KR20160058677A - Methods for measuring a channel in an unlicensed band and Apparatuses thereof - Google Patents
Methods for measuring a channel in an unlicensed band and Apparatuses thereof Download PDFInfo
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- KR20160058677A KR20160058677A KR1020150145113A KR20150145113A KR20160058677A KR 20160058677 A KR20160058677 A KR 20160058677A KR 1020150145113 A KR1020150145113 A KR 1020150145113A KR 20150145113 A KR20150145113 A KR 20150145113A KR 20160058677 A KR20160058677 A KR 20160058677A
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Abstract
The present invention relates to a channel measurement method and apparatus for a terminal. More particularly, the present invention relates to a method and apparatus for channel search and signal processing for applying LTE technology in a license-exempt frequency band. In particular, the present invention provides a method for a terminal to measure channel conditions, the method comprising: receiving measurement configuration information for channel state measurement of a channel using a license-exempt band frequency from a base station; Measuring a channel state for a representative one of the at least one channel and transmitting a measurement report including a channel state measurement result; and adding an additional channel to the secondary cell among the one or more channels using the license- Receiving the configuration information, and further configuring a secondary cell.
Description
The present invention relates to a channel measurement method and apparatus for a terminal. More particularly, the present invention relates to a method and apparatus for channel search and signal processing for applying LTE technology in a license-exempt frequency band.
As communications systems evolved, consumers, such as businesses and individuals, used a wide variety of wireless terminals. In a mobile communication system such as LTE (Long Term Evolution) and LTE-Advanced of the current 3GPP series, a high-speed and large-capacity communication system capable of transmitting and receiving various data such as video and wireless data outside a voice- It is required to develop a technique capable of transmitting large-capacity data in accordance with the above-described method. It is possible to efficiently transmit data using a plurality of cells in a method for transmitting a large amount of data.
However, there is a limit to providing a base station to a plurality of terminals that transmit large amount of data using limited frequency resources. In other words, securing a frequency resource that can be used exclusively by a specific service provider is costly.
On the other hand, license-exempt frequency bands that can not be used exclusively by specific operators or specific communication systems can be shared by multiple operators or communication systems. For example, WLAN technology, represented by Wi-Fi, provides data transmission and reception services using frequency resources of the license-exempt band.
Accordingly, there is a growing demand for mobile communication systems that transmit and receive data using a license-exempt frequency band.
SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances and provides a channel quality measurement method and apparatus for a license-exempt frequency band for transmitting and receiving data using a license-exempt frequency band.
It is another object of the present invention to provide a method and apparatus for effectively measuring channel quality of a channel using a plurality of license-exempt frequency bands while maintaining signal processing procedures in a conventional LTE system.
According to another aspect of the present invention, there is provided a method for measuring a channel state of a terminal, the method comprising: receiving measurement configuration information for channel state measurement of a channel using an unlicensed band frequency from a base station; Measuring a channel condition for a representative one of the one or more channels using the license-exempt band frequency, transmitting a measurement report including the channel condition measurement result, and adding the secondary cell to the secondary cell among the one or more channels using the license- Receiving additional configuration information on a channel for the secondary cell, and further configuring a secondary cell.
According to another aspect of the present invention, there is provided a method for controlling a channel state measurement of a terminal in a base station, the method comprising: transmitting measurement configuration information for channel state measurement of a channel using an unlicensed band frequency to the terminal; Receiving a measurement report including a channel state measurement result for a representative channel among the channels and generating additional configuration information for a channel to be added to the terminal among the one or more channels using the license-exempt band frequency as a secondary cell ≪ / RTI >
According to another aspect of the present invention, there is provided a terminal for measuring channel conditions, comprising: a receiver for receiving measurement configuration information for channel status measurement of a channel using a license-exempt band frequency from a base station; A transmitter for transmitting a measurement report including a channel state measurement result, and an additional configuration information for a channel to be added as a secondary cell among one or more channels using the license-exempt band frequency from the base station, And a control unit for further constructing a secondary cell.
According to another aspect of the present invention, there is provided a base station for controlling channel state measurement of a terminal, comprising: a transmitter for transmitting measurement configuration information for channel state measurement of a channel using an unlicensed band frequency to the terminal; A base station apparatus including a receiver for receiving a measurement report including a channel state measurement result for a representative channel and a controller for generating additional configuration information for a channel to be added as a secondary cell to at least one of the channels using the license- Lt; / RTI >
According to the present invention as described above, there is provided an apparatus and method for measuring channel quality for a license-exempt frequency band for transmitting and receiving data using a license-exempt frequency band.
The present invention also provides a method and apparatus for effectively measuring channel quality of a channel using a plurality of license-exempt frequency bands while maintaining signal processing procedures in a conventional LTE system.
1 is a diagram for explaining a procedure for configuring a carrier merging between a UE and a BS.
2 is a diagram illustrating an exemplary measurement configuration information for measuring a channel status for a SCell by a UE.
