JP2010217062A - System for evaluating antenna characteristics - Google Patents

Abstract

Efficient antenna characteristic evaluation is performed with a small number of devices.
Evaluation antennas 24a and 24b are arranged in an anechoic chamber 20. It is an antenna to be evaluated. The transmission antennas 23-1 to 23-4 are antennas that are arranged in the anechoic chamber 20 and radiate radio waves to the evaluation antennas 24a and 24b. When the data sequence is divided into fixed processing units, the synthesized signal generation unit 10 groups the data sequences into an arbitrary number of processing units, and multiplies the data sequences by a code sequence that gives a desired correlation. Thus, a plurality of synthesized signals are generated. The up-converters 22-1 to 22-4 up-convert the frequency of the synthesized signal. The evaluation unit 30 down-converts radio waves received by the evaluation antennas 24a and 24b, converts the radio waves into baseband signals, and analyzes antenna characteristics.
[Selection] Figure 1

Description

  The present invention relates to an antenna characteristic evaluation system for evaluating antenna characteristics.

  An antenna is one of the key components that influence radio transmission characteristics, and a high-performance antenna is required to realize high-quality wireless communication. For this reason, antenna design that optimizes the radiation and absorption characteristics of radio waves is performed according to the radio wave propagation environment. For optimization design, antenna characteristic evaluation technology for measuring and evaluating antenna characteristics is important.

  On the other hand, in the field of wireless communication in recent years, high-speed wireless communication using the MIMO (Multi Input Multi Output: wireless communication technology for transmitting and receiving data using a plurality of antennas) method has been developed. Even in small devices such as those, it is predicted that the mounting of a multi-antenna will be essential.

  FIG. 19 is a diagram for explaining a radiation pattern of a multi-antenna. The communication terminal MS is provided with multiple antennas A1 and A2. In the multi-antenna technique, the reception state is made different between the antennas A1 and A2, and even when it is difficult to receive with the antenna on one side, the diversity reception is made possible to receive with the antenna on the other side, thereby improving the communication quality.

  As the reception states of the antennas A1 and A2 are different, the effect of diversity reception increases. For example, as shown in FIG. 19, the directivity of the antenna A1, which is one of the antennas, radiates radio waves strongly in the left direction (in the left direction). If the radiation pattern is p1, such as radiating power weakly radiated in the right direction (radiating power is weak in the right direction), the other antenna radiates the radio wave weakly in the left direction. An antenna A2 having directivity that forms a radiation pattern p2 that radiates radio waves strongly in the right direction is disposed at a position where the radiation patterns do not overlap.

  Here, consider a case where radio waves are transmitted from the left to the right and arrive at the communication terminal MS. Since the strength of the radio wave radiation pattern is the same as the strength of the radio wave absorption pattern, it is difficult for the antenna A2 to receive the incoming radio wave (the incoming radio wave b1) because the absorbed power is weak in the antenna A2. Then, since the absorbed power is strong, reception is possible.

  Further, if the communication terminal MS moves and the radio wave is transmitted from the right to the left direction and arrives at the communication terminal MS at the moving point, the antenna is applied to the incoming radio wave (referred to as the incoming radio wave b2). In A1, it is difficult to receive the signal because the absorbed power is weak. However, the antenna A2 can receive the signal because the absorbed power is strong.

  Thus, when designing a multi-antenna, in a radio wave propagation environment, the directivities of the antennas A1 and A2 are complemented with each other so that the reception state correlation between the antennas (inter-antenna correlation) becomes small. Optimize radiation (absorption) pattern.

  FIG. 20 is a diagram showing the radio wave reception intensity when the correlation between the antennas is small. The vertical axis represents radio wave reception intensity, and the horizontal axis represents time. The reception intensity when the incoming radio waves b1 and b2 are received by the antennas A1 and A2 shown in FIG.

  When there is an incoming radio wave b1 at time t0 to t1, the reception intensity of the antenna A2 decreases, but the reception intensity of the antenna A1 increases. Further, when there is an incoming radio wave b2 after time t1, the reception intensity of the antenna A1 decreases, but the reception intensity of the antenna A2 increases. In this way, the correlation between the antennas can be reduced, and the deterioration of the reception intensity can be compensated between the antennas.

  FIG. 21 is a diagram showing the radio wave reception intensity when the correlation between antennas is large. The vertical axis represents radio wave reception intensity, and the horizontal axis represents time. It is assumed that the antenna A2-1 having the same radiation pattern as the antenna A1 shown in FIG. 19 is installed in the communication terminal MSa.

  When there is an incoming radio wave b1 at time t0 to t1, the reception intensity of both antennas A1 and A2-1 increases. However, when there is an incoming radio wave b2 after time t1, the reception intensity of both antennas A1 and A2-1. Will fall. As described above, when the correlation between the antennas is large, the reception strength of both the antennas A1 and A2-1 deteriorates in the portion where the radiation pattern falls.

  When antenna optimization design is performed, antenna characteristics are evaluated. At this time, particularly when evaluating the characteristics of the multi-antenna, not only the characteristics of the single antenna but also the correlation between the antennas is an important evaluation index when determining the antenna characteristics as described above. Inter-antenna correlation is also an important factor in determining wireless characteristics such as error rate (BLER) and throughput.

  On the other hand, in an actual radio wave propagation environment, the carrier wave (carrier) transmitted from the base station is a communication terminal via multipath (a phenomenon in which signal waves propagate through multiple paths due to reflections from mountains, buildings, etc.). To reach. Therefore, when the communication terminal is moving, the Doppler shift with a different carrier frequency depends on the arrival angle of the carrier in each path (a new Doppler frequency is added to the carrier frequency, and the reception frequency is displaced). Will do).

  For this reason, the communication terminal receives a plurality of signals spread in the frequency domain, thereby fading that the level fluctuates drastically (a phenomenon in which the strength of the radio wave level changes due to interference of the wavelengths of radio waves that arrive with a time difference or The fluctuation wave). The reception level fluctuation due to fading causes an increase in BLER of information transmission in wireless communication.

  Therefore, in order to accurately evaluate the correlation between antennas, it is necessary to reproduce a fading environment simulating an actual radio wave propagation environment by computer simulation or the like. The antenna quality can be improved by statistically processing the values measured in this fading environment and realizing the optimization design.

  FIG. 22 is a diagram showing a state in which conventional antenna characteristic evaluation is performed. Signal generation sources 5-1 to 5-5 are arranged around the communication terminal MS. Each of the signal generation sources 5-1 to 5-5 generates a sine wave having a frequency shifted from the carrier frequency by different Doppler frequencies Δf1 to Δf5. In addition, each sine wave radio wave is radiated from the signal generation sources 5-1 to 5-5 in a state of an elementary wave (a single signal wave in which a plurality of signal waves are not combined).

  In the evaluation environment shown in FIG. 22, radio waves shifted from different Doppler frequencies are radiated from a plurality of signal generation sources 5-1 to 5-5 arranged around the communication terminal MS to synthesize the radio waves. Then, the communication terminal MS receives the combined wave, thereby generating a simulated fading environment.

  Here, the definition of the Doppler frequency will be described. FIG. 23 is a diagram for explaining the Doppler frequency. Consider a case where the carrier frequency fc that arrives from one path in the multipath arrives at an angle θ with respect to the traveling direction of the communication terminal MS.

  If the moving speed of the communication terminal MS is v, the wavelength of the carrier is λ, and the arrival angle is θ, the Doppler frequency Δf can be expressed by the following equation according to the apparent wavelength of the radio wave when the traveling direction is a reference.

Δf = v / (λ / cos θ) = v cos θ / λ (4)
FIG. 24 is a diagram illustrating a change in Doppler frequency according to the traveling direction of the communication terminal MS and the arrival angle of radio waves. (A) shows a case where radio waves are received from a path in the same direction as the traveling direction of the communication terminal MS, and (B) shows a case where radio waves are received from a direction perpendicular to the traveling direction of the communication terminal MS.

