1. A multipath time delay angle power spectrum measuring method based on a phased array is characterized by comprising the following steps:

building a wireless channel measuring system based on a phased array, and determining a measurable multi-path dynamic range of the wireless channel measuring system;

transmitting and receiving sounding signals directed by different beams through the wireless channel measurement system;

continuously collecting the detection signals in a null packet mode, and extracting directional channel impulse response;

determining a noise component threshold according to the directional channel impulse response, and extracting multipath components MPCs above the noise component threshold by adopting a peak detection method;

time delay domain alignment is carried out on the MPCs in different directions, and a peak value detection method is adopted to determine the angular domain peak values of the MPCs in different directions;

setting side lobe thresholds for the MPCs in different directions according to the angular domain peak values of the MPCs in different directions, and extracting the MPCs in the main lobe direction;

and extracting effective MPCs from the MPCs in the main lobe direction according to the multipath dynamic range to obtain a multipath time delay angle power spectrum.

2. The method of claim 1, wherein the phased array based wireless channel measurement system comprises a transmitting end and a receiving end;

the transmitting end includes: the system comprises a radio frequency signal source, a transmitting phased array antenna and a first synchronization module; the receiving end includes: the system comprises a receiving phased array antenna, a radio frequency module, a data acquisition module, a second synchronization module, a storage module and a data post-processing module;

the radio frequency signal source is used for transmitting a radio frequency signal;

the transmitting phased array antenna is a large-scale antenna array capable of forming narrow beams and is used for transmitting detection signals pointed by different beams;

the first synchronization module is used for providing a frequency reference for the radio frequency signal source by adopting rubidium clock synchronization;

the receiving phased array antenna is a large-scale antenna array capable of forming narrow beams and is used for receiving detection signals pointed by different beams;

the radio frequency module is used for converting the received radio frequency signal into an intermediate frequency signal, and amplifying and filtering the intermediate frequency signal;

the data acquisition module is used for realizing the band-pass sampling of the amplified and filtered intermediate-frequency signals through the analog-digital converter and finishing the acquisition of the intermediate-frequency digital signals;

the second synchronization module is used for providing frequency reference for the radio frequency module and the data acquisition module by adopting rubidium clock synchronization;

the storage module is used for storing the acquired intermediate frequency digital signals;

the post-processing module is used for performing off-line processing on the intermediate-frequency digital signal, and performing down-conversion on the intermediate-frequency signal to a baseband to obtain a baseband signal; and carrying out symbol synchronization on the baseband signal and the known excitation signal to obtain channel frequency response, and then carrying out inverse Fourier transform processing to obtain channel impulse response.

3. The method according to claim 1, wherein the method for determining the dynamic range of the multi-path measurable by the wireless channel measuring system comprises: and respectively calculating the difference value of the main lobe gain and the side lobe gain of the transmitting phased array, receiving the difference value of the main lobe gain and the side lobe gain of the transmitting phased array, and summing the difference values to determine.

4. The method of claim 1, wherein the transmitting and receiving sounding signals with different beam directions by the wireless channel measurement system comprises: the transmitting and receiving phased array of the wireless channel measurement system transmits and receives detection signals pointed by different wave beams in a mode of combining electronic scanning with mechanical rotation, and changes the orientation of the phased array through controlling the pointing of the wave beams and horizontal rotation to realize omnidirectional wave beam scanning.

5. The method of claim 1, wherein the performing of the null-packet continuous acquisition on the sounding signal and extracting the directional channel impulse response comprises: and continuously acquiring data packets from the detection signal, controlling the intermittent storage of the data packets, and empty-acquiring the data packets at the non-storage time, wherein the data length in each packet is set to be integral multiple of the length of a transmission sequence, and extracting the channel impulse response containing the angle information of the departure angle of the transmitting end and the arrival angle of the receiving end.

6. The method of claim 1, wherein determining a noise component threshold based on the directional channel impulse response comprises: the noise component threshold is determined using a static or dynamic threshold method.

7. The method of claim 1, wherein the time-domain aligning the MPCs in different directions comprises: the frame synchronization of the received signals is completed, the frame header of the received signals is searched, a plurality of complete frame symbols are extracted according to the length of a fixed frame by taking the frame header as a reference point, and the frame symbols are arranged according to time.

