Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It should be noted that in the description of the present invention, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises an element. The orientation or positional relationship indicated by the terms "upper", "lower", etc. are based on the orientation or positional relationship shown in the drawings, are merely for convenience of description and to simplify the description, and are not indicative or implying that the apparatus or elements in question must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention. Unless specifically stated or limited otherwise, the terms "mounted," "connected," "coupled," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected, mechanically connected, communicatively connected, electrically connected, directly connected, or indirectly connected via an intermediate medium, or in communication with the interior of two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
The terms "first," "second," and the like in this specification are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged, as appropriate, such that embodiments of the present invention may be implemented in sequences other than those illustrated or described herein, and that the objects identified by "first," "second," etc. are generally of a type, and are not limited to the number of objects, such as the first object may be one or more. In addition, "and/or" indicates at least one of the connected objects, and the character "/", generally indicates that the associated object is an "or" relationship.
The channel simulator of the current mainstream communication instrument production manufacturer is used for electromagnetic scene simulation, and the following defects need to be overcome:
Firstly, the wireless channel has the defects of lack of measured data and great measured difficulty, and the available models are scarce. The electromagnetic spectrum and interference data can be collected by a universal spectrometer and other devices, and a plurality of civil communication companies and scientific research institutions accumulate considerable data. However, in the aspect of wireless channel data, academic research is mainly conducted towards public network scenes, and in-situ measurement data and models for complex civil scenes such as intelligent transportation, the internet of things and intelligent power grids are lacking. Meanwhile, in certain special environments (such as urban dense areas, underground facilities and the like), the requirements on channel actual measurement equipment are high, and the complexity of the environments is high, so that the research results of actual measurement channel data, modeling methods, available models and the like in civil scenes are relatively deficient, and the development of the civil wireless channel simulation technology is limited.
Secondly, the existing channel model is difficult to meet the accuracy requirement of civil complex electromagnetic environment simulation. Complex and unique propagation characteristics exist in civil environments, such as multipath effects, building reflections, signal shadowing, etc. in urban environments, which create propagation mechanisms and multipath channels that are different from typical communication scenarios, resulting in waves exhibiting unique loss and fading characteristics, with a high degree of spatial heterogeneity and frequency dependence. This makes it difficult to accurately characterize the wave propagation and channel characteristics of complex urban environments, industrial environments and other special civilian scenarios using the current empirical or analytical models of wave propagation in common use. Therefore, there is a need for more accurate and reliable wave propagation prediction techniques and platforms that support accurate characterization of dense, dynamically varying electromagnetic signals in complex environments.
In addition, the dynamic simulation capability is limited, the radio frequency bandwidth is small, and the number of switching channels is small. The current channel simulator is mainly oriented to public network base station and mobile phone terminal tests, and tests are carried out by using a civil standard channel model. Because the public network standard model only covers a few typical application scenes, and meanwhile, channel parameters are relatively fixed, in some high-dynamic and multi-scene switching civil applications, simulation time is too short (millisecond to second level), scene switching and dynamic parameter transformation capability are limited, and long-time (hour level) and multi-scene (such as intelligent traffic and Internet of things application) channel simulation requirements are difficult to meet. Meanwhile, the current channel simulator mainly aims at 4G and 5G applications, has smaller radio frequency bandwidth (in the order of hundred megahertz), and is difficult to meet the requirement of high bandwidth, especially in some applications with high data rate and low delay (such as ultra-high definition video transmission, unmanned driving and the like). In addition, civil scenes have a plurality of frequency points, large radio frequency exchange quantity and high phase consistency requirements, and the existing equipment is difficult to meet the requirements of expansibility and customization in the civil scenes.
In view of the above, the invention provides a new radio frequency signal simulation device, which mainly has four key technical improvements, namely an integrated interference and channel acquisition technology, a high-performance ray tracking simulation technology, a full-connection channel simulation technology and an ultra-large bandwidth frequency conversion technology, and aims to replace a large-scale simulation beam forming device by digital operation equivalent, realize the organic combination of virtual beams, electromagnetic interference and wireless channels, and solve the problem of phased array multi-antenna channel simulation, and is described in detail below with reference to fig. 1-13.
Fig. 1 is a schematic structural diagram of a radio frequency signal simulation device provided by the present invention, as shown in fig. 1, mainly including but not limited to a fully-connected channel simulation module.
The full-connection channel simulation module comprises a user control unit arranged on a user control platform, a channel coefficient generation unit arranged on a channel coefficient generation platform and a signal processing unit arranged on a software radio platform. The user control unit performs signal simulation control and configuration parameters including configuration of model parameters and hardware configuration parameters. The channel coefficient generating unit generates a channel impulse response matrix according to the configuration parameters input by the user control unit, and splits the channel impulse response matrix into channel impulse response coefficients of all sub-channels. And the signal processing unit carries out fading simulation processing on the input signal according to the channel impulse response coefficient and outputs a target radio frequency signal. The target radio frequency signal refers to a modulated high frequency signal, is suitable for the field of wireless communication, has higher frequency and bandwidth, and reflects the propagation effect of the signal under the specific channel condition.
In particular, compared with the existing signal simulator, the radio frequency signal simulation device provided by the invention creatively integrates a fully-connected channel simulation module and mainly comprises a user control unit, a coefficient generation unit and a hardware processing unit. The user control unit and the channel coefficient generation unit are mainly completed in software and are respectively arranged on a user control platform and a channel coefficient generation platform, the user control platform can be generally loaded on a user terminal server, and the channel coefficient generation platform is generally loaded in a cloud server.
The user control unit mainly completes a human-computer interface, and comprises input of model parameters and hardware configuration parameters, measurement of input signals, result display and the like. The model parameters mainly comprise channel parameters, scene parameters, antenna parameters and the like. The hardware configuration parameters mainly comprise the number of generated channel impulse response matrixes, the number of configured channels, whether the channel is a MIMO channel model, the center frequency, the moving speed, the simulation time and the like.
The channel coefficient generating unit generates a channel impulse response matrix mainly according to the input channel parameters, splits the generated channel impulse response matrix into sub-channel impulse response coefficients, and finally transmits the sub-channel impulse response coefficients to the fading simulator of the signal processing unit. The channel impulse response matrix adopts a mathematical matrix mode to describe attenuation and time delay characteristics of signals at different moments and on different paths when the signals propagate in all sub-channels.
The signal processing unit is mainly used for performing down-conversion, analog-to-Digital Converter (ADC), fading simulation, digital-to-Analog Converter (DAC), up-conversion and the like on the input signal, and performs mathematical operation on the input signal to simulate the channel characteristics.
The signal processing unit used by the invention has the advantages of wider bandwidth, higher operation speed, higher fixed precision and the like, and the performance of the signal processing unit is directly related to the performance index of the channel simulator, such as the frequency range, the bandwidth, the multipath resolution, the maximum multipath number, the maximum multipath time delay spread and the like.
The fading simulation is a functional core of the signal Processing unit, and the fading simulator adopted by the invention can adopt digital signal Processing (DIGITAL SIGNAL Processing, DSP) or Field-Programmable gate array (Field-Programmable GATE ARRAY, FPGA), and the hardware with high-speed operation capability mainly executes convolution operation of digital baseband signals and channel impulse responses.
