U.S. patent application number 13/808471 was filed with the patent office on 2013-05-02 for method for user equipment transmitting service preference information in wireless communication system and apparatus for same.
This patent application is currently assigned to LG ELECTRONICS INC.. The applicant listed for this patent is Sungduck Chun, Sunghoon Jung, Youngdae Lee, Sungjun Park, Seungjune Yi. Invention is credited to Sungduck Chun, Sunghoon Jung, Youngdae Lee, Sungjun Park, Seungjune Yi.
Application Number | 20130107790 13/808471 |
Document ID | / |
Family ID | 46969654 |
Filed Date | 2013-05-02 |
United States Patent
Application |
20130107790 |
Kind Code |
A1 |
Lee; Youngdae ; et
al. |
May 2, 2013 |
METHOD FOR USER EQUIPMENT TRANSMITTING SERVICE PREFERENCE
INFORMATION IN WIRELESS COMMUNICATION SYSTEM AND APPARATUS FOR
SAME
Abstract
The present invention relates to a method for a user equipment
to transmit/receive a signal in a wireless communication system,
and more specifically, comprises the following steps: setting a
priority between a multimedia broadcast multicast service (MBMS)
and a unicast service; transmitting the priority which is set to a
network; transmitting a measurement report on a target node to the
network; and receiving from the network a handover command which is
determined based on the priority and the measurement report.
Inventors: |
Lee; Youngdae; (Anyang-si,
KR) ; Yi; Seungjune; (Anyang-si, KR) ; Chun;
Sungduck; (Anyang-si, KR) ; Park; Sungjun;
(Anyang-si, KR) ; Jung; Sunghoon; (Anyang-si,
KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Lee; Youngdae
Yi; Seungjune
Chun; Sungduck
Park; Sungjun
Jung; Sunghoon |
Anyang-si
Anyang-si
Anyang-si
Anyang-si
Anyang-si |
|
KR
KR
KR
KR
KR |
|
|
Assignee: |
LG ELECTRONICS INC.
Seoul
KR
|
Family ID: |
46969654 |
Appl. No.: |
13/808471 |
Filed: |
April 5, 2012 |
PCT Filed: |
April 5, 2012 |
PCT NO: |
PCT/KR12/02560 |
371 Date: |
January 4, 2013 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
61473157 |
Apr 8, 2011 |
|
|
|
Current U.S.
Class: |
370/312 |
Current CPC
Class: |
H04W 72/1247 20130101;
H04W 36/24 20130101; H04W 36/0088 20130101; H04W 76/40 20180201;
H04W 4/06 20130101; H04W 36/0007 20180801; H04W 8/20 20130101 |
Class at
Publication: |
370/312 |
International
Class: |
H04H 20/57 20080101
H04H020/57 |
Claims
1-12. (canceled)
13. A method of communicating with a network at a user equipment in
a wireless communication system, the method comprising:
prioritizing a multimedia broadcast multicast service (MBMS)
service reception above a non-MBMS service reception; and
transmitting an indication indicating that the MBMS reception is
prioritized above the non-MBMS service reception to the
network.
14. The method of claim 13, wherein the indication is transmitted
with information on the MBMS service preferred by the user
equipment.
15. The method of claim 13, wherein the non-MBMS service is a
unicast service.
16. The method of claim 13, further comprising: receiving system
information including information on the MBMS service.
17. The method of claim 14, further comprising: receiving the MBMS
service preferred by the user equipment from the network.
18. The method of claim 13, wherein the indication is transmitted
using a radio resource control (RRC) message.
19. A method of communicating with a user equipment at a network in
a wireless communication system, the method comprising:
transmitting system information including information on a
multimedia broadcast multicast service (MBMS) service to the user
equipment; and receiving an indication indicating that the MBMS
service reception is prioritized above a non-MBMS service reception
from the user equipment.
20. The method of claim 19, wherein the indication is received with
information on the MBMS service preferred by the user
equipment.
21. The method of claim 19, wherein the non-MBMS service is a
unicast service.
22. The method of claim 20, further comprising: transmitting, to
the user equipment, the MBMS service preferred by the user
equipment.
23. The method of claim 19, wherein the indication is received
using a radio resource control (RRC) message.
Description
TECHNICAL FIELD
[0001] The present invention relates to a wireless communication
system, and more particularly, to a method and apparatus for
transmitting service preference information from a user equipment
(UE) in a wireless communication system.
BACKGROUND ART
[0002] As an example of a wireless communication system to which
the present invention is applicable, a 3.sup.rd generation
partnership project (3GPP) long term evolution (LTE) communication
system will be schematically described.
