U.S. patent application number 16/181186 was filed with the patent office on 2019-05-09 for device and method of handling an evolved packet system bearer context.
The applicant listed for this patent is HTC Corporation. Invention is credited to Chih-Hsiang Wu.
Application Number | 20190141591 16/181186 |
Document ID | / |
Family ID | 64267591 |
Filed Date | 2019-05-09 |
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United States Patent
Application |
20190141591 |
Kind Code |
A1 |
Wu; Chih-Hsiang |
May 9, 2019 |
Device and Method of Handling an Evolved Packet System Bearer
Context
Abstract
A method for handling an EPS bearer context comprises
transmitting a first protocol data unit (PDU) Session identity (ID)
to a long-term evolution (LTE) network; receiving a first EPS
bearer ID identifying a first EPS bearer, from the LTE network;
configuring a first data radio bearer (DRB) associated to the first
EPS bearer ID, with the LTE network; communicating data via the
first DRB with the LTE network; connecting to a new radio (NR)
network and disconnecting from the LTE network; keeping the first
EPS bearer ID and the first PDU Session ID; configuring a second
DRB associated to the first PDU Session ID, with the NR network;
connecting to the LTE network and disconnecting from the NR
network; keeping the first EPS bearer ID and the first PDU Session
ID; and configuring a third DRB associated to the first EPS bearer
ID.
Inventors: |
Wu; Chih-Hsiang; (Taoyuan
City, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HTC Corporation |
Taoyuan City |
|
TW |
|
|
Family ID: |
64267591 |
Appl. No.: |
16/181186 |
Filed: |
November 5, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62582962 |
Nov 8, 2017 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 36/04 20130101;
H04W 36/0066 20130101; H04W 36/0022 20130101 |
International
Class: |
H04W 36/04 20060101
H04W036/04; H04W 36/00 20060101 H04W036/00 |
Claims
1. A communication device for handling an evolved packet system
(EPS) bearer context, comprising: at least one storage device; and
at least one processing circuit, coupled to the at least one
storage device, wherein the at least one storage device stores, and
the at least one processing circuit is configured to execute
instructions of: transmitting a first protocol data unit (PDU)
Session identity (ID) to a long-term evolution (LTE) network;
receiving a first EPS bearer ID identifying a first EPS bearer,
from the LTE network, wherein the first EPS bearer ID is associated
with the first PDU Session ID; configuring a first data radio
bearer (DRB) associated to the first EPS bearer ID, with the LTE
network; communicating data via the first DRB with the LTE network;
connecting to a new radio (NR) network and disconnecting from the
LTE network; keeping the first EPS bearer ID and the first PDU
Session ID, when connecting to the NR network and disconnecting
from the LTE network; configuring a second DRB associated to the
first PDU Session ID, with the NR network; connecting to the LTE
network and disconnecting from the NR network; keeping the first
EPS bearer ID and the first PDU Session ID, when connecting to the
LTE network and disconnecting from the NR network; and configuring
a third DRB associated to the first EPS bearer ID, when connecting
to the LTE network and disconnecting from the NR network.
2. The communication device of claim 1, wherein the instructions
further comprise: connecting to the NR network and disconnecting
from the LTE network in response to a handover, a cell selection or
reselection, or a redirection; and connecting to the LTE network
and disconnecting from the NR network in response to the handover,
the cell selection or reselection, or the redirection.
3. The communication device of claim 2, wherein the instructions
further comprise: receiving a handover command from a first BS for
the handover, wherein the handover command configures the
communication device to hand over to a first cell of a second BS
and configures the second DRB; connecting to the first cell of the
second BS and configuring the second DRB according to the handover
command; transmitting a handover complete message via the first
cell to the second BS; communicating data via the second DRB with
the second BS in the NR network; and keeping the first EPS bearer
ID and the first PDU Session ID, when connecting to the NR network
according to the handover command.
4. The communication device of claim 2, wherein the instructions
further comprise: receiving a redirection command from a first BS
for the redirection, wherein the redirection command indicates a
cell of the NR network, a frequency of the NR network or selecting
the NR network; entering an idle mode and connecting to the cell of
the NR network according to the redirection command; receiving a
DRB configuration from a second BS in the NR network; and
configuring the second DRB according to the DRB configuration.
