Method and apparatus for generating secondary synchronization signals

1. A method for generating secondary synchronization signals, executed by a base station, comprising:

determining a value of iteration times M according to a total number N of cell ID groups or a cell ID group index N ID (1) , wherein M is a natural number;

calculating to obtain M cyclic shift accumulation parameters q k (k=0, 1 . . . M−1) through M times of iterations;

calculating a common cyclic shift factor m′ through q 0 ;

calculating a first cyclic shift value m 0 and a second cyclic shift value m 1 according to m′; and

generating the secondary synchronization signals according to m 0 and m 1 .

2. The method according to claim 1 , wherein the step of calculating to obtain the M cyclic shift accumulation parameters q k (k=0, 1 . . . M−1) through M times of iterations comprises:

q

M

=

⌊

N

ID

(

1

)

/

30

⌋

;

q

k

-

1

=

⌊

N

ID

(

1

)

+

q

k

⁡

(

q

k

+

1

)

/

2

30

⌋

⁢

(

1

≤

k

≤

M

)

.

3. The method according to claim 1 , wherein the step of calculating the common cyclic shift factor m′ through q 0 comprises:

m′=N ID (1) +q 0 ( q 0 +1)/2.

4. The method according to claim 1 , wherein the step of calculating the first cyclic shift value m 0 and the second cyclic shift value m 1 according to m′ comprises:

m 0 =m ′ mod 31 ,m 1 =( m 0 +└m′/ 31┘+1)mod 31.

5. The method according to claim 1 , wherein the step of determining the value of M according to the total number N of the cell ID groups comprises:

when N<234, M=1;

when 234=<N<329, M=2;

when 329=<N<387, M=3;

when 387=<N<465, M=9.

6. The method according to claim 1 , wherein the step of determining the value of M according to the cell ID group index Ng comprises:

when N ID (1) <234, M=1;

when 234=<N ID (1) <329, M=2;

when 329=<N ID (1) <387, M=3;

when 387=<N ID (1) <465, M=9.

7. The method according to claim 1 , wherein the step of generating the secondary synchronization signals according to m 0 and m 1 comprises:

obtaining a first shift sequence by shifting a Golden sequence according to m 0 ; and

obtaining a second shift sequence by shifting the Golden sequence according to m 1 .

8. The method according to claim 7 , wherein after the step of generating the secondary synchronization signals according to m 0 and m 1 , the method further comprises:

on time slot 0 , transmitting the first shift sequence on a carrier with an even index, and transmitting the second shift sequence on a carrier with an odd index;

on time slot 10 , transmitting the second shift sequence on a carrier with an even index, and transmitting the first shift sequence on a carrier with an odd index.

9. The method according to claim 8 , wherein after the step of transmitting the first shift sequence and the second shift sequence, the method further comprises:

receiving a third shift sequence on a carrier with an even index on a current time slot, and receiving a fourth shift sequence on a carrier with an odd index on the current time slot;

determining a third cyclic shift value m 2 corresponding to the third shift sequence and a fourth cyclic shift value m 3 corresponding to the fourth shift sequence;

comparing m 2 and m 3 ;

if m 2 is less than m 3 , representing that the current time slot is time slot 0 ;

if m 2 is greater than m 3 , representing that the current time slot is time slot 10 .

10. The method according to claim 9 , wherein after the step of determining m 2 and m 3 , the method further comprises:

obtaining the cell ID group index N ID (1) according to m 2 and m 3 , wherein

N

ID

(

1

)

=

∑

i

=

0



m

2

-

m

3



-

1

⁢

W

i

+

m

2

W

i

=

Mod

⁡

(

31

-

i

,

31

)

.

11. An apparatus for generating secondary synchronization signals, comprising:

a first processing module, configured to determine a value of iteration times M according to a total number N of cell ID groups or a cell ID group index N ID (1) , wherein M is a natural number;

a second processing module, configured to calculate to obtain M cyclic shift accumulation parameters q k (k=0, 1 . . . M−1) through M times of iterations;

a third processing module, configured to calculate a common cyclic shift factor m′ through q 0 ;

a fourth processing module, configured to calculate a first cyclic shift value m 0 and a second cyclic shift value m 1 according to m′; and

a generation module, configured to generate the secondary synchronization signals according to m 0 and m 1 .

12. The apparatus according to claim 11 , wherein the second processing module is configured to calculate to obtain the M cyclic shift accumulation parameters q k (k=0, 1 . . . M−1) through the following formula:

q

M

=

⌊

N

ID

(

1

)

/

30

⌋

;

q

k

-

1

=

⌊

N

ID

(

1

)

+

q

k

⁡

(

q

k

+

1

)

/

2

30

⌋

⁢

(

1

≤

k

≤

M

)

.

13. The apparatus according to claim 11 , wherein the third processing module is configured to calculate the common cyclic shift factor m′ through the following formula:

m′=N ID (1) +q 0 ( q 0 +1)/2.

14. The apparatus according to claim 11 , wherein the fourth processing module is configured to calculate the first cyclic shift value m 0 and the second cyclic shift value m 1 through the following formula:

m 0 =m ′ mod 31 ,m 1 =( m 0 +└m′/ 31┘+1)mod 31.

15. The apparatus according to claim 11 , wherein the generation module comprises:

a first generation sub-module, configured to obtain a first shift sequence by shifting a Golden sequence according to m 0 ; and

a second generation sub-module, configured to obtain a second shift sequence by shifting the Golden sequence according to m 1 .