FIG. 3 is a diagram exemplifying information for configuring a SCell operation in a terminal.
4 is a diagram exemplifying information for releasing the SCell operation configured in the terminal.
5 is a view for explaining a MAC control element for instructing activation or deactivation of a cell configured in the UE.
6 is a diagram for explaining a terminal operation according to an embodiment of the present invention.
7 is a view for explaining a base station operation according to another embodiment of the present invention.
8 is a diagram exemplarily showing a format of a beacon signal including channel utilization ratio information.
FIG. 9 is an exemplary diagram illustrating an operation for tracking a state of a channel using the license-exempt band frequency of the present invention.
10 is an exemplary diagram illustrating an information element of a measurement report including channel utilization information.
11 is a diagram illustrating a configuration of a terminal according to another embodiment of the present invention.
12 is a diagram illustrating a configuration of a base station according to another embodiment of the present invention.
Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. 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 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 invention rather unclear.
Herein, the MTC terminal may mean a terminal supporting low cost (or low complexity) or a terminal supporting coverage enhancement. In this specification, the MTC terminal may mean a terminal supporting low cost (or low complexity) and coverage enhancement. Alternatively, the MTC terminal may refer to a terminal defined in a specific category for supporting low cost (or low complexity) and / or coverage enhancement.
In other words, the MTC terminal may refer to a newly defined 3GPP Release 13 low cost (or low complexity) UE category / type for performing LTE-based MTC-related operations. Alternatively, the MTC terminal may support the enhanced coverage over the existing LTE coverage or the UE category / type defined in the existing
The wireless communication system in the present invention is widely deployed to provide various communication services such as voice, packet data and the like. A wireless communication system includes a user equipment (UE) and a base station (BS, or eNB). The user terminal in this specification is a comprehensive concept of a terminal in wireless communication. It is a comprehensive concept which means a mobile station (MS), a user terminal (UT), an SS (User Equipment) (Subscriber Station), a wireless device, and the like.
A base station or a cell generally refers to a station that communicates with a user terminal and includes a Node-B, an evolved Node-B (eNB), a sector, a Site, a BTS A base transceiver system, an access point, a relay node, a remote radio head (RRH), a radio unit (RU), and a small cell.
That is, in the present specification, a base station or a cell has a comprehensive meaning indicating a part or function covered by BSC (Base Station Controller) in CDMA, Node-B in WCDMA, eNB in LTE or sector (site) And covers various coverage areas such as megacell, macrocell, microcell, picocell, femtocell and relay node, RRH, RU, and small cell communication range.
Since the various cells listed above exist in the base station controlling each cell, the base station can be interpreted into two meanings. i) the device itself providing a megacell, macrocell, microcell, picocell, femtocell, small cell in relation to the wireless region, or ii) indicating the wireless region itself. i indicate to the base station all devices that are controlled by the same entity or that interact to configure the wireless region as a collaboration. An eNB, an RRH, an antenna, an RU, an LPN, a point, a transmission / reception point, a transmission point, a reception point, and the like are exemplary embodiments of a base station according to a configuration method of a radio area. ii) may indicate to the base station the wireless region itself that is to receive or transmit signals from the perspective of the user terminal or from a neighboring base station.
Therefore, a base station is collectively referred to as a base station, collectively referred to as a megacell, macrocell, microcell, picocell, femtocell, small cell, RRH, antenna, RU, low power node do.
Herein, the user terminal and the base station are used in a broad sense as the two transmitting and receiving subjects used to implement the technical or technical idea described in this specification, and are not limited by a specific term or word. The user terminal and the base station are used in a broad sense as two (uplink or downlink) transmitting and receiving subjects used to implement the technology or technical idea described in the present invention, and are not limited by a specific term or word. Here, an uplink (UL, or uplink) means a method of transmitting / receiving data to / from a base station by a user terminal, and a downlink (DL or downlink) .
There are no restrictions on multiple access schemes applied to wireless communication systems. Various multiple access schemes such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), OFDM-FDMA, OFDM- Can be used. An embodiment of the present invention can be applied to asynchronous wireless communication that evolves into LTE and LTE-Advanced via GSM, WCDMA, and HSPA, and synchronous wireless communication that evolves into CDMA, CDMA-2000, and UMB. The present invention should not be construed as limited to or limited to a specific wireless communication field and should be construed as including all technical fields to which the idea of the present invention can be applied.
A TDD (Time Division Duplex) scheme in which uplink and downlink transmissions are transmitted using different time periods, or an FDD (Frequency Division Duplex) scheme in which they are transmitted using different frequencies can be used.
In systems such as LTE and LTE-Advanced, the uplink and downlink are configured on the basis of one carrier or carrier pair to form a standard. The uplink and the downlink are divided into a Physical Downlink Control Channel (PDCCH), a Physical Control Format Indicator CHannel (PCFICH), a Physical Hybrid ARQ Indicator CHannel, a Physical Uplink Control CHannel (PUCCH), an Enhanced Physical Downlink Control Channel (EPDCCH) Transmits control information through the same control channel, and is configured with data channels such as PDSCH (Physical Downlink Shared CHannel) and PUSCH (Physical Uplink Shared CHannel), and transmits data.