Fig. 2 is a second schematic structural diagram of the radio frequency signal simulator provided by the invention, as shown in fig. 2, the invention adopts the architecture, and by means of the current mainstream hardware technology, the convenient user interaction capability of a general computer and a fading simulator are fully utilized, and the FGPA adopted by the fading simulator can meet the parallel processing capability of real-time simulation of a multipath channel model.
The user control platform is a control center of the radio frequency signal simulation device, and is used for providing media for using, operating and controlling the system for users, integrating relevant components of a user control unit (also called a user processing unit) and executing relevant functions in a user terminal (such as a PC). The user control unit allows a user to control and use other platforms (such as an integrated interference and channel acquisition unit, an ultra-wideband down-converter and the like of the whole radio frequency signal simulation device) related to the radio frequency signal simulation device in a visual mode, and comprehensively monitors the running state information (such as the state information of the working state, the parameter configuration state and the like) of the other platforms.
The user control unit provided by the invention adopts a visual graphical user interface, is simple and clear, is convenient to operate, can be used for displaying effective information including simulation control, parameter configuration and the like, realizes data transmission among different platforms, and monitors the running state of the system.
When the radio frequency signal simulation operation is abnormal, correct use specifications can be indicated to a user through the modes of an alarm output mechanism, accurate positioning problems and the like, so that the precision element and the radio frequency device are protected from being damaged.
The cloud platform loaded with the channel coefficient generation platform is a channel coefficient calculation core of the radio frequency signal simulation device, depends on a high-performance cloud calculation cluster, can be loaded with a high-performance ray tracing engine (which is described in detail in the embodiment below) and the like, and completes the channel coefficient generation work required in the channel simulation process.
The cloud computing cluster is formed by a large number of servers through a huge internet, and the internet can meet the requirements of low delay, high bandwidth, low cost and the like and also meet the point-to-point communication mode among all nodes. The channel coefficient generating unit is deployed by utilizing the advantages of high-performance calculation, mass storage and the like, modeling simulation and channel coefficient calculation and framing are carried out on each server, channel modeling can be carried out from multiple angles of space, time and frequency in the cloud platform, the actual wireless propagation environment can be more accurately simulated, and more accurate channel data can be generated.
The software radio platform is a radio frequency and baseband processing core part of the whole radio frequency signal simulation device, is a physical medium for carrying out channel simulation on input signals, and completes the work of radio frequency signal receiving and transmitting, baseband signal processing and the like. The signal processing unit provides flexible and configurable bottom hardware support for realizing wireless channel simulation, and based on the flexible and configurable bottom hardware support, the signal processing unit is used for self-defining and controlling the signal processing on software, so that the platform supports a wider frequency range and bandwidth, has higher operation speed, higher precision and the like.
When the radio frequency signal simulation device provided by the invention is used for simulating radio frequency signals, the general flow comprises the steps that a user configures required simulation parameters or generates parameter files through a user control platform and controls a software radio platform, channel coefficient generation and data encapsulation are completed in a cloud platform, the channel coefficient generation and data encapsulation are transmitted to the software radio platform through a wireless network, and the software radio platform carries out fading processing on an INPUT signal (INPUT) according to received control information (the cloud platform transmits the control information parameters to the software radio platform through a master controller) and the channel coefficient, and finally, up-converts and OUTPUTs a target radio frequency signal (OUTPUT).
According to the radio frequency signal simulation device provided by the invention, the software radio platform is controlled by configuring simulation parameters through the user control platform, the generation and data encapsulation of channel coefficients are completed in the cloud platform, the fading processing is carried out on input signals through the software radio level platform, the cloud computing and multi-channel radio channel simulation system architecture is used for replacing a large-scale simulation beam forming device by digital operation equivalence, the organic combination of virtual beams, electromagnetic interference and radio channels is realized, the interference aliasing and dynamic propagation characteristics of phased array radar signals in an open environment space can be accurately simulated, and the difficulty of phased array multi-antenna channel simulation is solved.
Fig. 3 is a schematic diagram of hardware principle of a radio frequency signal simulation device provided by the present invention, as an alternative embodiment, as shown in fig. 3, in the radio frequency signal simulation device provided by the present invention, a signal processing unit includes a radio frequency baseband conversion module, a fading simulator, and a baseband radio frequency conversion module, where the radio frequency baseband conversion module includes a down converter and an analog-to-digital converter, and the baseband radio frequency conversion module includes a digital-to-analog converter and an up converter;
the down converter mixes the input signal with a local oscillator input signal and outputs an analog baseband signal;
The analog-to-digital converter receives the analog baseband signal and outputs a digital baseband signal;
the fading simulator carries out fading simulation processing on the digital baseband signal and outputs a fading digital baseband signal;
The digital-to-analog converter receives the fading digital baseband signal and outputs a fading analog baseband signal;
The up-converter up-converts the fading analog baseband signal to a target frequency to obtain the target radio frequency signal, wherein the target frequency is the frequency of the target radio frequency signal.
When the radio frequency signal simulation device is used, the radio frequency port is generally directly connected with the terminal equipment and the signal transmitting end, such as a base station or a signal generator, after passing through the fading simulator, so that a radio frequency module with higher performance is required to be connected to the radio frequency port, and the mutual conversion between a signal frequency band and a baseband digital domain is realized.
In order to realize a wide frequency band input range, a down converter is arranged in front of an analog-to-digital converter, and an up converter is arranged behind the analog-to-digital converter, so that the frequency band range of a target radio frequency signal is widened.
The processing mode of the digital intermediate frequency or the zero intermediate frequency can lead the radio frequency circuit to be simpler. The zero intermediate frequency processing mode directly mixes the input signal into an analog baseband signal (also called as baseband IQ signal), the baseband IQ signal is sampled and quantized by a data converter, and then the baseband signal is demodulated and processed by a fading simulator.
In particular, the radio frequency signal simulation device of the present invention aims to simulate a complex electromagnetic environment to test or verify the performance of a communication system. The device realizes the signal processing flow from the radio frequency input to the radio frequency output through a series of modularized hardware components.
The Input signal is an externally received radio frequency signal (RF Input) that is mixed with the local oscillator Input signal to an Intermediate Frequency (IF) analog signal or an analog baseband signal after entering the down converter, which is operated to reduce the frequency of the Input signal for further processing. The Local Oscillator input signal is a clock signal generated by a Local Oscillator (LO).
The analog baseband signal obtained through the down conversion is input to an analog-to-digital converter (ADC) to be converted into a digital baseband signal. The generated digital baseband signal is then sent to a fading simulator (which may be an FPGA chip employing SOC architecture) which is responsible for logic control of the overall signal processing flow, including receiving the digital baseband signal output by the ADC and performing fading simulation processing (e.g., fading simulation, phase shift, multipath effect, etc.) by built-in logic and algorithms. The processed faded digital baseband signal is then sent to a digital-to-analog converter (DAC) to convert it back to a faded analog baseband signal. Finally, the fading analog baseband signal is up-converted to the target radio frequency for transmission through the antenna.
