A non-orthogonal polarized MIMO communication system

Abstract

The application discloses a non-orthogonal polarization MIMO communication system, and belongs to the technical field of wireless communication, which comprises a serial-parallel conversion and precoding module, a signal distribution network, a transmitting channel, a non-orthogonal transmitting array antenna, a non-orthogonal receiving array antenna, a receiving channel, a signal combination network and a MIMO signal detection module, wherein the non-orthogonal transmitting array antenna is provided with non-orthogonal transmitting antenna units, and the non-orthogonal receiving array antenna is provided with non-orthogonal receiving antenna units. The application can realize parallel transmission of multiple signal streams under various channel conditions, and improve the system transmission rate and the spectrum utilization rate.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and more specifically, to a non-orthogonal polarization MIMO communication system. Background Technology

[0002] With the continuous development of communication technology, research focus has gradually expanded from the traditional time-frequency domain to the spatial domain, giving rise to MIMO communication systems that support multi-stream spatial multiplexing. These systems significantly improve system spectrum utilization and have been widely applied in 5G mobile communications. While MIMO communication systems offer many advantages, in line-of-sight communication scenarios, the channel often exhibits Gaussian / quasi-Gaussian characteristics, with strong correlation between received signals, severely limiting spatial multiplexing and making it difficult to support multi-stream parallel transmission. Furthermore, multi-user MIMO communication systems can only improve network capacity between the base station and multiple terminals, failing to address the challenge of transmission rate and spectrum efficiency between the base station and a single terminal being constrained by channel conditions. With the rapid development of future applications such as high-definition video, artificial intelligence (AI), and augmented reality (AR), the massive amounts of data generated place higher demands on the transmission rate of wireless communication systems. Therefore, how to further improve the spectrum utilization of MIMO communication systems has become a research hotspot in recent years.

[0003] Existing technologies cannot effectively support multi-stream spatial multiplexing under conditions of strong channel correlation, making it difficult to further improve the spectral efficiency and transmission rate of MIMO communication systems. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a non-orthogonal polarization MIMO communication system that can realize the parallel transmission of multiple signal streams under various channel conditions, thereby improving the system transmission rate and spectrum utilization.

[0005] The objective of this invention is achieved through the following solution:

[0006] A non-orthogonal polarization MIMO communication system includes: a serial-to-parallel conversion and precoding module, a signal distribution network, a transmission channel, a non-orthogonal transmission array antenna, a non-orthogonal receiving array antenna, a receiving channel, a signal combining network, and a MIMO signal detection module. The non-orthogonal transmission array antenna is provided with a non-orthogonal transmission antenna element, and the non-orthogonal receiving array antenna is provided with a non-orthogonal receiving antenna element.

[0007] At the transmitting end, the baseband signal is processed by the serial-to-parallel conversion and precoding module, then divided into multiple transmit signals by the signal distribution network. After being processed by multiple transmit channels, the signals are transmitted by multiple non-orthogonal transmit antenna elements in the non-orthogonal transmit array antenna. At the receiving end, multiple receive signals are received by multiple non-orthogonal receive antenna elements in the non-orthogonal receive array antenna. After being processed by the receive channel, the multiple receive signals are combined by the signal combining network, and finally processed by the MIMO signal detection module to obtain the received baseband signal.

[0008] Furthermore, each non-orthogonal transmitting antenna element has different polarization characteristics; each non-orthogonal receiving antenna element has different polarization characteristics; each non-orthogonal receiving antenna element simultaneously receives signals transmitted by multiple non-orthogonal transmitting antenna elements with different polarization characteristics.

[0009] Furthermore, the non-orthogonal transmitting array antenna includes at least four non-orthogonal transmitting antenna elements with different polarization characteristics; the non-orthogonal receiving array antenna includes at least four non-orthogonal receiving antenna elements with different polarization characteristics.

[0010] Furthermore, suppose the non-orthogonal transmitting array antenna consists of M non-orthogonal transmitting antenna elements, and the non-orthogonal receiving array antenna consists of N non-orthogonal receiving antenna elements; based on the differences in polarization characteristics, each non-orthogonal transmitting antenna element and each non-orthogonal receiving antenna element have different and independent coupling coefficients, and the following system transmission model is established accordingly:

[0011] ;

[0012] in, For the array antenna to receive signals, For channel transmission matrix, The antenna coupling coefficient matrix is... To transmit signals for the array antenna, For matrix dot product, For matrix multiplication, the antenna coupling coefficient matrix is... Represented as:

[0013] ;

[0014] in, For receiving antenna unit i With transmitting antenna unit j The coupling coefficient between them , ;

[0015] Antenna Coupling Coefficient Matrix The maximum value of the elements in the set is greater than twice the minimum value, i.e., it satisfies:

[0016] ;

[0017] Antenna Coupling Coefficient Matrix The difference between the maximum and minimum values ​​of the elements is greater than half the average of all elements, which satisfies the following condition:

[0018] .

