Patent Description:
With the rise of the Internet of Things, evermore systems are provided with wireless connectivity for communication with other systems. For this purpose, the systems are provided with radio devices, sometimes more than one radio device. The radio devices have to be robust against interference, especially from interference of signals dedicated for the other radio device of the system.

<CIT> discloses a mobile device with multiple communication modules and a software-based method for mitigating interference between the communication modules.

<CIT> shows a system for OTA tests of a device under test having a communication antenna and an interference antenna, each being mounted on a separate positioner.

<CIT> discloses a test chamber for testing devices having an interference source coupled to the chamber by an interference antenna.

<CIT> shows a test system for OTA tests of a device under test having a plurality of antennas, all of which being controlled by a single communication controller.

An example of such a system may be a vehicle with an entertainment system having a cellular radio device and a Wi-Fi radio device.

The radio devices have to be thoroughly tested, for example by over the air proximity tests to reproduce real world scenarios. Proximity tests are sometimes also called proximity coexistence tests.

However, as the dimensions of these systems are very large, such tests are difficult to carry out.

Thus, it is the object of the invention to provide a measurement setup as well as a method for performing over the air proximity tests in a simple and cost-efficient manner.

For this purpose, a measurement setup according to claim <NUM> is provided.

By providing a communication tester for a communication link and an interference antenna emitting an interference signal, the robustness of the radio device of the device under test may easily be tested under real world conditions. Further, antenna characteristics may be eliminated from the measurement.

The interference signal generator may be a vector signal generator.

For example, the quality of the communication link comprises information about the throughput, the block error rate (BLER), the bit error rate (BER) and/or the packet error rate (PER) of the communication link. Thus, easily accessible measures for the quality may be used.

In an aspect, the at least one interference signal and the communication link are statistically independent, are uncorrelated, use different channels and/or are of a different communication standard, allowing a clear distinction between the communication link and interference.

Use of a standard implies the use of the protocol specified in the respective standard. The communication link and/or the interference signal may be a signal according to the Bluetooth, LTE, <NUM> or Wifi standard.

In an embodiment of the invention, the measurement system comprises at least one first interference antenna and at least one second interference antenna, wherein the at least one first interference antenna is located at a first interference position with respect to the system under test and the at least one second interference antenna is positioned at a second interference position with respect to the system under test, particularly wherein the first interference position and/or the second interference position is in a range of up to <NUM>, in particular up to <NUM> away from the system under test. Hence, complex scenarios may be tested.

For reducing equipment costs, the first interference antenna and the second interference antenna may be selectively connected to the interference signal generator via an antenna switch unit of the measurement system.

The measurement system may comprises two interference signal generators connected to the first interference antenna and the second interference antenna, respectively, in order to model a real world scenario precisely.

In an embodiment, the system under test comprises a second radio device supporting a second communication standard, particularly wherein the interference signal is a signal according to the second communication standard, allowing very realistic testing.

The communication link may be cellular, i.e. using the LTE or <NUM> standard, and the interference signal may be a WIFI signal. For example, the second radio device is a WIFI Access point.

In order to reduce manufacturing costs, the first radio device and the second radio device are integrated on the same chip of the system under test.

In an embodiment of the invention, the system under test comprises a vehicle, particularly wherein the at least one first interference antenna, the at least one second interference antenna and/or the communication antenna are located inside the vehicle. This way, communication robustness of vehicle systems may be assessed.

In order to create a test environment resembling a situation in traffic, the first interference antenna and/or the second interference antenna is positioned in a range of about one or several lane width and/or of about one or several vehicle dimensions away from the system under test.

The lane width may be the lane width of a highway, e.g. between <NUM> and <NUM> meters.

Further, for above purpose a method according to claim <NUM> is provided.

The features and advantages discussed in the context of the measurement system and the measurement setup also apply to the method and vice versa.

For a very precise assessment of the blocking level, the method may have the following steps:.

The interference power is, for example, the total power of the interference signals.

In a variant, the interference antenna is located at a first interference position for a first phase of the method and the interference antenna is located at a second interference position for a second phase of the method. This way, the hardware costs are reduced.

In order to allow a quick and reliable measurement, the system under test, in particular the vehicle, is rotated relative to the communication antenna using a rotation mechanism, in particular a turntable.

Further features and advantages will be apparent from the following description as well as the accompanying drawings, to which reference is made. In the drawings:.

<FIG> shows very schematically a measurement setup <NUM> comprising a system under test <NUM> (SUT) and a measurement system <NUM>.

In the shown embodiment, the system under test <NUM> is a vehicle <NUM>, for example a passenger car. Of course, the system under test <NUM> may also be any other system like a refrigerator, a wagon of a train, or the like.

