Apparatus, method, and computer program

Abstract

The disclosure relates to an apparatus comprising means for suspending (700) a network connection via a first base station onboard a first vehicle, determining (702) that device context stored on the first base station onboard the first vehicle is expected to be available to a second base station onboard a second vehicle, and attempting (704) to resume the network connection via the second base station onboard the second vehicle.

Description

Technical Field

[0001] The present disclosure relates to an apparatus, a method, and a computer program for attempting to resume network connection via a base station mounted on a vehicle. (vehicle)

Background Art

[0002] A communication system can be regarded as a facility that enables a communication session between two or more entities, such as a communication device, a base station, and / or other nodes, by providing a carrier between various entities involved in a communication path.

[0003] The communication system may be a wireless communication system. Examples of wireless systems include public land mobile networks (PLMNs) that operate based on wireless standards provided by 3GPP, satellite-based communication systems, and different wireless local networks, such as those provided by wireless local area networks (WLAN). A wireless system can typically be divided into cells and is thus often referred to as a cellular system.

[0004] Communication systems and related devices typically operate according to a given standard or specification that presents the operations permitted to various entities related to the system and how to implement them. The communication protocols and / or parameters used for the connection are also typically defined. An example of a standard is the so-called 5G standard.

Summary of the Invention

[0005] ​In one embodiment, the present invention provides an apparatus that includes means for interrupting a network connection via a first base station mounted on a first vehicle, determining that an apparatus context stored on the first base station mounted on the first vehicle is expected to be available to a second base station mounted on a second vehicle, and attempting to resume a network connection via a second base station mounted on a second vehicle.

[0006] The second base station mounted on the second vehicle may or may not be connected to the network. Different scenarios are possible when attempting to re-establish network connectivity via the second base station mounted on the second vehicle.

[0007] In this scenario, the second base station may be connected to the network and may not have previously received and stored the device context from the first base station. The second base station may now receive and store the device context from the first base station. Therefore, the device context may be available to the second base station. Re-establishing network connectivity via the second base station may be successful.

[0008] In another scenario, the second base station may be connected to the network and may have previously received and stored the device context from the first base station. Therefore, the device context may be available to the second base station. Re-establishing network connectivity via the second base station may be successful.

[0009] In another scenario, the second base station may not be connected to the network, but may have been connected to the network previously. The second base station may have previously received and remembered the device context. Therefore, the device context may be available to the second base station. Re-establishing network connectivity via the second base station may be successful.

[0010] In another scenario, the second base station may not be connected to the network, nor may it have been connected to the network previously. The second base station may not have previously received and stored the device context. Therefore, the device context may not be available to the second base station. Re-establishing network connectivity via the second base station may not be successful.

[0011] The device may include means for receiving a network connection release message from a first base station mounted on a first vehicle, and attempting to resume network connectivity via a second base station mounted on a second vehicle may include sending a network connection resume message to the second base station mounted on the second vehicle.

[0012] A network connection release message may include an identifier associated with the device context, and a network connection resumption message may include an identifier associated with the device context.

[0013] The device may include means for receiving a network connection resume complete message from a second base station mounted on a second vehicle.

[0014] The device may include means for detecting a failure to receive a network connection resumption completion message from a second base station mounted on a second vehicle, and for storing an identifier associated with the device context on the device.

[0015] The device may include means for later retransmitting a network connectivity resumption message, which includes an identifier associated with the device context, to a second base station mounted on a second vehicle.

[0016] The identifier may be stored along with at least one of the following parameters: a time parameter indicating how long the identifier is stored on the device before it is removed from the device; a maximum number of attempts parameter indicating the maximum number of times the device will later retransmit to a second base station mounted on a second vehicle; a network connection reactivation message containing the identifier before it is removed from the device; or a maximum number of identifiers parameter indicating the maximum number of identifiers the device will store.

[0017] The device may include means for sending a network connection setup message, which does not include an identifier associated with the device context, to a second base station mounted on a second vehicle.

[0018] The device may include means for detecting the failure to receive a network connection setup complete message from the second base station mounted on the second vehicle when the second base station mounted on the second vehicle is not connected to the network.

[0019] The device may include means for detecting a failure to receive a network connection setup complete message from a second base station mounted on a second vehicle, determining that a device context stored on a first base station mounted on a first vehicle is expected to be available to a third base station mounted on a third vehicle, and sending a network connection resume message to the third base station mounted on the third vehicle, which includes an identifier associated with the device context.

[0020] The device may include means for detecting failure to receive a network connection setup complete message from a second base station mounted on a second vehicle, determining that a third base station mounted on a third vehicle is expected to be connected to the network, and sending a network connection setup message to the third base station mounted on the third vehicle that does not include an identifier associated with the device context.

[0021] Determining that a device context stored on a first base station mounted on a first vehicle is expected to be available to a second base station mounted on a second vehicle may include determining that the device context transfer time has expired since the time the connection to the network was interrupted.

[0022] The device context transfer time may be received by the device from the first base station mounted on the first satellite, or it may be calculated by the device.

[0023] Determining whether the device context stored on the first base station mounted on the first vehicle is expected to be available to the second base station mounted on the second vehicle is an indicator from the first base station mounted on the first vehicle to the second base station mounted on the second vehicle. (Information to show, indication) This may include receiving an index of a cell serviced by a second base station mounted on a second vehicle.

[0024] The indicator may show that the device context stored on the first base station mounted on the first vehicle is expected to be available to the second base station mounted on the second vehicle.

[0025] The network connection release message may include at least one of the following: device context transfer time, an indicator of a second base station mounted on a second vehicle, or an indicator of a cell served by a second base station mounted on a second vehicle.

[0026] Determining that the device context stored on the first base station mounted on the first vehicle is expected to be available to the second base station mounted on the second vehicle may include receiving a paging message from the second base station mounted on the second vehicle.

[0027] The paging message may include at least one of an indicator indicating that the device context is available to the second base station mounted on the second vehicle, or an indicator indicating that the second base station mounted on the second vehicle expects to resume a network connection via the second base station mounted on the second vehicle.

[0028] The device is moving outside the coverage of the first base station mounted on the first vehicle, or The device coverage outside to The first base station mounted on the first vehicle will Determining that it is moving, and means for transmitting an indicator indicating that the device is moving outside the coverage of the first base station mounted on the first vehicle, or The device coverage outside to The first base station mounted on the first vehicle will a first base station mounted on the first vehicle or a second base station mounted on the second vehicle indicating that it is moving.

[0029] The device is moving within the coverage of the second base station mounted on the second vehicle, or The device coverage Inside to The second base station, mounted on the second vehicle, may include means for determining that it is moving.

[0030] The device may include means for determining that the device has high priority data and for attempting to set up a network connection via the second base station mounted on the second vehicle without first attempting to resume the network connection via the second base station mounted on the second vehicle.

[0031] The device may be user equipment.

[0032] The first vehicle, the second vehicle, and / or the third vehicle may be a satellite, a drone, or a car.

[0033] The first vehicle, the second vehicle, and / or the third vehicle may be stations that have intermittent connectivity to the network.

[0034] In one embodiment, the provided device comprises at least one processor and at least one memory containing computer code for one or more programs, wherein the at least one memory and the computer code are configured to cause the device to, using at least one processor, to interrupt a network connection via a first base station mounted on a first vehicle, determine that a device context stored on the first base station mounted on the first vehicle is expected to be available to a second base station mounted on a second vehicle, and attempt to resume a network connection via a second base station mounted on a second vehicle.

[0035] The second base station mounted on the second vehicle may or may not be connected to the network. Different scenarios are possible when attempting to re-establish network connectivity via the second base station mounted on the second vehicle.

[0036] In this scenario, the second base station may be connected to the network and may not have previously received and stored the device context from the first base station. The second base station may now receive and store the device context from the first base station. Therefore, the device context may be available to the second base station. The second base station may successfully re-establish network connectivity.

[0037] In another scenario, the second base station may be connected to the network and may have previously received and stored the device context from the first base station. Therefore, the device context may be available to the second base station. Re-establishing network connectivity via the second base station may be successful.

[0038] In another scenario, the second base station may not be connected to the network, but may have been connected to the network previously. The second base station may have previously received and remembered the device context. Therefore, the device context may be available to the second base station. Re-establishing network connectivity via the second base station may be successful.

[0039] In another scenario, the second base station may not be connected to the network, nor may it have been connected to the network previously. The second base station may not have previously received and stored the device context. Therefore, the device context may not be available to the second base station. Re-establishing network connectivity via the second base station may not be successful.

[0040] At least one memory and computer code may be configured, using at least one processor, to cause the device to receive at least one network connection release message from a first base station mounted on a first vehicle, and attempting to resume network connectivity via a second base station mounted on a second vehicle may include sending a network connection resume message to the second base station mounted on the second vehicle.

[0041] A network connection release message may include an identifier associated with the device context, and a network connection resumption message may include an identifier associated with the device context.

[0042] At least one memory and computer code may be configured, using at least one processor, to cause the device to receive at least one network connection resumption complete message from a second base station mounted on a second vehicle.

[0043] At least one memory and computer code may be configured to cause the device to detect at least a failure to receive a network connection resumption complete message from a second base station mounted on a second vehicle, and to store an identifier associated with the device context on the device, using at least one processor.

[0044] At least one memory and computer code may be configured, using at least one processor, to cause the device to later retransmit a network connectivity resumption message, which includes an identifier associated with the device context, to at least a second base station mounted on a second vehicle.

[0045] The identifier may be stored along with at least one of the following parameters: a time parameter indicating how long the identifier is stored on the device before it is removed from the device; a maximum number of attempts parameter indicating the maximum number of times the device will later retransmit to a second base station mounted on a second vehicle; a network connection reactivation message containing the identifier before it is removed from the device; or a maximum number of identifiers parameter indicating the maximum number of identifiers the device will store.

