Method for increasing component index freedom degree in two-dimensional orthogonal space dimension

Abstract

The invention discloses a method for increasing the degree of freedom of a component index in a two-dimensional orthogonal spatial dimension. The method comprises the following steps of: 1, giving the number of transmitting antennas of a transmitting end of a wireless communication system; step 2, obtaining a zero emission space vector symbol of an emission antenna; step 3, separating a real part space and an imaginary part space in a zero emission vector symbol, and then splicing the real part space and the imaginary part space together; 4, setting the number of modulated component space index vectors; 5, obtaining a calculation formula of the number of bits carrying the component space index information; step 6, activating the position corresponding to the component index number in the zero component index space vector under the assistance of the component index bit number; and step 7, modulating components of the multi-dimensional signal constellation points to obtain a transmitting space vector and a total extra information bit number which can be carried by the transmitting space vector. The number of the transmitting antennas can be any numerical value; according to the invention, the spatial degree of freedom of component modulation in constellation points is expanded, so that the capability of carrying index bit extra information is improved.

Description

Technical Field

[0001] The invention belongs to the field of wireless communication, and in particular is a method for increasing the freedom of component index in two-dimensional orthogonal space dimensions. Background Art

[0002] With the development in the past decade, spatial modulation (Index Modulation, IM) technology has become one of the key technologies for the next generation of wireless communication networks, with the focus on carrying additional information. Initially, in 2008, Mesleh et al. proposed a spatial modulation (SM) scheme that uses the antenna index in the transmitting antenna spatial domain to carry index information log2N t Bit, N t is the number of transmitting antennas. Subsequently, the proposed generalized SM (GSM) scheme uses multiple antenna index combinations to increase the information bits carried by the antenna index. n a is the number of activated antennas. In order to further carry additional information, Cheng et al. proposed an enhanced SM (ESM) scheme by utilizing the combination of multiple signal constellations and the variability of the number of activated antennas. Huang et al. proposed a GSM (GSM-MIM) scheme based on multi-index modulation, an extended spatial index modulation (ESIM), and a signal space design based on multi-dimensional constellation and variable number of activated antennas (SSD-MCVA) scheme. The above-mentioned index modulation techniques are limited to the one-dimensional transmit antenna space domain, which limits the mining of additional information.

[0003] Based on the consideration of component orthogonality in a two-dimensional signal constellation, Mesleh et al. proposed the quadrature spatial modulation (QSM) scheme in 2015. Since the QSM scheme exploits the orthogonal spatial domain of the transmitting antenna, the number of antenna index information bits it carries increases by log2N compared to the SM scheme. t. In this way, the one-dimensional antenna space domain is expanded into the orthogonal antenna space domain, that is, the transmit antenna index space is divided into the component index space of orthogonal and in-phase signal constellation points. Based on the orthogonal component space, by combining the design of the signal constellation with the design of the number of activated antennas in the orthogonal space domain, Huang et al. proposed a three-dimensional signal constellation-assisted orthogonal index modulation (QIM-TDC) scheme and an irregular Euclidean distance constellation design in an orthogonal index modulation system (IED-QIM) scheme to increase the minimum Euclidean distance between transmitted symbols, thereby improving the reliability of wireless communication. In order to further improve the ability to carry additional information, the spatial constellation design (SM-SC) scheme based on spatial modulation is proposed to mine the symbol group index domain by utilizing the combination of symbol "j" and multi-dimensional signal point components. Furthermore, based on the SM-SC scheme, a permutation method is used to develop a permutation index domain based on spatial modulation (JPGA-ISM) jointly designed with permutations, groups and antenna indices. However, in the SM-SC scheme and the JPGA-ISM scheme, the degree of freedom of the component index in the formed spatial symbol is still the range of the number of transmitting antennas. Therefore, the limited freedom of component indexing limits the ability to carry additional information of antenna index bits. Summary of the invention

[0004] The present invention provides a method for increasing the freedom of component index in a two-dimensional orthogonal space dimension. Instead of using an antenna index vector to modulate a signal constellation point, a component index vector is used to modulate a component in a multidimensional constellation point to a specified component index number, thereby expanding the freedom of the component index space in the constellation point to solve the defects in the prior art.

