Random access preamble sequence generation method and user equipment
A random access preamble sequence generation method and user equipment are provided. The method includes the following: when receiving first notification signaling sent by a base station, determining, by UE, to calculate a cyclic shift value by using a first solution; obtaining a first logical root sequence number, and determining a root sequence based on the first logical root sequence number; and generating a random access preamble sequence based on the root sequence and the cyclic shift value, where the first solution is a solution of calculating the cyclic shift value when a Doppler shift of the UE is less than a first preset value and greater than a second preset value, the first preset value is less than twice of a physical random access channel (PRACH) subcarrier spacing, the second preset value is greater than the PRACH subcarrier spacing.
1. A communications apparatus comprising:
a receiver, configured to cooperate with a processor to receive signaling from a base station, wherein the signaling carries a target Ncs index for determining a Ncs value, wherein the Ncs value is for calculating a cyclic shift value; and
the processor, configured to:
obtain the Ncs value indicated by the target Ncs index, according to the target Ncs index and a preset correspondence between a set of Ncs indexes and a set of Ncs values, wherein the set of Ncs values comprises {15, 18, 22, 26, 32, 38, 46, 55, 68, 82, 100, 118, 137};
calculate the cyclic shift value based on the Ncs value indicated by the target Ncs index;
obtain a first logic root sequence number;
obtain a root sequence based on the first logic root sequence number;
generate a random access preamble sequence based on the root sequence and the cyclic shift value; and
perform random access with the base station using the generated random access preamble sequence.
2. The communications apparatus according to claim 1 , wherein the preset correspondence between the set of Ncs indexes and the set of Ncs values, comprising:
Ncs Index
Ncs
0
15
1
18
2
22
3
26
4
32
5
38
6
46
7
55
8
68
9
82
10
100
11
118
12
137.
3. The communications apparatus according to claim 1 , further comprising:
a memory, configured to store the preset correspondence between the set of Ncs indexes and the set of Ncs values.
4. The communications apparatus according to claim 1 , wherein the receiver is further configured to cooperate with the processor to receive at least one of system information or mobile control information, wherein the at least one of the system information or the mobile control information comprises the signaling.
5. The communications apparatus according to claim 1 , wherein the random access preamble sequence is defined as X u,v (n), wherein X u,v (n)=X u ((n+C v ) mod N zc ), wherein X u (n)=e ∧ ((−j*π*n*(n+1))/N zc ), 0<n<N zc −1, wherein C v is the cyclic shift value, wherein u is a physical root sequence number, wherein X u (n) is a Zadoff-Chu (ZC) sequence, and wherein N zc is a length of the ZC sequence.
6. The communications apparatus according to claim 1 , wherein the signaling carries the first logic root sequence number.
7. The communications apparatus according to claim 1 , wherein the processor is further configured to determine a solution for calculating the cyclic shift value according to the signaling received by the receiver.
8. The communications apparatus according to claim 1 , wherein the communications apparatus is user equipment.
9. A random access method comprising:
receiving signaling from a base station, wherein the signaling carries a target Ncs index for determining a Ncs value, wherein the Ncs value is for calculating a cyclic shift value;
obtaining the Ncs value indicated by the target Ncs index, according to the target Ncs index and a preset correspondence between a set of Ncs indexes and a set of Ncs values, wherein the set of Ncs values comprises {15, 18, 22, 26, 32, 38, 46, 55, 68, 82, 100, 118, 137};
calculating the cyclic shift value based on the Ncs value indicated by the target Ncs index:
obtaining a first logic root sequence number;
determining a root sequence based on the first logic root sequence number;
generating a random access preamble sequence based on the root sequence and the cyclic shift value; and
performing random access with the base station using the generated random access preamble sequence.
10. The method according to claim 9 , wherein the preset correspondence between the set of Ncs indexes and the set of Ncs values, comprising:
Ncs Index
Ncs
0
15
1
18
2
22
3
26
4
32
5
38
6
46
7
55
8
68
9
82
10
100
11
118
12
137.
11. The method according to claim 9 , further comprising:
storing the preset correspondence between the set of Ncs indexes and the set of Ncs values.
12. The method according to claim 9 , further comprising:
receiving at least one of system information or mobile control information, wherein the at least one of the system information or the mobile control information comprises the signaling.
13. The method according to claim 9 , wherein the random access preamble sequence is defined as X u,v (n), wherein X u,v (n)=X u ((n+C v ) mod N zc ), wherein X u (n)=e ∧ ((−j*π*n*(n+1))/N zc ), 0<n<N zc −1, wherein C v is the cyclic shift value, wherein u is a physical root sequence number, wherein X u (n) is a Zadoff-Chu (ZC) sequence, and wherein N zc is a length of the ZC sequence.
14. The method according to claim 9 , wherein the signaling carries the first logic root sequence number.
15. The method according to claim 9 , further comprising: determining a solution for calculating the cyclic shift value according to the signaling received by the receiver.
16. A non-transitory computer readable medium, comprising computer program instruction which when executed by one or more processors cause the one or more processors to execute operations including:
receiving signaling from a base station, wherein the signaling carries a target Ncs index for determining a Ncs value, wherein the Ncs value is for calculating a cyclic shift value;
obtaining the Ncs value indicated by the target Ncs index, according to the target Ncs index and a preset correspondence between a set of Ncs indexes and a set of Ncs values, wherein the set of Ncs values comprises 15, 18, 22, 26, 32, 38, 46, 55, 68, 82, 100, 118, 137};
calculating the cyclic shift value based on the Ncs value indicated by the target Ncs index:
obtaining a first logic root sequence number;
determining a root sequence based on the first logic root sequence number;
generating a random access preamble sequence based on the root sequence and the cyclic shift value; and
performing random access with the base station using the generated random access preamble sequence.
17. The non-transitory computer readable medium according to claim 16 , wherein the preset correspondence between the set of Ncs indexes and the set of Ncs values, comprising:
Ncs Index
Ncs
0
15
1
18
2
22
3
26
4
32
5
38
6
46
7
55
8
68
9
82
10
100
11
118
12
137.
18. The communications apparatus according to claim 5 , wherein N zc =839 or N zc =139.
19. The method according to claim 13 , wherein N zc =839 or N zc =139.