Method, base station, and user equipment for accessing physical random access channel

• US 9,439,222 B2
• Filed: 03/11/2013
• Issued: 09/06/2016
• Est. Priority Date: 02/01/2012
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Liang, Yongming, Zhang, Jiayin, Liu, Kunpeng
• Primary Examiner(s): Vu, Huy D
• Assistant Examiner(s): Ahmed, Nizam
• Application Number:
  US13/793,849
• Publication Number:
  US 20130286958A1
• Time in Patent Office: 1,275 Days
• Field of Search: 370/329
• US Class Current: 1/1
• CPC Class Codes: H04J 11/0069 Cell search, i.e. determining cell identity [cell-ID] design of multiplexing codes H04J13/00; processing access restriction or access information H04W48/16; discovery of network devices for network data management H04W8/005; sounding signals for channel estimation H04L25/0226; structure of reference signals in multicarrier modulation systems H04L27/2613; frame, time or carrier synchronisation in multicarrier modulation systems H04L27/2655
• CPC Class Codes: H04J 2211/001 using small cells within macro cells, e.g. femto, pico or microcells
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access
• CPC Class Codes: H04W 74/0866 using a dedicated channel for access

Abstract

A method, a base station, and a user equipment for PRACH access are provided. The method includes: determining a PRACH sequence group used by multiple base stations, where the multiple base stations use a same cell identity and include a macro base station and at least one pico base station, the PRACH sequence group includes k1 first PRACH sequences, k2second PRACH sequences, k3 third PRACH sequences, k4 fourth PRACH sequences, k5 fifth PRACH sequences, and k6 sixth PRACH sequences, k1 and k4 are positive integers, and k2, k3, k5, and k6 are nonnegative integers; and sending an indication parameter of the PRACH sequence group to the UE for the UE to randomly access a network, where the indication parameter is used for indicating the first PRACH sequences to the sixth PRACH sequences. thereby the fierceness of contention access to a PRACH can be reduced.

Claims

1. A method for accessing a physical random access channel (PRACH), the method comprising:

determining a PRACH sequence group used by multiple base stations, wherein the multiple base stations use a same cell identity and comprise a macro base station and at least one pico base station, the PRACH sequence group based on two root sequences, a first root sequence associated with the macro base station and a second root sequence associated with the pico base station, the PRACH sequence group comprises k1 first PRACH sequences, k2 second PRACH sequences, k3 third PRACH sequences, k4 fourth PRACH sequences, k5 fifth PRACH sequences, and K6 sixth PRACH sequences, k1 and K4 are positive integers, and k2, k3 , k5, and k6 are nonnegative integers, wherein the first PRACH sequences to the third PRACH sequences are based on the first root sequence and the fourth PRACH sequences to the sixth PRACH sequences are based on the second root sequence; and

sending an indication parameter of the PRACH sequence group to a user equipment UE for the UE to randomly access a network, wherein the indication parameter is used for indicating the first PRACH sequences to the sixth PRACH sequences.

2. The access method according to claim 1, wherein the first PRACH sequences and the fourth PRACH sequences are PRACH sequences of contention-based Group A, the second PRACH sequences and the fifth PRACH sequences are PRACH sequences of contention-based Group B, and the third PRACH sequences and the sixth PRACH sequences are non-contention based PRACH sequences.

3. The access method according to claim 1, wherein the indication parameter comprises a starting point identity of the first root sequence, length information of the first root sequence, a starting point identity of the second root sequence, and length information of the second root sequence, wherein the access method further comprises any of:

the length information of the first root sequence is an ending point identity of the first root sequence or the number of sequences comprised in the first root sequence; and

the length information of the second root sequence is an ending point identity of the second root sequence or the number of sequences comprised in the second root sequence; and

,

the first and second root sequences are combined such that the first PRACH sequences to the sixth PRACH sequences are based on one root sequence, the one root sequence divided into macro and pico sequences, and the indication parameter comprises a starting point identity of the one root sequence and length information of the one root sequence, wherein the length information of the one root sequence is an ending point identity of the one root sequence or the number of sequences comprised in the one root sequence.

