KR100959054B1 - Apparatus for a RF wired MIMO link tester - Google Patents

Abstract

The present invention relates to a wired link testing apparatus for checking the performance of a multi-antenna system, in which a wireless channel environment for a multi-antenna system is simulated using a wired link, And to provide a wired link test apparatus for checking the performance of a multi-antenna system.

To this end, the present invention relates to a wired link testing apparatus comprising: a simulator for constructing a wired link corresponding to a radio link for a multi-antenna system and simulating a radio link characteristic using each variable element disposed on the wired link, Way; And control means for previously storing a predetermined value of the variable element according to the state change time and the number of state changes to indicate the radio link characteristic and controlling the variable element according to a predetermined value of the variable element.

Wireless LAN environment, wired link test equipment, wireless link characteristics, path loss, fast fading,

Description

[0001] The present invention relates to a wired link test apparatus for checking the performance of a multi-

The present invention relates to a wired link test apparatus for checking the performance of a multi-antenna system, and more particularly, to a wireless link test apparatus for testing the performance of a multi-antenna system, The present invention relates to a wired link test apparatus for checking the performance of a multi-antenna system.

The present invention was derived from research conducted as part of the IT new growth engine core technology development project of the Ministry of Information and Communication and the Korea Information Society Agency. [Assignment number: 2005-S-404-12, title: Development of 3G Evolution Wireless Transmission Technology ].

In the process of developing next generation mobile communication system, it is necessary to check the system through indoor wire test before outdoor wireless interworking test.

Therefore, in the case of a next generation mobile communication system that is aiming at high-speed multimedia communication using a wide bandwidth and multiple antennas, a method for an indoor wire test capable of performing the above-described process for a multi-antenna system should be considered.

In the conventional single-antenna system, the system is checked in the ideal radio channel environment from the modem point of view simply by connecting the transmission antenna port and the reception antenna port by wire. In this case, we could simply check whether the system was operating.

However, in the case of a multi-antenna system, the above-described method may not be applied depending on the configuration of the transmission multi-antenna and the reception multi-antenna.

Also, even if the above-mentioned wire testing method can be applied because the number of transmitting multi-antennas is the same as that of receiving multi-antennas, only the simple system operation is confirmed as in the single antenna system test. Above all, in this case, the test is conducted in a physically uncomfortable situation in which a signal transmitted from one transmitting antenna is received by only one receiving antenna.

Also, in the case of the conventional single antenna system, the system can be verified by a wired line using a channel simulator capable of simulating a general wireless channel.

The channel simulator down-converts the signal transmitted by the transmission system, simulates the influence of the radio channel by the digital signal processing in the baseband, up-converts the up-converted signal to the reception system . System verification using this can be a system verification in all situations, but it can be more than necessary, and its structure is complicated and expensive.

In particular, in the case of a multi-antenna system, there is a disadvantage that a more complicated and costly channel simulator is required to verify the system with the channel simulator as described above.

Therefore, when the conventional wired test methods used for checking a single antenna system are applied to a multi-antenna system, it is difficult to simply check whether a system is operating in a physically difficult situation or to implement a device for a wired test It is an object of the present invention to solve such a problem.

That is, the present invention is advantageous in comparison with a channel simulator for checking a multi-antenna system in terms of implementation and cost, but also has a simple system operation check, a system automatic gain control function check, and a hand- The present invention provides a wire link test apparatus having a function check function.

Accordingly, the present invention provides a method for checking the performance of a multi-antenna system in a room prior to an outdoor wireless interworking test by simulating a wireless channel environment for a multi-antenna system using a wired link, Link test apparatus.

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention which are not mentioned can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. It will also be readily apparent that the objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

According to an aspect of the present invention, there is provided a wired link testing apparatus comprising: a wired link corresponding to a wireless link for a multi-antenna system; and a plurality of variable elements disposed on the wired link, Simulating means for simulating; And control means for previously storing a predetermined value of the variable element according to the state change time and the number of state changes to indicate the radio link characteristic and controlling the variable element according to a predetermined value of the variable element.

