KR20140080279A - Method and apparatus for determining cell selection quality value in wireless communication system - Google Patents

Abstract

Provided are a method and an apparatus for determining a cell selection quality value (Squal) in a wireless communication system having a system bandwidth of greater than or equal to 10 MHz or a maximum acceptance bandwidth of more than 50 resource blocks. A terminal receives a bandwidth gap offset and a wideband reference signal received quality (RSRQ) indicator, from a base station, which indicates whether the terminal can measure wideband RSRQ, measures the RSRQ based on the wideband RSRQ indicator, and determines the cell selection quality value.

Description

TECHNICAL FIELD [0001] The present invention relates to a method and apparatus for determining a cell selection quality value in a wireless communication system,

The present invention relates to wireless communication, and more particularly, to a method and apparatus for determining a cell selection quality value in a wireless communication system.

In a 3rd generation partnership project (3GPP) long term evolution advanced (LTE-A), a user equipment (UE) and an evolved universal terrestrial radio access network (E-UTRAN) are connected in an idle mode and a connected various types of measurements can be performed to support operation in the " mode " mode. The higher layer initializes and controls the measurement of the first layer (L1), i.e., the physical layer. The physical layer provides the measurement capability of the terminal and the network. Measurements can be measured by different measures such as intra-frequency, inter-frequency, inter-system, traffic volume, quality and internal measurements Type. In addition, the measurement can be divided into a measurement performed by the terminal and a measurement performed by the network.

The network transmits a radio resource control (RRC) connection reconfiguration message to the UE to initiate a specific measurement. The RRC connection reconfiguration message may include a measurement identifier (ID), a measurement type, an instruction (set, change, release, etc.), a measurement subject, a measurement quantity, a report amount, and a reporting criterion (periodic / event trigger). If the reporting criteria are met, the terminal sends a measurement report message to the network. The measurement report message may include a measurement ID and a measurement result. In idle mode, measurement information elements (IEs) can be broadcast via system information.

Among the measurement capabilities of the UE, there are a reference signal received power (RSRP) and a reference signal received quality (RSRQ). RSRP is defined as the linear average of the power contribution of resource elements (REs) carrying a cell-specific reference signal (CRS) within the measured frequency bandwidth. In order to measure RSRP, CRS transmitted through antenna port 0 of CRS is used. Also, if the terminal can reliably detect the CRS transmitted via antenna port 1, the CRS transmitted via antenna port 1 can also be used to measure RSRP. The RSRP reference point is the antenna connector of the terminal. If the terminal uses receiver diversity, the value reported to the network can not be less than the RSRP corresponding to any individual diversity.

RSRQ is defined as N * RSRP / (E-UTRA carrier received signal strength indicator (RSSI)). N is the number of resource blocks (RBs) of the E-UTRA carrier RSSI measurement bandwidth. Where measurements in the numerator and denominator are performed over the same set of RBs. The E-UTRA Carrier RSSI includes a linear average of the total received power observed only in orthogonal frequency division multiplexing (OFDM) symbols including reference symbols for antenna port 0 over N RBs within the measurement bandwidth. In this case, the total received power is a signal transmitted from all sources, that is, a co-channel serving cell and a signal transmitted from a neighboring cell, adjacent channel interference ) And thermal noise, and the like. When a specific subframe for performing the RSRQ measurement is indicated by the upper layer, the RSSI can be measured over all OFDM symbols in the indicated subframe. The reference point of RSRQ is the antenna connection of the terminal. If the terminal uses receiver diversity, the value reported to the network can not be less than the RSRP corresponding to any individual diversity. In addition, the measurement of RSRQ may be performed on cells in frequency or on cells in frequency in idle mode.

In general, it is required to measure RSRQ for at least six RBs in the center of a measurement frequency carrier. Since CRS exists over the entire system bandwidth, RSRQ can be measured with respect to the total system bandwidth. However, it is preferable to measure RSRQ for 6 RB considering power consumption or efficiency of the terminal. This is a narrowband RSRQ measurement scheme. The base station can inform the terminal about the maximum allowable bandwidth for measurement through the AllowedMeasBandwidth field transmitted through the upper layer.

The narrowband RSRQ measurement scheme is not a big problem when the serving cell and the neighboring cell of the same channel are configured with the same bandwidth. However, when the bandwidths of the serving cell and the neighboring cell are different from each other, there may occur a gap in which the bandwidths of the serving cell and the neighboring cell do not overlap each other. In particular, when the bandwidth of the serving cell is 10 MHz or more, RB or higher. When RSRQ is measured in this gap, interference from neighboring cells is reflected less and relatively better RSRQ can be measured. That is, an inaccurate RSRQ can be measured differently from the actual RSRQ. In the idle mode, the UE performs cell selection or cell reselection by comparing the cell selection quality value calculated based on the measured RSRQ with a reference quality value received from the base station, RSRQ may cause problems in cell selection or cell reselection.

Therefore, a method for accurately measuring the RSRQ in the idle mode may be required.

It is a technical object of the present invention to provide a method and apparatus for determining a cell selection quality value in a wireless communication system. The present invention provides a method for determining a cell selection quality value by measuring a reference signal received quality (RSRQ) in an idle mode. The present invention provides a method for determining a cell selection quality value by measuring a wideband RSRQ. Alternatively, the present invention provides a method for measuring a narrowband RSRQ and determining a cell selection quality value based on an offset. The present invention proposes a method of performing cell selection or cell reselection based on a determined cell selection quality value.

In one aspect, in a wireless communication system having a system bandwidth of 10 MHz or more or a maximum allowable bandwidth for measurement of 50 resource blocks or more, a cell selection quality value, Squal) is provided. The method includes receiving from the base station a wideband RSRQ measurement indicator and a bandwidth gap offset indicating whether the terminal can measure a wideband RSRQ and measuring an RSRQ based on the wideband RSRQ measurement indicator And determining the cell selection quality value based on the measured RSRQ.

In another aspect, a terminal is provided in a wireless communication system wherein the system bandwidth is at least 10 MHz or the maximum allowed bandwidth for measurement is at least 50 resource blocks (RBs). The terminal includes a radio frequency (RF) unit for transmitting or receiving a radio signal, and a processor coupled to the RF unit, wherein the processor measures a wideband RSRQ (reference signal received quality) And a bandwidth gap offset, measuring a RSRQ based on the wideband RSRQ measurement indicator, and determining a cell selection quality value based on the measured RSRQ .

The cell selection quality value can be determined more accurately.

1 shows a wireless communication system to which the present invention is applied.
2 is a diagram illustrating an example of a cell selection procedure of a UE in an RRC idle state according to the present invention.
FIG. 3 shows that the cell selection range changes according to Q _qualmin .
FIG. 4 shows a case where the bandwidths of the serving cell and the neighboring cell of the same channel are different from each other.
5 shows an embodiment of a system information transmission method according to an embodiment of the present invention.
FIG. 6 shows an example of a method for determining a proposed cell selection quality value according to an embodiment of the present invention.
7 is a block diagram of a wireless communication system in which an embodiment of the present invention is implemented.

Hereinafter, the contents related to the present invention will be described in detail with reference to exemplary drawings and embodiments, together with the contents of the present invention. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference symbols as possible even if they are shown in different drawings. In the following description of the embodiments of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present disclosure rather unclear.

In addition, the present invention will be described with respect to a wireless communication network. The work performed in the wireless communication network may be performed in a process of controlling a network and transmitting data by a system (e.g., a base station) Work can be done at a terminal connected to the network.

1 shows a wireless communication system to which the present invention is applied. This may be referred to as an evolved-UMTS terrestrial radio access network (E-UTRAN), or a long term evolution (LTE) / LTE-A (advanced) system.

Referring to FIG. 1, an E-UTRAN includes a base station (BS) 20 that provides a user plane (UE) with a control plane and a user plane. The terminal 10 may be fixed or mobile and may be referred to by other terms such as a mobile station (MS), a user terminal (UT), a subscriber station (SS), a mobile terminal (MT) . The base station 20 refers to a station that communicates with the terminal 10 and may be called by other terms such as an evolved-NodeB (eNB), a base transceiver system (BTS), an access point, and the like.

The base stations 20 may be interconnected via an X2 interface. The base station 20 is connected to an S-GW (serving gateway) through an S1 (Evolved Packet Core) 30 through an S1 interface, more specifically, through a S1-MME and a S1-U through a mobility management entity (MME). The S1 interface exchanges operation and management (OAM) information to support the movement of the terminal 10 by exchanging signals with the MME.

The EPC 30 is composed of an MME, an S-GW, and a packet data network gateway (P-GW). The MME has information on the connection information of the terminal 10 and the capability of the terminal 10. This information is mainly used for managing the mobility of the terminal 10. [ The S-GW is a gateway having an E-UTRAN as an end point, and the P-GW is a gateway having a PDN as an end point.