[0046] At least one memory and computer code may be configured, using at least one processor, to cause the device to send at least one network connection setup message to a second base station mounted on a second vehicle, which does not include an identifier associated with the device context.

[0047] At least one memory and computer code may be configured, using at least one processor, to cause the device to detect at least a failure to receive a network connection setup complete message from the second base station mounted on the second vehicle when the second base station mounted on the second vehicle is not connected to the network.

[0048] At least one memory and computer code may be configured, using at least one processor, to cause the device to at least detect a failure to receive a network connection setup complete message from a second base station mounted on a second vehicle, determine that the device context stored on a first base station mounted on a first vehicle is expected to be available to a third base station mounted on a third vehicle, and send a network connection resume message to the third base station mounted on the third vehicle, which includes an identifier associated with the device context.

[0049] At least one memory and computer code may be configured, using at least one processor, to cause the device to at least detect failure to receive a network connection setup complete message from a second base station mounted on a second vehicle, determine that a third base station mounted on a third vehicle is expected to be connected to the network, and send a network connection setup message to the third base station mounted on the third vehicle that does not include an identifier associated with the device context.

[0050] Determining that a device context stored on a first base station mounted on a first vehicle is expected to be available to a second base station mounted on a second vehicle may include determining that the device context transfer time has expired since the time the connection to the network was interrupted.

[0051] The device context transfer time may be received by the device from the first base station mounted on the first satellite, or it may be calculated by the device.

[0052] Determining that a device context stored on a first base station mounted on a first vehicle is expected to be available to a second base station mounted on a second vehicle may include receiving an index of the second base station mounted on the second vehicle, or an index of a cell served by the second base station mounted on the second vehicle, from the first base station mounted on the first vehicle.

[0053] The indicator may show that the device context stored on the first base station mounted on the first vehicle is expected to be available to the second base station mounted on the second vehicle.

[0054] The network connection release message may include at least one of the following: device context transfer time, an indicator of a second base station mounted on a second vehicle, or an indicator of a cell served by a second base station mounted on a second vehicle.

[0055] Determining that a device context stored on a first base station mounted on a first vehicle is expected to be available to a second base station mounted on a second vehicle may include receiving a paging message from the second base station mounted on the second vehicle.

[0056] The paging message may include at least one of the following: an indicator that the device context is available to the second base station mounted on the second vehicle, or an indicator that the second base station mounted on the second vehicle expects the device to resume network connectivity via the second base station mounted on the second vehicle.

[0057] At least one memory and computer code, using at least one processor, enables the device to determine at least that the device is moving outside the coverage of the first base station mounted on the first vehicle, or The device coverage outside to The first base station mounted on the first vehicle will Determining that it is moving, and determining that the device has moved outside the coverage of the first base station mounted on the first vehicle, or the second base station mounted on the second vehicle, The device coverage outside to The first base station mounted on the first vehicle will It may be configured to transmit an indicator that it is moving.

[0058] At least one memory and computer code, using at least one processor, enables the device to move within the coverage of a second base station mounted on a second vehicle, or The device coverage Inside to The second base station, mounted on the second vehicle, It can be configured to determine if it is moving.

[0059] At least one memory and computer code may be configured to cause the device to, using at least one processor, determine that the device has high-priority data, and to attempt to set up a network connection via the second base station mounted on the second vehicle without first attempting to resume the network connection via the second base station mounted on the second vehicle.

[0060] The device may be user equipment.

[0061] The first vehicle, the second vehicle, and / or the third vehicle may be a satellite, a drone, or a car.

[0062] The first vehicle, the second vehicle, and / or the third vehicle may be stations that have intermittent connectivity to the network.

[0063] In one embodiment, the provided device includes a circuit configured to interrupt a network connection via a first base station mounted on a first vehicle, determine that a device context stored on the first base station mounted on the first vehicle is expected to be available to a second base station mounted on a second vehicle, and attempt to resume the network connection via a second base station mounted on a second vehicle.

[0064] The second base station mounted on the second vehicle may or may not be connected to the network. Different scenarios are possible when attempting to re-establish network connectivity via the second base station mounted on the second vehicle.

[0065] In this scenario, the second base station may be connected to the network and may not have previously received and stored the device context from the first base station. The second base station may now receive and store the device context from the first base station. Therefore, the device context may be available to the second base station. Re-establishing network connectivity via the second base station may be successful.

[0066] In another scenario, the second base station may be connected to the network and may have previously received and stored the device context from the first base station. Therefore, the device context may be available to the second base station. Re-establishing network connectivity via the second base station may be successful.

[0067] In another scenario, the second base station may not be connected to the network, but may have been connected to the network previously. The second base station may have previously received and remembered the device context. Therefore, the device context may be available to the second base station. Re-establishing network connectivity via the second base station may be successful.

[0068] In another scenario, the second base station may not be connected to the network, nor may it have been connected to the network previously. The second base station may not have previously received and stored the device context. Therefore, the device context may not be available to the second base station. Re-establishing network connectivity via the second base station may not be successful.

[0069] The device may include a circuit configured to receive a network connection release message from a first base station mounted on a first vehicle, and attempting to resume network connectivity via a second base station mounted on a second vehicle may include sending a network connection resume message to the second base station mounted on the second vehicle.

[0070] A network connection release message may include an identifier associated with the device context, and a network connection resume message may include an identifier associated with the device context.

[0071] The device may include circuitry configured to receive a network connection resumption completion message from a second base station mounted on a second vehicle.

[0072] The device may include circuitry configured to detect failure to receive a network connection resumption complete message from a second base station mounted on a second vehicle, and to store an identifier associated with the device context on the device.

[0073] The device may include circuitry configured to later retransmit a network connectivity resumption message, which includes an identifier associated with the device context, to a second base station mounted on a second vehicle.

[0074] The identifier may be stored along with at least one of the following parameters: a time parameter indicating how long the identifier is stored on the device before it is removed from the device; a maximum number of attempts parameter indicating the maximum number of times the device will later retransmit the identifier to a second base station mounted on a second vehicle; a network connection reactivation message containing the identifier before it is removed from the device; or a maximum number of identifiers parameter indicating the maximum number of identifiers the device will store.

[0075] The device may include circuitry configured to send a network connection setup message, which does not include an identifier associated with the device context, to a second base station mounted on a second vehicle.

[0076] The device may include circuitry configured to detect a failure to receive a network connection setup complete message from the second base station mounted on the second vehicle when the second base station mounted on the second vehicle is not connected to the network.

[0077] The device may include circuitry configured to detect failure to receive a network connection setup complete message from a second base station mounted on a second vehicle, determine that a device context stored on a first base station mounted on a first vehicle is expected to be available to a third base station mounted on a third vehicle, and send a network connection resume message to the third base station mounted on the third vehicle, which includes an identifier associated with the device context.

[0078] The device may include circuitry configured to detect failure to receive a network connection setup complete message from a second base station mounted on a second vehicle, determine that a third base station mounted on a third vehicle is expected to be connected to the network, and send a network connection setup message to the third base station mounted on the third vehicle that does not include an identifier associated with the device context.

[0079] Determining that a device context stored on a first base station mounted on a first vehicle is expected to be available to a second base station mounted on a second vehicle may include determining that the device context transfer time has expired since the time the connection to the network was interrupted.

[0080] The device context transfer time may be received by the device from the first base station mounted on the first satellite, or it may be calculated by the device.

[0081] Determining that a device context stored on a first base station mounted on a first vehicle is expected to be available to a second base station mounted on a second vehicle may include receiving an index of the second base station mounted on the second vehicle, or an index of a cell served by the second base station mounted on the second vehicle, from the first base station mounted on the first vehicle.

[0082] The indicator may show that the device context stored on the first base station mounted on the first vehicle is expected to be available to the second base station mounted on the second vehicle.

[0083] The network connection release message may include at least one of the following: device context transfer time, an indicator of a second base station mounted on a second vehicle, or an indicator of a cell served by a second base station mounted on a second vehicle.

[0084] Determining that a device context stored on a first base station mounted on a first vehicle is expected to be available to a second base station mounted on a second vehicle may include receiving a paging message from the second base station mounted on the second vehicle.

[0085] The paging message may include at least one of the following: an indicator that the device context is available to the second base station mounted on the second vehicle, or an indicator that the second base station mounted on the second vehicle expects the device to resume network connectivity via the second base station mounted on the second vehicle.

[0086] The device is moving outside the coverage of the first base station mounted on the first vehicle, or The device coverage outside to The first base station mounted on the first vehicle will It is determined that the device is moving, and the first base station mounted on the first vehicle, or the second base station mounted on the second vehicle, is notified that the device has moved outside the coverage of the first base station mounted on the first vehicle, or The device coverage outside to The first base station mounted on the first vehicle will It may include circuitry configured to transmit an indicator that it is moving.

[0087] The device is moving within the coverage of a second base station mounted on a second vehicle, or The device coverage Inside to The second base station, mounted on the second vehicle, It may include a circuit configured to determine whether something is moving.

[0088] The device may include a circuit configured to determine that the device has high-priority data and to attempt to set up a network connection via the second base station mounted on the second vehicle without first attempting to resume network connectivity via the second base station mounted on the second vehicle.

[0089] The device may be user equipment.

[0090] The first vehicle, the second vehicle, and / or the third vehicle may be a satellite, a drone, or a car.

[0091] The first vehicle, the second vehicle, and / or the third vehicle may be stations that have intermittent connectivity to the network.

[0092] In one embodiment, a method is provided which includes interrupting a network connection via a first base station mounted on a first vehicle, determining that a device context stored on the first base station mounted on the first vehicle is expected to be available to a second base station mounted on a second vehicle, and attempting to resume a network connection via a second base station mounted on a second vehicle.