[0003] FIG. 1 is a schematic diagram showing a network structure of
an evolved universal mobile telecommunications system (E-UMTS) as
an example of a wireless communication system. The E-UMTS is an
evolved form of the legacy UMTS and has been standardized in the
3GPP. In general, the E-UMTS is also called an LTE system. For
details of the technical specification of the UMTS and the E-UMTS,
refer to Release 7 and Release 8 of "3.sup.rd Generation
Partnership Project; Technical Specification Group Radio Access
Network".
[0004] Referring to FIG. 1, the E-UMTS includes a user equipment
(UE), an evolved node B (eNode B or eNB), and an access gateway
(AG) which is located at an end of an evolved UMTS terrestrial
radio access network (E-UTRAN) and connected to an external
network. The eNB may simultaneously transmit multiple data streams
for a broadcast service, a multicast service and/or a unicast
service.
[0005] One or more cells may exist per eNB. The cell is set to
operate in one of bandwidths such as 1.25, 2.5, 5, 10, 15, and 20
MHz and provides a downlink (DL) or uplink (UL) transmission
service to a plurality of UEs in the bandwidth. Different cells may
be set to provide different bandwidths. The eNB controls data
transmission or reception to and from a plurality of UEs. The eNB
transmits DL scheduling information of DL data to a corresponding
UE so as to inform the UE of a time/frequency domain in which the
DL data is supposed to be transmitted, coding, a data size, and
hybrid automatic repeat and request (HARQ)-related information. In
addition, the eNB transmits UL scheduling information of UL data to
a corresponding UE so as to inform the UE of a time/frequency
domain which may be used by the UE, coding, a data size, and
HARQ-related information. An interface for transmitting user
traffic or control traffic may be used between eNBs. A core network
(CN) may include the AG and a network node or the like for user
registration of UEs. The AG manages the mobility of a UE on a
tracking area (TA) basis. One TA includes a plurality of cells.
[0006] Although wireless communication technology has been
developed to LTE based on wideband code division multiple access
(WCDMA), the demands and expectations of users and service
providers are on the rise. In addition, considering other radio
access technologies under development, new technological evolution
is required to secure high competitiveness in the future. Decrease
in cost per bit, increase in service availability, flexible use of
frequency bands, a simplified structure, an open interface,
appropriate power consumption of UEs, and the like are
required.
DISCLOSURE
Technical Problem
[0007] An object of the present invention devised to solve the
problem lies in a method of and apparatus for transmitting service
preference information from a user equipment (UE) in a wireless
communication system.
Technical Solution
[0008] The object of the present invention can be achieved by
providing a method for transmitting and receiving a signal at a
user equipment (UE) in a wireless communication system, the method
including setting a priority between a multimedia broadcast
multicast service (MBMS) and a unicast service, transmitting the
priority to a network, transmitting a measurement report on a
target node to the network, and receiving a handover command
determined based on the priority and the measurement report from
the network.
[0009] In another aspect of the present invention, provided herein
is a method for transmitting and receiving a signal between a
network and a user equipment (UE) in a wireless communication
system, the method including receiving a priority between a
multimedia broadcast multicast service (MBMS) and a unicast
service, receiving a measurement report on a target node from the
UE, determining whether handover to the target node is performed
based on the priority and the measurement report, and transmitting
a handover command to the target node to the UE. Preferably, the
method may further include transmitting a handover request message
to the target node, and receiving a handover request response
message from the target node, wherein the handover request message
includes the priority.
[0010] The measurement report may include information indicating
whether the UE currently receives the MBMS provided at a frequency
of the target node or the UE is interested in reception of the MBMS
provided at the frequency of the target node. In addition, the
priority may be included in a handover request message transmitted
from a serving node to the target node. Furthermore, the priority
may correspond to user preference.
[0011] More preferably, the serving node may be a serving cell and
the target node may be a target cell.
[0012] The unicast service may include at least one of a closed
subscriber group (CSG) service, a voice service, a UE dedicated
service, and a virtual private network (VPN) service.
Advantageous Effects
[0013] According to the embodiments of the present invention, a
network may effectively provide a multimedia broadcast multicast
service (MBMS) to a user equipment (UE). In detail, the UE may
transmit service preference information to the network such that
the network may handover the UE to a cell that can provide the
MBMS, and thus, the UE may effectively receive a preferred
service.
[0014] The effects of the present invention are not limited to the
above-described effects and other effects which are not described
herein will become apparent to those skilled in the art from the
following description.
DESCRIPTION OF DRAWINGS
[0015] FIG. 1 is a diagram showing a network structure of an
Evolved Universal Mobile Telecommunications System (E-UMTS) as an
example of a wireless communication system.