4. The access method according to claim 3, wherein K is a total number of PRACH sequences included in the PRACH sequence group such that k1+k2+k3=N, k4+k5+k6=K−

N, K and N are positive integers, and K>

N; and

the indication parameter further comprises k1, kx,k4, and ky, wherein kx=k1+k2, ky=k4+k5, wherein k1 is the number of sequences of Group A, defined in system information (SIB2) of the macro base station;

kx is the number of contention-based sequences of the macro base station, k4 is the number of sequences of Group A, defined in SIB2 of the pico base station; and

ky is the number of contention-based sequences of the pico base station.

5. The access method according to claim 1, wherein,

the first PRACH sequences to the third PRACH sequences are used for random access to the macro base station or the pico base station, and the fourth PRACH sequences to the sixth PRACH sequences are used for random access to the pico base station.

6. A method for accessing a physical random access channel (PRACH), the method comprising:

receiving an indication parameter of a PRACH sequence group used by multiple base stations, wherein the multiple base stations use a same cell identity and comprise a macro base station and at least one pico base station, the PRACH sequence group based on two root sequences, a first root sequence associated with the macro base station and a second root sequence associated with the pico base station, and the indication parameter is used for indicating first PRACH sequences to sixth PRACH sequences, wherein the first PRACH sequences to the sixth PRACH sequences are comprised in the PRACH sequence group;

determining, according to the indication parameter, that the PRACH sequence group comprises k1 first PRACH sequences, k2 second PRACH sequences, k3 third PRACH sequences, k4 fourth PRACH sequences, k5 fifth PRACH sequences, and k6 sixth PRACH sequences, wherein k1 and k4 are positive integers, and k2, k3 , k5, and k6 are nonnegative integers, wherein the first PRACH sequences to the third PRACH sequences are based on the first root sequence and the fourth PRACH sequences to the sixth PRACH sequences are based on the second root sequence; and

selecting a PRACH sequence from the PRACH sequence group to randomly access a network.

7. The access method according to claim 6, wherein the selecting the PRACH sequence from the PRACH sequence group to randomly access the network comprises any of:

selecting the PRACH sequence from the first PRACH sequences or the fourth PRACH sequences to randomly access the network, wherein the selected PRACH sequence is a sequence of contention-based Group A;

selecting the PRACH sequence from the second PRACH sequences or the fifth PRACH sequences to randomly access the network, wherein the selected PRACH sequence is a sequence of contention-based Group B; and

selecting the PRACH sequence from the third PRACH sequences or the sixth PRACH sequences to randomly access the network, wherein the selected PRACH sequence is a non-contention based PRACH sequence.

8. The access method according to claim 6, wherein the indication parameter comprises a starting point identity of a first root sequence, length information of the first root sequence, a starting point identity of a second root sequence, and length information of the second root sequence;

the determining, according to the indication parameter, that the PRACH sequence group comprises k1 first PRACH sequences, k2 second PRACH sequences, k3 third PRACH sequences, k4 fourth PRACH sequences, k5 fifth PRACH sequences, and k6 sixth PRACH sequences comprises any of;

determining, according to a starting point identity of a first root sequence, length information of the first root sequence, a starting point identity of a second root sequence, and length information of the second root sequence which are comprised in the indication parameter, that the first PRACH sequences to the third PRACH sequences are based on the first root sequence, and the fourth PRACH sequences to the sixth PRACH sequences are based on the second root sequence,

wherein the length information of the first root sequence is an ending point identity of the first root sequence or the number of sequences comprised in the first root sequence; and

the length information of the second root sequence is an ending point identity of the second root sequence or the number of sequences comprised in the second root sequence; and

,

wherein the first and second root sequences are combined such that the first PRACH sequences to the sixth PRACH sequences are based on one root sequence, the one root sequence divided into macro and pico sequences, the indication parameter comprises a starting point identity of the one root sequence and length information of the one root sequence;

the determining, according to the indication parameter, that the PRACH sequence group comprises k1 first PRACH sequences, k2 second PRACH sequences, k3 third PRACH sequences, k4 fourth PRACH sequences, k5 fifth PRACH sequences, and k6 sixth PRACH sequences comprises;

determining, according to a starting point identity of the one root sequence and length information of the one root sequence which are comprised in the indication parameter, that the first PRACH sequences to the sixth PRACH sequences are based on the one root sequence,

wherein the length information of the root sequence is an ending point identity of the root sequence or the number of sequences comprised in the root sequence.

