Methods providing transmission of UL data to a source access node after establishing connection with a target access node and related wireless devices

Patent metadata

Field	Value
Publication number	US-12137379-B2
Application number	US-202017628805-A
Country	US
Kind code	B2
Filing date	Aug 13, 2020
Priority date	Aug 15, 2019
Publication date	Nov 5, 2024
Grant date	Nov 5, 2024

Abstract

A method of operating a wireless device ( 300 ) is described. The method includes providing ( 1001 ) a connection with a source access node. The method also includes receiving ( 1005 ) a handover command from the source access node while providing the connection with the source access node. The method also includes establishing ( 1009 ) a connection with a target access node responsive to receiving the handover command. The method further includes transmitting ( 1019 ) uplink data to the source access node after establishing the connection with the target access node. Related wireless devices are also discussed.

First claim

The invention claimed is:

1. A method of operating a wireless device, the method comprising:
receiving a handover command from a source access node while providing a connection with the source access node, the connection with the source access node being provided using a source Radio Link Control (RLC) entity;
establishing a connection with a target access node responsive to receiving the handover command, the connection with the target access node being established using a target RLC entity; and
transmitting uplink data to the source access node after establishing the connection with the target access node, the uplink data including uplink data stored in a transmission buffer of the source RLC entity.

2. The method of claim 1 , wherein:
a Packet Data Convergence Protocol (PDCP) entity is provided for the source and target access nodes; and
the uplink data stored in the transmission buffer of the source RLC entity comprises PDCP data received by the source RLC entity from the PDCP entity before establishing the connection with the target access node.

3. The method of claim 2 , further comprising:
receiving new uplink data at the target RLC entity from the PDCP entity after establishing the connection with the target access node; and
transmitting the new uplink data from the target RLC entity to the target access node after establishing the connection.

4. The method of claim 3 , further comprising retransmitting unacknowledged uplink data from the source RLC entity to the target access node after establishing the connection with the target access node.

5. The method of claim 1 , wherein:
establishing the connection with the target access node comprises:
transmitting a random access preamble to the target access node;
receiving a random access response from the target access node, and transmitting a handover complete message to the target access node; and

the uplink data is transmitted to the source access node after at least one of the following:
receiving the random access response, and transmitting the handover complete message.

6. The method of claim 1 , wherein the handover command includes one or more of the following:
an indication that the handover is an enhanced make-before-break handover; and an identifier for the target access node.

7. The method of claim 1 , wherein the connection is established with the target access node while transmitting uplink data to the source access node.

8. The method of claim 1 , wherein the uplink data transmitted to the source access node after establishing the connection with the target access node comprises a Packet Data Convergence Protocol (PDCP) Control Packet Data Unit (PDU).

9. A wireless device comprising:
processing circuitry; and
a memory operably coupled with the processing circuitry and including instructions that, when executed by the processing circuitry, cause the wireless device to:
receive a handover command from a source access node while providing a connection with the source access node, the connection with the source access node being provided using a source Radio Link Control (RLC) entity;
establish a connection with a target access node responsive to receiving the handover command, the connection with the target access node being established using a target RLC entity; and
transmit uplink data to the source access node after establishing the connection with the target access node, the uplink data including uplink data stored in a transmission buffer of the source RLC entity.

10. The wireless device of claim 9 , wherein:
a Packet Data Convergence Protocol (PDCP) entity is provided for the source and target access nodes; and
the uplink data stored in the transmission buffer of the source RLC entity comprises
PDCP data received by the source RLC entity from the PDCP entity before establishing the connection with the target access node.

11. The wireless device of claim 10 , wherein the memory also includes instructions that, when executed by the processing circuitry, cause the wireless device to:
receive new uplink data at the target RLC entity from the PDCP entity after establishing the connection with the target access node; and
transmit the new uplink data from the target RLC entity to the target access node after establishing the connection.

12. The wireless device of claim 11 , the memory also includes instructions that, when executed by the processing circuitry, cause the wireless device to retransmit unacknowledged uplink data from the source RLC entity to the target access node after establishing the connection with the target access node.

13. The wireless device of claim 9 , wherein:
the executed instructions cause the wireless device to establish the connection with the target access node by:
transmitting a random access preamble to the target access node;
receiving a random access response from the target access node, and transmitting a handover complete message to the target access node; and

the executed instructions cause the wireless device to transmit the uplink data to the source access node after at least one of the following:
receiving the random access response, and transmitting the handover complete message.

14. The wireless device of claim 9 , wherein the handover command includes one or more of the following:
an indication that the handover is an enhanced make-before-break handover; and an identifier for the target access node.

15. The wireless device of claim 9 , wherein the connection is established with the target access node while transmitting uplink data to the source access node.

16. The wireless device of claim 9 , wherein the uplink data transmitted to the source access node after establishing the connection with the target access node comprises a Packet Data Convergence Protocol (PDCP) Control Packet Data Unit (PDU).

17. A non-transitory storage medium including executable program code that, when executed by processing circuitry of a wireless device, causes the wireless device to perform operations corresponding to the method of claim 1 .

Assignees

• Ericsson Telefon Ab L M

Inventors

• Ohlsson Oscar
• Wallentin Pontus
• Rune Johan
• Muller Julien
• Vesely Alexander

Classifications

• H04W36/18

  for allowing seamless reselection, e.g. soft reselection · CPC title

• H04W36/023

  Buffering or recovering information during reselection · CPC title

• H04W36/0235

  by transmitting sequence numbers, e.g. SN status transfer · CPC title

• H04W36/00695 Primary

  using split of the control plane or user plane · CPC title

• H04W36/0016 Primary

  Hand-off preparation specially adapted for end-to-end data sessions · CPC title