U.S. patent application number 16/373895 was filed with the patent office on 2019-10-10 for handling qos flow without a mapping data radio bearer.
The applicant listed for this patent is MEDIATEK INC.. Invention is credited to Chi-Hsien Chen, Chia-Chun Huang-Fu, Shang-Ru Mo.
Application Number | 20190313262 16/373895 |
Document ID | / |
Family ID | 68096634 |
Filed Date | 2019-10-10 |
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United States Patent
Application |
20190313262 |
Kind Code |
A1 |
Huang-Fu; Chia-Chun ; et
al. |
October 10, 2019 |
Handling QoS Flow without a Mapping Data Radio Bearer
Abstract
A PDU session and QoS flow handling mechanism is proposed when a
QoS flow of a PDU session does not have a mapping DRB after a
handover or a service request procedure. If the QoS flow is
associated with a default QoS rule, the UE can locally release the
PDU session, initiate a PDU session release procedure, send a 5GSM
status message with proper cause, or assume the PDU session is not
reactivated. On the other hand, if the QoS flow is not associated
with a default QoS rule, the UE can locally delete the QoS flow,
delete the QoS flow by using a PDU session modification procedure,
or send a 5GSM status message with proper cause.
Inventors: |
Huang-Fu; Chia-Chun;
(Hsin-Chu, TW) ; Chen; Chi-Hsien; (Hsin-Chu,
TW) ; Mo; Shang-Ru; (Hsin-Chu, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MEDIATEK INC. |
Hsin-Chu |
|
TW |
|
|
Family ID: |
68096634 |
Appl. No.: |
16/373895 |
Filed: |
April 3, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62655137 |
Apr 9, 2018 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 67/141 20130101;
H04L 69/22 20130101; H04W 60/06 20130101; H04W 24/02 20130101; H04W
36/0033 20130101; H04L 47/2441 20130101; H04W 36/0011 20130101;
H04W 36/0022 20130101; H04W 28/0268 20130101; H04L 67/143 20130101;
H04W 28/24 20130101; H04W 76/38 20180201; H04W 84/042 20130101;
H04W 88/02 20130101; H04L 47/6295 20130101; H04W 36/14 20130101;
H04L 47/2491 20130101 |
International
Class: |
H04W 24/02 20060101
H04W024/02; H04L 29/08 20060101 H04L029/08 |
Claims
1. A method, comprising: receiving a radio resource control (RRC)
reconfiguration by a user equipment (UE) in a mobile communication
network, wherein the UE is configured with one or more Protocol
data unit (PDU) sessions, and wherein an activated PDU session is
configured with one or more QoS flows; detecting that a QoS flow of
the activated PDU session has no mapping data radio bearer (DRB)
available based on the RRC reconfiguration; performing a first PDU
session and QoS flow handling when the QoS flow is associated with
a default QoS rule; and performing a second PDU session and QoS
flow handing when the QoS flow is not associated with the default
QoS rule.
2. The method of claim 1, wherein the RRC reconfiguration is due to
an intra-system or inter-system handover procedure.
3. The method of claim 1, wherein RRC reconfiguration is due to a
UE-initiated or a network-initiated service request procedure.
4. The method of claim 1, wherein the first PDU session and QOS
handling involves releasing the activated PDU session locally by
the UE.
5. The method of claim 1, wherein the first PDU session and QoS
flow handling involves initiating a PDU session release procedure
with the network.
6. The method of claim 1, wherein the first PDU session and QoS
flow handling involves the UE treating the activated PDU session as
not reactivated.
7. The method of claim 1, wherein the second PDU session and QoS
flow handling involves deleting the QoS flow locally by the UE or
explicitly by using a PDU session modification procedure.
8. The method of claim 1, wherein the second PDU session and QoS
flow handling involves the UE treating the QoS flow as not
reactivated.
9. The method of claim 1, wherein the UE detects that the QoS flow
is mapped to a DRB but the DRB is not established after the RRC
reconfiguration.