The system under test <NUM>, e.g. the vehicle <NUM> comprises a communication and entertainment system <NUM> having a first radio device <NUM> and a second radio device <NUM>, as well as a passenger cabin <NUM>.

The first radio device <NUM> is configured to communicate using a first communication standard, and the second radio device <NUM> is configured to communicate using a second communication standard.

The first communication standard and the second communication standard may be the same standard or different standards. The first communication standard and the second communication standard may be chosen from a Bluetooth, LTE, <NUM> and Wi-Fi standard.

The first radio device <NUM> and the second radio device <NUM> may be integrated on the same chip of the entertainment system <NUM> of the vehicle <NUM>.

For example, the first radio device <NUM> is a cellular user equipment, e.g. supporting the LTE and/or <NUM> communication standard, and the second radio device <NUM> is a Wi-Fi access point supporting the Wi-Fi standard.

The measurement system <NUM> comprises a communication tester <NUM>, a first interference signal generator <NUM> with an associated first interference antenna <NUM>, a second interference signal generator <NUM> and an associated second interference antenna <NUM>, a control unit <NUM> and a rotation mechanism <NUM>, for example a turntable.

Optionally, the measurement system <NUM> may comprise a receive antenna <NUM> connected to a signal analyzer <NUM>.

The communication tester <NUM> comprises a signal generator <NUM> and a communication antenna <NUM>. The communication signal generator <NUM> may be a vector signal generator.

The control unit <NUM> controls and is connected to - especially via a cable-bound connection - the first interference signal generator <NUM>, the second interference signal generator <NUM> and the communication signal generator <NUM>. Further, the control unit <NUM> may be connected to the signal analyzer <NUM>.

Of course, the control unit <NUM> is also connected to the rotation mechanism <NUM> to control the movement of the rotation mechanism <NUM>.

For measuring the system under test <NUM>, the system under test <NUM> is placed on the rotation mechanism <NUM> and the first interference antenna <NUM>, the second interference antenna <NUM>, the communication antenna <NUM> and the optional receive antenna <NUM> are located outside and/or inside (of the system under test <NUM>), e.g. inside the passenger cabin <NUM> of the vehicle <NUM>.

The communication antenna <NUM> is placed at a communication position PC and directed towards the system under test <NUM>, the first interference antenna <NUM> is placed at a first interference location PI1, the second interference antenna <NUM> is located at a second interference position PI2 and the optional receive antenna <NUM> is placed at a received position PR.

All of the antennas <NUM>, <NUM>, <NUM>, <NUM> are directed towards the system under test <NUM>.

The resulting situation can be seen in <FIG> schematically.

In the shown first embodiment, all of the antenna positions PC, PI1, PI2, PR are located outside the system under test <NUM>. For example, the first and the second interference position PI1, PI2 are positioned in a range of up to <NUM>, in particular up to <NUM> away from the rotation mechanism <NUM> and thus the system under test <NUM>.

Alternatively, the first and the second interference positions PI1, PI2 may be located at a distance away from the rotation mechanism <NUM> and the system under test <NUM> corresponding to about one or more widths of a lane of a highway and/or one or more dimensions of a vehicle.

For example, a lane width of a highway is between about <NUM> and <NUM>.

Measurement setups in which the distance between the interference positions PI1, PI2 is in a range of a lane width and/or a vehicle dimension, represent situations, in which the vehicle <NUM> drives on a highway with other cars surrounding the vehicle <NUM>.

For performing an over the air proximity test of the system under test <NUM>, the method shown in <FIG> is carried out.

In a first step S1, a communication link c is established over the air between the communication tester <NUM> and the first radio device <NUM> over the air.

The communication link c is continuous and held stable by the communication tester <NUM>.

For this purpose, the communication signal generator <NUM> generates a communication signal with a predefined signal power and the communication signal is emitted using the communication antenna <NUM>.

In step S2, the relative position of the system under test <NUM>, more precisely the position of the first radio device <NUM> and the communication antenna <NUM> is adjusted to receive the optimum coupling. This is done by rotating the system under test <NUM> on the rotating mechanism <NUM> and evaluating the quality of the communication link, for example by measuring the throughput, the block error rate (BLER), the bit error rate (BER) and/or the packet error rate (PER) of the communication link. The communication tester <NUM> and/or the control unit <NUM> are configured to evaluate the quality of the communication link c.

The optimization is done by rotating the system under test <NUM> until a maximum of the quality of the communication link c is obtained. This situation can be, for example, seen in <FIG>, where the system under test <NUM>, i.e. the vehicle <NUM>, has been rotated with respect to the measurement system <NUM>.