When a radio wave is received from a path in the same direction as the traveling direction of the communication terminal MS as shown in (A), θ = 0 and π are obtained, and the absolute value | Δf | of the Doppler frequency is maximized from the equation (4).
Further, as shown in (B), when receiving radio waves from the direction perpendicular to the traveling direction of the communication terminal MS, the apparent wavelength of the radio waves with respect to the traveling direction is not generated, and therefore the communication terminal MS is not moving. This is the same and is not affected by the Doppler shift (θ = π / 2, 3π / 2, and Δf = 0).

  Here, assuming that the communication terminal MS moves in a certain direction in the evaluation environment shown in FIG. 22, the signal generation sources 5-1 to 5-5 have the arrival angle of the radio wave with respect to the movement direction of the communication terminal MS. A corresponding Doppler frequency is set, and radio waves having the Doppler frequency are radiated.

  For example, as shown in FIG. 22, assuming that the communication terminal MS moves in the direction of the signal generation source 5-4 indicated by the arrow X, the frequency settings of the signal generation sources 5-1 to 5-5 can be obtained from Equation (4). As can be seen, the Doppler frequency Δf4 of the signal generation source 5-4 is set to be the highest, and the Doppler frequencies from the other signal generation sources are set to be lower than the Doppler frequency Δf4.

  The communication terminal MS is fixed and is not actually moved. Instead, a change in the Doppler frequency that changes along the moving direction of the communication terminal MS is caused on the signal generation sources 5-1 to 5-5 side. It is set to be variable, and the set radio wave is emitted.

  In this way, a Doppler shift when the communication terminal MS is considered to have moved is generated on the signal generation source side, and a drop in received intensity or the like occurring at the evaluation antenna at this time is measured and evaluated.

As a conventional technique for evaluating antenna characteristics, a technique has been proposed in which a plurality of scatterer antennas are arranged and the antenna characteristics are evaluated by controlling the amplitude and phase of radio waves.
In addition, a technique has been proposed in which a fading environment is simulated by moving a reflector and a scatterer around a terminal and controlling the amplitude, phase, and the like of radio waves.

  Further, a technique has been proposed in which a plurality of antennas are arranged around a terminal, and radio waves radiated from the antenna are controlled so as to have real environment characteristics in the direction of each antenna viewed from the terminal.

Japanese Patent Laying-Open No. 2005-227213 (paragraph number [0031], FIG. 1) JP 07-162376 (paragraph numbers [0045], [0046], FIG. 1) Japanese Patent Laid-Open No. 11-340930 (paragraph numbers [0024] to [0031], FIG. 1)

  When the evaluation environment as shown in FIG. 22 is realized by a specific system, normally, a measurement environment in which a plurality of antennas are arranged in an anechoic chamber is constructed, and antenna characteristics are evaluated in the anechoic chamber. An anechoic chamber is a room in which a radio wave absorber is attached to the entire surface of the indoor ceiling, wall, and floor to suppress reflection of radio waves in the room.

  FIG. 25 is a diagram showing a configuration of a conventional antenna characteristic evaluation system. The antenna characteristic evaluation system 5a includes an anechoic chamber 50, a baseband signal generation unit 51, upconverters 52-1 to 52-4, transmission antennas 53a to 53d, evaluation antennas 54a and 54b, an antenna characteristic evaluation board 55, and an evaluation terminal 56. (Hereinafter, an antenna that radiates radio waves for evaluation is referred to as a transmission antenna, and an antenna to be evaluated is referred to as an evaluation antenna.

  In the anechoic chamber 50, transmission antennas 53a to 53d for transmitting radio waves and evaluation antennas 54a and 54b to be evaluated are arranged. Transmission antennas 53a to 53d are connected to each of up-converters 52-1 to 52-4, and up-converters 52-1 to 52-4 are connected to baseband signal generation unit 51. The evaluation antennas 54 a and 54 b are connected to the antenna characteristic evaluation board 55, and the antenna characteristic evaluation board 55 is connected to the evaluation terminal 56.

  The baseband signal generation unit 51 generates a baseband signal. The up-converters 52-1 to 52-4 up-convert the baseband signal into a frequency band of an RF (Radio Frequency) signal.

  The up-converter 52-1 up-converts the baseband signal into an RF signal having a frequency shifted by a Doppler frequency Δf1 with respect to the carrier frequency. The up-converter 52-2 up-converts the baseband signal into an RF signal having a Doppler frequency of Δf2.

  The up-converter 52-3 up-converts the baseband signal into an RF signal having a Doppler frequency of Δf3. The up-converter 52-4 up-converts the baseband signal into an RF signal having a Doppler frequency of Δf4.

  The transmission antenna 53a radiates radio waves having a frequency shifted by the Doppler frequency Δf1 with respect to the carrier frequency up-converted by the up-converter 52-1. The transmitting antenna 53b radiates a radio wave whose Doppler frequency is Δf2 up-converted by the up-converter 52-2.

  The transmitting antenna 53c radiates a radio wave whose Doppler frequency is Δf3 up-converted by the up-converter 52-3. The transmitting antenna 53d radiates a radio wave whose Doppler frequency is Δf4 up-converted by the up-converter 52-4.

  The evaluation antennas 54a and 54b receive the transmitted radio waves. The antenna characteristic evaluation board 55 down-converts the radio waves received by the evaluation antennas 54a and 54b and converts them into baseband signals. Evaluation terminal 56 analyzes antenna characteristics based on the baseband signal after down-conversion.

  FIG. 26 is a diagram showing a configuration of a conventional antenna characteristic evaluation system. The antenna characteristic evaluation system 5b includes a combined signal generator 57 provided between the baseband signal generator 51 and the up-converters 52-1 to 52-4 shown in FIG. The same.

  The synthesized signal generator 57 generates a plurality of sine waves having different frequencies, and multiplies and synthesizes the baseband signal output from the baseband signal generator 51 and the sine wave to generate a plurality of synthesized signals. (A simulated multipath fading environment is generated by a plurality of synthesized signals given desired correlation).

  The up-converters 52-1 to 52-4 up-convert the combined signal output from the combined signal generation unit 57 into the frequency band of the RF signal (the subsequent operation is the same, and the description is omitted).

  Here, in the antenna characteristic evaluation system 5a shown in FIG. 25, when the multipath environment is reproduced and the antenna characteristic is evaluated with the correlation between the multipaths set to a desired value, the number of signal generation sources and transmission antennas is increased. Will increase.

  On the other hand, in the antenna characteristic evaluation system 5b shown in FIG. 26, the composite signal generator 57 as described above is provided to generate multipath fading without increasing the number of signal generation sources and transmission antennas. It becomes possible to do.

  However, the conventional antenna characteristic evaluation system 5b shown in FIG. 26 includes a baseband signal generation unit 51 that generates a baseband signal, and a combined signal generation unit 57 that processes the baseband signal and generates a combined signal. It is necessary to have two building blocks. For this reason, there existed a problem that the apparatus scale increased and the evaluation system became complicated.

  In the baseband signal generation unit 51, for example, in the case of a wireless system such as LTE (Long Term Evolution: a standard for high-speed communication service related to mobile communication such as a mobile phone), the cycle of the encoding unit (1 subframe = 1 ms) is increased. It becomes a signal, and this is stored in a memory to generate a repetitive signal.

  On the other hand, the synthesized signal generator 57 requires a signal of about several tens of Hz (for example, a signal of several tens of ms) corresponding to the Doppler shift assuming the movement of the communication terminal MS. That is, in order to evaluate the correlation between antennas simulating a multipath environment, a signal having a long period (a period of several tens of ms) is generated based on a baseband signal in order to obtain a desired correlation. There was a need (in order to arbitrarily set the correlation of a plurality of signals flowing through the propagation path, a signal that can obtain a desired correlation in several tens of ms to several seconds was generated). For this reason, the synthesized signal generation unit 57 requires an operation different from that of the baseband signal generation unit 51 that generates a signal of 1 ms period.