10. The method of claim 1, wherein the UE detects that a mapping
between the QoS flow and any established DRB is missing and there
is no default DRB available after the RRC reconfiguration.
11. A User Equipment (UE), comprising: a receiver that receives a
radio resource control (RRC) reconfiguration in a mobile
communication network, wherein the UE is configured with one or
more Protocol data unit (PDU) sessions, and wherein an activated
PDU session is configured with one or more QoS flows; a configure
and control circuit that detects that a QoS flow of the activated
PDU session has no mapping data radio bearer (DRB) available based
on the RRC reconfiguration; and a QoS flow handling circuit that
performs a first PDU session and QoS flow handling when the QoS
flow is associated with a default QoS rule, otherwise performing a
second PDU session and QoS flow handing when the QoS flow is not
associated with the default QoS rule.
12. The UE of claim 11, wherein the RRC reconfiguration is due to
an intra-system or inter-system handover procedure.
13. The UE of claim 11, wherein RRC reconfiguration is due to a
UE-initiated or a network-initiated service request procedure.
14. The UE of claim 11, wherein the first PDU session and QOS
handling involves releasing the activated PDU session locally by
the UE.
15. The UE of claim 11, wherein the first PDU session and QoS flow
handling involves initiating a PDU session release procedure with
the network.
16. The UE of claim 11, wherein the first PDU session and QoS flow
handling involves the UE treating the activated PDU session as not
reactivated.
17. The UE of claim 11, wherein the second PDU session and QoS flow
handling involves deleting the QoS flow locally by the UE or
explicitly by using a PDU session modification procedure.
18. The UE of claim 11, wherein the second PDU session and QoS flow
handling involves the UE treating the QoS flow as not
reactivated.
19. The UE of claim 11, wherein the UE detects that the QoS flow is
mapped to a DRB but the DRB is not established after the RRC
reconfiguration.
20. The UE of claim 11, wherein the UE detects that a mapping
between the QoS flow and any established DRB is missing and there
is no default DRB available after the RRC reconfiguration.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C. .sctn. 119
from U.S. Provisional Application No. 62/655,137, entitled "5GSM
Enhancement on Interworking", filed on Apr. 9, 2018, the subject
matter of which is incorporated herein by reference.
TECHNICAL FIELD
[0002] The disclosed embodiments relate generally to wireless
communication, and, more particularly, to method of handling
Quality of Service (QoS) flows without a mapping data radio bearer
(DRB) in 5G new radio (NR) systems.
BACKGROUND
[0003] The wireless communications network has grown exponentially
over the years. A Long-Term Evolution (LTE) system offers high peak
data rates, low latency, improved system capacity, and low
operating cost resulting from simplified network architecture. LTE
systems, also known as the 4G system, also provide seamless
integration to older wireless network, such as GSM, CDMA and
Universal Mobile Telecommunication System (UMTS). In LTE systems,
an evolved universal terrestrial radio access network (E-UTRAN)
includes a plurality of evolved Node-Bs (eNodeBs or eNBs)
communicating with a plurality of mobile stations, referred to as
user equipments (UEs). The 3.sup.rd generation partner project
(3GPP) network normally includes a hybrid of 2G/3G/4G systems. The
Next Generation Mobile Network (NGMN) board, has decided to focus
the future NGMN activities on defining the end-to-end requirements
for 5G new radio (NR) systems.
[0004] In 5G, a Protocol Data Unit (PDU) session establishment is a
parallel procedure of a Packet Data Network (PDN) connection
procedure in 4G. A PDU session defines the association between the
UE and the data network that provides a PDU connectivity service.
Each PDU session is identified by a PDU session ID, and may include
multiple QoS flows and QoS rules. In 5G network, QoS flow is the
finest granularity for QoS management to enable more flexible QoS
control. The concept of QoS flow in 5G is like EPS bearer in 4G.
Each QoS flow is identified by a QoS flow ID (QFI) which is unique
within a PDU session. Each QoS rule is identified by a QoS rule ID
(QRI). There can be more than one QoS rule associated with the same
QoS flow. A default QoS rule is required to be sent to the UE for
every PDU session establishment and it is associated with a QoS
flow.