9. The access method according to claim 8, wherein the indication parameter further comprises k1, kx, k4 , and ky;

the determining, according to the indication parameter, that the PRACH sequence group comprises k1 first PRACH sequences, k2 second PRACH sequences, k3 third PRACH sequences, k4 fourth PRACH sequences, k5 fifth PRACH sequences, and k6 sixth PRACH sequences further comprises;

determining k1 to k6 according to k1, kx, k4 , and ky which are comprised in the indication parameter, wherein kx=k1+k2, ky=k4+k5, k1+k2+k3=N, k4+k5+k6=K-N, K and N are positive integers and K>

N with K being a total number of PRACH sequences included in the PRACH sequence group, wherein k1 is the number of sequences of Group A, defined in a system information block (SIB2) of the macro base station;

kx is the number of contention-based sequences of the macro base station, k4 is the number of sequences of Group A, defined in a system information block (SIB2) of the pico base station; and

ky is the number of contention-based sequences of the pico base station.

10. The access method according to claim 6, wherein the selecting a PRACH sequence from the PRACH sequence group to randomly access a network, comprises any of:

selecting the PRACH sequence from the first PRACH sequences to the third PRACH sequences for random access to the macro base station or the pico base station; and

,

selecting the PRACH sequence from the fourth PRACH sequences to the sixth PRACH sequences for random access to the pico base station.

11. A method for accessing a physical random access channel PRACH, the method comprising:

determining M PRACH sequence groups used by L groups of base stations, wherein the L groups of base stations use a same cell identity, each PRACH sequence group of the M PRACH sequence groups comprises m1 first PRACH sequences, m2 second PRACH sequences, and m3 third PRACH sequences, M and L are positive integers and 1<

M≦

L, m1 is a positive integer, and m2 and m3 are nonnegative integers; and

multiplexing the M PRACH sequence groups in the L groups of base stations according to geographic locations of the L groups of base stations;

sending an indication parameter of the PRACH sequence group to a user equipment UE for the UE to randomly access a network, wherein the indication parameter is used for indicating the first PRACH sequences to the third PRACH sequences, wherein the first PRACH sequences to the third PRACH sequences are comprised in each PRACH sequence group of the M PRACH sequence groups.

12. The method according to claim 11, wherein the determining the M PRACH sequence groups used by the L groups of base stations comprises any of:

determining that the M PRACH sequence groups are based on one root sequence, wherein the indication parameter comprises a starting point identity of the root sequence and length information of the root sequence; and

,

determining that the M PRACH sequence groups are based on M root sequences, wherein the indication parameter comprises starting point identities of the M root sequences and length information of the M root sequences,

wherein the length information of the root sequence is an ending point identity of the root sequence or the number of sequences comprised in the root sequence.

13. The method according to claim 12, wherein the indication parameter further comprises m1 and mx, wherein mx =m1+m2, m1 is the number of sequences of Group A, defined in a system information block (SIB2);

and mx is the number of contention-based sequences.

14. The method according to claim 11, wherein the determining the M PRACH sequence groups used by the L groups of base stations comprises any of:

allocating a PRACH sequence group that comprises more PRACH sequences to a group of base stations that belong to a high contention area and are in the L groups of base stations; and

allocating a PRACH sequence group that comprises fewer PRACH sequences to a group of base stations that belong to a low contention area and are in the L groups of base stations.

15. The method according to claim 11, wherein the indication parameter is further used for indicating identity information of a base station which corresponds to each PRACH sequence group.

16. A method for accessing a physical random access channel PRACH, the method comprising:

receiving an indication parameter of M PRACH sequence groups used by L groups of base stations, wherein the L groups of base stations use a same cell identity, and the indication parameter is used for indicating first PRACH sequences to third PRACH sequences, wherein the first PRACH sequences to the third PRACH sequences are comprised in each PRACH sequence group of the M PRACH sequence groups;

multiplexing the M PRACH sequence groups in the L groups of base stations according to geographic locations of the L groups of base stations;

determining, according to the indication parameter, that each PRACH sequence group comprises m1 first PRACH sequences, m2 second PRACH sequences, and m3 third PRACH sequences, wherein M and L are positive integers and 1 <

M<

L, m1 is a positive integer, and m2 and m3 are nonnegative integers; and

selecting a PRACH sequence from the PRACH sequence group to randomly access a network.