[0093] The method may be carried out by an apparatus.

[0094] The second base station mounted on the second vehicle may or may not be connected to the network. Different scenarios are possible when attempting to re-establish network connectivity via the second base station mounted on the second vehicle.

[0095] In this scenario, the second base station may be connected to the network and may not have previously received and stored the device context from the first base station. The second base station may now receive and store the device context from the first base station. Therefore, the device context may be available to the second base station. Re-establishing network connectivity via the second base station may be successful.

[0096] In another scenario, the second base station may be connected to the network and may have previously received and stored the device context from the first base station. Therefore, the device context may be available to the second base station. Re-establishing network connectivity via the second base station may be successful.

[0097] In another scenario, the second base station may not be connected to the network, but may have been connected to the network previously. The second base station may have previously received and remembered the device context. Therefore, the device context may be available to the second base station. Re-establishing network connectivity via the second base station may be successful.

[0098] In another scenario, the second base station may not be connected to the network, nor may it have been connected to the network previously. The second base station may not have previously received and stored the device context. Therefore, the device context may not be available to the second base station. Re-establishing network connectivity via the second base station may not be successful.

[0099] The method may include receiving a network connection release message from a first base station mounted on a first vehicle, and attempting to resume network connectivity via a second base station mounted on a second vehicle may include sending a network connection resume message to the second base station mounted on the second vehicle.

[0100] A network connection release message may include an identifier associated with the device context, and a network connection resumption message may include an identifier associated with the device context.

[0101] The method may include receiving a network connection reconnection completion message from a second base station mounted on a second vehicle.

[0102] The method may include detecting failure to receive a network connection resumption completion message from a second base station mounted on a second vehicle, and storing an identifier associated with the device context on the device.

[0103] The method may include later resending a network connectivity resumption message, which includes an identifier associated with the device context, to a second base station mounted on a second vehicle.

[0104] The identifier may be stored along with at least one of the following parameters: a time parameter indicating how long the identifier is stored on the device before it is removed from the device; a maximum number of attempts parameter indicating the maximum number of times the device will later retransmit to a second base station mounted on a second vehicle; a network connection reactivation message containing the identifier before it is removed from the device; or a maximum number of identifiers parameter indicating the maximum number of identifiers the device will store.

[0105] The method may include sending a network connection setup message to a second base station mounted on a second vehicle, which does not include an identifier associated with the device context.

[0106] The method may include detecting a failure to receive a network connection setup complete message from the second base station mounted on the second vehicle when the second base station mounted on the second vehicle is not connected to the network.

[0107] The method may include detecting a failure to receive a network connection setup complete message from a second base station mounted on a second vehicle, determining that the device context stored on a first base station mounted on a first vehicle is expected to be available to a third base station mounted on a third vehicle, and sending a network connection resume message to the third base station mounted on the third vehicle, which includes an identifier associated with the device context.

[0108] The method may include detecting a failure to receive a network connection setup complete message from a second base station mounted on a second vehicle, determining that a third base station mounted on a third vehicle is expected to be connected to the network, and sending a network connection setup message to the third base station mounted on the third vehicle that does not include an identifier associated with the device context.

[0109] Determining that a device context stored on a first base station mounted on a first vehicle is expected to be available to a second base station mounted on a second vehicle may include determining that the device context transfer time has expired since the time the connection to the network was interrupted.

[0110] The device context transfer time may be received by the device from the first base station mounted on the first satellite, or it may be calculated by the device.

[0111] Determining that a device context stored on a first base station mounted on a first vehicle is expected to be available to a second base station mounted on a second vehicle may include receiving an index of the second base station mounted on the second vehicle, or an index of a cell served by the second base station mounted on the second vehicle, from the first base station mounted on the first vehicle.

[0112] The indicator may show that the device context stored on the first base station mounted on the first vehicle is expected to be available to the second base station mounted on the second vehicle.

[0113] The network connection release message may include at least one of the following: device context transfer time, an indicator of a second base station mounted on a second vehicle, or an indicator of a cell served by a second base station mounted on a second vehicle.

[0114] Determining that a device context stored on a first base station mounted on a first vehicle is expected to be available to a second base station mounted on a second vehicle may include receiving a paging message from the second base station mounted on the second vehicle.

[0115] The paging message may include at least one of the following: an indicator that the device context is available to the second base station mounted on the second vehicle, or an indicator that the second base station mounted on the second vehicle expects the device to resume network connectivity via the second base station mounted on the second vehicle.

[0116] The method involves the device moving outside the coverage of the first base station mounted on the first vehicle, or The device coverage outside to The first base station mounted on the first vehicle will Determining that it is moving, and determining that the device has moved outside the coverage of the first base station mounted on the first vehicle, or the second base station mounted on the second vehicle, The device coverage outside to The first base station mounted on the first vehicle will This may include transmitting an indicator that it is moving.

[0117] The method involves the device moving into the coverage of a second base station mounted on a second vehicle, or The device coverage Inside to The second base station, mounted on the second vehicle, This may include determining whether something is moving.

[0118] The method may include determining that the device has high-priority data and attempting to set up a network connection by a second base station mounted on a second vehicle, without prior attempting to resume network connectivity by a second base station mounted on a second vehicle.

[0119] The device may be user equipment.

[0120] The first vehicle, the second vehicle, and / or the third vehicle may be a satellite, a drone, or a car.

[0121] The first vehicle, the second vehicle, and / or the third vehicle may be stations that have intermittent connectivity to the network.

[0122] In one embodiment, a computer program is provided which includes computer executable code configured to, when executed on at least one processor, interrupt a network connection via a first base station mounted on a first vehicle, determine that a device context stored on the first base station mounted on the first vehicle is expected to be available to a second base station mounted on a second vehicle, and attempt to resume a network connection via a second base station mounted on a second vehicle.

[0123] At least one processor may be part of the device.

[0124] The second base station mounted on the second vehicle may or may not be connected to the network. Different scenarios are possible when attempting to re-establish network connectivity via the second base station mounted on the second vehicle.

[0125] In this scenario, the second base station may be connected to the network and may not have previously received and stored the device context from the first base station. The second base station may now receive and store the device context from the first base station. Therefore, the device context may be available to the second base station. Re-establishing network connectivity via the second base station may be successful.

[0126] In another scenario, the second base station may be connected to the network and may have previously received and stored the device context from the first base station. Therefore, the device context may be available to the second base station. Re-establishing network connectivity via the second base station may be successful.

[0127] In another scenario, the second base station may not be connected to the network, but may have been connected to the network previously. The second base station may have previously received and remembered the device context. Therefore, the device context may be available to the second base station. Re-establishing network connectivity via the second base station may be successful.

[0128] In another scenario, the second base station may not be connected to the network, nor may it have been connected to the network previously. The second base station may not have previously received and stored the device context. Therefore, the device context may not be available to the second base station. Re-establishing network connectivity via the second base station may not be successful.

[0129] The computer program may include computer executable code configured to receive a network connection release message from a first base station mounted on a first vehicle when running on at least one processor, and attempting to resume network connectivity via a second base station mounted on a second vehicle may include sending a network connection resume message to the second base station mounted on the second vehicle.

[0130] A network connection release message may include an identifier associated with the device context, and a network connection resumption message may include an identifier associated with the device context.

[0131] The computer program may include computer executable code configured to receive a network connection resumption completion message from a second base station mounted on a second vehicle, when executed on at least one processor.

[0132] The computer program may include computer executable code configured to, when executed on at least one processor, detect failure to receive a network connection resumption complete message from a second base station mounted on a second vehicle, and store an identifier associated with the device context on the device.

[0133] The computer program may include computer executable code that, when executed on at least one processor, is configured to later resend a network connectivity resumption message, which includes an identifier associated with the device context, to a second base station mounted on a second vehicle.

[0134] The identifier may be stored along with at least one of the following parameters: a time parameter indicating how long the identifier is stored on the device before it is removed from the device; a maximum number of attempts parameter indicating the maximum number of times the device will later retransmit to a second base station mounted on a second vehicle; a network connection reactivation message containing the identifier before it is removed from the device; or a maximum number of identifiers parameter indicating the maximum number of identifiers the device will store.

[0135] The computer program may include computer executable code configured to run on at least one processor to send a network connection setup message, which does not include an identifier associated with the device context, to a second base station mounted on a second vehicle.

[0136] The computer program may include computer executable code configured to detect, when running on at least one processor, a failure to receive a network connection setup complete message from a second base station mounted on a second vehicle when the second base station mounted on the second vehicle is not connected to the network.

[0137] The computer program may include computer executable code configured to, when executed on at least one processor, detect a failure to receive a network connection setup complete message from a second base station mounted on a second vehicle, determine that a device context stored on a first base station mounted on a first vehicle is expected to be available to a third base station mounted on a third vehicle, and send a network connection resume message to the third base station mounted on the third vehicle, which includes an identifier associated with the device context.

[0138] The computer program may include computer executable code configured to, when run on at least one processor, detect a failure to receive a network connection setup complete message from a second base station mounted on a second vehicle, determine that a third base station mounted on a third vehicle is expected to be connected to the network, and send a network connection setup message to the third base station mounted on the third vehicle that does not include an identifier associated with the device context.

[0139] Determining that a device context stored on a first base station mounted on a first vehicle is expected to be available to a second base station mounted on a second vehicle may include determining that the device context transfer time has expired since the time the connection to the network was interrupted.

[0140] The device context transfer time may be received by the device from the first base station mounted on the first satellite, or it may be calculated by the device.

[0141] Determining that a device context stored on a first base station mounted on a first vehicle is expected to be available to a second base station mounted on a second vehicle may include receiving an index of the second base station mounted on the second vehicle, or an index of a cell served by the second base station mounted on the second vehicle, from the first base station mounted on the first vehicle.

