Random access method and apparatus based on multiple uplink timing advances

• US 9,883,534 B2
• Filed: 02/17/2012
• Issued: 01/30/2018
• Est. Priority Date: 03/31/2011
• Status: Active Grant

• Current Assignee: Datang Mobile Communications Equipment Company Limited (China Information Communication Technology Group Co. Ltd.)
• Original Assignee: China Academy of Telecom Technology (China Information Communication Technology Group Co. Ltd.)
• Inventors: Chen, Li, Xu, Fangli, Zhao, Yali, Liu, Jiamin
• Primary Examiner(s): Mesfin, Yemane
• Assistant Examiner(s): Elmejjarmi, Abdelillah
• Application Number:
  US14/008,482
• Publication Number:
  US 20140044074A1
• Time in Patent Office: 2,174 Days
• CPC Class Codes: H04W 56/0045 compensating for timing error by altering transmission time
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access

Abstract

Disclosed are a random access method and apparatus based on multiple uplink timing advances. The method includes: when acquiring that a user equipment has multiple uplink timing advances, initiating, by a network side, for the user equipment a random access on a designated carrier of a secondary cell. According to the examples, random access in the SCell can be realized in scenarios that multi-TA is maintained.

Claims

1. A method for performing random access based on multiple uplink timing advances, comprising:

in response to acquiring that a user equipment (UE) has multiple uplink timing advances, initiating, by a network side, a random access on a designated carrier of a secondary cell (SCell) for the UE;

wherein initiating the random access on the designated carrier of the SCell for the UE comprises;

determining, by the network side, a carrier for transmitting a random access resource allocation message Msg0 according to whether cross-carrier scheduling is configured for the designated carrier on which the random access is to be initiated;

transmitting, by the network side, the random access resource allocation message Msg0 on a scheduling carrier configured in response to determining that cross-carrier scheduling is configured for a designated carrier on which a random access of a secondary cell (SCell) is to be initiated for a user equipment (UE); and

transmitting, by the network side, the Msg0 on a downlink carrier of the SCell in which the random access is to be initiated in response to determining that the cross-carrier scheduling is not configured for the designated carrier on which the random access is to be initiated; and

wherein initiating the random access on the designated carrier of the SCell for the UE further comprises;

transmitting, by the network side, a random access response message (Msg2) Media Access Control (MAC) Protocol Data Unit (PDU) on the downlink carrier of the SCell in which the random access is initiated;

or

transmitting, by the network side, an Msg2 MAC PDU on the same carrier as a Msg2 scheduling command.

2. The method of claim 1, wherein transmitting the Msg2 MAC PDU on the same carrier as the Msg2 scheduling command comprises:

transmitting, by the network side, the Msg2 scheduling command in a Primary Cell (PCell); and

transmitting, by the network side, the Msg2 MAC PDU on a downlink carrier of the PCell;

wherein transmitting the Msg2 MAC PDU on the downlink carrier of the SCell in which the random access is initiated comprises;

transmitting, by the network side, the Msg2 MAC PDU on the downlink carrier of the SCell in which the random access is initiated in default or indicated by a Carrier Indication Field (CIF) in the Msg2 scheduling command.

3. A method for performing random access based on multiple uplink timing advances, comprising:

in response to a user equipment (UE) having multiple uplink timing advances, receiving, by the UE, a random access resource allocation message Msg0 on a scheduling carrier configured in response to cross-carrier scheduling being configured for the designated carrier on which the random access is to be initiated for the UE;

receiving, by the UE, the Msg0 on a downlink carrier of the SCell in which the random access is to be initiated in response to the cross-carrier scheduling being not configured for the designated carrier on which the random access is to be initiated; and

transmitting, by the UE, a random access preamble transmitting message Msg1 on a Physical Random Access Channel (PRACH) resource of the designated carrier according to an indication of the Msg0;

wherein performing the random access on the designated carrier of the SCell according to the indication of the network side comprises;

receiving, by the UE, a random access response message Msg2 scheduling command on a carrier on which the network side transmits the Msg0, wherein an Msg2 MAC PDU is transmitted on a downlink carrier of the SCell on which the random access is performed, or an Msg2 MAC PDU is transmitted on the same carrier as the Msg2 scheduling command;

wherein in response to receiving the random access response message Msg2 scheduling command from the carrier on which the network side transmits the Msg0, the Msg2 MAC PDU is transmitted on the downlink carrier of the SCell on which the random access is performed, or the Msg2 MAC PDU is transmitted on the same carrier as the Msg2 scheduling command.

4. The method of claim 3, further comprising:

selecting randomly, by the UE, from preambles used for a contention-based random access to transmit the Msg1 on a PRACH resource configured on the SCell if the Msg0 indicates the contention-based random access.

