System and method for retransmission of grant-free traffic

• US 10,187,183 B2
• Filed: 07/29/2016
• Issued: 01/22/2019
• Est. Priority Date: 07/29/2016
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Islam, Toufiqul, Au, Kelvin Kar Kin, Baligh, Mohammadhadi
• Primary Examiner(s): Javaid, Jamal
• Application Number:
  US15/223,690
• Publication Number:
  US 20180035458A1
• Time in Patent Office: 907 Days
• CPC Class Codes: H04L 1/16 in which the return channel carries supervisory signals, e.g. repetition request signals
• CPC Class Codes: H04L 1/1887 Scheduling and prioritising arrangements
• CPC Class Codes: H04L 5/0058 Allocation criteria
• CPC Class Codes: H04L 5/0096 Indication of changes in allocation
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 74/0808 using carrier sensing, e.g. carrier sense multiple access [CSMA]

Abstract

Feedback from a base station is used to reduce retransmissions of a grant-free UE where the SINR of an initial transmission from the grant-free UE is higher than a threshold. Feedback from a base station is also used to adjust transmission by grant-based UEs in resources that overlap with those also available to grant-free UEs.

Claims

1. A method comprising:

during a grant-free transmit time interval (TTI), a base station performing grant-free activity detection;

the base station transmitting a notification to adjust grant-based transmission based on a result of the grant-free activity detection.

2. The method of claim 1 wherein the base station transmitting a notification to adjust grant-based transmission comprises transmitting the notification when activity is detected.

3. The method of claim 1 wherein the notification to adjust grant-free transmission indicates that a grant-based UE configured to make a scheduled transmission using resources that include an area of overlap with resources for grant-free UEs is not to transmit in the area of overlap.

4. The method of claim 1 wherein performing activity detection comprises detecting at least one transmission by at least one grant-free UE with an indication that the at least one transmission will be retransmitted.

5. The method of claim 1 further comprising:

estimating an associated SINR of a detected activity;

wherein the base station transmits the notification to adjust grant-based transmission when activity is detected and the associated SINR is less than a threshold.

6. The method of claim 5 wherein the notification to adjust grant-based transmission indicates that a grant-based UE configured to make a scheduled transmission using resources that include an area of overlap with resources for grant-free UEs is not to transmit in the area of overlap.

7. The method of claim 1 wherein transmitting a notification comprises transmitting an indication of whether or not to adjust grant-based transmission for each of resource area of a plurality of resource areas within a grant-free frequency partition.

8. The method of claim 1 wherein transmitting a notification comprises using a dedicated downlink feedback channel.

9. The method of claim 1 wherein transmitting a notification comprises puncturing downlink transmissions.

10. The method of claim 1 wherein:

performing grant-free activity detection comprises determining whether a detected grant-free transmission is a grant-free transmission in respect of which at least one more retransmission is expected or is a retransmission in respect of which at least one further retransmission is expected; and

the base station transmits the notification to adjust grant-based transmission based on a result of the grant-free activity detection when it is determined that the detected grant-free transmission is a grant-free transmission in respect of which at least one further retransmission is expected, or a retransmission in respect of which at least one further retransmission is expected.

11. The method of claim 1 wherein for the purpose of generating the notification, performing grant-free activity detection comprises performing grant-free activity detection in respect of an uplink resource for an in initial grant-free transmission in respect of which one further retransmission is expected, or in respect of a resource for a retransmission in respect of which at least one further retransmission is expected.

12. A method comprising:

during a grant-free transmit time interval (TTI), a base station performing grant-free activity detection;

estimating an associated signal-to-interference-plus-noise ratio (SINR) of a detected activity;

the base station transmitting a notification to reduce grant-free retransmission based on a result of the grant-free activity detection when activity is detected and the associated SINR is greater than a threshold.

13. The method of claim 12 wherein transmitting a notification comprises using a dedicated downlink feedback channel.

14. The method of claim 12 wherein transmitting a notification comprises puncturing downlink transmissions.

15. The method of claim 12 further comprising:

as part of performing grant-free activity detection, determining whether a detected grant-free transmission is an initial transmission or a retransmission;

the base station transmitting the notification to reduce grant-free retransmission based on a result of the grant-free activity detection when it is determined that the detected grant-free transmission is an initial transmission or a retransmission in respect of which at least one further retransmission is expected.

16. The method of claim 12 wherein for the purpose of generating the notification, performing grant-free activity detection comprises performing grant-free activity detection in respect of uplink resources dedicated to initial grant-free transmissions, or in respect of uplink resources dedicated to retransmissions in respect of which at least one further retransmission is expected.