[0142] The indicator may show that the device context stored on the first base station mounted on the first vehicle is expected to be available to the second base station mounted on the second vehicle.

[0143] The network connection release message may include at least one of the following: device context transfer time, an indicator of a second base station mounted on a second vehicle, or an indicator of a cell served by a second base station mounted on a second vehicle.

[0144] Determining that a device context stored on a first base station mounted on a first vehicle is expected to be available to a second base station mounted on a second vehicle may include receiving a paging message from the second base station mounted on the second vehicle.

[0145] The paging message may include at least one of the following: an indicator that the device context is available to the second base station mounted on the second vehicle, or an indicator that the second base station mounted on the second vehicle expects the device to resume network connectivity via the second base station mounted on the second vehicle.

[0146] The computer program, when running on at least one processor, indicates that the device has moved outside the coverage of the first base station mounted on the first vehicle, or The devicecoverage outside to The first base station mounted on the first vehicle will It is determined that the device is moving, and the first base station mounted on the first vehicle, or the second base station mounted on the second vehicle, is notified that the device has moved outside the coverage of the first base station mounted on the first vehicle, or The device coverage outside to The first base station mounted on the first vehicle will This may include computer executable code configured to send indicators that it is moving.

[0147] The computer program, when running on at least one processor, indicates that the device is moving within the coverage of a second base station mounted on a second vehicle, or The device coverage Inside to The second base station, mounted on the second vehicle, It may include computer executable code configured to determine whether something is moving.

[0148] The computer program may include computer executable code configured to, when executed on at least one processor, determine that a device has high-priority data and attempt to set up a network connection via the second base station mounted on the second vehicle, without prior attempting to resume network connectivity via the second base station mounted on the second vehicle.

[0149] The device may be user equipment.

[0150] The first vehicle, the second vehicle, and / or the third vehicle may be a satellite, a drone, or a car.

[0151] The first vehicle, the second vehicle, and / or the third vehicle may be stations that have intermittent connectivity to the network.

[0152] In one embodiment, a computer-readable medium is provided which includes program instructions stored thereon for performing at least one of the above methods.

[0153] In one embodiment, a non-temporary computer-readable medium is provided, which includes program instructions stored thereon for performing at least one of the above methods.

[0154] According to one embodiment, a non-volatile tangible memory medium is provided, which includes program instructions stored thereon for performing at least one of the above methods.

[0155] Many different embodiments have been described above. It should be understood that further embodiments may be provided by any combination of two or more of the embodiments described above.

[0156] Various other embodiments are also described in the following detailed description and the attached claims.

[0157] List of abbreviations AF: Application Function AMF: Access and Mobility Management Function API: Application Programming Interface AS: Access Layer BS: Base station CU: Centralized Unit CP: Control Plane DL: Downlink DU: Distributed Unit EPS: Evolutionary Packet System eMTC: Extended Machine Type Communication eNB: eNodeB or eNodeB or E-UTRANNodeB gNB; gnodeB GSM: Pan-European Digital Mobile Telephone System GW: Gateway HSS: Home Subscriber Server ID: Identifier IoT: Internet of Things LTE: Long-Term Evolution MAC: Media Access Control MS: Mobile station MTC: Machine Type Communication NAS: Non-accessible layer NEF: Network Exposure Function NF: Network Function NR: New Radio NRF: Network Repository Function NTN: Non-terrestrial network PDU: Packet Data Unit RAM: Random Access Memory (R)AN: (Wireless) Access Network ROM: Read-only memory RRC: Wireless Resource Control S&F: Store and Forward SMF: Session Management Function TAU: Tracking Area Update TN: Terrestrial network TR: Technical Report TS: Technical Specifications UE: User Equipment UMTS: Universal Mobile Telecommunications System UP: User Plane WI:Work item 3GPP: Third Generation Partnership Project 5G: Fifth Generation 5GC: 5G Core Network 5GS: 5G system

[0158] Embodiments are described here with reference to the accompanying drawings, merely as examples. [Brief explanation of the drawing]

[0159] [Figure 1] This shows a schematic representation of the 5G system. [Figure 2] A schematic representation of the control device is shown. [Figure 3] This shows a general representation of the user's equipment. [Figure 4]This shows the signaling diagram for the radio resource control connection reactivation procedure in an evolved packet system according to TS36.330 (Figure 7.3a.3-3: RRC connection reactivation procedure in eNBs with different EPS). [Figure 5] This deployment shows that the first e-node B on the first satellite is connected to the network, the second e-node B on the second satellite is not connected to the network, and the third e-node B on the third satellite is connected to the network. [Figure 6] This is a flowchart illustrating a method for attempting to re-establish network connectivity via a base station mounted on a vehicle. [Figure 7] This shows a block diagram of a method for attempting to reactivate network connectivity via a base station mounted on a vehicle. [Figure 8] This diagram shows a schematic representation of a non-volatile memory medium that stores instructions that, when executed by a processor, enable the processor to perform one or more of the steps in the method shown in Figure 7. [Modes for carrying out the invention]

[0160] The following describes an embodiment relating to a mobile communication device that enables communication over a wireless cellular system, and a mobile communication system that serves such a mobile communication device. Before describing the exemplary embodiment in detail, some general principles of wireless communication systems, their access systems, and mobile communication devices are briefly explained with reference to Figures 1, 2, and 3 to help understand the underlying technology of the embodiment described.

[0161] Figure 1 shows a schematic representation of a 5G system (5GS). 5GS may include user equipment (UE), a (radio) access network ((R)AN), a 5G core network (5GC), one or more application functions (AF), and one or more data networks (DN).

[0162] 5G(R)AN may include a terrestrial network (TN) portion, in which one or more gNBs are located on one or more masts or towers on the ground. 5G(R)AN may also include a non-terrestrial network (NTN) portion, in which one or more gNBs are located on one or more satellites or on one or more masts or towers on the ground.

[0163] One or more gNBs may include one or more distributed gNB unit functions connected to one or more centralized gNB unit functions.

[0164] 5GC may include access and mobility management functions (AMF), session management functions (SMF), authentication server functions (AUSF), user data management (UDM), user plane functions (UPF), and / or network exposure functions (NEF). 5GC may include gateways (GWs) to the NTN portion of 5G(R)AN.

[0165] Figure 2 shows an example of a control unit 200 that controls a function of (R)AN or 5GC as shown in Figure 1. The control unit may include at least one random access memory (RAM) 211a, at least one read-only memory (ROM) 211b, at least one processor 212, 213, and an input / output interface 214. At least one processor 212, 213 may be coupled to RAM 211a and ROM 211b. At least one processor 212, 213 may be configured to execute appropriate software code 215. The software code 215 may, for example, execute one or more steps to execute one or more of these embodiments. The software code 215 may be stored in ROM 211b. The control unit 200 may be interconnected with another control unit 200 that controls another function of 5G (R)AN or 5GC. In some embodiments, each function of (R)AN or 5GC includes the control unit 200. In alternative embodiments, two or more functions of (R)AN or 5GC may share the control unit.

[0166] Figure 3 shows an example of a user device 300, such as the user device (UE) shown in Figure 1. The UE 300 may be provided by any device capable of transmitting and receiving wireless signals. Non-limiting examples include a user device, a mobile station (MS) or mobile device such as a mobile phone or what is called a “smartphone”, a computer equipped with a wireless interface card or other wireless interface equipment (e.g., a USB dongle), a personal digital assistant (PDA) or tablet equipped with wireless communication capabilities, a machine-type communication (MTC) device, a cellular IoT (CIoT), or any combination thereof. The UE 300 may, for example, provide data communication for carrying communications. Communications may be one or more of the following: voice, email, text messages, multimedia, data, machine data, etc.

[0167] The UE300 may receive signals via air or radio interface 307 through equipment suitable for receiving radio signals, and may transmit signals through equipment suitable for transmitting radio signals. Figure 3 schematically shows a transceiver unit by block 306. The transceiver unit 306 may be provided, for example, by a radio component and associated antenna configuration. The antenna configuration may be located inside or outside the mobile device.

[0168] The UE300 may include at least one processor 301, at least one memory ROM 302a, at least one RAM 302b, and other possible components 303 for use in software and hardware-assisted execution of tasks designed to be performed, including control of access to an access system and other communication devices, and communication using the access system and other communication devices. At least one processor 301 is coupled to the RAM 302b and the ROM 302a. At least one processor 301 may be configured to execute appropriate software code 308. The software code 308 may, for example, enable the execution of one or more of these embodiments. The software code 308 may be stored in the ROM 302a.

[0169] The processor, storage, and other related control devices may be provided on a suitable circuit board and / or chipset. This feature is indicated by reference numeral 304. The device may optionally have a user interface such as a keypad 305, a touch-sensitive screen or pad, or a combination thereof. Optionally, one or more of a display, a speaker, and a microphone may be provided depending on the type of device.

[0170] One or more aspects of this disclosure relate to NTN, which is defined for NR and Narrow Band Internet of Things (NB-IoT) and / or Extended Machine Type Communications (eMTC) in Release 17. As part of preparation for Release 18, the company submitted a proposal in December 2021 for a description of work items in RAN#94e.