17. The method according to claim 16, wherein the determining, according to the indication parameter, that each PRACH sequence group comprises m1 first PRACH sequences, m2 second PRACH sequences, and m3 third PRACH sequences comprises any of:

determining, according to a starting point identity of one root sequence and length information of the root sequence which are comprised in the indication parameter, that the M PRACH sequence groups are based on the root sequence; and

,

determining, according to starting point identities of M root sequences and length information of the M root sequences, that each PRACH sequence group among the M PRACH sequence groups is based on one root sequence among the M root sequences, wherein the starting point identities of the M root sequences and the length information of the M root sequences are comprised in the indication parameter,

wherein the length information of the root sequence is an ending point identity of the root sequence or the number of sequences comprised in the root sequence.

18. The method according to claim 17, wherein the indication parameter further comprises m1 and mx, the determining, according to the indication parameter, that each PRACH sequence group comprises m1 first PRACH sequences, m2 second PRACH sequences, and m3 third PRACH sequences further comprises:

determining m1, m2, and m3 according to m1 and mx which are comprised in the indication parameter, wherein mx=m1+m2, wherein m1 is the number of sequences of Group A, defined in a system information block (SIB2); and

mx is the number of contention-based sequences.

19. A base station, comprising:

a determining unit, configured to determine a physical random access channel PRACH sequence group used by multiple base stations, wherein the multiple base stations use a same cell identity and comprise a macro base station and at least one pico base station, the PRACH sequence group based on two root sequences, a first root sequence associated with the macro base station and a second root sequence associated with the pico base station, the PRACH sequence group comprises k1 first PRACH sequences, k2 second PRACH sequences, k3 third PRACH sequences, k4 fourth PRACH sequences, k5 fifth PRACH sequences, and k6 sixth PRACH sequences, wherein k1 and k4 are positive integers, and k2, k3 , k5, and k6 are nonnegative integers, wherein the first PRACH sequences to the third PRACH sequences are based on the first root sequence and the fourth PRACH sequences to the sixth PRACH sequences are based on the second root sequence; and

a sending unit, configured to send an indication parameter of the PRACH sequence group determined by the determining unit, to a user equipment UE for the UE to randomly access a network, wherein the indication parameter is used for indicating the first PRACH sequences to the sixth PRACH sequences.

21. The base station according to claim 19, wherein the indication parameter, sent by the sending unit, comprises any of:

a starting point identity of the first root sequence, length information of the first root sequence, a starting point identity of the second root sequence, and length information of the second root sequence, wherein the length information of the first root sequence is an ending point identity of the first root sequence or the number of sequences comprised in the first root sequence; and

the length information of the second root sequence is an ending point identity of the second root sequence or the number of sequences comprised in the second root sequence; and

,

the first and second root sequences are combined such that the first PRACH sequences to the sixth PRACH sequences, determined by the determining unit, are based on one root sequence, the one root sequence divided into macro and pico sequences;

the indication parameter, sent by the sending unit, comprises a starting point identity of the one root sequence and length information of the one root sequence, wherein the length information of the one root sequence is an ending point identity of the one root sequence or the number of sequences comprised in the one root sequence.

22. The base station according to claim 21, wherein K is a total number of PRACH sequences included in the PRACH sequence group such that k1+k2+k3=N, k4+k5+k6=K-N, K and N are positive integers and K>

N;

the indication parameter, sent by the sending unit, further comprises k1, kx, k4, and ky, wherein kx=k1+k2, ky=k4+k5, wherein k1 is the number of sequences of Group A, defined in a system information block (SIB2) of the macro base station;

kx is the number of contention-based sequences of the macro base station, k4 is the number of sequences of Group A, defined in a system information block (SIB2) of the pico base station; and

ky is the number of contention-based sequences of the pico base station.

23. The base station according to claim 19, wherein the first PRACH sequences to the third PRACH sequences, determined by the determining unit, are used for random access to the macro base station or the pico base station, and the fourth PRACH sequences to the sixth PRACH sequences, determined by the determining unit, are used for random access to the pico base station.