The present invention has the effect of simulating a situation in which a signal transmitted from one transmission antenna is transmitted to all reception antennas by configuring a wired link corresponding to a radio link for a multiple antenna system.

In addition, the present invention has the effect that the attenuation and phase characteristics of each wired link can be made equal to that of each wireless link by controlling the variable elements located on each wired link in accordance with the characteristics of the wireless link to be simulated.

Thus, the present invention can simulate any radio channel having no frequency selectivity, and it is possible to perform the following system check according to the radio channel selection to be simulated.

First, the present invention can be applied to a wired link testing apparatus in which path-loss is fixed, fast-fading has no time-selectivity and frequency-selectivity, So that the simple system operation can be checked.

Second, the present invention can check the real-time automatic gain control function by simulating the wireless channel, in which the path loss of the wired link tester is fixed and the fast fading has only time-varying characteristics.

Third, the present invention can check the handover function by causing the path loss of the wired link testing apparatus to change with time and to simulate wireless channels having only the time-varying characteristic of the fast fading.

Further, the present invention has a simpler structure and less cost than the channel simulator.

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings, Can be easily performed. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of an embodiment of a wire link testing apparatus (hereinafter referred to as "wire link testing apparatus") 120 for checking the performance of a multi-antenna system according to the present invention.

1, a wired link testing apparatus 120 is connected to a base station (i.e., a first base station 111 and a second base station 112), a terminal 130, and an external computer 140, .

In the present invention, unlike the conventional channel simulator, the RF signal of the multi-antenna system to be subjected to the wire test is directly attenuated and phase-shifted based on the fact that the radio channel is actually attenuated and phase shifted to the RF signal, .

However, in the present invention, since it is difficult to implement a time delay in the RF band for a multi path, a wired link corresponding to a multi-path is not configured. Accordingly, the wired link testing apparatus according to the present invention can not simulate a radio channel having frequency selectivity.

The wired link testing apparatus 120 includes a pest fading simulation unit 200, a path loss simulation unit 300, and a control unit 600.

The pest fading simulation unit 200 corresponds to 16 radio links for a maximum 4 x 4 multi-antenna system, so that the wired link testing apparatus constitutes 16 wired links. As a result, it is simulated that the RF signal transmitted from one transmission antenna is received by all of the reception antennas.

Also, the pest fading simulation unit 200 changes characteristics of the variable attenuator and the variable phase shifter, which are located inside, according to a control signal of the control unit 600 to simulate fast fading characteristics.

The path loss simulation unit 300 forms 16 wired links together with the pest fading simulation unit 200 and changes the variable attenuator characteristic located in the path loss simulation unit 300 according to a control signal of the control unit 600, Simulate path loss characteristics.

The control unit 600 stores in advance a value for simulating the characteristics of the wireless link (i.e., the attenuation characteristic and the phase characteristic), and controls the pest fading simulation unit 200 and the path loss simulation unit 300 accordingly. At this time, a value for simulating the radio link characteristic stored in the control unit 600 is provided from the external computer 140. [

In FIG. 1, for the convenience of explanation, an example is shown in which a wired link testing apparatus 120 can configure 4 × 4 (ie, 16) wired links to check the performance of a maximum 4 × 4 multi-antenna system And those skilled in the art will readily understand that the present invention is not limited thereto.

The base stations 111 and 112 and the terminal 130 refer to a multi-antenna system to be subjected to a wired test.

The external computer 140 determines the characteristics of the wireless link to be simulated by the wired link testing apparatus and generates the control values of the variable element to simulate the characteristics of the wireless link.

2 is a block diagram of an embodiment of a pest fading simulation unit 200 according to the present invention.