8. The method of claim 1, wherein the setting of the sidelobe threshold for the MPCs in different directions according to the angular domain peak of the MPCs in different directions to extract the MPCs in the mainlobe direction comprises: and respectively calculating the difference value of the main lobe gain and the side lobe gain of the transmitting phased array, receiving the difference value of the main lobe gain and the side lobe gain of the phased array, determining the set value of a side lobe threshold according to the minimum value of the difference value of the main lobe gain and the side lobe gain, taking multipath below the side lobe threshold as invalid multipath received by the side lobe, and extracting the MPCs in the main lobe direction.

9. The method of claim 1, wherein the multipath time delay angle power spectrum comprises: time delay, power, departure angle information, and arrival angle information of the multipath.

Background

The wireless channel measurement is the most direct means for studying the propagation characteristics of the wireless channel, and the basic principle of the channel measurement is that a transmitter transmits a known excitation signal and a receiver analyzes the influence of the wireless channel on the transmission signal. In channel detection, multipath signals with different time delays and amplitude and phase changes after signal superposition can be observed, and a transmitter and a receiver for channel measurement form a channel measurement system (or a channel detector). The channel detector emits and detects electromagnetic waves transmitted through a channel, and determines channel impulse response or channel frequency response.

For a wireless communication system, spatial domain information of a channel is a key point of research, analysis of spatial domain parameter characteristics of the channel can provide reference for practical application problems such as deployment of a wireless communication network, and an angle domain is an important parameter for representing the spatial domain information. In a massive MIMO system, channel information is expanded from an original time domain, frequency domain, two-dimensional space to a time domain, frequency domain, space domain, three-dimensional space, so that in the study of a large-scale multi-antenna communication system, not only the path loss, time delay and other parameter characteristics of a wireless channel need to be analyzed, but also the statistical characteristics of relevant angles, such as an angle of departure, an angle of arrival, an angle power spectrum and the like, need to be studied. When the electromagnetic wave leaves the antenna array, the propagation direction and the antenna array direction have an angle, which is called as a leaving angle. When the electromagnetic wave reaches the receiving-end antenna array, an included angle formed by the propagation direction and the receiving-end antenna array is called an arrival angle.

At present, most of the research on the characteristics of the channel space domain is to use a directional mechanical rotary horn antenna, a massive parallel antenna array, an antenna array with a switching unit or a virtual antenna array, etc. The defects existing in the above modes are as follows: the directional mechanical rotary horn antenna needs manual rotation, and is time-consuming, labor-consuming and low in efficiency; the large-scale parallel antenna array needs to ensure that all antennas transmit and receive signals simultaneously (in parallel), data acquisition is complex, hardware requirements are high, and equipment is expensive; the antenna array switching unit containing the switching unit has a switching time gap; the virtual antenna array requires moving the antenna position and maintaining a precise spatial structure.

Therefore, there is a need for an angle power spectrum measurement method that can achieve high measurement efficiency and reduce measurement cost.

Disclosure of Invention

The invention provides a multi-path time delay angle power spectrum measuring method based on a phased array, which aims to solve the defects in the prior art.

In order to achieve the purpose, the invention adopts the following technical scheme.

A multipath time delay angle power spectrum measuring method based on a phased array comprises the following steps:

building a wireless channel measuring system based on a phased array, and determining a measurable multi-path dynamic range of the wireless channel measuring system;

transmitting and receiving sounding signals directed by different beams through the wireless channel measurement system;

continuously collecting the detection signals in a null packet mode, and extracting directional channel impulse response;

determining a noise component threshold according to the directional channel impulse response, and extracting multipath components MPCs above the noise component threshold by adopting a peak detection method;

time delay domain alignment is carried out on the MPCs in different directions, and a peak value detection method is adopted to determine the angular domain peak values of the MPCs in different directions;

setting side lobe thresholds for the MPCs in different directions according to the angular domain peak values of the MPCs in different directions, and extracting the MPCs in the main lobe direction;

and extracting effective MPCs from the MPCs in the main lobe direction according to the multipath dynamic range to obtain a multipath time delay angle power spectrum.

