JP2000183832A - Method for deciding parameter for radio wave environment in radio terminal test and radio terminal testing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reflect main contribution of a delay profile by selecting a ray having large power in turn to make it a reproduction parameter when a reproduction parameter in a radio wave environment is decided from a delay profile found by simulation. SOLUTION: A delay profile calculating means 11 calculates a delay profile calculated by a ray tracing method. The delay profile includes many rays. Because, generally, only a small number of rays can be reproduced by a fading simulator, several rays are selected from the delay profile. When the number of rays to be selected is defined as (n), the ray of (n) waves is selected from what is maximum in such a case to be defined as a parameter for a radio wave environment where the delay time, attenuation quantity and the Doppler frequency of each wave are reproduced. This selection is performed by a reproduction parameter deciding means 12, and an antenna driving means 20 drives each antenna TX1 to TX4 according to decision results.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio terminal test apparatus for evaluating the performance of a radio terminal by creating a radio environment equivalent to a real environment indoors and determining a reproduction parameter representing the radio environment from a delay profile obtained by simulation. The present invention relates to a method for determining a parameter of a radio wave environment in a wireless terminal test for giving an effective parameter and a wireless terminal test apparatus to which the method is applied.

[0002]

2. Description of the Related Art As a conventional radio terminal test apparatus of this type, for example, there is a radio terminal test apparatus presented at the 98th IEICE Communication Society Conference, B-1-37 shown in FIGS. The radio wave environment in the real environment is a multipath propagation environment in which a large number of radio waves arrive at a reception position with various amplitudes, delay times, polarizations, and directions. In order to reproduce this radio wave environment, a plurality of antennas Tx1 to Tx4 are installed around the wireless terminal 3 in the field simulator room 1 covered with the wall of the absorber 2 as shown in FIG. Emit radio waves equivalent to the real environment near the direction. A radio environment corresponding to the real environment including the direction of arrival of radio waves is reproduced around the wireless terminal 3.

To explain this in more detail, in the case of an example in which four antennas Tx1 to Tx4 shown in FIG. 7 are arranged, a space is divided into four in a horizontal plane, and radio waves having the radio wave environment of each area are radiated from each antenna. I do. The parameters of the radio wave environment including the directionality radiated from each antenna are measured or estimated.

A method of estimating by the ray tracing method will be described. In order to estimate a radio wave environment such as an urban area, FIG.
A three-dimensional propagation model simulating the shape of a building in an urban area as shown in FIG. Using this propagation model, simulation based on the ray tracing method is performed to estimate the radio wave environment. As shown in FIG. 9, the space around the receiving point
FIG. 10 shows an example of estimating a delay profile of a radio wave reaching each region when the image is divided. Then, radio waves having the characteristics of each area are radiated from each antenna of FIG.

[0005] However, the delay profile used to reproduce the radio wave environment in the prior art includes a large number of RAs.
Since Y is included, even if a fading simulator that can generally reproduce only a small number of RAYs is used, the delay profile cannot be completely reproduced. Therefore, the delay profile is reduced in some way by a small number of RAYs.
It was necessary to approximate with the characteristic of.

[0006]

As described above, in the conventional wireless terminal test apparatus, it was necessary to approximate the delay profile with a small number of RAY characteristics by some method. However, the reproduction parameter of the radio wave environment was obtained by simulation. There is a problem that a specific method for determining from the delay profile is not clearly defined.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem. In order to approximate a delay profile with a small number of RAY characteristics by some method, a reproduction parameter of a radio wave environment is obtained from a delay profile obtained by simulation. It is an object of the present invention to provide a method for determining a parameter of a radio wave environment in a wireless terminal test that provides a specific method for determining, and a wireless terminal test apparatus to which the method is applied.

[0008]

SUMMARY OF THE INVENTION In view of the above-mentioned object, the present invention provides a radio terminal test for reproducing a radio environment equivalent to a real environment in a field simulator room. A method for determining a parameter of a radio wave environment in a wireless terminal test is characterized in that, when determining, a parameter is selected in order from a RAY having a large power and used as a reproduction parameter.

Further, the present invention is characterized in that, when determining a reproduction parameter from the delay profile obtained by the above simulation, a time region expressing the delay profile is divided into a plurality of regions, and a RAY is selected from each region as a reproduction parameter. The method for determining a parameter of a radio wave environment in a wireless terminal test is described below.

Further, according to the present invention, when determining a reproduction parameter from the delay profile obtained by the above simulation, a time region expressing the delay profile is divided into a plurality of regions, and all the RAYs included in each region are measured from an infinite distance. Under the condition that it arrives at the receiving position with the same electric field, delay time, and direction of arrival, a large number of received powers received when the receiving position moves are represented by a cumulative probability distribution, and the median value and the rice factor are represented by reproduction parameters. A method for determining a parameter of a radio wave environment in a wireless terminal test.