20. A base station, comprising:

a determining unit, configured to determine a physical random access channel PRACH sequence group used by multiple base stations, wherein the multiple base stations use a same cell identity and comprise a macro base station and at least one pico base station, the PRACH sequence group comprises k1 first PRACH sequences, k2 second PRACH sequences, k3 third PRACH sequences, k4 fourth PRACH sequences, k5 fifth PRACH sequences, and k6 sixth PRACH sequences, wherein k1 and k4 are positive integers, and k2, k3 , k5, and k6 are nonnegative integers; and

a sending unit, configured to send an indication parameter of the PRACH sequence group determined by the determining unit, to a user equipment UE for the UE to randomly access a network, wherein the indication parameter is used for indicating the first PRACH sequences to the sixth PRACH sequences;

wherein the first PRACH sequences and the fourth PRACH sequences, determined by the determining unit, are PRACH sequences of contention-based Group A, the second PRACH sequences and the fifth PRACH sequences are PRACH sequences of contention-based Group B, and the third PRACH sequences and the sixth PRACH sequences are non-contention based PRACH sequences.

24. A user equipment, comprising:

a receiving unit, configured to receive an indication parameter of a physical random access channel PRACH sequence group used by multiple base stations, wherein the multiple base stations use a same cell identity and comprise a macro base station and at least one pico base station, the PRACH sequence group based on two root sequences, a first root sequence associated with the macro base station and a second root sequence associated with the pico base station, and the indication parameter is used for indicating first PRACH sequences to sixth PRACH sequences, wherein the first PRACH sequences to the sixth PRACH sequences are comprised in the PRACH sequence group;

a determining unit, configured to determine, according to the indication parameter received by the receiving unit, that the PRACH sequence group comprises k1 first PRACH sequences, k2 second PRACH sequences, k3 third PRACH sequences, k4 fourth PRACH sequences, k5 fifth PRACH sequences, and k6 sixth PRACH sequences, wherein k1 and k4 are positive integers, and k2, k3, k5, and k6 are nonnegative integers, wherein the first PRACH sequences to the third PRACH sequences are based on the first root sequence and the fourth PRACH sequences to the sixth PRACH sequences are based on the second root sequence; and

a selecting unit, configured to select a PRACH sequence from the PRACH sequence group determined by the determining unit to randomly access a network.

25. The user equipment according to claim 24, wherein the selecting unit is specifically configured to select any of:

the PRACH sequence from the first PRACH sequences or the fourth PRACH sequences to randomly access the network, wherein the selected PRACH sequence is a sequence of contention-based Group A;

the PRACH sequence from the second PRACH sequences or the fifth PRACH sequences to randomly access the network, wherein the selected PRACH sequence is a sequence of contention-based Group B; and

the PRACH sequence from the third PRACH sequences or the sixth PRACH sequences to randomly access the network, wherein the selected PRACH sequence is a non-contention based PRACH sequence.

26. The user equipment according to claim 24, wherein the determining unit is specifically configured to determine any of:

according to a starting point identity of a first root sequence, length information of the first root sequence, a starting point identity of a second root sequence, and length information of the second root sequence which are comprised in the indication parameter, wherein the length information of the first root sequence is an ending point identity of the first root sequence or the number of sequences comprised in the first root sequence; and

the length information of the second root sequence is an ending point identity of the second root sequence or the number of sequences comprised in the second root sequence; and

,

according to a starting point identity of one root sequence and length information of the one root sequence which are comprised in the indication parameter, the first and second root sequences are combined into the one root sequence such that the first PRACH sequences to the sixth PRACH sequences are based on the one root sequence, wherein the length information of the one root sequence is an ending point identity of the one root sequence or the number of sequences comprised in the one root sequence, the one root sequence divided into macro and pica sequences.

27. The user equipment according to claim 26, wherein the determining unit is further configured to determine k1 to k6 according to k1, kx, k4, and ky which are further comprised in the indication parameter, wherein kx=k1+k2, ky=k4+k5, k1+k2+k3=N, k4+k5+k6=K-N, K and N are positive integers and K>

N with K being a total number of PRACH sequences included in the PRACH sequence group, wherein k1 is the number of sequences of Group A, defined in a system information block (SIB2) of the macro base station;

kx is the number of contention-based sequences of the macro base station, k4 is the number of sequences of Group A, defined in a system information block (SIB2) of the pico base station; and

ky is the number of contention-based sequences of the pico base station.

