Handover method and device in mobile communication system

Patent metadata

Field	Value
Publication number	US-11968573-B2
Application number	US-201917250640-A
Country	US
Kind code	B2
Filing date	Aug 13, 2019
Priority date	Aug 13, 2018
Publication date	Apr 23, 2024
Grant date	Apr 23, 2024

Abstract

A handover method, performed by a source base station in a wireless communication system, includes: receiving an indicator indicating a start of packet duplication transmission of a user plane function (UPF); and transmitting at least one redundant packet to a target base station, based on the indicator indicating the start of the packet duplication transmission of the UPF, wherein the packet duplication transmission includes transmitting, to the target base station, a packet that is identical to a packet transmitted by the UPF to the source base station, wherein the redundant packet includes a packet that was received from the UPF before the start of the packet duplication transmission but is not transmitted to a User Equipment (UE) and stored.

First claim

The invention claimed is:

1. A handover method performed by a source base station in a wireless communication system, the handover method comprising:
receiving, from an access and mobility management function (AMF), a general packet radio service (GPRS) tunneling protocol user plane (GTP-U) sequence number indicating a start of packet duplication transmission of a user plane function (UPF);
receiving, from the UPF, at least one packet being transmitted duplicately and assigned the GTP-U sequence number;
distinguishing the received at least one packet and at least one redundant packet based on the GTP-U sequence number;
transmitting, to a target base station, the at least one redundant packet; and
transmitting, to the target base station, an end-mark indicating that transmission of the redundant packet is completed after transmitting all of the at least one redundant packet to the target base station, or along with a last redundant packet;
wherein the packet duplication transmission includes transmitting, to the target base station, a packet that is identical to a packet transmitted by the UPF;
wherein the at least one redundant packet is received from the UPF before the start of the packet duplication transmission but is not transmitted to a User Equipment (UE) and stored.

2. The handover method of claim 1 , further comprising:
copying the at least one packet received from the UPF; and
transmitting, to the target base station, the copied at least one packet.

3. The handover method of claim 1 , wherein the transmitting, to the target base station, the at least one redundant packet comprises:
transmitting the at least one redundant packet to the target base station via the UPF.

4. The handover method of claim 1 , wherein the transmitting, to the target base station, the at least one redundant packet comprises:
transmitting the at least one redundant packet directly to the target base station.

5. A handover method performed by a target base station in a wireless communication system, the handover method comprising:
receiving, from a user plane function (UPF), at least one packet being transmitted duplicately and assigned a general packet radio service (GPRS) tunneling protocol user plane (GTP-U) sequence number indicating a start of packet duplication transmission of the UPF;
receiving, from a source base station, at least one redundant packet based on the GTP-U sequence number; and
receiving, from the source base station, an end-mark indicating that transmission of the redundant packet is completed after transmitting all of the at least one redundant packet to the target base station, or along with a last redundant packet;
wherein the packet duplication transmission includes transmitting, to the target base station, a packet that is identical to a packet transmitted by the UPF to the source base station;
wherein the at least one redundant packet is received from the UPF before the start of the packet duplication transmission but is not transmitted to a User Equipment (UE) and stored;
wherein the at least one packet and the at least one redundant packet are distinguished based on the GTP-U sequence number.

6. The handover method of claim 5 , further comprising:
receiving, from the source base station, at least one copy of the at least one packet.

7. The handover method of claim 5 , further comprising:
reordering the received at least one packet being transmitted duplicately and the received at least one redundant packet, based on the GTP-U sequence number.

8. The handover method of claim 7 , further comprising:
transmitting, to the UE, the reordered at least one packet.

9. A source base station performing a handover in a wireless communication system, the source base station comprising:
a transceiver;
at least one memory storing programs and data for executing the handover; and
at least one processor configured to, by executing the programs stored in the memory,
receive, from an access and mobility management function (AMF), a general packet radio service (GPRS) tunneling protocol user plane (GTP-U) sequence number indicating a start of packet duplication transmission of a user plane function (UPF),
receive, from the UPF, at least one packet being transmitted duplicately and assigned the GTP-U sequence number,
distinguish the received at least one packet and at least one redundant packet based on the GTP-U sequence number,
transmit, to a target base station, the at least one redundant packet, and
transmit, to the target base station, an end-mark indicating that transmission of the redundant packet is completed after transmitting all of the at least one redundant packet to the target base station, or along with a last redundant packet,
wherein the packet duplication transmission includes transmitting, to the target base station, a packet that is identical to a packet transmitted by the UPF,
wherein the at least one redundant packet is received from the UPF before the start of the packet duplication transmission but is not transmitted to a User Equipment (UE) and stored.

10. The source base station of claim 9 , wherein the at least one processor is further configured to:
copy the at least one packet received from the UPF; and
transmit, to the target base station, the copied at least one packet.

11. The source base station of claim 9 , wherein the at least one processor is further configured to:
transmit the at least redundant packet to the target base station via the UPF.

12. The source base station of claim 9 , wherein the at least one processor is further configured to:
transmit the at least one redundant packet directly to the target base station.

Assignees

• Samsung Electronics Co Ltd
• Univ Korea Res & Bus Found

Inventors

• Kweon Kisuk
• Ko Haneul
• Pack Sangheon
• Lee Jaewook
• Kim Joonwoo
• Tae Yujin

Classifications

• H04W36/026 Primary

  Multicasting of data during hand-off · CPC title

• H04L1/08

  by repeating transmission, e.g. Verdan system {(H04L1/1858 and H04L1/189 take precedence)} · CPC title

• H04W36/08

  Reselecting an access point · CPC title

• H04W36/00837 Primary

  Determination of triggering parameters for hand-off · CPC title

• H04W36/02 Primary

  Buffering or recovering information during reselection {; Modification of the traffic flow during hand-off} · CPC title