TW201947236A - Over the air measurement system for wireless communication device - Google Patents

Abstract

An OTA measurement system for wireless communication device comprises an anechoic chamber, a device under test (DUT), at least a first test antenna, and a plurality of second test antennas. The DUT in the anechoic chamber has at least an antenna under test (AUT). The first test antenna disposed in the anechoic chamber keeps a first far-field distance with the DUT. The electromagnetic wave signal from the first test antenna represents a line-of-sight (LOS) signal for the DUT from a wireless signal source. The plurality of second test antennas disposed in the anechoic chamber keeps a second far-field distance with the DUT. The second far-field distance is shorter than the first far-field distance. The electromagnetic wave signals from the plurality of second test antennas represent multi-path signals for the DUT from the wireless signal source. Thus, the OTA test can be more close to real application scenarios.

Description

   Wireless communication device air transmission measurement system   

The present invention relates to a wireless communication technology, and in particular, to an air transmission measurement system for a wireless communication device.

Wireless communication devices must have antennas and use electromagnetic waves for information transmission. The transmission efficiency obtained in various practical application scenarios will be significantly different due to the characteristics of electromagnetic wave transmission. However, based on antenna performance limitations and product development costs, it cannot be used for various wireless communication devices. Measure one by one in actual application scenarios, and perform the Over The Air (OTA) test in an anechoic chamber is a lower cost performance test method.

Traditionally, antenna tests in anechoic chambers use free space as a reference environment to present parameters such as radiation field pattern, isolation, gain, and so on. In addition, the transmission performance test of the wireless communication device in the anechoic chamber is only applicable to the ideal line of sight (LOS) without reflection, which does not meet the multi-path effect of the real application environment. The actual performance of the product is often different from the laboratory test of the product. If you need to obtain performance test results that are closer to the real application conditions, you need to test in the real field space, but because the cost is too high, Industry still needs lower cost and more efficient testing methods.

An embodiment of the present invention provides an air transmission measurement system for a wireless communication device. The air transmission measurement system includes an anechoic chamber, a device under test, at least one first test antenna, and a plurality of second test antennas. The device to be tested has at least one antenna to be tested, and is arranged in an anechoic chamber. The at least one first test antenna is disposed in an anechoic chamber with a first far-field distance from the device under test, and the at least one first test antenna and at least one antenna under test of the device under test directly transmit electromagnetic wave signals to each other, the The electromagnetic wave signal emitted by the at least one first test antenna is used to represent a line-of-sight electromagnetic wave signal provided by a wireless signal source to the device under test. The plurality of second test antennas are disposed in the dark room of the radio wave and are at a second far-field distance from the device under test, the second far-field distance is less than the first far-field distance, and the plurality of second test antennas and at least the device under test An antenna under test directly transmits electromagnetic wave signals to each other, and the electromagnetic waves emitted by the plurality of second test antennas are used to represent multi-path electromagnetic wave signals provided by the wireless signal source to the device under test.

In summary, unlike the traditional measurement system, the wireless communication device air transmission measurement system provided by the embodiment of the present invention can not only measure the far-field radiation pattern of the antenna of the wireless communication device, but also the hardware environment. The two types of signals used by the simulated wireless communication device for external wireless signal sources (or wireless transmission objects) in actual application scenarios are the antenna measurement using the first test antenna to represent the line of sight, and the second test antenna to represent the reflection through the environment. Multipath signal measurement.

In order to further understand the features and technical contents of the present invention, please refer to the following detailed description and accompanying drawings of the present invention, but these descriptions and attached drawings are only used to illustrate the present invention, not the rights to the present invention. No limitation on scope.

1‧‧‧ Anechoic Chamber

2‧‧‧device under test

21‧‧‧Antenna to be tested

31‧‧‧The first test antenna

32‧‧‧Second Test Antenna

4a‧‧‧Multiple Input Multiple Output Network Analyzer

4b‧‧‧ Vector Network Analyzer

4c‧‧‧Multiple Input Multiple Output Base Station

5‧‧‧Switch controller

6‧‧‧ Turntable Controller

7‧‧‧ computer

8‧‧‧ Channel Simulator

9‧‧‧ turntable

FIG. 1 is an architecture diagram of an air transmission measurement system for a wireless communication device according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of an anechoic chamber provided by an embodiment of the present invention.

