Selecting a random access procedure type in a wireless system

Patent metadata

Field	Value
Publication number	US-11653393-B2
Application number	US-202217864047-A
Country	US
Kind code	B2
Filing date	Jul 13, 2022
Priority date	Mar 28, 2019
Publication date	May 16, 2023
Grant date	May 16, 2023

Abstract

A wireless device receives radio resource control message(s) from a base station indicating random access resources of an uplink bandwidth part of a cell, that comprises two-step random access resources. The wireless device may determine, while the two-step random access type and a four-step random access type are available for transmitting a preamble, that the two-step random access resources comprise contention-free two-step random access resources. The wireless device may also select from among the two-step random access type and the four-step random access type, the two-step random access type. The wireless device may then transmit a preamble to the base station using the two-step random access resources, based on the two-step random access type.

First claim

The invention claimed is:

1. A method comprising:
receiving, by a wireless device from a base station, one or more radio resource control (RRC) messages indicating random access resources, the random access resources comprising two-step random access resources, of a two-step random access type, of an uplink bandwidth part (UL BWP);
determining, while the two-step random access type and a four-step random access type are available for transmitting a preamble, that the two-step random access resources comprise contention-free two-step random access resources;
selecting, based on the determining that the two-step random access resources comprise the contention-free two-step random access resources, the two-step random access type from among the two-step random access type and the four-step random access type; and
transmitting, based on the two-step random access type, the preamble using the contention-free two-step random access resources.

2. The method of claim 1 , wherein the one or more RRC messages further indicate a threshold for a received signal strength of at least one downlink reference signal.

3. The method of claim 2 , wherein the selecting is further based on the received signal strength of the at least one downlink reference signal being below or equal to the threshold.

4. The method of claim 1 , wherein the UL BWP is an active UL BWP of a cell.

5. The method of claim 1 , further comprising initiating a random access procedure on the UL BWP of a cell.

6. The method of claim 1 , further comprising selecting a downlink reference signal at least based on the two-step random access resources, wherein the preamble is associated with the downlink reference signal.

7. The method of claim 6 , wherein the two-step random access resources comprise:
at least one random access channel occasion, corresponding to the downlink reference signal, for the transmitting the preamble; and
at least one uplink grant associated with the preamble and the at least one random access channel occasion.

8. The method of claim 7 , further comprising transmitting at least one transport block to the base station using the at least one uplink grant.

9. The method of claim 1 , wherein the two-step random access resources of the UL BWP further comprise contention-based two-step random access resources.

10. The method of claim 1 , wherein the one or more RRC messages further indicate a reconfiguration with synchronization for a handover of the wireless device.

11. A wireless device comprising one or more processors and memory storing instructions that, when executed by the one or more processors, cause the wireless device to:
receive, from a base station, one or more radio resource control (RRC) messages indicating random access resources, the random access resources comprising two-step random access resources, of a two-step random access type, of an uplink bandwidth part (UL BWP);
determine, while the two-step random access type and a four-step random access type are available for transmitting a preamble, that the two-step random access resources comprise contention-free two-step random access resources;
select, based on the determining that the two-step random access resources comprise the contention-free two-step random access resources, the two-step random access type from among the two-step random access type and the four-step random access type; and
transmit, based on the two-step random access type, the preamble using the contention-free two-step random access resources.

12. The wireless device of claim 11 , wherein the one or more RRC messages further indicate a threshold for a received signal strength of at least one downlink reference signal.

13. The wireless device of claim 12 , wherein the instructions further cause the wireless device to select the two-step random access type based on the received signal strength of the at least one downlink reference signal being below or equal to the threshold.

14. The wireless device of claim 11 , wherein the UL BWP is an active UL BWP of a cell.

15. The wireless device of claim 11 , wherein the instructions further cause the wireless device to initiate a random access procedure on the UL BWP of a cell.

16. The wireless device of claim 11 , wherein the instructions further cause the wireless device to select a downlink reference signal at least based on the two-step random access resources, wherein the preamble is associated with the downlink reference signal.

17. The wireless device of claim 16 , wherein the two-step random access resources comprise:
at least one random access channel occasion, corresponding to the downlink reference signal, for transmitting the preamble; and
at least one uplink grant associated with the preamble and the at least one random access channel occasion.

18. The wireless device of claim 17 , wherein the instructions further cause the wireless device to transmit at least one transport block to the base station using the at least one uplink grant.

19. The wireless device of claim 11 , wherein the two-step random access resources of the UL BWP further comprise contention-based two-step random access resources.

20. A system comprising:
a base station comprising one or more first processors and first memory storing instructions that, when executed by the one or more first processors, cause the base station to:
transmit, to a wireless device, one or more radio resource control (RRC) messages indicating random access resources, the random access resources comprising two-step random access resources, of a two-step random access type, of an uplink bandwidth part (UL BWP), wherein the two-step random access resources comprise contention-free two-step random access resources; and
receive a preamble using the two-step random access resources; and

the wireless device comprising one or more second processors and second memory storing instructions that, when executed by the one or more second processors, cause the wireless device to:
receive the one or more RRC messages;
determine, while the two-step random access type and a four-step random access type are available for transmitting a preamble, that the two-step random access resources comprise the contention-free two-step random access resources;
select, based on the determining that the two-step random access resources comprise the contention-free two-step random access resources, the two-step random access type from among the two-step random access type and the four-step random access type; and
transmit, based on the two-step random access type, the preamble to the base station using the contention-free two-step random access resources.

Assignees

• Ofinno Llc

Inventors

• Rastegardoost Nazanin
• Dinan Esmael Hejazi
• Jeon Hyoungsuk
• Yi Yunjung
• Park Kyungmin
• Zhou Hua

Classifications

• H04L5/0048 Primary

  Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091) · CPC title

• H04W74/0836

  with 2-step access · CPC title

• H04W74/0838

  using contention-free random access [CFRA] · CPC title

• H04W74/0833 Primary

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

• H04W36/0055

  Transmission or use of information for re-establishing the radio link · CPC title