On the other hand, control information can also be transmitted using EPDCCH (enhanced PDCCH or extended PDCCH).
In this specification, a cell refers to a component carrier having a coverage of a signal transmitted from a transmission point or a transmission point or transmission / reception point of a signal transmitted from a transmission / reception point, and a transmission / reception point itself .
The wireless communication system to which the embodiments are applied may be a coordinated multi-point transmission / reception system (CoMP system) or a coordinated multi-point transmission / reception system in which two or more transmission / reception points cooperatively transmit signals. antenna transmission system, or a cooperative multi-cell communication system. A CoMP system may include at least two multipoint transmit and receive points and terminals.
The multi-point transmission / reception point includes a base station or a macro cell (hereinafter referred to as 'eNB'), and at least one mobile station having a high transmission power or a low transmission power in a macro cell area, Lt; / RTI >
Hereinafter, a downlink refers to a communication or communication path from a multipoint transmission / reception point to a terminal, and an uplink refers to a communication or communication path from a terminal to a multiple transmission / reception point. In the downlink, a transmitter may be a part of a multipoint transmission / reception point, and a receiver may be a part of a terminal. In the uplink, the transmitter may be a part of the terminal, and the receiver may be a part of multiple transmission / reception points.
Hereinafter, a situation in which a signal is transmitted / received through a channel such as PUCCH, PUSCH, PDCCH, EPDCCH, and PDSCH is expressed as 'PUCCH, PUSCH, PDCCH, EPDCCH and PDSCH are transmitted and received'.
In the following description, an indication that a PDCCH is transmitted or received or a signal is transmitted or received via a PDCCH may be used to mean transmitting or receiving an EPDCCH or transmitting or receiving a signal through an EPDCCH.
That is, the physical downlink control channel described below may mean a PDCCH, an EPDCCH, or a PDCCH and an EPDCCH.
Also, for convenience of description, EPDCCH, which is an embodiment of the present invention, may be applied to the portion described with PDCCH, and EPDCCH may be applied to the portion described with EPDCCH according to an embodiment of the present invention.
Meanwhile, the High Layer Signaling described below includes RRC signaling for transmitting RRC information including RRC parameters.
The eNB performs downlink transmission to the UEs. The eNB includes a physical downlink shared channel (PDSCH) as a main physical channel for unicast transmission, downlink control information such as scheduling required for reception of PDSCH, and uplink data channel A physical downlink control channel (PDCCH) for transmitting scheduling grant information for transmission in a Physical Uplink Shared Channel (PUSCH). Hereinafter, the transmission / reception of a signal through each channel will be described in a form in which the corresponding channel is transmitted / received.
The LTE at Unlicensed spectrum (LTE-U) is a term referring to 3GPP (3rd Generation Partnership Project) standardization for applying LTE technology to the unlicensed spectrum of 5GHz ISM (Industry, Science, Medical). LTE-U can be used to apply LTE Carrier aggregation (CA), Supplement DownLink (SDL), and Dual Connectivity (DC) technologies to licensed spectrum and license-exempt bands. The license-exempted band in this specification refers to a frequency band which can be used by various carriers such as a plurality of carriers or heterogeneous communication schemes in a concept opposite to a licensed band exclusively available to a particular carrier. Thus, the license-exempt band can be set differently according to the country or region, and the present invention is not limited to a specific frequency band. In conclusion, the license-exempt band in the present invention should be understood to include all of the shared frequency bands that can not be used exclusively by a particular provider. Hereinafter, the 5 GHz band will be described as an example for convenience of understanding.
In addition, the license-exempted bands and license-exempted frequency-unlicensed frequency bands in this specification may be written in the same sense and mixed as necessary.
1 is a diagram for explaining a procedure for configuring a carrier merging between a UE and a BS.
The carrier merging procedure in FIG. 1 includes Radio Resource Control (RRC) and Medium Access Control (MAC) messages used for the LTE CA.
In order to exchange information between the
The
The RRC message transmitted in step S120 may include measurement configuration information for SCELL channel measurement of the
As shown in FIG. 2A, the measurement configuration information (MeasConfig) includes a measurement object addition correction list (measObjectToAddModList) information element. As shown in FIG. 2B, the measurement object addition correction list (measObjectToAddModList) information element is transmitted in the form of a sequence, and includes list information about a frequency (or band) to be measured for channel measurement. Further, as shown in FIG. 2C, the measurement object addition correction list (measObjectToAddModList) information element includes identification information about the measurement object and list information about the measurement object. On the other hand, as shown in (D) of FIG. 2, the EUTRA measurement object information element may include frequency information about a carrier to be measured. That is, the SCell measurement configuration information includes an
Referring again to FIG. 1, the
Then, the
That is, in step S135, the
Referring again to FIG. 1, the terminal 110 having the SCell additionally configures the additionally configured SCell in a disabled state. Therefore, the
Thereafter, the terminal 110 can transmit and receive data through SCell (
The terminal 110 may receive the MAC CE including the deactivation indication information through the SCELL or the SCELLDeactivationTimer described above (S165), and deactivate the SCELL (S166).