[0005] The present invention is achieved through the following technical solutions:

[0006] A method for increasing the freedom of component indexing in a two-dimensional orthogonal space dimension comprises the following steps:

[0007] Step 1: In a multiple-input multiple-output wireless communication system, the number of transmitting antennas at the transmitting end of the given wireless communication system is N t ; N t ∈Z + And N t ≥2, Z + is a positive integer;

[0008] Step 2: The zero transmission space vector symbol of the transmitting antenna can be expressed as:

[0009] That is, an N t ×1-dimensional complex vector symbol in is the real part of the space vector, is the imaginary part of the space vector;

[0010] Step 3: In order to increase the spatial freedom of each component in the signal constellation point to be modulated at a specified position in the component space, separate the real space and the imaginary space in a zero transmission vector symbol, and then splice the two together to form a 2N t ×1-dimensional zero-component index space vector S0;

[0011] Step 4: Set the modulated N, N<2N t The components of the dimensional signal constellation point s are m1, m2, ..., m N , Z + is a positive integer, α∈{1,…,N}; N components in the constellation point s: m1, m2,…, m N Can modulate at component index 11, 2, ..., 2N t Within the range, each component m β , the component space degrees of freedom of β∈{1,2,…,N} is γ CIM =2N t -N+1, which is equivalent to the free component index position and the position of each component itself;

[0012] Step 5: The expression for the number of bits that can carry component space index information is Right now Component index combination The following combinations are legal, the rest are illegal;

[0013] Step 6: Count the number of bits in the component index With assistance, specify a 2N t ×1-dimensional component index vector V λ , 2N t The positions corresponding to the N component index numbers in the zero component index space vector S0 of ×1 dimension are activated and set to "1", obtaining a specified component position index vector

[0014] Step 7: The specified component position index vector The N components of the constellation point s are assigned to the positions corresponding to the N component index numbers to obtain the space vector S1. Through the splitting and combining operations, the transmission space vector X can be obtained. At this time, the total number of additional information bits that the transmission space vector X can carry is

[0015] In the above method for increasing the degree of freedom of component indexing in a two-dimensional orthogonal space dimension, in the step 2, when the component of the signal constellation point is not modulated onto the activated antenna, the transmitted space vector symbol is a zero space vector, that is, its components are:

[0016] In the above-mentioned method for increasing the component index freedom in a two-dimensional orthogonal space dimension, the calculation formula of the zero component index space vector S0 in step 3 is:

[0017]

[0018] So as to realize the component space index from N t Dimension expansion to 2N t dimension.

[0019] In the above-mentioned method for increasing the freedom of component index in a two-dimensional orthogonal space dimension, in step five Represents the number of component space index combinations, that is, in order to convert 2N t ×1-dimensional zero-component index space vector S0 corresponding to the N component index numbers in the position activation, then possible situations.

[0020] As described above, a method for increasing the freedom of component index in a two-dimensional orthogonal space dimension, the legal The component index combinations form a component index vector set Γ = {V1, ..., V τ}, The dimension of each vector is 2N t ×1.

[0021] In the above-mentioned method for increasing the freedom of component index in a two-dimensional orthogonal space dimension, the space vector in step seven can be expressed as Here i Represents a 2N with 1 at position 1 in row i t ×1-dimensional unit vector.