As shown in FIG. 2, the pest fading simulation unit 200 simulates a situation where an RF signal transmitted from one transmission antenna is transmitted to all reception antennas using a 4-way synthesizer / distributor. That is, the pest fading simulation unit 200 corresponds to 16 radio links for a maximum 4 x 4 multi-antenna system, so that the wired link testing apparatus forms 16 wired links.

The fast fading simulation unit 200 simulates the fast fading characteristics by changing the characteristics of the variable phase shifter 211 and the variable attenuator 212 located inside the variable phase shifter 211 according to the control signal of the controller 600 . For this purpose, the pest fading simulation unit 200 is provided with a DAC (digital-to-analog converter) (DAC) for converting the digital control signal of the control unit 600 into an analog control voltage for controlling the variable elements (i.e., the variable phase shifter 211 and the variable attenuator 212) Digital-Analog Converter) and an RC filter 213 'are connected to each variable element.

3 is a block diagram of an embodiment of a path loss simulation unit 400 according to the present invention.

3, the path loss simulation unit 400 includes a fixed path loss simulation unit 310, a variable path loss simulation unit 320, and an uplink and downlink path loss correction unit 330, The attenuation value of the entire system 400 is related to the path loss simulated by the test apparatus.

The fixed path loss simulator 310 includes a variable attenuator 321 of the variable path loss simulator 320 in the path loss simulator 300 and a variable phase shifter 321 of the pest fading simulator 200 211 and the variable attenuator 212) due to the inter-modulation distortion. That is, the fixed path loss simulation unit 310 adjusts the power level of the RF signal input to the active element to be small, thereby reducing the degree of signal distortion due to intermodulation distortion of the wired link tester 120.

The variable path loss simulator 320 changes the attenuation value of the path loss simulator 400 by changing the characteristic of the variable attenuator 321 according to the control signal of the controller 600. [

Although not shown in FIG. 3, the variable path loss simulator 320 is provided with a DAC (Digital-to-Analog Converter) 322 for converting a digital control signal of the controller 600 into an analog control voltage for controlling a variable element (i.e., the variable attenuator 321) Analog converter) and an RC filter 322 '(see FIG. 6B to be described later) are connected to each variable element.

The uplink and downlink path loss corrector 330 corrects the uplink (UL) using the 'structure using the circulator and the fixed attenuator 331' to perform uplink and downlink : DL).

That is, as shown in FIG. 4, which will be described later, it is assumed that the base station itself attenuates the transmission power in order to reduce signal distortion due to intermodulation distortion of the wired link testing apparatus 120, The uplink and downlink path loss corrector 330 corrects the attenuation of the uplink and the downlink to be equal to the attenuation of the downlink.

The uplink and downlink path loss corrector 330 receives the signals from the two base stations (i.e., the first base station 111 and the second base station 112) to one terminal 130, To be transmitted to the two base stations (i.e., the first base station 111 and the second base station 112). The wired link tester 120 can then calculate the path loss between the first base station 111 and the terminal 130 and the path loss between the second base station 112 and the terminal 130 as shown in FIG. In the case of simulating, the handover test becomes possible.

4 is an exemplary diagram illustrating a power budget of the pest fading simulation unit 200 of FIG. 2 and the path loss simulation unit 300 of FIG. 3. FIG. 5 is a diagram illustrating an example of a power budget And FIG.

4, the variable attenuator 212 in the pest fading simulation unit 200 has a variable range of 30 dB and the variable attenuator 321 in the path loss simulation unit 300 has a variable range of 60 dB . Hereinafter, it is assumed that the variable phase shifter 211 in the pest fading simulation unit 200 has a variable range of 360 degrees.

As shown in FIG. 5, it is assumed that the base station transmission power is "46 dBm" and the proper reception power of the terminal is "-90 dBm to -30 dBm".

The minimum attenuation value 89 dB of the wired link testing apparatus 120 is associated with the minimum path loss simulated by the wired link testing apparatus 120. Based on this, the controller 600 changes the attenuation characteristic of the variable path loss simulator 320 in the path loss simulator 300 within a range of 60 dB to simulate the path loss characteristic.