28. A base station, comprising:

a determining unit, configured to determine M physical random access channel PRACH sequence groups used by L groups of base stations, wherein the L groups of base stations use a same cell identity, each PRACH sequence group of the M PRACH sequence groups comprises m1 first PRACH sequences, m2 second PRACH sequences, and m3 third PRACH sequences, M and L are positive integers and 1<

M<

L, m1 is a positive integer, and m2 and m3 are nonnegative integers, the M PRACH sequence groups multiplexed in the L groups of base stations according to geographic locations of the L groups of base stations; and

a sending unit, configured to send an indication parameter of the PRACH sequence group determined by the determining unit to a user equipment UE for the UE to randomly access a network, wherein the indication parameter is used for indicating the first PRACH sequences to the third PRACH sequences, wherein the first PRACH sequences to the third PRACH sequences are comprised in the M PRACH sequences.

29. The base station according to claim 28, wherein the determining unit is specifically configured to determine any of:

that the M PRACH sequence groups are based on one root sequence, and the indication parameter sent by the sending unit comprises a starting point identity of the root sequence and length information of the root sequence; and

,

that the M PRACH sequence groups are based on M root sequences, and the indication parameter sent by the sending unit comprises starting point identities of the M root sequences and length information of the M root sequences,

wherein the length information of the root sequence is an ending point identity of the root sequence or the number of sequences comprised in the root sequence.

30. The base station according to claim 29, wherein the indication parameter sent by the sending unit further comprises m1 and mx, wherein mx=m1+m2, m1 is the number of sequences of Group A, defined in a system information block (SIB2);

and mx is the number of contention-based sequences.

31. The base station according to claim 28, wherein the determining unit is specifically configured to allocate any of:

a PRACH sequence group that comprises more PRACH sequences to a group of base stations that belong to a high contention area and are in the L groups of base stations; and

a PRACH sequence group that comprises fewer PRACH sequences to a group of base stations that belong to a low contention area and are in the L groups of base stations.

32. The base station according to claim 28, wherein the indication parameter sent by the sending unit is further configured to indicate identity information of a base station which corresponds to each PRACH sequence group.

33. A user equipment, comprising:

a receiving unit, configured to receive an indication parameter of M physical random access channel PRACH sequence groups used by L groups of base stations, wherein the L groups of base stations use a same cell identity, and the indication parameter is used for indicating first PRACH sequences to third PRACH sequences, wherein the first PRACH sequences to the third PRACH sequences are comprised in each PRACH sequence group of the M PRACH sequence groups, the M PRACH sequence groups multiplexed in the L groups of base stations according to geographic locations of the L groups of base stations;

a determining unit, configured to determine, according to the indication parameter, that each PRACH sequence group comprises m1 first PRACH sequences, m2 second PRACH sequences, and m3 third PRACH sequences, wherein M and L are positive integers and 1<

M<

L, m1 is a positive integer, and m2 and m3 are nonnegative integers; and

a selecting unit, configured to select a PRACH sequence from the PRACH sequence group to randomly access a network.

34. The user equipment according to claim 33, wherein the determining unit is specifically configured to determine any of:

according to a starting point identity of one root sequence and length information of the root sequence which are comprised in the indication parameter, that the M PRACH sequence groups are based on the root sequence; and

,

according to starting point identities of M root sequences and length information of the M root sequences, that each PRACH sequence group among the M PRACH sequence groups is based on one root sequence among the M root sequences, wherein the starting point identities of the M root sequences and the length information of the M root sequences are comprised in the indication parameter,

wherein the length information of the root sequence is an ending point identity of the root sequence or the number of sequences comprised in the root sequence.

35. The user equipment according to claim 34, wherein the determining unit is further configured to determine m1, m2, and m3 according to ml and mx which are further comprised in the indication parameter, wherein mx=m1+m2, m1 is the number of sequences of Group A, defined in a system information block (SIB2);

and mx is the number of contention-based sequences.