[0016] FIG. 2 is a diagram conceptually showing a network structure
of an evolved universal terrestrial radio access network
(E-UTRAN).
[0017] FIG. 3 is a diagram showing a control plane and a user plane
of a radio interface protocol between a UE and an E-UTRAN based on
a 3.sup.rd generation partnership project (3GPP) radio access
network standard.
[0018] FIG. 4 is a diagram showing physical channels used in a 3GPP
system and a general signal transmission method using the same.
[0019] FIG. 5 is a diagram showing the structure of a radio frame
used in a Long Term Evolution (LTE) system.
[0020] FIG. 6 is a diagram showing a general transmission and
reception method using a paging message.
[0021] FIG. 7 is a diagram showing a transmission method of
multimedia broadcast multicast service control channel (MCCH)
information.
[0022] FIG. 8 is a diagram of a wireless communication system
including a home eNB (HeNB).
[0023] FIG. 9 is a diagram of a handover process based on service
preference, according to an embodiment of the present
invention.
[0024] FIG. 10 is a block diagram of a communication apparatus
according to an embodiment of the present invention.
BEST MODE
[0025] The configuration, operation and other features of the
present invention will be understood by the embodiments of the
present invention described with reference to the accompanying
drawings. The following embodiments are examples of applying the
technical features of the present invention to a 3rd generation
partnership project (3GPP) system.
[0026] Although the embodiments of the present invention are
described using a long term evolution (LTE) system and a
LTE-advanced (LTE-A) system in the present specification, they are
purely exemplary. Therefore, the embodiments of the present
invention are applicable to any other communication system
corresponding to the above definition. In addition, although the
embodiments of the present invention are described based on a
frequency division duplex (FDD) scheme in the present
specification, the embodiments of the present invention may be
easily modified and applied to a half-duplex FDD (H-FDD) scheme or
a time division duplex (TDD) scheme.
[0027] FIG. 2 is a diagram conceptually showing a network structure
of an evolved universal terrestrial radio access network (E-UTRAN).
An E-UTRAN system is an evolved form of a legacy UTRAN system. The
E-UTRAN includes cells (eNB) which are connected to each other via
an X2 interface. A cell is connected to a user equipment (UE) via a
radio interface and to an evolved packet core (EPC) via an S1
interface.
[0028] The EPC includes a mobility management entity (MME), a
serving-gateway (S-GW), and a packet data network-gateway (PDN-GW).
The MME has information about connections and capabilities of UEs,
mainly for use in managing the mobility of the UEs. The S-GW is a
gateway having the E-UTRAN as an end point, and the PDN-GW is a
gateway having a packet data network (PDN) as an end point.
[0029] FIG. 3 is a diagram showing a control plane and a user plane
of a radio interface protocol between a UE and an E-UTRAN based on
a 3GPP radio access network standard. The control plane refers to a
path used for transmitting control messages used for managing a
call between the UE and the E-UTRAN. The user plane refers to a
path used for transmitting data generated in an application layer,
e.g., voice data or Internet packet data.
[0030] A physical (PHY) layer of a first layer provides an
information transfer service to a higher layer using a physical
channel. The PHY layer is connected to a medium access control
(MAC) layer located on the higher layer via a transport channel.
Data is transported between the MAC layer and the PHY layer via the
transport channel. Data is transported between a physical layer of
a transmitting side and a physical layer of a receiving side via
physical channels. The physical channels use time and frequency as
radio resources. In detail, the physical channel is modulated using
an orthogonal frequency division multiple access (OFDMA) scheme in
downlink and is modulated using a single carrier frequency division
multiple access (SC-FDMA) scheme in uplink.
[0031] The MAC layer of a second layer provides a service to a
radio link control (RLC) layer of a higher layer via a logical
channel. The RLC layer of the second layer supports reliable data
transmission. A function of the RLC layer may be implemented by a
functional block of the MAC layer. A packet data convergence
protocol (PDCP) layer of the second layer performs a header
compression function to reduce unnecessary control information for
efficient transmission of an Internet protocol (IP) packet such as
an IP version 4 (IPv4) packet or an IP version 6 (IPv6) packet in a
radio interface having a relatively small bandwidth.
[0032] A radio resource control (RRC) layer located at the bottom
of a third layer is defined only in the control plane. The RRC
layer controls logical channels, transport channels, and physical
channels in relation to configuration, re-configuration, and
release of radio bearers (RBs). An RB refers to a service that the
second layer provides for data transmission between the UE and the
E-UTRAN. To this end, the RRC layer of the UE and the RRC layer of
the E-UTRAN exchange RRC messages with each other.
