TWI237462B - Multi-path simulation system and method thereof - Google Patents

Abstract

The invention provides a multi-path simulation system and method, which utilize the anechoic chamber to prevent external electromagnetic interference and prevent other uncontrollable signal transmission path generated in test and simulate the main indirect path of signal by the reflective face of the anechoic chamber. Further utilize attenuator to attenuate signal to simulate the attenuation of signal during transmission process in space. The movable table and rotary table in the anechoic chamber controlled by control unit carry dipole antenna and wireless communication device to be tested respectively. The former can change antenna position to simulate the phase difference between direct path and main indirect path of system. The latter can change the orientation of communication device to measure the air waves send/receive state of the wireless communication device to be tested.

Description

1237462 V. Description of the invention (1) [Technical field to which the invention belongs] The present invention relates to a multi-path simulation system and method, especially an anechoic chamber to avoid external electromagnetic interference, and uses the reflection surface in it to match A multipath simulation system and method for subtracting devices from analog signals in the process of inter-work transmission. [Previous Technology] In recent years, with the rapid advancement of wireless communication technology, the application of mobile phones (mobUe phone) and wireless local area networks (wireiess 1 ⑽ w wea network; WLAN) has become increasingly common. Compared with only one: the transmission of body line signals, the transmission of wireless signals has the characteristics of "path two 1. The so-called multipath refers to the characteristics of wireless signals in space M, such as walls, obstacles, etc., will cause it!" As for the gates with multiple paths between the transmitting end and the receiving end, due to the phase deviation, these signals arriving from different paths form phase shifts between each other to form interference phenomena and channel decay. Second, multiple paths, etc. Effect, increasing the homogeneity of signal production, and this multi-path effect is the overwhelming majority: Yi Er: Existing phenomenon 'However, for wireless communication equipment', such as mobile phone manufacturers: Road: Surface Card: Wireless bridge " etc. ^ σ can only be used to simulate the product in the darkroom of the radio wave. The main product is = s = received. It is completely impossible to trust the test report of the product used in the real environment. 'Therefore, there is an urgent need for a convenient and effective way to test the characteristics of its products.

Page 5 1237462 V. Description of the invention (2) No. 7 delivery-like evil in the use environment serves as an important basis for design and development. In a multi-path wireless communication environment, a direct path and many indirect paths are usually included. The direct path refers to the path from the transmitting end to the receiving end without any reflection in the middle, while the indirect path means that the signal from the transmitting end to the receiving end will be reflected by at least one j. Compared with the direct path, the indirect path will cause greater attenuation to the signal. Therefore, although there may be many different indirect paths, the one with the least attenuation of the signal is usually selected as the representative, and the others are omitted. In this specification, this representative is referred to as the primary indirect path. In conventional practice, the architecture shown in Figure j is used to simulate such a wireless communication area with a direct path and a main indirect path. The architecture of Figure 1 is placed in an open space, such as an open space outdoors. The structure includes a signal generating device U to generate a test signal; 12 a day, it is coupled to the signal generating device 丨 i to transmit a test signal; a reflection 1 3 is located behind the antenna 12 and can reflect the test signal to generate a signal The reverse signal 丨 and a device under test 14 receive a test signal and a reflection signal. Let's say, the path that directly propagates from the antenna 12 to the device under test 14 is the direct path, the main indirect path that propagates from the antenna 12 to the device under test 14 via the reflector 13. That is, however, the architecture of Figure 1 has many shortcomings, mainly two points. This architecture is placed in an open space, so it is difficult to avoid the magnetic interference (EMI) and the residual reflection path of the electrical output. Second, the position of the device under test 14 must be actually changed.

Page 6 1237462

V. Explanation of the invention (3) Adjusting the transmission distance of the signal 'operation is limited by space limitation, but lacks flexibility. In view of this, the present invention proposes a multi-path simulation system and method, which can not only avoid external electromagnetic interference and generate unnecessary reflection paths, but also is not limited by communication space in operation. [Summary of the Invention] The present invention uses an anechoic chamber (3 乜 丨 6 1 (16 (13116 to 0: ^ chamber)) to avoid external electromagnetic interference and the generation of unnecessary outdoor paths. The anechoic chamber wall is made of special materials. The signal is transmitted to the inner wall, and most of the energy is absorbed. The intensity of the reflected signal can be reduced to a minimum. This issue ^ Uses a signal to reduce the transmitted signal to reduce the transmitted signal tiger to simulate the attenuation of the signal in the external transmission process. In this way, it is possible to simulate signal transmission in various environments without being limited by the size of the anechoic chamber. As mentioned above, the main object of the present invention is to provide a multi-simulation system including at least: a signal generating device for Generating -a; an attenuation device coupled to the signal generating device for attenuating this, and generating an attenuation signal to simulate the signal attenuation in the space transmission process; and an anechoic chamber. The interior of the anechoic chamber contains : An antenna is connected to the attenuation device to transmit the attenuation signal, and a direct path and a main indirect path of the system can be simulated by adjusting the antenna position. A phase difference; a reflecting surface that can reflect the attenuation signal to generate a reflection signal; and a communication device for receiving the attenuation signal and the reflection signal. A second object of the present invention is to provide a multi-path simulation method, which at least includes ·· Generate a signal; attenuate this signal and generate an attenuated signal