  As described above, since the baseband signal generation unit 51 and the synthesized signal generation unit 57 perform control with different time scales, they are conventionally provided as separate constituent blocks, and thus the evaluation system has a large scale. It was.

When evaluating antenna characteristics, it is often performed in a limited space. Therefore, it is desired to construct a system capable of evaluating antenna characteristics with a small configuration and high accuracy.
The present invention has been made in view of the above points, and an object of the present invention is to provide an antenna characteristic evaluation system that efficiently performs antenna characteristic evaluation with a small number of devices.

  In order to solve the above problems, an antenna characteristic evaluation system is provided. This antenna characteristic evaluation system generates an evaluation antenna that is an antenna to be evaluated, a plurality of transmission antennas that radiate radio waves to the evaluation antenna, and a data series that is a baseband signal, and generates a composite signal from the data series A synthesized signal generating unit that connects to the transmitting antenna, up-converts the frequency of the synthesized signal to the frequency of the radio wave, and is connected to the evaluation antenna, and the evaluation antenna when the radio wave is received. An evaluation unit for evaluating the antenna characteristics.

  Here, when the synthesized signal generation unit divides the data series into fixed processing units, the combined data series is grouped into an arbitrary number of processing units, and a code sequence that gives a desired correlation to the group of data series Is combined to generate a combined signal generating process for generating a plurality of combined signals.

  Evaluate antenna characteristics efficiently by reducing the device scale.

It is a figure which shows the structural example of an antenna characteristic evaluation system. It is a figure which shows the propagation path fluctuation | variation of a radio signal. It is a figure which shows the structure of a communication system. It is a figure which shows an example of a correlation setting. It is a figure which shows an example of a correlation setting. It is a figure which shows an example of a correlation setting. It is a figure for demonstrating a Walsh code | symbol. It is a figure which shows the block structure which produces | generates a synthetic signal. It is a figure which shows the block structure which produces | generates a synthetic signal. It is a figure which shows the block structure which produces | generates a synthetic signal. It is a figure which shows the structural example of an antenna characteristic evaluation system. It is a figure which shows the structure of a synthetic | combination signal production | generation part. It is a figure which shows the orthogonal code sequence generate | occur | produced in an orthogonal code sequence generation part. It is a figure which shows the orthogonal code sequence generate | occur | produced in an orthogonal code sequence generation part. It is a figure which shows an example of a matrix calculation. It is a figure which shows an example of a multiplication process. It is a figure which shows the structure of a synthetic | combination process part and an output process part. It is a figure for demonstrating a modification. It is a figure for demonstrating the radiation pattern of a multi-antenna. It is a figure which shows the radio wave receiving intensity when the correlation between antennas is small. It is a figure which shows the radio wave reception intensity | strength when the correlation between antennas is large. It is a figure which shows a mode when performing conventional antenna characteristic evaluation. It is a figure for demonstrating a Doppler frequency. It is a figure which shows the change of the Doppler frequency according to the advancing direction of a communication terminal, and the arrival angle of an electromagnetic wave. (A) shows a case where radio waves are received from a path in the same direction with respect to the traveling direction of the communication terminal, and (B) shows a case where radio waves are received from a direction perpendicular to the traveling direction of the communication terminal. It is a figure which shows the structure of the conventional antenna characteristic evaluation system. It is a figure which shows the structure of the conventional antenna characteristic evaluation system.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating a configuration example of an antenna characteristic evaluation system. The antenna characteristic evaluation system 1 includes transmission antennas 23-1 to 23-4, evaluation antennas 24 a and 24 b, a combined signal generation unit 10, up-converters 22-1 to 22-4, and an evaluation unit 30. This is a system for evaluating antenna characteristics (in the example shown in the figure, four transmitting antennas and two evaluation antennas are arranged in the anechoic chamber 20, but the number of these antennas is arbitrary).

  The evaluation antennas 24a and 24b are arranged in the anechoic chamber 20 and are antennas for antenna characteristic evaluation. The transmission antennas 23-1 to 23-4 are antennas as virtual scatterers that radiate radio waves to the evaluation antennas 24 a and 24 b, and are distributed at appropriate positions in the anechoic chamber 20.

  The combined signal generation unit 10 generates a data series that is a baseband signal, and generates combined signals v1 to v4 from the data series. Upconverters 22-1 to 22-4 (in general terms, upconverter 22) are connected to transmitting antennas 23-1 to 23-4, respectively, and upconvert each frequency of combined signals v1 to v4 to the frequency of the radio wave. To do.

  That is, the combined signals v1 to v4 are radiated through the transmitting antennas 23-1 to 23-4 as radio waves having Doppler frequencies Δf1 to Δf4 determined from the moving speed, moving direction, and radio wave arrival direction of the mobile device.

  The evaluation unit 30 includes an antenna characteristic evaluation board 31 and an evaluation terminal 32. The antenna characteristic evaluation board 31 is connected to the evaluation antennas 24a and 24b. The antenna characteristic evaluation board 31 down-converts the radio waves received by the evaluation antennas 24a and 24b and converts them into baseband signals. The evaluation terminal 32 analyzes antenna characteristics based on the baseband signal after down-conversion.

  Here, the combined signal generation unit 10 is a code that, when dividing a data series into a certain processing unit, makes the data series into one unit by an arbitrary number of processing units and gives a desired correlation to the unit of the data series. A composite signal generation process for generating a plurality of composite signals by multiplying the series is performed.

  Specifically, with respect to a data sequence composed of coding units (subframes), the data sequence is grouped into one unit by an arbitrary number of coding units, and desired correlation is given to the group of the data sequence. Multiplying the code sequence (setting the desired correlation) to generate a plurality of combined signals to generate fading. The detailed configuration and operation of the combined signal generation unit 10 will be described later.

  Next, the reason why the device scale of the antenna characteristic evaluation system 1 can be simplified as compared with the conventional configuration will be described. FIG. 2 is a diagram showing propagation path fluctuations of radio signals. The vertical axis represents radio wave intensity, and the horizontal axis represents time.

  As an environment for wireless communication, it is said that a Rayleigh fading environment having a Rayleigh distribution which is a basic radio wave intensity distribution of multiwave propagation is common. Even when the antenna characteristics are evaluated, such a Rayleigh fading environment is simulated to evaluate the antenna characteristics.

  On the other hand, in wireless communication systems such as LTE, WiMAX (Worldwide Interoperability for Microwave Access), W-CDMA (Wideband-Code Division Multiple Access), WLAN (Wireless Local Area Network), etc., each encoding system (for example, turbo code etc.) ), Packet communication is performed in encoding units.

  Therefore, as shown in FIG. 2, if the propagation path fluctuation of the radio signal is continuous within the coding unit and has a Rayleigh distribution, the characteristic evaluation such as the BLER determination may be performed within the coding unit. In addition, discontinuities may occur between coding units.

  In other words, if the amplitude of the radio signal is continuous within the coding unit and the radio wave intensity distribution is Rayleigh distribution, the transmission characteristics are continuously enhanced even if the coding unit is discontinuous. It is the same as the characteristics of the changing Rayleigh fading environment.

  Here, conventionally, a baseband signal (data sequence) is generated in one encoding unit (1 ms), and several tens of ms having a desired correlation between multipaths based on the baseband signal in one encoding unit. A plurality of signals (synthetic signals) for several seconds were generated.

  Thus, conventionally, the function for generating a baseband signal and the function for generating a composite signal by correlating the baseband signal are different because the time scale of the signal to be processed is different. Consisted of blocks.

  On the other hand, the antenna characteristic evaluation system 1 pays attention to the wireless transmission in the coding unit performed in the wireless communication system as shown in FIG. Thus, the desired correlation is obtained. For example, four coding units are grouped into one group, and a desired correlation is given to this group to generate a composite signal having a fading period of 4 ms.

