Random Access Backoff Indicator

Patent metadata

Field	Value
Publication number	US-2020221506-A1
Application number	US-202016738483-A
Country	US
Kind code	A1
Filing date	Jan 9, 2020
Priority date	Jan 9, 2019
Publication date	Jul 9, 2020
Grant date	—

Abstract

A wireless device transmits, for a random access procedure, a first preamble via a cell comprising a first sub-band and a second sub-band. The wireless device receives a random access response. The random access response indicates a first backoff indicator indicating a first backoff time interval of the first sub-band. The random access response indicates a second backoff indicator indicating a second backoff time interval of the second sub-band. The wireless device determines a preamble retransmission for the random access procedure. The wireless device selects, as a backoff time interval, a shorter one of the first backoff time interval and the second backoff time interval. The wireless device performs, at a time based on the backoff time interval, a listen-before-talk procedure.

First claim

What is claimed is:

1 . A method comprising:
transmitting, by a wireless device and for a random access procedure, a first preamble via a cell comprising a first sub-band and a second sub-band; receiving a random access response indicating:
a first backoff indicator indicating a first backoff time interval of the first sub-band; and
a second backoff indicator indicating a second backoff time interval of the second sub-band;
determining a preamble retransmission for the random access procedure; selecting, as a backoff time interval, a shorter one of the first backoff time interval and the second backoff time interval; and performing, at a time based on the backoff time interval, a listen-before-talk procedure.

2 . The method of claim 1 , wherein the listen-before-talk procedure is performed on the first sub-band in response to the first backoff time interval being shorter than the second backoff time interval.

3 . The method of claim 2 , further comprising transmitting a second preamble via the first sub-band based on the listen-before-talk procedure indicating that the first sub-band is clear.

4 . The method of claim 2 , further comprising performing, at a second time based on the second backoff time interval, a second listen-before-talk procedure on the second sub-band based on the listen-before-talk procedure indicating that the first-sub-band is occupied.

5 . The method of claim 4 , further comprising transmitting a third preamble via the second sub-band in response to the second listen-before-talk procedure indicating the second sub-band clear.

6 . The method of claim 5 , wherein there is no random access channel occasion on the first-sub-band between the first time and the second time.

7 . The method of claim 5 , wherein there is at least one random access channel occasion on the first-sub-band between the first time and the second time.

8 . The method of claim 7 , further comprising performing, for the at least one random access channel occasion, at least one third listen-before-talk procedure on the first sub-band, wherein the at least one third listen-before-talk procedure indicates the first-sub-band is occupied.

9 . The method of claim 1 , further comprising transmitting a fourth preamble via the first sub-band in response to the fourth listen-before-talk procedure indicating the first sub-band clear, the fourth listen-before-talk procedure performed on the first sub-band after the listen-before-talk procedure indicating the first-sub-band occupied.

10 . The method of claim 9 , wherein there is no random access channel occasion on the second sub-band between the first time and the third time.

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:
transmit, for a random access procedure, a first preamble via a cell comprising a first sub-band and a second sub-band; receive a random access response indicating:
a first backoff indicator indicating a first backoff time interval of the first sub-band; and
a second backoff indicator indicating a second backoff time interval of the second sub-band;
determine a preamble retransmission for the random access procedure; select, as a backoff time interval, a shorter one of the first backoff time interval and the second backoff time interval; and perform, at a time based on the backoff time interval, a listen-before-talk procedure.

12 . The wireless device of claim 11 , wherein the listen-before-talk procedure is performed on the first sub-band in response to the first backoff time interval being shorter than the second backoff time interval.

13 . The wireless device of claim 12 , wherein the instructions further cause the wireless device to transmit a second preamble via the first sub-band based on the listen-before-talk procedure indicating that the first sub-band is clear.

14 . The wireless device of claim 12 , wherein the instructions further cause the wireless device to perform, at a second time based on the second backoff time interval, a second listen-before-talk procedure on the second sub-band based on the listen-before-talk procedure indicating that the first-sub-band is occupied.

15 . The wireless device of claim 14 , wherein the instructions further cause the wireless device to transmit a third preamble via the second sub-band in response to the second listen-before-talk procedure indicating the second sub-band clear.

16 . The wireless device of claim 15 , wherein there is no random access channel occasion on the first-sub-band between the first time and the second time.

17 . The wireless device of claim 15 , wherein there is at least one random access channel occasion on the first-sub-band between the first time and the second time.

18 . The wireless device of claim 17 , wherein the instructions further cause the wireless device to perform, for the at least one random access channel occasion, at least one third listen-before-talk procedure on the first sub-band, wherein the at least one third listen-before-talk procedure indicates the first-sub-band is occupied.

19 . The wireless device of claim 11 , wherein the instructions further cause the wireless device to transmit a fourth preamble via the first sub-band in response to the fourth listen-before-talk procedure indicating the first sub-band clear, the fourth listen-before-talk procedure performed on the first sub-band after the listen-before-talk procedure indicating the first-sub-band occupied.

20 . A base station and a wireless device, wherein:
the base station comprises one or more processors of the base station and memory storing instructions of the base station that, when executed by the one or more processors of the base station, cause the base station to:
receive, for a random access procedure, a first preamble via a cell comprising a first sub-band and a second sub-band;
transmit a random access response indicating:
a first backoff indicator indicating a first backoff time interval of the first sub-band; and
a second backoff indicator indicating a second backoff time interval of the second sub-band; and
the wireless device comprises one or more processors of the wireless device and memory storing instructions of the wireless device that, when executed by the one or more processors of the wireless device, cause the wireless device to:
transmit the first preamble;
receive the random access response;
determine a preamble retransmission for the random access procedure;
select, as a backoff time interval, a shorter one of the first backoff time interval and the second backoff time interval; and
perform, at a time based on the backoff time interval, a listen-before-talk procedure.

Assignees

• Jeon Hyoungsuk
• Dinan Esmael
• Park Kyungmin
• Cirik Ali
• Zhou Hua
• Babaei Alireza
• Xu Kai

Inventors

• Jeon Hyoungsuk
• Dinan Esmael
• Park Kyungmin
• Cirik Ali
• Zhou Hua
• Babaei Alireza
• Xu Kai

Classifications

• H04W74/0808 Primary

  using carrier sensing, e.g. carrier sense multiple access [CSMA] · 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