The layers of the radio interface protocol between the terminal 10 and the network are divided into three layers based on the lower three layers of an open system interconnection (OSI) The physical layer (PHY) belonging to the first layer may be divided into an information transmission service (physical layer), a physical layer (physical layer), a physical layer and a radio resource control (RRC) layer located in the third layer controls radio resources between the UE 10 and the network. To this end, the RRC layer exchanges RRC messages between the UE 10 and the BS.

The physical layer provides an information transmission service to an upper layer using a physical channel. The physical layer is connected to a medium access control (MAC) layer belonging to the second layer through a transport channel. Data is transferred between the MAC layer and the physical layer through the transport channel. The transport channel is classified according to how the data is transmitted through the air interface.

Data moves between different physical layers, i. E., Between the transmitter and the physical layer of the receiver, over the physical channel. The physical channel is modulated by orthogonal frequency division multiplexing (OFDM), and uses time and frequency as radio resources.

The function of the MAC layer includes a mapping between a logical channel and a transport channel and a multiplexing / demultiplexing into a transport block provided as a physical channel on a transport channel of a MAC SDU (service data unit) belonging to a logical channel. The MAC layer provides a service to a radio link control (RLC) layer through a logical channel.

The function of the RLC layer belonging to the second layer includes concatenation, segmentation and reassembly of the RLC SDU. In order to guarantee various quality of services (QoS) required by a radio bearer (RB), the RLC layer includes a transparent mode (TM), an unacknowledged mode (UM) and an acknowledged mode (AM). and acknowledged mode. AM RLC provides error correction via automatic repeat request (ARQ).

The functions of the packet data convergence protocol (PDCP) layer in the user plane include transmission of user data, header compression and ciphering. The function of the PDCP layer in the user plane includes transmission of control plane data and encryption / integrity protection.

The RRC layer belonging to the third layer is defined only in the control plane. The RRC layer is responsible for the control of logical channels, transport channels and physical channels in connection with the configuration, re-configuration and release of radio bearers. The RB means a logical path provided by the first layer (PHY layer) and the second layer (MAC layer, RLC layer, PDCP layer) for data transfer between the terminal 10 and the network. The setting of the RB means a process of defining characteristics of a radio protocol layer and a channel to provide a specific service, and setting each specific parameter and an operation method. RB can be divided into SRB (signaling RB) and DRB (data RB). The SRB is used as a path for transmitting the RRC message in the control plane, and the DRB is used as a path for transmitting the user data in the user plane.

When there is an RRC connection between the RRC layer of the UE 10 and the RRC layer of the E-UTRAN, the UE 10 is in an RRC CONNECTED state. Otherwise, the RRC IDLE ) State.

The downlink transport channel for transmitting data from the network to the subscriber station 10 includes a broadcast channel (BCH) for transmitting system information and a downlink SCH (shared channel) for transmitting user traffic and control messages. In case of a traffic or control message of the downlink multicast or broadcast service, it may be transmitted through the downlink SCH or may be transmitted through a separate downlink MCH (multicast channel). Meanwhile, an uplink transport channel for transmitting data from the UE 10 to a network includes a random access channel (RACH) for transmitting an initial control message and an uplink shared channel (SCH) for transmitting user traffic or control messages have.

A logical control channel (BCCH), a paging control channel (PCCH), a common control channel (CCCH), a multicast control channel (MCCH), and a multicast traffic channel).

A physical channel is composed of several subcarriers in the frequency domain and a plurality of symbols in the time domain. One subframe consists of a plurality of symbols in the time domain. One subframe is composed of a plurality of resource blocks (RBs), and one resource block is composed of a plurality of symbols and a plurality of subcarriers. In addition, each subframe may use specific subcarriers of a specific symbol (e.g., the first symbol) of the corresponding subframe for a physical downlink control channel (PDCCH), i.e., an L1 / L2 control channel. A transmission time interval (TTI), which is a unit time at which data is transmitted, is 1 ms corresponding to one subframe.

Hereinafter, the RRC state (RRC state) and the RRC connection method of the UE will be described in detail.

The RRC state refers to whether or not the RRC layer of the UE is a logical connection with the RRC layer of the E-UTRAN. If the RRC layer is connected, the RRC connection state is referred to as the RRC idle state. Since the RRC-connected terminal has an RRC connection, the E-UTRAN can grasp the existence of the corresponding terminal on a cell-by-cell basis, thereby effectively controlling the terminal. On the other hand, a terminal in the RRC idle state is not recognized by the E-UTRAN and is managed by the core network in a tracking area (TA) unit, which is an area unit larger than the cell. That is, the presence of the UE in the RRC idle state is detected only in a large area, and it is necessary to move to the RRC connection state in order to receive normal mobile communication services such as voice and data.

When the user turns on the terminal for the first time, the terminal attempts to make a connection with a public land mobile network (PLMN). The particular PLMN that is connected may be selected automatically or manually. Here, the PLMN refers to a wireless communication system for use by a user on the ground traveling in a vehicle or on foot. Or the PLMN may indicate all mobile wireless networks using terrestrial based base stations other than satellites. The home PLMN (HPLMN) is a unique 15-digit code used for identification of individual users of the GSM (global system for mobile communication) network. The MCC (mobile country code) and MNC (mobile network code) are the same PLMN.

An equivalent HPLMN (EHPLMN) list is a PLMN code list that replaces the HPLMN code extracted from the IMSI to allow the provision of multiple HPLMN codes. The EHPLMN list is stored in a universal subscriber identity module (USIM). The EHPLMN list may include an HPLMN code extracted from the IMSI. If the HPLMN code extracted from the IMSI is not included in the EHPLMN list, the HPLMN should be treated as a visited PLMN (VPLMN) when selecting the PLMN. VPLMN is a PLMN different from HPLMN and EHPLMN (if present). A registered PLMN (RPLMN) is a PLMN where certain location registration (LR) results occur. Generally, in a shared network, the RPLMN is a PLMN defined by the PLMN identity of the core network operator that allowed the LR.

The terminal searches for the appropriate cell of the selected PLMN and stays in the RRC idle state in the corresponding cell. The terminal in the RRC idle state selects a cell capable of providing possible services and adjusts it to the control channel of the selected cell. This process is called "camp on a cell". A terminal camp on a cell can read system information and the like from a corresponding cell, and in most cases, it can receive paging information. When the camping is completed, the terminal can register its existence in the registration area of the selected cell. This is called location registration (LR). A terminal regularly registers its presence in a registration area or registers when it enters a new tracking area. The registration area refers to any area where the terminal may roam without a location registration procedure.

If the terminal leaves the service area of the cell or finds a more suitable cell, the terminal reselects and camps the most appropriate cell in the PLMN. If the new cell is included in another registration area, a location registration request is performed. If the terminal moves out of the service area of the PLMN, a new PLMN may be automatically selected or a new PLMN may be manually selected by the user.

The purpose of the terminal in the RRC idle state is as follows.

1) When the terminal receives system information from the PLMN

2) After the terminal initializes the call, it initially connects to the network through the control channel of the camped cell

3) Reception of Paging Message: When the PLMN receives a call to the terminal, the PLMN knows the registration area of the cell where the terminal is camped on. Therefore, the PLMN can send a paging message for the UE through the control channel of all the cells in the registration area. The UE can receive the paging message since the UE has already adjusted to the control channel of the camp-on cell.

4) Receive the cell broadcasting message

A cell in which an idle terminal camps on can be classified into several types according to a service type. Here, the service type defines the contents of the service that the terminal proceeds in the idle state. The type of the cell differs depending on the service type provided in the corresponding cell. Service types include limited service, normal service, and operator service.

Limited services are mainly emergency services such as emergency call, earthquake and tsunami warning system (ETWS) or commercial mobile alert system (CMAS). If the terminal can not find a suitable cell for camping on, does not insert a SIM card, or receives a specific response to the location registration request (for example, an illegal terminal), the terminal attempts camp-on regardless of the PLMN "Restricted service" state. A limited service is a service type that can be supported in an acceptable cell. If the terminal finds an allowable cell through cell selection or cell re-selection, the terminal is changed to a "camped on any cell" state. In the camped-on state in any cell, the UE is in the idle state and has completed the cell selection or cell re-selection process, and has selected the cell regardless of the PLMN identity.

A general service is a service corresponding to a public or a normal call, and is applicable to a suitable cell. A suitable cell is a cell when the UE belongs to a specific PLMN. For example, the specific PLMN may be any one of a selected PLMN, a registered PLMN, and a PLMN of the equivalent PLMN list.

When the UE manually or automatically selects a specific PLMN, the specific PLMN is referred to as a selected PLMN. If the terminal belongs to a selected PLMN, the terminal selects a cell within the selected PLMN. The registered PLMN is a PLMN that the network informs to the terminal through the location registration process.

