Method and device for searching cell

1. A method for searching a cell, which is applied to User Equipment (UE), comprising:

performing time slot synchronization;

identifying a primary scrambling code group and performing frame synchronization according to hashed values of code numbers of Secondary Synchronization Codes (SSCs) in any several consecutive timeslots; and

obtaining a primary scrambling code in the primary scrambling code group according to the primary scrambling code group to complete cell searching.

2. The method for searching the cell according to claim 1 , wherein a Primary Synchronization Code (P-SCH) is used for capturing the primary synchronisation code by matching a peak value of a filtered output signal to determine a timeslot boundary, so as to complete timeslot synchronization.

3. The method for searching the cell according to claim 2 , wherein identifying the primary scrambling code group and performing frame synchronization according to the hashed values of code numbers of SSCs in any several consecutive timeslots comprises:

obtaining code numbers of the SSCs in any five consecutive timeslots, which are marked as C P , P=0, 1, 2, 3, 4;

recording the C P , P=0, 1, 2, 3, 4 as F k =(C k , C k+1 , C k+2 ) k=0, 1, 2, wherein when k=0, a hashed value F 0 is calculated according to a hash formula;

judging whether or not there is a value D i,j which is equal to F 0 in a lookup table D obtained in advance by calculating according to the hash formula; if yes, determining that the primary scrambling code group number is i and C k actually represents the (j×3) th timeslot of one frame, so as to complete the scrambling code group identification and frame synchronization process; if no, calculating a hashed value F 1 when k=1 by the hash formula and further judging whether or not there is a value D i,j which is equal to F 1 in the lookup table D; if yes, determining that the primary scrambling code group number is i and C k actually represents the (j×3+1) th timeslot of one frame, so as to complete the scrambling code group identification and frame synchronization process; if no, calculating a hashed value F 2 when k=2 by the hash formula and finally judging whether or not there is a value D i,j which is equal to F 2 in the lookup table D; if yes, determining that the primary scrambling code group number is i and C k actually represents the (j×3+2) th timeslot of one frame, so as to complete the scrambling code group identification and frame synchronization process; and if no, ending a flow.

4. The method for searching the cell according to claim 1 , wherein identifying the primary scrambling code group and performing frame synchronization according to the hashed values of code numbers of SSCs in any several consecutive timeslots comprises:

obtaining code numbers of the SSCs in any five consecutive timeslots, which are marked as C P , P=0, 1, 2, 3, 4;

recording the C P , P=0, 1, 2, 3, 4 as F k =(C k , C k+1 , C k+2 ) k=0, 1, 2, wherein when k=0, a hashed value F 0 is calculated according to a hash formula;

judging whether or not there is a value D i,j which is equal to F 0 in a lookup table D obtained in advance by calculating according to the hash formula; if yes, determining that the primary scrambling code group number is i and C k actually represents the (j×3) th timeslot of one frame, so as to complete the scrambling code group identification and frame synchronization process; if no, calculating a hashed value F 1 when k=1 by the hash formula and further judging whether or not there is a value D i,j which is equal to F 1 in the lookup table D; if yes, determining that the primary scrambling code group number is i and C k actually represents the (j×3+1) th timeslot of one frame, so as to complete the scrambling code group identification and frame synchronization process; if no, calculating a hashed value F 2 when k=2 by the hash formula and finally judging whether or not there is a value D i,j which is equal to F 2 in the lookup table D; if yes, determining that the primary scrambling code group number is i and C k actually represents the (j×3+2) th timeslot of one frame, so as to complete the scrambling code group identification and frame synchronization process; and if no, ending a flow.

5. The method for searching the cell according to claim 4 , wherein obtaining the lookup table D in advance by calculating according to the hash formula comprises:

dividing the SSCs in 64 rows and 15 columns into 64×5 groups in a manner of dividing the columns into 5 groups by forming every three columns into one group, obtaining a numerical value D i,j by calculating the code numbers of SSCs in each group according to the hash formula, and accordingly obtaining a lookup table D with 64×5.

6. The method for searching the cell according to claim 4 , wherein the hash formula is:

D i,j =α·g i,j·3+0 +β·g i,j·3+1 +δ·g i,j·3+2 ,i= 0, . . . ,63, j= 0, . . . ,4;

where i represents the primary scrambling code group number in the table, j represents the j th hash in each primary scrambling code group, g i,j·3+0 represents the code number of the SSC corresponding to the j·3+0 th timeslot in the i th scrambling code group in the table, and α, β, and δ are coefficients.