Preferably, the phased array based wireless channel measurement system comprises a transmitting end and a receiving end;

the transmitting end includes: the system comprises a radio frequency signal source, a transmitting phased array antenna and a first synchronization module; the receiving end includes: the system comprises a receiving phased array antenna, a radio frequency module, a data acquisition module, a second synchronization module, a storage module and a data post-processing module;

the radio frequency signal source is used for transmitting a radio frequency signal;

the transmitting phased array antenna is a large-scale antenna array capable of forming narrow beams and is used for transmitting detection signals pointed by different beams;

the first synchronization module is used for providing a frequency reference for the radio frequency signal source by adopting rubidium clock synchronization;

the receiving phased array antenna is a large-scale antenna array capable of forming narrow beams and is used for receiving detection signals pointed by different beams;

the radio frequency module is used for converting the received radio frequency signal into an intermediate frequency signal, and amplifying and filtering the intermediate frequency signal;

the data acquisition module is used for realizing the band-pass sampling of the amplified and filtered intermediate-frequency signals through the analog-digital converter and finishing the acquisition of the intermediate-frequency digital signals;

the second synchronization module is used for providing frequency reference for the radio frequency module and the data acquisition module by adopting rubidium clock synchronization;

the storage module is used for storing the acquired intermediate frequency digital signals;

the post-processing module is used for performing off-line processing on the intermediate-frequency digital signal, and performing down-conversion on the intermediate-frequency signal to a baseband to obtain a baseband signal; and carrying out symbol synchronization on the baseband signal and the known excitation signal to obtain channel frequency response, and then carrying out inverse Fourier transform processing to obtain channel impulse response.

Preferably, the method for determining the dynamic range of the multi-path measurable by the wireless channel measuring system comprises the following steps: and respectively calculating the difference value of the main lobe gain and the side lobe gain of the transmitting phased array, receiving the difference value of the main lobe gain and the side lobe gain of the transmitting phased array, and summing the difference values to determine.

Preferably, the transmitting and receiving of the sounding signals with different beam directions by the wireless channel measurement system includes: the transmitting and receiving phased array of the wireless channel measurement system transmits and receives detection signals pointed by different wave beams in a mode of combining electronic scanning with mechanical rotation, and changes the orientation of the phased array through controlling the pointing of the wave beams and horizontal rotation to realize omnidirectional wave beam scanning.

Preferably, the performing null packet continuous acquisition on the sounding signal and extracting directional channel impulse response includes: and continuously acquiring data packets from the detection signal, controlling the intermittent storage of the data packets, and empty-acquiring the data packets at the non-storage time, wherein the data length in each packet is set to be integral multiple of the length of a transmission sequence, and extracting the channel impulse response containing the angle information of the departure angle of the transmitting end and the arrival angle of the receiving end.

Preferably, determining a noise component threshold according to the directional channel impulse response includes: the noise component threshold is determined using a static or dynamic threshold method.

Preferably, the time-delay domain alignment of the MPCs in different directions comprises: the frame synchronization of the received signals is completed, the frame header of the received signals is searched, a plurality of complete frame symbols are extracted according to the length of a fixed frame by taking the frame header as a reference point, and the frame symbols are arranged according to time.

Preferably, the setting of the side lobe threshold for the MPCs in different directions according to the angular domain peak values of the MPCs in different directions, and the extracting of the MPCs in the mainlobe direction, includes: and respectively calculating the difference value of the main lobe gain and the side lobe gain of the transmitting phased array, receiving the difference value of the main lobe gain and the side lobe gain of the phased array, determining the set value of a side lobe threshold according to the minimum value of the difference value of the main lobe gain and the side lobe gain, taking multipath below the side lobe threshold as invalid multipath received by the side lobe, and extracting the MPCs in the main lobe direction.

Preferably, the multipath delay angle power spectrum comprises: time delay, power, departure angle information, and arrival angle information of the multipath.

The technical scheme provided by the multipath time delay angle power spectrum measuring method based on the phased array is that the cost and the complexity are low, the method is suitable for measuring the multipath time delay angle power spectrum of a static scene, and the method has important significance for analyzing and modeling the channel characteristics of a space domain.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a flowchart of a multipath delay angle power spectrum measurement method based on a phased array according to an embodiment;

FIG. 2 is a schematic diagram of a wireless channel measurement system based on a phased array according to the present embodiment;

FIG. 3 is a schematic diagram of the operation flow of controlling beam pointing during actual measurement;

FIG. 4 is a diagram illustrating the measurement results of the 10 m anechoic chamber scene according to the first embodiment;

fig. 5 is a schematic diagram of a measurement result of an actual indoor environment scene according to example two.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, but do not preclude the presence or addition of one or more other features, integers, steps, operations, or groups thereof. It should be understood that the term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.