[0033] One cell of the eNB is set to operate in one of bandwidths
such as 1.25, 2.5, 5, 10, 15, and 20 MHz and provides a downlink or
uplink transmission service to a plurality of UEs in the bandwidth.
Different cells may be set to provide different bandwidths.
[0034] Downlink transport channels for transmission of data from
the E-UTRAN to the UE include a broadcast channel (BCH) for
transmission of system information, a paging channel (PCH) for
transmission of paging messages, and a downlink shared channel
(SCH) for transmission of user traffic or control messages. Traffic
or control messages of a downlink multicast or broadcast service
may be transmitted through the downlink SCH and may also be
transmitted through a separate downlink multicast channel
(MCH).
[0035] Uplink transport channels for transmission of data from the
UE to the E-UTRAN include a random access channel (RACH) for
transmission of initial control messages and an uplink SCH for
transmission of user traffic or control messages. Logical channels
that are defined above the transport channels and mapped to the
transport channels include a broadcast control channel (BCCH), a
paging control channel (PCCH), a common control channel (CCCH), a
multicast control channel (MCCH), and a multicast traffic channel
(MTCH).
[0036] FIG. 4 is a diagram showing physical channels used in a 3GPP
system and a general signal transmission method using the same.
[0037] When a UE is powered on or enters a new cell, the UE
performs an initial cell search operation such as synchronization
with an eNB (S401). To this end, the UE may receive a primary
synchronization channel (P-SCH) and a secondary synchronization
channel (S-SCH) from the eNB to perform synchronization with the
eNB and acquire information such as a cell ID. Then, the UE may
receive a physical broadcast channel from the eNB to acquire
broadcast information in the cell. During the initial cell search
operation, the UE may receive a downlink reference signal (DL RS)
so as to confirm a downlink channel state.
[0038] After the initial cell search operation, the UE may receive
a physical downlink control channel (PDCCH) and a physical downlink
control channel (PDSCH) based on information included in the PDCCH
to acquire more detailed system information (S402).
[0039] When the UE initially accesses the eNB or has no radio
resources for signal transmission, the UE may perform a random
access procedure (RACH) with respect to the eNB (steps S403 to
S406). To this end, the UE may transmit a specific sequence as a
preamble through a physical random access channel (PRACH) (S403)
and receive a response message to the preamble through the PDCCH
and the PDSCH corresponding thereto (S404). In the case of
contention-based RACH, the UE may further perform a contention
resolution procedure.
[0040] After the above procedure, the UE may receive PDCCH/PDSCH
from the eNB (S407) and may transmit a physical uplink shared
channel (PUSCH)/physical uplink control channel (PUCCH) to the eNB
(S408), which is a general uplink/downlink signal transmission
procedure. Particularly, the UE receives downlink control
information (DCI) through the PDCCH. Here, the DCI includes control
information such as resource allocation information for the UE.
Different DCI formats are defined according to different usages of
DCI.
[0041] Control information transmitted from the UE to the eNB in
uplink or transmitted from the eNB to the UE in downlink includes a
downlink/uplink acknowledge/negative acknowledge (ACK/NACK) signal,
a channel quality indicator (CQI), a precoding matrix index (PMI),
a rank indicator (RI), and the like. In the case of the 3GPP LTE
system, the UE may transmit the control information such as
CQI/PMI/RI through the PUSCH and/or the PUCCH.
[0042] FIG. 5 is a diagram showing the structure of a radio frame
used in an LTE system.
[0043] Referring to FIG. 5, the radio frame has a length of 10 ms
(327200.times.Ts) and is divided into 10 subframes having the same
size. Each of the subframes has a length of 1 ms and includes two
slots. Each of the slots has a length of 0.5 ms (15360.times.Ts).
Ts denotes a sampling time, and is represented by Ts=1/(15
kHz.times.2048)=3.2552.times.10.sup.-8 (about 33 ns). Each of the
slots includes a plurality of OFDM symbols in a time domain and a
plurality of Resource Blocks (RBs) in a frequency domain. In the
LTE system, one RB includes 12 subcarriers.times.7 (or 6) OFDM
symbols. A transmission time interval (TTI) that is a unit time for
transmission of data may be determined in units of one or more
subframes. The structure of the radio frame is purely exemplary and
thus the number of subframes included in the radio frame, the
number of slots included in a subframe, or the number of OFDM
symbols included in a slot may be changed in various ways.
[0044] Hereinafter, an RRC state of a UE and an RRC connection
method will be described.
[0045] The RRC state indicates whether the RRC layer of the UE is
logically connected to the RRC layer of the E-UTRAN. When the RRC
connection is established, the UE is in a RRC_CONNECTED state.
Otherwise, the UE is in a RRC_IDLE state.