Further, the present invention weights and averages the Doppler frequency and the delay time of each RAY included in each region divided into a plurality of parts by time with the power of each RAY. A method for determining a parameter of a radio wave environment in a wireless terminal test is characterized in that a Doppler frequency and a delay time of the area are used as reproduction parameters.

Further, according to the present invention, from a delay profile obtained by simulation, R
A method for determining a parameter of a radio wave environment in a wireless terminal test is characterized in that a delay profile from which AY is extracted is determined, and a reproduction parameter is determined from the delay profile.

Further, the present invention provides a field simulator room which accommodates a radio terminal and radiates radio waves from an antenna provided in the room to reproduce a radio environment equivalent to a real environment, and a simulation of radio waves arriving at the radio terminal by simulation. A control unit including a delay profile calculating unit for calculating a delay profile, and a reproduction parameter determining unit for selecting in order from the RAY having a large power among the delay profiles obtained by the delay profile calculating unit and using the RAY as a reproduction parameter of a radio wave environment; And an antenna driving unit that drives the antenna according to the reproduction parameter determined by the reproduction parameter determination unit of the control unit.

The present invention also resides in a wireless terminal test apparatus, wherein the reproduction parameter determining means divides a time region expressing a delay profile into a plurality of regions, selects a RAY from each region, and sets a RAY as a reproduction parameter.

Further, according to the present invention, in the reproduction parameter determining means, a time region expressing a delay profile is divided into a plurality of regions, and all RAYs included in each region are transmitted from infinity at the same electric field, delay time, and arrival direction. A wireless terminal characterized in that a large number of received powers received when the reception position moves are represented by a cumulative probability distribution under the condition that the reception position is reached, and a median value and a rice factor are used as reproduction parameters. In the test equipment.

Further, according to the present invention, in the reproduction parameter determining means, a time region expressing a delay profile is divided into a plurality of regions, and a Doppler frequency and a delay time of each RAY are assigned to each RAY included in each region. A wireless terminal test apparatus is characterized in that the weighted and averaged values of the RAY power are used as the Doppler frequency and delay time of the area and these are used as reproduction parameters.

Further, according to the present invention, in the reproduction parameter determining means, a delay profile in which a certain level of RAY is extracted from the maximum value is obtained from the delay profile obtained by the simulation, and the reproduction parameter determining means determines the delay profile from these delay profiles. A wireless terminal test apparatus is characterized in that a reproduction parameter is determined.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing an example of the configuration of a control section of a wireless terminal test apparatus according to the present invention. In the figure, reference numeral 10 denotes a control unit including a delay profile calculating means 11 for calculating a delay profile in accordance with, for example, an external command, and a reproduction parameter determining means 12 for determining a reproduction parameter of a radio wave environment from these delay profiles. An antenna driving unit that drives each of the antennas Tx1 to Tx4 according to the reproduction parameter obtained by the parameter determination unit 12 and emits a desired radio wave. The field simulator room provided with these antennas Tx1 to Tx4 is the same as the conventional one shown in FIG. The control unit 10 is configured by a computer that operates according to a program.

Embodiment 1 Next, an operation based on Embodiment 1 of the present invention will be described. FIG. 2 shows a calculation example of the delay profile obtained by the ray tracing method by the delay profile calculation means 11. This delay profile includes a number of RAYs. Generally, the number of RAYs that can be reproduced by the fading simulator is small, so some RAYs are selected from this delay profile. R to select
When the number of AYs is n, in the method according to this embodiment, the n-ray RAYs are selected from the largest ones, and the delay time, attenuation and Doppler frequency of each wave are to be reproduced. I do. This selection is performed by the reproduction parameter determination unit 12, and the antenna driving unit 20 drives each of the antennas Tx1 to Tx4 according to the determination result.

FIG. 3 shows an example in which n is 3. here,
The RAY represented by the solid line represents the RAY selected from the delay profiles in FIG. 2, and the RAY represented by the dotted line represents the one not selected. It can be seen that among the many RAYs included in the delay profile, three RAYs are selected from the largest ones. The number of RAYs to be selected is not limited to three, and a predetermined number of RAYs may be selected in ascending RAY order.

Embodiment 2 FIG. Next, an operation of determining a reproduction parameter according to the second embodiment of the present invention will be described. When the number of RAYs selected from the delay profile obtained by the simulation is n, the time region of the delay profile is divided into n regions, and one R
AY shall be selected. FIG. 4 shows an example where n is 3. Here, the RAY represented by the solid line represents the RAY selected from the delay profiles in FIG. 2, and the RAY represented by the dotted line represents the one not selected. It can be seen that the time domain is divided into three and one maximum RAY is selected from each time domain. This division and selection are performed by the reproduction parameter determination means 12.

