Techniques for synchronization in wireless communications
This application discloses a synchronization signal sending method and a related device. The method includes: generating, a first synchronization signal sequence and a second synchronization signal sequence, where the first synchronization signal sequence is a sequence obtained based on a first m-sequence, the second synchronization signal sequence is a sequence obtained based on a Gold sequence, the Gold sequence is generated based on a second m-sequence and a third m-sequence, and a generator polynomial of the first m-sequence is the same as a generator polynomial of the second m-sequence; mapping, the first synchronization signal sequence onto M subcarriers in a first time unit to obtain a first synchronization signal, and mapping the second synchronization signal sequence onto M subcarriers in a second time unit to obtain a second synchronization signal, where M and N are positive integers greater than 1.
1. An apparatus, comprising:
a processor, configured to generate a primary synchronization signal and a secondary synchronization signal; and
a transceiver, configured to transmit the primary synchronization signal and the secondary synchronization signal;
wherein the primary synchronization signal is based on a primary synchronization signal sequence s(n), and the primary synchronization signal sequence s(n) is based on a sequence c(n), 0≤n≤126, a recursion formula of the sequence c(n) satisfies: c(n+7)=(c(n+4)+c(n))mod 2, and the primary synchronization signal sequence s(n) satisfies one of
s
(
n
)
=
1
-
2
·
c
(
(
n
)
mod
127
)
;
s
(
n
)
=
1
-
2
·
c
(
(
n
+
43
)
mod
127
)
;
or
s
(
n
)
=
1
-
2
·
c
(
(
n
+
86
)
mod
127
)
;
and
wherein the secondary synchronization signal is based on a secondary synchronization signal sequence, and the secondary synchronization signal sequence is based on a sequence f 1 (n) and a sequence f 2 (n), wherein the sequence f 1 (n) has a same recursion formula as the sequence c(n) and a recursion formula of the sequence f 2 (n) satisfies: c(n+7)=(c(n+1)+c(n))mod 2, 127 subcarriers in a first orthogonal frequency division multiplexing (OFDM) symbol are for the primary synchronization signal sequence s(n), and 127 subcarriers in a second OFDM symbol are for the secondary synchronization signal sequence.
2. The apparatus according to claim 1 , wherein the sequence c(n) satisfies: {c(6),c(5),c(4),c(3),c(2),c(1),c(0)}={1,1,1,0,1,1,0}.
3. The apparatus according to claim 1 , wherein the sequence c(n) is:
{1 0 0 0 0 1 0 1 0 1 0 1 1 1 1 1 0 1 0 0 1 0 1 0 0 0 1 1 0 1 1 1 0 0 0 1 1 1 1 1 1 1 0 0 0 0 1 1 1 0 1 1 1 1 0 0 1 0 1 1 0 0 1 0 0 1 0 0 0 0 0 0 1 0 0 0 1 0 0 1 1 0 0 0 1 0 1 1 1 0 1 0 1 1 0 1 1 0 0 0 0 0 1 1 0 0 1 1 0 1 0 1 0 0 1 1 1 0 0 1 1 1 1 0 1 1 0}.
4. The apparatus according to claim 1 , wherein a generator polynomial of the sequence f 1 (n) is g(x)=x 7 +x 4 +1, and a generator polynomial of the sequence f 2 (n) is g(x)=x 7 +x+1.
5. The apparatus according to claim 1 , wherein the secondary synchronization signal sequence y(n) satisfies:
y
(
n
)
=
x
1
(
(
n
+
m
+
k
)
mod
N
)
·
x
2
(
(
n
+
k
)
mod
N
)
;
wherein x 1 (n)=1−2·f 1 (n), x 2 (n)=1−2·f 2 (n), and N=127, n=0, 1, 2, . . . , N−1, k=0, 1, 2, . . . , N−1, m=0, 1, 2, . . . , N−1.
6. The apparatus according to claim 1 , wherein the secondary synchronization signal sequence is based on a gold sequence, and the gold sequence is based on the sequence f 1 (n) and the sequence f 2 (n).
7. The apparatus according to claim 1 , wherein one or more of the following sequences are m sequences:
the sequence c(n);
the sequence f 1 (n); or
the sequence f 2 (n).
8. The apparatus according to claim 1 , wherein the secondary synchronization signal sequence y(n) satisfies:
y
m
,
k
(
n
)
=
1
-
2
·
g
m
,
k
(
n
)
;
and
wherein g m,k (n)=(f 1 ((n+m+k)mod N)+f 2 (n+k)mod N))mod 2, N=127, n=0, 1, 2, . . . , N−1, k=0, 1, 2, . . . , N−1, m=0, 1, 2, . . . , N−1.