  By performing such control, the difference between the time period for generating the baseband signal and the time period for generating the synthesized signal is eliminated, and processing can be performed on the same time scale. It can be composed of functional blocks.

  That is, in the antenna characteristic evaluation system 1, in order to give a desired correlation between multipaths, a plurality of coding units of about 1 ms are put together, a desired correlation is given to the group, and a short fading period of several ms is obtained. Build a fading environment by generating signals.

  With such a configuration, the apparatus scale can be reduced. In addition, even with a simple configuration of the antenna characteristic evaluation system 1, it is possible to give an arbitrary correlation to the multipath environment. Therefore, it is possible to improve convenience during the evaluation of the antenna characteristic, and to improve efficiency. Good antenna characteristic evaluation becomes possible.

  Next, an example of a communication system simulated by the antenna characteristic evaluation system 1 will be described. FIG. 3 is a diagram showing the configuration of the communication system. As a multipath environment, a system that performs communication on a propagation path of a 2 × 2 MIMO path is shown.

  The communication system 60 includes a base station 6 and a mobile terminal 7. The base station 6 includes antennas 6a and 6b. The data series a1 is transmitted from the antenna 6a, and the data a2 is transmitted from the antenna 6b.

  The mobile terminal 7 includes an antenna 7a, an antenna 7b, and a signal processing unit 7c. Each of the antennas 7a and 7b receives the data a1 and data a2 transmitted from the base station 6, and transmits them to the signal processing unit 7c. The signal processing unit 7c performs reception processing such as down-conversion, demodulation, and decoding on the received data.

  On the other hand, in the radio wave propagation environment between the base station 6 and the mobile terminal 7 shown in FIG. 3, when the radio wave of the data a1 is radiated from the antenna 6a to the propagation path, the antenna 7a is connected with the path p1a having a low radio wave intensity. And reaches the antenna 7b through a path p1b having a high radio wave intensity.

  Further, when the radio wave of data a2 is radiated from the antenna 6b to the propagation path, it reaches the antenna 7b via the path p2a having a low radio wave intensity, and reaches the antenna 7a via the path p2b having a high radio wave intensity.

  On the other hand, in the antennas 7a and 7b on the mobile terminal 7 side, the data a1 and a2 are combined and received with a magnitude corresponding to the strength of the propagation path. In the case of FIG. 3, the antenna 7a receives the data a2 with a high intensity and the data a1 with a low intensity. Further, the antenna 7b receives the data a1 with a high intensity and the data a2 with a low intensity.

  When the antenna characteristic evaluation system 1 performs the antenna characteristic evaluation by simulating the communication system 60 as described above, the characteristic evaluation of the antennas 7a and 7b is performed by arbitrarily changing the correlation between the transmission antennas. It will be.

  Therefore, the paths p1a and p1b radiated from the antenna 6a and the paths p2b and p2a radiated from the antenna 6b can be set to arbitrary correlations (for example, no correlation (correlation is zero)). Or

  Next, control for setting the correlation performed by the combined signal generation unit 10 of the antenna characteristic evaluation system 1 will be described. FIG. 4 is a diagram illustrating an example of correlation setting. In the following description, an example is given in which the correlation is given with eight coding units as one unit. In addition, as an arbitrary correlation, the correlation is set to zero.

  The synthesized signal generator 10 generates data series d1 and d2 therein. In the data series d1, the data X1 is set as one coding unit, and the eight data X1 are set as one set. Further, in the data series d2, the data X2 is set as one coding unit, and the eight data X2 are set as one set (note that the data series d1 and d2 are numbered # 1 to # 8 in order from the left). .

  In the case of making the path corresponding to the data sequence d1 and the path corresponding to d2 uncorrelated, in the example of FIG. 4, orthogonal code sequences (+1, +1) are provided for each of the eight encoding units of the data sequence d1. , +1, +1, +1, +1, +1, +1). In addition, orthogonal code sequences (+1, +1, +1, +1, -1, -1, -1, -1) are multiplied for each data X2 of the eight encoding units of the data sequence d2.

  That is, for the data series d1, the data X1 (# 1 to # 8) is multiplied by the orthogonal code (+1). For data series d2, data X2 (# 1 to # 4) is multiplied by orthogonal code (+1), and data X2 (# 5 to # 8) is multiplied by orthogonal code (-1). Then, the data series d2-1 is generated. The data series d1 and the data series d2-1 are uncorrelated in the propagation environment by performing such processing.

  Here, the data X1 (# 1 to # 8) of the data series d1 is +1 as propagation path information, and in the data series d2-1, the propagation path is up to the data X2 (# 1 to # 4). Is +1, and until the data X2 (# 5 to # 8), the propagation path information is -1.

  Accordingly, if the data series d1 and d2-1 are multiplied by the propagation path information for each coding unit and added, (1 × 1) + (1 × 1) + (1 × 1) + (1 × 1) + (1 × (−1)) + (1 × (−1)) + (1 × (−1)) + (1 × (−1)) = 0, so that the data series d1, d2− It can be seen that 1s have zero correlation with each other and are not correlated.

  The composite signal generation unit 10 generates a composite signal by adding the data series d1 and the data series d2-1 for each coding unit. For example, this combined signal corresponds to the combined signal v1 for radiating the radio wave having the Doppler frequency Δf1, corresponding to the configuration shown in FIG.

  Further, in the data series d2-1, there is a portion P1 where the propagation environment is discontinuous between the coding units, but the data of eight coding units is grouped into one and the correlation is set to the group. Therefore, the transmission characteristics are not affected, and there is no problem in performing the antenna characteristic evaluation.

In addition, when the correlation between the paths corresponding to the above two data series is uncorrelated in the propagation environment, it is expressed by the following expression (1). Note that X ^* in the formula (1) indicates a complex conjugate of X (when X = a + jb, the complex conjugate X ^* of X is X ^* = a−jb). Θ ₁ is a uniform random number with an initial phase of 0 to 2π, and exp (jθ ₁ ) represents an orthogonal code.

(X1 ^* · X2 · exp (jθ ₁ )) + (X1 ^* · X2 · exp (jθ ₁ )) + (X1 ^* · X2 · exp (jθ ₁ )) + (X1 ^* · X2 · exp (jθ ₁ )) ) + (X1 ^* · X2 · (−exp (jθ ₁ ))) + (X1 ^* · X2 · (−exp (jθ ₁ ))) + (X1 ^* · X2 · (−exp (jθ ₁ ))) + (X1 ^* · X2 · (−exp (jθ ₁ ))) = 0 (1)
FIG. 5 is a diagram illustrating an example of the correlation setting. An example in which the data sequence is uncorrelated with an orthogonal code sequence pattern different from FIG. 4 is shown. In the case of making the path corresponding to the data sequence d1 and the path corresponding to d2 uncorrelated, in the example of FIG. 5, orthogonal code sequences (+1, +1) are provided for each of the eight encoding units of the data sequence d1. , +1, +1, +1, +1, +1, +1). In addition, orthogonal code sequences (+1, +1, −1, −1, +1, +1, −1, −1) are multiplied for each data X2 of 8 encoding units of the data sequence d2.

  That is, for the data series d1, the data X1 (# 1 to # 8) is multiplied by the orthogonal code (+1). For the data series d2, the data X2 (# 1, # 2) is multiplied by the orthogonal code (+1), the data X2 (# 3, # 4) is multiplied by the orthogonal code (-1), Data X2 (# 5, # 6) is multiplied by orthogonal code (+1), and data X2 (# 7, # 8) is multiplied by orthogonal code (-1) to generate data series d2-2. The data series d1 and the data series d2-2 are uncorrelated by performing such processing.