In addition, the controller 600 may vary the attenuation and phase characteristics of the pest fading simulator 200 within the range of 30 dB and 360, respectively, to simulate the pest fading characteristics.

6A is a block diagram of an embodiment of the control unit 600 according to the present invention. FIG. 6B is a diagram illustrating a connection between the control signal of the control unit of FIG. 6A and the pest fading simulation unit 200 and the path loss simulation unit 300 Fig.

As shown in FIG. 6A, the controller 600 includes a controller 610, a field programmable gate array (FPGA) 620, and a memory 630.

Before describing the function of each component, the channel scenario and the operation scenario will be described as follows.

The channel scenario is generated by the external computer 140 and refers to the characteristics of the radio channel to be simulated. That is, the channel scenario means the attenuation characteristic and the phase characteristic according to the time simulated by the pest fading simulation unit 200 and the path loss simulation unit 300.

The operation scenario means the actual DAC value of each variable element to represent the attenuation characteristic and the phase characteristic of the channel scenario to be simulated by the pest fading simulation unit 200 and the path loss simulation unit 300. [

Specifically, when the hardware is completed, the wired link testing apparatus 120 measures wired link attenuation characteristics and phase characteristics according to DAC values for all variable elements. From this measurement result, a look-up table indicating " DAC value for indicating desired attenuation and phase " is created. That is, the operation scenario is generated by applying the lookup table created as described above to the channel scenario, and is used to represent the attenuation characteristic and phase characteristic to be simulated by the pest fading simulation unit 200 and the path loss simulation unit 300, Means the DAC value of each variable element according to the state change time and the state change frequency.

Hereinafter, functions of the respective components will be described with reference to FIG. 6A.

The controller 610 reads the operation scenario provided from the external computer 140 and stores the DAC value of each variable element according to the state change time and the number of state changes in the memory 630 via the FPGA 620. [ At this time, the controller 310 stores 'state change time' and 'state change frequency' of each variable element recorded in the operation scenario in the memory in the FPGA 620.

In other words, the controller 610 reads the operation scenario and stores it in the memory 630 because the specific part of the operation scenario corresponds to the DAC value according to the state change time and the number of state change times of the specific variable element, Which is stored in each memory. To this end, the controller 610 controls the FPGA 620 such that each part of the operational scenario is stored in its memory 630.

Further, the controller 610 instructs start and stop of the wired link testing apparatus 120 when using the apparatus.

The FPGA 630 receives the start command from the controller 610 and outputs the DAC value of the variable element stored in the memory 630 to the fade fading simulation unit 200 or the path loss simulation unit 300 (I.e., the DAC and RC filters 213 and 322) to control the pest fading simulation unit 200 and the path loss simulation unit 300 so that the attenuation and phase characteristics of the wired link testing apparatus 120 To be the same as the attenuation and phase characteristics of the radio channel to be simulated.

The memory 630 stores DAC values of each variable element with respect to time. That is, the memory 630 corresponds to a total of 72 variable elements of the wired link testing apparatus 120 composed of the two pest fading simulation units 200 and the path loss simulation unit 300, Lt; RTI ID = 0.0 > DAC < / RTI >

FIG. 7A is a diagram illustrating an example of a pest fading characteristic to be simulated by the wired link testing apparatus 120 according to the present invention, and FIG. 7B is a graph showing an example of the path loss characteristic to be simulated by the wired link testing apparatus 120 according to the present invention. Fig.

As shown in FIG. 7A, the state change time is an example of the case where the state change time = coherence time / 70 and the state change number is 700,000 times. Here, the coherence time means "1 / (2 × maximum Doppler frequency)".

If the wired link testing apparatus 120 simulates the pest fading characteristic as shown in FIG. 7A, by operating the base station (i.e., the first base station 111 or the second base station 112) and the terminal 130 in this situation , The real-time automatic gain control function of the terminal 130 can be checked.