Thereafter, the
Specifically, the third RRC message used in FIG. 1 may be used to cancel the CA operation. That is, the RRC message in step S175 may include the SCell information used in the CA. For example, as shown in FIG. 4A, the RRCConnectionReconfigurationComplete message may include an sCellToReleaseList information element, and the sCellToReleaseList information element may include index information of a SCell to be released as shown in FIG. 4B. The
As described above, the UE can add and release SCell through RRC message exchange and channel measurement with the BS.
However, if SCell is configured with a channel using the license-exempt band frequency, instead of using the same license band frequency as the conventional LTE, a method different from conventional channel measurement may be required. In addition, since there are many available bandwidths of the license-exempt band, there is a need to newly change information for SCell measurement configuration, activation or deactivation, addition / deletion through the conventional RRC message.
For example, an LTE CA assuming operation in the licensed band assumes that there is no other interferer (heterogeneous system) operating in the SCell frequency band. On the other hand, in the 5GHz ISM band which is the SCell target frequency of the LTE-U CA, a heterogeneous system interferer (for example, IEEE 802.11, WLAN station and AP) exists and the amount of interference varies with time and space. In addition, there may be a maximum of 23 available channels on a 20 MHz bandwidth basis, so there is a problem of selecting an optimal channel for SCell selection for CA. These problems can be summarized as follows.
One) SCell To select the band and measure the quality of the band LTE Signal processing Procedural problem
In step S120 and step S125 in FIG. 1, the UE acquires the frequency information (ARFCN-Value EUTRA) of the CA target SCell through RRC Connection Reconfiguration (hereinafter referred to as RRCConnReconf) message exchange with the PCell. After measuring the quality of the corresponding SCell, the UE transmits the reference signal received power (RSRP) and reference signal received quality (RSRQ), which are SCell quality information, through PCell.
However, since the maximum number of available channels in the 5 GHz ISM band, which is the license-exempted band, is 23, the number of SCELLIndex mapped to each measurement object is larger than 16, which is the maximum number of neighbor lists of the target of measurement configuration information Since a maximum of 7 can be set, the number of SCell frequency bands and measurement objects that can be actually transferred to the terminal is limited to seven. Therefore, for the measurement report for the total of 23 available channels, several RRCConnReconf. Procedures are required. In addition, since measurements on the 5 GHz total available channel take a long time and it is not possible to predict when and how much Wi-Fi traffic will occur for each of up to 23 channels, the accuracy of previously measured quality results can not be guaranteed do. That is, in the conventional LTE CA procedure, the measurement configuration for a plurality of channels using the license-exempt band frequency can not be performed with one RRC message, and there is a problem in that a plurality of RRC reconfiguration procedures must be performed. In addition, since a plurality of channels using the license-exempt band frequency may change dynamically and quickly due to traffic of other communication systems, a reliability problem may occur with respect to previously measured channel measurement results.
2) 5 GHz ISM All available in-band SCell Band can not be designated as MAC CE
In step S135 and step S140 in FIG. 1, frequency information (ARFCN-ValueEUTRA) of the CA target SCell is transmitted through the sCellToAddModList information element. If it detects a frequency band that guarantees better performance than the SCell delivered in the previous procedure, the sCellToAddModList should be passed a different ARFCN-ValueEUTRA than the SCell frequency information specified in the SCell measurement configuration step.
In addition, when SCell is configured, instruction information indicating activation must be transmitted through the MAC CE in order to activate the SCell in the inactive state. However, the format of the current MAC CE has a problem in covering the number of channels using the license-exempt band frequency.
Referring to FIG. 5, the maximum number of SCell that can be transmitted to the Activation MAC CE is seven (C1 to C7). As described above, since the maximum number of available channels in the 5 GHz band is 23, the entire available band can not be described as an Activation MAC CE.
3) 5 GHz ISM For the band EUTRA Operating band and EARFCN Problems of definition absence
The E-UTRA operating bands defined in 3GPP TS36.101 do not include the 5GHz ISM band. Therefore, in TS36.101, the EUTRA Absolute Radio-Frequency Channel Number (EARFCN), which refers to the frequency band, is not defined for the 5 GHz ISM band. Therefore, in order to construct a SCELL for a terminal using a license-exempt band frequency, it is necessary to newly define an EARFCN for transmitting information on a channel using an unlicensed band frequency.
In order to solve the problems described above, the present invention utilizes the 5 GHz ISM band to increase a single user transmission rate through LTE-UCA transmission. In addition, the present invention aims to efficiently perform quality measurement on 23 20 MHz LTE-U channels in the 5 GHz ISM band while observing RRC signal processing procedures for existing LTE CAs.
