TWI647460B - Over the air measurement system for wireless communication device - Google Patents

Abstract

A wireless communication device airborne measurement system includes an anechoic chamber, a device to be tested, at least one first test antenna, and a plurality of second test antennas. The device under test has at least one antenna to be tested, and is disposed in the anechoic chamber. The first test antenna is disposed in the anechoic chamber and is at a distance from the first far field of the device to be tested. The electromagnetic wave signal emitted by the first test antenna is used to represent the line-of-sight electromagnetic wave signal provided by the wireless signal source to the device under test. The plurality of second test antennas are disposed in the anechoic chamber and are at a distance from the second far field of the device to be tested, and the second far field distance is smaller than the first far field distance, and the electromagnetic waves emitted by the plurality of second test antennas are used to represent the wireless signal source. A multipath electromagnetic wave signal supplied to the device under test. As such, measurements in the anechoic chamber can be closer to the actual application scenario.

Description

Wireless communication device air transmission measurement system

The present invention relates to a wireless communication technology, and more particularly to a wireless communication device air transmission measurement system.

The wireless communication device necessarily has an antenna and uses electromagnetic waves for information transmission. The transmission performance obtained in various practical application scenarios may be significantly different due to electromagnetic wave transmission characteristics, but based on antenna performance limitations and product development costs, it is not possible for various wireless communication devices. One-to-one measurement in actual application scenarios, over-the-air (OTA) testing in anechoic chambers is a lower-cost performance test.

Antenna tests traditionally performed in anechoic chambers use free space as a reference environment to present parameters such as radiation field, isolation, gain, and the like. Moreover, the transmission performance test for the wireless communication device in the anechoic chamber is also applicable to the ideal line-of-sight (LOS) case without reflection, and does not conform to 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 get 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, The industry still needs a lower cost and more efficient test method.

Embodiments of the present invention provide a wireless communication device air transmission measurement system, which includes an anechoic chamber, a device to be tested, at least one first test antenna, and a plurality of second test antennas. The device under test has at least one antenna to be tested, and is disposed in the anechoic chamber. The at least one first test antenna is disposed in the anechoic chamber and is at a first far field distance from the device under test, and the at least one first test antenna and the at least one antenna to be tested directly transmit electromagnetic wave signals to each other. The electromagnetic wave signal emitted by the at least one first test antenna is used to represent a line-of-sight electromagnetic wave signal supplied to the device under test by a wireless signal source. The plurality of second test antennas are disposed in the anechoic chamber and are spaced apart from the second far field of the device to be tested, wherein the second far field distance is less than the first far field distance, and the plurality of second test antennas and the device to be tested are at least The antennas to be tested directly transmit electromagnetic wave signals to each other, and the electromagnetic waves emitted by the plurality of second test antennas are used to represent the multipath electromagnetic wave signals provided by the wireless signal source to the device under test.

In summary, unlike the conventional measurement system, the wireless communication device air transmission measurement system provided by the embodiment of the present invention can measure not only the far field radiation field of the antenna of the wireless communication device but also the hardware environment. The two signals of the analog wireless communication device for the external wireless signal source (or wireless transmission object) in the actual application scenario are the antenna measurement using the first test antenna to represent the line of sight transmission, and the second test antenna representing the environmental reflection. Multipath signal measurement.

For a better understanding of the features and technical aspects of the present invention, reference should be made to the accompanying drawings The scope is subject to any restrictions.

1‧‧‧ anechoic chamber

2‧‧‧Device under test

21‧‧‧ antenna to be tested

31‧‧‧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

1 is a block diagram of an airborne transmission measurement system of a wireless communication device according to an embodiment of the present invention.

2 is a schematic view showing the configuration of an anechoic chamber according to an embodiment of the present invention.