With respect to the appropriate cell, if the UE finds a suitable cell through cell selection or cell reselection, the terminal is typically changed to a "camped normally" state. Or if the terminal does not find a suitable cell through cell selection or cell reselection, the terminal is changed to an "any cell selection" state. The arbitrary cell selection state is a state in which an attempt is made to search for an allowable cell for all PLMNs corresponding to all radio access technologies (RATs) provided by the UE. If the UE does not find a suitable cell through cell selection or cell re-selection, the UE finds an allowable cell in any PLMN other than the PLMN corresponding to any suitable cell for all supported RATs.

On the other hand, a provider service is a service allowed only by a specific terminal by a provider, and can be supported in a reserved cell.

When the UE in the RRC idle state needs to establish the RRC connection, it establishes the RRC connection with the E-UTRAN through the RRC connection process, and transitions to the RRC connection state. There are many cases where a terminal in the RRC idle state needs to make an RRC connection. For example, uplink data transmission is required due to a user's call attempt or the like, or a response message is transmitted when the paging message is received from the E-UTRAN.

2 is a diagram illustrating an example of a cell selection procedure of a UE in an RRC idle state according to the present invention.

Referring to FIG. 2, the UE selects a PLMN and a RAT to be served (S210). The PLMN and RAT may be selected by the user of the terminal or may use the one stored in the USIM.

In step S220, the UE selects a cell having the largest value among the measured BSs and cells whose strength or quality is higher than a specific value. Then, the base station periodically receives system information. The specific value refers to a value defined in the system in order to guarantee the quality of the physical signal in data transmission / reception. Therefore, the value may vary depending on the applied RAT.

If the network registration is necessary, the terminal registers its own information (e.g., IMSI) in order to receive a service (e.g., paging) from the network (S230, S240). The terminal does not register in the network to which it is connected every time a cell is selected. For example, when system information of a network to be registered (for example, a tracking area identity (TAI) and information of a network known to the user are different), the network is registered.

If the strength or quality of a signal measured from a serving base station is lower than a value measured from a base station of an adjacent cell, the terminal selects another cell that provides better signal characteristics than the cell of the base station to which the terminal is connected S250). This process is called cell reselection by distinguishing the cell selection process such as the initial cell selection in step S220. At this time, there may be a time constraint in order to prevent the cell from being reselected frequently according to the change of the signal characteristics.

The following describes in detail the procedure for the terminal to select a cell.

When the power is turned on or remains in the cell, the terminal performs procedures for selecting and reselecting an appropriate quality cell to receive the service.

The terminal in the RRC idle state should always select a cell of appropriate quality and prepare to receive the service through this cell. For example, a powered down terminal must select a cell of the appropriate quality to register with the network. When the UE in the RRC connection state enters the RRC idle state, the UE must select a cell in the RRC idle state. The process of selecting a cell satisfying a certain condition in order for the UE to enter the service waiting state such as the RRC idle state is called cell selection. It is important to select the cell as quickly as possible, since the cell selection is performed in a state in which the UE does not currently determine the cell to remain in the RRC idle state. Therefore, even if the cell provides the best radio signal quality to the UE, it can be selected in the cell selection process of the UE.

The cell selection process is roughly classified into three types.

First, an initial cell selection process is performed by the UE when the UE does not have prior information on the radio channel. Therefore, the terminal searches all the wireless channels of the EUTRAN band to the extent that the capability of the terminal is allowed to search for an appropriate cell. In each channel, the terminal finds the strongest cell. Then, if the terminal finds a suitable cell satisfying the cell selection criterion, the terminal selects the corresponding cell.

The second cell selection process is a cell selection process that utilizes the stored information. In this process, the UE utilizes the information stored in the UE for the wireless channel, or uses the information broadcast in the cell to select the cell. Therefore, the cell selection can be faster than the initial cell selection process. If the terminal finds a cell satisfying the cell selection criterion, the cell is selected. If the UE does not find a suitable cell satisfying the cell selection criterion, the UE performs an initial cell selection process.

When the UE selects a cell satisfying the cell selection criterion, the UE receives information necessary for the RRC idle state operation of the UE in the corresponding cell from the system information of the cell. After the terminal receives all the information needed for the RRC idle state operation, it waits in idle mode to request a service (e.g., originating call) from the network or to receive a service (e.g., terminating call) from the network.

The third cell selection process is a cell selection process due to the leaving of the RRC connection state. This process is as follows. If the terminal is changed from the RRC connection state to the idle state, (a) if the RRC connection release message includes redirectedCarrierInfo, the terminal selects an appropriate cell according to the redirectedCarrierInfo and attempts camp-on. Here, if the terminal does not find a suitable cell, the terminal can search for and camp on any suitable cell according to the designated RAT.

In step (a), if the RRC connection release message does not include redirectedCarrierInfo, the terminal searches for an appropriate cell on the EUTRA carrier. Here, if the UE does not find a suitable cell, the UE starts to select the stored information cell to search for a suitable cell and performs a cell selection process.

(B) if redirectedCarrierInfo is included in the RRC connection release message, the mobile station sets the allowable cell in the allowable cell according to the redirectedCarrierInfo, and if the mobile station is camped on the arbitrary cell, Try on. Here, if the terminal does not find an allowable cell, the terminal can search for and camp on any allowable cell according to the designated RAT.

In (b) again, if the RRC disconnect message does not include redirectedCarrierInfo, the terminal causes the EUTRA carrier to search for an allowable cell. Here, if the UE does not find an allowable cell, the UE proceeds to search for an allowable cell in any PLMN in an arbitrary cell selected state.

Once the UE has selected a cell through the cell selection process, the strength or quality of the signal between the UE and the BS may be changed due to mobility of the UE or change of the radio environment. Thus, if the quality of the selected cell degrades, the terminal may select another cell that provides better quality. When the cell is reselected in this way, a cell is selected that generally provides better signal quality than the currently selected cell. This process is called cell reselection. The cell reselection process has a basic purpose in terms of quality of a radio signal, in general, to select a cell that provides the best quality to the terminal. That is, the cells searched by the cell reselection are cells satisfying the cell reselection criteria. If a good cell is found, the terminal reselects the good cell. A change in the cell may mean a change in the RAT.

The cell reselection may be performed in a network-dependent manner in addition to the quality of the radio signal as described above. According to this, the network can determine the priority for each frequency and notify the terminal. The UE receiving this priority preferentially takes priority over the radio signal quality criterion in the cell reselection process.

Information on absolute priority for different EUTRAN frequencies or inter-RAT frequencies may be transmitted by system information, RRC Disconnect message. The system information may optionally include the priority information. The RRC disconnect message may include a dedicated priority. Alternatively, the information on the absolute priority may be inherited from another RAT when the UE reselects the inter-RAT cell. It follows the specifications specified in the existing RAT.

If a terminal receives a priority through dedicated signaling, the priority given through the system information is ignored. In other words, if the base station receives the priority through the RRC connection release message from the base station, the terminal ignores the priority received from the system information.

If the terminal is camped on any cell, the terminal shall apply only the priority received through the system information. Therefore, the priority received through dedicated signaling is preserve only unless specified otherwise.

If the terminal sets the other frequency band except for the currently connected frequency band as the dedicated priority in the camp-on state, the terminal regards the current frequency band as the lowest priority.

In order for the UE to initially perform cell selection to camp on a specific cell in the idle mode or to perform cell reselection for a cell having better performance than the current cell, This should be above a certain level. At this time, the power level that can be a criterion for cell selection or cell reselection can be expressed as Srxlev. The quality level that can serve as a basis for cell selection or cell reselection can be expressed as Squal.

The cell selection criterion used by the UE in cell selection or cell re-selection is expressed by Equation (1).

&Quot; (1) "

Srxlev> 0 and Squal> 0

Where Srxlev = _Qrxlevmeas- ( _Qrxlevmin + _{Qrxlevminoffset} ) - Pcompensation. Squal = Q _qualmeas - (Q _qualmin + Q _{qualminoffset} ). The description of each parameter is shown in Table 1.