5. The communication device of claim 1, wherein the instructions
further comprise: transmitting a second PDU Session ID to the LTE
network; receiving a second EPS bearer ID identifying a second EPS
bearer, from the LTE network, wherein the second EPS bearer ID is
associated with the second PDU Session ID; configuring a fourth DRB
associated to the second EPS bearer ID, with the LTE network;
communicating data via the fourth DRB with the LTE network;
connecting to the NR network and disconnecting from the LTE
network; and keeping the first EPS bearer ID and the first PDU
Session ID and releasing the second EPS bearer ID and the second
PDU Session ID, when connecting to the NR network and disconnecting
from the LTE network.
6. A communication device for handling an evolved packet system
(EPS) bearer context, comprising: at least one storage device; and
at least one processing circuit, coupled to the at least one
storage device, wherein the at least one storage device stores, and
the at least one processing circuit is configured to execute
instructions of: transmitting a first protocol data unit (PDU)
Session identity (ID) to a long-term evolution (LTE) network;
receiving a first EPS bearer ID identifying a first EPS bearer,
from the LTE network, wherein the first EPS bearer ID is associated
with the first PDU Session ID; configuring a first data radio
bearer (DRB) associated to the first EPS bearer ID, with the LTE
network; communicating data via the first DRB with the LTE network;
receiving a handover command from the LTE network, wherein the
handover command indicates the communication device to hand over to
a new radio (NR) network; keeping the first EPS bearer ID and the
first PDU Session ID, when the handover command comprises a DRB
configuration associated to the first PDU Session ID; and releasing
the first EPS bearer ID, when the handover command does not
comprise the DRB configuration.
7. The communication device of claim 6, wherein the instructions
further comprise: transmitting a handover complete message via a
cell to a base station (BS).
8. The communication device of claim 6, wherein the instructions
further comprise: configuring a first signaling radio bearer (SRB)
with the LTE network; and receiving the handover command via the
first SRB from the LTE network.
9. The communication device of claim 8, wherein the instructions
further comprise: configuring a second SRB with the NR network,
when connecting to the NR network and disconnecting from the LTE
network; and transmitting a handover complete message via the
second SRB to the NR network, in response to the handover command.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 62/582,962 filed on Nov. 8, 2017, which is
incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0002] The present invention relates to a device and a method used
in a wireless communication system, and more particularly, to a
device and a method of handling an evolved packet system (EPS)
bearer context in a wireless communication system.
2. Description of the Prior Art
[0003] Recently, a fifth generation (5G) system (or called next
generation system) has been developed by the 3rd Generation
Partnership Project (3GPP). To provide seamless service continuity
for a communication device moving between an evolved packet system
(EPS) and the 5G system, an inter-system mobility between the two
systems is an issue to be solved.
SUMMARY OF THE INVENTION
[0004] The present invention therefore provides a communication
device for handling an EPS bearer context to solve the
abovementioned problem.
[0005] A communication device for handling an EPS bearer context
comprises at least one storage device for storing instructions and
at least one processing circuit coupled to the at least one storage
device. The at least one processing circuit is configured to
execute the instructions stored in the at least one storage device.
The instructions comprise transmitting a first protocol data unit
(PDU) Session identity (ID) to a LTE network; receiving a first EPS
bearer ID identifying a first EPS bearer, from the LTE network,
wherein the first EPS bearer ID is associated with the first PDU
Session ID; configuring a first data radio bearer (DRB) associated
to the first EPS bearer ID, with the LTE network; communicating
data via the first DRB with the LTE network; connecting to a NR
network and disconnecting from the LTE network; keeping the first
EPS bearer ID and the first PDU Session ID, when connecting to the
NR network and disconnecting from the LTE network; configuring a
second DRB associated to the first PDU Session ID, with the NR
network; connecting to the LTE network and disconnecting from the
NR network; keeping the first EPS bearer ID and the first PDU
Session ID, when connecting to the LTE network and disconnecting
from the NR network; and configuring a third DRB associated to the
first EPS bearer ID, when connecting to the LTE network and
disconnecting from the NR network.