[0019] Furthermore, the transmit power of each non-orthogonal transmit antenna element They are all different.

[0020] Furthermore, the transmission power The calculation process is as follows:

[0021] Calculate the antenna coupling coefficient matrix using the following formula. Sum of coefficients in each column :

[0022] ;

[0023] Calculate using the following formula reciprocal :

[0024] ;

[0025] Calculate using the following formula normalized coefficient :

[0026] ;

[0027] Calculate the transmit power of each non-orthogonal transmit antenna element using the following formula. :

[0028] .

[0029] Furthermore, the polarization of the corresponding antenna elements of the non-orthogonal transmitting array antenna and the non-orthogonal receiving array antenna is non-orthogonal.

[0030] The beneficial effects of this invention include:

[0031] This invention has a high degree of spatial multiplexing, thereby enabling parallel transmission of multiple signal streams, improving the system transmission rate and spectrum utilization, and is particularly suitable for application in line-of-sight MIMO wireless communication systems. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the structure of a non-orthogonal polarization MIMO communication system proposed in an embodiment of the present invention;

[0034] Figure 2 for Figure 1 The flowchart shows the calculation of transmit power for each transmit antenna element in the non-orthogonal transmit array antenna of the MIMO communication system shown.

[0035] Figure 3 for Figure 1 An exemplary implementation block diagram of a nonorthogonal transmit / receive array antenna in the MIMO communication system shown;

[0036] Figure 4 for Figure 1 An exemplary implementation block diagram of a non-orthogonal transmit / receive antenna unit in the MIMO communication system shown;

[0037] Figure 5 for Figure 1 An exemplary implementation block diagram of a non-orthogonal transmit / receive antenna unit in the MIMO communication system shown;

[0038] Figure 6 for Figure 1 An exemplary implementation block diagram of a non-orthogonal transmit / receive antenna unit in the MIMO communication system shown;

[0039] Figure 7 This is a schematic diagram comparing the bit error rate of the MIMO communication system proposed in this embodiment of the invention with that of a conventional MIMO communication system under a line-of-sight Gaussian channel.

[0040] Figure 8 This is a schematic diagram comparing the bit error rate of the MIMO communication system proposed in this embodiment of the invention with that of a conventional MIMO communication system under a Rayleigh channel.

[0041] In the figure, there are serial-to-parallel conversion and precoding module 101, signal distribution network 102, transmission channel 103, non-orthogonal transmission array antenna 104, non-orthogonal transmission antenna element 105, non-orthogonal receiving array antenna 106, non-orthogonal receiving antenna element 107, receiving channel 108, signal combining network 109, and MIMO signal detection module 110. Detailed Implementation

[0042] All features disclosed in all embodiments of this specification, or steps in all methods or processes implied in the disclosure, may be combined and / or extended or replaced in any way, except for mutually exclusive features and / or steps.

[0043] The specific implementation process of this invention is as follows:

[0044] like Figure 1 As shown in the preferred embodiment, the present invention specifically proposes a non-orthogonal polarization MIMO communication system, including a serial-to-parallel conversion and precoding module 101, a signal distribution network 102, a transmit channel 103, a non-orthogonal transmit array antenna 104, a non-orthogonal transmit antenna element 105, a non-orthogonal receive array antenna 106, a non-orthogonal receive antenna element 107, a receive channel 108, a signal combining network 109, and a MIMO signal detection module 110. At the transmitting end, the baseband signal is processed by the serial-to-parallel conversion and precoding module, and then divided into M transmit signals by the signal distribution network. After being processed by the transmit channel through frequency conversion, filtering, amplitude and phase adjustment, and amplification, the signals are transmitted by M non-orthogonal transmit antenna elements in the non-orthogonal transmit array antenna. The signals transmitted by each transmit antenna element are not completely orthogonal. At the receiving end, due to the independence of the antenna coupling coefficient, even if the channel correlation is strong, the N receive signals received by the N non-orthogonal receive antenna elements in the non-orthogonal receive array antenna still show weak correlation. After being processed by the receive channel through amplification, amplitude and phase adjustment, frequency conversion, and filtering, the N receive signals are combined by the signal combining network and finally processed by the MIMO signal detection module to obtain the received baseband signal.

