US20130107790A1

US20130107790A1 - Method for user equipment transmitting service preference information in wireless communication system and apparatus for same

Info

Publication number: US20130107790A1
Application number: US13/808,471
Authority: US
Inventors: Youngdae Lee; SeungJune Yi; SungDuck Chun; Sungjun PARK; Sunghoon Jung
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2011-04-08
Filing date: 2012-04-05
Publication date: 2013-05-02
Also published as: WO2012138137A2; WO2012138090A3; WO2012138090A2; US20130324129A1; WO2012138137A3; US9432900B2

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.

Description

TECHNICAL FIELD

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

As an example of a wireless communication system to which the present invention is applicable, a 3^rdgeneration partnership project (3GPP) long term evolution (LTE) communication system will be schematically described.
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^rdGeneration Partnership Project; Technical Specification Group Radio Access Network”.
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.
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.
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

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

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.
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.
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.
More preferably, the serving node may be a serving cell and the target node may be a target cell.
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

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.
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

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.

FIG. 2 is a diagram conceptually showing a network structure of an evolved universal terrestrial radio access network (E-UTRAN).

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^rdgeneration partnership project (3GPP) radio access network standard.

FIG. 4 is a diagram showing physical channels used in a 3GPP system and a general signal transmission method using the same.

FIG. 5 is a diagram showing the structure of a radio frame used in a Long Term Evolution (LTE) system.

FIG. 6 is a diagram showing a general transmission and reception method using a paging message.

FIG. 7 is a diagram showing a transmission method of multimedia broadcast multicast service control channel (MCCH) information.

FIG. 8 is a diagram of a wireless communication system including a home eNB (HeNB).

FIG. 9 is a diagram of a handover process based on service preference, according to an embodiment of the present invention.

FIG. 10 is a block diagram of a communication apparatus according to an embodiment of the present invention.

BEST MODE

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.
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.
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.
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.
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.
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.
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.
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.
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.
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).
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).
FIG. 4 is a diagram showing physical channels used in a 3GPP system and a general signal transmission method using the same.
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.
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).
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.
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.
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.
FIG. 5 is a diagram showing the structure of a radio frame used in an LTE system.
Referring to FIG. 5, the radio frame has a length of 10 ms (327200×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×Ts). Ts denotes a sampling time, and is represented by Ts=1/(15 kHz×2048)=3.2552×10⁻⁸(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×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.
Hereinafter, an RRC state of a UE and an RRC connection method will be described.
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.
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.
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.
FIG. 6 is a diagram showing a general transmission and reception method using a paging message.
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.
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.
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).
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.
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.
Hereinafter, a cell selection and cell reselection process will be described.
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.
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.
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.
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.
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.
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.
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.
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.
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.
FIG. 8 is a diagram of a wireless communication system including a HeNB.
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.
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.
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.
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.
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).
FIG. 9 is a diagram of a handover process based on service preference, according to an embodiment of the present invention.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
FIG. 10 is a block diagram of a communication apparatus 1000 according to an embodiment of the present invention.
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.
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.
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.
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.
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.
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.
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

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^rdgeneration 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.

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.