generating a sidelink-primary synchronization signal (S-PSS) sequence according to a specific polynomial, and generating an S-PSS synchronization signal according to the S-PSS sequence;

transmitting the S-PSS synchronization signal; wherein, generating the S-PSS sequence according to the specific polynomial comprises one or a combination of following:

generating an S-PSS sequence d_PSS(n) according to a formula d_PSS(n)=1−2x(m), wherein x(m) is generated based on a polynomial x(i+7)=(x(i+4)+x(i))mod 2, m=(n+CS)mod 127, wherein 0≤n<127, n is a first sequence-numbering value, m is a second sequence-numbering value generated from n and CS, i is a third sequence-numbering value, CS is cyclic shift, and CS is a positive integer not equal to 0, 43 and 86; or,

generating an S-PSS sequence d_PSS(n) according to a formula d_PSS(n)=1−2x(m), wherein x(m) is generated based on a polynomial x(i+7)=(x(i+1)+x(i))mod 2, m=(n+CS)mod 127, wherein 0≤n<127, n is a first sequence-numbering value, m is a second sequence-numbering value generated from n and CS, i is a third sequence-numbering value, CS is cyclic shift; or,

generating an S-PSS sequence d_PSS(n) according to a formula d_PSS(n)=d_u(n), wherein

u is a root sequence index, wherein 0≤u<127; or

transmitting the S-PSS synchronization signal on a frequency resource different from a frequency resource occupied by an air-interface downlink-primary synchronization signal (DL-PSS), wherein the air-interface DL-PSS is transmitted by a base station to a terminal, and the S-PSS is transmitted by a terminal to another terminal,

wherein when x(m) is generated based on the polynomial x(i+7)=(x(i+4)+x(i)mod 2, a value of m is taken in one of following ways:

or,

wherein when x(m) is generated based on the polynomial x(i+7)=(x(i+1)+x(i))mod 2, a value of m is taken in one of following ways:

m=(n+43×N_ID⁽²⁾+d1)mod 127, CS=43×N_ID⁽²⁾+d1, wherein N_ID⁽²⁾ is an index value of the S-PSS sequence, d1 is a positive integer; or,

m=(n+(43+d2)×N_ID⁽²⁾+d3)mod 127, CS=(43+d2)×N_ID⁽²⁾+d3, wherein N_ID⁽²⁾ is an index value of the S-PSS sequence, both d2 and d3 are positive integers; or,

m=(n+(43−d4)×N_ID⁽²⁾+d5)mod 127, CS=(43−d4)×N_ID⁽²⁾+d5, wherein N_ID⁽²⁾ is an index value of the S-PSS sequence, both d4 and d5 are positive integers; or,

m=(n+43×(N_ID⁽²⁾+d6))mod 127, CS=43×(N_ID⁽²⁾+d6), wherein N_ID⁽²⁾ is an index value of the S-PSS sequence, d6 is a positive integer; or,

m=(n+43×{N1,N2})mod 127, CS=43×{N1,N2}, wherein N1 and N2 correspond to two index values N_ID⁽²⁾ of the S-PSS sequence, and N1 and N2 correspond to two cyclic shifts of an m-sequence employed for the sidelink-primary synchronization signal; or,

m=(n+X1)mod 127, CS={X1}, wherein X1 corresponds to an index value N_ID⁽²⁾ of the S-PSS sequence, and X1 corresponds to a cyclic shift of an m-sequence employed for the sidelink-primary synchronization signal; or,

m=(n+{X2,X3})mod 127, CS={X2,X3}, wherein X2 and X3 correspond to two index values N_ID⁽²⁾ of the S-PSS sequence, respectively, and X2 and X3 correspond to two cyclic shifts of an m-sequence employed for the sidelink-primary synchronization signal, respectively; or,

m=(n+{X4,X5,X6})mod 127, CS={X4,X5,X6}, wherein X4, X5 and X6 correspond to three index values N_ID⁽²⁾ of the S-PSS sequence, respectively, and X4, X5 and X6 correspond to three cyclic shifts of an m-sequence employed for the S-PSS, respectively; or,

m=(n+d6×N_ID⁽²⁾)mod 127, CS=d6×N_ID⁽²⁾, wherein N_ID⁽²⁾ is an index value of the S-PSS sequence, d6 is a positive integer.