[0046] The E-UTRAN can effectively control UEs because it can check
the presence of RRC_CONNECTED UEs on a cell basis. On the other
hand, the E-UTRAN cannot check the presence of RRC_IDLE UEs on a
cell basis and thus a CN manages RRC_IDLE UEs on a TA basis. A TA
is an area unit larger than a cell. That is, in order to receive a
service such as a voice service or a data service from a cell, the
UE needs to transition to the RRC_CONNECTED state.
[0047] In particular, when a user initially turns a UE on, the UE
first searches for an appropriate cell and camps on the cell in the
RRC_IDLE state. The RRC_IDLE UE transitions to the RRC_CONNECTED
state by performing an RRC connection establishment procedure only
when the RRC_IDLE UE needs to establish an RRC connection. For
example, when uplink data transmission is necessary due to call
connection attempt of a user or when a response message is
transmitted in response to a paging message received from the
E-UTRAN, the RRC_IDLE UE needs to be RRC connected to the
E-UTRAN.
[0048] FIG. 6 is a diagram showing a general transmission and
reception method using a paging message.
[0049] Referring to FIG. 6, the paging message includes a paging
record having paging cause and UE identity. Upon receiving the
paging message, the UE may perform a discontinuous reception (DRX)
operation in order to reduce power consumption.
[0050] In detail, a network configures a plurality of paging
occasions (POs) in every time cycle called a paging DRC cycle and a
specific UE receives only a specific paging occasion and acquires a
paging message. The UE does not receive a paging channel in paging
occasions other than the specific paging occasion and may be in a
sleep state in order to reduce power consumption. One paging
occasion corresponds to one TTI.
[0051] The eNB and the UE use a paging indicator (PI) as a specific
value indicating transmission of a paging message. The eNB may
define a specific identity (e.g., paging-radio network temporary
identity (P-RNTI)) as the PI and inform the UE of paging
information transmission. For example, the UE wakes up in every DRX
cycle and receives a subframe to determine the presence of a paging
message directed thereto. In the presence of the P-RNTI on an L1/L2
control channel (a PDCCH) in the received subframe, the UE is aware
that a paging message exists on a PDSCH of the subframe. When the
paging message includes an ID of the UE (e.g., an international
mobile subscriber identity (IMSI)), the UE receives a service by
responding to the eNB (e.g., establishing an RRC connection or
receiving system information).
[0052] System information will now be described. The system
information includes essential information necessary to connect a
UE to an eNB. Accordingly, the UE should receive all system
information before being connected to the eNB and should always
have new system information. The eNB periodically transmits the
system information because all UEs located in a cell should know
the system information.
[0053] The system information may be divided into a master
information block (MIB), a scheduling block (SB), and a system
information block (SIB). The MIB enables a UE to become aware of a
physical configuration of a cell, for example, a bandwidth. The SB
indicates transmission information of SIBs, for example, a
transmission period. The SIB is a set of associated system
information. For example, a specific SIB includes only information
about peripheral cells and another SIB includes only information
about an uplink radio channel used by a UE.
[0054] Hereinafter, a cell selection and cell reselection process
will be described.
[0055] When a UE is powered on, the UE needs to select a cell
having appropriate quality and to perform preparation procedures
for receiving a service. An RRC_IDLE UE should always select
appropriate quality and prepare to receive a service from the cell.
For example, a UE which has just been turned on should select a
cell having appropriate quality in order to perform registration
with a network. When an RRC_CONNECTED UE enters an RRC_IDLE state,
the UE should select a cell on which the UE will camp in the
RRC_IDLE state. A process of, at a UE, selecting a cell satisfying
a specific condition in order to camp on the cell in a service
standby state such as an RRC_IDLE state is referred to as cell
selection. Since the cell selection is performed in a state in
which the UE does not determine a cell on which the UE camps in the
RRC_IDLE state, it is important to select a cell as fast as
possible. Accordingly, a cell which provides radio signal quality
equal to or greater than a predetermined reference may be selected
in the cell selection process of the UE, even if the cell does not
provide the best radio signal quality to the UE.
[0056] When the UE selects a cell satisfying a cell selection
reference, the UE receives information necessary for an operation
of the RRC_IDLE UE in the cell from the system information of the
cell. The UE receives all information necessary for the operation
of the RRC_IDLE UE and then requests a service from a network or
awaits reception of a service from the network in a RRC_IDLE
state.
