A matching pattern iterative calibration method for a wireless multipath channel

Abstract

The present application belongs to the technical field of wireless communication, and particularly relates to a matching directional pattern iterative calibration method for a wireless multipath channel. The method comprises the following steps: firstly, initializing a matching directional pattern group; when receiving a pilot signal at a receiving end, using a directional pattern in the matching directional pattern group, changing the directional pattern multiple times within a single pilot symbol duration; then, using a locally stored pilot sequence, estimating equivalent channel parameters when each directional pattern is used, and using the equivalent channel parameters to calculate a directional pattern calibration coefficient; using the directional pattern calibration coefficient to calibrate a receiving directional pattern, obtaining a calibrated directional pattern; selecting a directional pattern closest to the calibrated directional pattern from the receiving end available directional patterns, using the selected directional pattern as a matching directional pattern, and updating the matching directional pattern group. The above steps are repeated multiple times to realize matching directional pattern iterative calibration. The present application adjusts the receiving end directional pattern through iteration, so that the directional pattern matches the current wireless environment, and high-efficiency signal reception is realized.

Description

Technical Field

[0001] This invention belongs to the field of wireless communication technology, and particularly relates to an iterative calibration method for matching antenna patterns to match the current wireless environment and achieve efficient signal reception for wireless multipath channels. Background Technology

[0002] In recent years, people's ever-increasing communication needs have greatly promoted the rapid development of wireless communication technology. From simple voice and text transmission services to new wireless broadband services such as live video streaming and autonomous driving, people's demand for wireless communication speeds is getting higher and higher. Increased communication speeds depend on the development and utilization of wireless channel resources. However, high-quality spectrum resources below 6GHz are gradually being exhausted, making it difficult to continue supporting the ever-increasing capacity demands. By adopting spatial channel technology, simultaneous transmission and reception of wireless signals at the same frequency can be achieved, effectively improving spectrum utilization efficiency. Therefore, this field has become an important development direction for current wireless communication. As the front end of wireless signals, the antenna directly determines the quality of signal transmission and reception. The antenna's response to electromagnetic waves arriving from different directions, including its influence on parameters such as the strength and phase of the incoming signal, is reflected in the antenna's radiation pattern, which is determined by the antenna's structure and materials and is difficult to adjust flexibly. Although some reconfigurable antenna structures exist, radiation pattern adjustment methods mainly focus on adjusting the radiation pattern amplitude parameters, i.e., controlling the energy reception intensity in certain directions. This adjustment method can improve signal reception gain to some extent, but it cannot achieve real-time matching with the electromagnetic environment to achieve efficient signal reception. In addition, existing reconfigurable antenna structures also suffer from problems such as coarse pattern adjustment granularity, inability to match the electromagnetic environment, and low signal reception gain. Summary of the Invention

[0003] The technical problem to be solved by this invention is to overcome the shortcomings of the prior art and propose an iterative calibration method for matching pattern in wireless multipath channels. By using the wireless channel estimation results, the antenna pattern is iteratively adjusted to match the current wireless environment and achieve efficient signal reception.

[0004] To achieve the above objectives, the present invention provides the following technical solution, the overall steps of which are as follows: Figure 1 As shown:

[0005] A matching pattern iterative calibration method for wireless multipath channels includes the following steps:

[0006] Step 1: Initialize the matching direction pattern group;

[0007] Step 2: When receiving the pilot signal, the receiver uses the pattern in the matching pattern group and changes the pattern multiple times within the duration of a single pilot symbol.

[0008] Step 3: The receiver uses the locally stored pilot sequence to estimate the equivalent channel parameters for each radiation pattern.

[0009] Step 4: Calculate the pattern calibration coefficients using equivalent channel parameters;

[0010] Step 5: Use the pattern calibration coefficient to calibrate the pattern used in Step 2 to obtain the calibrated pattern;

[0011] Step 6: Select the radiation pattern that is closest to the calibration radiation pattern in Step 5 from the radiation patterns that can be realized at the receiving end, and update the matching radiation pattern group;

[0012] Step 7: Repeat steps 2 to 6 multiple times to achieve iterative calibration of the matching pattern.

[0013] Preferably, the receiver may be equipped with a single antenna or multiple antennas, and the radiation pattern in the matching pattern group includes the amplitude and phase response of the antenna to signals from different directions.

[0014] Preferably, the antenna equipped at the receiving end in step 2 can be a single antenna or a subarray formed by multiple antennas connected to the same radio frequency channel.

[0015] Preferably, the matching pattern group in step 1 is a set containing one or more patterns.

[0016] Preferably, in step 5, the radiation pattern in step 2 is directly calibrated using the radiation pattern calibration coefficient.

[0017] Preferably, in step 5, the antenna parameters used to form the radiation pattern in step 2 are calibrated using a radiation pattern calibration coefficient.

