US 12,191,967 B2 · Non-uniform beam spatial modulation method and system applicable to multi-antenna communication and sensing integration

Abstract

A non-uniform beam spatial modulation method and system applicable to multi-antenna communication and sensing integration; the method includes: finding an ISAC beam that satisfies both sensing performance and communication performance, including: constructing a communication transmitting signal; constructing a communication receiving signal; constructing an upper bound of the integrated communication and sensing spectral efficiency of the non-uniform beam spatial modulation; constructing an objective function of the sensing performance; and finding a candidate beam matrix and a beam activation probability distribution where the spectrum frequency is maximum and the sensing performance is best; and finding a spectral efficiency of non-uniform beam spatial modulation by means of the ISAC beam. Under the condition of meeting the same sensing performance requirement, the spectral efficiency of the present invention is higher.

A non-uniform beam spatial modulation method applicable to multi-antenna communication and sensing integration, comprising:

finding an Integrated Sensing and Communication (ISAC) beam that satisfies both sensing performance and communication performance;
and
finding a spectral efficiency of non-uniform beam spatial modulation by using the ISAC beam, and completing the non-uniform beam spatial modulation, wherein
the finding the ISAC beam that satisfies both sensing performance and communication performance comprises:
constructing a communication transmitting signal;
constructing a communication receiving signal;
constructing an upper bound of an integrated communication and a sensing spectral efficiency of the non-uniform beam spatial modulation;
constructing an objective function of the sensing performance;
and finding a candidate beam matrix and a beam activation probability distribution where a spectrum frequency is maximum and the sensing performance is best;
the non-uniform beam spatial modulation method is applicable to a multiple-input multiple-output communication system, the multiple-input multiple-output communication system includes Nt transmitting-side antennas and Nr receiving-side antennas, and a number of data streams to be transmitted is Ns;
at a transmitting side, an information bit sequence b to be sent is divided into two parts:
b1 and b2;
b1 is a spatial modulation portion, which is mapped to a beam matrix Fi ∈ with a dimension of Nt×Ns;
the beam matrix Fi satisfies probability distribution p (F=Fi)=pi;
i represents a number of an i-th beam matrix F;
p represents a probability distribution;
F=Fi indicates that Fi is activated;
pi is a probability that each beam matrix is activated;
b2 is a data modulation portion, which is mapped to a symbol vector s with a dimension of Ns×1;
and s satisfies a constraint condition expectation mean
𝔼
[
ss
H
]
=
1
N
s
⁢
I
N
s
;
the constructing the communication transmitting signal, once the beam matrix Fi is selected, a vector of the communication transmitting signal is expressed as formula (I):
x=Fis, (I)
in formula (I), a normalized transmitting power satisfies ∥Fi∥F2=Ns;
the constructing the communication receiving signal, the communication receiving signal received by a communication receiver through a wireless channel is expressed as formula (II):
y=√{square root over (ρ)}HFis+n, (II)
in formula (II), ρ represents an average receiving power;
H ∈ Nr×Ni represents a channel matrix;
and n represents a noise vector;
the upper bound of the integrated communication and sensing spectral efficiency of non-uniform beam spatial modulation is constructed as a target of the communication performance, wherein
= {F1, F2, . . . , FK} represents a set of candidate beam matrices, and a size of the set is K;
p=[p1, p2, . . . , pK] represents a distribution of activation probabilities of various candidate beam matrices;
and the upper bound of the integrated communication and sensing spectral efficiency of the non-uniform beam spatial modulation is expressed as formula (IV):
ℛ
U
(
ℱ
,
p
)
=
∑
i
=
1
❘
"\[LeftBracketingBar]"
ℱ
❘
"\[RightBracketingBar]"
p
i
(
log
⁢
det
⁢
∑
i
-
log
⁢
p
i
)
,
(
IV
)
in formula (IV), det represents a matrix determinant,
∑
i
=
ρ
N
s
⁢
HF
j
⁢
F
i
H
⁢
H
H
+
I
N
t
;
and INr represents a unit matrix with a dimension of Nr×Nr;
constructing a target function of the sensing performance:
the sensing performance is measured by a desired similarity level, and the objective function of the sensing performance, a similarity level, is defined as formula (V):
ϵ
⁡
(
ℱ
,
p
)
=
𝔼
⁡
(

F
i
-
F
rad

F
2
)
=
∑
i
=
1
K
p
i
⁢

F
i
-
F
rad

F
2
.
(
V
)
in formula (V), Frad refers to a reference beam matrix with good beam pattern characteristics, which is calculated according to a target area;
the finding the candidate beam matrix and the beam activation probability distribution p where the spectrum frequency is maximum and the sensing performance is best:
1) For optimization of , Fi is constructed by solving formula (VI):
min

F
i

F
2
=
N
s
η
⁢

F
i
-
F
com
i

F
2
+
(
1
-
η
)
⁢

F
i
-
F
rad

F
2
,
(
VI
)
in formula (VI), ηrepresents a compromise factor between communication and sensing, and Fcomi represents an ideal beam required for an ith communication;
formula (VI) is simplified to obtain formula (VII):
min

F
i

F
2
=
N
s

AF
i
-
B
i

F
2
,
(
VII
)
in formula (VII), there are two auxiliary matrices A=[√{square root over (η)}INt]T and Bi=[√{square root over (η)}(Fcomi)T, √{square root over (1−η)}FradT]T;
the least mean square algorithm with relatively low complexity is used to solve formula (VII), as shown in formula (VIII):
Fi=A†Bi. (VIII)
the solved Fi is multiplied with one normalization factor
N
s

F
i

F
,
thus satisfying a power constraint requirement, that is, the candidate beam matrix to be found;
2) For a sub-problem of an optimization of p, it is constructed as a Lagrange function, as shown in formula (IX):
ℒ
⁡
(
p
,
μ
)
=
∑
i
=
1
K
p
i
(
log
⁢
det
⁢
Σ
i
-
log
⁢
p
i
)
-
μ
⁡
(
∑
i
=
1
K
p
i
-
1
)
.
(
IX
)
formula (IX) is solved to obtain the beam activation probability distribution p;
the finding the spectral efficiency of non-uniform beam spatial modulation using the ISAC beam, wherein the found candidate beam matrix and beam activation probability distribution p where the spectrum frequency is maximum and the sensing performance is best are substituted into formula (IV) to find the integrated communication and sensing spectral efficiency of the non-uniform beam spatial modulation.

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Non-uniform beam spatial modulation method and system applicable to multi-antenna communication and sensing integration

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Non-uniform beam spatial modulation method and system applicable to multi-antenna communication and sensing integration

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Abstract

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