[0005] Each QoS flow needs to be supported by a mapping Data Radio
Bearer (DRB) in Access Stratum (AS) layer. Multiple QoS flows can
be mapped to the same DRB. If there is a default DRB for a PDU
session, then all traffic of QoS flows that have no mapping DRBs
are sent via the default DRB. After an intra-system or inter-system
handover procedure, or after a UE-initiated or network-initiated
service request procedure, the RRC/AS layer may indicate that a QoS
flow is not supported, e.g., the mapping DRB for the QoS flow is
not established, or the mapping for the QoS flow to a DRB is
missing and there is no default DRB available.
[0006] A solution is sought to properly handle PDU session and QoS
flow management when UE cannot find a mapping DRB for a QoS flow of
a PDU session after a handover procedure or a service request
procedure.
SUMMARY
[0007] A PDU session and QoS flow handling mechanism is proposed
when a QoS flow of a PDU session does not have a mapping DRB after
a handover or a service request procedure. If the QoS flow is
associated with a default QoS rule, then all QoS flows of the PDU
session is impacted and corresponding action is thus required for
the PDU session. Specifically, the UE can locally release the PDU
session, initiate a PDU session release procedure, send a 5GSM
status message with proper cause, or assume the PDU session is not
reactivated. On the other hand, if the QoS flow is not associated
with a default QoS rule, then only this particular QoS flow is
impacted and corresponding action is thus required for the QoS
flow. Specifically, the UE can locally delete the QoS flow, delete
the QoS flow by using a PDU session modification procedure, or send
a 5GSM status message with proper cause.
[0008] In one embodiment, a UE receives a radio resource control
(RRC) reconfiguration in a mobile communication network. The UE is
configured with one or more Protocol data unit (PDU) sessions, and
an activated PDU session is configured with one or more QoS flows.
The UE detects that a QoS flow of the activated PDU session has no
mapping data radio bearer (DRB) available based on the RRC
reconfiguration. The UE performs a first PDU session and QoS flow
handling when the QoS flow is associated with a default QoS rule.
The UE performs a second PDU session and QoS flow handing when the
QoS flow is not associated with the default QoS rule. In one
embodiment, the UE locally releases the PDU session, initiates a
PDU session release procedure, sends a 5GSM status message with
proper cause, or assumes the PDU session is not reactivated when
the QoS flow is associated with the default QoS rule. In another
embodiment, the UE locally deletes the QoS flow, deletes the QoS
flow by using a PDU session modification procedure, or sends a 5GSM
status message with proper cause when the QoS flow is not
associated with the default QoS rule.
[0009] Other embodiments and advantages are described in the
detailed description below. This summary does not purport to define
the invention. The invention is defined by the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The accompanying drawings, where like numerals indicate like
components, illustrate embodiments of the invention.
[0011] FIG. 1 illustrates an exemplary 5G network supporting
Quality of Service (QoS) rule management after receiving radio
resource control (RRC) reconfiguration in accordance with one novel
aspect.
[0012] FIG. 2 illustrates simplified block diagrams of a user
equipment (UE) in accordance with embodiments of the current
invention.
[0013] FIG. 3 illustrates a first embodiment of PDU session and QoS
flow handling after a handover procedure in accordance with one
novel aspects.
[0014] FIG. 4 illustrates a flow chart of a novel PDU session and
QoS flow handling when a QoS flow has no mapping DRB after a PDU
session is reactivated.
[0015] FIG. 5 illustrates a second embodiment of PDU session and
QoS flow handling after a UE-initiated service request procedure in
accordance with one novel aspects.
[0016] FIG. 6 illustrates a third embodiment of PDU session and QoS
flow handling after a network-initiated service request procedure
in accordance with one novel aspects.
[0017] FIG. 7 is a flow chart of a method of PDU session and QoS
flow handling in accordance with one novel aspect of the present
invention.