[0006] These and other objectives of the present invention will no
doubt become obvious to those of ordinary skill in the art after
reading the following detailed description of the preferred
embodiment that is illustrated in the various figures and
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a schematic diagram of a wireless communication
system according to an example of the present invention.
[0008] FIG. 2 is a schematic diagram of a communication device
according to an example of the present invention.
[0009] FIG. 3 is a flowchart of a process according to an example
of the present invention.
[0010] FIG. 4 is a flowchart of a process according to an example
of the present invention.
[0011] FIG. 5 is a flowchart of a process according to an example
of the present invention.
[0012] FIG. 6 is a flowchart of a process according to an example
of the present invention.
DETAILED DESCRIPTION
[0013] In FIG. 1, a network and communication devices are simply
utilized for illustrating the structure of a wireless communication
system 10. Practically, the network includes at least one of a
long-term evolution (LTE) network, an evolved LTE network, a new
radio (NR) network and a sixth generation (6G) network. The 6G
radio communication technology may employ orthogonal
frequency-division multiplexing (OFDM) or non-OFDM, a wider
bandwidth (e.g., 1 GHz, 2 GHz or 5 GHz) and a transmission time
interval (TTI) shorter than 1 ms (e.g., 1, 2, 3 or 4 OFDM symbols,
100, or 200 us) for communication between the communication devices
and the 6G base station (BS).
[0014] A communication device may be a user equipment (UE), a
mobile phone, a laptop, a tablet computer, an electronic book, a
portable computer system, a vehicle, or an aircraft. In addition,
the network and the communication device can be seen as a
transmitter or a receiver according to direction of transmission
(i.e., transmission direction), e.g., for an uplink (UL), the
communication device is the transmitter and the network is the
receiver, and for a downlink (DL), the network is the transmitter
and the communication device is the receiver.
[0015] In FIG. 2, a communication device 20 may be a communication
device or the network shown in FIG. 1, but is not limited herein.
The communication device 20 may include at least one processing
circuit 200 of which each may be a microprocessor or Application
Specific Integrated Circuit (ASIC), at least one storage device 210
and at least one communication interfacing device 220. The at least
one storage device 210 may be any data storage device that may
store program codes 214 accessed and executed by the at least one
processing circuit 200. Examples of the at least one storage device
210 include but are not limited to a subscriber identity module
(SIM), read-only memory (ROM), flash memory, random-access memory
(RAM), hard disk, optical data storage device, non-volatile storage
device, non-transitory computer-readable medium (e.g., tangible
media), etc. The at least one communication interfacing device 220
includes at least one transceiver used to transmit and receive
signals (e.g., data, messages and/or packets) according to
processing results of the at least one processing circuit 200.
[0016] In the following examples, a UE is used for representing a
communication device in FIG. 1, to simplify the illustration of the
examples.
[0017] A process 30 in FIG. 3 is utilized in a UE to handle an
evolved packet system (EPS) bearer context, and includes the
following steps:
[0018] Step 300: Start.
[0019] Step 302: Transmit a first protocol data unit (PDU) Session
identity (ID) to a LTE network.
[0020] Step 304: Receive a first EPS bearer ID identifying a first
EPS bearer, from the LTE network, wherein the first EPS bearer ID
is associated with the first PDU Session ID.
[0021] Step 306: Configure a first data radio bearer (DRB)
associated to the first EPS bearer ID, with the LTE network.
[0022] Step 308: Communicate data via the first DRB with the LTE
network.
[0023] Step 310: Connect to a NR network and disconnect from the
LTE network.
[0024] Step 312: Keep the first EPS bearer ID and the first PDU
Session ID, when connecting to the NR network and disconnecting
from the LTE network.
[0025] Step 314: Configure a second DRB associated to the first PDU
Session ID, with the NR network.
[0026] Step 316: Connect to the LTE network and disconnect from the
NR network.
[0027] Step 318: Keep the first EPS bearer ID and the first PDU
Session ID, when connecting to the LTE network and disconnecting
from the NR network.
[0028] Step 320: Configure a third DRB associated to the first EPS
bearer ID, when connecting to the LTE network and disconnecting
from the NR network.
[0029] Step 322: End.