In the following, a specific embodiment is provided, and details of one of the transceiving channels will be described in detail.
Regarding the receive channel, the signal receiving end receives the input signal from an analog front end that is highly sensitive, acceptable for small signals, and then digitizes the input signal into in-phase (I) and quadrature (Q) baseband signals using direct down conversion. The down-converted analog baseband signal is subjected to a high-speed analog-to-digital converter to obtain a digital baseband signal, and the digital baseband signal is transmitted from the vector signal receiver to the fading simulator in a point-to-point (P2P) manner for further processing.
For the transmit channel, the master synthesizes the baseband I/Q signals and transmits the signals to the fading simulator over a standard PCIe connection (DMA). A digital up-converter (DUC) mixes, filters, and interpolates the signal to 400MS/s. The digital-to-analog converter converts the received signal back to an analog signal. The low pass filter is used to reduce noise and high frequency components in the signal. The mixer up-converts the signal to a user-specified radio frequency. The phase-locked loop controls a voltage controlled oscillator for locking the device clock and a Local Oscillator (LO) to the same reference clock. Depending on the frequency, the signal may pass through the direct conversion path or the down conversion path. The transmitting amplifier is used for amplifying signals, and finally the obtained target radio frequency signals are transmitted through the antenna.
The radio frequency signal simulation device provided by the invention has the advantages that the data interaction between channels depends on the full-connection channel simulation technology, and the minimum bandwidth ensured by the full-connection of the channels is the hardware bottleneck of system data storage, online analysis and real-time high-performance calculation. The method can adopt a general software radio technology based on a high-speed bus, and combines a high-throughput optical fiber transmission technology to realize a modularized architecture of a wireless channel simulation system, thereby improving the expansibility and openness of a platform and solving the difficult problems of large bandwidth and full exchange simulation.
Meanwhile, the radio frequency signal simulation device provided by the invention breaks through the digital simulation technology of a large-scale/ultra-large-scale phased array antenna, replaces a large-scale simulation beam forming device with digital operation equivalent, realizes the organic combination of virtual beams, electromagnetic interference and wireless channels, accurately simulates the interference aliasing and dynamic propagation characteristics of phased array radar signals in an open environment space, and solves the difficulty of phased array multi-antenna channel simulation. The high-speed bus-based general software radio technology is adopted, the high-throughput optical fiber transmission technology is combined to realize the modularized architecture of the wireless channel simulation system, the expansibility and the openness of the platform are improved, the difficult problems of large bandwidth and full-exchange simulation are solved, and the customization requirement under the scene is met.
Compared with the current conventional signal simulator, the radio frequency signal simulator provided by the invention also adopts an ultra-large bandwidth frequency conversion technology, and is mainly represented on an upper/lower frequency converter. The up/down converter is a matched module customized for the complex electromagnetic analog instrument, realizes the functions of limiting amplitude, attenuating, filtering, frequency conversion, amplifying and the like of an input signal, integrates a plurality of groups of pre-selection filter groups at an input end, has the characteristics of large dynamic range, strong anti-interference capability, high burning-out resistance and the like, is very suitable for being used as receiving equipment in the complex electromagnetic environment, integrates a low-phase noise local oscillation source inside the complex electromagnetic environment, has the characteristic of quick frequency conversion time and can realize quick full-band scanning.
Based on the foregoing embodiments, as an optional embodiment, in the radio frequency signal simulation apparatus provided by the present invention, an up-converter is used to up-convert the fading analog baseband signal to a target radio frequency signal, and specifically includes:
Mixing the fading simulation baseband signal with a sixth local oscillation signal through a fifth mixing module to obtain a first frequency signal, mixing the IQ baseband signal with the fifth local oscillation signal through an IQ modulation module to obtain a second frequency signal, and synthesizing the first frequency signal and the second frequency signal into a third frequency signal;
Mixing the third frequency signal with a first local oscillation signal through a first mixing module to obtain a fourth frequency signal;
mixing the fourth frequency signal with a second local oscillation signal through a second mixing module to obtain a fifth frequency signal;
the fifth frequency signal is filtered and amplified and then divided into two paths, and one path of the fifth frequency signal is mixed with a third local oscillation signal through a third mixing module to obtain a sixth frequency signal and a seventh frequency signal;
Combining the sixth frequency signal with the other path of fifth frequency signal to obtain an eighth frequency signal;
Dividing the eighth frequency signal into two paths, and mixing one path of the eighth frequency signal with a fourth local oscillation signal through a fourth mixing module to obtain a ninth frequency signal;
And synthesizing the seventh frequency signal, the ninth frequency signal and the other path of eighth frequency signal, and outputting the target radio frequency signal through an attenuator.
Fig. 4 is a schematic diagram of an up converter according to the present invention, where as shown in fig. 4, the third frequency signal is a 4.8GHZ signal, the first local oscillation signal is a 28.4GHZ signal, the fourth frequency signal is a 23.6±2GHZ signal, the second local oscillation signal is a 23.9 to 43.6GHZ signal, and the fifth frequency signal is a 0.3 to 20GHZ signal;
The sixth frequency signal corresponding to the 28GHz signal, the 35.2GHz signal, the 41.6GHz signal and the 48GHz signal included in the third local oscillator signal is a 16-54 GHz signal, and the seventh frequency signal is a 46-54 GHz signal;
the eighth frequency signal is a 0.3-50 GHz signal, the ninth frequency signal is a 50-67 GHz signal, and the target radio frequency signal is a 0.3-67 GHz signal.
Specifically, the up-converter has a main function of converting the baseband IQ signal or the intermediate frequency IF signal into a radio frequency signal of a target frequency band through multiple frequency conversion, and in this embodiment, up-converting the fading analog baseband signal into the target radio frequency signal. The frequency band of the target radio frequency signal is 0.3-67 GHz, the maximum 2GHz signal bandwidth can be realized, the whole frequency band has no breakpoint performance, and the specific implementation steps comprise:
firstly, a fading simulation baseband signal is converted to obtain a first frequency signal of 4.8GHz, which is the starting point of the frequency conversion process and is used for preparing the subsequent mixing with different local oscillation signals. And after the IQ baseband signal and the fifth local oscillation signal are mixed through the IQ modulation module to obtain a second frequency signal, the first frequency signal and the second frequency signal are combined into a third frequency signal.
Then, the third frequency signal obtained by the first frequency signal of 4.8GHz is mixed with the first local oscillation signal of 28.4GHz to obtain a fourth frequency signal of 23.6GHz +/-2 GHz, and the purpose of this step is to raise the frequency of the signals to a higher frequency band so as to carry out subsequent mixing operation.
Then, a fourth frequency signal of 23.6GHz +/-2 GHz and a second local oscillation signal of 23.9-43.6 GHz are mixed to obtain a fifth frequency signal of 0.3-20 GHz, and further adjustment and expansion of the signal frequency are achieved.
Further, the fifth frequency signal of 0.3-20 GHz is filtered and amplified and then is divided into two paths, wherein one path is mixed with a third local oscillation signal, and the frequency points of 28GHz, 35.2GHz, 41.6GHz and 48GHz are mixed to obtain the signal of 16-54 GHz.