DETAILED DESCRIPTION
[0018] Reference will now be made in detail to some embodiments of
the invention, examples of which are illustrated in the
accompanying drawings.
[0019] FIG. 1 illustrates an exemplary 5G network 100 supporting
Quality of Service (QoS) rule management after receiving radio
resource control (RRC) reconfiguration in accordance with one novel
aspect. 5G new radio (NR) network 100 comprises a user equipment UE
101, a base station gNB 102, an access and mobility management
function (AMF) 103, and a 5G core network 5GC 104. In the example
of FIG. 1, UE 101 and its serving base station gNB 102 belong to
part of a radio access network RAN 120. In Access Stratum (AS)
layer, RAN 120 provides radio access for UE 101 via a radio access
technology (RAT). In Non-Access Stratum (NAS) layer, AMF 103
communicates with gNB 102 and 5GC 104 for access and mobility
management of wireless access devices in 5G network 100. UE 101 may
be equipped with a radio frequency (RF) transceiver or multiple RF
transceivers for different application services via different
RATs/CNs. UE 114 may be a smart phone, a wearable device, an
Internet of Things (IoT) device, and a tablet, etc.
[0020] 5GS networks are packet-switched (PS) Internet Protocol (IP)
networks. This means that the networks deliver all data traffic in
IP packets, and provide users with Always-On IP Connectivity. When
UE joins a 5GS network, a Packet Data Network (PDN) address (i.e.,
the one that can be used on the PDN) is assigned to the UE for its
connection to the PDN. In 4G, EPS has defined a Default EPS Bearer
to provide the IP Connectivity that is Always-On. In 5G, a Protocol
Data Unit (PDU) session establishment procedure is a parallel
procedure of a PDN connection procedure in 4G. A PDU session
defines the association between the UE and the data network that
provides a PDU connectivity service. Each PDU session is identified
by a PDU session ID, and may include multiple QoS flows and QoS
rules. In 5G network, QoS flow is the finest granularity for QoS
management to enable more flexible QoS control. The concept of QoS
flow in 5G is like EPS bearer in 4G. Each QoS flow is identified by
a QoS flow ID (QFI) which is unique within a PDU session. Each QoS
rule is identified by a QoS rule ID (QRI). There can be more than
one QoS rule associated with the same QoS flow. A default QoS rule
is required to be sent to the UE for every PDU session
establishment and it is associated with a QoS flow.
[0021] In the example of FIG. 1, UE 101 establishes a PDU session
110, which includes multiple QoS flows and QoS rules in Non-Access
Stratum (NAS) layer. Each QoS flow needs to be supported by a
mapping Data Radio Bearer (DRB) in Access Stratum (AS) layer.
Multiple QoS flows can be mapped to the same DRB. For example, QoS
flows #1 and #2 are mapped to DRB #1, and QoS flow #3 is mapped to
DRB #2. If there is a default DRB for a PDU session, then all
traffic of QoS flows that have no mapping DRBs are sent via the
default DRB. However, a PDU session may not always have a default
DRB. In addition, after an intra-system or inter-system handover
procedure, or after a UE-initiated or network-initiated service
request procedure, which triggers the PDU session being
reactivated, the RRC/AS layer may indicate that a QoS flow is not
supported by a mapping DRB, e.g., the mapping DRB for the QoS flow
is not established, or the mapping for the QoS flow to a DRB is
missing and there is no default DRB available.
[0022] In accordance with one novel aspect, a PDU session and QoS
flow handling mechanism is proposed when a QoS flow of a PDU
session does not have a mapping DRB after a handover or a service
request procedure. If the QoS flow is associated with a default QoS
rule, then all QoS flows of the PDU session is impacted and
corresponding action is thus required for the PDU session.
Specifically, the UE can locally release the PDU session, initiate
a PDU session release procedure, send a 5GSM status message with
proper cause, or assume the PDU session is not reactivated. On the
other hand, if the QoS flow is not associated with a default QoS
rule, then only this particular QoS flow is impacted and
corresponding action is thus required for the QoS flow.