1237462 V. Description of Invention (4) to simulate the attenuation of this signal during the space transfer process; use an antenna to transmit the attenuation signal, where the antenna is located in an anechoic chamber with a reflecting surface, and this reflecting surface can reflect the attenuation The signal generates a reflected signal; and a communication device in the anechoic chamber is used to receive the attenuated signal and the reflected signal. The invention uses a anechoic chamber to isolate external electromagnetic interference and absorb reflected signals, and uses an attenuation device to simulate the attenuation in the signal transmission process, and uses a reflector to simulate the main indirect path to achieve the simulation of real radio wave space and control this. The purpose of the radio wave space is to make various radio experiments or measurements through the quasi-real radio wave space that can be controlled to obtain the evaluation results close to the real use environment. Therefore, another object of the present invention is to provide a method for measuring the diversity gain of a communication device. The communication device has a switchable between an early antenna mode and an antenna diversity mode, and is placed in an anechoic chamber. This method includes the following steps: a. Set the communication device to a single antenna mode; b. Generate a test signal; c. Attenuate the test signal by one attenuated amplitude; d. Use an antenna in an anechoic chamber to transmit attenuation The next test signal, in which the anechoic chamber has a reflecting surface, which can reflect the attenuated test signal to generate a reflected signal; e • the communication device receives the attenuated test signal and reflected signal; f • measures one of the signals received by the communication device Parameters to obtain a reference value; g · switch the communication device to antenna diversity mode and repeat steps b to e; h · adjust the attenuation range of the test signal to obtain the second attenuation range so that the signal parameters received by the communication device Equal to the reference value; and i. Calculate the difference between the first and second attenuation amplitudes, which is the antenna diversity gain of the communication device .

1237462 V. Description of the invention (5) In order to allow your reviewers to further understand and agree with the present invention, the embodiments of the present invention are described in detail below with reference to the drawings. [Embodiment] In this section, specific embodiments will be used to describe in detail the implementation of the multi-path simulation system and method of the present invention, and an application example of the present invention, that is, the measurement of the diversity gain of a wireless communication device. Figure 2 is a block diagram of a preferred embodiment of the multi-path simulation system of the present invention. As mentioned above, the multi-path simulation system of the present invention is used to simulate a wireless communication space with direct traffic and main indirect paths. As shown in FIG. 2, the multi-path simulation system 20 includes: a signal generating device 21 for generating a -signal; and an attenuation device 22 coupled to the signal generating device = 21 'for attenuating the signal to generate an attenuation A signal; a control unit 23, coupled to the signal generator 21 and the attenuation device 22, for controlling the attenuation amplitude of the signal generator and the attenuation device 22; and-radio wave dark: 24: to isolate the evening: electromagnetic Reflection effects when interference is propagating. ^

The inside of the anechoic chamber 24 contains a dipole antenna 241, which is coupled to the attenuation filter 90 L. It can be adjusted in the anechoic 4 "to launch the ^ path and the main indirect path Phase between phases = position 'analog face 2 g direct face reflecto) 242, J; ^:-^^ (S〇Ud) Among them, the dipole antenna 241 is a commonly used 2 subtraction signal and reflection signal. Ο Used in books Antenna with a 360 ° transmitter