  Here, the data X1 (# 1 to # 8) of the data series d1 is +1 as the propagation path information. Also, data X2 (# 1, # 2) of data series d2-2 is +1 as propagation path information, and data X2 (# 3, # 4) is -1 as propagation path information. , Data X2 (# 5, # 6) is +1 as propagation path information, and data X2 (# 7, # 8) is -1 as propagation path information.

  Therefore, if the data series d1 and d2-2 are multiplied by channel information for each coding unit and added, (1 × 1) + (1 × 1) + (1 × (−1)) + Since (1 × (−1)) + (1 × 1) + (1 × 1) + (1 × (−1)) + (1 × (−1)) = 0, the data series d1, d2− It can be seen that 2 has zero correlation with each other and is uncorrelated.

  Further, in the data series d2-2, there are places P2 to P4 where the propagation environment is discontinuous between the coding units, but the data of the eight coding units is grouped into one and the correlation is made to the group. Since it is set, the transmission characteristics are not affected, and there is no problem in performing the antenna characteristic evaluation.

  The composite signal generation unit 10 generates a composite signal by adding the data series d1 and the data series d2-2 for each coding unit. For example, this combined signal corresponds to the combined signal v2 for radiating the radio wave having the Doppler frequency Δf2 if it corresponds to the configuration shown in FIG.

When the correlation between the two data series is uncorrelated in the propagation environment, the following expression (2) is given.
(X1 ^* · X2 · exp (jθ ₁ )) + (X1 ^* · X2 · exp (jθ ₁ )) + (X1 ^* · X2 · (−exp (jθ ₁ ))) + (X1 ^* · X2 · (− exp (jθ ₁ ))) + (X1 ^* · X2 · exp (jθ ₁ )) + (X1 ^* · X2 · exp (jθ ₁ )) + (X1 ^* · X2 · (−exp (jθ ₁ ))) + (X1 ^* · X2 · (−exp (jθ ₁ ))) = 0 (2)
FIG. 6 is a diagram illustrating an example of correlation setting. 4 and 5, the code of the data series d1 is not changed, and the orthogonality is created by multiplying only the predetermined data of the data series d2 by the orthogonal code (-1). In the example of FIG. The predetermined data of the data series d1 is also multiplied by the orthogonal code (-1).

  When the path corresponding to the data sequence d1 and the path corresponding to d2 are made uncorrelated, in the example of FIG. 6, orthogonal code sequences (+1, +1) are provided for each of the eight encoding units of the data sequence d1. , -1, -1, -1, -1, +1, +1). In addition, orthogonal code sequences (+1, +1, −1, −1, +1, +1, −1, −1) are multiplied for each data X2 of 8 encoding units of the data sequence d2.

  That is, for the data series d1, the data X1 (# 1, # 2) is multiplied by the orthogonal code (+1), the data X1 (# 3- # 6) is multiplied by the orthogonal code (-1), and the data X1 (# 7, # 8) is multiplied by an orthogonal code (+1) to generate a data series d1-2.

  For the data series d2, the data X2 (# 1, # 2) is multiplied by the orthogonal code (+1), the data X2 (# 3, # 4) is multiplied by the orthogonal code (-1), Data X2 (# 5, # 6) is multiplied by orthogonal code (+1), and data X2 (# 7, # 8) is multiplied by orthogonal code (-1) to generate data series d2-2. The data series d1-2 and the data series d2-2 are uncorrelated by performing such processing.

  Here, the data X1 (# 1, # 2) of the data series d1-2 is +1 as the propagation path information, and the data X1 (# 3 to # 6) is -1 as the propagation path information. Yes, data X1 (# 7, # 8) is +1 as propagation path information.

  Also, data X2 (# 1, # 2) of data series d2-2 is +1 as propagation path information, and data X2 (# 3, # 4) is -1 as propagation path information. , Data X2 (# 5, # 6) is +1 as propagation path information, and data X2 (# 7, # 8) is -1 as propagation path information.

  Therefore, if the data series d1-2 and d2-2 are multiplied by the propagation path information for each coding unit and added, (1 × 1) + (1 × 1) + ((− 1) × ( −1)) + ((− 1) × (−1)) + ((− 1) × 1) + ((− 1) × 1) + (1 × (−1)) + (1 × (−1) )) = 0, it can be seen that the data series d1-2 and d2-2 have zero correlation with each other and are uncorrelated.

  In the data series d1-2, there are places P5 and P6 where the propagation environment is discontinuous between the coding units, and in the data series d2-2, places P2 to P4 where the propagation environment is discontinuous between the coding units. However, there is no influence on the transmission characteristics because the data of 8 coding units is grouped and the correlation is set to the group, and it is a problem in performing the antenna characteristics evaluation. There is no.

  Further, as described above, by generating an uncorrelated multipath using different orthogonal codes for each transmission antenna, not only the phase but also the amplitude can be made different.

When the correlation between the above two data series is uncorrelated in the propagation environment, it is expressed by the following expression (3) when expressed in a complex number expression format.
(X1 ^* · X2 · exp (jθ ₁ )) + (X1 ^* · X2 · exp (jθ ₁ )) + (X1 ^* · (−exp (jθ ₂ )) · X2 · (−exp (jθ ₁ ))) + (X1 ^* · (−exp (jθ ₂ )) · X2 · (−exp (jθ ₁ ))) + (X1 ^* · (−exp (jθ ₂ )) · X2 · exp (jθ ₁ )) + (X1 ^* · (−exp (jθ ₂ )) · X 2 · exp (jθ ₁ )) + (X ₁ ^* · X 2 · (−exp (jθ ₁ ))) + (X 1 ^* · X 2 · (−exp (jθ ₁ )) ) = 0 ... (3)
In the correlation settings shown in FIGS. 4 to 6 above, Walsh codes are used for the orthogonal code sequences. When Walsh codes are used, orthogonal codes can be stored using a simple memory. The Walsh code will be briefly described below.

FIG. 7 is a diagram for explaining the Walsh code. The matrix A ₁ has row vectors (1, 1), (1, −1), and these two row vectors are orthogonal (∵1 × 1 + 1 × (−1) = 0).
The matrix A ₂ has row vectors (A ₁ , A ₁ ), (A ₁ , −A ₁ ). Since A ₁ is the 2 × 2 matrix described above, when the matrix A ₂ is written for each element, four row vectors (1, 1, 1, 1), (1, -1, 1, -1), ( 1, 1, -1, -1), (1, -1, -1, 1).

Here, it can be seen that the matrix A ₂ is orthogonal even if any two row vectors are extracted. For example, row vectors (1, 1, 1, 1), (1, -1, 1, -1) are orthogonal, and row vectors (1, -1, 1, -1), (1,- 1, -1, 1) are also orthogonal.

As the above operation is continued, the matrix _An has row vectors (A _n−1 , A _n−1 ), (A _n−1 , −A _n−1 ), and such a matrix Is called the Hadamard matrix. A row vector of the Hadamard matrix is called a Walsh code.

  As the orthogonal code, not only the Walsh code as described above but also a code related to a Fourier series of {exp [j2πnk / N], (n, k = 0,1,..., N-1)}, for example. There is a code that periodically shifts the M sequence and adds 1 at the end, and these may be used.

  Next, a block configuration for generating a composite signal from the data series d1 and d2 will be described. FIG. 8 is a diagram showing a block configuration for generating a composite signal. This corresponds to the contents shown in FIG.

Multiplier 101a is the data X2 of the coding unit of the data sequence d2, perpendicular to the order code _{exp (jθ 1), exp (} jθ 1), exp (jθ 1), exp (jθ 1), - exp (jθ 1) _{, -exp (jθ 1), -} exp (jθ 1), - multiplying the exp (jθ _1). The multiplication outputs are (X2 · exp (jθ ₁ )), (X2 · exp (jθ ₁ )), (X2 · exp (jθ ₁ )), (X2 · exp (jθ ₁ )), (X2 · (−exp (Jθ ₁ ))), (X2 · (−exp (jθ ₁ ))), (X2 · (−exp (jθ ₁ ))), (X2 · (−exp (jθ ₁ ))) ) Corresponds to the data series d2-1 in FIG.