Specifically, the UE can locally delete the QoS flow, delete the
QoS flow by using a PDU session modification procedure, or send a
5GSM status message with proper cause.
[0023] FIG. 2 illustrates simplified block diagrams of wireless
devices, e.g., a UE 201 and network entity 211 in accordance with
embodiments of the current invention. Network entity 211 may be a
base station combined with an MME or AMF. Network entity 211 has an
antenna 215, which transmits and receives radio signals. A radio
frequency RF transceiver module 214, coupled with the antenna,
receives RF signals from antenna 215, converts them to baseband
signals and sends them to processor 213. RF transceiver 214 also
converts received baseband signals from processor 213, converts
them to RF signals, and sends out to antenna 215. Processor 213
processes the received baseband signals and invokes different
functional modules to perform features in base station 211. Memory
212 stores program instructions and data 220 to control the
operations of base station 211. In the example of FIG. 2, network
entity 211 also includes protocol stack 280 and a set of control
functional modules and circuit 290. PDU session handling circuit
231 handles PDU session establishment and modification procedures.
QoS flow and rule management circuit 232 creates, modifies, and
deletes QoS flows and QoS rules for UE. Configuration and control
circuit 233 provides different parameters to configure and control
UE of related functionalities including mobility management and
session management.
[0024] Similarly, UE 201 has memory 202, a processor 203, and radio
frequency (RF) transceiver module 204. RF transceiver 204 is
coupled with antenna 205, receives RF signals from antenna 205,
converts them to baseband signals, and sends them to processor 203.
RF transceiver 204 also converts received baseband signals from
processor 203, converts them to RF signals, and sends out to
antenna 205. Processor 203 processes the received baseband signals
and invokes different functional modules and circuits to perform
features in UE 201. Memory 202 stores data and program instructions
210 to be executed by the processor to control the operations of UE
201. Suitable processors include, by way of example, a special
purpose processor, a digital signal processor (DSP), a plurality of
micro-processors, one or more micro-processor associated with a DSP
core, a controller, a microcontroller, application specific
integrated circuits (ASICs), file programmable gate array (FPGA)
circuits, and other type of integrated circuits (ICs), and/or state
machines. A processor in associated with software may be used to
implement and configure features of UE 201.
[0025] UE 201 also comprises a set of functional modules and
control circuits to carry out functional tasks of UE 201. Protocol
stacks 260 comprise Non-Access-Stratum (NAS) layer to communicate
with an AMF entity connecting to the core network, Radio Resource
Control (RRC) layer for high layer configuration and control,
Packet Data Convergence Protocol/Radio Link Control (PDCP/RLC)
layer, Media Access Control (MAC) layer, and Physical (PHY) layer.
System modules and circuits 270 may be implemented and configured
by software, firmware, hardware, and/or combination thereof. The
function modules and circuits, when executed by the processors via
program instructions contained in the memory, interwork with each
other to allow UE 201 to perform embodiments and functional tasks
and features in the network. In one example, system modules and
circuits 270 comprise PDU session handling circuit 221 that
performs PDU session establishment and modification procedures with
the network, a QoS rule management circuit 222 that manages,
creates, modifies, and deletes QoS flows and QoS rules, a config
and control circuit 223 that handles configuration and control
parameters for mobility management and session management.
[0026] FIG. 3 illustrates a first embodiment of PDU session and QoS
flow handling after a handover procedure in accordance with one
novel aspects. In the example of FIG. 3, UE 301 is originally
served by an LTE eNB 304. In step 311, eNB 304 sends a handover
command to the AS layer of UE 301, triggering an inter-system
handover procedure. The target base station is NR gNB 305. The
handover command is embedded with an RRC reconfiguration message,
which provides configuration information for UE to handover to the
target NR cell. From AS layer point of view, the RRC
reconfiguration information element (IE) comprises radio bearer
configuration, which adds DRBs and associated PDU sessions/QoS
flows. For example, a "radioBearerConfig" comprises
"drb-ToAddModList", which comprises "sdap-Config", which further
comprises pdu-Sessoin: indicates PDU session ID; defaultDRB:
indicates whether default DRB is true; mappedQoS-FlowsToAdd:
indicates a sequence of to be mapped QoS flows; and
mappedQoS-FlowsToRelease: indicates a sequence of to be released
QoS flows. Therefore, based on the RRC reconfiguration IE, UE 301
is able to determine which PDU session(s) to be reactivated, and
which QoS flow(s) do not have mapping DRB.