[0057] After the UE selects a certain cell in the cell selection
process, the intensity or quality of a signal between the UE and
the eNB may be changed due to mobility of the UE or wireless
environment change. Accordingly, when the quality of the selected
cell deteriorates, the UE may select another cell which provides
better quality. When the cell is reselected, a cell which provides
better signal quality than a currently selected cell is generally
selected. Such a process is referred to as cell reselection. The
cell reselection process is performed in order to select a cell
which provides the best quality to the UE from the viewpoint of the
quality of the radio signal. In addition to the quality of the
radio signal, the network may set a priority per frequency and
inform the UE of the priority. The UE which receives the priority
preferentially takes the priority into consideration, rather than
the radio signal quality.
[0058] Hereinafter, a multimedia broadcast multicast service (MBMS)
will be described. The MBMS refers to a kind of broadcast/multicast
service and simultaneously transmits multimedia data packets to a
plurality of UEs. The terms `broadcast/multicast service` and
`MBMS` used in the present specification may be replaced with terms
`point-to-multipoint service` and `multicast and broadcast service
(MBS)`. With regard to the MBMS based on IP multicast, UEs shares
resources necessary for data packet transmission with each other to
receive the same multimedia data. Accordingly, when UEs satisfying
a predetermined reference, which use the MBMS, exist in the same
cell, resource efficiency may be increased. The MBMS is not
associated with a RRC connection state and thus the RRC_IDLE UE may
also receive the MBMS.
[0059] A logical channel for the MBMS, that is, a MBMS control
Channel (MCCH) or a MEMS traffic channel (MTCH) may be mapped to a
transport channel, that is, an MBMS channel (MCH). The MCCH
transmits an RRC message including MBMS-related common control
information and the MTCH transmits traffic of a specific MBMS. When
one MCCH may exist in every MBMS Single Frequency Network (MBSFN)
area that transmits the same MBMS information or traffic and a
plurality of MBSFN areas are provided by one cell, the UE may
receive a plurality of MCCHs. FIG. 7 is a diagram showing a
transmission method of MCCH information.
[0060] Referring to FIG. 7, when a MBMS-related RRC message is
changed in a predetermined MCCH, a PDCCH transmits a MBMS-radio
network temporary identity (M-RNTI) and an MCCH indicator
indicating the MCCH. A UE supporting the MBMS may receive the
M-RNTI and the MCCH indicator through the PDCCH, check that the
MBMS-related RRC message is changed in the MCCH, and receive the
MCCH. The MBMS-related RRC message may be changed in every change
cycle and may be repeatedly broadcast in every repeat cycle. FIG. 7
is a diagram showing the transmission method of the MCCH
information.
[0061] The MCCH transmits an MBSFNAreaConfiguration message
indicating setting between a current MBMS session and an RB
corresponding thereto. The MCCH may receive one or more MBMSs or
may transmit an MBMSCountingRequest message for counting of the
number of RRC_CONNECTED UEs.
[0062] In addition, specific MBMS control information may be
provided through a BCCH. In particular, the MBMS control
information may be included in SystemInformationBlockType13
broadcast through the BCCH.
[0063] Hereinafter, a home eNB (HeNB) (or HNB) will be described. A
mobile communication service may be provided through an eNB owned
by an individual or a specific service provider as well as an eNB
of a mobile network operator. Such an eNB is referred to as an HNB
or HeNB. An object of the HeNB is to basically provide a
specialized service of a closed subscriber group (CSG). However,
the HeNB may provide services to other subscribers in addition to
the CSG according to operational mode settings of the HeNB.
[0064] FIG. 8 is a diagram of a wireless communication system
including a HeNB.
[0065] Referring to FIG. 8, an E-UTRAN may operate a HeNB gateway
(HeNB GW) in order to provide a service of the HeNB. HeNBs may be
connected to an EPC through the HeNB GW or may be connected
directly to the EPC. The HeNB GW is recognized as a general cell by
an MME and is recognized as the MME by the HeNB. Accordingly, the
HeNB and the HeNB GW are connected to each other through an S1
interface and the HeNB GW and the EPC are also connected to each
other through the S1 interface. In addition, when the HeNB and the
EPC are connected directly to each other, the S1 interface may also
be used.
[0066] In general, the HeNB has higher radio transmission output
power compared with an eNB of a mobile network operator.
Accordingly, generally, a service coverage provided by the HeNB is
smaller than a service coverage provided by the eNB. Due to this
property, from the viewpoint of the service coverage, a cell
provided by the HeNB is frequently categorized into a femto cell
compared with a macrocell provided by the eNB. From the viewpoint
of a provided service, when the HeNB provides a service to a CSG
only, the cell provided by the HeNB is referred to as a CSG
cell.
