Random access response message transmission

Patent metadata

Field	Value
Publication number	US-10772123-B2
Application number	US-201515561937-A
Country	US
Kind code	B2
Filing date	Apr 8, 2015
Priority date	Apr 8, 2015
Publication date	Sep 8, 2020
Grant date	Sep 8, 2020

Abstract

Systems, methods, apparatuses, and computer program products for random access procedure are provided. One method includes selecting, by a user equipment, a subframe for a first transmission of a preamble based on a configuration broadcast by an evolved node B (eNB). The method may also include repeating the preamble within a preamble repetition period based on a configuration broadcast by the eNB.

First claim

We claim:

1. A method, comprising:
selecting, by a user equipment, a subframe for a first transmission of a preamble based on a configuration broadcast by an evolved node B; and
repeating transmission of the preamble within a preamble repetition period based on a configuration received from a broadcast by the evolved node B;
wherein the configuration for the preamble repetition period comprises one or more of number of repetitions within the repetition period and interval between the preamble repetitions;
after completing a required number of preamble repetitions within the preamble repetition period, starting monitoring enhanced physical downlink control channel transmission from a subframe that is k subframes after the completion of the preamble transmission for receiving a random access response message, where k is a parameter received through broadcasted system information;
wherein the enhanced physical downlink control channel is identified by a random access radio network temporary identifier (RA-RNTI) according to the following equation:
RA-RNTI=1 +SFN _PRACH/ R _ R _Period+10* f _id,

 where SFN_PRACH is the system frame number of the frame at which physical random access channel occasion occurs, R_R_Period is the preamble repetition period, and f_id is the number of physical random access channel regions that map to the same enhanced physical downlink control channel region.

2. The method according to claim 1 , wherein the configuration for the first transmission comprises one or more of preamble repetition period or subframe offset.

3. The method according to claim 1 , further comprising, after completing a required number of preamble repetitions within the preamble repetition period, starting monitoring enhanced physical downlink control channel (EPDCCH) transmission from the nearest EPDCCH occasion after the completion of the preamble transmission for receiving a random access response (RAR) message.

4. An apparatus, comprising:
at least one processor; and
at least one memory comprising computer program code,
the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus at least to
select a subframe for a first transmission of a preamble based on a configuration broadcast by an evolved node B; and
repeat transmission of the preamble within a preamble repetition period based on a configuration received from a broadcast by the evolved node B;
wherein the configuration for the preamble repetition period comprises one or more of number of repetitions within the repetition period and interval between the preamble repetitions;
after completing a required number of preamble repetitions within the preamble repetition period, starting monitoring enhanced physical downlink control channel transmission from a subframe that is k subframes after the completion of the preamble transmission for receiving a random access response message, where k is a parameter received through broadcasted by system information;
wherein the enhanced physical downlink control channel is identified by a random access radio network temporary identifier (RA-RNTI) according to the following equation:
RA-RNTI=1 +SFN _PRACH/ R _ R _Period+10* f _id,

 where SFN_PRACH is the system frame number of the frame at which physical random access channel occasion occurs, R_R_Period is the preamble repetition period, and f_id is the number of physical random access channel regions that map to the same enhanced physical downlink control channel region.

5. The apparatus according to claim 4 , wherein the configuration for the first transmission comprises one or more of preamble repetition period or subframe offset.

6. The apparatus according to claim 4 , wherein the at least one memory and computer program code are further configured to, with the at least one processor, cause the apparatus at least to select the subframe as the physical random access channel (PRACH) occasion for sending the first transmission of the preamble, and wherein the PRACH occasion satisfies the following equations:
R _ R _Period>=CEILING(repetition number of preamble* R _Interval/10,1), and
R _ SFN mod R _ R _Period= R _ O _Offset,
where R_SFN is the system frame number of the frame where the PRACH occasion occurs, R_R_Period is the preamble repetition period, R_O_Offset is the PRACH occasion offset, and R_interval is the interval between the preamble repetitions.

7. An apparatus, comprising:
at least one processor; and
at least one memory comprising computer program code,
the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus at least to
detect a potential preamble only from physical random access channel occasion; and
combine repetitions of the preamble within a repetition period based on a pattern broadcast by the apparatus functioning as a network node;
wherein the network node determines a configuration for the preamble repetition period and the configuration for the preamble period comprises one or more of number of repetitions within the repetition period and interval between the preamble repetitions;
wherein after a required number of preamble repetitions within the preamble repetition period is completed, provide an enhanced physical downlink control channel transmission for monitoring from a subframe that is k subframes after the completion of the preamble transmission for receiving a random access response message, where k is a parameter received through broadcasted by system information;
wherein the enhanced physical downlink control channel is identified by a random access radio network temporary identifier (RA-RNTI) according to the following equation:
RA-RNTI=1 +SFN _PRACH/ R _ R _Period+10* f _id,

 where SFN_PRACH is the system frame number of the frame at which physical random access channel occasion occurs, R_R_Period is the preamble repetition period, and f_id is the number of physical random access channel regions that map to the same enhanced physical downlink control channel region.

8. The apparatus according to claim 7 , wherein the at least one memory and computer program code are configured to, with the at least one processor, cause the apparatus at least to, when multiple physical random access channel (PRACH) occasions are mapped to a same enhanced physical downlink control channel (EPDCCH) occasion, separate EPDCCH identified by different random access radio network temporary identifier (RA-RNTI) according to the following equation:
RA-RNTI=1+ L _id+10* f _id, such that 1<= L _id<= EP _ R _Period/ R _ R _Period,
where R_R_Period is preamble repetition period, EP_R_Period is EPDCCH repetition period, f_id is the number of PRACH regions that map to the same EPDCCH region, and L_id is the index of PRACH occasions that map to the same EPDCCH region.

9. The apparatus according to claim 7 , wherein the at least one memory and computer program code are configured to, with the at least one processor, cause the apparatus at least to, when there is any overlap among the enhanced physical downlink control channel (EPDCCH) transmissions corresponding to the preamble transmission of different user equipment, separate EPDCCH identified by different random access radio network temporary identifier (RA-RNTI), and
wherein the RA-RNTI is calculated according to the following equation:
RA-RNTI=1 +SFN _PRACH/ R _ R _Period+10* f _id,

where SFN_PRACH is the system frame number of the frame at which PRACH occasion occurs, R_R_Period is the preamble repetition period (n1, n2, . . . nX) (n1=1 frame, n2=2 frames, . . . nX=X frames), and f_id is the number of physical random access channel (PRACH) regions t

Assignees

• Nokia Solutions & Networks Oy

Inventors

• Zhang yuan tao
• Zhang yan ji
• Ratasuk Rapeepat
• Mangalvedhe Nitin

Classifications

• H04W74/0833

  Random access procedures, e.g. with 4-step access · CPC title

• H04W74/004 Primary

  in the uplink, i.e. towards network · CPC title

• H04W72/1268

  of uplink data flows · CPC title

• H04L1/1887 Primary

  Scheduling and prioritising arrangements · CPC title

• H04L5/0053

  Allocation of signalling, i.e. of overhead other than pilot signals · CPC title