The method mainly comprises the steps of mixing 4-12 GHz frequency band signals and 28GHz frequency points in a fifth frequency signal to obtain 16-24 GHz frequency signals, mixing 3.7-15.2 GHz frequency band signals and 35.2GHz frequency points in the fifth frequency signal to obtain 20-31.5 GHz frequency signals, mixing 4.6-14.1 GHz frequency band signals and 41.6GHz frequency points in the fifth frequency signal to obtain 27.5-37 GHz frequency signals, mixing 4-15 GHz frequency band signals and 48GHz frequency points in the fifth frequency signal to obtain 33-44 GHz frequency signals, mixing 4.8-14.8 GHz frequency band signals and 35.2G frequency points in the fifth frequency signal to obtain 40-50 GHz frequency signals, and mixing 4.4-12.4 GHz frequency points and 41.6G frequency points in the fifth frequency signal to obtain 46-54 GHz frequency signals.
The signals are amplified and output after being subjected to segmented filtering (the signals after frequency mixing and filtering), then the signals are mixed with another path of frequency signals of 0.3-20 GHz which are not mixed by a third local oscillation signal, and one path of frequency signals is synthesized through a microwave switch module and is recorded as an eighth frequency signal. Then, the signals are divided into two paths through another microwave switch module, wherein one path of eighth frequency signals of 5.2-22.2 GHz and fourth local oscillation signals of 44.8GHz are mixed to obtain ninth frequency signals of 50-67 GHz.
And finally, combining all the seventh frequency signals, the ninth frequency signals and the other path of signals into an eighth frequency signal fused by a fourth local oscillator signal through a microwave switch module.
Finally, outputting a target radio frequency signal of 0.3-67 GHz through a 90dB attenuator.
As an alternative embodiment, the attenuator may also directly input baseband IQ signals or internally generate IQ signals (optional components), the maximum frequency of the IQ signals is larger than 1000MHz, the IQ signals are directly modulated to 4.8GHz, and then the target radio frequency signals of 0.3-67 GHz are obtained through frequency conversion the same as intermediate frequency input.
In an alternative embodiment, in the radio frequency signal simulation device provided by the invention, the down converter is mainly used for mixing an input signal with a local oscillator input signal to obtain an analog baseband signal, and the specific structure of the radio frequency signal simulation device comprises a first mixing module, a second mixing module, a third mixing module, a fourth mixing module, a microwave switch module, a filter, an amplifying module, an attenuation module, an intermediate frequency module, a reference module, a power supply module, a control module and the like.
The specific down-conversion flow can be expressed as:
After the power of the input signal is enhanced through the attenuator, the input signal is input into a microwave switch module and is divided into a tenth frequency signal, an eleventh frequency signal and a twelfth frequency signal;
mixing the eleventh frequency signal with a fourth local oscillation signal through a fourth mixing module to obtain a thirteenth frequency signal, and combining the thirteenth frequency signal with the twelfth frequency signal to obtain a fourteenth frequency signal;
mixing the tenth frequency signal with a third local oscillation signal through a third mixing module to obtain a fifteenth frequency signal;
mixing the fourteenth frequency signal, the fifteenth frequency signal and a second local oscillation signal through a second mixing module to obtain a sixteenth frequency signal;
Mixing the sixteenth frequency signal with a first local oscillation signal through a first mixing module to obtain a seventeenth frequency signal;
and mixing the seventeenth frequency signal with a fifth local oscillation signal through a fifth mixing module to obtain the analog baseband signal.
Fig. 5 is a schematic diagram of a down converter according to the present invention, as shown in fig. 5, in an alternative embodiment, the local oscillator input signal is a 0.3-67 GHz signal, the tenth frequency signal is a 16-54 GHz signal, the eleventh frequency signal is a 50-67 GHz signal, the twelfth frequency signal is a 0.3-20 GHz signal, the thirteenth frequency signal is a 2-19 GHz signal, the fifteenth frequency signal is a 2-20 GHz signal, the sixteenth frequency signal is a 23.6GHz signal, the seventeenth frequency signal is a 4.8GHz signal, and the analog baseband signal is a 1.2GHz signal.
Specifically, in the embodiment, the main function of the down converter is to convert an input signal of 0.3-67 GHz into an analog baseband signal of 1.2GHz through multiple frequency conversion, wherein the maximum bandwidth is 2GHz, the frequency is stepped by 10Hz, the gain range is 0-45 dB, and the gain is adjusted by 0.1dB.
Firstly, the input signal is passed through an attenuation module, so that the power of the input signal can be enhanced, and the maximum power of the input signal reaches +10dBm.
Then, the signal is divided into three paths through a switch and is marked as a tenth frequency signal, an eleventh frequency signal and a twelfth frequency signal.
One path of twelfth frequency signal of 0.3-20 GHz is amplified and filtered, and the other path of eleventh frequency signal of 50-67 GHz is amplified and filtered as well, and then mixed with tenth local oscillation signal of 48GHz to obtain thirteenth frequency signal of 2-19 GHz.
And the tenth frequency signal of 16-54 GHz is mixed with the third local oscillation signal after passing through the amplifying filter group to obtain the fifteenth frequency signal of 2-20 GHz.
The method comprises the steps of mixing 16-24 GHz frequency band signals and 28GHz to obtain 4-12 GHz intermediate frequency signals, mixing 20-31.5 GHz frequency band signals and 35.2GHz to obtain 3.7-15.2 GHz intermediate frequency signals, mixing 27.5-37 GHz frequency band signals and 41.6GHz to obtain 4.6-14.1 GHz intermediate frequency signals, mixing 33-44 GHz frequency band signals and 48GHz to obtain 4-15 GHz intermediate frequency signals, mixing 40-50 GHz frequency band signals and 35.2GHz to obtain 4.8-14.8 GHz intermediate frequency signals, and mixing 46-54 GHz frequency band signals and 41.6GHz to obtain 4.4-12.4 GHz intermediate frequency signals.
Further, all the intermediate frequency signals are filtered by a filter bank and then mixed with the second local oscillation signals 24.9-43.6 GHz to obtain sixteenth frequency signals of 23.6GHz, the signal bandwidth of the sixteenth frequency signals is 2GHz, and the overlapping bandwidths of all the filters and the frequency segmentation part at the front end are 2GHz. Thus, no discontinuity point exists in the whole frequency band, and the signal bandwidth is ensured to be 2GHz.
Then, the sixteenth frequency signal and the first local oscillator 28.4GHz are mixed to obtain a seventeenth frequency signal of 4.8 GHz.
The seventeenth frequency signal is mixed with the fifth local oscillation signal to obtain the desired 1.2GHz intermediate frequency analog baseband signal.
In the design of the down converter, the invention can adopt a superheterodyne system, and has the advantages of realizing an intermediate frequency filter with narrower relative bandwidth and higher rectangular coefficient on a lower intermediate frequency and effectively filtering stray interference components.
Meanwhile, the frequency synthesis technology can be adopted by the vibration source of the first mixer, the channel selectivity of the frequency converter is increased, the flexible configuration (such as adjustment of receiving frequency band and bandwidth) of a receiving channel can be realized through twice frequency conversion treatment, and a better image frequency rejection ratio can be obtained.
