Random access method and apparatus

• US 8,934,467 B2
• Filed: 12/02/2011
• Issued: 01/13/2015
• Est. Priority Date: 12/02/2010
• Status: Active Grant

• Current Assignee: Datang Mobile Communications Equipment Company Limited (China Information Communication Technology Group Co. Ltd.)
• Original Assignee: Datang Mobile Communications Equipment Company Limited (China Information Communication Technology Group Co. Ltd.)
• Inventors: Xu, Fangli, Zhao, Yali, Liang, Jing
• Primary Examiner(s): Sheikh, Ayaz
• Assistant Examiner(s): AGA, SORI A
• Application Number:
  US13/990,995
• Publication Number:
  US 20130250902A1
• Time in Patent Office: 1,138 Days
• Field of Search: None
• US Class Current: 370/341
• CPC Class Codes: H04W 36/0077 of access information of target access point
• CPC Class Codes: H04W 74/006 in the downlink, i.e. towards the terminal
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access

Abstract

The invention discloses a random access method and apparatus so as to perform random access for a User Equipment (UE) with a plurality of aggregated cells in a carrier aggregation-enabled LTE-A system. The method includes: determining a secondary cell configured for a UE and obtaining random access related parameter preset for the secondary cell; and sending the random access related parameter to the UE to instruct the UE to initiate random access procedure over the secondary cell corresponding to the random access related parameter. The inventive method achieves the purpose of enabling the UE to be synchronized with the network side by performing random access over a specified cell, having the UE maintain uplink synchronization with the network side in the configured secondary cell and ensuring the overall performance of the system.

Claims

1. A random access method, comprising:

determining a secondary cell configured for a UE and obtaining random access related parameter preset for the secondary cell; and

sending the random access related parameter to the UE to instruct the UE to initiate random access procedure over the secondary cell corresponding to the random access related parameter,

wherein sending the random access related parameter to the UP to instruct the UE to initiate the random access procedure over the secondary cell corresponding to the random access related parameter comprises;

instructing the UE to initiate the random access procedure over the secondary cell corresponding to the random access related parameter immediately after sending the random access related parameter to the UE;

or

sending a physical downlink control channel command to the UE after sending the random access related parameter to the UE to instruct the UE to initiate the random access procedure over the secondary cell corresponding to the random access related parameter;

wherein, if the secondary cell is detected to belong to a Timing Advance (TA) group, applying Timing Advance (TA) information preset for the secondary cell in the random access procedure to all cells comprised in the TA group, and maintaining a Time Alignment Timer (TAT) of the TA group with use of the TA information.

2. The method according to claim 1, wherein the random access related parameter comprises one or any combination of common information element, dedicated information element and newly defined information element for indicating that the UE is allowed to initiate random access procedure over the secondary cell corresponding to the newly defined information element.

3. The method according to claim 1, wherein the method further comprises:

instructing the UE to determine the secondary cell configured with the random access related parameter and to set the secondary cell to be in an active status all the time from being added until being deleted;

or

the method further comprises;

instructing the UE to determine the secondary cell configured with the random access related parameter, to set the secondary cell to an active status immediately after being added, and to deactivate the secondary cell upon detection of uplink out-of-synchronization of Time Alignment Timer (TAT) of the secondary cell;

or

the method further comprises;

instructing the UE to determine the secondary cell configured with the random access related parameter, to set the secondary cell to an active status before random access is initiated, and to deactivate the secondary cell upon detection of uplink out-of-synchronization of TAT of the secondary cell.

4. The method according to claim 3, wherein if uplink out-of-synchronization of TAT of the secondary cell is detected and the UE is instructed to deactivate the secondary cell, then the method further comprises the step of instructing the UE in physical downlink control channel signaling to initiate random access procedure over the secondary cell.

5. The method according to claim 2, wherein the method further comprises:

instructing the UE to determine the secondary cell configured with the random access related parameter and to set the secondary cell to be in an active status all the time from being added until being deleted;

or

the method further comprises;

instructing the UE to determine the secondary cell configured with the random access related parameter, to set the secondary cell to an active status immediately after being added, and to deactivate the secondary cell upon detection of uplink out-of-synchronization of Time Alignment Timer (TAT) of the secondary cell;

or

the method further comprises;

instructing the UE to determine the secondary cell configured with the random access related parameter, to set the secondary cell to an active status before random access is initiated, and to deactivate the secondary cell upon detection of uplink out-of-synchronization of TAT of the secondary cell.

6. A random access method, comprising:

receiving random access related parameter. sent from network side, preset for a secondary cell configured locally; and

initiating random access procedure over the secondary cell corresponding to the random access related parameter,

wherein initiating random access procedure over the secondary cell corresponding to the random access related parameter comprises;

initiating the random access procedure over the secondary cell corresponding to the random access related parameter immediately upon reception of the random access related parameter;

or

initiating the random access procedure over the secondary cell corresponding to the random access related parameter upon reception of a physical downlink control channel command after receiving the random access related parameter;

wherein, if the secondary cell is detected to belong to a Timing Advance (TAT) group, then applying Timing Advance (TA) information obtained by the secondary cell in the random access procedure to all cells comprised in the TA group, and maintaining a Time Alignment Timer (TAT) of the TA group with use of the TA information.