6 is a diagram for explaining a terminal operation according to an embodiment of the present invention.
A method for measuring a channel condition of a terminal of the present invention includes the steps of receiving measurement configuration information for channel state measurement of a channel using an unlicensed band frequency from a base station, Measuring a channel state of a representative channel among the plurality of channels, and transmitting a measurement report including a channel state measurement result; and receiving additional configuration information for a channel to be added as a secondary cell among one or more channels using the license- And further configuring a secondary cell.
Referring to FIG. 6, the terminal includes a step of receiving measurement configuration information for channel state measurement of a channel using an unlicensed band frequency from a base station (S610). For example, the terminal may receive measurement configuration information from the base station to measure the channel status of a channel using the license-exempt band frequency. As described above, the measurement configuration information can be received through the RRC message and received via the RRC Connection Reconfiguration message. In addition, the measurement configuration information may include information about the representative channel of one or more channels using the license-exempt band frequency. For example, only the information on the representative channel determined by the base station among the 23 channels using the license-exempt band frequency can be received and the channel status for the representative channel can be measured. To this end, the base station may determine one representative channel for each license-exempt band or determine one channel representative of the entire license-exempt band.
Meanwhile, the terminal includes a step of measuring a channel state of a representative channel among at least one channel using the license-exempt band frequency based on the measurement configuration information, and transmitting a measurement report including a channel state measurement result (S620). The UE can measure the channel status for the representative channel based on the received measurement configuration information. The channel condition may be measured with a conventional RSRP or RSRQ value, or may be measured with a new value such as energy detection. The terminal transmits a measurement report including the measured channel state measurement result to the base station. As another example, the measurement report may be transmitted to the base station including channel utilization information for each of the one or more channels including the representative channel. In this case, the terminal can measure not only the representative channel but also the channel utilization rate information for each channel indicated by the measurement configuration information.
In step S630, the terminal receives additional configuration information for a channel to be added as a secondary cell among one or more channels using the license-exempt band frequency from the base station, and further configures a secondary cell. The base station can determine the secondary cell for configuring the CA in the terminal based on the measurement report transmitted by the terminal. If the terminal determines the CA by the base station, it can construct the CA by receiving the additional configuration information for the secondary cell. The additional configuration information for the channel to be added to the secondary cell may be received via the RRC message, and may include identification information for the secondary cell and the like. In one example, a channel for addition to a secondary cell may be determined based on channel utilization information for each of the one or more channels. For example, the channel utilization information may be measured based on the beacon signal transmitted by the wireless LAN access point, and the beacon signal may include the available bandwidth information.
Meanwhile, the base station may periodically transmit a beacon signal including channel utilization information of a channel to be added to the secondary cell. This makes it possible to prevent occupation of another communication system with respect to the secondary cell that the base station decided to further configure in the terminal. For example, one or more field values of the beacon signal transmitted by the base station may be set to a maximum value. That is, the base station periodically transmits a beacon signal in which each field value is set to a maximum value, thereby preventing occupation of a corresponding secondary cell channel in another communication system.
7 is a view for explaining a base station operation according to another embodiment of the present invention.
The method includes the steps of transmitting measurement configuration information for channel state measurement of a channel using an unlicensed band frequency to the terminal, Receiving a measurement report including channel state measurement results for a representative one of the one or more channels and generating additional configuration information for a channel to be added to the terminal among the one or more channels using the license-exempt band frequency as a secondary cell .
Referring to FIG. 7, the base station includes a step of transmitting measurement configuration information for channel state measurement of a channel using an unlicensed band frequency to a terminal (S710). For example, the base station may generate and transmit measurement configuration information for channel state measurement of a channel using a license-exempt band frequency to the terminal through an RRC message. For example, the measurement configuration information may include information about a representative channel of one or more channels using an unlicensed band frequency. The representative channel may be determined to be one of all unlicensed band channels, and may be determined one by one in each of the license-exempt band bands divided according to a certain condition. The base station can determine the representative channel, and transmit identification information and the like for the determined representative channel to the terminal by including it in the measurement configuration information. There is no limitation on the method of determining the representative channel. The representative channel can be determined as a channel that can represent the channel measurement result for a channel using each license-exempt band frequency. Thus, without transmitting the measurement configuration information for all of the 23 available bandwidths described above, .
In addition, the base station includes receiving a measurement report including a channel state measurement result for the representative one of the one or more channels using the license-exempt band frequency (S720). The base station can receive measurement results for the measured channel based on measurement configuration information through a measurement report. Based on the measurement report, the base station can determine whether the terminal has a CA and what channel to add to the SCell. As another example, the measurement report may include channel utilization information for each of the one or more channels including the representative channel measured by the terminal. That is, the measurement report may include a conventional RSRP or RSRQ value and may include a newly defined energy level or channel utilization information.