The adder 102 adds the data X1 of the coding unit of the data series d1 to these multiplication outputs, and outputs a synthesized signal v. The composite signal v is {X1 + (X2 · exp (jθ ₁ ))} + {X1 + (X2 · exp (jθ ₁ ))} + {X1 + (X2 · exp (jθ ₁ ))} + {X1 + (X2 · exp (Jθ ₁ ))} + {X1 + (X2 · (−exp (jθ ₁ )))} + {X1 + (X2 · (−exp (jθ ₁ )))} + {X1 + (X2 · (−exp (jθ ₁ )))} + {X1 + (X2 · (−exp (jθ ₁ )))}.

FIG. 9 is a diagram showing a block configuration for generating a composite signal. This corresponds to the contents shown in FIG. Multiplier 101a is the data X2 of the coding unit of the data sequence d2, perpendicular to the order code _{exp (jθ 1), exp (} jθ 1), - exp (jθ 1), - exp (jθ 1), exp (jθ 1 ), Exp (jθ ₁ ), −exp (jθ ₁ ), −exp (jθ ₁ ). The multiplication outputs are (X2 · exp (jθ ₁ )), (X2 · exp (jθ ₁ )), (X2 · (−exp (jθ ₁ ))), (X2 · (−exp (jθ ₁ ))), (X2 · exp (jθ ₁ )), (X2 · exp (jθ ₁ )), (X2 · (−exp (jθ ₁ ))), (X2 · (−exp (jθ ₁ )))) ) Corresponds to the data series d2-2 in FIG.

The adder 102 adds the data X1 of the coding unit of the data series d1 to these multiplication outputs, and outputs a synthesized signal v. The combined signal v is {X1 + (X2 · exp (jθ ₁ ))} + {X1 + (X2 · exp (jθ ₁ ))} + {X1 + (X2 · (−exp (jθ ₁ )))} + {X1 + ( X2 · (−exp (jθ ₁ )))} + {X1 + (X2 · exp (jθ ₁ ))} + {X1 + (X2 · exp (jθ ₁ ))} + {X1 + (X2 · (−exp (jθ ₁₎ )))} + {X1 + (X2 · (−exp (jθ ₁ )))}.

FIG. 10 is a diagram showing a block configuration for generating a composite signal. This corresponds to the contents shown in FIG. Multiplier 101a is the data X2 of the coding unit of the data sequence d2, perpendicular to the order code _{exp (jθ 1), exp (} jθ 1), - exp (jθ 1), - exp (jθ 1), exp (jθ 1 ), Exp (jθ ₁ ), −exp (jθ ₁ ), −exp (jθ ₁ ). The multiplication outputs are (X2 · exp (jθ ₁ )), (X2 · exp (jθ ₁ )), (X2 · (−exp (jθ ₁ ))), (X2 · (−exp (jθ ₁ ))), (X2 · exp (jθ ₁ )), (X2 · exp (jθ ₁ )), (X2 · (−exp (jθ ₁ ))), (X2 · (−exp (jθ ₁ )))) ) Corresponds to the data series d2-2 in FIG.

Further, the multiplier 101b is the data X1 of the coding unit of the data sequence d1, the orthogonal code exp sequentially _{(jθ 2), exp (jθ} 2), - exp (jθ 2), - exp (jθ 2), - exp _{(jθ 2), - exp (} jθ 2), exp (jθ 2), multiplying the exp (jθ _2). The multiplication outputs are (X1 · exp (jθ ₂ )), (X1 · exp (jθ ₂ )), (X1 · (−exp (jθ ₂ ))), (X1 · (−exp (jθ ₂ ))), (X1 · (−exp (jθ ₂ ))), (X1 · (−exp (jθ ₂ ))), (X1 · exp (jθ ₂ )), (X1 · exp (jθ ₂ )) ) Corresponds to the data series d1-2 in FIG.

The adder 102 adds these two multiplication outputs for each coding unit, and outputs a synthesized signal v. The combined signal v is {(X1 · exp (jθ ₂ )) + (X2 · exp (jθ ₁ ))} + {(X1 · exp (jθ ₂ )) + (X2 · exp (jθ ₁ ))} + { (X1 · (−exp (jθ ₂ ))) + (X2 · (−exp (jθ ₁ )))} + {(X1 · (−exp (jθ ₂ ))) + (X2 · (−exp (jθ ₁₎ )))} + {(X1 · (−exp (jθ ₂ ))) + (X2 · exp (jθ ₁ ))} + {(X1 · (−exp (jθ ₂ ))) + (X2 · exp (jθ ₁ ))} + {(X1 · exp (jθ ₂ )) + (X2 · (−exp (jθ ₁ )))} + {(X1 · exp (jθ ₂ )) + (X2 · (−exp (jθ ₁₎ )))}.

  Next, a detailed configuration of the combined signal generation unit 10 (signal generation device) will be described. In addition, the structure of the synthetic | combination signal generation part 10 at the time of applying to the antenna characteristic evaluation system in the case of producing | generating eight synthetic | combination signals v1-v8 is demonstrated. First, the configuration of the antenna characteristic evaluation system is shown.

  FIG. 11 is a diagram illustrating a configuration example of an antenna characteristic evaluation system. The antenna characteristic evaluation system 1-1 includes transmission antennas 23-1 to 23-8, evaluation antennas 24a and 24b, a combined signal generation unit 10, upconverters 22-1 to 22-8, and an evaluation unit 30.

  Since the basic configuration is the same as that of the antenna characteristic evaluation system 1 of FIG. 1, the composite signal generation unit 10 outputs eight composite signals v1 to v8 when only different portions are shown. Each of up-converters 22-1 to 22-8 receives composite signals v1 to v8, performs up-conversion, and transmits Doppler frequencies Δf1 to Δf8 in anechoic chamber 20 via transmitting antennas 23-1 to 23-8. Radiates to.

  FIG. 12 is a diagram illustrating a configuration of the composite signal generation unit 10. The combined signal generation unit 10 includes an orthogonal code generation unit 11, a calculation unit 12, a data sequence generation unit 13, a multiplication processing unit 14, a combination processing unit 15, and an output processing unit 16.

  The orthogonal code generation unit 11 includes orthogonal code sequence generation units 11-1 to 11-N, and generates an orthogonal code sequence. The arithmetic unit 12 multiplies the orthogonal code sequence by a correlation parameter for giving a desired correlation to generate a code sequence giving the desired correlation.

  The data series generation unit 13 generates a data series that is a digital baseband signal. The multiplication processing unit 14 multiplies the data sequence and the code sequence. The synthesis processing unit 15 weights and synthesizes a plurality of multiplication results to generate a synthesized signal.

  The output processing unit 16 includes D / A units 16 a-1 to 16 a-8 and filters 16 b-1 to 16 b-8, and performs output interface processing (removal of aliasing distortion associated with D / A conversion and D / A conversion). ) And output to the up-converter 22.

  Next, the orthogonal code sequence generation units 11-1 to 11-N will be described. The orthogonal code sequence generators 11-1 to 11-N correspond to digital generators that can oscillate orthogonal code sequences of a plurality of different patterns.

FIG. 13 is a diagram showing an orthogonal code sequence generated by the orthogonal code sequence generator. In the orthogonal code sequence, a number (data sequence identification number) for identifying a data sequence is m, a number (path identification number) for identifying a path is k, and an orthogonal code generated by one orthogonal code sequence generation unit. When a number for identifying a sequence pattern (orthogonal code sequence pattern identification number) is n, it is expressed as x _{m, kn} . Note that n is equal to the number of transmission antennas.