[0022] In the method for increasing the freedom of component indexing in a two-dimensional orthogonal space dimension as described above, the transmission space vector X acquisition operation in step seven is as follows: after modulating the N components in the signal constellation point s to the specified position in the component space, in order to form a non-zero complex transmission space vector X, the components in the vector S1 are split in half and recombined, that is, its components S1(1), ..., S1(N t ) as the real component space of vector X, S1(N t +1),…,S1(2N t ) component as the imaginary component space of vector X, then the expression of the emission space vector X is:

[0023]

[0024] The advantages of the present invention are as follows: the number of transmitting antennas in the present invention does not need to satisfy the power of 2, the number of transmitting antennas can be any value, and there is no need to limit the number of transmitting antennas, which is easy to use; at the same time, the present invention expands the spatial freedom of modulation of components in constellation points, thereby improving the ability to carry additional information of index bits, which plays a role in improving spectrum utilization; and under the same transmission rate condition, the present invention, compared with the traditional design scheme, further increases the minimum Euclidean distance between two transmitting space vectors, which plays a role in enhancing the reliability of wireless communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0026] Figure 1 is a flow chart of the present invention;

[0027] Figure 2 It is a schematic diagram of the free space components of the real space and the imaginary space of the present invention. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] like Figure 1 As shown, a method for increasing the freedom of component index in a two-dimensional orthogonal space dimension comprises the following steps:

[0030] Step 1: In a multiple-input multiple-output wireless communication system, the number of transmitting antennas at the transmitting end of the given wireless communication system is N t ; N t ∈Z + And N t ≥2, Z + is a positive integer;

[0031] Step 2: The zero transmission space vector symbol of the transmitting antenna can be expressed as:

[0032] That is, an N t ×1-dimensional complex vector symbol in is the real part of the space vector, is the imaginary part of the space vector;

[0033] Step 3: In order to increase the spatial freedom of each component in the signal constellation point to be modulated at a specified position in the component space, separate the real space and the imaginary space in a zero transmission vector symbol, and then splice the two together to form a 2N t ×1-dimensional zero-component index space vector S0;

[0034] Step 4: Set the modulated N, N<2N t The components of the dimensional signal constellation point s are m1, m2, ..., m N , Z + is a positive integer, α∈{1,…,N}; N components in the constellation point s: m1, m2,…, m N Can be modulated on component index 11, 2, ..., 2N t In the range, such as Figure 2 As shown, each component m β , the component space degrees of freedom of β∈{1, 2, …, N} is γ CIM =2N t -N+1, which is equivalent to the free component index position and the position of each component itself;

[0035] Step 5: The expression for the number of bits that can carry component space index information is Right now Component index combination The following combinations are legal, the rest are illegal.

[0036] Step 6: Count the number of bits in the component index With assistance, specify a 2N t ×1-dimensional component index vector V λ , 2N t The positions corresponding to the N component index numbers in the zero component index space vector S0 of ×1 dimension are activated and set to "1", obtaining a specified component position index vector

[0037] Step 7: The specified component position index vector The N components of the constellation point s are assigned to the positions corresponding to the N component index numbers to obtain the space vector S1. Through the splitting and combining operations, the transmission space vector X can be obtained. At this time, the total number of additional information bits that the transmission space vector X can carry is

[0038] Specifically, in step 2 of this embodiment, when the components of the signal constellation point are not modulated onto the activated antenna, the transmitted space vector symbol is a zero space vector, that is, its components are:

[0039] Specifically, Figure 2 As shown, the calculation formula of the zero component index space vector S0 in step three of this embodiment is:

[0040]

[0041] So as to realize the component space index from N t Dimension expansion to 2N t dimension.

[0042] More specifically, in step 5 of this embodiment Represents the number of component space index combinations, that is, in order to convert 2N t ×1-dimensional zero-component index space vector S0 corresponding to the N component index numbers in the position activation, then There are several possible situations. Compared with the traditional spatial modulation technology, the proposed technology has certain advantages in the freedom of component space, and the number of transmitting antennas does not need to meet the power of 2. For example, the QSM scheme not only requires the number of transmitting antennas to meet the power of 2, but also the freedom of component space is only γ QSM =N t ; The component space degrees of freedom of the SM-SC scheme are only γ SM-SC =N t .

[0043] Furthermore, the legal The component index combinations form a component index vector set Γ = {V1, ..., V τ}, The dimension of each vector is 2N t × 1. Compared with the QSM and SM-SC schemes that carry additional information, the proposed design method significantly improves the ability to carry additional information.

