UPLINK TRANSMISSION PARAMETER SELECTION DURING RANDOM ACCESS MESSAGE TRANSMISSION AND RETRANSMISSION

• US 20180176949A1
• Filed: 12/11/2017
• Published: 06/21/2018
• Est. Priority Date: 12/19/2016
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Islam, Muhammad Nazmul, Li, Junyi, Luo, Tao, Nagaraja, Sumeeth
• Granted Patent: US 10,681,727 B2
• Time in Patent Office: Days
• CPC Class Codes: H04B 7/0695 using beam selection
• CPC Class Codes: H04B 7/088 using beam selection
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/242 taking into account path loss
• CPC Class Codes: H04W 52/248 where transmission power control commands are generated based on a path parameter
• CPC Class Codes: H04W 52/325 Power control of control or pilot channels
• CPC Class Codes: H04W 52/48 during retransmission after error or non-acknowledgment
• CPC Class Codes: H04W 52/50 at the moment of starting communication in a multiple access environment
• CPC Class Codes: H04W 72/542 using measured or perceived quality
• CPC Class Codes: H04W 74/002 Transmission of channel access control information
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access

Abstract

Methods, systems, and devices for wireless communication are described for selecting different uplink transmission parameters for transmission or retransmission of a random access message. A user equipment (UE) may transmit or retransmit a random access message such as a layer 2 or layer 3 (L2/L3) message to a base station during a random access procedure. The UE may select a transmission beam, uplink resource or transmission power for the transmission of the L2/L3 message that differ from those used for transmission of a previous random access message. The selection may be based on path loss associated with synchronization signals or previous transmissions. The selection may also be based on a maximum number of retransmissions.

Claims

1. A method for wireless communication, comprising:

identifying a first uplink transmission beam for a random access procedure;

transmitting, at a first uplink transmission power, a random access preamble based at least in part on the first uplink transmission beam;

receiving a random access response message transmitted from a base station in response to the random access preamble;

identifying a second uplink transmission beam;

selecting a second uplink transmission power based at least in part on a path loss associated with the random access procedure and the identified second uplink transmission beam; and

transmitting, to the base station, a connection request based at least in part on the second uplink transmission power and the second uplink transmission beam.

2. The method of claim 1, further comprising:

participating in a beam refinement process during reception of the random access response message, wherein the path loss associated with the random access procedure is determined based at least in part on the beam refinement process.

3. The method of claim 1, further comprising:

receiving, from the base station, multiple synchronization signals, wherein the path loss associated with the random access procedure is determined based at least in part on at least one of the multiple synchronization signals.

4. The method of claim 1, wherein transmitting the connection request is based at least in part on the second uplink transmission beam different from the first uplink transmission beam.

5. The method of claim 1, wherein selecting the second uplink transmission power is based at least in part on a uplink transmission power command conveyed in the random access response message.

6. The method of claim 5, wherein selecting the second uplink transmission power comprises adjusting the transmission power conveyed in the random access response message based at least in part on the path loss.

7. The method of claim 1, wherein selecting the second uplink transmission power is further based at least in part on a retransmission number of the connection request.

8. The method of claim 1, wherein selecting the second uplink transmission power is further based at least in part on a difference between a path loss associated with the random access response message and a path loss associated with transmission of the random access preamble.

9. The method of claim 1, further comprising:

identifying a first uplink transmission resource for transmission of the random access preamble;

selecting, based at least in part on the random access response message, a second uplink transmission resource different from the first uplink transmission resource; and

transmitting the connection request using the second uplink transmission resource.

10. The method of claim 1, further comprising:

receiving, from the base station, multiple synchronization signals, wherein identifying the second uplink transmission beam for the connection request is based at least in part on reception of one or more of the multiple synchronization signals.

11. The method of claim 1, further comprising:

selecting a third uplink transmission beam different than the second uplink transmission beam; and

retransmitting the connection request based at least in part on the third uplink transmission beam.

12. The method of claim 1, further comprising:

receiving, from the base station, a maximum retransmission number; and

retransmitting the connection request based at least in part on the maximum retransmission number.

13. The method of claim 12, wherein the maximum retransmission number is associated with at least one of a total number of retransmission attempts of the connection request or a maximum number of retransmission attempts of the connection request for each of a plurality of uplink transmission powers.

14. The method of claim 1, further comprising:

receiving, from the base station, an indication of one or more uplink transmit parameters for retransmitting the random access preamble or the connection request, wherein the one or more uplink transmit parameters comprise an uplink transmit power, an uplink transmission resource, or a combination.