The orthogonal code sequence generator 11-1 shown in FIG. 13 generates an orthogonal code sequence for a data sequence having a data sequence identification number of 1 and a path having a path identification number of 1. Further, since the number of patterns of the orthogonal code sequence is eight (n = 1 to 8), the orthogonal code sequences x _1,1-1 , x _1,1-2 , x _1,1-3 , x _{1,1- 4} , x _1,1-5 , x _1,1-6 , x _1,1-7 , x _1,1-8 are generated.

Furthermore, when the correlation is given by using eight coding units as one unit, the number of orthogonal codes of each orthogonal code sequence is eight. For example, the orthogonal code sequence x _1,1-1 has, as orthogonal codes, exp (jθ _1,1-1 ), exp (jθ _1,1-1 ), exp (jθ _1,1-1 ), exp (jθ _1,1-1 ), exp ( _jθ1,1-1 ), exp ( _jθ1,1-1 ), exp ( _jθ1,1-1 ), exp ( _jθ1,1-1 ) Is generated.

Further, the orthogonal code sequence x _1,1-2 includes, as orthogonal codes, exp (jθ _1,1-2 ), exp (jθ _1,1-2 ), exp (jθ _1,1-2 ), exp (jθ _{1,1-2), - exp (jθ 1,1-2} ), - exp (jθ 1,1-2), - exp (jθ 1,1-2), - exp (jθ 1,1-2) (The other orthogonal code sequences similarly generate eight orthogonal codes).

FIG. 14 is a diagram showing an orthogonal code sequence generated by the orthogonal code sequence generator. The orthogonal code sequence generation unit 11-2 illustrated in FIG. 14 generates an orthogonal code sequence for a path having a data sequence identification number of 2 and a path identification number of 1. Since the number of patterns of the orthogonal code sequence is 8 (n = 1 to 8), the orthogonal code sequences x _2,1-1 , x _2,1-2 , x _2,1-3 , x _{2,1 -4} , x _2,1-5 , x _2,1-6 , x _2,1-7 , x _2,1-8 will be generated.

Further, since the correlation is given by using eight coding units as one group, the number of orthogonal codes of each orthogonal code sequence is eight. For example, the orthogonal code sequence x _2,1-1 as orthogonal _{codes, exp (jθ 2,1-1), exp} (jθ 2,1-1), - exp (jθ 2,1-1), - exp ( _{Jθ 2,1-1} ), exp (jθ _2,1-1 ), exp (jθ _2,1-1 ), _-exp (jθ _2,1-1 ), _-exp (jθ _2,1-1 ) Are generated.

Further, the orthogonal code sequence x _2,1-2 as orthogonal _{codes, exp (jθ 2,1-2), exp} (jθ 2,1-2), - exp (jθ 2,1-2), - exp _{(jθ 2,1-2), - exp (} jθ 2,1-2), - exp (jθ 2,1-2), exp (jθ 2,1-2), exp (jθ 2,1-2) (The other orthogonal code sequences have eight orthogonal codes as well).

Next, the calculation unit 12 will be described. The calculation unit 12 performs a matrix calculation to calculate a correlated vector y from the uncorrelated vector x. FIG. 15 is a diagram illustrating an example of matrix calculation. The calculation unit 12 multiplies the orthogonal code sequence column vector output from the orthogonal code generation unit 11 by a matrix composed of correlation parameters to generate a code sequence for giving a desired correlation (hereinafter, matrix calculation). The later code sequence is denoted _{by ym, kn} ).

In Figure 15, shows an example of a matrix operation of 4 × 4, column vectors of the orthogonal code sequence _{(x 1,1-1, x 1,1-5, x} 2,1-1, x 2,1- ₅ ) is multiplied by a matrix H composed of elements of 4 × 4 correlation parameters, and a column vector (y _1,1-1 , y _1,1-5 , y _2,1-1 , y) of the code sequence is multiplied. _2,1-5 ).

  By performing such matrix operation, a code sequence for giving arbitrary correlation to the data sequence can be generated. If it is desired to make the desired correlation uncorrelated, that is, if a synthesized signal is generated from the orthogonal code sequence itself output from the orthogonal code generator 11 and the synthesized signal is desired to be uncorrelated, the matrix H is A matrix operation may be performed using a unit matrix.

  Next, the multiplication processing unit 14 will be described. The multiplication processing unit 14 multiplies the data sequence output from the data sequence generation unit 13 and the code sequence output from the calculation unit 12 for each coding unit.

FIG. 16 is a diagram illustrating an example of multiplication processing. The data sequence {X1, X1,...} Is shown multiplied by the code sequence y (hereinafter, the multiplication value after the multiplication processing is indicated as ν _{m, kn} ).

Each of the multipliers 14-1 to 14-8 applies the code sequence y _1,1-1 , y _1,1-2 , y _1,1-3 , y _{1,1-4 to} the data X1 of the data sequence. , Y _1,1-5 , y _1,1-6 , y _1,1-7 , y _1,1-8 . And the multiplication values ν _1,1-1 , ν _1,1-2 , ν _1,1-3 , ν _1,1-4 , ν _1,1-5 , ν _1,1-6 , ν _{1,1 -7} and ν _1,1-8 are output. Similar processing is performed on the data series {X2, X2,.

  Next, the synthesis processing unit 15 and the output processing unit 16 will be described. FIG. 17 is a diagram illustrating the configuration of the synthesis processing unit 15 and the output processing unit 16. The synthesis processing unit 15 includes weighting synthesis units 15-1 to 15-8.

Each of the weighting combining units 15-1 to 15-8 multiplies a plurality of multiplication values ν necessary for generating a combined signal by a weighting constant W, and calculates and outputs the sum of the weighted multiplication values ν.
The output processing unit 16 includes D / A units 16a-1 to 16a-8 and filters (folding filters) 16b-1 to 16b-8. The D / A units 16a-1 to 16a-8 convert the digital combined signal output from the combining processing unit 15 into an analog combined signal. The aliasing filters 16b-1 to 16b-8 filter the analog synthesized signal to remove aliasing distortion generated during D / A conversion, generate synthesized signals v1 to v8, and transmit them to the upconverter 22 side.

  Next, a modified example will be described. In the above description, the data series is grouped into an arbitrary number of coding units (eight coding units in the above example) with reference to the data series coding unit.

  On the other hand, in the modified example, the case where channel estimation is performed as an evaluation item is considered, and the range expanded to the data portion necessary for channel estimation before and after the encoding unit is set as one unit (processing unit). ), And a data series is grouped into an arbitrary number of processing units.

FIG. 18 is a diagram for explaining a modification. The data series D1 of the wireless communication system in the actual environment is different data for each encoding unit, such as data X _1,1 , X _1,2 , X _1,3 . That is, data X _1,1 , data X _1,2 and data X _1,3 usually have different data values.

On the other hand, in the antenna characteristic evaluation system 1, when measuring the like BLER, since need not be different data values, for example, as data series D1a, the same data X _{1, 2} handles plural consecutive data sequence .

  Here, in an actual wireless communication system, channel estimation is performed when demodulating. This channel estimation may use data (pilot signal) other than the data of the coding unit to be channel estimated.

It is assumed that pilot signal p1 is inserted into data X _1,1 , pilot signals p2 and p3 are inserted into data X _1,2 , and pilot signal p4 is inserted into data X _1,3 .
In this case, when performing channel estimation data X _{1, 2,} not only the pilot signals p2, p3, also uses the pilot signal p1, p4, or perform channel estimation of a data X _{1, 2.}

  Therefore, when it is desired to evaluate channel estimation, if the range expanded to the data portion necessary for channel estimation before and after the coding unit is set as one processing unit, and the data series is grouped as one unit in the processing unit, Real environment system can be simulated.

In a variant, for the data X _{1, 2} in the middle, from around the pilot signals p1 of data preceding the data X _{1, 2} are inserted, the data in the subsequent data X _{1, 2} pilots The range R up to the periphery where the signal p4 is inserted may be a new processing unit.