The radio frequency signal simulation device provided by the invention ensures the amplitude-phase consistency of the channel receiving and transmitting channels by the ultra-large bandwidth frequency conversion technology, directly influences key indexes and reliability such as the dynamic range, the anti-interference capability and the like of equipment simulation, and simultaneously, influences the extensive degree of the equipment using scene by the frequency range, thereby being a guarantee foundation of the system hardware performance.
Fig. 6 is a schematic diagram of a local oscillator distribution unit provided by the present invention, as shown in fig. 6, where the local oscillator distribution unit includes a reference source branching module, and a first local oscillator module, a second local oscillator module, a third local oscillator module, a fourth local oscillator module, a fifth local oscillator module, and a sixth local oscillator module;
The reference source branching module controls at least one of the first local oscillation module, the second local oscillation module, the third local oscillation module, the fourth local oscillation module, the fifth local oscillation module and the sixth local oscillation module to output corresponding local oscillation signals according to the input reference signals, wherein the reference signals can be OCXO signals of 10 MHz.
The OCXO signal specifically refers to a signal source generated by a high-precision and high-stability oven controlled crystal oscillator (Oven Controlled Crystal Oscillator, abbreviated as OCXO), and is widely used in various occasions where precise timing and signal synchronization are required.
The main function of the local oscillator distribution unit is to provide a plurality of local oscillators for the frequency conversion channel, provide input and output functions of 10MHz reference and output 1 path of 10MHz.
The internal 10MHz reference selects a high-stability OCXO signal or the internal 10MHz reference selects a high-stability rubidium clock signal, and when the OCXO signal or the rubidium clock used in the internal is used as a 10MHz frequency reference source, the output frequency has extremely high stability and accuracy, and the strict requirements of the system on the frequency stability and accuracy can be met. The stability of the internal reference frequency is less than or equal to +/-10-8, the accuracy of the internal reference frequency is less than or equal to +/-10-7, and the requirements of the system on the stability and accuracy of the frequency are met.
The output phase noise index of 10MHz is less than or equal to-140 dBc/Hz@100Hz, less than or equal to-150 dBc/Hz@1KHz, less than or equal to-155 dBc/Hz@10KHz or less than or equal to-155 dBc/Hz@100KHz, and the index requirement is met. The scheme mainly provides five local oscillators, wherein the first local oscillation frequency is 28.4GHz, the second local oscillation frequency is 23.9-43.6 GHz frequency stepping 10Hz, the third local oscillation frequency is 28GHz, 35.2GHz, 41.6GHz and 48GHz, the fourth local oscillation frequency is 44.8GHz single-point frequency signal, the fifth local oscillation frequency is 4.8GHz single-point frequency signal, and the reference of all local oscillation is 100MHz.
The radio frequency signal simulation device provided by the invention utilizes the local oscillation distribution unit to distribute the local oscillation signals from the generating source to a system of a plurality of receiving or transmitting points. Wherein the local oscillator signals may be generated by one or more local oscillator sources and then transmitted to various desired locations via a distribution network (e.g., cable, fiber, wireless link, etc.).
As an alternative embodiment, the signal processing unit mentioned in the embodiment of the present invention mainly performs fading simulation processing on an input signal according to the channel impulse response coefficient, and outputs a target radio frequency signal, where the signal processing unit includes:
The signal processing unit inputs the channel impulse response coefficients to the fading simulator in the signal processing unit,
The fading simulator carries out fading simulation processing on the digital baseband signal according to the channel impulse response coefficient to obtain a fading digital baseband signal;
the target radio frequency signal is obtained by performing digital-to-analog conversion on the fading digital baseband signal and then performing up-conversion.
Fig. 7 is a schematic diagram of a signal processing unit provided by the present invention, as shown in fig. 7, in the radio frequency signal simulation device provided by the present invention, the main function of the signal processing unit is to set the transceiving characteristic of a radio frequency signal, and perform channel fading processing on a baseband signal to complete implementation of channel simulation, where the unit mainly includes a radio frequency baseband conversion module and a baseband signal processing module. The unit receives both the channel coefficients from the channel coefficient generation unit and the simulation control and parameter configuration data of the user control unit.
The radio frequency baseband conversion module is mainly used for executing control of down-conversion and analog-to-digital conversion of input signals, and finally sending baseband I-path signals and Q-path signals which are mutually orthogonal to the baseband signal processing module for further processing, and after the signals pass through the baseband signal processing module, the signals are subjected to digital-to-analog conversion and up-conversion processing through the baseband radio frequency conversion module and then output through a radio frequency port.
Parameters such as a simulation center frequency point, bandwidth, input/output level and the like are configured by the user control unit, and meanwhile, the radio frequency baseband conversion module, a register and other programmable devices in the baseband radio frequency conversion module and the like are initialized and parameters are configured. In a real-time simulation scenario, the adjustment of the output signal attenuation value can also be achieved by using a fading simulator in the signal processing unit.
As shown in fig. 7, as a core part of the signal processing unit, the baseband signal processing module is responsible for network communication, data analysis and fading function implementation of a channel. The method comprises initializing and controlling the state of a register and other external devices in ARM, receiving the issued data of other platforms, analyzing and processing the received data, such as controlling the simulation process according to simulation control information, correspondingly transmitting the configuration parameters of a radio frequency baseband conversion module to the radio frequency baseband conversion module, converting the data of power parameter information and the like, transmitting the information of channel coefficient, path power adjustment, noise/interference type, frequency period and the like to FPGA, and performing fading simulation on the input baseband IQ signal and adjusting the power of each path. If necessary, the noise and interference signals can be generated correspondingly according to the configured noise/interference parameter information, and the noise and interference signals are linearly superimposed on the fading signals to be used as the final target radio frequency signals obtained by simulation of a certain channel.
As an alternative embodiment, the simulation channel model adopted by the invention can adopt the structure form of one-to-one correspondence of multipath time delay and fading coefficient, and the fading processing form is processed by adopting the same method as TDL.
At 2×2 and the maximum number of multipaths supported in each sub-channelFor example, the channel impulse response matrix of the MIMO system is:
;
Wherein,Representing a transmitting antennaTo receiving antennaThe channel impulse response of the sub-channels in between, the coefficients of each sub-channel have no correlation.
In addition, for discrete channels, it can be expressed as:
;
Wherein the method comprises the steps ofRepresenting the first in the sub-channelThe complex fading coefficients of the strip path,Is the firstAnd (5) a time delay corresponding to the stripe diameter.
From the channel convolution operation, it can be expressed as:
;
Wherein,Corresponding to the signals received by the two receiving antennas;For the signals sent by the two transmitting antennas, corresponding toAnd (3) developing a channel convolution operation formula to obtain each receiving antenna:
;
。
By integrating the formulas, the channel convolution process is a process of multiplying and adding fading coefficients of all paths in the sub-channel and delayed data for the FPGA.
Fig. 8 is a schematic diagram of the fading simulator provided by the present invention, taking a certain sub-channel as an example, and the flow of the fading simulation is shown in fig. 8, where the delay and the fading coefficient of each path are extracted from the channel coefficient issued by the software radio platform, and are respectively given to the delay module and the product module in the fading simulation for processing.