Srxlev Cell selection Receive level value (dB) Squal Cell selection quality value (dB) Q _rxlevmeas The measured cell reception level (RSRP) Q _qualmeas The measured cell quality (RSRQ) Q _rxlevmin Minimum required receive level (dBm) in the cell Q _qualmin Minimum required quality level in cell (dBm) Q _{rxlevminoffset} As a result of a periodic search for a high priority PLMN while camping on VPLMN, an offset for Q _rxlevmin in _Srxlev Q _{qualminoffset} As a result of the periodic search for a high priority PLMN while camping on VPLMN, the offset for Q _qualmin in _Squal Pcompensation max (P _EMAX - P _PowerClass , 0) (dB) P _EMAX The maximum transmit power level (dBm) that the terminal can use when transmitting on the uplink from the cell. P _PowerClass The maximum RF output power (dBm) according to the power class of the terminal

Referring to equations (1) and (1), the cell selection criterion can be satisfied when both Srxlev and Squal are greater than zero. That is, if the measured RSRP and RSRQ of the measured cell are both higher than a predetermined level, the UE can determine that the cell has a basic possibility for cell selection. In particular, Squal is a parameter corresponding to RSRQ. That is, Squal is a value calculated in relation to the quality of the power, not simply the magnitude of the power measured in the cell. When Squal > 0, the cell selection criterion can be satisfied in terms of cell quality. If the measured RSRQ is _equal to or greater than the sum of Q _qualmin and Q qualminoffset, the cell selection criterion for RSRQ can be satisfied.

On the other hand, in Table 1, Q _qualmin can have the following meaning.

FIG. 3 shows that the cell selection range changes according to Q _qualmin .

Referring to FIG. 3, it is assumed that a point having the same RSRQ is expressed in a circle, but this is for convenience of explanation. The point having the same RSRQ in the actual RSRQ measurement may not be circular. In Fig. 3, Q _qualmin = A and Q _qualmin = B are displayed, and A > B. If Q _qualmin is set to a relatively small value such as B, the cell selection criterion can be satisfied even if the UE measures the quality corresponding to a smaller RSRQ. Therefore, the range in which the UE can perform the cell selection can be widened. On the other hand, if Q _qualmin is set to a relatively large value such as A, the cell selection criterion can be satisfied only when the UE measures quality corresponding to a larger RSRQ. Therefore, the range in which the UE can perform the cell selection can be narrowed. If Q _qualmin is set too large for a base station supplier or a provider, the cell size is reduced. Also, if Q _qualmin is too small, there is a possibility of performing cell selection or cell reselection in an area too large compared to the actual quality, so that actual quality of service may be degraded because the actual camp-on or connection is not performed properly. Therefore, it is important to set an appropriate Q _qualmin and inform it to the terminal.

The cell selection criterion of Equation (1) is a reference value used when a terminal selects a cell, and the reference value can be regarded as 0. The terminal can select the cell when Srxlev and Squal are larger than the reference value of 0. Alternatively, the reference value may be a value other than 0 at the time of cell reselection or measurement. The UE can reselect the cell when Srxlev and Squal are larger than a non-zero reference value. These values may be received from the base station via system information such as SIB3 or SIB5. The comparison method for cell reselection and the like will be described later.

Meanwhile, the terminal can receive various parameters used in Equation (1) and Table 1 through system information such as SIB (system information block) 3, SIB 5, and the like. The UE can perform cell selection or cell reselection using a squal calculated based on Q _qualmin and a reference value or a threshold associated with the squal received through the system information. The UE can perform cell selection or cell re-selection in consideration of priority or the like among cells satisfying the cell selection condition.

FIG. 4 shows a case where the bandwidths of the serving cell and the neighboring cell of the same channel are different from each other.

Referring to FIG. 4A, the bandwidth of the serving cell E-UTRAN is 10 MHz, and the bandwidth of the neighboring cell E-UTRAN is 5 MHz. The first and second bandwidths of 5 MHz used by the neighboring cell are included in the bandwidth of the serving cell at 10 MHz. Considering the band that can not be used on either side of the 5 MHz bandwidth of the neighboring cell, the actual first and second bandwidths can be reduced to about 4.5 MHz respectively. At this time, the bandwidth gap between the first bandwidth and the second bandwidth of the neighboring cell may be calculated as 5- (4.5 + 4.5) /2=0.5 MHz. If the bandwidth of the serving cell E-UTRAN is 20 MHz and the bandwidth of the neighboring cell E-UTRAN is 10 MHz, the bandwidth gap between the first bandwidth and the second bandwidth of the neighboring cell is 10- (9 + 9) / 2 = 2 MHz. This is much larger than 6 RB (= 1.08 MHz), which is the basis of RSRQ measurement.

Referring to FIG. 4 (b), the bandwidth of the serving cell E-UTRAN is 10 MHz and the bandwidth of the neighboring cell UTRAN is 3.84 MHz. The first and second bandwidths of 3.84 MHz used by the neighboring cell are included in the bandwidth of the serving cell at 10 MHz. At this time, the bandwidth gap between the first bandwidth and the second bandwidth of the neighboring cell may be calculated as 5- (3.84 + 3.84) /2=1.16 MHz. Is also greater than 6 RB.

If the bandwidth of the serving cell and the neighboring cell of the same channel are different from each other, if the narrow band RSRQ is measured in the 6 RB according to the conventional method, the interference from the neighboring cell in the bandwidth gap can not be correctly received. That is, when the bandwidth gap is 6 RB or more, it is determined that the amount of interference from the neighboring cell is less than the actual interference amount, so that the RSSI can be calculated to be less than the actual amount, and as a result, the RSRQ can be calculated to be larger than the actual amount. have. When the UE in the idle mode performs cell selection or cell re-selection using the thus-calculated RSRQ, a problem may occur in cell selection or cell re-selection. That is, there may occur a case where the cell reselection is performed later than required by the incorrectly measured RSRQ.

Hereinafter, when the UE of the idle mode measures the RSRQ and determines the cell selection quality value based on the measured RSRQ, the UE performs the correction on the cell selection quality value determined based on the narrowband RSRQ, A method for determining the cell selection quality value based on the wideband RSRQ will be described. In the following description, an embodiment of the present invention may be applied when the bandwidth is 10 MHz or more, or when AllowedMeasBandwidth indicates 50 RB or more.

1) First, when the system bandwidth is 10 MHz or more and the UE determines the cell selection quality value by measuring the narrowband RSRQ, the narrowband RSRQ may be calculated to be less than the actual value. As described above, RSRQ is defined as N * RSRP / (E-UTRA carrier RSSI). At this time, the RSSI corresponds to the sum of all the signals measured by the UE and also includes an interference signal from the neighboring cell. However, when the system bandwidth is 10 MHz or more, RSSI is measured based on 6 RB, and the amount of interference from neighboring cells is judged to be smaller than the actual amount, resulting in a smaller RSSI. Therefore, RSRQ can be calculated to be larger than actual. Therefore, a cell selection quality value can be determined by adding a value capable of correcting it. Equation (2) shows an example of a formula for determining a cell selection quality value according to an embodiment of the present invention.

&Quot; (2) "

Squal = Q _qualmeas - (Q _qualmin + Q _{qualifyingapoffset} + Q _{qualminoffset} )

Referring to Equation (2), a Q _{qualifyingapoffset which} is an offset considering a bandwidth gap is added when determining a cell selection quality value. That is, the cell selection quality value may be determined to be smaller than when the cell selection quality value is determined based only on the RSRQ by the offset Q _{qualifyingapoffset} . If the _{allowedMeasBandwidth} indicates 50 RB or more, if the cell selection quality value is determined by considering only the RSRQ without considering the Q _{qualifyingapoffset} , the cell selection quality value . For this purpose, when the cell selection quality value is determined, a Q _{qualifyingapoffset} corresponding to a certain portion of the applied value may be additionally used to correct the distortion in which the RSRQ becomes large. This is to solve the problem that occurs when the existing narrow-band RSRQ is measured even though the allowedMeasBandwidth indicates 50 RB or more.

2) Alternatively, the UE may determine the cell selection quality value by measuring the wideband RSRQ. In case of a terminal capable of measuring a wideband RSRQ, a wideband RSRQ measurement is possible when the terminal has a system bandwidth of 50 RB or more, and a squal can be determined when measuring a wideband RSRQ. Equation 3 shows another example of an equation for determining a cell selection quality value according to an embodiment of the present invention.

&Quot; (3) "

Squal = Q _qualmeas - (Q _qualmin + Q _{qualminoffset} ) and broadband RSRQ measurement

The wideband RSRQ can be measured by Equation (3). That is, the formula for determining the existing cell selection quality value is used as it is, and the cell selection quality value can be determined by applying it to the wide band.

Equation (4) shows another example of a formula for determining a cell selection quality value according to an embodiment of the present invention.

&Quot; (4) "

Squal = Q _qualmeas - (Q _qualmin + Q _{qualmingapoffset} + Q _{qualminoffset} ) and broadband RSRQ measurement

The wideband RSRQ can be measured by Equation (4). However, Q _{qualificationapoffset} = 0.

5 shows an embodiment of a system information transmission method according to an embodiment of the present invention.

Referring to FIG. 5, in step S100, the BS transmits a wideband RSRQ measurement indicator to the MS. In step S110, the UE measures the wideband RSRQ based on the wideband RSRQ measurement indicator.

The base station may transmit a wideband RSRQ measurement indicator to inform the terminal whether a wideband RSRQ measurement is available and / or a Q _{qualifyingapoffset} . The wideband RSRQ measurement indicator may be broadcast through the system information.