Page 9 (6) V. Description of the invention To 1 is suitable for the use of the present invention. The reflecting surface 242 is represented by a thin line, which is constructed of the same material as the other inner walls of the anechoic chamber 24 (represented by a thick line). Referring to FIG. As a starting point, via the attenuation device 22, enter the anechoic chamber 2 4 ^ j and then directly transmit to the communication device 243 via the dipole antenna 241 without reflection. As for the main indirect path, it is different from the aforementioned direct path. Second, after the signal is transmitted by the dipole antenna 241, it is reflected (the dipole antenna 241 is located between the reflective surface 242 and the communication body = 242), and then propagates to Communication device 243. In order to obtain a better simulation effect for the simulation system 20, the signal generating device 21 is a selected sample of the communication device 243 (Golden Magic, and its characteristics are far in line with the technical standards to be followed by the communication device 243). And specifications, so the quality of the generated signal is better and meets the test requirements. In addition, a t = = 5 Tigers 4 (VeCtοr Slgnal generator) can be used as the signal generating device 2i, if necessary, with a power amplifier (Mpower amplifier). Can produce more accurate and diverse signals as required. In addition, the attenuation device 22 may be a step attenuator whose attenuation amplitude is adjusted in a stepwise manner by the control unit, so that the signal generated by the analog signal generating device 21 is attenuated during the transmission process in the wireless communication space. Generally, the larger the attenuation, the longer the & meter signal transmission distance. The anechoic chamber 24 may further include-to change the communication device 2 4 3 receiving turntable 244, which can bear the position of the communication device (Λζ 丨 mu t). By 243 1237462 V. Invention Description (8) — --- Set the characteristics of the signal received by 243. The signal characteristics here may include signal strength, signal quality, frame error rate (rror rate), and lean flow rate (Throughput). With the control unit 23, in addition to controlling the signal generation and adjusting the attenuation range of the signal, the turntable 244 can be controlled to measure the field shape of the antenna, and the platform 245 can be used to simulate the phase difference between the direct path and the indirect path, and obtain The characteristic of the received signal 'is subjected to subsequent analysis steps.

Next, it is explained how to use the aforementioned simulation system 20 to implement the multi-path simulation method of the present invention. Fig. 3 is an operation flowchart of the preferred embodiment of the multi-path simulation method of the present invention. As shown in FIG. 3, the method includes the following steps: 3 1 signal generating device 21 generates a signal; 3 2 reducing device 2 2 reduces the signal and generates an attenuated signal to simulate the signal during space transmission Attenuation; 33 dipole antenna 241 transmits an attenuation signal, and the reflection surface 242 reflects the attenuation signal to generate a reflection signal; and 34 communication device 243 receives the attenuation signal and the reflection signal. In step 33, the position of the dipole antenna 241 can also be adjusted by the control unit 23 to change the distance between the direct path of the analog system 20 and the main indirect path.

Phase difference (that is, the phase difference between the attenuated signal and the reflected signal received by the communication device 243). In step 34, the rotation angle of the turntable 244 can also be adjusted by the control unit 23 to change the orientation of the signal received by the communication device 243. By using the multi-path simulation system 20 of the present invention, wireless communication devices can be performed.

Page 12 1237462 V. Description of the invention (9) Testing of various signal reception. The method for measuring the diversity gain of a wireless communication device using the analog system 20 will be discussed below. Here, the communication device 2 4 3 ′ in the simulation system 20 is a communication device with a switchable single antenna mode and antenna diversity mode. Fig. 4 is a flow chart for measuring the antenna diversity gain using the multipath simulation system 20 'of the present invention. As shown in Figure 4, this flow includes the following steps: 41 the control unit 23 sets the communication device to a single antenna mode; 4 2 the signal generating device 21 generates a test signal; 43 the attenuation device 22 attenuates the test signal first Attenuation amplitude; 44 dipole antenna 241 emits the attenuated test signal, and a reflective signal is reflected by the reflecting surface 242 attenuated test signal; 45 the communication device receives the attenuated test signal and reflected signal; 4 6 control unit 2 3 Measure the signal parameters received by the communication device to get a reference value. 47 Control unit 23 switches the communication device to antenna diversity mode and repeats steps 4 2 to 4 5; 48 Attenuation device 22 attenuates the test signal by a second attenuation amplitude , So that the signal parameter received by the communication device is equal to the reference value; and the 49 control single W3 calculates the difference between the first and second attenuation amplitudes, which is the diversity gain of the chaos device. Using the control unit 23 to adjust the position of the dipole antenna 241 can change the phase of the fade. ° Between the direct transmission path and the main indirect transmission path of the flood type ^ ^ Repeat steps 41 to 49 for different phase differences. Effect of signal phase difference on diversity gain.

1237462 V. Description of the invention (10) Similarly, using the control unit 23 to adjust the rotation angle of the turntable 244 can change the orientation of the signal received by the communication device. Repeat steps 41 to 49 for different directions to know the reception of the communication device. The effect of bearing on diversity. The signal described in W can refer to other parameters (such as RSQ I) or data flow. The above description uses the preferred embodiments to make the present invention in detail, and not to limit the target range of w + ~ Ming. Anyone who is familiar with the modification of this technique is especially good. The talents of the artisans are all in favor of / :: The patent application scope of the patent application can be guaranteed 1, 2 times, the present invention each-> Q, border. 2. The patent requirements stated above are shown in the i 1 g & t quotation method. Regulations and grant quasi-patents as