9. The apparatus according to claim 1 , wherein the primary synchronization signal and the secondary synchronization signal have a same central frequency.
10. A method, comprising:
generating a primary synchronization signal and a secondary synchronization signal; and
transmitting the primary synchronization signal and the secondary synchronization signal;
wherein the primary synchronization signal is based on a primary synchronization signal sequence s(n), the primary synchronization signal sequence s(n) is based on a sequence c(n), 0≤n≤126, a recursion formula of the sequence c(n) satisfies: c(n+7)=(c(n+4)+c(n))mod 2, and the primary synchronization signal sequence s(n) satisfies one of:
s
(
n
)
=
1
-
2
·
c
(
(
n
)
mod
127
)
;
s
(
n
)
=
1
-
2
·
c
(
(
n
+
43
)
mod
127
)
;
or
s
(
n
)
=
1
-
2
·
c
(
(
n
+
86
)
mod
127
)
;
and
wherein the secondary synchronization signal is based on a secondary synchronization signal sequence, and the secondary synchronization signal sequence is based on a sequence f 1 (n) and a sequence f 2 (n), wherein the sequence f 1 (n) has a same recursion formula as the sequence c(n) and a recursion formula of the sequence f 2 (n) satisfies: c(n+7)=(c(n+1)+c(n))mod 2, 127 subcarriers in a first orthogonal frequency division multiplexing (OFDM) symbol are for the primary synchronization signal sequence s(n), and 127 subcarriers in a second OFDM symbol are for the secondary synchronization signal sequence.
11. The method according to claim 10 , wherein the sequence c(n) satisfies: {c(6),c(5),c(4),c(3),c(2),c(1),c(0)}={1,1,1,0,1,1,0}.
12. The method according to claim 10 , wherein the secondary synchronization signal sequence y(n) satisfies:
y
(
n
)
=
x
1
(
(
n
+
m
+
k
)
mod
N
)
·
x
2
(
(
n
+
k
)
mod
N
)
;
and
wherein x 1 (n)=1−2·f 1 (n), x 2 (n)=1−2·f 2 (n), and N=127, n=0, 1, 2, . . . , N−1, k=0, 1, 2, . . . , N−1, m=0, 1, 2, . . . , N−1.
13. The method according to claim 10 , wherein the secondary synchronization signal sequence is based on a gold sequence, and the gold sequence is based on the sequence f 1 (n) and the sequence f 2 (n).
14. The method according to claim 10 , wherein one or more of the following sequences are m sequences:
the sequence c(n);
the sequence f 1 (n); or
the sequence f 2 (n).
15. The method according to claim 10 , wherein the secondary synchronization signal sequence y(n) satisfies:
y
m
,
k
(
n
)
=
1
-
2
·
g
m
,
k
(
n
)
;
and
wherein g m,k (n)=(f 1 ((n+m+k)mod N)+f 2 ((n+k)mod N))mod 2, N=127, n=0, 1, 2, . . . , N−1, k=0, 1, 2, . . . , N−1, m=0, 1, 2, . . . , N−1.
16. The method according to claim 10 , wherein the primary synchronization signal and the secondary synchronization signal have same central frequency.
17. A non-transitory computer-readable medium, comprising instructions that, when executed by one or more processors, cause an apparatus to:
generate a primary synchronization signal and a secondary synchronization signal; and
transmit the primary synchronization signal and the secondary synchronization signal;
wherein the primary synchronization signal is based on a primary synchronization signal sequence s(n), and the primary synchronization signal sequence s(n) is based on a sequence c(n), 0≤n≤126, a recursion formula of the sequence c(n) satisfies: c(n+7)=(c(n+4)+c(n))mod 2, and the primary synchronization signal sequence s(n) satisfies one of:
s
(
n
)
=
1
-
2
·
c
(
(
n
)
mod
127
)
;
s
(
n
)
=
1
-
2
·
c
(
(
n
+
43
)
mod
127
)
;
or
s
(
n
)
=
1
-
2
·
c
(
(
n
+
86
)
mod
127
)
;
and
wherein the secondary synchronization signal is based on a secondary synchronization signal sequence, and the secondary synchronization signal sequence is based on a sequence f 1 (n) and a sequence f 2 (n), wherein the sequence f 1 (n) has a same recursion formula as the sequence c(n) and a recursion formula of the sequence f 2 (n) satisfies: c(n+7)=(c(n+1)+c(n))mod 2, 127 subcarriers in a first orthogonal frequency division multiplexing (OFDM) symbol are for the primary synchronization signal sequence s(n), and 127 subcarriers in a second OFDM symbol are for the secondary synchronization signal sequence.