Table 2 shows an example of SIB 1 including a wideband RSRQ measurement indicator in accordance with an embodiment of the present invention.

- ASN1START

SystemInformationBlockType1 :: = SEQUENCE {
...
}

[[widebandRSRQMeas-r11 ENUMERATED {enabled} OPTIONAL- - Cond WB-RSRQ
]]

CellSelectionInfo-v920 :: = SEQUENCE {
q-QualMin-r9 Q-QualMin-r9,
q-QualMinOffset-r9 INTEGER (1..8) OPTIONAL - Need OP
}

CellSelectionInfo-v11 :: = SEQUENCE {
q-QualMinGapOffset-r9 Q-QualMinGapOffset-r11, OPTIONAL - Need OP
}

Referring to Table 2, the wideband RSRQmas field indicates a wideband RSRQ measurement indicator. The widebandRSRQmas field may indicate whether broadband RSRQ measurement is available. That is, when the value of the wideband RSQ field is set to enable, the UE measures the wideband RSRQ if the UE can measure the wideband RSRQ. The widebandRSRQmas field may only exist if allowedMeasBandwidth indicates 50 RB or more. In addition, the q-QualminGapOffset field may be additionally transmitted in addition to the wideband RSRQmas field. The q-QualminGapOffset field indicates the offset to compensate for the resulting difference in RSRQ measurements if allowedMeasBandwidth indicates 50 RB or more and the UE measures the narrowband RSRQ.

On the other hand, transmitting a wideband RSRQ measurement indicator through the system information may be unnecessary for a terminal that does not use it. Therefore, instead of transmitting the wideband RSRQ measurement indicator through the system information, the terminal allowed to perform the wideband RSRQ measurement in the existing connection mode can be determined to be able to perform the wideband RSRQ measurement even in the idle mode. At this time, when the terminal is changed from the connection mode to the idle mode, the terminal can grasp not only the cell but also the status of the cell connected and used by the terminal during that time. That is, the UE can store information on a cell connected in the connection mode when the UE changes from the connection mode to the idle mode. The UE can determine whether it is the cell that allowed the conventional measurement of the wideband RSRQ in the process of reselecting a specific cell or the like. Therefore, in a cell that is allowed to measure the wideband RSRQ in the connected mode, the UE can be determined to be able to perform the wideband RSRQ measurement for cell reselection and the like even in the idle mode.

Table 3 shows an example of a SIB 3 including a wideband RSRQ measurement indicator according to an embodiment of the present invention.

- ASN1START

SystemInformationBlockType3 :: = SEQUENCE {
...

intraFreqCellReselectionInfo SEQUENCE {
q-RxLevMin Q-RxLevMin,
p-Max P-Max OPTIONAL, - Need OP
s-IntraSearch ReselectionThreshold OPTIONAL, - Need OP
allowedMeasBandwidth AllowedMeasBandwidth OPTIONAL, - Need OP
presenceAntennaPort1 PresenceAntennaPort1,
neighCellConfig NeighCellConfig,
t-ReselectionEUTRA T-Reselection,
t-ReselectionEUTRA-SF SpeedStateScaleFactors OPTIONAL
widebandRSRQMeas-r11 ENUMERATED {enabled} OPTIONAL - Cond WB-RSRQ
- Need OP
},
...,
lateNonCriticalExtension OCTET STRING OPTIONAL, - Need OP
[[s-IntraSearch-v920 SEQUENCE {
s-IntraSearchP-r9 ReselectionThreshold,
s-IntraSearchQ-r9 ReselectionThresholdQ-r9
} OPTIONAL, - Need OP
s-NonIntraSearch-v920 SEQUENCE {
s-NonIntraSearchP-r9 ReselectionThreshold,
s-NonIntraSearchQ-r9 ReselectionThresholdQ-r9
} OPTIONAL, - Need OP
q-QualMin-r9 Q-QualMin-r9 OPTIONAL, - Need OP
q-QualMinGapOffset-r9 Q-QualMinGapOffset-r11, OPTIONAL - Need OP

threshServServiceLowQ-r9 ReselectionThresholdQ-r9 OPTIONAL - Need OP
]]

}

Referring to Table 3, the wideband RSRQmas field indicates a wideband RSRQ measurement indicator. The widebandRSRQmas field may indicate whether broadband RSRQ measurement is available. That is, when the value of the wideband RSQ field is set to enable, the UE measures the wideband RSRQ if the UE can measure the wideband RSRQ. The widebandRSRQmas field may only exist if allowedMeasBandwidth indicates 50 RB or more. In addition, the q-QualminGapOffset field may be additionally transmitted in addition to the wideband RSRQmas field. The q-QualminGapOffset field indicates the offset to compensate for the resulting difference in RSRQ measurements if allowedMeasBandwidth indicates 50 RB or more and the UE measures the narrowband RSRQ.

Table 4 shows an example of a SIB 5 including a wideband RSRQ measurement indicator according to an embodiment of the present invention.

- ASN1START

SystemInformationBlockType5 :: = SEQUENCE {
interFreqCarrierFreqList InterFreqCarrierFreqList,
...,
lateNonCriticalExtension OCTET STRING OPTIONAL - Need OP
}

InterFreqCarrierFreqList :: = SEQUENCE (SIZE (1..maxFreq)) OF InterFreqCarrierFreqInfo

InterFreqCarrierFreqInfo :: = SEQUENCE {
dl-CarrierFreq ARFCN-ValueEUTRA,
q-RxLevMin Q-RxLevMin,
p-Max P-Max OPTIONAL, - Need OP
t-ReselectionEUTRA T-Reselection,
t-ReselectionEUTRA-SF SpeedStateScaleFactors OPTIONAL, - Need OP
threshX-High ReselectionThreshold,
threshX-Low ReselectionThreshold,
allowedMeasBandwidth AllowedMeasBandwidth,
presenceAntennaPort1 PresenceAntennaPort1,
cellReselectionPriority CellReselectionPriority OPTIONAL, - Need OP
neighCellConfig NeighCellConfig,
q-OffsetFreq Q-OffsetRange DEFAULT dB0,
interFreqNeighCellList InterFreqNeighCellList OPTIONAL, - Need OR
interFreqBlackCellList InterFreqBlackCellList OPTIONAL, - Need OR
...,
widebandRSRQMeas-r11 ENUMERATED {enabled} OPTIONAL - Cond WB-RSRQ

[[q-QualMin-r9 Q-QualMin-r9 OPTIONAL, - Need OP
q-QualMinGapOffset-r9 Q-QualMinGapOffset-r11, OPTIONAL - Need OP

threshX-Q-r9 SEQUENCE {
threshX-HighQ-r9 ReselectionThresholdQ-r9,
threshX-LowQ-r9 ReselectionThresholdQ-r9
} OPTIONAL - Cond RSRQ
]]
}

InterFreqNeighCellList :: = SEQUENCE (SIZE (1..maxCellInter)) OF
InterFreqNeighCellInfo

InterFreqNeighCellInfo :: = SEQUENCE {
physCellId PhysCellId,
q-OffsetCell Q-OffsetRange
}

InterFreqBlackCellList :: = SEQUENCE (SIZE (1..maxCellBlack)) OF PhysCellIdRange

- ASN1STOP

Referring to Table 4, the wideband RSRQmas field indicates a wideband RSRQ measurement indicator. The widebandRSRQmas field may indicate whether broadband RSRQ measurement is available. That is, when the value of the wideband RSQ field is set to enable, the UE measures the wideband RSRQ if the UE can measure the wideband RSRQ. The widebandRSRQmas field may only exist if allowedMeasBandwidth indicates 50 RB or more. In addition, the q-QualminGapOffset field may be additionally transmitted in addition to the wideband RSRQmas field. The q-QualminGapOffset field indicates the offset to compensate for the resulting difference in RSRQ measurements if allowedMeasBandwidth indicates 50 RB or more and the UE measures the narrowband RSRQ.

Meanwhile, the UE can evaluate neighbor cells using Srxlev and Squal for cell reselection. The UE can set the following additional conditions to prevent unnecessary measurement from being performed.

1) First, the UE does not perform intra-frequency measurement if srxlev> S _IntraSearchP and Squal> S _IntraSearchQ in the serving cell, and otherwise performs in-frequency measurement.

2) Also, the UE performs a measurement when the priority of neighboring cells is higher than the priority of a serving cell for E-UTRAN inter-frequency or inter-RAT. In addition, E-UTRAN, if the priority of the neighboring cell about between the inter-frequency or RAT is equal to the priority of the serving cell, or low, the mobile station in the serving cell Srxlev> S _{nonIntraSearchP} and Squal> when the S _{nonIntraSearchQ} E-UTRAN inter-frequency or The measurement is not performed between the RATs. Otherwise, the measurement is performed between the E-UTRAN frequencies or between the RATs.