[0030] According to the process 30, the UE keeps the first EPS
bearer ID and the first PDU Session ID, when connecting to the NR
network and connecting back to the LTE network. That is, the UE
keeps the first EPS bearer ID and the first PDU Session ID when
moving back and forth between the LTE network and the NR network.
If the UE does not keep the first EPS bearer ID when connecting to
the NR network and disconnecting from the LTE network, the UE fails
to apply a configuration of the third DRB received from the LTE
network since the UE does not recognize the first EPS bearer ID in
the configuration of the third DRB. Thus, the UE fails to configure
(or establish) the third DRB according to the configuration of the
third DRB, and consequently, the UE cannot communicate (e.g.,
transmit or receive) data with (e.g., to or from) the LTE
network.
[0031] Realization of the process 30 is not limited to the above
description. The following examples may be applied to the process
30.
[0032] In one example, the UE receives a first DRB configuration
from the LTE network, and configures the first DRB according to the
first DRB configuration. In one example, the EPS bearer ID is
associated with the PDU Session ID by the UE.
[0033] In one example, the UE connects to a first cell of a first
BS in the LTE network. The UE communicates (e.g., transmits or
receives) data via (e.g., on or over) the first DRB with (e.g., to
or from) the first BS. Then, the UE connects to a second cell of a
second BS in the NR network and disconnects from the first cell of
the first BS in the LTE network in response to (or due to) a
handover, a cell selection or reselection or a redirection. In case
of the handover, the UE receives a handover command (e.g., a radio
resource control (RRC) Connection Reconfiguration or a RRC
Reconfiguration) from the first BS. The handover command configures
the UE to hand over to the second cell of the second BS and
configures the second DRB. The UE connects to the second cell of
the second BS and configures the second DRB according to the
handover command. The UE transmits a handover complete message
(e.g., a RRC Connection Reconfiguration Complete or a RRC
Reconfiguration Complete) via the second cell to the second BS, and
communicates data via the second DRB with the second BS in the NR
network. The UE keeps (or maintains) the first EPS bearer ID and
the first PDU Session ID, when connecting to the NR network
according to the handover command. In case of the cell selection or
reselection, the UE selects the second cell of the NR network to
camp from the first cell. In case of the redirection, the UE
receives a redirection command from the first BS via the first
cell. The redirection command indicates the second cell, a
frequency of the NR network or selecting the NR network. The UE
enters an idle mode and selects the second cell according to the
redirection command. The UE receives a second DRB configuration
from the second BS and configures the second DRB according to the
second DRB configuration, when connecting to the second BS via the
second cell in a connected state from an idle state in the NR
network.
[0034] In one example, the UE connects back to a third cell of a
third BS in the LTE network and disconnects from the second cell of
the second BS in the NR network in response to (or due to) a
handover, a cell selection or reselection or a redirection. In case
of the handover, the UE receives a handover command (e.g., a RRC
Connection Reconfiguration or a RRC Reconfiguration) from the
second cell. The handover command configures the UE to hand over to
the third cell and configures the third DRB. The UE connects to the
third BS via the third cell and configures the third DRB according
to the handover command. The UE communicates data via the third DRB
with the third BS. The UE keeps (or maintains) the first EPS bearer
ID and the first PDU Session ID, when connecting to the LTE network
according to the handover command. In case of the cell selection or
reselection, the UE selects the third cell to camp from the second
cell. In case of the redirection, the UE receives a redirection
command from the second BS via the second cell. The redirection
command indicates the third cell of the LTE network, a frequency of
the LTE network or selecting the LTE network. The UE enters an idle
mode and connects to the third cell according to the redirection
command. The UE receives a third DRB configuration from the third
BS and configures the third DRB according to the third DRB
configuration, when connecting to the third BS via the third cell
in a connected state from an idle state in the NR network. The
first BS and the third BS are the same BS or different BSs. The
first cell and the third cell are the same cell or different
cells.
[0035] In one example, the UE considers that the first PDU Session
ID and the first EPS bearer ID are valid, when keeping the first
EPS bearer ID and the first PDU Session ID. The UE uses the kept
first PDU Session ID to communicate with the NR network, and uses
the kept first EPS bearer ID to communicate with the LTE
network.