In addition, the base station includes a step of generating additional configuration information for a channel to be added as a secondary cell to one of the one or more channels using the license-exempt band frequency (S730). The base station can determine the channel of the SCell to configure the CA in the terminal based on the measurement report. The BS may transmit information on the determined SCell to the UE through the RRC message, and the RRC message may include additional configuration information for SCell addition. To this end, the base station can generate additional configuration information. In one example, a channel for addition to a secondary cell may be determined based on channel utilization information for each of the one or more channels. As described above, the channel utilization rate information may be measured and received by the terminal or may be measured by the base station. The channel utilization information is measured based on the beacon signal transmitted by the wireless LAN access point, and the beacon signal may include the available bandwidth information.
The base station may further include a step of periodically transmitting a beacon signal including channel utilization information of a channel to be added to the secondary cell after determining a SCell to configure the CA in the terminal. The beacon signal transmitted by the base station may include one or more fields, and each field value may be set to a maximum value. Through this, the terminal of the other communication system can receive the beacon signal transmitted by the base station and confirm that the corresponding channel is used by the base station. Therefore, the base station can minimize interference signals from other communication system terminals in the corresponding channel.
As described above, the terminal and the base station of the present invention can solve the problem of insufficient resources for specifying a conventional channel by assigning a representative value to a small number of representative channels in measuring the channel state of a channel using the license-exempt band frequency . Also, the lack of resources for activation or deactivation can be solved. On the other hand, when the SCell is determined, the base station sets the field value of the beacon signal to a maximum value and periodically transmits the beacon signal to the base station, thereby preventing interference signals that may occur in the corresponding channel.
Hereinafter, the operations of the terminal and the base station of the present invention, which have been described with reference to FIGS. 6 and 7, will be described in more detail. In the following description, the physical connection between the PCell and the SCell is separately described. That is, PCell and SCell are classified into a collocated case and a non-collocated case.
PCell and SCell If coexistence
Coexistence means that PCell and SCell are connected to the same DU (digital unit of base station) and operate physically in the same base station, meaning that information can be exchanged internally.
Since the 5 GHz ISM band has 23 total available channels, monitoring the quality of the entire channel in real time complicates the procedure and takes a lot of time. In addition, there is a problem that the reliability of existing measurement results is degraded because of a longer measurement cycle. Accordingly, the present invention proposes a method of measuring a channel by assigning representativeness to one or a small number of 23 channels.
One) EUTRA Operating band and EARFCN New definition
In the present invention, an EUTRA operation band and an EARFCN for the LTE-U CA are newly defined in ARFCN-Value EUTRA, which is an EUTRA carrier frequency defined in TS 36.101. In addition, a method of transmitting ARFCN-Value EUTRA, which is information on one representative channel to which representability is given among 23 available channels, using MeasObjectEUTRA information element is proposed.
According to
Table 1 defines each example, and the EUTRA operation band in the present invention may be determined more than once depending on the country or region.
Of the newly defined channels, since the operating band available for each region is limited, one of the available bands in the corresponding region can be selected as the representative channel. In this case, the Node B forwards the ARFCN-Value EUTRA of the corresponding representative channel to the UE through an RRCConnReconfiguration message for transmitting measurement configuration information for channel state measurement. For example, if only one representative channel is used, the RRCConnReconfiguration message is transmitted to the 5,490-5,510 MHz channel located in the middle of the entire frequency band, that is, ARFCN-ValueEUTRA = 53,300 (center frequency = 5,500 MHz) To the terminal. As another example, if the total band defined in Table 1 can be used and the channel quality of each band is to be measured as accurately as possible, a representative channel is selected one by one in each band, and five ARFCN-Value EUTRAs for that channel are included in the RRCConnReconfiguration message And transmit it to the terminal.
After the UE measures the channel condition for the 20 MHz band of the corresponding center frequency, it transmits RSRP or RSRQ of the corresponding band to the PCell through a measurement report. The PCell base station recognizes the quality of the received representative channel as the channel quality of the entire 5 GHz band or each operating band defined in Table 1.
2) Optimal channel determination method
On the other hand, the base station can determine an optimal channel for further configuration with SCell based on the measurement report including the channel measurement result of the UE.
In the 5 GHz ISM band, due to the channel occupancy of the heterogeneous wireless equipment, the available bandwidth available through that channel will vary. Therefore, the present invention proposes a scheme of using available bandwidth information as a new quality in addition to RSRP and RSRQ which are used as channel quality indicators in existing LTE. The method of using the available bandwidth information also has an advantage that it can be utilized for ensuring equity in sharing and sharing of channels with heterogeneous devices sharing the same band of 5 GHz.
Wi-Fi, which is a technology mainly considered as a heterogeneous wireless device, will be described as an example.