S _IntraSearchQ and S _{nonIntraSearchQ} can be used as a triggering threshold for Squal determined by the UE. That is, S _IntraSearchQ indicates the Squal threshold for in-frequency measurements. S _{nonIntraSearchQ} indicates the Squal threshold for E-UTRAN inter-frequency measurement or inter-RAT measurement. S _IntraSearchQ and S _{nonIntraSearchQ} can be transmitted through system information such as SIB3. When the system bandwidth is 10 MHz or more, squal can be calculated by performing the narrow-band measurement as in the conventional method, and thus the cell reselection may not be normally performed.

In addition, a cell reselection criterion between the E-UTRAN frequency and the RAT can be set. The E-UTRAN inter-frequency and inter-RAT cell reselection criterion may be _varied by Thresh _{Serving, LowQ} indicating the minimum Squal threshold of the serving cell when the UE performs cell reselection with a lower priority frequency or RAT have. That is, Thresh _{Serving, LowQ} means a threshold value of squal that can allow a cell reselection to be performed at a frequency having a low priority or RAT. Thresh _{Serving, LowQ} can be sent via SIB 3.

If there is Thresh _{Serving and LowQ} , the UE shall notify the E-UTRAN frequency or RAT frequency having a priority higher than the priority of the serving frequency if the UE satisfies the cell reselection criterion _{and the camped-} Reselection can be performed. At this time, a cell having a higher priority (E-UTRAN or UTRAN FDD RAT / frequency) satisfies Squal> Thresh _{X, HighQ} during a time interval Treselection _RAT , or a cell having a higher priority (UTRAN TDD RAT / GENRA / CDMA2000 ) The cell reselection criterion can be met if Srxlev> Thresh _{X, highP} is satisfied during this time interval Treselection _RAT . Thresh _{X, HighQ} indicates the Squal threshold of the cell when performing cell reselection with a frequency or RAT having a higher priority than the current serving frequency. That is, Thresh _{X, HighQ} means a threshold value of squares of RAT or a frequency having a high priority compared with the current serving cell. Cell reselection may be performed if Thresh _{X, HighQ} for a period of time is exceeded. Thresh _{X, HighQ} can be sent through SIB 5. Treselection _RAT is the minimum time that a UE must evaluate each cell for cell reselection.

If there is no Thresh _{Serving and LowQ} , the UE shall notify the E-UTRAN frequency or RAT frequency having a priority higher than the priority of the serving frequency if the cell satisfies the cell reselection criterion _{and the camped-} Cell reselection can be performed. At this time, the cell reselection criterion can be satisfied when the frequency having a higher priority or the RAT satisfies Srxlev> Thresh _{X, highP} during the time interval Treselection _RAT .

In addition, cell reselection for an E-UTRAN frequency having the same priority can be performed in the same manner as an in-frequency ranking setting.

If Thresh _{Serving and LowQ} are present, the UE may transmit the E-UTRAN frequency or the RAT frequency having a priority lower than the priority of the serving frequency if the cell satisfies the cell reselection criterion _{and the camped-} Lt; / RTI &gt; cell reselection. During the time interval Treselection _RAT , the serving cell satisfies Squal <Thresh _{Serving, LowQ} and the E-UTRAN or UTRAN FDD RAT / Frequency with low priority satisfies Squal> Thresh _{X, lowQ} , or during the time interval _{Treselection RAT} . Cell reselection criterion can be met if the cell satisfies Squal <Thresh _{Serving, LowQ} and the E-UTRAN or UTRAN FDD RAT / frequency with low priority satisfies Srxlev> Thresh _{X, lowP} . Thresh _{X, lowQ} indicates the Squal threshold of the cell when performing cell reselection with a frequency or RAT having a lower priority than the current serving frequency. That is, Thresh _{X, lowQ} denotes a threshold value of Squal of RAT or a frequency having a low priority compared to the current serving cell. Cell reselection may be performed if Thresh _{X, lowQ} is exceeded for a period of time. Thresh _{X, lowQ} can be sent through SIB 5.

If there is no Thresh _{Serving and LowQ} , the UE shall notify the E-UTRAN frequency or RAT frequency having a priority lower than the priority of the serving frequency if the cell satisfies the cell reselection criterion _{and the camped-} Cell reselection can be performed. During the time interval Treselection _RAT , if the serving cell satisfies Srxlev <Thresh _{Serving, LowP} and the E-UTRAN or UTRAN FDD RAT / Frequency with a low priority satisfies Srxlev> Thresh _{X, lowP} , then the cell reselection criterion is satisfied .

Threshold _{Serving, LowQ} , Thresh _{X, HighQ} and Thresh _{X, and LowQ} are compared with the Squal calculated by the UE similar to the S _IntraSearchQ and S _{nonIntraSearchQ} described above. The triggering threshold is set for the Squal determined by the UE. . When the system bandwidth is 10 MHz or more, squal can be calculated by performing the narrow-band measurement as in the conventional method, and thus the cell reselection may not be normally performed.

Accordingly, in the case of a system bandwidth of 10 MHz or more according to an embodiment of the present invention, a method may be proposed in which an offset is applied to each threshold parameter described above, or a new threshold parameter corresponding to a broadband system is newly defined .

Table 5 shows an example of a SIB 3 that includes an offset of a wideband RSRQ measurement indicator and at least one threshold parameter in accordance with an embodiment of the present invention.

- ASN1START

SystemInformationBlockType3 :: = SEQUENCE {
...

intraFreqCellReselectionInfo SEQUENCE {
q-RxLevMin Q-RxLevMin,
p-Max P-Max OPTIONAL, - Need OP
s-IntraSearch ReselectionThreshold OPTIONAL, - Need OP
allowedMeasBandwidth AllowedMeasBandwidth OPTIONAL, - Need OP
presenceAntennaPort1 PresenceAntennaPort1,
neighCellConfig NeighCellConfig,
t-ReselectionEUTRA T-Reselection,
t-ReselectionEUTRA-SF SpeedStateScaleFactors OPTIONAL
widebandRSRQMeas-r11 ENUMERATED {enabled} OPTIONAL - Cond WB-RSRQ
- Need OP
},
...,
lateNonCriticalExtension OCTET STRING OPTIONAL, - Need OP
[[s-IntraSearch-v920 SEQUENCE {
s-IntraSearchP-r9 ReselectionThreshold,
s-IntraSearchQ-r9 ReselectionThresholdQ-r9
s-IntraSearchQoffset-r11 ReselectionThresholdQ-r9
} OPTIONAL, - Need OP
s-NonIntraSearch-v920 SEQUENCE {
s-NonIntraSearchP-r9 ReselectionThreshold,
s-NonIntraSearchQ-r9 ReselectionThresholdQ-r9
s-NonIntraSearchQOffset-r11 ReselectionThresholdQ-r9
} OPTIONAL, - Need OP
q-QualMin-r9 Q-QualMin-r9 OPTIONAL, - Need OP
q-QualMinGapOffset-r9 Q-QualMinGapOffset-r11, OPTIONAL - Need OP

threshServServiceLowQ-r9 ReselectionThresholdQ-r9 OPTIONAL - Need OP
threshServServiceLowQOffset-r11 ReselectionThresholdQ-r9 OPTIONAL - Need OP

]]

}

Table 5 additionally includes s-IntraSearchQoffset field, s-nonIntraSearchQoffset field, and threshServingLowQOffset field in SIB 3 described in Table 3. [ s-IntraSearchQOffset field indicates an offset to be applied to the S _IntraSearchQ Squal threshold for measuring the frequency. That is, the s-IntraSearchQOffset field is an offset considering a squal error that can occur for s _IntraSearchQ when the system bandwidth is 10 MHz or more. The s-IntraSearchQOffset field may be applied when the system bandwidth is 10 MHz, and the terminal measuring the wideband RSRQ may not use it. The s-nonIntraSearchQOffset field indicates the offset applied to the S- _{NonIntraSearchQ} , the Squal threshold for E-UTRAN inter-frequency measurements or inter-RAT measurements. That is, the s-nonIntraSearchQOffset field is an offset considering a squal error that may occur for s _{nonIntraSearchQ} when the system bandwidth is 10 MHz or more. The s-nonIntraSearchQOffset field may be applied when the system bandwidth is 10 MHz, and the terminal measuring the wideband RSRQ may not use it. The threshServingLowQOffset field indicates an offset applied to Thresh _{Serving, LowQ} indicating a minimum Squal threshold of the serving cell when the UE performs cell reselection with a lower priority frequency or RAT. In other words, the threshServingLowQOffset field is an offset considering a squal error that may occur for Thresh _{Serving and LowQ} when the system bandwidth is 10 MHz or more. The threshServingLowQOffset field may be applied when the system bandwidth is 10 MHz, and the terminal measuring the wideband RSRQ may not use it. As such, the offsets applied to the threshold parameters for the serving cell or neighboring cell can each be indicated.