7. A device for searching a cell, which is located in User Equipment (UE), comprising:

a timeslot synchronization component, which is coupled to a primary scrambling code group identification and frame synchronization component, configured to perform timeslot synchronization;

the primary scrambling code group identification and frame synchronization component, which is coupled to a cell searching component, configured to identify a primary scrambling code group and perform frame synchronization according to hashed values of code numbers of secondary synchronization codes (SSCs) in any several consecutive timeslots; and

the cell searching component, which is coupled to the primary scrambling code group identification and frame synchronization component, configured to obtain a primary scrambling code in the primary scrambling code group according to the primary scrambling code group to complete cell searching.

8. The device for searching the cell according to claim 7 , wherein the timeslot synchronization component uses a Primary Synchronization Code (P-SCH) to capture a primary synchronisation code by matching a peak value of a filtered output signal to determine a timeslot boundary, so as to complete timeslot synchronization.

9. The device for searching the cell according to claim 8 , wherein the primary scrambling code group identification and frame synchronization component is configured to

obtain code numbers of the SSCs in any five consecutive timeslots, which are marked as C P , P=0, 1, 2, 3, 4;

record the C P , P=0, 1, 2, 3, 4 as F k =(C k , C k+1 , C k+2 ) k=0, 1, 2, wherein when k=0, a hashed value F 0 is calculated according to a hash formula; and

judge whether or not there is a value D i,j which is equal to F 0 in a lookup table D obtained in advance by calculating according to the hash formula; if yes, determine that the primary scrambling code group number is i, wherein C k actually represents the (j×3) th timeslot of one frame, so as to complete the scrambling code group identification and frame synchronization process; if no, calculate a hashed value F 1 when k=1 by the hash formula and further judge whether or not there is a value D i,j which is equal to F 1 in the lookup table D; if yes, determine that the primary scrambling code group number is i, wherein C k actually represents the (j×3+1) th timeslot of one frame, so as to complete the scrambling code group identification and frame synchronization process; if no, calculate a hashed value F 2 when k=2 by the hash formula and finally judging whether or not there is a value D i,j which is equal to F 2 in the lookup table D; if yes, determine that the primary scrambling code group number is i, wherein C k actually represents the (j×3+2) th timeslot of one frame, so as to complete the scrambling code group identification and frame synchronization process; if no, end the flow.

10. The device for searching the cell according to claim 7 , wherein the primary scrambling code group identification and frame synchronization component is configured to

obtain code numbers of the SSCs in any five consecutive timeslots, which are marked as C P , P=0, 1, 2, 3, 4;

record the C P , P=0, 1, 2, 3, 4 as F k =(C k , C k+1 , C k+2 ) k=0, 1, 2, wherein when k=0, a hashed value F 0 is calculated according to a hash formula; and

judge whether or not there is a value D i,j which is equal to F 0 in a lookup table D obtained in advance by calculating according to the hash formula; if yes, determine that the primary scrambling code group number is i, wherein C k actually represents the (j×3) th timeslot of one frame, so as to complete the scrambling code group identification and frame synchronization process; if no, calculate a hashed value F 1 when k=1 by the hash formula and further judge whether or not there is a value D i,j which is equal to F 1 in the lookup table D; if yes, determine that the primary scrambling code group number is i, wherein C k actually represents the (j×3+1) th timeslot of one frame, so as to complete the scrambling code group identification and frame synchronization process; if no, calculate a hashed value F 2 when k=2 by the hash formula and finally judging whether or not there is a value D i,j which is equal to F 2 in the lookup table D; if yes, determine that the primary scrambling code group number is i, wherein C k actually represents the (j×3+2) th timeslot of one frame, so as to complete the scrambling code group identification and frame synchronization process; if no, end the flow.

11. The device for searching the cell according to claim 10 , wherein the primary scrambling code group identification and frame synchronization component is configured to

divide the SSCs in 64 rows and 15 columns into 64×5 groups in a manner of dividing the columns into 5 groups by forming every three columns into one group, obtain a numerical value D i,j by calculating the SSC code numbers in each group according to the hash formula, and accordingly obtain the lookup table D with 64×5.

12. The device for searching the cell according to claim 10 , wherein the hash formula is

D i,j =α·g i,j·3+ +β·g i,j·3+1 +δ·g i,j·3+2 ,i= 0, . . . ,63, j= 0, . . . ,4;

where i represents the primary scrambling code group number in the table, j represents the j th hash in each primary scrambling code group, g i,j·3+0 represents the code number of the SSC corresponding to the j·3+0 th timeslot in the i th scrambling code group in the table, and α, β, and δ are coefficients.