[0044] Furthermore, the transmit space vector in step 7 of this embodiment can be expressed as Here i Represents a 2N with 1 at position 1 in row i t ×1-dimensional unit vector.

[0045] Furthermore, the transmission space vector X acquisition operation in step 7 of this embodiment is as follows: after modulating the N components in the signal constellation point s to the specified position in the component space, in order to form a non-zero complex transmission space vector X, the components in the vector S1 are split in half and recombined, that is, its components S1(1), ..., S1(N t ) as the real component space of vector X, S1(N t +1),…,S1(2N t ) component as the imaginary component space of vector X, then the expression of the emission space vector X is:

[0046]

[0047] Example

[0048] Step 1: In a multiple-input multiple-output wireless communication system, the number of transmitting antennas at the transmitting end of the given wireless communication system is N t ; N t ∈Z + And N t ≥2, Z + is a positive integer;

[0049] Step 2: The zero transmission space vector symbol of the transmitting antenna can be expressed as: That is, an N t ×1-dimensional complex vector symbol in is the real part of the space vector, is the imaginary part of the space vector; when no component of the signal constellation point is modulated onto the activated antenna, the transmitted space vector symbol is a zero space vector, that is, its components are:

[0050] Step 3: In order to increase the spatial freedom of each component in the signal constellation point to be modulated at a specified position in the component space, separate the real space and the imaginary space in a zero transmission vector symbol, and then splice the two together to form a 2N t The zero component index space vector S0 of ×1 dimension, the calculation formula of the zero component index space vector S0 is:

[0051]

[0052] So as to realize the component space index from N t Dimension expansion to 2N t dimension.

[0053] Step 4: Set the modulated N, N<2N t The components of the dimensional signal constellation point s are m1, m2, ..., m N , Z+ is a positive integer, α∈{1,…,N}; N components in the constellation point s: m1, m2,…, m N Can be modulated on component index 11, 2, ..., 2N t In the range, such as Figure 1 As shown. Thus, each component m β , the component space degrees of freedom of β∈{1, 2, …, N} is γ CIM =2N t -N+1, which is equivalent to the free component index position and the position of each component itself;

[0054] Step 5: The expression for the number of bits that can carry component space index information is (in Represents the number of component space index combinations, that is, in order to convert 2N t ×1-dimensional zero-component index space vector S0 corresponding to the N component index numbers in the position activation, then possible situations), namely Component index combination The combination is legal, the rest are illegal, and the legal The component index combinations form a component index vector set Γ = {V1, ..., V τ}, The dimension of each vector is 2N t ×1;

[0055] Step 6: Count the number of bits in the component index With assistance, specify a 2N t ×1-dimensional component index vector V λ , 2N t The positions corresponding to the N component index numbers in the zero component index space vector S0 of ×1 dimension are activated and set to "1", obtaining a specified component position index vector

[0056] Step 7: The specified component position index vector By assigning the N components of the constellation point s to the positions corresponding to the N component index numbers, we can get the space vector S1, which is expressed as Here i Represents a 2N with 1 at position 1 in row i t ×1-dimensional unit vector, the transmit space vector X is obtained by: after modulating the N components in the signal constellation point to the specified position in the component space, in order to form a non-zero complex transmit space vector X, the components in vector S1 are split in half and recombined, that is, its components S1(1), ..., S1(N t) as the real component space of vector X, S1(N t +1),…,S1(2N t ) component as the imaginary component space of vector X, then the expression of the emission space vector X is:

[0057]

[0058] The total number of additional information bits that can be carried by transmitting the space vector X at the same time is

[0059] The comparison of the amount of additional information carried by the embodiment and the comparative example with the same number of transmitting antennas and components using the embodiment method and the spatial constellation design (SM-SC) solution based on spatial modulation (i.e., comparative example) is shown in Table 1 (where I AI represents the additional information bit, and N is the number of components in the constellation point of the modulated signal) as shown:

[0060]