Table 6 shows an example of a SIB 5 that includes an offset of a wideband RSRQ measurement indicator and at least one threshold parameter in accordance with an embodiment of the present invention.

- ASN1START

SystemInformationBlockType5 :: = SEQUENCE {
interFreqCarrierFreqList InterFreqCarrierFreqList,
...,
lateNonCriticalExtension OCTET STRING OPTIONAL - Need OP
}

InterFreqCarrierFreqList :: = SEQUENCE (SIZE (1..maxFreq)) OF InterFreqCarrierFreqInfo

InterFreqCarrierFreqInfo :: = SEQUENCE {
dl-CarrierFreq ARFCN-ValueEUTRA,
q-RxLevMin Q-RxLevMin,
p-Max P-Max OPTIONAL, - Need OP
t-ReselectionEUTRA T-Reselection,
t-ReselectionEUTRA-SF SpeedStateScaleFactors OPTIONAL, - Need OP
threshX-High ReselectionThreshold,
threshX-Low ReselectionThreshold,
allowedMeasBandwidth AllowedMeasBandwidth,
presenceAntennaPort1 PresenceAntennaPort1,
cellReselectionPriority CellReselectionPriority OPTIONAL, - Need OP
neighCellConfig NeighCellConfig,
q-OffsetFreq Q-OffsetRange DEFAULT dB0,
interFreqNeighCellList InterFreqNeighCellList OPTIONAL, - Need OR
interFreqBlackCellList InterFreqBlackCellList OPTIONAL, - Need OR
...,
widebandRSRQMeas-r11 ENUMERATED {enabled} OPTIONAL - Cond WB-RSRQ

[[q-QualMin-r9 Q-QualMin-r9 OPTIONAL, - Need OP
q-QualMinGapOffset-r9 Q-QualMinGapOffset-r11, OPTIONAL - Need OP

threshX-Q-r9 SEQUENCE {
threshX-HighQ-r9 ReselectionThresholdQ-r9,
threshX-HighQOffset-r11 ReselectionThresholdQ-r9,

threshX-LowQ-r9 ReselectionThresholdQ-r9
threshX-LowQOffset-r11 ReselectionThresholdQ-r9,

} OPTIONAL - Cond RSRQ
]]
}

InterFreqNeighCellList :: = SEQUENCE (SIZE (1..maxCellInter)) OF
InterFreqNeighCellInfo

InterFreqNeighCellInfo :: = SEQUENCE {
physCellId PhysCellId,
q-OffsetCell Q-OffsetRange
}

InterFreqBlackCellList :: = SEQUENCE (SIZE (1..maxCellBlack)) OF PhysCellIdRange

- ASN1STOP

Table 6 additionally includes the threshX-HighQOffset field and the threshX-LowQOffset field in SIB 5 described in Table 4. [ The threshX-HighQOffset field indicates an offset applied to the Squal threshold value Thresh _{X, HighQ} of the corresponding cell when performing cell reselection with a frequency or RAT having a higher priority than the current serving frequency. That is, the threshX-HighQOffset field is an offset considering a squal error that may occur for Thresh _{X and HighQ} when the system bandwidth is 10 MHz or more. The threshX-HighQOffset field may be applied when the system bandwidth is 10 MHz, and the terminal measuring the wideband RSRQ may not use it. The threshX-LowQOffset field indicates an offset applied to the Squal threshold value Thresh _{X, LowQ} of the corresponding cell when performing cell reselection with a frequency or RAT having a lower priority than the current serving frequency. That is, the threshX-LowQOffset field is an offset considering a squal error that may occur for Thresh _{X, LowQ} when the system bandwidth is 10 MHz or more. The threshX-LowQOffset field may be applied when the system bandwidth is 10 MHz, and the terminal measuring the wideband RSRQ may not use it. As such, the offsets applied to the threshold parameters for the serving cell or neighboring cell can each be indicated.

Table 7 shows an example of a SIB 3 that includes at least one threshold parameter corresponding to a wideband RSRQ measurement indicator and a wideband system, in accordance with an embodiment of the present invention.

- ASN1START

SystemInformationBlockType3 :: = SEQUENCE {
...

intraFreqCellReselectionInfo SEQUENCE {
q-RxLevMin Q-RxLevMin,
p-Max P-Max OPTIONAL, - Need OP
s-IntraSearch ReselectionThreshold OPTIONAL, - Need OP
allowedMeasBandwidth AllowedMeasBandwidth OPTIONAL, - Need OP
presenceAntennaPort1 PresenceAntennaPort1,
neighCellConfig NeighCellConfig,
t-ReselectionEUTRA T-Reselection,
t-ReselectionEUTRA-SF SpeedStateScaleFactors OPTIONAL
widebandRSRQMeas-r11 ENUMERATED {enabled} OPTIONAL - Cond WB-RSRQ
- Need OP
},
...,
lateNonCriticalExtension OCTET STRING OPTIONAL, - Need OP
[[s-IntraSearch-v920 SEQUENCE {
s-IntraSearchP-r9 ReselectionThreshold,
s-IntraSearchQ-r9 ReselectionThresholdQ-r9
s-IntraSearchQwb-r11 ReselectionThresholdQ-r11
} OPTIONAL, - Need OP
s-NonIntraSearch-v920 SEQUENCE {
s-NonIntraSearchP-r9 ReselectionThreshold,
s-NonIntraSearchQ-r9 ReselectionThresholdQ-r9
s-NonIntraSearchQwb-r11 ReselectionThresholdQ-r11
} OPTIONAL, - Need OP
q-QualMin-r9 Q-QualMin-r9 OPTIONAL, - Need OP
q-QualMinGapOffset-r9 Q-QualMinGapOffset-r11, OPTIONAL - Need OP

threshServServiceLowQ-r9 ReselectionThresholdQ-r9 OPTIONAL - Need OP
threshServServiceLowQwb-r11 ReselectionThresholdQ-r11 OPTIONAL - Need OP

]]

}

Table 7 shows s-IntraSearchQoffset field, s-nonIntraSearchQoffset field, and threshServingLowQOffset field replaced with s-IntraSearchQwb field, s-nonIntraSearchQwb field and threshServingLowQwb field, respectively, in SIB 3 described in Table 5. The s-IntraSearchQwb field indicates the Squal threshold for in-frequency measurements when the system bandwidth is above 10 MHz. That is, the s-IntraSearchQwb field can replace S _IntraSearchQ for a terminal performing a wideband RSRQ measurement. The s-nonIntraSearchQwb field indicates the Squal threshold for E-UTRAN frequency measurement or RAT measurement when the system bandwidth is above 10 MHz. That is, the s-nonIntraSearchQwb field may replace S _{nonIntraSearchQ} for a terminal performing a wideband RSRQ measurement. The threshServingLowQwb field indicates the minimum Squal threshold of the serving cell when the UE performs cell reselection with a lower priority frequency or RAT when the system bandwidth is 10 MHz or higher. That is, the threshServingLowQwb field may replace Thresh _{Serving, LowQ} for the terminal performing the wideband RSRQ measurement. The threshold parameters for the newly defined serving cell or neighboring cell corresponding to the broadband system can thus be indicated, respectively.

Table 8 shows an example of a SIB 5 including at least one threshold parameter corresponding to a wideband RSRQ measurement indicator and a wideband system in accordance with an embodiment of the present invention.