7. The method according to claim 6, wherein the random access related parameter comprises one or any combination of common information element, dedicated information element and newly defined information element for indicating that the UE is allowed to initiate random access procedure over the secondary cell corresponding to the newly defined information element.

8. The method according to claim 6, wherein the method further comprises:

determining the secondary cell configured with the random access related parameter and setting the secondary cell to be in an active status all the time from being added until being deleted;

or

the method further comprises;

determining the secondary cell configured with the random access related parameter, setting the secondary cell to an active status immediately after being added, and deactivating the secondary cell upon detection of uplink out-of-synchronization of Time Alignment Timer (TAT) of the secondary cell;

or

the method further comprises;

determining the secondary cell configured with the random access related parameter, setting the secondary cell to an active status before random access is initiated, and deactivating the secondary cell upon detection of uplink out-of-synchronization of TAT of the secondary cell.

9. The method according to claim 8, wherein if uplink out-of-synchronization of TAT of the secondary cell is detected and the secondary cell is deactivated, then the method further comprises the step of initiating random access procedure over the secondary cell upon reception of physical downlink control channel signaling.

10. The method according to claim 7, wherein the method further comprises:

determining the secondary cell configured with the random access related parameter and setting the secondary cell to he in an active status all the time from being added until being deleted;

or

determining the secondary cell configured with the random access related parameter, setting the secondary cell to an active status immediately after being added, and deactivating the secondary cell upon detection of uplink out-of-synchronization of Time Alignment Timer (TAT) of the secondary cell;

or

determining the secondary cell configured with the random access related parameter, setting the secondary cell to an active status before random access is initiated, and deactivating the secondary cell upon detection of uplink out-of-synchronization of TAT of the secondary cell.

11. A random access apparatus, comprising:

an obtaining unit configured to determine a secondary cell configured for a UE and to obtain random access related parameter preset for the secondary cell; and

a communicating unit configured to send the random access related parameter to the UE to instruct the UE to initiate random access procedure over the secondary cell corresponding to the random access related parameter,

wherein the communicating unit instructs the UE to initiate the random access procedure over the secondary cell corresponding to the random access related parameter immediately after sending the random access related parameter to the UE;

or sends a physical downlink control channel command to the UE after sending the random access related parameter to the UE to instruct the UE to initiate the random access procedure over the secondary cell corresponding to the random access related parameter;

wherein, if the secondary cell is detected to belong to a Timing Advance (TA) group, then the communicating unit applies Timing Advance (TA) information preset for the secondary cell in the random access procedure to all the cells comprised in the TA group, and maintains a Time Alignment Timer (TAT) of the TA group with use of the TA information.

12. The apparatus according to claim 11, wherein the communicating unit instructs the UE to determine the secondary cell configured with the random access related parameter and to set the secondary cell to be in an active status all the time from being added until being deleted;

or

the communicating unit instructs the UE to determine the secondary cell configured with the random access related parameter, to set the secondary cell to an active status immediately after being added, and to deactivate the secondary cell upon detection of uplink out-of-synchronization of Time Alignment Timer (TAT) of the secondary cell;

or

the communicating unit instructs the UE to determine the secondary cell configured with the random access related parameter, to set the secondary cell to an active status before random access is initiated, and to deactivate the secondary cell upon detection of uplink out-of-synchronization of TAT of the secondary cell.

13. The apparatus according to claim 12, wherein if uplink out-of-synchronization of TAT of the secondary cell is detected and the UE is instructed to deactivate the secondary cell, then the communicating unit instructs the UE in physical downlink control channel signaling in a subsequent flow to initiate the random access procedure over the secondary cell.

14. A random access apparatus, comprising:

a communicating unit configured to receive random access related parameter, sent from network side, preset for a secondary cell configured locally; and

a processing unit configured to initiate random access procedure over the secondary cell corresponding to the random access related parameter,

wherein the processing unit initiates the random access procedure over the secondary cell corresponding to the random access related parameter immediately after the communicating unit receives the random access related parameter;

or

the processing unit initiates the random access procedure over the secondary cell corresponding to the random access related parameter when the communicating unit receives a physical downlink control channel command after receiving the random access related parameter;

wherein, if the communicating unit detects the secondary cell to belong to a Timing Advance (TA) group, then the processing unit applies Timing Advance (TA) information obtained by the secondary cell in the random access procedure to all the cells comprised in the TA group, and maintains a Time Alignment Timer (TAT) of the TA group with use of the TA information.

15. The apparatus according to claim 14, wherein the communicating unit determines the secondary cell configured with the random access related parameter and set the secondary cell to be in an active status all the time from being added until being deleted;

or

the communicating unit determines the secondary cell configured with the random access related parameter, sets the secondary cell to an active status immediately after being added, and deactivates the secondary cell upon detection of uplink out-of-synchronization of Time Alignment Timer (TAT) of the secondary cell;

or

the communicating unit determines the secondary cell configured with the random access related parameter, sets the secondary cell to an active status before random access is initiated, and deactivates the secondary cell upon detection of uplink out-of-synchronization of TAT of the secondary cell.

16. The apparatus according to claim 15, wherein if the communicating unit detects uplink out-of-synchronization of TAT of the secondary cell and deactivates the secondary cell, then the processing unit initiates random access procedure over the secondary cell upon reception of physical downlink control channel signaling in a subsequent flow.