Page 14 1237462 Schematic description Figure 1 is a schematic diagram of a conventional multi-path simulation system. Fig. 2 is a block diagram of a preferred embodiment of the multi-path simulation system of the present invention. Fig. 3 is an operation flowchart of the preferred embodiment of the multi-path simulation method of the present invention. Fig. 4 is a flowchart illustrating the operation flowchart of the antenna diversity gain measurement using the multi-path simulation system of the present invention: 1 2-antenna 14-device under test 2 1-signal generating device 2 3-control unit 2 4 1 _ Dipole antenna 243-Communication device 245-Mobile platform 11-Signal generation device 1 3-Reflector 2 0-Multipath simulation system 2 2-Attenuation device 2 4-Anechoic chamber 2 4 2-Reflective surface 244-Turntable 246- Silence zone 3b 3 4-Operation flow of the multipath simulation method of the present invention 4b 4 9-Operation flow of using the multipath simulation system of the present invention to measure antenna diversity gain

Page 15

Claims (1)

1237462 6. Scope of patent application 1. A multi-path simulation system including at least: a signal generating device for generating a signal; an attenuation device coupled to the signal generating device for attenuating the signal to generate an attenuation signal To simulate the attenuation of the signal during space transmission; and a shielded anechoic chamber, which contains: an antenna coupled to the attenuation device to transmit the attenuation signal, and the adjustment can be performed by adjusting the The position of the antenna simulates the phase difference between a direct path of the system and a main indirect path; and a reflecting surface can reflect the attenuated signal to generate a reflected signal. 2. The multi-path simulation system according to item 1 of the scope of patent application, wherein the interior of the anechoic chamber further comprises: a communication device for receiving the attenuation signal and the reflection signal. 3. The multi-path simulation system according to item 1 of the scope of patent application, wherein the signal generating device is a vector signal generator. 4. The multi-path simulation system according to item 2 in the scope of patent application, wherein the signal generating device is a selected sample of the communication device (Golderi Sample). The path simulation system, wherein the attenuation device is a step attenuator. 6. The multi-path simulation system according to item 1 of the scope of patent application, wherein the antenna is a dipole antenna. 7. The multi-path simulation system according to item 2 of the scope of patent application, wherein Page 16 1237462 6. Scope of patent application The antenna is located between the reflecting surface and the communication device. 8. The multi-path simulation system according to item 1 of the scope of patent application, further comprising: a control unit coupled to the signal generating device and the attenuation device, for controlling the generation of the signal, and adjusting the attenuation device. Attenuation amplitude. 9 The multi-path simulation system as described in item 2 of the scope of patent application, further comprising a control unit coupled to the communication device to obtain the characteristics of the signal received by the communication device. 10. The multi-path simulation system according to item 2 of the scope of patent application, wherein the anechoic chamber further comprises: a turntable capable of carrying the communication device to change the position of the signal received by the communication device. 11. The multi-path simulation system according to item 1 of the scope of patent application, wherein the anechoic chamber further comprises: a mobile platform that can carry the antenna to adjust the position of the antenna. 1 2. The multi-path simulation system according to item 2 of the scope of patent application, wherein the communication device is located in a quiet zone of the radio wave anechoic chamber. 1 3. A multi-path simulation method, including at least: generating a signal; attenuating the signal and generating an attenuation signal to simulate the attenuation of the signal during space transmission; Page 17 1237462 6. The scope of the patent application uses an antenna to transmit the attenuation signal, wherein the antenna is located in an anechoic chamber with a reflecting surface, and the reflecting surface can reflect the attenuation signal to generate a reflection signal; and using the radio wave A communication device in the dark room receives the attenuation signal and the reflection signal. 14. The multi-path simulation method as described in item 13 of the scope of patent application, wherein the signal is generated using a vector signal generator. 15. The multi-path simulation method as described in item 13 of the scope of patent application, wherein the signal is generated using a selected sample of the communication device. 16. The multi-path simulation method as described in item 13 of the scope of patent application, wherein the signal is attenuated by a step attenuator. 1 7. The multiple path simulation method as described in item 13 of the scope of patent application, wherein the antenna is located between the reflecting surface and the communication device. 1 8. The multiple path simulation method described in item 13 of the scope of patent application, further comprising: adjusting the position of the antenna to simulate a phase difference between a direct path and a main indirect path of the system. 19. The multi-path simulation method according to item 13 of the scope of patent application, wherein the communication device is placed on a turntable, and the method further includes adjusting the rotation angle of the turntable to change the orientation of the signal received by the communication device. . 20. The multi-path simulation method as described in item 13 of the scope of patent application, wherein the communication device is located in a quiet zone of the anechoic chamber. 2 1. —A method for measuring the diversity gain of a communication device, the communication device Page 18