- ASN1START

SystemInformationBlockType5 :: = SEQUENCE {
interFreqCarrierFreqList InterFreqCarrierFreqList,
...,
lateNonCriticalExtension OCTET STRING OPTIONAL - Need OP
}

InterFreqCarrierFreqList :: = SEQUENCE (SIZE (1..maxFreq)) OF InterFreqCarrierFreqInfo

InterFreqCarrierFreqInfo :: = SEQUENCE {
dl-CarrierFreq ARFCN-ValueEUTRA,
q-RxLevMin Q-RxLevMin,
p-Max P-Max OPTIONAL, - Need OP
t-ReselectionEUTRA T-Reselection,
t-ReselectionEUTRA-SF SpeedStateScaleFactors OPTIONAL, - Need OP
threshX-High ReselectionThreshold,
threshX-Low ReselectionThreshold,
allowedMeasBandwidth AllowedMeasBandwidth,
presenceAntennaPort1 PresenceAntennaPort1,
cellReselectionPriority CellReselectionPriority OPTIONAL, - Need OP
neighCellConfig NeighCellConfig,
q-OffsetFreq Q-OffsetRange DEFAULT dB0,
interFreqNeighCellList InterFreqNeighCellList OPTIONAL, - Need OR
interFreqBlackCellList InterFreqBlackCellList OPTIONAL, - Need OR
...,
widebandRSRQMeas-r11 ENUMERATED {enabled} OPTIONAL - Cond WB-RSRQ

[[q-QualMin-r9 Q-QualMin-r9 OPTIONAL, - Need OP
q-QualMinGapOffset-r9 Q-QualMinGapOffset-r11, OPTIONAL - Need OP

threshX-Q-r9 SEQUENCE {
threshX-HighQ-r9 ReselectionThresholdQ-r9,
threshX-HighQwb-r11 ReselectionThresholdQ-r11,

threshX-LowQ-r9 ReselectionThresholdQ-r9
threshX-LowQwb-r11 ReselectionThresholdQ-r11,

} OPTIONAL - Cond RSRQ
]]
}

InterFreqNeighCellList :: = SEQUENCE (SIZE (1..maxCellInter)) OF
InterFreqNeighCellInfo

InterFreqNeighCellInfo :: = SEQUENCE {
physCellId PhysCellId,
q-OffsetCell Q-OffsetRange
}

InterFreqBlackCellList :: = SEQUENCE (SIZE (1..maxCellBlack)) OF PhysCellIdRange

- ASN1STOP

Table 8 shows that the threshX-HighQOffset field and the threshX-LowQOffset field are replaced with the threshX-HighQwb field and the threshX-LowQwb field, respectively, in SIB 5 described in Table 6. [ The threshX-HighQOffset field indicates the Squal threshold of the corresponding cell when performing a cell reselection with a frequency or RAT having a higher priority than the current serving frequency when the system bandwidth is 10 MHz or more. That is, the threshX-HighQOffset field can replace Thresh _{X and HighQ} for the terminal performing the wideband RSRQ measurement. The threshX-LowQOffset field indicates the Squal threshold of the corresponding cell when performing a cell reselection with a frequency or RAT having a lower priority than the current serving frequency when the system bandwidth is 10 MHz or more. That is, the threshX-LowQOffset field may replace Thresh _{X and LowQ} for the terminal performing the wideband RSRQ measurement. The threshold parameters for the newly defined serving cell or neighboring cell corresponding to the broadband system can thus be indicated, respectively.

FIG. 6 shows an example of a method for determining a proposed cell selection quality value according to an embodiment of the present invention.

In step S400, the terminal receives a wideband RSRQ measurement indicator from the base station. In step S410, the terminal receives at least one offset applied to the threshold parameters from the base station or at least one newly defined threshold parameter corresponding to the wideband system. In step S420, the UE measures the RSRQ based on the wideband RSRQ measurement indicator. In step S430, the UE determines a cell selection quality value based on the measured RSRQ and the at least one offset or the at least one threshold parameter.

7 is a block diagram of a wireless communication system in which an embodiment of the present invention is implemented.

The base station 800 includes a processor 810, a memory 820, and a radio frequency unit 830. Processor 810 implements the proposed functionality, process and / or method. The layers of the air interface protocol may be implemented by the processor 810. The memory 820 is coupled to the processor 810 and stores various information for driving the processor 810. [ The RF unit 830 is coupled to the processor 810 to transmit and / or receive wireless signals.

The terminal 900 includes a processor 910, a memory 920, and an RF unit 930. Processor 910 implements functions, processes and / or methods in accordance with embodiments of the present invention. The layers of the air interface protocol may be implemented by the processor 910. The memory 920 is coupled to the processor 910 and stores various information for driving the processor 910. [ The RF unit 930 is coupled to the processor 910 to transmit and / or receive wireless signals.

Processors 810 and 910 may include application-specific integrated circuits (ASICs), other chipsets, logic circuits, and / or data processing devices. Memory 820 and 920 may include read-only memory (ROM), random access memory (RAM), flash memory, memory card, storage media, and / or other storage devices. The RF units 830 and 930 may include a baseband circuit for processing radio signals. When the embodiment is implemented in software, the above-described techniques may be implemented with modules (processes, functions, and so on) that perform the functions described above. The modules may be stored in memories 820 and 920 and executed by processors 810 and 910. The memories 820 and 920 may be internal or external to the processors 810 and 910 and may be coupled to the processors 810 and 910 in various well known means.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas falling within the scope of the same shall be construed as falling within the scope of the present invention.

Claims (15)

A cell selection quality value (Squal) is determined by a UE in a wireless communication system in which a system bandwidth is 10 MHz or more or a maximum allowable bandwidth for measurement is 50 resource blocks or more In the method,
Receiving a wideband RSRQ measurement indicator and a bandwidth gap offset from the base station indicating whether the terminal can measure a wideband RSRQ (reference signal received quality)
Measuring an RSRQ based on the wideband RSRQ measurement indicator,
And determining the cell selection quality value based on the measured RSRQ. The method according to claim 1,
Wherein the wideband RSRQ measurement indicator and the bandwidth gap offset are received via system information. 3. The method of claim 2,
Wherein the system information is at least one of SIB (system information block) 1, SIB3, and SIB5. The method according to claim 1,
If the wideband RSRQ measurement indicator indicates that the terminal can measure the wideband RSRQ,
The measured RSRQ is a wideband RSRQ,
Wherein the cell selection quality value is determined by the following equation.
Squal = Q _qualmeas - (Q _qualmin + Q _{qualminoffset} )
The squal indicates the cell selection quality value, the Q _qualmeas indicates the wideband RSRQ, the Q _qualmin indicates a minimum required quality level (dBm) in the cell, and the offset for the Qqualmin in the squal. The method according to claim 1,
If the wideband RSRQ measurement indicator indicates that the terminal can not measure the wideband RSRQ,
The measured RSRQ is a narrowband RSRQ,
Wherein the cell selection quality value is determined by the following equation.
Squal = Q _qualmeas - (Q _qualmin + Q _{qualifyingapoffset} + Q _{qualminoffset} )
The Q quality parameter is the cell selection quality value, the Q _qualmeas is the wideband RSRQ, the Q _quality is the minimum required quality level (dBm) in the cell, the Q _{qualityapoffset} is the bandwidth gap offset, Indicates the offset. The method according to claim 1,
Further comprising receiving from the base station at least one offset applied to a threshold parameter that is compared to the cell selection quality value. The method according to claim 6,
The at least one offset may be an offset applied to the _IntraSearchQ , a Squal threshold for intra-frequency measurement, an evolved universal terrestrial radio access network (E-UTRAN) inter- radio access technology) between the offset applied to the S _{nonIntraSearchQ} the Squal thresholds for measurement and Thresh to the terminal indicating at least Squal threshold of the serving cell when performing cell reselection to a better frequency or a RAT that has a lower priority _{Serving, LowQ} . _&Lt; / RTI &gt; The method according to claim 6,
Wherein the at least one offset comprises an offset applied to the Squal thresholds Thresh _{X, HighQ} of the cell when performing cell reselection at a frequency or RAT having a higher priority than the current serving frequency, And an offset applied to the Squal threshold Thresh _{X, LowQ} of the corresponding cell when the cell reselection is performed with a frequency having a rank or a RAT. The method according to claim 1,
Further comprising receiving from the base station at least one newly defined threshold parameter that is compared to the cell selection quality value and corresponds to a wireless communication system in which the system bandwidth is greater than or equal to 10 MHz. 10. The method of claim 9,
The at least one threshold parameter may comprise a Squal threshold for in-frequency measurements, a Squal threshold for E-UTRAN frequency measurement or inter-RAT measurement, and a cell reselection with a frequency or RAT with a lower priority And at least one of a minimum Squal threshold of a serving cell when performed. 10. The method of claim 9,
Wherein the at least one threshold parameter is a frequency or RAT having a lower priority than the current serving frequency and a Squal threshold of the cell and a current serving frequency when performing cell reselection with a higher priority than the current serving frequency, And at least one of the Squal thresholds of the cell when performing cell reselection. The method according to claim 1,
Further comprising performing cell selection or cell reselection to a neighbor cell if the cell selection quality value satisfies a cell selection criterion. In a wireless communication system in which the system bandwidth is 10 MHz or more or the maximum allowable bandwidth for measurement is 50 resource blocks or more,
A radio frequency (RF) unit for transmitting or receiving a radio signal; And
And a processor coupled to the RF unit,
The processor comprising:
Receiving a wideband RSRQ measurement indicator and a bandwidth gap offset from the base station indicating whether the terminal can measure a wideband RSRQ (reference signal received quality)
Measuring an RSRQ based on the wideband RSRQ measurement indicator,
And determine a cell selection quality value based on the measured RSRQ. 14. The method of claim 13,
Wherein the wideband RSRQ measurement indicator and the bandwidth gap offset are received via system information. 15. The method of claim 14,
Wherein the system information is at least one of a system information block (SIB) 1, a SIB 3, and a SIB 5.

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