[0018] Preferably, the antenna parameters that are closest to the antenna parameters corresponding to the calibration pattern in step 5 are selected from the antenna parameters corresponding to the achievable radiation patterns at the receiving end, and the matching pattern group is updated.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] This invention utilizes a variable radiation pattern to sense multipath differences. During signal transmission and reception, it iteratively calibrates antenna parameters through feedback to gradually calibrate the antenna radiation pattern, thereby generating a radiation pattern that matches the current multipath channel. This eliminates the need for radiation pattern fitting and reduces computational overhead. Furthermore, this invention can also indirectly calibrate the antenna radiation pattern by calibrating antenna parameters, making it easy to implement in engineering. Attached Figure Description

[0021] Figure 1 This is a flowchart illustrating the steps of an iterative calibration method for matching pattern in wireless multipath channels according to the present invention.

[0022] Figure 2 This is a schematic diagram of the reconfigurable antenna structure used in an embodiment of the present invention.

[0023] Figure 3 This is a flowchart of the single receiving antenna pattern matching reception scheme of Embodiment 1 of the present invention.

[0024] Figure 4 This is a flowchart of the single receiving antenna configuration parameter matching receiving scheme in Embodiment 2 of the present invention. Detailed Implementation

[0025] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples:

[0026] The following embodiments are based on, Figure 2 The reconfigurable antenna structure shown is implemented using a RIS board, but it is also applicable to other reconfigurable antenna structures. This structure consists of multiple linearly and uniformly arranged adjustable micro-elements, and the radiation pattern of the entire antenna can be adjusted by adjusting the parameters of each micro-element. The receiver can be equipped with a single antenna or multiple antennas; in the embodiments described below, the receiver uses a single-antenna structure. The antenna equipped at the receiver can also be a single antenna or a subarray formed by multiple antennas connected to the same RF channel. In the matching pattern group described in the embodiments below, the radiation pattern includes the amplitude and phase response of the antenna to signals from different directions; the matching pattern group can be a collection containing one or more radiation patterns.

[0027] Example 1

[0028] See Figure 3 This embodiment is one implementation of the matching pattern iterative calibration method for wireless multipath channels according to the present invention. In this embodiment, the receiver uses a single variable pattern antenna, and the matching reception of two streams of incoherent signals is achieved through pattern iterative calibration. The specific steps are as follows:

[0029] Step S101: Initialize the matching direction pattern group It contains K directional patterns in total, and the directional pattern matching the directional pattern group is denoted as K.

[0030] Step S102: The receiver uses a single antenna with a variable pattern for signal reception. When receiving the pilot signal, the antenna uses a matched pattern group. The radiation pattern in the middle, during the duration of a single pilot symbol, sequentially changes from φ1 to φ. K Switch the orientation map. (Note:) The antenna uses a radiation pattern φ K The nth pilot symbol received, h 11 with h 12Let the channels correspond to the two classic transmitters be respectively. Channel estimation can then be performed as follows. The received signal is shown in the following equation:

[0031]

[0032] Where: φ K The k-th radiation pattern used by the antenna. Send signals for the first stream. Send a signal for the second stream.

[0033] Step S103: The receiver uses the locally stored pilot sequence to estimate the equivalent channel parameters for each radiation pattern. The channel estimation algorithm can be a classic algorithm such as LS or MMSE, or other channel estimation algorithms. Utilizing the orthogonality between pilots S1 and S2, the equivalent channel parameter F can be estimated, i.e.

[0034]

[0035] Step S104: Calculate the pattern calibration coefficients using the equivalent channel parameters based on the constraint equations. Make

[0036]

[0037] Where C1 and C2 are the antenna gain for matching the reception of the two streams of signals, and their values ​​are specified according to application requirements. For example, if it is desired that the received two separate streams of signals have the same gain, then C1 = C2 = 1. It is the MP inverse of F;

[0038] Step S105: Calibrate the receiving pattern used in step S102 using the pattern calibration coefficient to obtain the calibrated pattern, i.e.:

[0039]

[0040] in: This is the calibration pattern corresponding to the first flow. This is the calibration pattern corresponding to the second flow.

[0041] Step S106: Select from the antenna's realizable radiation pattern... The closest direction graph is used as the matching direction graph, and the matching direction graph group is updated.

[0042] Step S107: Repeat steps S102-S106 multiple times to achieve iterative calibration of the matching pattern.

[0043] In step S105 of this embodiment, the radiation pattern in step S102 can be directly calibrated using a radiation pattern calibration coefficient, or the antenna parameters used to form the radiation pattern in step S102 can be calibrated. Furthermore, in step S106, a radiation pattern closest to the calibrated radiation pattern can be selected as the matching radiation pattern to update the matching radiation pattern group; or, configurable antenna parameters can be reasonably selected, and the antenna parameters closest to the antenna parameters corresponding to the calibrated radiation pattern in step 5 can be selected from the antenna parameters corresponding to the radiation patterns achievable at the receiving end to update the matching radiation pattern group. Calibrating the antenna radiation pattern indirectly through calibrating antenna parameters is easy to implement in engineering.