[0027] In step 321, UE 301 camps on the target NR cell. In step
331, UE 301 sends a handover complete to the target base station NR
gNB 305. The handover complete comprises an RRC reconfiguration
complete message. In step 341, the AS layer of UE 301 sends DRB
information forwarding to the NAS layer of UE 301. This is an
internal signaling and the information is mainly based on the
content of the RRC reconfiguration message. In step 351, UE 301
performs PDU session and QoS flow handling after the handover is
completed. In accordance with one novel aspect, UE 301 determines
which PDU session is to be reactivated upon the handover, and
whether each QoS flow of the reactivated PDU session is supported
by a mapping DRB. If there is unsupported QoS flow(s), then UE 301
will further determine whether the QoS flow is associated with a
default QoS rule or not, and perform corresponding action.
[0028] FIG. 4 illustrates a flow chart of a novel PDU session and
QoS flow handling when a QoS flow has no mapping DRB after a PDU
session is reactivated. A UE may have established one or more PDU
sessions with the network, and each PDU session is configured with
one or more QoS flows and one or more QoS rules. One of the QoS
flow is associated with a default QoS rule, which is required for
each PDU session. For the PDU session and QoS handling, the UE
starts with one PDU session (step 411). In step 412, the UE
determines whether the PDU session is reactivated, e.g., due to an
RRC reconfiguration. If yes, then the UE goes to step 413 and
determines whether a selected QoS flow is supported by a mapping
DRB. If yes, then the UE goes to step 414 and checks whether the
PDU session has more QoS flows. If there are more QoS flows, then
the UE goes back to step 413 and select another QoS flow to check.
If the answer to step 413 is no, then the UE goes to step 415 and
checks whether the QoS flow is associated with a default QoS
rule.
[0029] If the QoS flow is associated with the default QoS rule,
then the entire PDU session is impacted. As a result, the UE needs
to handle the PDU session accordingly. In a first option (step
421), the UE release the PDU session implicitly or explicitly. If
implicitly, the UE releases the PDU session locally, and optionally
initiate a registration procedure for synchronization with the
network. If explicitly, the UE initiates a PDU session release
procedure to release the PDU session. In a second option (422), the
UE sends 5GSM status message with proper cause to inform the
network. In a third option (423), the UE assumes the PDU session is
not reactivated, and optionally initiates a registration procedure
with the network for synchronization.
[0030] If the QoS flow is not associated with the default QoS rule,
then only the QoS flow is impacted. As a result, the UE needs to
handle the QoS flow accordingly. In a first option (431), the UE
deletes the QoS flow implicitly or explicitly. If implicitly, the
UE deletes the QoS flow locally, and optionally sends a PDU session
modification to the network. If explicitly, the UE deletes the QoS
flow by using a PDU session modification procedure. In a second
option (432), the UE sends 5GSM status message with proper cause to
inform the network. In a third option (433), the UE assumes the QoS
flow is not reactivated, and optionally initiates a registration
procedure with the network for synchronization.
[0031] FIG. 5 illustrates a second embodiment of PDU session and
QoS flow handling after a UE-initiated service request procedure in
accordance with one novel aspects. In the example of FIG. 5, UE 501
is originally in RRC idle mode or in RRC connected mode. In step
311, UE 501 has uplink data pending over a PDU session, which is
inactive. If UE is in idle mode, then UE needs to go to connected
mode and reactivate the PDU session via a service request; if UE is
in connected mode, then UE also needs to reactivate the PDU session
via a service request. In step 521, UE 501 sends a service request
from NAS layer to the network to reactivate the PDU session.
