Enhanced machine type communications quick idle transition after connection release

Patent metadata

Field	Value
Publication number	US-11219086-B2
Application number	US-201816495059-A
Country	US
Kind code	B2
Filing date	Mar 23, 2018
Priority date	Apr 26, 2017
Publication date	Jan 4, 2022
Grant date	Jan 4, 2022

Abstract

Aspects of the present disclosure provide techniques to enable enhanced machine type communication (s) (eMTC) and/or narrowband Internet-of-Things (NB-IoT) devices to transition to idle mode after releasing a connection, such as a radio resource control (RRC) connection, more quickly than with previously known techniques. An example method includes determining, based on an indication received in a narrowband signal on a narrowband region of a bandwidth comprising a plurality of narrowband regions, whether to wait for a delay period, determined based on a configuration received from a network entity, before releasing a radio resource control (RRC) connection and releasing the RRC connection at a time in accordance with the determination.

First claim

The invention claimed is:

1. A method for wireless communications by a user equipment (UE), comprising:
determining, based on an indication received in a narrowband signal on a narrowband region of a bandwidth comprising a plurality of narrowband regions, whether to wait for a delay period, determined based on a configuration received from a network entity, before releasing a radio resource control (RRC) connection; and
releasing the RRC connection at a time in accordance with the determination;
wherein:
the narrowband signal comprises a command to release the RRC connection;
the indication comprises a set polling bit in a radio link control (RLC) layer portion of the narrowband signal;
the determination is to wait for the delay period, based on the polling bit; and
the method further comprises:
sending a hybrid automatic retransmission request (HARQ) acknowledgment (ACK) of the narrowband signal prior to releasing the RRC connection;
receiving a first downlink control information (DCI) comprising an N 0 grant having a new data indicator (NDI) that is not toggled; and
sending a layer 2 (L2) ACK of the narrowband signal, via transmission resources indicated in the N 0 grant, prior to releasing the RRC connection.

2. The method of claim 1 , wherein the indication is a first indication, the method further comprising:
receiving a second indication comprising an unset polling bit in the RLC layer portion of the narrowband signal; and
determining to not wait for the delay period.

3. The method of claim 2 , further comprising:
powering down one or more radio components of the UE subsequent to releasing the RRC connection.

4. The method of claim 1 , further comprising:
receiving a second DCI comprising a request for a retransmission of the L2 ACK; and
retransmitting the L2 ACK prior to releasing the RRC connection.

5. The method of claim 1 , further comprising:
determining, based on a coverage level of the UE, a length of the delay period.

6. The method of claim 5 , wherein the determining the length of the delay period comprises:
determining a length of a narrowband physical downlink control channel (NPDCCH) period based on a number of repetitions determined based on the coverage level;
determining a number of the NPDCCH periods based on the coverage level; and
calculating the delay period as the determined number of the NPDCCH periods.

7. The method of claim 6 , wherein determining the number of the NPDCCH periods comprises selecting the number from a table of coverage levels, based on the coverage level.

8. The method of claim 1 , further comprising:
receiving a second DCI comprising another NO grant having an NDI that is toggled; and
making a new determination, to not wait for the delay period before releasing the RRC connection, in response to receiving the second DCI.

9. An apparatus for wireless communications, comprising:
a processor configured to:
determine, based on an indication received in a narrowband signal on a narrowband region of a bandwidth comprising a plurality of narrowband regions, whether to wait for a delay period, determined based on a configuration received from a network entity, before causing the apparatus to release a radio resource control (RRC) connection; and
cause the apparatus to release the RRC connection at a time in accordance with the determination; and

a memory coupled with the processor
wherein:
the narrowband signal comprises a command to release the RRC connection;
the indication comprises a set polling bit in a radio link control (RLC) layer portion of the narrowband signal; and
the processor is further configured to:
determine to wait for the delay period, based on the polling bit;
cause the apparatus to send a hybrid automatic retransmission request (HARQ) acknowledgment (ACK) of the narrowband signal prior to releasing the RRC connection;
cause the apparatus to receive a first downlink control information (DCI) comprising an NO grant having a new data indicator (NDI) that is not toggled; and
cause the apparatus to send a layer 2 (L2) ACK of the narrowband signal, via transmission resources indicated in the NO grant, prior to releasing the RRC connection.

