital signals, respectively; Beamformers for forming beams by applying weight vectors to signals output from the analog / digital converters; A combiner for combining the received signals to which the weight vector is applied; An automatic gain controller which makes the signal output from the combiner have a stable power within a predetermined range; And a demodulator for demodulating a signal output from the automatic gain controller. A method for forming a reverse reception beam received from a mobile terminal at a base station in a mobile communication system, Converting analog signals received from a plurality of array antennas into digital signals, respectively; Forming a beam by applying weight vectors to the digitally converted signals; Combining the received signals to which the weight vector is applied; Automatic gain control of the combined signal to have a stable power within a predetermined range; And demodulating the automatic gain controlled signal. An apparatus for forming a reverse reception beam received from a mobile terminal at a base station in a mobile communication system, Analog / digital converters for converting analog signals received from a plurality of array antennas into digital signals, respectively; Pre-gain controllers for controlling a received signal having a large dynamic range among the signals output from the analog / digital converters to have a stable power within a predetermined range; Beamformers for forming beams by applying weight vectors to signals output from the pre-gain controllers; A combiner for combining the received signals to which the weight vector is applied; An automatic gain controller which makes the signal output from the combiner have a stable power within a predetermined range; And a demodulator for demodulating a signal output from the automatic gain controller. A method for forming a reverse reception beam received from a mobile terminal at a base station in a mobile communication system, Converting analog signals received from a plurality of array antennas into digital signals, respectively; Pre-gain controlling a received signal having a large dynamic range among the digitally converted signals to have a stable power within a predetermined range; Forming a beam by applying a weight vector to each of the pre-gain controlled signals; Combining the received signals to which the weight vector is applied; An automatic gain control process for causing the combined signal to have a stable power within a predetermined range; And demodulating the signal with the automatic gain controlled signal.

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