	US 12,191,967 B2
	Non-uniform beam spatial modulation method and system applicable to multi-antenna communication and sensing integration
Shuaishuai Guo, Jinan (CN); Dingyan Cong, Jinan (CN); and Haixia Zhang, Jinan (CN)
Assigned to SHAN DONG UNIVERSITY, Jinan (CN)
Filed by SHAN DONG UNIVERSITY, Jinan (CN)
Filed on Oct. 25, 2022, as Appl. No. 17/973,351.
Prior Publication US 2023/0327739 A1, Oct. 12, 2023
Int. Cl. H04B 7/0413 (2017.01); H04B 7/0408 (2017.01); H04B 7/06 (2006.01)

CPC H04B 7/06952 (2023.05) [H04B 7/0408 (2013.01); H04B 7/0413 (2013.01)]

2 Claims

1. 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 N_ttransmitting-side antennas and N_rreceiving-side antennas, and a number of data streams to be transmitted is N_s;

at a transmitting side, an information bit sequence b to be sent is divided into two parts: b₁and b₂;

b₁is a spatial modulation portion, which is mapped to a beam matrix F_i∈ custom character

with a dimension of N_t×N_s; the beam matrix F_isatisfies probability distribution p (F=F_i)=p_i; i represents a number of an i-th beam matrix F; p represents a probability distribution; F=F_iindicates that F_iis activated; p_iis a probability that each beam matrix is activated;

b₂is a data modulation portion, which is mapped to a symbol vector s with a dimension of N_s×1; and s satisfies a constraint condition expectation mean

the constructing the communication transmitting signal, once the beam matrix F_iis selected, a vector of the communication transmitting signal is expressed as formula (I):

x=F_is, (I)

in formula (I), a normalized transmitting power satisfies ∥F_i∥_F²=N_s;

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=√ρHF_is+n, (II)

in formula (II), ρ represents an average receiving power; H ∈ custom character

^N^_r^×N^_irepresents 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, . . . , F_K} represents a set of candidate beam matrices, and a size of the set is K; p=[p₁, p₂, . . . , p_K] 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):

in formula (IV), det represents a matrix determinant,

and I_N_{_r}represents a unit matrix with a dimension of N_r×N_r;

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):

in formula (V), F_radrefers to a reference beam matrix with good beam pattern characteristics, which is calculated according to a target area;

the finding the candidate beam matrix custom character

and the beam activation probability distribution p where the spectrum frequency is maximum and the sensing performance is best:

1) For optimization of custom character

, F_iis constructed by solving formula (VI):

in formula (VI), ηrepresents a compromise factor between communication and sensing, and F_comⁱrepresents an ideal beam required for an ith communication;

formula (VI) is simplified to obtain formula (VII):

in formula (VII), there are two auxiliary matrices A=[√ηI_N_{_t}]^Tand B_i=[√η(F_comⁱ)^T, √1−ηF_rad^T]^T;

the least mean square algorithm with relatively low complexity is used to solve formula (VII), as shown in formula (VIII):

F_i=A^†B_i. (VIII)

the solved F_iis multiplied with one normalization factor

thus satisfying a power constraint requirement, that is, the candidate beam matrix custom character

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):

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 custom character

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.