It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

For the convenience of understanding of the embodiments of the present invention, the following description will be further explained by taking specific embodiments as examples with reference to the drawings, which are not intended to limit the embodiments of the present invention.

Examples

Fig. 1 is a flowchart of a multipath delay angle power spectrum measurement method based on a phased array according to this embodiment, and with reference to fig. 1, the method includes:

s1, a wireless channel measuring system based on a phased array is set up, and the measurable multi-path dynamic range of the wireless channel measuring system is determined.

Fig. 2 is a schematic diagram of a wireless channel measurement system based on a phased array according to the present embodiment, and referring to fig. 2, the wireless channel measurement system based on a phased array includes a transmitting end and a receiving end.

The transmitting end includes: the system comprises a radio frequency signal source, a transmitting phased array antenna and a first synchronization module; the receiving end includes: the device comprises a receiving phased array antenna, a radio frequency module, a data acquisition module, a second synchronization module, a storage module and a data post-processing module.

And the radio frequency signal source is used for transmitting radio frequency signals.

The transmitting phased array antenna is a large-scale antenna array capable of forming narrow beams and is used for transmitting detection signals pointed by different beams.

A first synchronization module configured to provide a frequency reference for the RF signal source using rubidium clock synchronization.

The receiving phased array antenna is a large-scale antenna array capable of forming narrow beams and is used for receiving detection signals pointed by different beams.

And the radio frequency module is used for converting the received radio frequency signal into an intermediate frequency signal, and amplifying and filtering the intermediate frequency signal. The radio frequency module adopts a fixed Gain mode instead of an Automatic Gain Control (AGC) mode, and can adjust the Gain through software Control.

The radio frequency module converts radio frequency signals into intermediate frequency signals through a Low Noise Amplifier (LNA), a Band-Pass Filter (BPF) and a down converter, adopts a fixed gain mode, and then the data acquisition module completes the Band-Pass sampling of the amplified and filtered intermediate frequency signals through an ADC and stores the intermediate frequency signals to a hard disk.

And the data acquisition module is used for realizing the band-pass sampling of the intermediate frequency signal through an Analog to Digital Converter (ADC) and finishing the acquisition of the intermediate frequency Digital signal. The sampling rate of the data acquisition module is calculated by a band-pass sampling theorem, the signal recovery can be finished without distortion only if the band-pass sampling theorem is satisfied, and according to the band-pass sampling theorem, if the sampling rate is f_sThen, the following formula (1) is satisfied:

wherein m is an integer and m is less than or equal to f_L/(f_H-f_L) N is an integer, and N is less than or equal to f_H/(f_H-f_L)，f_HAnd f_LThe lowest frequency and the highest frequency of the signal are respectively used, and the sampling frequency f satisfying the formula (1) is used_sAfter sampling at equal intervals, the original signal can be restored without distortion through spectrum shift. Illustratively, f for a central frequency point₀180MHz, bandwidth B100 MHz, intermediate frequency signal, sampling rate f of data acquisition module_s＝500MHz。

And the second synchronization module is used for adopting rubidium clock synchronization to provide frequency reference for the radio frequency module and the data acquisition module.

The storage module is used for storing the acquired intermediate frequency digital signals; the minimum storage rate of the storage hard disk is required to be greater than the data acquisition rate of the data acquisition module so as to meet the requirement of continuous data storage.

The post-processing module is used for performing off-line processing on the intermediate-frequency digital signal, and performing down-conversion on the intermediate-frequency signal to a baseband to obtain a baseband signal; and carrying out symbol synchronization on the baseband signal and the known excitation signal to obtain channel frequency response, and then carrying out inverse Fourier transform processing to obtain channel impulse response.

Obtaining a baseband signal through a DDC and an LPF; symbol synchronization is carried out on baseband signals, frame headers are searched, the baseband signals are received and recorded as Y (f), local multi-carrier excitation signals are recorded as X (f), and the conjugation of the excitation signals is recorded as X^*(f) (ii) a The channel frequency response is obtained by a frequency domain calculation of the conjugate of the received baseband signal and the local excitation signal of equation (2) below:

the phased array is a large-scale antenna array, and narrow beams are formed by utilizing mutual superposition of signal power and mutual interference of phases between array elements.