The adjustment of the relative position may also be performed with a test signal before the communication link has been established in step S1.

In the next step S3, the power of the communication signal is reduced until a predefined deterioration, for example <NUM> % loss of throughput, is achieved.

The value of the power of the communication signal leading to the predefined deterioration is recorded as the value of the reduced power by the control unit <NUM> or the radio communication tester <NUM> (step S4).

In the next step, the power of the communication signal is then increased to a testing power, in particular to the full power that may also be the same power that has been used during the adjustment of the relative position (step S5).

Subsequently in step S6, interference signals SI are generated by the interference signal generators <NUM>, <NUM> and emitted by the respective interference antennas <NUM>, <NUM>.

The interference signals SI are for example signals of the second communication standard used by the second radio device <NUM>. It is also possible, that the interference signals SI simulate or establish a communication link with the second radio device <NUM>.

The signal power of the interference signals SI depends upon the position, namely the incident angle, of the beam of the interference antenna <NUM>, <NUM>, also called interference antenna beam of the interference antenna <NUM>, <NUM>, to the system under test <NUM>.

The interference signals SI and the communication link C are uncorrelated and statistically independent. If the interference signals SI and the communication link make use of the same communication standard, i.e. the same communication protocol, different channels may be used. It is also possible, that the communication link C and the interference signal SI are of different communication standards.

The control unit <NUM> and/or the radio communication tester <NUM> evaluate the quality of the communication link C, in particular continuously (step S7).

In step S8, the power of the interference signal SI, for example the total power of all of the interference signals emitted by the interference antennas <NUM>, <NUM>, is increased until the quality of the communication link C has deteriorated to the predefined deterioration. The predefined deterioration is the same predefined deterioration that has been used to determine the reduced power in steps S3, S4. The value of the power of the interference signals SI at the occurrence of the predefined deterioration is recorded.

In the next step S9, the control unit <NUM> and/or the radio communication tester <NUM> determine a blocking level, i.e. a measure for the interference caused by the interference signals SI, based on the value of the reduced power recorded in step S4 and the value of the interference power recorded at step S8. The blocking level may be, in a simple case, the difference between the value of the reduced power and the value of the interference power.

In order to determine more complex blocking levels, also the position and alignment of the communication antenna <NUM> and/or the position and alignment of the interference antennas <NUM>, <NUM> may be used to determine the blocking level.

During the test, the receive antenna <NUM> may receive spurious emissions from the system under test <NUM> that may be analyzed using the signal analyzer <NUM>.

In this way, a quick and reliable way of determining the robustness of the first radio device <NUM> against interference, especially interference of signals for the second radio device <NUM>, can be effectively determined.

A second embodiment of the measurement setup <NUM> and the method are shown in <FIG>. The second embodiment corresponds essentially to the first embodiment so that only the differences are explained in the following. Same and functionally the same components and steps are referred to with the same reference numbers.

<FIG> show the measurement setup <NUM> during two different phases of the test of the system under test <NUM>.

In the second embodiment, the measurement system <NUM> comprises only the first interference signal generator <NUM> and the first interference antenna <NUM>.

In the second embodiment of the method, steps S1 to S5 are carried out as explained for the first embodiment.

However, the steps S6, S7 and S8 are carried out repeatedly, wherein each iteration of the set of steps S6, S7 and S8 is called a phase in the following.

A flow-chart of a method of the second embodiment is shown in <FIG>.

In the first phase, i.e. the first iteration of steps S6, S7 and S8, the first interference antenna <NUM> is located at the first interference position PI1 (<FIG>). With this arrangement, the first phase, i.e. the steps S6, S7, S8 are carried out as described for the first embodiment.

After step S8 has been completed, i.e. after the first phase, the first interference antenna <NUM> is moved to the second interference position PI2 (step SM).

With the first interference antenna <NUM> at the second interference position PI2, the second phase is carried out, i.e. steps S6 to S8 are performed again (<FIG>).

After the second phase, i.e. the second iteration of step S8, the blocking level is determined using all of the recorded values of the interference powers during the phases (step S9).

It is of course possible that more than two phases are carried out so that more than two interference positions may be used.

In the second embodiment, the quantity of equipment needed can be reduced compared to the first embodiment.

<FIG> shows a third embodiment of the measurement setup <NUM> being essentially the same as the measurement setup <NUM> of the first embodiment so that only the differences are explained in the following. Same and functionally the same parts or steps are referred to with the same reference numerals.