8 is a diagram exemplarily showing a format of a beacon signal including channel utilization ratio information. Referring to FIG. 8, a beacon signal can be transmitted by each Wi-Fi AP. Alternatively, after the SCell is configured in the UE, the BS may transmit the data as needed. Specifically, each Wi-Fi AP transmits the available bandwidth of the Wi-Fi cell measured as a cumulative average through a beacon frame in a channel utilization field. A Wi-Fi terminal can receive a beacon frame transmitted by a Wi-Fi AP operating in each channel and select a specific AP to access.
The channel Utilization can be calculated as shown in
[Equation 1]
Channel utilization = (channel busy time / (dot11ChannelUtilizationBeaconIntervals x dot11BeaconPeriod x 1024)) x 255
The base station (SCell) tracks a channel having the lowest channel utilization rate among the available channels in the 5 GHz band by receiving the beacon signal received from the nearby Wi-Fi AP or directly measuring the channel utilization rate.
FIG. 9 is an exemplary diagram illustrating an operation for tracking a state of a channel using the license-exempt band frequency of the present invention.
Referring to FIG. 9, the base station (SCell) periodically measures channel utilization of each channel (S910). As described above, the channel utilization rate may be measured by the base station, or may be received by the beacon signal transmitted by each AP.
The BS determines whether the channel utilization ratio (BssLoadCurrent in FIG. 9) of the specific channel is better than the best channel utilization ratio (BssLoadScanned in FIG. 9) measured so far (S920). If it is determined that the channel utilization rate of the specific channel is higher than the best channel utilization rate measured so far (i.e., BssLoadCurrent? BssLoadScanned), it is determined whether the current SCell is activated for the CA (S930). For example, whether the SCell is activated for the CA can be determined by checking whether the SCell is in the RRCConnected state or the MAC activated state. If the SCell is active, the channel utilization rate of another channel is measured according to the existing period. If the SCell is inactive, the BS selects the CA channel (BssLoadCurrent = BssLoadScanned) and transmits information through the RRC message (RRCConnReconf (SCellToAddModList)) S940).
As described above, the BS can track the state of the dhs channel by using the channel utilization rate information, and determine the SCell as the CA channel according to the result of the tracking to be configured in the BS.
3) LTE-U channel access control for heterogeneous equipment
The representative channel selected for the LTE-U channel estimation includes at least one of a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), a Cell-Specific Reference Signal (CRS), and a Physical Broadcast Channel Lt; / RTI > The transmission of the signal is an interference signal from the viewpoint of a heterogeneous apparatus, and normal access is impossible in such an interference environment. Accordingly, in the present invention, access barring for a corresponding channel is induced in the following manner for selecting and communicating a 5 GHz ISM band of a different kind of equipment.
The base station of the present invention can periodically transmit a beacon signal in the SCell determined by the CA. The beacon signal may include the above-described channel utilization rate information, etc., and may be set by setting the value of each field in the beacon signal to a maximum value in order to prevent connection of the dissimilar apparatus.
For example, the SCell operating in the representative channel periodically induces connection prevention by utilizing the BSS Load element of the beacon frame. All field values that can be set for connection prevention among the fields defined in Fig. 8 are changed to the maximum value. That is, an additional non-AP station (for example, a Wi-Fi terminal) can not access the corresponding BSS because the load within the BSS is maximum such as Station Count = 0xFFFF, Channel Utilization = 0xFF, and Available Admission Capacity = 0x0000 do.
As another example, the SCell operating in the representative channel responds without receiving a response (Probe Response frame not transmitted) upon detection of a connection attempt transmitted from a Wi-Fi terminal, i.e., a probe request frame, Channel to prevent it from being affected by the interference by the LTE-U control signal.
PCell and SCell If you do not coexist
The non-coexistence case refers to a case where PCell and SCell are connected to a heterogeneous DU (digital unit of a base station) and physically operate in different base stations, and information can not be exchanged internally.
In the non-coexistence situation, since the PCell can not recognize the optimal channel for the SCell to operate, the UE can perform the optimal channel tracking method of FIG. That is, the UE tracks the channel using the channel utilization rate information for each channel in the same manner as described with reference to FIG. 9, and delivers the tracked result to the PCell through a measurement report (Measurement Report). Then, the PCell recognizing the optimal channel can designate the corresponding optimal channel to SCell through the RRCConnReconfiguration (SCellToAddModList) message, and activate the LTE-U CA or DC.
In this case, a new information element may be required for the UE to transmit the channel utilization rate information for the specific channel to the base station through the measurement report.
10 is an exemplary diagram illustrating an information element of a measurement report including channel utilization information.
Referring to FIG. 10, for example, the UE may add
As described above, according to the present invention, the EUTRA operating band and the EARFCN can be newly defined for the frequency of the entire 5 GHz ISM band, and channel quality can be measured using only one or a few representative bands. In addition, by using the channel usage of the heterogeneous devices using the ISM band as a new channel quality index, it is possible to more equitably share the ISM band between the heterogeneous devices.
Hereinafter, configurations of a terminal and a base station capable of performing all of the operations of the present invention described with reference to FIGs. 1 to 10 will be briefly described with reference to the drawings.