The wireless communication device air transmission measurement system according to the embodiment of the present invention is used to measure the wireless transmission performance of the device under test. The device under test is, for example, a notebook computer, a laptop computer, a tablet computer, an integrated computer, a smart TV, and a small base station. , Wireless router, or smartphone. Please refer to FIG. 1 and FIG. 2. FIG. 1 is a structural diagram of an air transmission measurement system of a wireless communication device according to an embodiment of the present invention, and FIG. 2 is a schematic diagram of a configuration of an anechoic chamber provided by an embodiment of the present invention. This wireless communication device airborne measurement system includes an anechoic chamber 1, a device under test 2, at least one first test antenna 31, and a plurality of second test antennas 32. The device under test 2 (which may be generally referred to as a DUT) has at least one antenna 21 to be tested, and is disposed in the anechoic chamber 1, such as a turntable 9 disposed in the anechoic chamber 1. The at least one first test antenna 31 is disposed in the anechoic chamber 1 and at a first far-field distance d1 from the device 2 to be tested. The first test antenna 31 and the antenna 31 to be tested 2 directly transmit electromagnetic wave signals to each other. The electromagnetic wave signal emitted by the first test antenna 31 is used to represent a line of sight signal (LOS signal) provided by a wireless signal source to the device under test 2 (hereinafter referred to as a LOS signal). The number of antennas to be tested 21 may be plural, and the number of the first test antennas 31 may also be plural. Furthermore, a plurality of second test antennas 32 are arranged in the anechoic chamber 1 and are at a second far-field distance d2 from the device 2 to be measured, the second far-field distance d2 is smaller than the first far-field distance d1, and the plurality of first The two test antennas 32 and the DUT 21 of the DUT 2 directly transmit electromagnetic wave signals to each other. The electromagnetic waves emitted by the plurality of second test antennas 32 are used to represent the multi-path electromagnetic wave signals provided by the wireless signal source to the DUT 2. (multi-path signal), hereinafter referred to as MUT signal.

Please continue to refer to FIG. 1. In terms of signal and data processing, this air transmission measurement system further includes a multi-input multi-output (MIMO) network analyzer 4a, a vector network analyzer 4b, and a switching control. Device 5, turntable controller 6, and computer 7. The computer 7 is connected to the MIMO network analyzer 4a, the vector network analyzer 4b and the switching controller 5, and controls the MIMO network analyzer 4a, the vector network analyzer 4b, the switching controller 5 and the turntable control. The device 6 is used for controlling the measurement process and acquiring measurement data. The turntable 9 is connected to a turntable controller 6, and the turntable controller 6 is used to control the turntable 9 so that the device 2 to be tested placed on the turntable 9 can be rotated in place. Multiple input multiple output network analyzer 4a has Software-Defined Radio (SDR) and artificial intelligence algorithms to assist antenna measurement and parameter analysis, and the vector network analyzer 4b can be a general commercially available vector network Road Analyzer. The MIMO network analyzer 4a is connected to the first test antenna 31, the second test antenna 32 and the antenna 21 of the device 2 to be tested. The MIMO network analyzer 4a can be connected to the first through the channel simulator 8. The second test antenna 32 is directly connected to the second test antenna 32 without the channel simulator 8. The channel simulator 8 has functions such as phase adjustment, time delay and signal attenuation of the signal. The channel simulator 8 can also be connected and controlled by the computer 7. The vector network analyzer 4b is connected to the first test antenna 31 and the antenna 21 to be tested. The switching controller 5 is connected between the first test antenna 31 and the MIMO network analyzer 4a, and is connected between the first test antenna 31 and the vector network analyzer 4b, and is controlled by the computer 7 to control The switching condition of the first test antenna 31. The computer 7 controls the phase, time delay, and signal strength of the wireless transmission signal of the multiple-input, multiple-output network analyzer 4a according to input instructions from its user interface (not shown). The wireless transmission signals of the MIMO network analyzer 4a are divided into LOS signals and MUT signals, and are provided to the first test antenna 31 and the second test antenna 32, respectively. In addition, the switching controller 5 can also be connected to a commercially available multiple-input multiple-output base station 4c (or wireless network access point, Access Point), and replace the multiple-input multiple-output network analyzer with a transceiver of an actual product. 4a.