[0171] In RP-212940, satellite companies submitted a joint proposal including a new scenario: store-and-forward operation for IoT NTN. RP-212940 (Section 4.1.4 Support for Store-and-Forward Operation) is written as follows:

[0172] "Store-and-Forward (S&F) is a new feature that enables satellites to provide services to IoT NTN devices even during periods / regions when the satellite is not connected to a ground gateway. An eNB onboard architecture is envisioned. Non-synchronous operation of service links and feeder links is envisioned. Messages are stored on the board until line of sight with the GW is established. A candidate set of enhancement targets includes the following: • Support for separated signaling procedures between "UE <-> satellite with onboard RAN node" and "satellite with onboard RAN node <-> ground-based CN" to achieve end-to-end functionality [RAN2, RAN3] • Dynamic attachment between S-GW and eNB [RAN3]

[0173] The store-and-forward operation is based on the concept of discontinuous coverage scenarios in Release 17, in which the UE has coverage from the satellite only occasionally and temporarily. The discontinuous coverage scenario can also be extended by defining that the satellite is not always connected to the core network (i.e., the GW).

[0174] The following explanation applies to EPS as an example, but should be understood to be applicable to other systems such as 5GS or its next-generation systems. The explanation relates to eNB as an example, but should be understood to be applicable to other BS such as gNB or its next-generation BS.

[0175] The store-and-forward operation could enable low-cost deployments consisting of just a few satellite-based BSs and a few ground-based BSs. This means that the connectivity cost per UE can be reduced at the cost of enabling latency-tolerant data support.

[0176] The challenge in store-and-forward operation scenarios is how the UE can establish an RRC connection (i.e., a secure connection) with the EPC when the links between the UE and the satellite-based eNB, and between the satellite-based eNB and the EPC, are unavailable at the same time.

[0177] Assuming that the RRC connection with the EPC is established by the UE, it may be beneficial to maintain the UE context in the UE and the eNB onboard the satellite. The UE context may include the Access Layer (AS) and Radio Resource Control (RRC) configurations.

[0178] The UE may receive an RRC connection release message from the eNB onboard the satellite. The RRC connection release message may include an indicator (e.g., cause) that the RRC connection was interrupted. The RRC connection release message may also include a resume ID.

[0179] The restart ID may be associated with the UE context. The restart ID may be stored by the onboard eNB along with the UE context. The restart ID may include a UE ID portion and / or an eNB ID portion. The restart ID may include the inactive radio network primary identifier for 5GS.

[0180] The UE may then decide to resume the RRC connection. For example, the UE may want to resume the RRC connection if it has UE-initiated traffic to send to the EPC. The UE may want to resume the RRC connection after a radio link failure. The UE may want to resume the RRC connection after a handover failure. The UE may want to resume the RRC connection after receiving a paging message from the EPC.

[0181] When a UE wishes to resume RRC connectivity, it may send an RRC connectivity resume message to another eNB on a different satellite. The RRC connectivity resume message may include a resume ID. The resume ID may enable the other eNB on the other satellite to fetch the UE context from the satellite-based eNB via the EPC and store the UE context on the other eNB on the other satellite.

[0182] Figure 4 shows the signaling diagram for the radio resource control connection restart procedure in an evolved packet system according to TS36.330 (Figure 7.3a.3-3: RRC connection restart procedure in eNBs with different EPS). TS36.330 (Section 7.3a.3-3 User Plane CIoT EPS / 5GS Optimization) is written as follows:

[0183] "1. Same as step 1 for resuming the internal (ng-)eNB connection." 2. The new (ng-)eNB uses the restart ID (for EPS) or I-RNTI (for 5GS) to locate the old (ng-)eNB and retrieves the UE context using the X2-AP (for EPS) or Xn-AP (for 5GS) UE context acquisition procedure. 3. The old (ng-)eNB responds with the UE context associated with the restart ID (for EPS) or I-RNTI (for 5GS). 4. Similar to step 2 for resuming the internal (ng-)eNB connection. 5. Similar to step 3 for resuming the internal (ng-)eNB connection. 6. Similar to step 4 for resuming the internal (ng-)eNB connection. 7. In the case of EPS, the new eNB initiates the S1-AP path switch procedure to establish an S1 UE-related signaling connection to the serving MME and requests the MME to restart the UE context. In the case of 5GS, the new ng-eNB initiates the NG-AP path switch procedure to establish an NG UE-related signaling connection to the serving AMF and requests the AMF to restart the UE context. 8. In the case of EPS, the MME requests the S-GW to activate the S1-U bearer for the UE and update the downlink path. In the case of 5GS, the AMF requests the SMF to restart the PDU session, and the SMF requests the UPF to create tunnel information about the UE and update the downlink path. 9. MME / AMF acknowledges step 7. 10. In the case of EPS, after the S1-AP path switch procedure, the new eNB triggers the release of the UE context in the old eNB using the X2-AP UE context release procedure. In the case of 5GS, after the NG-AP path switch procedure, the new ng-eNB triggers the release of the UE context in the old ng-eNB using the Xn-AP UE context release procedure.

[0184] As shown in Figure 4, it is expected that other eNBs on other satellites (i.e., "new eNBs") will obtain the UE context from the satellite-mounted eNB (i.e., "old eNBs") via the EPC. This can be a challenge in store-and-forward operation because the other eNBs on other satellites (i.e., "new eNBs") and the satellite-mounted eNB (i.e., "old eNBs") may not be connected to the EPC simultaneously.

[0185] One or more aspects of this disclosure may provide options for how to configure a UE to attempt to reactivate RRC connectivity via other base stations on other satellites (i.e., “new eNBs”), particularly in store-and-forward operations.

[0186] TS36.331 (Section 5.3.3.2 Start) defines the conditions for resuming the RRC connection, and states the following:

[0187] "The UE initiates a procedure when the upper layer requests the establishment or resumption of an RRC connection while the UE is in the RRC_IDLE state, or when the upper layer requests the resumption of an RRC connection while the UE is in the RRC_INACTIVE state, or when the RRC layer requests the resumption of an RRC connection, for example, to receive RNAU or RAN paging."

[0188] The UE may initiate the RRC connection procedure by sending an RRC connection resumption request message to another eNB onboard another satellite. The RRC connection resumption request message may include information such as the following:

[0189] RRCConnectionResumeRequest message -- ASN1START RRCConnectionResumeRequest-r13 ::= SEQUENCE { criticalExtensions CHOICE { rrcConnectionResumeRequest-r13 RRCConnectionResumeRequest-r13-IEs, rrcConnectionResumeRequest-r15 RRCConnectionResumeRequest-5GC-r15-IEs } } RRCConnectionResumeRequest-r13-IEs ::= SEQUENCE { resumeIdentity-r13 CHOICE { resumeID-r13 ResumeIdentity-r13, truncatedResumeID-r13 BIT STRING (SIZE (24)) }, shortResumeMAC-I-r13 BIT STRING (SIZE (16)), resumeCause-r13 ResumeCause, spare BIT STRING (SIZE (1)) } RRCConnectionResumeRequest-5GC-r15-IEs ::= SEQUENCE { resumeIdentity-r15 CHOICE { fullI-RNTI-r15 I-RNTI-r15, shortI-RNTI-r15 ShortI-RNTI-r15 }, shortResumeMAC-I-r15 BIT STRING (SIZE (16)), resumeCause-r15 ResumeCause-r15, spare BIT STRING (SIZE (1)) } ResumeCause ::= ENUMERATED { emergency, highPriorityAccess, mt-Access, mo-Signalling, mo-Data, delayTolerantAccess-v1020, mo-VoiceCall-v1280, mt-EDT-v1610 } ResumeCause-r15 ::= ENUMERATED { emergency, highPriorityAccess, mt-Access, mo-Signalling, mo-Data, rna-Update, mo-VoiceCall, spare1 } -- ASN1STOP

[0190]

Table 1

[0191] By sending an RRC connection resumption message to another eNB on another satellite (i.e., a "new eNB"), the UE may restore the RRC configuration. The UE may then apply integrity protection and encryption according to the existing security context.

[0192] In this scenario, another eNB onboard another satellite (i.e., a "new eNB") may respond to the RRC reconnection message with a different RRC reconnection message. The UE may update its security key based on the content of the other RRC reconnection message and the UE context. The UE may continue to reconnect the RRC connection via the other eNB onboard another satellite (i.e., a "new eNB").

[0193] In another scenario, another eNB onboard another satellite (i.e., a "new eNB") may respond to an RRC connection restart message using an RRC connection setup message. The UE may discard the UE context (including the security key).

[0194] In another scenario, another eNB on another satellite (i.e., a "new eNB") may respond to an RRC connection resumption message with an RRC connection denial message. The UE may discard the UE context (including the security key). The UE may notify higher layers of the failure to reactivate the RRC connection via the other eNB on the other satellite.

[0195] In another scenario, another eNB on another satellite (i.e., a "new eNB") may respond to an RRC connection resume message with an RRC connection release message. The UE may update its UE context (including security key and C-RNTI). The UE may remain in a suspended RRC state.

[0196] One or more aspects of this disclosure may constitute how and / or when a UE is permitted to attempt to reactivate RRC connectivity via another eNB onboard another satellite (i.e., the “New eNB”) in a store-and-forward operation scenario.

[0197] In this scenario, it can be assumed that the UE context is likely to be available to other eNBs on other satellites (i.e., "new eNBs") before the UE enters the coverage of other eNBs on other satellites (i.e., "new eNBs") and / or while the UE is within the coverage of other eNBs on other satellites (i.e., "new eNBs").

[0198] Figure 5 shows a deployment where the first e-node B on the first satellite SAT1 is connected to the EPC, the second e-node B on the second satellite SAT2 is not connected to the EPC, and the third e-node B on the third satellite SAT3 is connected to the EPC.

[0199] The UE may set up an RRC connection via the first e-node B mounted on the first satellite SAT1. For example, the UE may send an RRC connection setup message to the first e-node B mounted on the first satellite SAT1. The first e-node B mounted on the first satellite SAT1 may store a restart ID associated with the UE context along with the UE context.

[0200] The first e-node B onboard the first satellite SAT1 may instruct the UE to interrupt the RRC connection. For example, the first e-node B onboard the first satellite SAT1 may send an RRC connection release message to the UE.