Embodiment 3 FIG. Next, an operation of determining a reproduction parameter based on Embodiment 3 of the present invention will be described. Assuming that the number of RAYs selected from the delay profile obtained by the simulation is n, the time domain of the delay profile is divided into n areas, and all the RAYs included in each area have the same electric field and delay from infinity. Under the condition that the vehicle arrives at the receiving position in time and direction of arrival, a large number of received powers received when the receiving position moves are represented by a cumulative probability distribution, and the median value and the Rice factor are used as reproduction parameters.

That is, the number of RAYs existing in one area divided into n areas is m, and d is
The electric field _Σ at a remote position is given by the following equation.

[0024]

(Equation 1)

From this, it can be seen that when the receiving position d changes, _AΣ also changes.

For example, d is a step size Δx in the X direction in the XY plane.
Is moved mx times in the Y direction with a step size Δy, and _Σ is calculated mx × my times, and the received power mx × my times is represented by a cumulative probability distribution as shown in FIG. From this cumulative probability distribution, the median of the received power and the rice factor are determined. The same operation is performed on all the n time regions divided into n time regions to obtain reproduction parameters. This division and processing are performed by the reproduction parameter determination means 12.

Embodiment 4 Next, an operation of determining a reproduction parameter based on Embodiment 4 of the present invention will be described. Assuming that the number of RAYs selected from the delay profiles obtained by the simulation is n, the time region of the delay profile is divided into n regions, and each region is divided into R regions.
The Doppler frequency and delay time of AY
The values weighted and averaged by the power of Y are used as the Doppler frequency and delay time of the region, and these are used as reproduction parameters.

That is, the number of RAYs existing in one area divided into n areas is represented by m, and the Doppler frequency Dn and the delay time Tn as reproduction parameters are obtained by the following equations.

[0029]

(Equation 2)

Here, Pi, Di and Ti are each R
AY power, Doppler frequency and delay time.
The same operation is performed on all the n time regions divided into n time regions to obtain reproduction parameters. This split,
The processing is performed by the reproduction parameter determining means 12.

Embodiment 5 Next, an operation of determining a reproduction parameter based on Embodiment 5 of the present invention will be described. As shown in FIG. 6, among all the RAYs included in the delay profile obtained by the simulation, a certain level of RAY is extracted from the largest one. FIG.
In the delay profile shown in Table 2,
FIG. 6 shows an example of extracting a dB RAY. Here, the RAY indicated by the solid line represents the extracted RAY. The method of the first to fourth embodiments is applied to the delay profile shown in FIG. This processing is also performed by the reproduction parameter determining means 12.

[0032]

As described above, according to the present invention, when the reproduction parameter of the radio wave environment is determined from the delay profile obtained by the simulation, the RAY with the larger power is selected in order and used as the reproduction parameter. A method for determining a parameter of a radio wave environment in a wireless terminal test that can reflect a main contribution, and a wireless terminal test apparatus can be provided.

Further, by dividing the time region expressing the delay profile into a plurality of regions and selecting the RAY from each region and using it as a reproduction parameter, the RAY is extracted from the entire time region of the delay profile. Method of determining parameters of radio wave environment in reflected wireless terminal test,
A wireless terminal test apparatus can be provided.

Further, the time region expressing the delay profile is divided into a plurality of regions, and all the RAYs included in each region are divided.
Under the condition that it arrives at the receiving position in the same electric field, delay time, and direction of arrival from infinity, a large number of received powers received when the receiving position moves are represented by a cumulative probability distribution, and the median value and Since the Rice factor is used as a reproduction parameter, it is possible to provide a method for determining a parameter of a radio wave environment in a wireless terminal test and a wireless terminal test apparatus that can well reflect a fine contribution.

Further, the Doppler frequency and delay time of each RAY weighted by the power of each RAY and averaged for all the RAYs included in each region divided into a plurality of parts in time are obtained. In order to use Doppler frequency and delay time as reproduction parameters,
A method for determining a parameter of a radio wave environment in a wireless terminal test that can reflect an approximate Doppler frequency and a delay time, and a wireless terminal test apparatus can be provided.

From the delay profiles obtained by the simulation, a delay profile in which a certain level of RAY is extracted from the maximum value is obtained, and the reproduction parameters are determined from these delay profiles by the above-described methods. Since extraction is performed, it is possible to provide a method for determining a parameter of a radio wave environment and a wireless terminal test apparatus in a wireless terminal test that can easily evaluate the whole.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a configuration of a control portion of a wireless terminal test apparatus according to the present invention.

FIG. 2 is a diagram showing a calculation example of a delay profile according to the present invention.

FIG. 3 is a diagram for explaining determination of a reproduction parameter based on the first embodiment of the present invention.