In this situation, the two base stations (i.e., the first base station 111 and the second base station 112) and the terminal 130 are connected to each other by the wired link testing apparatus 120, The handover function can be checked.

Here, the pest fading characteristic of FIG. 7A and the path loss characteristic of FIG. 7B are characteristics of one of a plurality of radio links constituting a radio channel.

As described above, the wired link testing apparatus 120 can simulate any radio channel without frequency selectivity. Therefore, by properly selecting the wireless channel simulated by the wired link testing apparatus 120 and operating the base stations 111 and 112 and the terminal 130 in this situation, it is possible to check the performance of the system in the room prior to the outdoor link test (See the description of Figs. 7A to 7B).

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. The present invention is not limited to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a wired link testing apparatus for checking the performance of a multi-antenna system according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a pest fading simulation unit according to an embodiment of the present invention,

3 is a configuration diagram of an embodiment of a path loss simulator according to the present invention,

4 is an exemplary diagram illustrating a power budget of the pest fading simulation unit of FIG. 2 and the path loss simulation unit of FIG. 3. FIG.

FIG. 5 is a conceptual diagram illustrating the meaning of the power budget of FIG. 4,

FIG. 6A is a configuration diagram of an embodiment of a control unit according to the present invention,

6B is a connection diagram showing a connection between the control signal of the control unit of FIG. 6A, the pest fading simulation unit and the path loss simulation unit,

FIG. 7A is a diagram illustrating an embodiment of a pest fading characteristic to be simulated by a wired link testing apparatus according to the present invention,

FIG. 7B is an exemplary view of a path loss characteristic to be simulated by a wired link testing apparatus according to an embodiment of the present invention; FIG.

DESCRIPTION OF THE REFERENCE NUMERALS

111: first base station 112: second base station

120: wired link test apparatus 130: terminal

140: external computer 200: pest fading simulator

300: path loss simulator 600:

Claims (8)

In a wired link testing apparatus, A simulating means for constructing a wired link corresponding to the wireless link for the multiple antenna system and simulating the wireless link characteristic using each variable element disposed on the wired link; And For controlling the variable element according to a predetermined value of the variable element, and a control unit for controlling the variable element according to a predetermined value of the variable element, ≪ / RTI > Wherein the simulating means comprises: Path loss simulating means for simulating a path loss characteristic to an 'RF signal transmitted by an antenna' by disposing each first variable element on a wired link; And A fast fading simulation means for constructing a wired link such that the 'RF signal transmitted by each antenna' is received by all the antennas and arranging each second variable element on the wired link to simulate fast fading characteristics Including, Wherein the path loss simulating means comprises: An uplink and downlink path loss correcting means for correcting uplink downlink attenuation so that the same attenuation can be applied to the uplink and downlink using a circulator and a fixed attenuator, And a plurality of antennas. The method according to claim 1, In the radio link characteristic, A wired link test apparatus for checking the performance of a multi-antenna system including path loss characteristics and pest fading characteristics. The method according to claim 1, The predetermined value of the variable element Wherein the wired link is a DAC (Digital Analog Converter) value of the variable element for indicating an attenuation characteristic and a phase characteristic of the wireless link. delete The method according to claim 1, The first variable element is a variable attenuator, Wherein the second variable element is a variable attenuator and a variable phase shifter. delete The method according to claim 1, Wherein the up-down path loss correcting means comprises: And transmitting the RF signal from the first and second base stations to the terminal and transmitting the RF signal from the terminal to the first and second base stations. Link test equipment. The method according to claim 1, Wherein, The wireless link characteristic may include 'a predetermined value of the variable element generated by applying a lookup table prepared from a result of measuring the wire link attenuation characteristic and the phase characteristic according to the DAC value for all the variable elements in the hardware of the wired link testing apparatus' And controls the variable element accordingly. The apparatus for testing a wired link for checking the performance of a multi-antenna system.

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