[0201] The RRC connection release message may include a restart ID associated with the UE context.

[0202] The RRC connection release message may include a UE context transfer time that enables the first e-node B, EPC, or proxy onboard the first satellite SAT1 to transfer the UE context to the third e-node B onboard the third satellite SAT3.

[0203] The RRC connection release message may include an indicator (e.g., SAT ID) of the third e-node B onboard the third satellite SAT3 from the first satellite SAT1, or an indicator (e.g., PCI) of the cell served via the third e-node B onboard the third satellite SAT3.

[0204] The RRC connection release message may include an indicator of an attempt to reactivate the RRC connection via the third e-node B onboard the third satellite, SAT3. The indicator may include the cause set in "resume_store_forward".

[0205] The UE may store the restart ID associated with the UE context. The UE may interrupt the RRC connection via the first e-node B mounted on the first satellite SAT1.

[0206] The UE context does not necessarily have to be available to the second e-node B on the second satellite SAT2, but the UE context may be available to the third e-node B on the third satellite SAT3.

[0207] In this embodiment, the UE does not need to attempt to reactivate the RRC connection via the second e-node B on the second satellite SAT2. The EPC may choose not to transmit data for the UE to the second e-node B on the second satellite SAT2. However, this can make it difficult for the EPC to know that the UE context may not be available to the second e-node B on the second satellite SAT2 when the first e-node B on the first satellite SAT1 is not connected to the EPC and therefore cannot obtain such information from the first e-node B on the first satellite SAT1.

[0208] In another embodiment, the UE context may not be available to the second e-node B on the second satellite SAT2. The UE may attempt to reactivate the RRC connection via the second e-node B on the second satellite SAT2. Attempts to reactivate the RRC connection via the second e-node B on the second satellite SAT2 may fail. The UE may store the reactivation ID associated with the UE context received in the RRC connection release message from the first e-node B on the first satellite SAT1. The UE may use the reactivation ID to later retry reactivating the RRC connection via the second e-node B on the second satellite SAT2, or to attempt to reactivate the RRC connection via the third e-node B on the third satellite SAT3.

[0209] The UE may store the restart ID along with one or more parameters.

[0210] The UE may store the restart ID associated with the UE context, along with a timer parameter indicating how long to use the restart ID to retry restarting the RRC connection via the second e-node B on the second satellite SAT2, or to attempt restarting the RRC connection via the third e-node B on the third satellite SAT3.

[0211] The UE may store the restart ID associated with the UE context, along with a maximum number of attempts parameter indicating the maximum number of times it will attempt to restart the RRC connection via the second e-node B on the second satellite SAT2, or via the third e-node B on the third satellite SAT3, using the restart ID.

[0212] The UE may store the restart IDs associated with the UE context, along with a maximum restart ID parameter that indicates the maximum number of IDs that the UE will store.

[0213] In this way, the UE can control the length and number of restart IDs that can be stored by the UE.

[0214] In another embodiment, the UE context may be available to a third e-node B onboard a third satellite, SAT3. The UE may attempt to reactivate the RRC connection via the third e-node B onboard SAT3. For example, the UE may send an RRC connection reactivation message to the third e-node B onboard SAT3. The RRC connection reactivation message may include a reactivation ID associated with the UE context.

[0215] After receiving the RRC connection release message, the UE may attempt to re-establish the RRC connection via the third e-node B on the third satellite SAT3. As described above, the RRC connection release message may include the expiration of the UE context transfer time, which allows the first e-node B, EPC, or proxy on the first satellite SAT1 to transfer the UE context to the third e-node B on the third satellite SAT3, from the time the RRC connection was interrupted.

[0216] After receiving the RRC connection release message, the UE may attempt to re-establish the RRC connection via the third e-node B on the third satellite SAT3. As described above, the RRC connection release message may include an identifier (e.g., SAT ID) for the third e-node B on the third satellite SAT3 from the first satellite SAT1, or an identifier (e.g., PCI) for the cell served by the third e-node B on the third satellite SAT3.

[0217] After receiving a paging message from the third e-node B onboard the third satellite SAT3, the UE may attempt to re-establish RRC connectivity via the third e-node B onboard the third satellite SAT3. The paging message may be a specialized or dedicated paging message.

[0218] The paging message may include an indicator that the UE can continue transmitting ULs to the EPC via the third e-node B on the third satellite SAT3, or that the third e-node B on the third satellite SAT3 has feedback about the previous UL transmission to the EPC via the first e-node B on the first satellite SAT1.

[0219] This may include cases where the UE transmitted data in a previous UL transmission via the first satellite SAT1, and the application transmitting the data can anticipate feedback to the UE from the EPC or the application on the other side. The third satellite SAT3 may carry this feedback from the EPC to the UE.

[0220] The third e-node B onboard the third satellite SAT3 may carry application layer feedback to some application layer data, which the UE previously sent to the EPC via the first e-node B onboard the first satellite SAT1. The first e-node B onboard the first satellite SAT1 may provide data to the EPC. The EPC may obtain application feedback from an application layer sink (e.g., a database or server). The application layer feedback may be forwarded from the EPC to the third e-node B onboard the third satellite SAT3 so that the third e-node B onboard the third satellite SAT3 can provide the application layer feedback to the UE.

[0221] The paging message may include an indicator that the UE context is available to the third e-node B, which is mounted on the third satellite, SAT3.

[0222] The paging message may include an indicator of an attempt to reactivate the RRC connection via the third e-node B onboard the third satellite SAT3. The indicator may include a flag bit set to "1" or "0" (e.g., a restart flag) for each UE ID in the paging record, indicating an attempt to reactivate the RRC connection by the third e-node B onboard the third satellite SAT3, or to attempt to set up a new RRC connection via the third e-node B onboard the third satellite SAT3. The flag bit may be added to TS36.331 as follows:

[0223] The paging message may include a restart ID delivered to the third satellite SAT3 via the EPC or proxy, which the UE can then match with a restart ID associated with the UE context stored on the UE.

[0224] "Paging ::= SEQUENCE { pagingRecordList PagingRecordList OPTIONAL, -- Need ON systemInfoModification ENUMERATED {true} OPTIONAL, -- Need ON etws-Indication ENUMERATED {true} OPTIONAL, -- Need ON nonCriticalExtension Paging-v890-IEs OPTIONAL } PagingRecordList ::= SEQUENCE (SIZE (1..maxPageRec)) OF PagingRecord PagingRecord ::= SEQUENCE { ue-Identity PagingUE-Identity, cn-Domain ENUMERATED {ps, cs}, ResumeFlag BOOLEAN ... } PagingUE-Identity ::= CHOICE { s-TMSI S-TMSI, imsi IMSI, ..., ng-5G-S-TMSI-r15 NG-5G-S-TMSI-r15, fullI-RNTI-r15 I-RNTI-r15 }"

[0225] Alternatively, the UE context may not be available to the second e-node B on the second satellite SAT2, and the UE context may not be available to the third e-node B on the third satellite SAT3.

[0226] In this embodiment, when the third e-node B on the third satellite SAT3 is connected to the EPC, the UE may set up a new RRC connection with the third e-node B on the third satellite SAT3. For example, the UE may send an RRC connection setup message to the third e-node B on the third satellite SAT3. The RRC connection may be an RRC connection for non-access layer-based recovery. The EPC (i.e., the GW) may clean up the previous UE context stored by the third e-node B on the third satellite SAT3.

[0227] In another embodiment, when the third e-node B on the third satellite SAT3 is not connected to the EPC, the UE may wait for the UE context to become available to the fourth e-node B on the fourth satellite SAT4, and may attempt to reactivate the RRC connection via the fourth e-node B on the fourth satellite SAT4. For example, the UE may send an RRC connection reactivation message to the fourth e-node B on the fourth satellite SAT4.

[0228] In another embodiment, when the third e-node B on the third satellite SAT3 is not connected to the EPC, the UE may wait for the fourth e-node B on the fourth satellite SAT4 to connect to the EPC, and may set up a new RRC connection via the fourth e-node B on the fourth satellite SAT4. The UE may send an RRC connection setup message to the fourth e-node B on the fourth satellite SAT4.

[0229] In another embodiment, when the third e-node B on the third satellite SAT3 is not connected to the EPC, the UE may set up a new RRC connection via the third e-node B on the third satellite SAT3. The UE may send an RRC connection setup message to the third e-node B on the third satellite SAT3. The UE may wait for the third e-node B on the third satellite SAT3 to connect to the EPC and complete the setup of the new RRC connection via the third e-node B on the third satellite SAT3.

[0230] The first e-node B on the first satellite SAT1 may give time (i.e., a delay) to complete the setup of a new RRC connection via the third e-node B on the third satellite SAT3 when the first e-node B on the first satellite SAT1 instructs the UE to suspend the RRC connection. The time (i.e., delay) to complete the setup of a new RRC connection via the third e-node B on the third satellite SAT3 may be given in the RRC connection release message.

[0231] If the UE supports a control plane (CP) solution in which packets can be delivered using the NAS security key, the UE may set up an RRC connection to transmit packets using the NAS security key via a third eNodeB mounted on a third satellite SAT3. In this case, the EPC may ensure that it does not release the security key provided to the (R)AN for the UP solution. In other words, the EPC may ensure the coexistence of UP- and CP-based solutions for this scenario. If the third eNodeB mounted on the third satellite SAT3 is not connected to the EPC, the packets may be buffered by the third satellite SAT3 to enable the EPC (i.e., GW) to subsequently verify the security of the packets. EPS may optionally configure this "switch to the CP solution". The conditions may be based on the priority of the packets and / or the number of packets.