[0036] In one example, since the UE keeps the first PDU Session ID,
the UE considers that a DRB configuration including the first PDU
Session ID and configuring a DRB associated to the first PDU
Session ID are valid, when the UE receives the DRB configuration
(e.g., in a RRC Reconfiguration message) from the NR network
directly or via the LTE network. In one example, the DRB
configuration indicates that the DRB is a default DRB. For example,
the DRB configuration includes a field or an information element
(IE) indicating that the DRB is a default DRB.
[0037] In one example, since the UE keeps the first EPS bearer ID,
the UE considers that a DRB configuration including the EPS bearer
ID and configuring a DRB associated to the EPS bearer ID is valid,
when the UE receives the DRB configuration (e.g., in a RRC
Connection Reconfiguration message) from the LTE network directly
or via the NR network.
[0038] In one example, since the UE keeps the first PDU Session ID,
the UE transmits a first non-access stratum (NAS) message including
the first PDU Session ID to the NR network, when or after the UE
connects to the NR network and disconnects from the LTE network.
For example, the first NAS message is a Mobility Management (MM)
message (e.g., a Registration Request, a Registration Complete or a
Service Request) or a Session Management (SM) message (e.g., a PDU
Session Release Request or a PDU Session Modification Request).
[0039] In one example, since the UE keeps the first PDU Session ID,
the UE receives a second NAS message including the first PDU
Session ID from the NR network, when or after the UE connects to
the NR network and disconnects from the LTE network. For example,
the second NAS message is a MM message (e.g. , a Registration
Accept, a Service Accept or a UE Configuration Update Command) or a
SM message (e.g., a PDU Session Release Accept or a PDU Session
Modification Accept). The second NAS message includes or does not
include the first EPS bearer identity.
[0040] In one example, since the UE keeps the first EPS bearer
identity, the UE transmits a third NAS message including the first
EPS bearer ID to the LTE network, when or after the UE connects to
the LTE network and disconnects from the NR network. For example,
the third NAS message is a MM message (e.g. , a Tracking Area
Update Request or a Tracking Area Update Complete) or a SM message
(e.g., a packet data network (PDN) Disconnect Request, a Bearer
Resource Allocation Request, a Bearer Resource Modification
Request, an Activate Dedicated EPS Bearer Context Accept, an
Activate Dedicated EPS Bearer Context Reject, a Modify EPS Bearer
Context Accept, a Modify EPS Bearer Context Reject or a Deactivate
EPS Bearer Context Accept).
[0041] In one example, since the UE keeps the first EPS bearer ID,
the UE receives a fourth NAS message including the first EPS bearer
identity from the LTE network, when or after the UE connects to the
LTE network and disconnects from the NR network. For example, the
fourth NAS message is a MM message (e.g. , a Tracking Area Update
Accept) or a SM message (e.g., a Deactivate EPS Bearer Context
Request, a PDN Disconnect Reject, an Activate Dedicated EPS Bearer
Context Request, a Modify EPS Bearer Context Request, a Bearer
Resource Allocation Reject or a Bearer Resource Modification
Reject). The fourth NAS message includes or does not include the
first PDU Session ID.
[0042] In one example, the UE transmits the first PDU Session ID in
a SM message (e.g., a PDN Connectivity Request message) to the LTE
network. The UE receives the first EPS identity in a SM message
(e.g. , an Activate Default EPS Bearer Context Request) from the
LTE network.
[0043] In one example, if the second NAS message is the
Registration Accept message which does not include the first PDU
Session ID, the UE releases the first PDU Session ID and the first
EPS bearer ID. If the second NAS message is the Registration Accept
message which does not include the first PDU Session ID, the UE
determines that an EPS bearer context which is established and
associated to the EPS bearer ID by the LTE network has been
released by the NR network. If the second NAS message is the
Registration Accept message which does not include the first PDU
Session ID, the UE determines that a PDU Session associated to the
PDU Session ID is released or is not established or does not exist
in the NR network. That is, the NR network does not reestablish the
PDU Session associated to the EPS bearer context for the UE.
[0044] A process 40 in FIG. 4 is utilized in a UE to handle an EPS
bearer context, and includes the following steps:
[0045] Step 400: Start.