[0044] Example 2

[0045] See Figure 4 As shown, this embodiment is another implementation of the matching pattern iterative calibration method for wireless multipath channels according to the present invention. In this embodiment, the receiver uses a single variable pattern antenna, and pattern calibration is completed through iterative calibration of antenna parameters to achieve matched reception of two streams of incoherent signals. The specific steps are as follows:

[0046] Step S201: Initialize the matching direction pattern group It contains K directional patterns in total, and the directional pattern matching the directional pattern group is denoted as K. The antenna element weights corresponding to each radiation pattern are:

[0047] Step S202: When receiving the pilot signal, the antenna adopts a matched pattern group. The radiation pattern in the middle, during the duration of a single pilot symbol, sequentially changes from φ1 to φ. K Switch the orientation map. (Note:) The antenna uses a radiation pattern φ K The nth pilot symbol received, h 11 with h 12 Let the channels correspond to the two classic transmitters be respectively. Channel estimation can then be performed as follows. The received signal is shown in the following equation:

[0048]

[0049] Where: φ K The k-th radiation pattern used by the antenna. Send signals for the first stream. Send a signal for the second stream.

[0050] Step S203: The receiver uses the locally stored pilot sequence to estimate the equivalent channel parameters for each radiation pattern. The channel estimation algorithm can be a classic algorithm such as LS or MMSE, or other channel estimation algorithms. Utilizing the orthogonality between pilots S1 and S2, the equivalent channel parameter F can be estimated, i.e.:

[0051]

[0052] in: This is the calibration pattern corresponding to the first flow. This is the calibration pattern corresponding to the second flow.

[0053] Step S204: Calculate the pattern calibration coefficients using the equivalent channel parameters based on the constraint equations. Make

[0054]

[0055] Where C1 and C2 are the antenna gain for matching the reception of the two streams of signals, and their values ​​are specified according to application requirements. For example, if it is desired that the received two separate streams of signals have the same gain, then C1 = C2 = 1. It is the MP inverse of F;

[0056] Step S205: Use the pattern calibration coefficients to calibrate the antenna element weights corresponding to the received pattern used in step S202, and obtain the calibration weights, i.e.:

[0057]

[0058] in: To correspond to the first-class calibration weights, For the calibration weights corresponding to the second stream, w K To be with φ K The corresponding antenna element weights.

[0059] Step S206: Select and calibrate weights from the configurable antenna element weights. The closest weight is used as the corresponding directional pattern for the matching directional pattern group, and the matching directional pattern group is updated.

[0060] Step S207: Repeat steps S202-S206 multiple times to achieve iterative calibration of the matching pattern.

[0061] The difference between Embodiment 1 and Embodiment 2 of this application is as follows: Embodiment 1 obtains the matching radiation pattern and then uses a fitting method to acquire the antenna element weights corresponding to the radiation pattern before configuring them on the antenna. This method has higher accuracy but requires more computation. Embodiment 2 directly calculates the element weights using the linear transformation relationship between the radiation pattern and the element weights. This method has slightly lower accuracy but requires less computation.

[0062] The above specific implementation methods and embodiments are specific support for the technical idea of ​​the matching pattern iterative calibration method for wireless multipath channels proposed in this invention. They should not be used to limit the scope of protection of this invention. Any equivalent changes or modifications made on the basis of this technical solution in accordance with the technical idea proposed in this invention shall still fall within the scope of protection of this invention.

Claims

1. A method for matched pattern iterative calibration for wireless multipath channels, characterized by: Includes the following steps, Step 1: Initialize the matching direction pattern group; Step 2: When receiving the pilot signal, the receiver uses the pattern in the matching pattern group and changes the pattern multiple times within the duration of a single pilot symbol. Step 3: The receiver uses the locally stored pilot sequence to estimate the equivalent channel parameters for each radiation pattern. Step 4: Calculate the pattern calibration coefficients using equivalent channel parameters; Step 5: Use the pattern calibration coefficient to calibrate the pattern used in Step 2 to obtain the calibrated pattern; Step 6: Select the radiation pattern that is closest to the calibration radiation pattern in Step 5 from the radiation patterns that can be realized at the receiving end, and update the matching radiation pattern group; Step 7: Repeat steps 2 to 6 multiple times to achieve iterative calibration of the matching pattern.

2. The method of claim 1, wherein: The receiver can be equipped with a single antenna or multiple antennas, and the radiation pattern in the matching pattern group includes the amplitude and phase response of the antennas to signals from different directions.

3. The method of claim 1, wherein: In step 2, the antenna equipped at the receiving end can be a single antenna or a subarray formed by multiple antennas connected to the same radio frequency channel.

4. The method of claim 1, wherein: The matching pattern group in step 1 is a set containing one or more patterns.

5. The method of claim 1, wherein: In step 5, the radiation pattern from step 2 is directly calibrated using the radiation pattern calibration coefficient.

6. The matching pattern iterative calibration method for wireless multipath channels according to claim 1, characterized in that: In step 5, the antenna parameters used to form the radiation pattern in step 2 are calibrated using pattern calibration coefficients.

7. The method of claim 1, wherein: Select the antenna parameters that are closest to the antenna parameters corresponding to the calibration pattern in step 5 from the antenna parameters corresponding to the achievable radiation pattern at the receiver, and update the matching pattern group.

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