[0232] When the UE moves out of the coverage area of the first eNodeB mounted on the first satellite SAT1, the UE may perform a Tracking Area Update (TAU) to indicate to the first eNodeB mounted on the first satellite SAT1 that the UE is present in a new area. The new area may be a tracking area, the coverage area of the third eNodeB mounted on the third satellite SAT3 indicated in the RRC release message, the coverage area of the cell served by the third eNodeB mounted on the third satellite SAT3 indicated in the RRC release message, etc.

[0233] After performing the TAU, the UE may wait for the UE context to become available in the new area. The UE may know that the context is available based on a paging message. In the case of uplink-directed data, the EPC may respond to the TAU with an "estimated time until context becomes available in the new TAU" parameter, thereby enabling the UE to defer the RRC connection re-establishment procedure accordingly.

[0234] When the UE has high-priority data (e.g., an emergency call or exception data), the UE may attempt to set up a new RRC connection via the third eNodeB mounted on the third satellite SAT3 as soon as possible without attempting to resume the RRC connection via the third eNodeB mounted on the third satellite SAT3.

[0235] One or more aspects of the present disclosure may allow the UE to use RRC connection release (i.e., interruption) procedures and RRC connection resume procedures, thereby significantly reducing the time to complete random access and start data transfer compared to a full RRC connection setup.

[0236] One or more aspects of the present disclosure may enable the UE to determine when / which satellite-mounted eNodeB to use to perform RRC connection release (i.e., interruption) procedures and RRC connection resume procedures (RRC inactive in NR) in a store-and-forward operation scenario. This may be useful for avoiding failed and full RRC connection setup procedures.

[0237] FIG. 6 is a flowchart of a method for attempting to resume a network connection via an eNodeB mounted on a satellite.

[0238] First, the UE may set up an RRC connection via the first eNodeB mounted on the first satellite SAT1. For example, the UE may send an RRC connection setup message to the first eNodeB mounted on the first satellite SAT1. The first eNodeB mounted on the first satellite SAT1 may store a resume ID associated with the UE context along with the UE context.

[0239] The first eNodeB mounted on the first satellite SAT1 may instruct the UE to release the RRC connection. For example, the first eNodeB mounted on the first satellite SAT1 may send an RRC connection release message to the UE.

[0240] The RRC connection release message may include a restart ID associated with the UE context.

[0241] The RRC connection release message may include a UE context transfer time that enables the first e-node B, EPC, or proxy onboard the first satellite SAT1 to transfer the UE context to the third e-node B onboard the third satellite SAT3.

[0242] The RRC connection release message may include an indicator (e.g., SAT ID) of the third e-node B onboard the third satellite SAT3 from the first satellite SAT1, or an indicator (e.g., PCI) of the cell served by the third e-node B onboard the third satellite SAT3.

[0243] The RRC connection release message may include an indicator of an attempt to reactivate the RRC connection via the third e-node B onboard the third satellite, SAT3. The indicator may include the cause set in "resume_store_forward".

[0244] The UE may store the restart ID associated with the UE context. The UE may release (i.e., suspend) the RRC connection via the first e-node B mounted on the first satellite SAT1.

[0245] In step 600, the UE may determine that it has a restart ID associated with a UE context stored on the UE.

[0246] In step 602, the UE may determine that the third e-node B on the third satellite SAT3 (i.e., the new satellite) is available. That is, the UE may determine that the UE is within the coverage of the third e-node B on the third satellite SAT3. The UE may determine whether the UE context is expected to be available on the third e-node B on the third satellite SAT3.

[0247] In step 604 (option A), the UE may determine whether the RRC release message includes UE context transfer time and whether the UE context transfer time has expired.

[0248] If the RRC release message includes the UE context transfer time and the UE context transfer time has expired, the method proceeds to step 606.

[0249] If the RRC release message does not include UE context transfer time, or if the RRC release message includes UE context transfer time but the UE context transfer time has not expired, the method proceeds to step 608.

[0250] In step 610 (option B), the UE may determine whether the RRC release message includes an index (e.g., SAT ID) of the third e-node B mounted on the third satellite SAT3 from the first satellite SAT1, or an index (e.g., PCI) of the cell served by the third e-node B mounted on the third satellite SAT3.

[0251] If the RRC release message includes an index (e.g., SAT ID) of the third e-node B onboard the third satellite SAT3 from the first satellite SAT1, or an index (e.g., PCI) of the cell served by the third e-node B onboard the third satellite SAT3, the method proceeds to step 606.

[0252] If the RRC release message does not include an index (e.g., SAT ID) of the third e-node B onboard the third satellite SAT3 from the first satellite SAT1, or an index (e.g., PCI) of the cell served by the third e-node B onboard the third satellite SAT3, the method proceeds to step 608.

[0253] In step 612 (Option C), the UE may determine whether the UE has received a paging message, and the paging message includes an indicator indicating that the UE context is available at the third eNode B mounted on the third satellite SAT3.

[0254] If the UE determines that it has received a paging message and the paging message includes an indicator indicating that the UE context is available at the third eNode B mounted on the third satellite SAT3, the method proceeds to step 606.

[0255] If the UE may determine that it has not received a paging message, or if the paging message does not include an indicator indicating that the UE context is available at the third eNode B mounted on the third satellite SAT3, the method proceeds to step 608.

[0256] In step 614 (Option D), the UE may determine whether the UE has received a paging message from the third eNode B mounted on the third satellite SAT3.

[0257] If the UE may determine that it has received a paging message from the third eNode B mounted on the third satellite SAT3, the method proceeds to step 606.

[0258] If the UE may determine that it has not received a paging message from the third eNode B mounted on the third satellite SAT3, the method proceeds to step 608.

[0259] In step 606, the UE may attempt to resume the RRC connection via the third eNode B mounted on the third satellite SAT3. For example, the UE may send an RRC connection resume message to the third eNode B mounted on the third satellite SAT3. The RRC connection resume message may include a resume ID.

[0260] In step 616, the UE may determine whether the RRC connection has been reactivated via the third e-node B on the third satellite SAT3. For example, the UE may determine whether it has received an RRC connection reactivation complete message from the third e-node B on the third satellite SAT3.

[0261] If the RRC connection is re-established via the third e-node B on the third satellite SAT3, proceed to method 618.

[0262] If the RRC connection is not re-established via the third e-node B on the third satellite SAT3, proceed to step 620.

[0263] In step 618, the RRC connection is established via the third e-node B on the third satellite, SAT3.

[0264] In step 620, the UE may store the restart ID for later use (for example, it may attempt to restart the RRC connection again via the third e-node B on the third satellite SAT3). The method proceeds to step 608.

[0265] In step 608, the UE may attempt to set up a new RRC connection using the third e-node B on the third satellite SAT3. For example, the UE may send an RRC connection setup message to the third e-node B on the third satellite SAT3. The RRC connection setup message does not include a restart ID.

[0266] Figure 7 shows a block diagram of a method for attempting to re-establish network connectivity via a base station on a satellite. The method can be performed by equipment, such as user equipment.

[0267] In step 700, the device may interrupt the network connection via the first base station mounted on the first vehicle.

[0268] In step 702, the device may determine that the device context stored on the first base station mounted on the first vehicle is expected to be available to the second base station mounted on the second vehicle.

[0269] In step 704, the device may attempt to re-establish network connectivity via a second base station mounted on a second vehicle.

[0270] The second base station mounted on the second vehicle may or may not be connected to the network. Different scenarios are possible when attempting to re-establish network connectivity via the second base station mounted on the second vehicle.

[0271] In this scenario, the second base station may be connected to the network and may not have previously received and stored the device context from the first base station. The second base station may now receive and store the device context from the first base station. Therefore, the device context may be available to the second base station. Re-establishing network connectivity via the second base station may be successful.

[0272] In another scenario, the second base station may be connected to the network and may have previously received and stored the device context from the first base station. Therefore, the device context may be available to the second base station. The second base station may successfully re-establish network connectivity.

[0273] In another scenario, the second base station may not be connected to the network, but may have been connected to the network previously. The second base station may have previously received and remembered the device context. Therefore, the device context may be available to the second base station. Re-establishing network connectivity via the second base station may be successful.

[0274] In another scenario, the second base station may not be connected to the network, nor may it have been connected to the network previously. The second base station may not have previously received and stored the device context. Therefore, the device context may not be available to the second base station. Re-establishing network connectivity via the second base station may not be successful.

[0275] The device may receive a network connection release message from a first base station mounted on a first vehicle. Attempting to resume network connectivity via a second base station mounted on a second vehicle may include sending a network connection resume message to the second base station mounted on the second vehicle.

[0276] Network connection release messages may include identifiers associated with the device context. Network connection resumption messages may include identifiers associated with the device context.

[0277] The device may receive a network connection resumption completion message from a second base station mounted on a second vehicle.

[0278] The device may detect a failure to receive a network connection resumption completion message from a second base station mounted on a second vehicle. The device may store an identifier associated with the device context on the device.

[0279] The device may later resend a network connectivity resumption message, including an identifier associated with the device context, to a second base station mounted on a second vehicle.

[0280] The identifier may be stored along with at least one of the following parameters: a time parameter indicating how long the identifier is stored on the device before it is removed from the device; a maximum number of attempts parameter indicating the maximum number of times the device will later retransmit to a second base station mounted on a second vehicle; a network connection reactivation message containing the identifier before it is removed from the device; or a maximum number of identifiers parameter indicating the maximum number of identifiers the device will store.

[0281] The device may send a network connection setup message to a second base station mounted on a second vehicle, which does not include an identifier associated with the device context.

[0282] The device may detect a failure to receive a network connection setup completion message from the second base station mounted on the second vehicle when the second base station mounted on the second vehicle is not connected to the network.