The method for determining the measurable multi-path dynamic range of the wireless channel measurement system comprises the following steps: and respectively calculating the difference value of the main lobe gain and the side lobe gain of the transmitting phased array, receiving the difference value of the main lobe gain and the side lobe gain of the transmitting phased array, and summing the difference values to determine.

S2 transmitting and receiving probe signals directed by different beams through the wireless channel measurement system.

The transmitting and receiving phased array of the wireless channel measurement system transmits and receives detection signals pointed by different wave beams in a mode of combining electronic scanning with mechanical rotation, and changes the orientation of the phased array by controlling the pointing of the wave beams and horizontally rotating so as to realize equally-spaced omnidirectional wave beam scanning. The method can directly cover a 90-degree sector, and can realize the acquisition of 360-degree channel impulse response by physically turning the phased array to 90 degrees for multiple times during measurement. The operation flow of controlling the beam pointing during actual measurement is shown in fig. 3, and after the 90 ° sector measurement is completed, the phased array is physically turned to 90 °, and the operation in fig. 3 is repeated until the 360 ° channel measurement is completed.

S3, continuously collecting the empty packet of the detection signal, and extracting the directional channel impulse response.

And continuously acquiring data packets for the detection signal, controlling the intermittent storage of the data packets, and empty-acquiring the data packets at the non-storage time, wherein the data length in each packet is set to be integral multiple of the length of a transmission sequence, and extracting the channel impulse response containing the angle information of the departure angle of the transmitting end and the arrival angle of the receiving end. The acquisition mode is continuous acquisition of empty packets and virtual continuous storage, namely continuous acquisition of data packets, and intermittent storage is controlled by a PC.

Specifically, the directional channel impulse response obtained by channel measurement includes n departure angle directions and n arrival angle directions, and n × n directional channel impulse responses are counted, where n depends on the beam scanning interval and the measurement sector angle range.

The beam pointing direction is obtained by the upper computer software, and then the directional channel frequency response can be calculated, as shown in the following formula (3):

the channel impulse response can be obtained from the channel frequency response of the following equation (4) by an inverse fourier transform process.

h(φ_TX,φ_RX,τ)＝FFT^-1(H(φ_TX,φ_RX,f)) (4)

Wherein phi is_TXIndicating transmit phased array beam pointing, phi_RXIndicating the receive phased array beam pointing, phi_TX,φ_RX∈[0,360°]And τ represents multipath delay.

S4, determining the noise component threshold according to the directional channel impulse response, and extracting the Multi-Path Components (MPCs) above the noise component threshold by adopting the peak detection method.

Determining the noise component threshold by adopting a static or dynamic threshold method, and recording asAnd filtering the value of which the power is less than the noise component threshold. And searching the peak value of the value with the power larger than the noise component threshold by adopting a peak value detection method, wherein each peak value is defined as a path, and the peak value is reserved.

S5, time delay domain alignment is carried out on the MPCs in different directions, and peak value detection method is adopted to determine the angular domain peak values of the MPCs in different directions.

The frame synchronization of the received signals is completed, the frame header of the received signals is searched, a plurality of complete frame symbols are extracted according to the length of a fixed frame by taking the frame header as a reference point, and the frame symbols are arranged according to time to complete the time delay domain alignment of the MPCs in different directions.

S6 sets side lobe thresholds for the MPCs in different directions according to the MPCs angle domain peak values in different directions, and extracts the MPCs in the main lobe direction.

In order to eliminate the influence of side lobes subsequently, the directional channel impulse responses acquired by the continuous collection of the null packets all have the same reference time, so that the time delay domains of the directional channel impulse responses can be aligned without further correction.

After time delay domains of the MPCs in different directions are aligned, peak detection is carried out on the MPCs with the same time delay, namely, peak search is carried out on the MPCs with the same time delay and different departure angles and the MPCs with the same arrival angle at first, a peak is reserved, then peak search is carried out again on the MPCs with the same time delay taps and different arrival angles and the same departure angles under the peak, and the peak of an angle domain is reserved to obtain the peak of the angle domain.

Since the narrow beam generated by the phased array has both a main lobe and side lobes, multipath received by the side lobes is considered invalid, i.e., the angular domain peak contains invalid MPCs. And respectively calculating the difference value of the main lobe gain and the side lobe gain of the transmitting phased array, receiving the difference value of the main lobe gain and the side lobe gain of the transmitting phased array, and determining the set value of the side lobe threshold according to the minimum value of the difference value of the main lobe gain and the side lobe gain, wherein the difference value of the main lobe gain and the side lobe gain is recorded as sigma dB. To eliminate the side lobe effect, the strongest peak at each time delay is recorded asThe sidelobe threshold isExtraction of [ Pⁱ _max-σ,Pⁱ _max]MPCs in the main lobe direction within the range.