  Then, the data series is grouped into one unit in an arbitrary number of processing units, and the group is multiplied by a code series that gives a desired correlation to generate a plurality of synthesized signals. With such a configuration, it is possible to perform channel estimation evaluation equal to channel estimation performed in the real environment system.

(Supplementary note 1) In an antenna characteristic evaluation system for evaluating antenna characteristics,
An evaluation antenna that is an antenna to be evaluated; and
A plurality of transmitting antennas that radiate radio waves to the evaluation antenna;
Generating a data sequence that is a baseband signal, and generating a synthesized signal from the data sequence;
An up-converter connected to the transmitting antenna and up-converting the frequency of the combined signal to the frequency of the radio wave;
An evaluation unit that is connected to the evaluation antenna and performs evaluation of the antenna characteristics of the evaluation antenna when the radio wave is received;
With
The synthesized signal generator is
When the data series is divided by a certain processing unit, the data series is grouped into one unit in an arbitrary number of processing units, and a code sequence that gives a desired correlation to the group of the data series is multiplied, A composite signal generation process for generating a plurality of composite signals is performed.
An antenna characteristic evaluation system characterized by that.

  (Additional remark 2) The said synthetic | combination signal production | generation part makes the said processing unit the said encoding unit with respect to the said data sequence comprised by the encoding unit, and unites a data sequence in the arbitrary number of said encoding units. The antenna characteristic evaluation system according to appendix 1, wherein the combined signal generation process is performed.

  (Additional remark 3) The said synthetic | combination signal production | generation part makes the range extended to the data part required for the channel estimation before and behind the said encoding unit with respect to the said data series comprised by an encoding unit as the said processing unit, Arbitrary The antenna characteristic evaluation system according to appendix 1, wherein the combined signal generation process is performed by grouping the data series into a number of the processing units.

(Supplementary Note 4) The synthesized signal generation unit
An orthogonal code generation unit for generating an orthogonal code sequence;
An arithmetic unit for multiplying the orthogonal code sequence by a correlation parameter for giving a desired correlation and generating the code sequence giving the desired correlation;
The antenna characteristic evaluation system according to supplementary note 1, which includes the antenna characteristic evaluation system.

(Additional remark 5) The said orthogonal code production | generation part produces | generates the said different orthogonal code series for every said transmission antenna, The antenna characteristic evaluation system of Additional remark 4 characterized by the above-mentioned.
(Additional remark 6) The said orthogonal code production | generation part produces | generates the said orthogonal code series by a Walsh code, The antenna characteristic evaluation system of Additional remark 4 characterized by the above-mentioned.

(Supplementary note 7) In a signal generator for performing signal generation control,
A data sequence generation unit that generates a data sequence that is a baseband signal, an orthogonal code generation unit that generates an orthogonal code sequence, a correlation parameter for giving the desired correlation to the orthogonal code sequence, and a desired correlation A synthesis unit that generates a code sequence provided with a data, a multiplication processing unit that multiplies the data sequence and the code sequence, and a synthesis processing unit that weights and synthesizes a plurality of multiplication results to generate a synthesized signal A signal generation control unit;
An output processing unit that performs output interface processing of the combined signal output from the combining processing unit;
Have
The combined signal generation control unit divides the data series into a certain number of processing units, makes the data series into one unit for any number of the processing units, and provides desired correlation to the unit of the data series. Multiplying the given code sequence to perform a composite signal generation process for generating a plurality of the composite signals;
A signal generator characterized by that.

  (Supplementary Note 8) The synthesized signal generation control unit uses the processing unit as the coding unit for the data sequence formed of coding units, and sets a single data sequence in any number of the coding units. The signal generator according to appendix 7, wherein the combined signal generation process is performed as a unit.

  (Additional remark 9) The said synthetic | combination signal generation | occurrence | production control part makes the said process unit the range extended to the data part required for the channel estimation before and behind the said encoding unit with respect to the said data series comprised by the encoding unit, and is arbitrary. 8. The signal generator according to appendix 7, wherein the combined signal generation process is performed by grouping the data series into a number of the processing units.

(Additional remark 10) The said orthogonal code production | generation part produces | generates the said different orthogonal code series for every transmission antenna, The signal generator of Additional remark 7 characterized by the above-mentioned.
(Additional remark 11) The said orthogonal code production | generation part produces | generates the said orthogonal code sequence by a Walsh code, The signal generator of Additional remark 7 characterized by the above-mentioned.

DESCRIPTION OF SYMBOLS 1 Antenna characteristic evaluation system 10 Synthetic signal production | generation part 20 Anechoic chamber 22-1 to 22-4 Up converter 23-1 to 23-4 Transmission antenna 24a, 24b Evaluation antenna 30 Evaluation part 31 Antenna characteristic evaluation board 32 Evaluation terminal (DELTA) f1- Δf4 Doppler frequency v1 to v4 composite signal

Claims (8)

In the antenna characteristics evaluation system that evaluates antenna characteristics,
An evaluation antenna that is an antenna to be evaluated; and
A plurality of transmitting antennas that radiate radio waves to the evaluation antenna;
Generating a data sequence that is a baseband signal, and generating a synthesized signal from the data sequence;
An up-converter connected to the transmitting antenna and up-converting the frequency of the combined signal to the frequency of the radio wave;
An evaluation unit that is connected to the evaluation antenna and performs evaluation of the antenna characteristics of the evaluation antenna when the radio wave is received;
With
The synthesized signal generator is
When the data series is divided by a certain processing unit, the data series is grouped into one unit in an arbitrary number of processing units, and a code sequence that gives a desired correlation to the group of the data series is multiplied, A composite signal generation process for generating a plurality of composite signals is performed.
An antenna characteristic evaluation system characterized by that.   The synthesized signal generating unit sets the processing unit as the coding unit for the data sequence configured by a coding unit, groups the data sequence as an arbitrary number of the coding units, and The antenna characteristic evaluation system according to claim 1, wherein a combined signal generation process is performed.   The synthesized signal generation unit uses the range of the data series formed of coding units, which is expanded to the data portion necessary for channel estimation before and after the coding unit, as the processing unit, and an arbitrary number of the processing The antenna characteristic evaluation system according to claim 1, wherein the combined signal generation process is performed by grouping the data series into one unit. The synthesized signal generator is
An orthogonal code generation unit for generating an orthogonal code sequence;
An arithmetic unit for multiplying the orthogonal code sequence by a correlation parameter for giving a desired correlation and generating the code sequence giving the desired correlation;
The antenna characteristic evaluation system according to claim 1, further comprising:   The antenna characteristic evaluation system according to claim 4, wherein the orthogonal code generation unit generates a different orthogonal code sequence for each transmission antenna.   The antenna characteristic evaluation system according to claim 4, wherein the orthogonal code generation unit generates the orthogonal code sequence using a Walsh code. In a signal generator for performing signal generation control,
A data sequence generation unit that generates a data sequence that is a baseband signal, an orthogonal code generation unit that generates an orthogonal code sequence, a correlation parameter for giving the desired correlation to the orthogonal code sequence, and a desired correlation A synthesis unit that generates a code sequence provided with a data, a multiplication processing unit that multiplies the data sequence and the code sequence, and a synthesis processing unit that weights and synthesizes a plurality of multiplication results to generate a synthesized signal A signal generation control unit;
An output processing unit that performs output interface processing of the combined signal output from the combining processing unit;
Have
The combined signal generation control unit divides the data series into a certain number of processing units, makes the data series into one unit for any number of the processing units, and provides desired correlation to the unit of the data series. Multiplying the given code sequence to perform a composite signal generation process for generating a plurality of the composite signals;
A signal generator characterized by that.   The combined signal generation control unit sets the processing unit as the encoding unit for the data sequence configured by the encoding unit, and groups the data sequence as an arbitrary number of the encoding units, The signal generator according to claim 7, wherein the combined signal generation process is performed.

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