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

Please continue to refer to FIG. 1. In terms of signal and data processing, the airborne measurement system further includes a multi-input multi-output (MIMO) network analyzer 4a, a vector network analyzer 4b, and switching control. The turntable controller 6 and the computer 7. The computer 7 is connected to the multi-input multi-output network analyzer 4a, the vector network analyzer 4b and the switching controller 5, and controls the multi-input multi-output network analyzer 4a, the vector network analyzer 4b, the switching controller 5, and the turntable control. Device 6 is used to control the measurement process and extract measurement data. The turntable 9 is connected to the turntable controller 6, and the turntable controller 6 is used to control the turntable 9 so that the device under test 2 placed on the turntable 9 can be rotated in place. The multiple input multiple output network analyzer 4a has Software-Defined Radio (SDR) and artificial intelligence algorithm to assist antenna measurement and parameter analysis, and the vector network analyzer 4b can be a generally commercially available vector network. Road analyzer. The multiple input multiple output network analyzer 4a connects the first test antenna 31, the second test antenna 32, and the antenna 21 to be tested of the device under test 2, wherein the multiple input multiple output network analyzer 4a can be connected through the channel simulator 8. The second test antenna 32 is connected to the second test antenna 32 without the need for the channel simulator 8. The channel simulator 8 has functions of phase adjustment, time delay and signal attenuation for the signal, and the channel simulator 8 can also be connected and controlled by the computer 7. The vector network analyzer 4b connects 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 multiple input multiple output 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 multiple input according to the input indication of its user interface (not shown). The phase, time delay, and signal strength of the wireless transmit signal of the multiple output network analyzer 4a. The wireless transmission signal of the multiple input multiple output network analyzer 4a is divided into an LOS signal and an MUT signal, and is supplied to the first test antenna 31 and the second test antenna 32, respectively. Furthermore, the switching controller 5 can also be connected to a commercially available multiple input multiple output base station 4c (or a wireless network access device, Access Point) to replace the multiple input multiple output network analyzer with the actual product transceiver. 4a.

Referring again to Figures 1 and 2, both the first test antenna 31 and the second test antenna 32 are arranged to be movable. The orientation of each of the second test antennas 32 relative to the device under test 2 is adjustable, and the distance between each of the second test antennas 32 and the device under test 2 is also adjustable, for example, the position of the second test antenna 32 and The distance from the device 2 to be tested is adjusted according to a predetermined channel model, and the type of the channel model used can also be changed, and the present invention is not limited. The number of the second test antennas 32 is, for example, three or more, and these second test antennas 32 surround the circumference of the device 2 to be tested. When working in the far field measurement situation, the anechoic chamber 1 must conform to the far field condition, and the first far field distance and the second far field distance must meet the far field condition, that is, the first far field distance d1 and the second far distance. The field distance d2 is greater than or equal to 2D ² /λ, where D is the largest dimension (or antenna diameter) of the antenna to be tested, and λ is the wavelength of the electromagnetic wave. In response to the measurement requirements of the fifth generation mobile communication (5G) technology products and Internet of Things (IoT) devices, there are three measurement methods: (a) Passive testing: using the vector network analyzer 4b for the first test antenna The wireless signal transmission and reception between the 31 and the antenna 21 to be tested completes the traditional antenna parameter measurement, including: Total Radiated Power (TRP), Total Isotropic Sensitivity (TIS), and equivalent Parameters such as Effective Isotropic Radiated Power (EIRP) and 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 under test 2, and the multiple input multiple output network analyzer 4a transmits and receives non-signaling wireless signals for throughput. The throughput test can also be switched to replace the operation of the multiple input multiple output network analyzer 4a with the multiple input multiple output base station 4c, and directly test with the existing product, and the device under test 2 is regarded as the terminal. Device. (c) Composite active test: including receive mode (Rx) and transmit mode (Tx), and non-signaling wireless signals for throughput testing. The receiving mode (Rx) is to simultaneously use the first test antenna 31 and the second test antenna 32 as signal transmitting ends and the antenna 21 (receiving end) to perform wireless signal transmission. The transmission mode (Tx) is such that the antenna 21 to be tested is used as a signal transmitting end to simultaneously perform wireless signal transmission on the first test antenna 31 (receiving end) and the second test antenna 32 (receiving end). Regardless of the reception mode (Rx) or the transmission mode (Tx), the first test antenna 31 and the second test antenna 32 have respective signal types. Taking the receiving mode (Rx) as an example, the first test antenna 31 is a LOS signal that is transmitted by a straight line representing a remote base station signal without reflection, and the second test antenna 32 is a signal transmitted from the remote base station to the device under test 2 The signal near and around at least one (or more) reflections is the MUT signal. The reason why the signal source represented by the test antenna is divided into two types is that, compared with the actual use environment of the wireless communication product in the application environment, the remote base station can directly transmit the signal to the device 2 to be tested, but this is established in two Under the condition that there is no barrier or obstruction between the two, and unless the device under test 2 is very close to the remote base station, in most cases, when the remote base station sends a signal toward the device 2 to be tested, there will be A part of the signal (which deducts the signal transmitted by the straight line belongs to this type) must pass at least one reflection to reach the device under test 2, so that the signal from the remote base station is distinguished into the LOS signal and the MUT signal, and the LOS The signal only accounts for a part of the total signal strength sent by the remote base station. The MUT signal is only a part of the total signal strength of the remote base station. The sum of the LOS signal and the MUT signal may be the sum of all the 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). Depending on the distance between the device 2 to be tested and the remote base station, and the obstacle environment between the two, so that the environment under which the device under test 2 can cause signal reflection, the LOS signal and the MUT signal actually reach the test. The position of the device 2 allows the signal strength, time delay and phase received by the device under test 2 to be significantly different. In an 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 is not zero, and the first test antenna 31 is issued according to the environmental reflection condition to be simulated. The signal strength ratio of both the LOS signal and the MUT signal emitted by the second test antenna 32 is adjustable, and when the intensity of the MUT signal increases, it represents an increase in the degree of environmental reflection. 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. The way in which the first test antenna represents the LOS signal and the second test antenna represents the MUT signal is to reconstruct the channel model in a space (measuring darkroom) space, which can replace the channel traditionally simulated by software algorithm. Simulator device.