Referring again to FIGS. 1 and 2, the first test antenna 31 and the second test antenna 32 are both movable. The orientation of each second test antenna 32 relative to the device under test 2 is adjustable, and the distance between each second test antenna 32 and the device under test 2 is also adjustable, such as the position of the second test antenna 32 and The distance from the device under test 2 is adjusted according to a previously determined channel model, and the type of the channel model used can also be changed, which is not limited in the present invention. The number of the second test antennas 32 is, for example, three or more. These second test antennas 32 surround the periphery of the device 2 to be tested. When working in the far-field measurement, the anechoic chamber 1 must meet the far-field conditions. The above-mentioned first and second far-field distances must meet the far-field conditions, that is, the first far-field distance d1 and the second far-field distance. The field distance d2 is greater than or equal to 2D ² / λ, where D is the largest size (or antenna diameter) of the antenna under test, and λ is the wavelength of the electromagnetic wave. In response to the measurement needs of products of the fifth generation mobile communication (5G) technology and the Internet of Things (IoT) devices, it can be divided into three measurement methods: (a) Passive test: The vector network analyzer 4b is responsible for the first test antenna Wireless signal transmission and reception between 31 and antenna 21 to be tested, complete the traditional antenna parameter measurement, including: Total Radiated Power (TRP), Total Isotropic Sensitivity (TIS), Equivalent Total Parameters such as Effective Isotropic Radiated Power (EIRP) and Radiation Pattern (Radiation Pattern). (b) General active test: the first test antenna 31 is used to communicate with the antenna 21 to be tested of the device 2 to be tested, and the multiple-input multiple-output network analyzer 4a sends and receives non-signaling wireless signals for throughput Throughput testing can also be switched to use the multiple-input multiple-output base station 4c instead of the multiple-input multiple-output network analyzer 4a to test directly with existing products. At this time, the device under test 2 is regarded as a terminal. Device. (c) Composite active test: including receiving mode (Rx) and transmission mode (Tx), and using non-signaling wireless signals for throughput testing. In the receiving mode (Rx), the first test antenna 31 and the second test antenna 32 are used as signal transmitting ends and the test antenna 21 (receiving end) is used for wireless signal transmission. In the transmission mode (Tx), the antenna 21 to be tested is used as a signal transmitting end and wireless signal transmission is performed to the first test antenna 31 (receiving end) and the second test antenna 32 (receiving end) at the same time. Regardless of the reception mode (Rx) or the transmission mode (Tx), the first test antenna 31 and the second test antenna 32 have their respective signal types. Taking the receiving mode (Rx) as an example, the first test antenna 31 represents the LOS signal transmitted in a straight line without the reflection of the signal from the remote base station, and the second test antenna 32 represents the signal from the remote base station to the device under test 2 The signals around and after at least one (or more) reflections are MUT signals. The reason that the signal source represented by the test antenna is divided into two types is that compared to the actual use of wireless communication products in the application environment, the remote base station can directly send signals to the device under test 2, but this is based on the two Under the condition of no barriers or obstacles between the users, and unless the device under test 2 is very close to the remote base station, in most cases the remote base station will send a signal in the direction of the device under test 2 Part of the signals (the signals that have passed through the straight line are all of this type) must reach at least one reflection after at least one reflection. It can be seen that the signals from the remote base station are distinguished into LOS signals and MUT signals, and LOS The signal only accounts for a part of the total signal strength sent by the remote base station, and the MUT signal also accounts for only a part of the total signal strength sent by the remote base station. The sum of the LOS signal and the MUT signal may be the sum of all signals sent by the remote base station Or less than the sum of all signals sent by the remote base station (some signals cannot reach the device under test 2). According to the distance between the device under test 2 and the remote base station, and the obstacle environment between the two, so that the environment around the device under test 2 that can cause signal reflection, the LOS signal and the MUT signal actually reach the test target. The location of the device 2 makes the signal strength, time delay and phase of the device 2 under test significantly different. In an exemplary case, when the channel model is to represent that there is no obstacle between the device under test 2 and the remote base station, the LOS signal is not zero, and according to the environmental reflection situation to be simulated, the first test antenna 31 sends The ratio of the signal strength of the LOS signal to the MUT signal sent by the second test antenna 32 is adjustable. When the strength of the MUT signal increases, it means that the degree of environmental reflection increases. In another exemplary case, when the channel model is to represent an obstacle between the device under test 2 and the remote base station, the LOS signal may be zero, and only the MUT signal. This method of using the first test antenna to represent the LOS signal and the second test antenna to represent the MUT signal is to reconstruct the channel model in hardware (in the darkroom) by using hardware, which can replace the channel traditionally simulated by software algorithms. Simulator device.