[0067] Conventionally, when a UE tries to receive the MBMS, a
problem that the UE cannot properly receive the MBMS may arise for
the following reasons. 1) When the UE moves to a CSG cell, the UE
cannot receive the MBMS from the CSG cell because the CSG cell does
not support the MBMS due to its property. 2) The UE cannot
simultaneously receive the MBMS and other services according to the
capabilities of the UE.
[0068] Thus, according to the present invention, in order to
overcome the problem that the UE cannot receive the MBMS, the UE
prioritizes user preferences of the MBMS and other services and
transmits indicators of the user preferences through a wireless
network. Here, the services excluding the MBMS may be a unicast
service and may include a voice service, a UE dedicated service, or
a virtual private network (VPN) service. The VPN service refers to
a service system that directly controls and monitors a
communication network in companies.
[0069] The user preferences may refer to preferences of the MBMS
and a CSG service (or local IP access (LIPA) service). For example,
when the preference of the CSG service (or LIPA service) is higher
than the preference of the MBMS, the E_UTRAN may move, that is,
handover the UE to the CSG cell (or LIPA cell). In addition, when
the preference of the CSG service (or LIPA service) is lower than
the preference of the MBMS, that is, when the reference of the MBMS
is relatively high, the E_UTRAN may handover the UE to a cell
providing the MBMS, instead of moving the UE to the CSG cell (or
LIPA cell).
[0070] FIG. 9 is a diagram of a handover process based on service
preference, according to an embodiment of the present
invention.
[0071] Referring to FIG. 9, first, a UE determines service
preference. For example, the UE may prefer a CSG service to an MBMS
or prefer the CSG service to the MBMS. The UE may prefer a first
MBMS (service) to a second MBMS (service) or prefer a first MBSFN
area to a second MBSFN area. In addition, the UE may prefer the
MBMS to a UE dedicated service or prefer the UE dedicated service
to the MBMS. After the determination of the service preference, the
UE transmits service preference information to a CN (or a radio
access network (RAN)) in step 901. Preferably, the UE may transmit
information about preferred service(s) and preferred MBSFN area(s),
that is, MBMS ID(s) or MBSFN area ID(s) in addition to the service
preference information of the UE to the CN.
[0072] Then, the CN that receives the service preference
information transmits the service preference information to a cell
connected to the UE, that is, a serving cell, in step 902. The
service preference information may be sequentially transmitted to
the UE, the CN, and the serving cell in the order stated through a
NAS layer. However, alternatively, the service preference may be
transmitted from the UE directly to the serving cell via RRC
signaling.
[0073] After measurement of one or more target cells, when quality
of a measured target cell is equal to or greater than a preset
threshold value, the UE may inform the serving cell of information
about the quality of the target cell in step 903. That is, the UE
may inform the serving cell of a measurement report message. In
this case, the UE may transmit the measurement report message that
contains the target cell quality information together with
information about a MBMS reception state. The measurement report
message is reported to the serving cell that is a source cell.
Here, the MBMS reception state information may indicate whether the
UE currently receives the MBMS provided at a frequency of the
target cell or the UE is interested in reception of the MBMS
provided at the frequency of the target cell.
[0074] Then, the source cell may determine handover according to
the service preference in addition to the target cell quality
information in step 904. For example, when the UE prefers the MBMS
to the CSG service, the source cell determines handover to a
non-CSG cell instead of a CSG cell. When the UE prefers the CSG
service to the MBMS, the source cell determines handover to the CSG
cell instead of the non-CSG cell. When the UE moves to the CSG
cell, the UE may stop receiving the MBMS.
[0075] When the UE receives or wants to receive the first MBMS and
the second MBMS, if the first MBMS and the second MBMS are provided
at different frequencies, the source cell determines a cell having
a frequency at which the preferred MBMS is provided as the target
cell and determines handover to the target cell.
[0076] In FIG. 9, for convenience of description, it is assumed
that the service preference indicates that the UE prefers the MBMS
to the CSG service and the source cell determines the non-CSG cell
as the target cell according to the service preference and
determines handover to the target cell.
[0077] Thus, the source cell transmits a handover request message
to the target cell in step 905. The handover request message may
include the MBMS reception state information received from the UE.
That is, when the UE is interested in the MBMS or receives the
MBMS, the MBMS reception state information may include a frequency
at which the MBMS is provided, or an ID of MBSFN area or MBMS
providing the MBMS. Alternatively, the MBMS reception state
information may be contained in a handover completion message that
will be described below and then the UE may transmit the handover
completion message directly to the target cell.
[0078] When the target cell is ready to provide the MBMS, the
target cell transmits a handover request ACK message to the source
cell in step 906, and the source cell transmits a handover command
message to the UE in step 907.