In summary, unlike the conventional measurement system, the wireless communication device air transmission measurement system provided by the embodiment of the present invention can measure not only the far field radiation field of the antenna of the wireless communication device but also the hardware environment. The two signals of the analog wireless communication device for the external wireless signal source (or wireless transmission object) in the actual application scenario are the antenna measurement using the first test antenna to represent the line of sight transmission, and the second test antenna representing the environmental reflection. Multipath signal measurement.

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

Claims (8)

A wireless communication device airborne measurement system includes: an anechoic chamber; a device to be tested, having a plurality of antennas to be tested, disposed in the anechoic chamber; at least one first test antenna disposed in the anechoic chamber and at a distance The at least one first test antenna and the antennas to be tested of the device under test directly transmit electromagnetic wave signals to each other, and the electromagnetic wave signals emitted by the at least one first test antenna are used to represent a wireless signal source provides a line of sight electromagnetic wave signal to the device under test, wherein the line of sight electromagnetic wave signal is not zero; a plurality of second test antennas are disposed in the anechoic chamber and a second far field distance from the device to be tested, The second far field distance is smaller than the first far field distance, and the second test antennas and the antennas to be tested of the device to be tested directly transmit electromagnetic wave signals to each other, and the electromagnetic waves emitted by the second test antennas are used to represent The wireless signal source provides a multipath electromagnetic wave signal to the device under test, wherein the number of the second test antennas is more than three, a second test antenna is disposed around the device to be tested; a multiple input multiple output network analyzer is connected to the at least one first test antenna, the second test antennas, and the antennas to be tested of the device under test, The multiple input multiple output network analyzer has a software defined radio; a vector network analyzer connecting the at least one first test antenna and the antenna to be tested of the device under test; a switching controller connected to the Between the at least one first test antenna and the multiple input multiple output network analyzer, and connected between the at least one first test antenna and the vector network analyzer, for controlling the at least one first test antenna Switching status; a computer connecting the multiple input multiple output network analyzer, the vector network analyzer and the switching controller, controlling the multiple input multiple output network analyzer, the vector network analyzer and the switching controller, Taking measurement data, wherein the computer controls the phase, time delay and signal strength of the wireless transmission signal of the multiple input multiple output network analyzer according to an input indication of a user interface, and the wireless transmission signal is divided into the The line-of-sight electromagnetic wave signal and the multi-path electromagnetic wave signal are respectively provided to the at least one first test antenna and the second test antennas. The wireless communication device over-the-air measurement system according to claim 1, further comprising a channel simulator, wherein the multiple input multiple output network analyzer connects the second test antennas through the channel simulator. The wireless communication device airborne measurement system according to claim 1, further comprising a turntable and a turntable controller, wherein the device to be tested is disposed in the turntable in the anechoic chamber, the turntable is connected to the turntable controller, The turntable controller is connected to the computer. The wireless communication device over-the-air measurement system of claim 1, wherein the vector network analyzer is configured to measure total radiant power, total omnidirectional sensitivity, equivalent isotropic radiation power, and radiation pattern. The wireless communication device over-the-air measurement system of claim 1, wherein the multiple input multiple output network analyzer transmits and receives non-signaling wireless signals for throughput testing. The wireless communication device over-the-air measurement system of claim 1, wherein each of the second test antennas is adjustable relative to the position of the device under test, and each of the second test antennas is The distance of the measuring device is adjustable. The wireless communication device airborne measurement system according to claim 1, wherein the positions of the second test antennas and the distance from the device to be tested are based on a channel. The model is adjusted. The wireless communication device over-the-air measurement system according to claim 1, wherein the device to be tested is a notebook computer, a laptop computer, a tablet computer, an integrated computer, a smart TV, a small base station, a wireless router, or a smart type. Mobile phone.