The radio frequency signal simulation device provided by the invention adopts a general software radio technology based on a high-speed bus, combines a high-throughput optical fiber transmission technology to realize a modularized framework of a wireless channel simulation system, improves the expansibility and openness of a platform, solves the difficult problems of large bandwidth and full exchange simulation, and meets the customization requirement under a scene.
As an optional embodiment, the channel coefficient generation platform is deployed at a cloud server, and a ray tracing simulation module is further deployed in the cloud server, wherein a ray tracing three-dimensional model is loaded in the ray tracing simulation module;
the ray tracing three-dimensional model is generated by performing scene modeling through simulating the behaviors of electromagnetic waves with frequency bands and different bandwidths on each propagation path based on an electronic map provided by a drive test file, wherein the propagation process of the electromagnetic waves is equivalent to ray propagation;
Inputting configuration parameters received through a basic configuration interface, a map configuration interface, an antenna configuration interface, a cell configuration interface and a simulation calculation interface into the ray tracing three-dimensional model to obtain a path loss file output by the ray tracing three-dimensional model;
The path loss file at least comprises a channel impulse response matrix, and the channel impulse response matrix comprises channel impulse response coefficients of all sub-channels.
The wave propagation deterministic model is a formula derived from the Maxwell's equation set on the basis of strict electromagnetic theory. The wave propagation characteristics on the propagation path can be obtained by solving these equations based on the initial conditions and boundary conditions of the wave propagation. The initial conditions are generally relatively fixed as determined by the source, while the boundary conditions are determined by the shape and electromagnetic properties of the interface between the propagation medium and the earth's surface, and generally vary with the propagation environment.
The invention considers that when the wave with high frequency, that is, short wavelength (the wavelength is far less than the spatial variation of the medium and the minimum linear degree of the scatterer) propagates in isotropic and non-uniform medium (such as air), the wave propagation process can be equivalent to the reflection path, scattering path and diffraction path formed by a discrete ray (straight line) on the plane interface.
Therefore, the invention adopts the method of radiowave radioscopy to realize ray tracing, and the abstract wave propagation is equivalent to visual rays, so that various propagation paths of electromagnetic waves, such as direct irradiation, reflection, diffraction, transmission and the like, and various factors influencing the wave propagation are accurately considered, and the propagation mechanism and multipath channel characteristics unique to the complex environment are accurately and efficiently represented for different specific scenes. The multi-mode simulation data intelligent technology based on the geographic information system (Geographic Information System, GIS) and the building information model (Building Information Modeling, BIM) and the complex material parameter library comprises automatic acquisition and loading of simulation formats of GIS data, light weight of building information model data, simulation format conversion and the like. The method mainly comprises the steps of constructing three-dimensional space data with proper precision, namely height information (Heights), clutter information/barriers (Clutter), building Raster data (Building Vector), building Vector data (Building Vector), vector data (Vector), text information (Text) and the like, automatically cleaning irrelevant, invalid and redundant non-associated data by a system, automatically intercepting key contents such as cross sections, surfaces and the like related to simulation calculation in Building information model data, and carrying out electromagnetic parameter assignment. Processing GLTF, IFC, 3D TILE, OBJ and the like, and providing generalized application capability and accurate data base for ray tracing.
By adopting the change, accurate channel information such as power, time delay, angle, polarization and the like can be provided, and the method is suitable for simulation, prediction and modeling of time-varying multi-antenna channels in different frequency bands.
As an alternative embodiment, the radio frequency signal simulation device provided by the invention comprises a ray tracking simulation module which can be used for a typical wireless communication scene, wherein an outdoor scene supports the simulation of urban, suburban and mountain relief topography.
FIG. 9 is a schematic diagram of a design principle of a ray tracing simulation module provided by the present invention, and as shown in FIG. 9, the present invention provides an execution flow of the ray tracing simulation module, which mainly includes, but is not limited to:
And importing a PLANET electronic map from an interface, converting the PLANET electronic map into a structural body definition of ray tracking identification, supporting multi-frequency point simulation of all frequency bands below 6GHz and different bandwidths, and supporting direct irradiation, fresnel reflection, deygout diffraction, outdoor-to-outdoor (Outdoor to Outdoor, O2O) transmission, outdoor-to-indoor (Outdoor to Indoor, O2I) transmission, ground object loss and self-loss models.
For different types of antennas, wherein the 2D antenna is represented by the directional gain of the HV plane, the 3D model can be restored based on the interpolation formula specified by the antenna provider or the enterprise standard, and the 3D antenna is represented by a two-dimensional array, and can be directly used without interpolation reconstruction.
The user can modify and edit parameters of all propagation models according to own requirements, including dielectric constant, diffraction coefficient, outdoor-to-indoor penetration loss coefficient, ground feature loss and self-loss model parameters, and can adaptively switch the propagation models and parameters thereof. The propagation model switch is judged in a combined mode according to the environmental characteristics of the ground objects around the cell, such as building density, change intensity of the ground, base station height, user height and the like, and comprises all the model switches, reflection times and the like.
The program executed by the ray tracing simulation module is mainly divided into a ray tracing model simulation part and a correction part. The simulation part has five main types of interfaces including basic configuration interface, map configuration interface, antenna configuration interface, cell configuration interface and simulation calculation interface, and the correction part has four main types including map configuration interface, data input interface, correction result output interface and basic configuration interface. Each interface uses standardized interface integration, loading and calling.
The radio frequency signal simulation device provided by the invention has the advantages that the high-performance ray tracking simulation technology directly influences the richness of the simulation library in a special environment, the accuracy of an electromagnetic wave propagation path can be improved, and the accuracy and the high efficiency of a specific scene can be effectively represented.
Based on the foregoing embodiments, as an optional embodiment, the radio frequency signal simulation device provided by the present invention further includes an integrated interference and channel acquisition unit;
The integrated interference and channel acquisition unit acquires digital baseband signals in the generation process of the target radio frequency signals, and marks a time stamp and a position stamp for each digital baseband signal;
And storing the digital baseband signals marked with the time stamp and the position stamp into a disk array.
The integrated interference and channel acquisition unit provided by the invention can realize the integration of acquisition, storage, extraction and modeling of wireless interference and channel propagation characteristics in a complex electromagnetic environment.
Based on the stored data, the interference signals are extracted by adopting advanced signal processing technology, including but not limited to using a noise elimination method based on a neural network, so that background noise is effectively inhibited, and the characteristics of the interference signals are highlighted.
Meanwhile, clustering is carried out on the signals through a data mining and clustering algorithm so as to capture main signal components in a complex multipath environment. The multi-dimensional joint statistical modeling method based on the signal clusters can accurately model the time-frequency-space characteristics of the signal clusters. The modeling method not only considers the frequency spectrum and time characteristics of the signals, but also considers the spatial distribution characteristics of the signals, so that the signal propagation characteristics in the complex electromagnetic environment can be described more accurately.