5. The method of claim 3, wherein receiving the Msg2 scheduling command on the carrier on which the network side transmits Msg0 comprises:

receiving, by the UE, the Msg2 scheduling command in a Primary Cell (PCell) and receiving the Msg2 MAC PDU in the PCell if the Msg2 MAC PDU is transmitted on the same carrier as the Msg2 scheduling command;

receiving, by the UE, the Msg2 MAC PDU on the downlink carrier of the SCell in which the random access is performed according to a Carrier Indication Field (CIF) in the Msg2 scheduling command or in default if the Msg2 MAC PDU is transmitted on the downlink carrier of the SCell on which the random access is performed if the Msg2 MAC PDU is transmitted on the downlink carrier of the SCell on which the Msg1 is transmitted.

6. The method of claim 3, wherein performing the random access on the designated carrier of the SCell according to the indication of the network side comprises:

transmitting, by the UE, an uplink transmission message Msg3 scheduled by the random access on an uplink carrier of the SCell in which random access is performed according to an UL grant in the Msg2 MAC PDU and applying an uplink timing advance (TA) value in the Msg2 if there is uplink resource allocation for the UE.

7. The method of claim 6, wherein the TA value takes a downlink carrier of the PCell as a reference downlink carrier for TA value estimation, or takes the downlink carrier which belongs to the same SCell as the uplink carrier in which the random access is performed as the reference downlink carrier.

8. A network side device comprising:

a processor for executing instructions stored in a non-transitory machine readable storage medium to execute;

in response to acquiring that a user equipment (UE) has multiple uplink timing advances, initiating, by a network side, a random access on a designated carrier of a secondary cell (SCell) for the UE;

wherein initiating the random access on the designated carrier of the SCell for the UE comprises;

determining, by the network side, a carrier for transmitting a random access resource allocation message Msg0 according to whether cross-carrier scheduling is configured for the designated carrier on which the random access is to be initiated; and

transmitting the random access resource allocation message Msg0 on a scheduling carrier configured in response to determining that cross-carrier scheduling is configured for a designated carrier on which a random access of a secondary cell (SCell) is to be initiated for a user equipment (UE), transmitting the Msg0 on a downlink carrier of the SCell in which the random access is to be initiated in response to determining that the cross-carrier scheduling is not configured for the designated carrier on which the random access is to be initiated; and

initiating the random access on the designated carrier of the SCell for the UE further comprises;

transmitting a random access response message (Msg2) Media Access Control (MAC) Protocol Data Unit (PDU) on the downlink carrier of the SCell on which the random access is initiated, or transmitting an Msg2 MAC PDU on the same carrier as a Msg2 scheduling command.

9. A user equipment (UE), comprising:

a processor for executing instructions stored in a non-transitory machine readable storage medium to execute the following procedure, comprising;

determine that a UE has multiple uplink timing advances; and

receive a random access resource allocation message Msg0 on a scheduling carrier configured in response to cross-carrier scheduling being configured for the designated carrier on which the random access is to be initiated for the UE, receive the Msg0 on a downlink carrier of the SCell in which the random access is to be initiated in response to the cross-carrier scheduling being not configured for the designated carrier on which the random access is to be initiated, transmit a random access preamble transmitting message Msg1 on a Physical Random Access Channel (PRACH) resource of the designated carrier according to an indication of the Msg0;

wherein performing the random access on the designated carrier of the SCell according to the indication of the network side comprises;

receiving, by the UE, a random access response message Msg2 scheduling command on a carrier on which the network side transmits the Msg0, wherein an Msg2 MAC PDU is transmitted on a downlink carrier of the SCell on which the random access is performed, or an Msg2 MAC PDU is transmitted on the same carrier as the Msg2 scheduling command; and

wherein in response to receiving the random access response message Msg2 scheduling command from the carrier on which the network side transmits the Msg0, the Msg2 MAC PDU is transmitted on the downlink carrier of the SCell on which the random access is performed, or the Msg2 MAC PDU is transmitted on the same carrier as the Msg2 scheduling command.

10. The UE of claim 9, wherein the instructions are further to execute the following procedure:

select randomly from preambles used for a contention-based random access to transmit the Msg1 on PRACH resources configured on the SCell if the Msg0 indicates the contention-based random access.

11. The UE of claim 9, wherein if a random access response message Msg2 scheduling command is received from the carrier on which the network side transmits Msg0;

a Msg2 MAC PDU is transmitted on a downlink carrier of the SCell on which the random access is performed, or an Msg2 MAC PDU is transmitted on the same carrier as the Msg2 scheduling command.