10. The apparatus of claim 9 , wherein the indication is a first indication, and the processor is configured to:
receive a second indication comprising an unset polling bit in the RLC layer portion of the narrowband signal;
determine to not wait for the delay period.

11. The apparatus of claim 10 , wherein the processor is configured to:
cause the apparatus to power down one or more radio components of the apparatus subsequent to releasing the RRC connection.

12. The apparatus of claim 9 , wherein the processor is further configured to:
cause the apparatus to receive a second DCI comprising a request for a retransmission of the L2 ACK; and
cause the apparatus to retransmit the L2 ACK prior to releasing the RRC connection.

13. The apparatus of claim 9 , wherein the processor is further configured to:
determine, based on a coverage level of the UE, a length of the delay period.

14. The apparatus of claim 13 , wherein the determining the length of the delay period comprises:
determining a length of a narrowband physical downlink control channel (NPDCCH) period based on a number of repetitions determined based on the coverage level;
determining a number of the NPDCCH periods based on the coverage level; and
calculating the delay period as the determined number of the NPDCCH periods.

15. The apparatus of claim 13 , wherein the processor is further configured to:
cause the apparatus to receive a second DCI comprising another NO grant having an NDI that is toggled; and
make a new determination, to not wait for the delay period before releasing the RRC connection, in response to receiving the second DCI.

16. The apparatus of claim 14 , wherein the processor is configured to determine the number of the NPDCCH periods by selecting the number from a table of coverage levels, based on the coverage level.

17. An apparatus for wireless communications, comprising:
means for determining, based on an indication received in a narrowband signal on a narrowband region of a bandwidth comprising a plurality of narrowband regions, whether to wait for a delay period, determined based on a configuration received from a network entity, before releasing a radio resource control (RRC) connection; and
means for releasing the RRC connection at a time in accordance with the determination;
wherein:
the narrowband signal comprises a command to release the RRC connection;
the indication comprises a set polling bit in a radio link control (RLC) layer portion of the narrowband signal;
the determination is to wait for the delay period, based on the polling bit; and
the apparatus further comprises:
means for sending a hybrid automatic retransmission request (HARQ) acknowledgment (ACK) of the narrowband signal prior to releasing the RRC connection;
means for receiving a first downlink control information (DCI) comprising an NO grant having a new data indicator (NDI) that is not toggled; and
means for sending a layer 2 (L2) ACK of the narrowband signal, via transmission resources indicated in the NO grant, prior to releasing the RRC connection.

18. A computer-readable medium for wireless communications including instructions, the instructions, when executed by a processor, cause the processor to perform operations comprising:
determining, based on an indication received in a narrowband signal on a narrowband

Assignees

• Qualcomm Inc

Inventors

• Iyer Ashish Shankar
• Handa Omesh Kumar
• Hsu Chun-Hao
• Pant Nitin
• Rajagopalan Srinivasan
• Hsu Liangchi
• Liu Feilu
• Dhanapal Muthukumaran
• Rico Alvarino Alberto
• Dang Zhibin

Classifications

• H04W72/23

  in the downlink direction of a wireless link, i.e. towards a terminal · CPC title

• H04W76/30

  Connection release · CPC title

• H04W76/27 Primary

  Transitions between radio resource control [RRC] states · CPC title

• H04L1/1812

  Hybrid protocols; Hybrid automatic repeat request [HARQ] · CPC title

• H04W76/34 Primary

  Selective release of ongoing connections · CPC title