[0061] Table 1

[0062] It can be seen from the data in Table 1 that the embodiment of the present invention greatly improves the ability to carry additional information compared with the comparative example, thereby effectively improving the spectrum utilization, that is, improving the transmission rate. For example, the transmission rates of the embodiment of the present invention and the comparative example can be expressed by mathematical formulas as follows: here and is the number of information bits carried by the constellation point, and is the number of additional information bits transmitted. When the same constellation is used, However, since the embodiment of the invention improves the carrying of additional information, R1≥R2.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for increasing the freedom of component indexing in a two-dimensional orthogonal space dimension, characterized in that: The steps include: Step 1: In a wireless communication system, the number of transmitting antennas at the transmitting end of a given wireless communication system is N t ; N t ∈Z + And N t ≥2, Z + is a positive integer; Step 2: The zero transmission space vector symbol of the transmitting antenna can be expressed as: That is, an N t ×1-dimensional complex vector symbol in is the real part of the space vector, is the imaginary part of the space vector; Step 3: Separate the real and imaginary parts of a zero emission vector symbol, and then concatenate them together to form a 2N t ×1-dimensional zero-component index space vector S0; Step 4: Set the modulated N, N<2N t The components of the dimensional signal constellation point s are Z + is a positive integer, α∈{1,…,N}; N components in the constellation point s: m1, m2,…, m N Can be modulated on component index 11, 2, ..., 2N t Within the range, each component m β , the component space degrees of freedom of β∈{1, 2, …, N} is γ CIM =2N t -N+1; Step 5: The expression for the number of bits that can carry component space index information is Right now Component index combination The following combinations are legal, the rest are illegal; Step 6: Count the number of bits in the component index With assistance, specify a 2N t ×1-dimensional component index vector V λ , 2N t The positions corresponding to the N component index numbers in the zero component index space vector S0 of the ×1 dimension are activated and set to "1", obtaining a specified component position index vector Step 7: The specified component position index vector The N components of the constellation point s are assigned to the positions corresponding to the N component index numbers to obtain the space vector S1. Through the splitting and combining operations, the transmission space vector X can be obtained. At the same time, the total number of additional information bits that the transmission space vector X can carry is 2. The method for increasing the degree of freedom of component indexing in a two-dimensional orthogonal space dimension according to claim 1, characterized in that: In the step 2, when the components of the signal constellation points are not modulated onto the activated antenna, the transmitted space vector symbol is a zero space vector, that is, its components are:

3. The method for increasing the degree of freedom of component indexing in a two-dimensional orthogonal space dimension according to claim 1, characterized in that: The calculation formula of the zero component index space vector S0 in step 3 is: The component space index is realized from N t Dimension expansion to 2N t dimension.

4. The method for increasing the degree of freedom of component indexing in a two-dimensional orthogonal space dimension according to claim 1, characterized in that: In step five Represents the number of component space index combinations, that is, in order to convert 2N t ×1-dimensional zero-component index space vector S0 corresponding to the N component index numbers in the position activation, then possible situations.

5. The method for increasing the degree of freedom of component indexing in a two-dimensional orthogonal space dimension according to claim 1, characterized in that: The legal step in step 5 The component index combination forms a component index vector set The dimension of each vector is 2N t ×1.

6. The method for increasing the degree of freedom of component indexing in a two-dimensional orthogonal space dimension according to claim 1, characterized in that: The space vector S1 in step 7 can be expressed as Here i Represents a 2N with 1 at position 1 in row i t ×1-dimensional unit vector.

7. The method for increasing the degree of freedom of component indexing in a two-dimensional orthogonal space dimension according to claim 1, characterized in that: The transmission space vector X acquisition operation in step 7 is as follows: after modulating the N components in the signal constellation point s to the specified position in the component space, in order to form a non-zero complex transmission space vector X, the components in the vector S1 are split in half and recombined, that is, its components S1(1), ..., S1(N t ) as the real component space of vector X, S1(N t +1),…,S1(2N t ) component as the imaginary component space of vector X, then the expression of the emission space vector X is:

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