S7, according to the multipath dynamic range, extracting effective MPCs in the MPCs of the main lobe direction, and obtaining the multipath time delay angle power spectrum.

A multipath delay angle power spectrum comprising: multipath time delay, power, departure angle information and arrival angle information are processed to obtain a multipath power time delay spectrum and an angle power spectrum, and the characteristics of a wireless channel are reflected from three dimensions of a power domain, a time delay domain and an angle domain.

The MPCs in the main lobe direction which are extracted calculate the strongest power which is marked as P_max. Because the transmitting end and the receiving end both adopt phased arrays, the measurable multipath dynamic range of the system obtained in the step S1 is 2 sigma dB, and the power of the MPCs under all time delays is in [ P ]_max-2σ,P_max]The MPCs in the range are reserved as the final effective MPCs, and the multi-path time Delay angle power spectrum is obtained and is marked as PADP (Power Angular Delay Profile).

When the multipath angle is not considered, the Power Delay Profile (PDP) of the omni-directional channel can be obtained by the following equation (5):

when the multipath time delay is not considered, the angle power spectrum is calculated as shown in the following equation (6):

in order to verify the above method, the following two specific examples were performed by using the method in the present embodiment, and the specific parameters of the experiment are as follows:

the phased array uses a 16 x 4 massive antenna array, i.e., four rows and sixteen columns, with the phased array transmit/receive beam main lobe being at least 10dB stronger than the side lobes. The central frequency point of the measuring channel is 3.35GHz, the bandwidth is 100MHz, the 90-degree sector is measured, the scanning interval is 5 degrees, and the total 19 multiplied by 19 is 361 direction channel impulse response. The noise threshold is determined by a static threshold method,take a value 25dB below the maximum power.

Calculation example one, 10 m method anechoic chamber measurement verification

The measurement verification of a specific scene is carried out in a 10 m method anechoic chamber, and in order to highlight the particularity of the scene, reflectors are arranged during the measurement, and the arrangement positions of the reflectors and the phased array are shown in fig. 4- (a). Fig. 4- (b) is a multipath time delay angle power spectrum, and the effective multipath finally extracted appears when the departure angle is 20 °, the arrival angle is-35 °, the stronger reflection path appears when the departure angle is-5 °, the arrival angle is 20 °, the time delay is 10ns, the propagation distance difference is 3m, and a metal reflector exists at the position and is matched with the distribution of a scene reflector.

Example two, actual indoor environmental scene measurement

In an actual indoor environment, the phased array is oriented as shown in fig. 5- (a), and when the transmitting beam is directed at 5 ° and the receiving beam is directed at-5 °, the phased array is in a state where the main beam is directed directly. As shown in fig. 5- (b), the direct path occurs at an angle of departure of 5 ° and an angle of arrival of-5 °, the path has the strongest power, and multipath occurs at angles of departure and arrival of [15 °, -25 ° ], [10 °,0 ° ], [ -5 ° ], [5 °,15 ° ], [40 °,30 ° ], with the highest delay of 20ns, i.e., the maximum difference in multipath distance is 6 m.

In summary, the two experiments verify the practical applicability of the phased array-based multipath delay angle power spectrum measurement method, and by using the advantages of the narrow beam of the phased array, the directional channel impulse response is measured and obtained through beam scanning, noise, beam overlapping and side lobe influence are eliminated, and the multipath delay angle power spectrum is obtained. The method has the advantages of convenience, accuracy, high efficiency and the like, and provides reference for channel space characteristic research and channel modeling of wireless communication.

It will be appreciated by those skilled in the art that the foregoing types of applications are merely exemplary, and that other types of applications, whether presently existing or later to be developed, that may be suitable for use with the embodiments of the present invention, are also intended to be encompassed within the scope of the present invention and are hereby incorporated by reference.

From the above description of the embodiments, it is clear to those skilled in the art that the present invention can be implemented by software plus necessary general hardware platform. Based on such understanding, the technical solutions of the present invention may be embodied in the form of a software product, which may be stored in a storage medium, such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the method according to the embodiments or some parts of the embodiments.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.