[0032] In step 531, the target RAN 505 sends an RRC reconfiguration
message to the AS layer of UE 501 in response to the service
request. From AS layer point of view, the RRC reconfiguration
message comprises radio bearer configuration, which adds DRBs and
associated PDU sessions/QoS flows. Note that the RAN may send
multiple RRC reconfiguration messages subsequently, e.g., another
RRC reconfiguration message in step 532. Each RRC reconfiguration
message may provide additional radio bearer configuration for UE
501. As a result, UE 501 may need to wait for some time in order to
receive all the RRC reconfiguration messages. In step 541, the AS
layer of UE 501 sends DRB information forwarding to the NAS layer
of UE 501. This is an internal signaling and the information is
mainly based on the content of the RRC reconfiguration message(s).
In step 551, UE 501 performs PDU session and QoS flow handling
after the handover is completed. In accordance with one novel
aspect, UE 501 determines which PDU session is to be reactivated
upon the handover, and whether each QoS flow of the reactivated PDU
session is supported by a mapping DRB. If there is unsupported QoS
flow(s), then UE 501 will further determine whether the QoS flow is
associated with a default QoS rule or not, and perform
corresponding actions.
[0033] FIG. 6 illustrates a third embodiment of PDU session and QoS
flow handling after a network-initiated service request procedure
in accordance with one novel aspects. In the example of FIG. 6, UE
601 is in RRC idle mode (step 611). In step 621, network 610 has
downlink data pending for UE 601. In step 631, network 610 sends a
paging message to the AS layer of UE 601 via RAN 605. In step 641,
the AS layer sends paging parameter forwarding to the NAS layer of
UE 601. Upon receiving the paging, UE 601 knows that it needs to go
to RRC connected mode via a service request. In step 651, UE 601
sends a service request from NAS layer to the network to reactivate
the PDU session. In step 661, the target RAN 505 sends an RRC
reconfiguration message to the AS layer of UE 501 in response to
the service request. From AS layer point of view, the RRC
reconfiguration message comprises radio bearer configuration, which
adds DRBs and associated PDU sessions/QoS flows. Note that the RAN
may send multiple RRC reconfiguration messages subsequently, e.g.,
another RRC reconfiguration message in step 662. Each RRC
reconfiguration message may provide additional radio bearer
configuration for UE 601. In step 671, the AS layer of UE 601 sends
DRB information forwarding to the NAS layer of UE 601. This is an
internal signaling and the information is mainly based on the
content of the RRC reconfiguration message(s). In step 681, UE 601
performs PDU session and QoS flow handling after the handover is
completed. In accordance with one novel aspect, UE 601 determines
which PDU session is to be reactivated upon the handover, and
whether each QoS flow of the reactivated PDU session is supported
by a mapping DRB. If there is unsupported QoS flow(s), then UE 601
will further determine whether the QoS flow is associated with a
default QoS rule or not, and perform corresponding action.
[0034] FIG. 7 is a flow chart of a method of PDU session and QoS
flow handling in accordance with one novel aspect of the present
invention. In step 701, a UE receives a radio resource control
(RRC) reconfiguration in a mobile communication network. The UE is
configured with one or more Protocol data unit (PDU) sessions, and
an activated PDU session is configured with one or more QoS flows.
In step 702, the UE detects that a QoS flow of the activated PDU
session has no mapping data radio bearer (DRB) available based on
the RRC reconfiguration. In step 703, the UE performs a first PDU
session and QoS flow handling when the QoS flow is associated with
a default QoS rule. In step 704, the UE performs a second PDU
session and QoS flow handing when the QoS flow is not associated
with the default QoS rule.
[0035] Although the present invention has been described in
connection with certain specific embodiments for instructional
purposes, the present invention is not limited thereto.
Accordingly, various modifications, adaptations, and combinations
of various features of the described embodiments can be practiced
without departing from the scope of the invention as set forth in
the claims.
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