METHOD AND APPARATUS FOR RANDOM ACCESS IN MULTICARRIER WIRELESS COMMUNICATIONS

• US 20100296467A1
• Filed: 04/23/2010
• Published: 11/25/2010
• Est. Priority Date: 04/23/2009
• Status: Active Grant

• Current Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Original Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Inventors: Wang, Peter S., Marinier, Paul, Terry, Stephen E., Dennean, Charles A., Wang, Jin, Zhang, Guodong, Gauvreau, Jean-Louis, Haghighat, Afshin, Bala, Erdem, Pelletier, Ghyslain, Somasundaram, Shankar
• Granted Patent: US 8,767,585 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 74/002 Transmission of channel access control information
• CPC Class Codes: H04W 74/004 in the uplink, i.e. towards network
• 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

Methods and apparatus for random access in multicarrier wireless communications are disclosed. Methods and apparatus are provided for physical random access channel (PRACH) resource signaling, PRACH resource handling, preamble and PRACH resource selection, random access response (RAR) reception, preamble retransmission, and transmission and reception of subsequent messages. A method for maintaining an allowed multicarrier uplink (UL) random access channel (RACH) configuration set by adding an UL carrier to the allowed RACH configuration set provided that a triggering event occurs and performing a random access (RA) procedure using the allowed RACH configuration set. A method for sending data in multicarrier wireless communications by determining a set of available UL carriers and selecting an UL carrier from the set of available UL carriers.

Claims

1. A method for maintaining an allowed multicarrier uplink (UL) random access channel (RACH) configuration set, comprising:

adding an UL carrier to an allowed RACH configuration set, on a condition that a triggering event occurs; and

performing a random access (RA) procedure using the allowed RACH configuration set.

2. The method according to claim 1, wherein the adding includes adding a physical random access channel (PRACH)/RACH configuration to the allowed RACH configuration set.

3. The method according to claim 1, wherein the performing includes:

selecting a physical random access channel (PRACH) resource from a set of available PRACH resources; and

determining the next available subframe containing an allowed PRACH resource within a set of all available PRACH resources given by a set of parameters that indicate PRACH resources on at least one UL frequency.

4. A method for sending data, comprising:

determining a set of available uplink (UL) carriers; and

on a condition that more than one UL carrier exists, selecting an UL carrier from the set of available UL carriers based on estimated path loss.

5. The method according to claim 4, wherein the selecting includes selecting an UL carrier based on estimated path loss differences between a cell and a neighboring cell.

6. A method for initial random access (RA) transmission using a multicarrier uplink (UL) random access channel (RACH) scheme, the method comprising:

selecting an UL carrier from a plurality of UL carriers;

selecting a random access preamble group based on the selected UL carrier; and

selecting a random access preamble within the selected random access preamble group.

7. The method according to claim 6, wherein the selecting an UL carrier from a plurality of UL carriers includes:

dividing available UL component carriers (CCs) into a first carrier set and a second carrier set;

on a condition that the first carrier set is empty, selecting one UL carrier within the second carrier set; and

on a condition that the first carrier set is not empty, selecting one UL carrier within the first carrier set.

8. The method according to claim 6, wherein:

the selecting an UL carrier from a plurality of UL carriers includes selecting one UL carrier among UL component carriers (CCs) based on path loss; and

the selecting a random access preamble within the selected random access preamble group includes randomly selecting a random access preamble within the selected random access preamble group.

9. The method according to claim 6, wherein:

the selecting an UL carrier from a plurality of UL carriers includes selecting one UL carrier among UL component carriers (CCs) based on Pmax; and

the selecting a random access preamble within the selected random access preamble group includes randomly selecting a random access preamble within the selected random access preamble group.

10. A method for transmitting a random access response (RAR) using a multicarrier uplink (UL) random access channel (RACH) scheme, the method comprising:

determining a downlink (DL) carrier for RAR transmission;

computing a random access radio network temporary identifier (RA-RNTI) associated with the RAR; and

transmitting the RAR including the RA-RNTI.

11. The method according to claim 10, wherein the computing includes:

on a condition that the RAR is to be transmitted on a known DL primary component carrier (PCC);

configuring a RAR window such that RAR windows associated with different UL carriers do not overlap, on a condition that RAR windows may not overlap; and

computing RA-RNTI as a function of the UL carrier on which a random access (RA) preamble was transmitted and the UL carrier for which a RAR is mapped on a DL PCC.

12. A method performed at a wireless transmit/receive unit (WTRU) for determining at least one downlink (DL) carrier on which a random access response (RAR) should be received, the method comprising:

monitoring at least one physical downlink control channel (PDCCH) in a common search space on at least one DL carrier for a random access radio network temporary identifier (RA-RNTI) value that corresponds to the WTRU; and

receiving a RAR identified by the RA-RNTI.

13. A WTRU configured to maintain an allowed multicarrier uplink (UL) random access channel (RACH) configuration set, the WTRU comprising:

a processor and transmitter configured to;

determine whether to add an UL carrier to an allowed RACH configuration set on a condition that a triggering event occurs;

add the UL carrier to the allowed RACH configuration set; and

perform a random access (RA) procedure using the allowed RACH configuration set.

14. The WTRU according to claim 13, wherein the processor is further configured to add an UL carrier to the allowed RACH configuration set by adding a physical random access channel (PRACH)/RACH configuration to the allowed RACH configuration set.

15. A wireless transmit/receive unit (WTRU) configured to perform multicarrier uplink (UL) communications, the WTRU comprising:

a processor and transmitter configured to;

determine available UL carriers; and

on a condition that more than one UL carrier exists, select a UL carrier based on estimated path loss.