FIG. 4 is a diagram for explaining determination of a reproduction parameter based on Embodiment 2 of the present invention.

FIG. 5 is a diagram showing an example of a cumulative probability distribution of received power based on Embodiment 3 of the present invention.

FIG. 6 is a diagram showing an example of determining reproduction parameters based on Embodiment 5 of the present invention.

FIG. 7 is a diagram showing a configuration of a field simulator room of the wireless terminal test apparatus.

FIG. 8 is a diagram showing a conventional propagation model for obtaining a delay profile.

FIG. 9 is a diagram showing a conventional definition of a space.

FIG. 10 is a diagram illustrating a calculation example of a conventional delay profile.

[Explanation of symbols]

1 field simulator room, 2 absorber, 3 wireless terminal, Tx1 to Tx4 antenna, 10 control unit, 11
Delay profile calculation means, 12 reproduction parameter determination means, 20 antenna driving unit;

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5K042 BA11 CA02 CA13 DA01 EA02 EA13 EA14 FA08 FA11 FA15 FA20 JA10 5K067 AA02 BB04 DD41 EE02 EE32 KK03 KK13 KK15 LL08

Claims (10)

[Claims] 1. In a wireless terminal test for reproducing a radio environment equivalent to a real environment in a field simulator room, when determining a reproduction parameter of a radio environment from a delay profile obtained by a simulation, RAYs having higher power are selected in order. A method for determining a parameter of a radio wave environment in a wireless terminal test, wherein the parameter is a reproduction parameter. 2. The method according to claim 1, wherein when determining a reproduction parameter from the delay profile obtained by the simulation, a time region expressing the delay profile is divided into a plurality of regions, and RAY is selected from each region to be a reproduction parameter. Item 1. A method for determining parameters of a radio wave environment in a wireless terminal test according to item 1. 3. When a reproduction parameter is determined from the delay profile obtained by the above simulation, a time region expressing the delay profile is divided into a plurality of regions, and all the RAYs included in each region have the same electric field from infinity, Under the condition that the receiver arrives at the receiving position in the delay time and the arrival direction, a large number of received powers received when the receiving position moves are represented by a cumulative probability distribution, and the median value and the rice factor are used as reproduction parameters. The method for determining a parameter of a radio wave environment in a wireless terminal test according to claim 1, wherein: 4. A method in which the Doppler frequency and delay time of each RAY that is included in each area divided into a plurality of parts in time are weighted by the power of each RAY and averaged. 2. The method according to claim 1, wherein the Doppler frequency and the delay time are used as reproduction parameters. 5. A delay profile obtained by extracting a certain level of RAY from a maximum value from delay profiles obtained by simulation, and a reproduction parameter is determined from these delay profiles.
5. The method for determining a parameter of a radio wave environment in a wireless terminal test according to any one of items 4 to 4. 6. A field simulator room for storing a wireless terminal and emitting a radio wave from an antenna provided in the room to reproduce a radio wave environment equivalent to a real environment, and a simulation of a delay profile of a radio wave arriving at the wireless terminal. A control unit including: a delay profile calculating unit to be calculated; and a reproduction parameter determining unit that selects, in order from the delay profile obtained by the delay profile calculating unit, a RAY having a higher power and sets the selected parameter as a reproduction parameter of a radio wave environment. A radio terminal test device, comprising: an antenna driving unit that drives the antenna according to the reproduction parameter determined by the reproduction parameter determination unit of the unit. 7. The reproduction parameter determining means,
7. The wireless terminal test apparatus according to claim 6, wherein a time region expressing the delay profile is divided into a plurality of regions, and a RAY is selected from each region and used as a reproduction parameter. 8. The reproduction parameter determining means,
Divide the time domain representing the delay profile into multiple
Under the condition that all RAYs included in each area arrive at the receiving position in the same electric field, delay time, and direction of arrival from infinity, the cumulative probability of the large number of received powers received when the receiving position moves is calculated. The wireless terminal test apparatus according to claim 6, wherein the wireless terminal test apparatus is represented by a distribution, and a median value and a rice factor are used as reproduction parameters. 9. The reproduction parameter determining means,
The time domain expressing the delay profile is divided into a plurality of parts, and for all the RAYs included in each area, the Doppler frequency and the delay time of each RAY are weighted by the power of each RAY and averaged. The wireless terminal test apparatus according to claim 6, wherein the Doppler frequency and the delay time are used as reproduction parameters. 10. The reproduction parameter determining means obtains a delay profile obtained by extracting a certain level of RAY from the maximum value from the delay profile obtained by the simulation, and the reproduction parameter determining means determines the reproduction parameters from these delay profiles. The wireless terminal test apparatus according to any one of claims 6 to 9, wherein the determination is performed.