15. A method for wireless communication, comprising:

transmitting a random access preamble as part of a random access procedure;

receiving a random access response message transmitted from a base station in response to the random access preamble;

identifying a first uplink transmission beam and a first uplink transmission power;

transmitting, to the base station, a connection request based at least in part on the random access response message, the connection request being transmitted using the first uplink transmission beam and at the first uplink transmission power;

identifying a second uplink transmission beam different from the first uplink transmission beam;

selecting a second uplink transmission power based at least in part on a path loss associated with the random access procedure and the identified second uplink transmission beam; and

retransmitting the connection request based at least in part on the second uplink transmission power and the second uplink transmission beam.

16. The method of claim 15, wherein the connection request is retransmitted based at least in part on an absence of a contention resolution message.

17. The method of claim 15, wherein the connection request is retransmitted based at least in part on receiving a retransmission grant from the base station.

18. The method of claim 15, further comprising:

receiving, from the base station, a maximum retransmission number associated with the connection request; and

retransmitting the connection request based at least in part on the maximum retransmission number.

19. The method of claim 18, wherein the maximum retransmission number is associated with at least one of a total number of retransmission attempts of the connection request or a maximum number of retransmission attempts of the connection request for each of a plurality of uplink transmission powers.

20. A method for wireless communication, comprising:

receiving, at a first uplink transmission power and over a first random access resource, a random access preamble transmitted from a user equipment (UE) over a first uplink transmission beam;

transmit a random access response message in response to the random access preamble;

receiving a connection request based at least in part on the random access response message;

transmitting, to the UE, a signal indicating the UE to ramp up transmit power, select a different random access resource, or both; and

receiving at a second uplink transmission power, a second random access resource, or both, the retransmitted random access preamble or connection request based at least in part on an absence of a response to the random access preamble or connection request, wherein the second uplink transmission power is ramped up from the first uplink transmission power, and wherein the retransmission is in accordance with a maximum retransmission number associated with the random access preamble or connection request.

21. An apparatus for wireless communication, comprising:

a processor;

memory in electronic communication with the processor; and

instructions stored in the memory and executable by the processor to cause the apparatus to;

identify a first uplink transmission beam for a random access procedure;

transmit, at a first uplink transmission power, a random access preamble based at least in part on the first uplink transmission beam;

receive a random access response message transmitted from a base station in response to the random access preamble;

identify a second uplink transmission beam;

select a second uplink transmission power based at least in part on a path loss associated with the random access procedure and the identified second uplink transmission beam; and

transmit, to the base station, a connection request based at least in part on the second uplink transmission power and the second uplink transmission beam.

22. The apparatus of claim 21, wherein the instructions are further executable by the processor to cause the apparatus to:

participate in a beam refinement process during reception of the random access response message, wherein the path loss associated with the random access procedure is determined based at least in part on the beam refinement process.

23. The apparatus of claim 21, wherein the instructions are further executable by the processor to cause the apparatus to:

receive, from the base station, multiple synchronization signals, wherein the path loss associated with the random access procedure is determined based at least in part on at least one of the multiple synchronization signals.

24. The apparatus of claim 21, wherein the instructions are further executable by the processor to cause the apparatus to:

transmit the connection request is based at least in part on the second uplink transmission beam different from the first uplink transmission beam.

25. The apparatus of claim 21, wherein the instructions are further executable by the processor to cause the apparatus to:

select the second uplink transmission power is based at least in part on a uplink transmission power command conveyed in the random access response message.

26. The apparatus of claim 21, wherein the instructions are further executable by the processor to cause the apparatus to:

select the second uplink transmission power is further based at least in part on a retransmission number of the connection request.

27. The apparatus of claim 21, wherein the instructions are further executable by the processor to cause the apparatus to:

select the second uplink transmission power is further based at least in part on a difference between a path loss associated with the random access response message and a path loss associated with transmission of the random access preamble.

28. The apparatus of claim 21, wherein the instructions are further executable by the processor to cause the apparatus to:

identify a first uplink transmission resource for transmission of the random access preamble;

select, based at least in part on the random access response message, a second uplink transmission resource different from the first uplink transmission resource; and

transmit the connection request using the second uplink transmission resource.

29. The apparatus of claim 21, wherein the instructions are further executable by the processor to cause the apparatus to:

receive, from the base station, multiple synchronization signals, wherein identifying the second uplink transmission beam for the connection request is based at least in part on reception of one or more of the multiple synchronization signals.

30. The apparatus of claim 21, wherein the instructions are further executable by the processor to cause the apparatus to:

select a third uplink transmission beam different than the second uplink transmission beam; and

retransmit the connection request based at least in part on the third uplink transmission beam.