In summary, unlike the traditional measurement system, the wireless communication device air transmission measurement system provided by the embodiment of the present invention can not only measure the far-field radiation pattern of the antenna of the wireless communication device, but also the hardware environment. The two types of signals used by the simulated wireless communication device for external wireless signal sources (or wireless transmission objects) in actual application scenarios are the antenna measurement using the first test antenna to represent the line of sight, and the second test antenna to represent the reflection through the environment. Multipath signal measurement.

The above description is only an embodiment of the present invention, and is not intended to limit the patent scope of the present invention.

Claims (10)

    An air transmission measurement system for a wireless communication device includes: an anechoic chamber; an apparatus to be tested, which has at least one antenna to be tested, and is arranged in the anechoic chamber; and at least one first test antenna, which is arranged in the anechoic chamber, and is at a distance. The device under test has a first far-field distance, the at least one first test antenna and the at least one antenna under test of the device under test directly transmit electromagnetic wave signals to each other, and the electromagnetic wave signal emitted by the at least one first test antenna is used for A line-of-sight electromagnetic wave signal provided by a wireless signal source to the device under test; and a plurality of second test antennas, which are disposed in the anechoic chamber and a second far-field distance from the device under test, the second far-field distance Less than the first far-field distance, the second test antennas and the at least one antenna under test of the device under test directly transmit electromagnetic wave signals to each other, and the electromagnetic waves emitted by the second test antennas are provided on behalf of the wireless signal source. A multi-path electromagnetic wave signal to the device under test.         According to the wireless communication device over-the-air measurement system according to claim 1, wherein the number of the second test antennas is three or more, and the second test antennas surround the periphery of the device under test.         The wireless communication device air transmission measurement system according to claim 1, further comprising: a multiple-input multiple-output network analyzer connected to the at least one first test antenna, the second test antennas, and the standby The at least one antenna under test of the device under test, the multiple input multiple output network analyzer having a software defined radio; a vector network analyzer connecting the at least one first test antenna and the at least one device under test of the device under test A test antenna; a switching controller connected between the at least one first test antenna and the MIMO network analyzer, and connected between the at least one first test antenna and the vector network analyzer, Used to control the switching status of the at least one first test antenna; and a computer connected to the MIMO network analyzer, the vector network analyzer and the switching controller to control the MIMO network analysis Meter, the vector network analyzer, and the switching controller for capturing measurement data, wherein the computer controls the multi-pointer according to an input instruction of a user interface. The phase, time delay, and signal strength of the wireless transmission signal of the input multiple-output network analyzer are distinguished into the line-of-sight electromagnetic signal and the multiple-path electromagnetic wave signal, and are respectively provided to the at least one first test antenna and The second test antennas.         According to the wireless communication device over-the-air measurement system according to item 3 of the claim, it further includes a channel simulator, and the MIMO network analyzer is connected to the second test antennas through the channel simulator.         According to the wireless communication device air transmission measurement system described in the third item of the request, the wireless communication device further includes a turntable and a turntable controller. The device to be tested is disposed on the turntable in the anechoic chamber, and the turntable is connected to the turntable controller. The turntable controller is connected to the computer.         The wireless transmission device air transmission measurement system according to claim 1, wherein the vector network analyzer is used to measure total radiated power, total omnidirectional sensitivity, equivalent omnidirectional radiated power, and radiated field pattern.         The wireless communication device air transmission measurement system according to claim 1, wherein the MIMO network analyzer sends and receives non-signaling wireless signals for throughput testing.         According to the wireless communication device air transmission measurement system according to claim 1, wherein the position of each of the second test antennas relative to the device under test is adjustable, and each of the second test antenna and the device under test are adjustable. The distance of the measuring device is adjustable.         According to the wireless communication device air transmission measurement system according to claim 1, wherein the positions of the second test antennas and the distance from the device under test are adjusted according to a channel model.         The wireless communication device air transmission measurement system according to item 1 of the claim, wherein the device under test is a laptop, a laptop, a tablet, an all-in-one computer, a smart TV, a small base station, a wireless router, or a smart Mobile phone.