Random fast-varying scenes and signal incoming wave identification of support vector classification (Support Vector Classification, SVC) and support vector regression (Support Vector Regression, SVR) are adopted to realize real-time identification accuracy of more than 99% of various typical propagation scenes and millisecond-level signal incoming wave direction and spatial dispersion degree estimation. The method can meet the requirements of complex electromagnetic environment hybrid transmission links such as missile-borne, airborne, carrier-borne, aerospace, field, sea and the like on accurate characterization of wireless interference and signal propagation characteristics.
Fig. 10 is a schematic diagram of a system principle of the complex electromagnetic simulator provided by the invention, as shown in fig. 10, the invention is based on the integrated interference and channel acquisition technology realized by the integrated interference and channel acquisition unit, can effectively save channel characteristics, reduce error influence caused by split equipment through high-integration integrated acquisition, improve signal fidelity, improve signal cluster multidimensional joint modeling precision, and improve accuracy of time-frequency-space characteristics of a modeling signal cluster.
As an optional embodiment, the radio frequency signal simulation device captures a digital baseband signal with a certain length and sends the digital baseband signal to the channel coefficient generation platform when acquiring the digital baseband signal in the target radio frequency signal generation process, so that the channel coefficient generation platform performs spectrum power analysis and channel parameter analysis on the digital baseband signal to obtain an analysis result;
The analysis results include one or more of path loss, shadowing, channel impulse response, channel power delay, channel delay spread, channel doppler shift/spread.
The invention executes complex electromagnetic environment data acquisition and storage through the integrated interference and channel acquisition unit, and mainly comprises a high throughput rate data flow disc and a measurement result monitoring analysis part, wherein the high throughput rate data flow disc is used for carrying out real-time high-capacity flow disc for later offline analysis on acquired data, and the measurement result monitoring analysis part is used for observing the system state in the measurement process to ensure that the acquisition and storage are smoothly and accurately executed.
The high throughput rate data stream disk function mainly comprises the steps of acquiring a digital baseband signal in the generation process of a target radio frequency signal by using an intermediate frequency digitizer, acquiring time information and position information from a global positioning system (Global Positioning System, GPS) module, and storing the time information and the position information as a time stamp and a position stamp of the digital baseband signal.
Fig. 11 is a schematic diagram of an integrated interference and channel acquisition unit according to the present invention, as shown in fig. 11, in measurement, a radio frequency receiver converts a radio frequency signal to a baseband and divides the radio frequency signal into two paths. One path of data (digital baseband signal) is completely streamed to the disk array for real-time storage, so that all data can be processed and analyzed offline. The other path of digital baseband signal is intercepted for a specific length and then transmitted to the main controller for real-time spectrum power analysis and channel parameter analysis for real-time monitoring of the test state.
The measurement result monitoring is mainly used for performing state observation and channel information preliminary analysis of the radio frequency signal simulation device. The method mainly comprises the steps of performing fast Fourier transform (Fast Fourier Transform, FFT) on intercepted digital baseband signals, then performing channel transfer function estimation of a frequency domain with known transmitting signals, and calculating channel impulse response through frequency domain windowing and Fourier inverse transform. Information such as power delay profile (Power Delay Profile, PDP), delay spread, doppler shift/spread of the channel can be obtained through channel impulse response.
Meanwhile, after the signal spectrum power is obtained through FFT, the known transmitting power is utilized to analyze and calculate the channel characteristics such as path loss, shadow fading and the like.
The radio frequency signal simulation device provided by the invention adopts a system architecture combining high-performance cloud platform calculation with real-time multichannel wireless channel simulation, solves the problems of huge amount of actual measurement data storage, online analysis and real-time high-performance calculation, realizes support for actual measurement data playback and ray tracking modeling, and solves the problems of long-time channel and interference simulation of scenes, high-accuracy ray tracking simulation modeling and multi-scene dynamic simulation.
Based on the content of the above embodiment, as an optional embodiment, the user control unit provided by the invention mainly comprises a user UI interface, a system configuration module, a communication interface module, a scene modeling module and a link parameter configuration module.
Fig. 12 is a schematic diagram of a user control unit provided by the present invention, where as shown in fig. 12, a user control unit performs a main task of providing an environment for simulation parameter configuration and process control for a user, sets and uses a simulator in a visual or simple manner, and sends configuration information to a corresponding unit, and the main task includes a user UI interface, a system configuration module, a communication interface module, a scene modeling and link parameter configuration, where the scene modeling and link parameter configuration provide an input channel for supporting a ray tracing channel modeling mode to participate in simulation, and an operation scheme of each module is described as follows:
The user UI interface is used for providing parameter configurable options in the simplest and direct form, prompting error information for input beyond the effective range and displaying whether the configuration is successful or not, providing control configuration functions such as modes, processes and the like, and realizing the operation of the simulator using interface.
The system configuration module is used for defining a parameter content classification mode and a data conversion packet grouping mode, processing the input parameters according to the rule, and dividing the input parameters into two parts of data for packet grouping.
And the communication interface module is used for providing an interaction function with other units in the system, the bottom layer adopts a user datagram protocol (User Datagram Protocol, UDP), and the interface is realized through an encapsulated Windows-based board-level support package (Board Support Package, BSP) interaction module.
Scene modeling is used for building a three-dimensional geometric model of a real scene or a virtual scene, wherein the geometric model is used for covering various information in the scene as much as possible, such as geographic environment characteristics, buildings, related material parameters and the like.
And the link parameter configuration is used for setting information such as antenna parameters, transceiver positions, frequencies, reasonable propagation mechanisms and the like, loading scene information and then generating configuration files.
In summary, the user performs configuration input through the UI interface, sets relevant parameters of the size scale according to the simulation requirement, performs data classification processing in the system configuration module after the configuration is completed, and transmits the data classification processing to the corresponding units (the channel coefficient generating unit and the signal processing unit) through the communication interface module through the network during issuing.
The method comprises the steps of sending multipath information such as multipath sequence numbers, time delay, doppler types, maximum Doppler frequency shift, doppler frequency shift types, periods and other parameters to a channel coefficient generation unit to trigger a calculation task; and sending the information such as the center frequency, the input and output power level, noise, interference, simulation control and the like to a signal processing unit for subsequent processing.
The state of a part of the simulator can be modified while the simulator is running, e.g. to allow modification of the output level, i.e. to control the attenuation value, but for parameters such as the centre frequency, whether noise is added or not, it is required to stop the current simulation first and restart the simulation after the parameters are modified.
In a working mode compatible with a ray tracking channel modeling mode, a channel scene model is finely built by using three-dimensional modeling software in a user control unit, electromagnetic characteristics of each structural body in a scene are described based on an electric wave propagation theory, modeling is performed by using an electromagnetic numerical calculation method to obtain a material model, an electromagnetic field simulation software is used for modeling to obtain a receiving and transmitting antenna model, and the three model files, carrier frequency, bandwidth, transceiver position, propagation mechanism and other information are integrated by using a data processing tool to form a complete simulation configuration file for calculation by a channel coefficient generation unit.
As an alternative embodiment, the user UI interface mainly comprises four parts, namely a toolbar, a simulation editing window, a state display window and a parameter input and display window.
Wherein the toolbar provides three main types of tools:
(1) The file operation tools, such as new creation, opening, storage, saving, etc., are mainly used for managing simulation files.