In the third embodiment, the first interference antenna <NUM> and the communication antenna <NUM> are located inside the system under test <NUM>. In the shown embodiment, the first interference antenna <NUM> and the communication antenna <NUM> are located inside the vehicle <NUM>, for example inside the passenger cabin <NUM>.

Another difference to the first embodiment lies in the fact that only the first interference signal generator <NUM> is provided. The first interference antenna <NUM> and the second interference antenna <NUM> are connected to the first interference signal generator <NUM> via an antenna switch unit <NUM> of the measurement system <NUM>.

The antenna switch unit <NUM> and the first interference signal generator <NUM> may be controlled in a way that the first interference antenna <NUM> and the second interference antenna <NUM> are fed in very short intervals so that both antennas <NUM> and <NUM> emit interference signals SI virtually simultaneously.

In this case, the method according to the first embodiment (<FIG>) may be carried out.

It is however possible, that the antenna control unit <NUM> and the first interference signal generator <NUM> are controlled so that either the first interference antenna <NUM> or the second interference antenna <NUM> emits an interference signal SI.

In this case, the method according to the second embodiment (<FIG>) may be carried out, wherein one of the interference antennas <NUM>, <NUM> is fed with the signal during the first phase and the other is fed with the interference signal during the second phase. The step SM of moving the antenna <NUM> is then replaced by switching of the antenna switch unit <NUM>.

With any of the measurement setups <NUM> of the three embodiments, various real world scenarios may be tested.

For example, with a measurement setup <NUM> according to the first embodiment, a situation of a vehicle <NUM> driving on a highway with various other vehicles surrounding may be simulated. In this case, the communication link C may be a cellular communication link using the LTE or <NUM> standard and the interference antennas <NUM>, <NUM> are placed at a distance to the vehicle simulating a traffic situation. For example, the interference antennas <NUM>, <NUM> are within a range of the width of one or two highway lanes or within one of several vehicle dimensions. The interference signals SI may be of the Wi-Fi or Bluetooth standard simulating hotspots of other vehicles.

In a different scenario, that may be simulated with the measurement setup <NUM> according to the second embodiment, the interference of a Wi-Fi hotspot provided by the entertainment system <NUM> of the vehicle <NUM> is tested. In this case, the communication link C may be of the Wi-Fi standard and also the interference signal SI of the first interference antenna <NUM> within the vehicle <NUM> may also be of the Wi-Fi standard simulating a second device within the vehicle <NUM>.

Of course, the interference signal SI of the first interference antenna <NUM> may be of a cellular standard, like LTE or <NUM>, simulating a mobile device within the vehicle <NUM>.

The interference signal SI emitted by the second interference antenna <NUM> outside of the vehicle <NUM> may be a cellular signal, i.e. LTE or <NUM>, simulating a cellular base station.

Of course, the shown embodiments are not limited to the number of interference antennas or interference signal generators present in the shown examples. Of course, more interference antennas and more signal generators may be used. Likewise, the antennas <NUM>, <NUM>, <NUM> may be placed inside or outside the system under test <NUM> depending on the scenario to be tested.

Claim 1:
Measurement setup for testing a system under test (<NUM>), in particular for over the air proximity tests, having a system under test (<NUM>) and a measurement system (<NUM>) for testing the system under test (<NUM>), in particular for over the air proximity tests,
wherein the system under test (<NUM>) comprises at least one first radio device (<NUM>) supporting a first communication standard,
the measurement system (<NUM>) comprising:
a communication tester (<NUM>) with a communication antenna (<NUM>) for establishing a communication link (C) over the air with the first radio device (<NUM>) of the system under test (<NUM>), wherein the communication tester (<NUM>) and the first radio device (<NUM>) are connected over the air using a communication link (C) of the first communication standard
at least one interference signal generator (<NUM>, <NUM>) configured to generate at least one interference signal (SI) interfering with the communication link (C) established by the communication tester (<NUM>), wherein the at least one interference signal (SI) and the communication link (C) are independent from one another, and
at least one interference antenna (<NUM>, <NUM>) connected to the interference signal generator (<NUM>) for emitting the interference signal (SI), wherein the at least one interference antenna (<NUM>, <NUM>) is located at at least one interference position (PI1, PI2) with respect to the system under test (<NUM>),
wherein the communication tester (<NUM>) is configured to evaluate the quality of the communication link (C),
characterized in that at least one interference signal generator (<NUM>, <NUM>) is configured for controlling the interference signal power emitted from the at least one interference antenna (<NUM>, <NUM>) depending on an incident angle of an interference antenna beam of the interference antenna (<NUM>, <NUM>) with respect to the system under test (<NUM>).