[0283] The device may detect a failure to receive a network connection setup complete message from the second base station mounted on the second vehicle. The device may determine that the device context stored on the first base station mounted on the first vehicle is expected to be available to the third base station mounted on the third vehicle. The device may send a network connection resume message to the third base station mounted on the third vehicle, which includes an identifier associated with the device context.

[0284] The device may detect a failure to receive a network connection setup complete message from the second base station mounted on the second vehicle. The device may determine that the third base station mounted on the third vehicle is expected to be connected to the network. The device may send a network connection setup message to the third base station mounted on the third vehicle that does not include an identifier associated with the device context.

[0285] Determining that a device context stored on a first base station mounted on a first vehicle is expected to be available to a second base station mounted on a second vehicle may include determining that the device context transfer time has expired since the time the connection to the network was interrupted.

[0286] The device context transfer time may be received by the device from the first base station mounted on the first satellite, or it may be calculated by the device.

[0287] Determining that a device context stored on a first base station mounted on a first vehicle is expected to be available to a second base station mounted on a second vehicle may include receiving an index of the second base station mounted on the second vehicle, or an index of a cell served by the second base station mounted on the second vehicle, from the first base station mounted on the first vehicle.

[0288] The indicator may show that the device context stored on the first base station mounted on the first vehicle is expected to be available to the second base station mounted on the second vehicle.

[0289] The network connection release message may include at least one of the following: device context transfer time, an indicator of a second base station mounted on a second vehicle, or an indicator of a cell served by a second base station mounted on a second vehicle.

[0290] Determining that a device context stored on a first base station mounted on a first vehicle is expected to be available to a second base station mounted on a second vehicle may include receiving a paging message from the second base station mounted on the second vehicle.

[0291] The paging message may include at least one of the following: an indicator that the device context is available to the second base station mounted on the second vehicle, or an indicator that the second base station mounted on the second vehicle expects the device to resume network connectivity via the second base station mounted on the second vehicle.

[0292] The device may determine whether it is moving outside or inside the coverage of the first base station mounted on the first vehicle. The device may transmit an indicator to the first base station mounted on the first vehicle, or to the second base station mounted on the second vehicle, indicating whether it is moving outside or inside the coverage of the first base station mounted on the first vehicle.

[0293] The device can determine whether it is moving within or outside the coverage of the second base station mounted on the second vehicle.

[0294] The device may determine that it has high-priority data. The device may attempt to set up a network connection via the second base station mounted on the second vehicle without first attempting to resume the network connection via the second base station mounted on the second vehicle.

[0295] The first vehicle, the second vehicle, and / or the third vehicle may be a satellite, a drone, or a car.

[0296] The first vehicle, the second vehicle, and / or the third vehicle may be stations that have intermittent connectivity to the network.

[0297] Figure 8 shows a schematic representation of a non-volatile memory medium that, when executed by the processor, stores instructions and / or parameters that enable the processor to perform one or more of the steps of the method in Figure 7.

[0298] While exemplary embodiments have been described above, it should be noted that there are several variations and modifications that can be made to the disclosed solutions without departing from the scope of the present invention.

[0299] While the above concepts are discussed in the context of EPS (i.e., LTE), it should be understood that one or more of these concepts may be applicable to other cellular systems, particularly 5GS or next-generation systems.

[0300] While the above concepts are discussed in the context of satellite-based BS, it should be understood that one or more of these concepts may be applicable to BS mounted on other vehicles that provide intermittent CN connectivity, such as drones, cars, or others.

[0301] Thus, embodiments can vary within the scope of the appended claims. Generally, some embodiments can be implemented in hardware or dedicated circuitry, software, logic, or any combination thereof. For example, some embodiments can be implemented in hardware, while others can be implemented in firmware or software that can be executed by a controller, microprocessor, or other computing device, but embodiments are not limited to these. Various embodiments can be shown and described as block diagrams, flowcharts, or using any other graphic representation, but it should be understood that these blocks, devices, systems, techniques, or methods described herein can be implemented in hardware, software, firmware, dedicated circuitry or logic, general-purpose hardware or controllers, or other computing devices, or any combination thereof, as non-limiting examples.

[0302] The embodiments may be implemented by computer software stored in memory and executable by at least one data processor of the entities involved, or by hardware, or by a combination of software and hardware. Furthermore, it should be noted that any procedure, such as that shown in Figure 8, may represent a program step or an interconnected logic circuit, block, and function, or a combination of a program step and a logic circuit, block, and function. The software may be stored on a physical medium such as a memory chip or memory block implemented within a processor, a magnetic medium such as a hard disk or floppy disk, or an optical medium such as a DVD and its data variants, or a CD.

[0303] Memory may be of any type suitable for the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The data processor may be of any type suitable for the local technical environment and may include, in non-limiting examples, one or more of general-purpose computers, dedicated computers, microprocessors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), gate-level circuits, and processors based on multi-core processor architectures.

[0304] Alternatively, or additionally, some embodiments may be implemented using a circuit. The circuit may be configured to perform one or more of the functions and / or method steps described above. The circuit may be provided in a base station and / or communication device.

[0305] As used in this application, the term "circuit" may refer to one or more or all of the following: (a) Hardware-only circuit embodiments (such as embodiments consisting only of analog and / or digital circuits) (b) A combination of hardware circuits and software, for example, (i) combination of analog and / or digital hardware circuits with software / firmware (ii) Any part of a hardware processor, software, and memory having software (including a digital signal processor) that cooperates to cause a device such as a communication device or base station to perform the various functions described above. (c) A processor such as a microprocessor or part of a microprocessor that requires hardware circuitry and / or software (e.g., firmware) for operation, but the software may not be present if it is not required for operation.

[0306] This definition of circuit applies to all uses of this term in this application, including in any claim. Further examples may include, as used herein, embodiments of a mere hardware circuit or processor (or multiple processors), or a portion of a hardware circuit or processor, and its (or their) accompanying software and / or firmware. The term circuit also includes, for example, integrated devices.

[0307] The foregoing description has provided a complete and useful description of several embodiments as illustrative and non-limiting examples. However, when read in conjunction with the accompanying drawings and the accompanying claims, various modifications and adaptations may become apparent to those skilled in the art in light of the foregoing description. However, all such modifications and similar modifications of the teachings still fall within the scope defined in the accompanying claims.

Claims

1. Interrupting the network connection via the first base station mounted on the first vehicle, Determining that the device context stored on the first base station mounted on the first vehicle is expected to be available to the second base station mounted on the second vehicle, Attempting to resume the network connection via the second base station mounted on the second vehicle. A device equipped with means for that purpose.

2. The system includes means for receiving a network connection release message from the first base station mounted on the first vehicle, Attempting to resume the network connection via the second base station mounted on the second vehicle, The apparatus according to claim 1, comprising transmitting a network connection resumption message to the second base station mounted on the second vehicle.

3. The network connection release message includes an identifier associated with the device context, The apparatus according to claim 2, wherein the network connection resumption message includes the identifier associated with the apparatus context.

4. The apparatus according to claim 2, further comprising means for receiving a network connection resumption completion message from the second base station mounted on the second vehicle.

5. To detect failure to receive a network connection resumption completion message from the second base station mounted on the second vehicle, The identifier associated with the device context is stored on the device. The apparatus according to claim 3, comprising means for the purpose of

6. The apparatus according to claim 5, further comprising means for transmitting a network connection setup message, which does not include the identifier associated with the apparatus context, to the second base station mounted on the second vehicle.

7. Determining that the device context stored on the first base station mounted on the first vehicle is expected to be available to the second base station mounted on the second vehicle is: The apparatus according to claim 2, comprising determining that the device context transfer time has expired since the time the network connection was interrupted.

8. Determining that the device context stored on the first base station mounted on the first vehicle is expected to be available to the second base station mounted on the second vehicle is: The apparatus according to claim 7, comprising receiving an indicator of a second base station mounted on a second vehicle, or an indicator of a cell serviced by the second base station mounted on a second vehicle, from the first base station mounted on the first vehicle.

9. The aforementioned network connection release message, The device context transfer time, The indicator of the second base station mounted on the second vehicle, or The indicator of the cell serviced by the second base station mounted on the second vehicle, The apparatus according to claim 8, comprising at least one of the following.

10. Determining that the device context stored on the first base station mounted on the first vehicle is expected to be available to the second base station mounted on the second vehicle is: The apparatus according to claim 1, comprising receiving a paging message from the second base station mounted on the second vehicle.

11. The aforementioned paging message, An indicator showing that the device context is available to the second base station mounted on the second vehicle, or An indicator indicating that the second base station mounted on the second vehicle expects the device to resume the network connection via the second base station mounted on the second vehicle. The apparatus according to claim 10, comprising at least one of the following.

12. Determining that the device has moved outside the coverage of the first base station mounted on the first vehicle, or that the first base station mounted on the first vehicle has moved so that the device is outside its coverage, Transmitting an indicator to the first base station mounted on the first vehicle, or to the second base station mounted on the second vehicle, that the device is moving outside the coverage of the first base station mounted on the first vehicle, or that the first base station mounted on the first vehicle is moving so that the device is outside its coverage. The apparatus according to any one of claims 1 to 11, comprising means for the purpose of

13. The apparatus according to claim 12, further comprising means for determining that the device is moving within the coverage of the second base station mounted on the second vehicle, or that the second base station mounted on the second vehicle is moving so that the device is within its coverage.

14. It is a method, Interrupting the network connection via the first base station mounted on the first vehicle, Determining that the device context stored on the first base station mounted on the first vehicle is expected to be available to the second base station mounted on the second vehicle, Attempting to resume the network connection via the second base station mounted on the second vehicle. Methods that include...

15. A computer program that, when executed on one or more processors, includes computer-executable instructions that perform the steps of the method according to claim 14.

Images