18. The non-transitory computer-readable medium according to claim 17 , wherein the sequence c(n) satisfies: {c(6),c(5),c(4),c(3),c(2),c(1),c(0)}={1,1,1,0,1,1,0}.
19. The non-transitory computer-readable medium according to claim 17 , wherein the sequence c(n) is:
{1 0 0 0 0 1 0 1 0 1 0 1 1 1 1 1 0 1 0 0 1 0 1 0 0 0 1 1 0 1 1 1 0 0 0 1 1 1 1 1 1 1 0 0 0 0 1 1 1 0 1 1 1 1 0 0 1 0 1 1 0 0 1 0 0 1 0 0 0 0 0 0 1 0 0 0 1 0 0 1 1 0 0 0 1 0 1 1 1 0 1 0 1 1 0 1 1 0 0 0 0 0 1 1 0 0 1 1 0 1 0 1 0 0 1 1 1 0 0 1 1 1 1 0 1 1 0}.
20. The non-transitory computer-readable medium according to claim 17 , wherein a generator polynomial of the sequence f 1 (n) is g(x)=x 7 +x 4 +1, and a generator polynomial of the sequence f 2 (n) is g(x)=x 7 +x+1.
21. The non-transitory computer-readable medium according to claim 17 , wherein the secondary synchronization signal sequence y(n) satisfies:
y
(
n
)
=
x
1
(
(
n
+
m
+
k
)
mod
N
)
·
x
2
(
(
n
+
k
)
mod
N
)
;
wherein x 1 (n)=1−2·f 1 (n), x 2 (n)=1−2·f 2 (n), and N=127, n=0, 1, 2, . . . , N−1, k=0, 1, 2, . . . , N−1, m=0, 1, 2, . . . , N−1.
22. The non-transitory computer-readable medium according to claim 17 , wherein the secondary synchronization signal sequence is based on a gold sequence, and the gold sequence is based on the sequence f 1 (n) and the sequence f 2 (n).
23. The non-transitory computer-readable medium according to claim 17 , wherein one or more of the following sequences are m sequences:
the sequence c(n);
the sequence f 1 (n); or
the sequence f 2 (n).
24. The non-transitory computer-readable medium according to claim 17 , wherein the secondary synchronization signal sequence y(n) satisfies:
y
m
,
k
(
n
)
=
1
-
2
·
g
m
,
k
(
n
)
;
and
wherein g m,k (n)=(f 1 ((n+m+k)mod N)+f 2 ((n+k)mod N))mod 2, N=127, n=0, 1, 2, . . . , N−1, k=0, 1, 2, . . . , N−1, m=0, 1, 2, . . . , N−1.
25. The non-transitory computer-readable medium according to claim 18 , wherein the primary synchronization signal and the secondary synchronization signal have a same central frequency.
26. A communication device, comprising:
a processor of a network device, configured to generate a primary synchronization signal and a secondary synchronization signal, the primary synchronization signal being based on a first synchronization sequence s(n), and the secondary synchronization signal being based on a second synchronization sequence y(n) that satisfies:
y(n)=[1−2·f 1 ((n+k 1 )mod 127)]·[1−2·f 2 ((n+k)mod 127)], wherein n is an integer, n=0, 1, . . . 126, k is an integer and k<127, and k, is an integer and k 1 <253, and f 1 (n) and f 2 (n) are sequences; and
a transceiver, configured to transmit the primary synchronization signal and the secondary synchronization signal.
27. The device according to claim 26 , wherein the first synchronization sequence s(n) is based on a first sequence c(n), and a recursion formula of the sequence c(n) satisfies: c(n+7)=(c(n+4)+c(n))mod 2.
28. The device according to claim 26 , wherein one of sequences f 1 (n) or f 2 (n) has a same recursion formula as the sequence c(n).
29. The apparatus according to claim 1 , wherein the secondary synchronization signal sequence is a binary phase shift keying (BPSK) modulated Gold sequence.
30. The method according to claim 10 , wherein the secondary synchronization signal sequence is a binary phase shift keying (BPSK) modulated Gold sequence.
31. The non-transitory computer-readable medium according to claim 17 , wherein the secondary synchronization signal sequence is a binary phase shift keying (BPSK) modulated Gold sequence.