[0045] Unlike conventional dual-polarized or multi-polarized array antennas, each non-orthogonal transmitting antenna element 105 in the non-orthogonal transmitting array antenna 104 of the present invention has different, but not necessarily orthogonal, polarization characteristics; each non-orthogonal receiving antenna element 107 in the non-orthogonal receiving array antenna 106 also has different, but not necessarily orthogonal, polarization characteristics, and each non-orthogonal receiving antenna element 107 can simultaneously receive signals transmitted by multiple non-orthogonal transmitting antenna elements 105 with different polarization characteristics.

[0046] The non-orthogonal transmitting array antenna 104 is composed of M non-orthogonal transmitting antenna elements 105, and the non-orthogonal receiving array antenna 106 is composed of N non-orthogonal receiving antenna elements 107. The non-orthogonal transmitting array antenna 104 includes at least four non-orthogonal transmitting antenna elements 105 with different polarization characteristics, and the non-orthogonal receiving array antenna 106 includes at least four non-orthogonal receiving antenna elements 107 with different polarization characteristics.

[0047] Due to their different polarization characteristics, each non-orthogonal transmitting antenna element 104 and each non-orthogonal receiving antenna element 106 have different and independent coupling coefficients. Based on this, the system transmission model is established as follows:

[0048] ;

[0049] in, For the array antenna to receive signals, For channel transmission matrix, The antenna coupling coefficient matrix is... To transmit signals for the array antenna, For matrix dot product, For matrix multiplication, the antenna coupling coefficient matrix Represented as:

[0050] ;

[0051] in, For receiving antenna unit i With transmitting antenna unit j The coupling coefficient between them , As can be seen from the system transmission model, even if the channel correlation is strong, the multiple received signals still exhibit weak correlation due to the independence of the antenna summing coefficients, thus it can better support multi-stream parallel transmission.

[0052] To further explain, the antenna coupling coefficient matrix The maximum value of the elements in the set must be greater than twice the minimum value, that is, the following must be satisfied:

[0053] ;

[0054] Antenna Coupling Coefficient Matrix The difference between the maximum and minimum values ​​of the elements must be greater than half the average of all elements, that is, the following must be satisfied:

[0055] ;

[0056] By using the above limitations, the correlation between multiple received signals can be reduced.

[0057] like Figure 2 As shown, the transmit power of each transmit antenna element 105 in the non-orthogonal transmit array antenna 104 is... With antenna coupling coefficient matrix Related to improving system power efficiency and transmit power The calculation steps are as follows:

[0058] Step s1: Calculate the antenna coupling coefficient matrix Sum of coefficients in each column :

[0059] ;

[0060] Step s2: Calculate reciprocal :

[0061] ;

[0062] Step s3: Calculate normalized coefficient :

[0063] ;

[0064] Step s4: Calculate the transmit power of each non-orthogonal transmit antenna element. :

[0065] ;

[0066] like Figure 3 As shown, non-orthogonal transmit / receive array antennas can be designed separately or as an integrated transmit / receive design. By employing different polarization methods (linear polarization, circular polarization), different polarization directions (vertical / horizontal polarization, left-hand circular / right-hand circular polarization), different installation angles, different axial ratios, and non-standard polarization, the polarization between each antenna element can be made non-orthogonal, thereby giving each non-orthogonal transmit antenna element and each non-orthogonal receive antenna element different and independent coupling coefficients.

[0067] Furthermore, each non-orthogonal receiving and transmitting antenna element can adopt non-standard polarization methods such as irregular chamfers, feed line / feed point angles other than 90°, and inconsistent multi-point feed amplitudes. This increases the difference between different polarizations, thereby making the coupling coefficients between each non-orthogonal transmitting antenna element and each non-orthogonal receiving antenna element more distinguishable. For example, such as... Figure 4 As shown, a standard chamfered patch antenna element is a square patch with its corners cut along the diagonal direction, while a non-orthogonal chamfered patch antenna element has a chamfer direction that differs from the diagonal direction. For example... Figure 5 As shown, the feed lines in a standard dipole antenna element are perpendicular to each other, while the feed lines in a non-orthogonal dipole antenna element are not perpendicular to each other. Figure 6 As shown, in a standard dual-feed antenna element, the angle between the feed point and the center of the element is 90 degrees. However, in a non-orthogonal dual-feed antenna element, the angle between different feed points and the center of the element is not equal to 90 degrees, or although the angle between different feed points and the center of the element is 90 degrees, the bridge angle is not 90 degrees.

[0068] Because the polarization characteristics of each transmitting and receiving antenna element are different, even under line-of-sight communication conditions, the channel transmission matrix... The elements are highly correlated, but due to the coupling coefficient matrix The independence of each element means that the correlation between each transceiver unit is still relatively weak, and it still has a high degree of spatial multiplexing, thereby realizing the parallel transmission of multiple signal streams, improving the system transmission rate and spectrum utilization, and is particularly suitable for the design, development and production of line-of-sight MIMO wireless communication systems.

