Mobility between Cells in a Wireless Network

Patent metadata

Field	Value
Publication number	US-2022141730-A1
Application number	US-202017431203-A
Country	US
Kind code	A1
Filing date	Feb 5, 2020
Priority date	Feb 20, 2019
Publication date	May 5, 2022
Grant date	—

Abstract

One aspect of the disclosure provides a method performed by a wireless device for performing handover from a source network node to a target network node. The method comprises: obtaining (1402) an indication of a round-trip time for transmissions to the target network node; initiating (1406) access to the target network node; and, subsequent to initiating access to the target network node, transmitting (1408) data to or receiving (1408) data from the source network node for a time window following initiation of access to the target network node. The time window has a duration of at least the round-trip time for transmissions to the target network node.

First claim

1 .- 34 . (canceled)

35 . A method performed by a wireless device for performing handover from a source network node to a target network node, the method comprising:
obtaining an indication of a round-trip time for transmissions to the target network node; initiating access to the target network node; and subsequent to initiating access to the target network node, transmitting data to or receiving data from the source network node for a time window following initiation of access to the target network node, wherein the time window has a duration of at least the round-trip time for transmissions to the target network node.

36 . The method of claim 35 , wherein the time window has a duration of at least two round-trip times for transmission to the target network node.

37 . The method of claim 35 , wherein the indication of the round-trip time comprises an indication of a propagation delay for transmissions to or from the target network node.

38 . The method of claim 35 , wherein obtaining the indication of the round-trip time comprises one or more of:
receiving the indication of the round-trip time in a system information broadcast from the target network node; and receiving the indication of the round-trip time in a handover command or trigger from the source network node.

39 . The method of claim 35 , further comprising transmitting a first information message to the source network node, the first information message comprising an indication of a time at which access to the target network node was initiated.

40 . The method of claim 35 , further comprising transmitting a second information message to the source network node, the second information message comprising an indication of a time at which a Message 3 of a random access process was transmitted to the target network node.

41 . A wireless device, the wireless device comprising:
power supply circuitry configured to supply power to the wireless device; and processing circuitry configured to, when performing handover of the wireless device from a source network node to a target network node:
obtain an indication of a round-trip time for transmissions to the target network node;
initiate access to the target network node; and
subsequent to initiating access to the target network node, transmit data to or receive data from the source network node for a time window following initiation of access to the target network node, wherein the time window has a duration of at least the round-trip time for transmissions to the target network node.

42 . The wireless device of claim 41 , wherein the time window has a duration of at least two round-trip times for transmission to the target network node.

43 . The wireless device of claim 41 , wherein the indication of the round-trip time comprises an indication of a propagation delay for transmissions to or from the target network node.

44 . The wireless device of claim 41 , wherein the processing circuitry is further configured to obtain the indication of the round-trip time by one or more of:
receiving the indication of the round-trip time in a system information broadcast from the target network node; and receiving the indication of the round-trip time in a handover command or trigger from the source network node.

45 . The wireless device of claim 41 , wherein the processing circuitry is further configured to cause transmission of a first information message to the source network node, the first information message comprising an indication of a time at which access to the target network node was initiated.

46 . The wireless device of claim 41 , wherein the processing circuitry is further configured to cause transmission of a second information message to the source network node, the second information message comprising an indication of a time at which a Message 3 of a random access process was transmitted to the target network node.

47 . A network node, the network node comprising:
processing circuitry configured to, when performing handover of a wireless device from the network node, acting as a source network node, to a target network node:
obtain an indication of a round-trip time for transmissions from the wireless device to the target network node; and
subsequent to the wireless device initiating access to the target network node, transmit data to or receive data from the wireless device for a time window following the initiation of access to the target network node, wherein the time window has a duration of at least the round-trip time for transmissions from the wireless device to the target network node.

48 . The network node of claim 47 , wherein the time window has a duration of at least two round-trip times for transmission from the wireless device to the target network node.

49 . The network node of claim 47 , wherein the processing circuitry is further configured to obtain the indication of the round-trip time by receiving the indication of the round-trip time from the target network node.

50 . The network node of claim 47 , wherein the processing circuitry is further configured to receive a first information message from the wireless device or the target network node, the first information message comprising an indication of a time at which access to the target network node was initiated.

51 . The network node of claim 47 , wherein the processing circuitry is configured to receive a second information message from the wireless device or the target network node, the second information message comprising an indication of a time at which a Message 3 of a random access process was transmitted to the target network node or received by the target network node.

52 . A network node, the network node comprising:
power supply circuitry configured to supply power to the network node; and processing circuitry configured to, when performing handover of a wireless device to the network node, acting as a target network node, from a source network node:
cause transmission, to the source network node, of an indication of a time window following initiation of access to the network node by the wireless device, in which the source network node is to transmit data to or receive data from the wireless device.

53 . The network node of claim 52 , wherein the time window has a duration of at least a round-trip time for transmissions from the wireless device to the network node.

54 . The network node of claim 52 , wherein the time window has a duration of at least two round-trip times for transmission from the wireless device to the network node.

Assignees

• Ericsson Telefon Ab L M

Inventors

• Määttänen Helka-Liina
• Bergqvist Jens
• Hofström Björn

Classifications

• H04W36/328

  by altitude · CPC title

• H04W36/18

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

• H04W36/0072 Primary

  of resource information of target access point · CPC title

• H04W56/0065

  using measurement of signal travel time · CPC title

• H04B7/18502

  Airborne stations · CPC title