[0046] Step 402: Transmit a first PDU Session ID and a second PDU
Session ID to a LTE network.
[0047] Step 404: Receive a first EPS bearer ID identifying a first
EPS bearer, from the LTE network, wherein the first EPS bearer ID
is associated with the first PDU Session ID.
[0048] Step 406: Configure a first DRB associated to the first EPS
bearer ID, with the LTE network.
[0049] Step 408: Communicate data via the first DRB with the LTE
network.
[0050] Step 410: Receive a second EPS bearer ID identifying a
second EPS bearer, from the LTE network, wherein the second EPS
bearer ID is associated with the second PDU Session ID.
[0051] Step 412: Configure a second DRB associated to the second
EPS bearer ID, with the LTE network.
[0052] Step 414: Communicate data via the second DRB with the LTE
network.
[0053] Step 416: Connect to a NR network and disconnect from the
LTE network.
[0054] Step 418: Keep the first EPS bearer ID and the first PDU
Session ID and release the second EPS bearer ID and the second PDU
Session ID, when connecting to the NR network and disconnecting
from the LTE network.
[0055] Step 420: End.
[0056] As described above, the UE connects to the NR network and
disconnects from the LTE network in response to (or due to) the
cell selection or the cell reselection, the handover or the
redirection. In one example, the UE keeps the first EPS bearer ID
and the first PDU Session ID and releases the second EPS bearer ID
and the second PDU Session ID according to the handover command.
The handover command configures a third DRB associated to the first
PDU Session ID but does not configure a DRB associated to the
second PDU Session ID. For example, the handover command includes a
second DRB configuration configuring the third DRB and includes the
first PDU Session ID, but does not include a DRB configuration
configuring a DRB and does not include the second PDU Session
ID.
[0057] In one example, the UE keeps the first EPS bearer ID and the
first PDU Session ID and releases the second EPS bearer ID and the
second PDU Session ID according to a NAS message received from the
NR network (e.g., the second NAS message described above). For
example, the NAS message is the Registration Accept, and includes
the first PDU Session ID but does not include the second PDU
Session ID.
[0058] In one example, the UE transmits the first PDU Session ID
and the second PDU Session ID in different SM messages (e.g., PDN
Connectivity Request messages) to the LTE network. The UE receives
the first EPS bearer ID and second EPS bearer ID in different SM
messages (e.g., Activate Default EPS Bearer Context Request
messages).
[0059] Examples described for the process 30 can be applied to the
process 40, and are not narrated herein.
[0060] A process 50 in FIG. 5 is utilized in a UE to handle an EPS
bearer context, and includes the following steps:
[0061] Step 500: Start.
[0062] Step 502: Transmit a first PDU Session ID to a LTE
network.
[0063] Step 504: Receive a first EPS bearer ID identifying a first
EPS bearer, from the LTE network, wherein the first EPS bearer ID
is associated with the first PDU Session ID.
[0064] Step 506: Configure a first DRB associated to the first EPS
bearer ID, with the LTE network.
[0065] Step 508: Communicate data via the first DRB with the LTE
network.
[0066] Step 510: Receive a first handover command from the LTE
network, wherein the first handover command indicates the UE to
hand over to a NR network.
[0067] Step 512: Keep the first EPS bearer ID and the first PDU
Session ID, when the first handover command comprises a first DRB
configuration associated to the first PDU Session ID.
[0068] Step 514: Release the first EPS bearer ID, when the first
handover command does not comprise the first DRB configuration.
[0069] Step 516: End.
[0070] According to the process 50, the UE keeps an EPS bearer ID
associated to a PDU Session ID if a received handover command
includes a DRB configuration associated to the PDU Session ID, and
the UE releases the EPS bearer ID if the received handover command
does not include a DRB configuration associated to the PDU Session
ID. That is, the UE determines that an EPS bearer context
identified by the first EPS bearer ID is kept, when handing over to
the NR network from the LTE network. The UE determines that the EPS
bearer context is released when handing over to the NR network from
the LTE network.
[0071] Realization of the process 50 is not limited to the above
description. The following examples may be applied to the process
50.
[0072] In one example, the UE releases the first PDU Session ID,
when the first handover command does not include the first DRB
configuration. That is, the UE determines that no PDU Session
identified by the first PDU Session ID has been established between
the UE and the NR network.