[0069] Figure 7 This is a schematic diagram comparing the bit error rate of the MIMO communication system and the conventional MIMO communication system under a line-of-sight Gaussian channel according to an embodiment of the present invention. Figure 8 This diagram illustrates a comparison of the bit error rate (BER) of the MIMO communication system proposed in this invention with that of a conventional MIMO communication system under a Rayleigh channel. Simulation results show that the conventional MIMO communication system exhibits an extremely high BER under a line-of-sight Gaussian channel, rendering it unusable. In contrast, the non-orthogonal polarization MIMO communication system proposed in this invention demonstrates excellent BER performance under a line-of-sight Gaussian channel, and its BER is comparable to that of a conventional MIMO communication system under a non-line-of-sight Rayleigh channel.

[0070] The above description is merely the technical principles and preferred embodiments used in this invention. Those skilled in the art will understand that this invention is not limited to the specific embodiments described herein. Various obvious changes, adjustments, and substitutions can be made by those skilled in the art without departing from the scope of protection of this invention. Therefore, although the invention has been described in detail through the above embodiments, this invention is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the principles and concept of this invention, and the scope of this invention is determined by the scope of the appended claims.

Claims

1. A non-orthogonal polarization MIMO communication system, characterized in that, include: The system includes a serial-to-parallel conversion and precoding module, a signal distribution network, a transmission channel, a non-orthogonal transmission array antenna, a non-orthogonal receiving array antenna, a receiving channel, a signal combining network, and a MIMO signal detection module. The non-orthogonal transmission array antenna is equipped with a non-orthogonal transmission antenna unit, and the non-orthogonal receiving array antenna is equipped with a non-orthogonal receiving antenna unit. At the transmitting end, the baseband signal is processed by the serial-to-parallel conversion and precoding module, and then divided into multiple transmission signals by the signal distribution network. After being processed by multiple transmission channels, the signals are transmitted by multiple non-orthogonal transmission antenna elements in the non-orthogonal transmission array antenna. At the receiving end, multiple non-orthogonal receiving antenna elements in the non-orthogonal receiving array antenna are used to receive multiple received signals. After being processed by the receiving channel, the multiple received signals are combined by the signal combining network, and finally processed by the MIMO signal detection module to obtain the received baseband signal. Suppose that the non-orthogonal transmitting array antenna consists of M non-orthogonal transmitting antenna elements, and the non-orthogonal receiving array antenna consists of N non-orthogonal receiving antenna elements; based on the differences in polarization characteristics, each non-orthogonal transmitting antenna element and each non-orthogonal receiving antenna element have different and independent coupling coefficients, and the following system transmission model is established accordingly: ； in, For the array antenna to receive signals, For channel transmission matrix, The antenna coupling coefficient matrix is... To transmit signals for the array antenna, For matrix dot product, For matrix multiplication, the antenna coupling coefficient matrix is... Represented as: ； in, For receiving antenna unit i With transmitting antenna unit j The coupling coefficient between them , ; Antenna Coupling Coefficient Matrix The maximum value of the elements in the set is greater than twice the minimum value, i.e., it satisfies: ； Antenna Coupling Coefficient Matrix The difference between the maximum and minimum values ​​of the elements is greater than half the average of all elements, which satisfies the following condition: 。 2. The non-orthogonal polarization MIMO communication system according to claim 1, characterized in that, Each non-orthogonal transmitting antenna element has different polarization characteristics; each non-orthogonal receiving antenna element has different polarization characteristics; each non-orthogonal receiving antenna element simultaneously receives signals transmitted by multiple non-orthogonal transmitting antenna elements with different polarization characteristics.

3. The non-orthogonal polarization MIMO communication system according to claim 2, characterized in that, The non-orthogonal transmitting array antenna contains at least four non-orthogonal transmitting antenna elements with different polarization characteristics; the non-orthogonal receiving array antenna contains at least four non-orthogonal receiving antenna elements with different polarization characteristics.

4. The non-orthogonal polarization MIMO communication system according to claim 1, characterized in that, Transmit power of each non-orthogonal transmitting antenna element They are all different.

5. The non-orthogonal polarization MIMO communication system according to claim 4, characterized in that, The transmission power The calculation process is as follows: Calculate the antenna coupling coefficient matrix using the following formula. Sum of coefficients in each column : ； Calculate using the following formula reciprocal : ； Calculate using the following formula normalized coefficients : ； Calculate the transmit power of each non-orthogonal transmit antenna element using the following formula. : 。 6. The non-orthogonal polarization MIMO communication system according to claim 2, characterized in that, The polarization of the corresponding antenna elements in the non-orthogonal transmitting array antenna and the non-orthogonal receiving array antenna is non-orthogonal.

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