[0079] The UE that receives the handover command message from the
source cell may receive an MBMS notification transmitted from the
target cell using information included in the handover command
message in step 908. In detail, the UE may blind decode a PDCCH
masked with an M-RNTI to acquire the MBMS notification. Here, the
MBMS notification refers to information to indicate session start
to the UE and to transmit corresponding resource information and
the session start indicates that data transmission of a
corresponding service is prepared.
[0080] The UE that acquires the MBMS notification transmits the
handover completion message in step 909. In addition to a process
of, at the source cell, transmitting the handover request message
containing the MBMS reception state information to the target cell,
the MBMS reception state information may be contained in the
handover completion message and then the UE may transmit the
handover completion message directly to the target cell, as
described above.
[0081] Lastly, when the MBMS notification indicates information
change in the MBSFN area providing the MBMS, the UE receives a MCCH
of the MBSFN area to acquire the changed information in step 910.
When the MCCH indicates the session start of the MBMS, the UE sets
a MTCH of the MBMS and receives MBMS data in step 911.
[0082] As described above, according to the present invention, the
UE may determine the service preferences of the MBMS and other
services and may transmit the indicators indicating the service
preferences to the CN so as to smoothly receive the MBMS.
[0083] FIG. 10 is a block diagram of a communication apparatus 1000
according to an embodiment of the present invention.
[0084] Referring to FIG. 10, the communication apparatus 1000
includes a processor 1010, a memory 1020, a radio frequency (RF)
module 1030, a display module 1040, and a user interface module
1050.
[0085] The communication apparatus 1000 is shown for convenience of
description and some modules thereof may be omitted. In addition,
the communication apparatus 1000 may further include necessary
modules. In addition, some modules of the communication apparatus
1000 may be subdivided. The processor 1010 is configured to perform
an operation of the embodiment of the present invention described
with reference to the drawings. For a detailed description of the
operation of the processor 1010, reference may be made to the
description associated with FIGS. 1 to 9.
[0086] The memory 1020 is connected to the processor 1010 so as to
store an operating system, an application, program code, data and
the like. The RF module 1030 is connected to the processor 1010 so
as to perform a function for converting a baseband signal into a
radio signal or converting a radio signal into a baseband signal.
To this end, the RF module 1030 performs analog conversion,
amplification, filtering and frequency up-conversion or inverse
processes thereof. The display module 1040 is connected to the
processor 1010 so as to display a variety of information. As the
display module 1040, although not limited thereto, a well-known
device such as a liquid crystal display (LCD), a light emitting
diode (LED), or an organic light emitting diode (OLED) may be used.
The user interface module 1050 is connected to the processor 1010
and may be configured by a combination of well-known user
interfaces such as a keypad and a touch screen.
[0087] The embodiments of the present invention described above are
combinations of elements and features of the present invention. The
elements or features may be considered selective unless otherwise
mentioned. Each element or feature may be practiced without being
combined with other elements or features. Further, an embodiment of
the present invention may be constructed by combining parts of the
elements and/or features. Operation orders described in embodiments
of the present invention may be rearranged. Some constructions of
any one embodiment may be included in another embodiment and may be
replaced with corresponding constructions of another embodiment. It
is obvious to those skilled in the art that claims that are not
explicitly cited in each other in the appended claims may be
presented in combination as an embodiment of the present invention
or included as a new claim by subsequent amendment after the
application is filed.
[0088] The embodiments of the present invention may be achieved by
various means, for example, hardware, firmware, software, or a
combination thereof. In a hardware configuration, an embodiment of
the present invention may be achieved by one or more ASICs
(application specific integrated circuits), DSPs (digital signal
processors), DSDPs (digital signal processing devices), PLDs
(programmable logic devices), FPGAs (field programmable gate
arrays), processors, controllers, microcontrollers,
microprocessors, etc.
[0089] In a firmware or software configuration, an embodiment of
the present invention may be implemented in the form of a module, a
procedure, a function, etc. Software code may be stored in a memory
unit and executed by a processor. The memory unit is located at the
interior or exterior of the processor and may transmit and receive
data to and from the processor via various known means.
[0090] It will be apparent to those skilled in the art that various
modifications and variations can be made in the present invention
without departing from the spirit or scope of the invention. Thus,
it is intended that the present invention cover the modifications
and variations of this invention provided they come within the
scope of the appended claims and their equivalents.
INDUSTRIAL APPLICABILITY
[0091] Although an example of applying a method and apparatus for
transmitting service preference information from a user equipment
(UE) in a wireless communication system to a 3.sup.rd generation
partnership project (3GPP) long term evolution (LTE) system has
been described, the present invention is applicable to various
wireless communication systems in addition to the 3GPP LTE
system.
* * * * *