(2) Simulation editing tools, such as editing, connecting, deleting, etc., are used for editing control of the model in the simulation editing window.
(3) Simulation control tools, such as start, pause, stop, exit, state switch, etc., are used to simulate the control of states and systems. The simulation editing window is used for creating a simulation model to control a simulation mode of radio frequency signal simulation, such as a requirement of a plurality of channels, whether a MIMO mode is started or not, and the like, which are represented by connection modes of an input module, a channel module and an output module. The status display window is used for observing the running status of the equipment in real time, such as whether an alarm exists, whether the FIFO overflows, and an error prompt.
The parameter input and display window is mainly used for inputting and displaying configuration parameters of the radio frequency signal simulation device and comprises four panels, namely simulation setting, input setting, channel setting and output setting, wherein the panel which can be selectively displayed in the simulation editing window is mainly used for controlling whether shadow fading, noise and interference are added or not, and the main parameters comprise center frequency, reference level, input power, channel model, output gain, names of vector signal sources and generators and the like.
In the channel setting panel, in addition to setting general parameters of the channel model such as carrier frequency, sample density, moving speed, etc., it is most important to select a model type and perform corresponding parameter setting. Selectable models include correlation models, file models, tapped Delay Line (TDL) models, WINNER models, and the like.
After the model is selected, clicking an 'edit' button can pop up a corresponding parameter input window, wherein the related model mainly refers to an I-METRA model, and input parameters comprise a related matrix, a related type and the like of an input antenna and an output antenna.
The file model is imported in the form of a channel impulse response matrix file, so that the channel model generated by the third party software can be simulated.
The input parameters of the TDL model mainly comprise the number of paths, time delay of each path, average amplitude, fading type and the like. The fading type is composed of amplitude distribution and Doppler spectrum, the amplitude distribution mainly comprises Rayleigh distribution, rice distribution, logarithmic distribution and the like, and the Doppler spectrum mainly comprises Jakes spectrum, flat spectrum, laplace spectrum, gaussian spectrum and the like.
The input parameters of the WINNER model mainly include the base station, the mobile station position, the antenna height, and the distance between the two.
Fig. 13 is an overall block diagram of the complex electromagnetic simulator provided by the present invention, and finally, in combination with the illustration in fig. 13, the technical effects of the radio frequency signal simulation device provided by the present invention as the application of the complex electromagnetic simulator are comprehensively stated, and mainly expressed in the following aspects:
(1) The intelligent fusion of wireless interference and channel acquisition, storage, analysis and modeling is adopted, so that the problem of lack of electromagnetic environment simulation models is solved.
The current commercial standardized channel simulator is mainly oriented to public mobile communication, and channel simulation is performed by using a standard model of 3gpp, IEEE, ITU and other organizations, and the generation of the standard model depends on a plurality of units in the civil wireless communication industry chain, including the output of results of wireless channel research teams of typical communication equipment manufacturers and various universities and research institutions worldwide. In the field, users of the channel simulator are not channels or even experts of wireless communication, the research on the wireless interference and the channels is less, the research results are not disclosed outside, the difference between scenes and civil communication is large, and therefore the wireless interference and the channel simulation in the scenes lack an accurate available model.
The invention innovatively integrates the collection, storage, analysis and modeling of wireless interference and channels by adopting a general hardware structure and an intelligent algorithm, so that the whole machine delivery is conveniently and easily carried out, a user can finish the measurement of the wireless interference and the channels of a concerned scene and the final parameter extraction modeling in an instrument operation mode without channel research experience, and a channel simulator is quickly implanted to finish the test and evaluation of equipment.
(2) By adopting the air-sky-sea hybrid link, the cross-medium electric wave propagation is accurately modeled, and the problem that the special scene lacks actual measurement data and an accurate model is solved.
The millimeter wave radar detection and wireless communication scenes have larger spans, cover special extreme scenes such as the sky, the airspace and the sea, have large difficulty and high cost in performing field test on the scenes, and have poorer accuracy of the existing theoretical model at present.
Therefore, the invention adopts a mixed channel modeling method of channel dominant component deterministic characterization, multipath component space-time random and flexible clustering, combines the advantages of statistical modeling and deterministic modeling, not only can realize the joint characterization of space-time random, space consistent and frequency dispersion of millimeter wave ultra-wideband channels under a certain scene, but also can be flexibly coupled with multiple antennas to realize fine granularity precise modeling, thereby obtaining accurate models under the scenes of space-earth, space-air, sea-air, land-sea, star-earth and the like.
The technical characteristics can enable researchers to quickly generate a large number of real and reliable wireless channels and interference data under the scene without expensive and complex channel measurement or deep knowledge of ray tracking and millimeter wave propagation, and solve the problem of difficult field actual measurement.
(3) The full-band, full-switching and ultra-large bandwidth virtual phased array real-time simulation solves the problems of complex scene interference types, large simulation bandwidth, large number of array antennas and the like.
In civil scenes, electromagnetic interference is largely avoided due to strict management, so that in civil channel simulation, the interference type only covers typical common frequency, adjacent frequency, intermodulation and the like. However, in the presence, most of the interference is of a type of interference that is artificially generated, including suppression, induction, aiming, frequency sweep, pulse train, amplitude modulation noise, frequency modulation noise, radio frequency noise, comb spectrum, and the like.
Therefore, the invention focuses on interference simulation, utilizes a high-speed backboard bus, can open a high-speed data channel of the FPGA by virtue of the advantages of the X86 CPU in storage, communication and system control, and adopts internal generation and actual measurement data playback modes to complete interference simulation, thereby realizing internal generation and exchange type interference of full frequency bands.
In addition, current advanced radar detection has been extended from hundreds of megabandwidths to hundreds of gigabandwidths, and large-scale phased array technology is adopted to extend antenna array elements to the order of hundreds of thousands, but current commercial channel simulation is difficult to meet the above requirements.
Therefore, the invention solves the difficult problem of ultra-large bandwidth signal processing by utilizing the current latest hardware platform and adopting a multistage pipeline parallel architecture.
The apparatus embodiments described above are merely illustrative, wherein the elements illustrated as separate elements may or may not be physically separate, and the elements shown as elements may or may not be physical elements, may be located in one place, or may be distributed over a plurality of network elements. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art will understand and implement the present invention without undue burden.
From the above description of the embodiments, it will be apparent to those skilled in the art that the embodiments may be implemented by means of software plus necessary general hardware platforms, or of course may be implemented by means of hardware. Based on this understanding, the foregoing technical solution may be embodied essentially or in a part contributing to the prior art in the form of a software product, which may be stored in a computer readable storage medium, such as ROM/RAM, a magnetic disk, an optical disk, etc., including several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the method described in the respective embodiments or some parts of the embodiments.
It should be noted that the above-mentioned embodiments are merely for illustrating the technical solution of the present invention, and not for limiting the same, and although the present invention has been described in detail with reference to the above-mentioned embodiments, it should be understood by those skilled in the art that the technical solution described in the above-mentioned embodiments may be modified or some technical features may be equivalently replaced, and these modifications or substitutions do not make the essence of the corresponding technical solution deviate from the spirit and scope of the technical solution of the embodiments of the present invention.