11 is a diagram illustrating a configuration of a terminal according to another embodiment of the present invention.
11, a
The
In addition, the receiving
The
In addition, the
The
12 is a diagram illustrating a configuration of a base station according to another embodiment of the present invention.
Referring to FIG. 12, a
The
The receiving
The
In addition, the
The
Meanwhile, the
The standard content or standard documents referred to in the above-mentioned embodiments constitute a part of this specification, for the sake of simplicity of description of the specification. Therefore, it is to be understood that the content of the above standard content and portions of the standard documents are added to or contained in the scope of the present invention.
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 within the scope of equivalents should be construed as falling within the scope of the present invention.
Claims (24)
Receiving measurement configuration information for channel state measurement of a channel using a license-exempt band frequency from a base station;
Measuring a channel state for a representative one of the one or more channels using the license-exempt band frequency based on the measurement configuration information, and transmitting a measurement report including a channel state measurement result; And
Receiving additional configuration information for a channel to be added as a secondary cell among one or more channels using the license-exempt band frequency from the base station, and further configuring the secondary cell.
Wherein the measurement configuration information comprises:
And information about a representative one of the one or more channels using the license-exempt band frequency.
The channel to be added to the secondary cell includes:
Wherein the channel utilization information is determined based on channel utilization information for each of the one or more channels.
Wherein the channel utilization ratio information includes:
Is measured based on the beacon signal transmitted by the wireless LAN access point,
Wherein the beacon signal comprises available bandwidth information.
The base station comprises:
A beacon signal including channel utilization information of a channel to be added to the secondary cell is periodically transmitted,
Wherein the one or more field values constituting the beacon signal are set to a maximum value.
The measurement report includes:
And channel utilization information for each of the one or more channels including the representative channel, and is transmitted to the primary cell.
Transmitting measurement configuration information for channel state measurement of a channel using a license-exempt band frequency to a terminal;
Receiving a measurement report including channel state measurement results for a representative one of the one or more channels using the license-exempt band frequency; And
Generating additional configuration information for a channel to be added to the terminal as a secondary cell among at least one channel using the license-exempt band frequency.
Wherein the measurement configuration information comprises:
And information about a representative one of the one or more channels using the license-exempt band frequency.
The channel to be added to the secondary cell includes:
Wherein the channel utilization information is determined based on channel utilization information for each of the one or more channels.
Wherein the channel utilization ratio information includes:
Is measured based on the beacon signal transmitted by the wireless LAN access point,
Wherein the beacon signal comprises available bandwidth information.
Further comprising periodically transmitting a beacon signal including channel utilization ratio information of a channel to be added to the secondary cell,
Wherein the one or more field values constituting the beacon signal are set to a maximum value.
The measurement report includes:
And channel utilization rate information for each of the one or more channels including the representative channel measured by the terminal.
A receiver for receiving measurement configuration information for channel state measurement of a channel using a license-exempt band frequency from a base station;
A transmitter configured to measure a channel state of a representative channel among at least one channel using the license-exempt band frequency based on the measurement configuration information, and transmit a measurement report including a channel state measurement result; And
And a control unit for receiving additional configuration information for a channel to be added as a secondary cell among at least one channel using the license-exempt band frequency from the base station, and further configuring the secondary cell.
Wherein the measurement configuration information comprises:
And information on a representative one of the one or more channels using the license-exempt band frequency.
The channel to be added to the secondary cell includes:
And determining channel utilization information for each of the at least one channel.
Wherein the channel utilization ratio information includes:
Is measured based on the beacon signal transmitted by the wireless LAN access point,
Wherein the beacon signal comprises available bandwidth information.
The base station comprises:
A beacon signal including channel utilization information of a channel to be added to the secondary cell is periodically transmitted,
Wherein the at least one field value constituting the beacon signal is set to a maximum value.
The measurement report includes:
And channel utilization information for each of the at least one channel including the representative channel, and is transmitted to the primary cell.
A transmitter for transmitting measurement configuration information for channel state measurement of a channel using the license-exempt band frequency to the terminal;
Receiving a measurement report including a channel state measurement result for a representative one of the at least one channel using the license-exempt band frequency; And
And a controller for generating additional configuration information for a channel to be added as a secondary cell to at least one of the one or more channels using the license-exempt band frequency.
Wherein the measurement configuration information comprises:
And information about a representative one of the one or more channels using the license-exempt band frequency.
The channel to be added to the secondary cell includes:
And determining channel utilization information for each of the at least one channel.
Wherein the channel utilization ratio information includes:
Is measured based on the beacon signal transmitted by the wireless LAN access point,
Wherein the beacon signal comprises available bandwidth information.
The transmitter may further comprise:
A beacon signal including channel utilization information of a channel to be added to the secondary cell is periodically transmitted,
Wherein the at least one field value constituting the beacon signal is set to a maximum value.
The measurement report includes:
And channel utilization information for each of the one or more channels including the representative channel measured by the terminal.
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