[0073] In one example, the UE transmits a second PDU Session ID to
the LTE network. The UE receives a second EPS bearer ID identifying
a second EPS bearer, from the LTE network, wherein the second EPS
bearer ID is associated with the second PDU Session ID. The UE
configures a second DRB associated to the second EPS bearer ID,
with the LTE network. The UE communicates data via the second DRB
with the LTE network. The UE receives a second handover command
from the LTE network, wherein the second handover command indicates
the UE to hand over to the NR network, and includes a second DRB
configuration configuring a second DRB associated to the first PDU
Session ID but does not include a third DRB configuration
associated to the second PDU Session ID. The UE keeps the first EPS
bearer ID and the first PDU Session ID and releases the second EPS
bearer ID and the second PDU Session ID, according to the second
handover command. The first handover command and the second
handover command are the same handover command or different
handover commands.
[0074] Examples described for the processes 30-40 can be applied to
the process 50, and are not narrated herein.
[0075] A process 60 in FIG. 6 is utilized in a UE to handle an EPS
bearer context, and includes the following steps:
[0076] Step 600: Start.
[0077] Step 602: Transmit a first PDU Session ID and a second PDU
Session ID to a LTE network.
[0078] Step 604: Receive a first EPS bearer ID identifying a first
EPS bearer, from the LTE network, wherein the first EPS bearer ID
is associated with the first PDU Session ID.
[0079] Step 606: Configure a first DRB associated to the first EPS
bearer ID, with the LTE network.
[0080] Step 608: Communicate data via the first DRB with the LTE
network.
[0081] Step 610: Receive a second EPS bearer ID identifying a
second EPS bearer, from the LTE network, wherein the second EPS
bearer ID is associated with the second PDU Session ID.
[0082] Step 612: Configure a second DRB associated to the second
EPS bearer ID, with the LTE network.
[0083] Step 614: Communicate data via the second DRB with the LTE
network.
[0084] Step 616: Receive a handover command from the LTE network,
wherein the handover command indicates the UE to hand over to a NR
network and comprises a third DRB configuration configuring a third
DRB associated with the first PDU Session ID but does not comprise
a DRB configuration configuring a fourth DRB associated with the
second PDU Session ID.
[0085] Step 618: Keep the first EPS bearer ID and the first PDU
Session ID and release the second EPS bearer ID and the second PDU
Session ID, according to the handover command.
[0086] Step 620: End.
[0087] Examples described for the processes 30-50 can be applied to
the process 60, and are not narrated herein.
[0088] The following examples can be applied to any of the
processes 30-60.
[0089] In one example, the UE configures a first signaling radio
bearer (SRB) with the LTE network. The UE receives a handover
command via the first SRB. That is, the UE has the first SRB
configured to communicate with (e.g., transmit to or receive from)
a BS of the LTE network. The UE configures a second SRB with the NR
network, when connecting to the NR network and disconnecting from
the LTE network. The UE transmits a handover complete message
(e.g., a RRC Reconfiguration Complete) on the second SRB to the NR
network in response to the handover command.
[0090] Those skilled in the art should readily make combinations,
modifications and/or alterations on the abovementioned description
and examples. For example, the skilled person easily makes new
embodiments of the network based on the embodiments and examples of
the UE, and makes new embodiments of the UE based on the
embodiments and examples of the network. The abovementioned
description, steps and/or processes including suggested steps can
be realized by means that could be hardware, software, firmware
(known as a combination of a hardware device and computer
instructions and data that reside as read-only software on the
hardware device), an electronic system, or combination thereof. An
example of the means may be the communication device 20. Any of the
above processes and examples above may be compiled into the program
codes 214.
[0091] To sum up, the present invention provides methods and
devices for handling an EPS bearer context. The UE keeps the EPS
bearer ID when changing a camped network so that the UE can apply a
configuration received from the original network. Thus, the problem
in the art is solved.
[0092] Those skilled in the art will readily observe that numerous
modifications and alterations of the device and method may be made
while retaining the teachings of the invention. Accordingly, the
above disclosure should be construed as limited only by the metes
and bounds of the appended claims.
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