JP2015216471A - Communication method, and communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid visit of a user device to a cell in a time division duplex scheme dedicated to downlink, in a mobile communication system supporting carrier aggregation using a carrier of a time division duplex scheme dedicated to downlink.SOLUTION: In a communication method performed by a base station and a user device in a mobile communication system supporting carrier aggregation using a carrier of a time division duplex scheme dedicated to downlink, the base station includes a system information transmission step for notifying the system information including predetermined information, in a cell of the time division duplex scheme dedicated to downlink, and a cell selection control step where the user device having received the system information tries selection of a cell having a frequency different from the above-mentioned cell, based on the predetermined information.

Description

  The present invention relates to a mobile communication system, and particularly relates to cell selection (cell selection / cell reselection) of a user apparatus UE.

  In LTE-Advanced, in order to achieve a throughput that exceeds LTE while maintaining backward compatibility with LTE, a plurality of carriers are used simultaneously with a bandwidth (up to 20 MHz) supported by LTE as a basic unit. Carrier aggregation (CA) that performs communication is employed (see, for example, Non-Patent Document 1). A carrier that is a basic unit in carrier aggregation is called a component carrier (CC).

  When CA is performed, a PCell (Primary cell) that is a highly reliable cell that ensures connectivity and a SCell (Secondary cell) that is an ancillary cell are set for the user apparatus UE. First, the user apparatus UE can connect to the PCell and add an SCell as necessary. The PCell is a cell similar to a cell in the LTE system that supports RLM (Radio Link Monitoring), SPS (Semi-Persistent Scheduling), and the like.

  The SCell is a cell that is added to the PCell and set for the user apparatus UE. The addition and deletion of the SCell is performed by RRC (Radio Resource Control) signaling. Immediately after being set for the user apparatus UE, the SCell is in an inactive state (deactivate state). Therefore, the SCell is a cell that can communicate (schedulable) for the first time by being activated in the MAC (Media Access Control) layer. is there. The CC corresponding to the PCell is referred to as PCC (Primary Component Carrier), and the CC corresponding to the SCell is referred to as SCC (Secondary Component Carrier).

  In LTE, two duplex modes (Duplex mode) are defined, which are a Frequency Division Duplex (FDD) scheme and a Time Division Duplex (TDD) scheme. In the FDD scheme, uplink communication and downlink communication are executed in different frequency bands. In the TDD scheme, uplink communication and downlink communication use the same frequency band, and uplink communication and downlink communication are performed. Are separated by time. In addition, switching between the duplex modes can be performed by inter-frequency handover.

3GPP TS 36.300 V12.1.0 (2014-03)

  Regarding the CA and Duplex modes described in the background art above, LTE Rel. In 10-11, a plurality of CCs constituting a CA is limited to the same Duplex mode. That is, for example, in one form of CA as shown in FIG. 1, as shown in (a), a plurality of CCs (PCell, SCel) are all FDD, as shown in (b), a plurality of All CCs were limited to TDD.

  On the other hand, in Rel-12, it is considered to extend CA and perform CA using CCs of different Duplex modes. FIG. 2 shows a mode in which FDD is used for PCell (PCC) and TDD is used for SCell (SCC) as an example of CA using CCs in different Duplex modes. Hereinafter, CA using CCs of different Duplex modes will be described as FDD-TDD CA.

  In FDD-TDD CA as shown in FIG. 2, for example, frequency bands (2 GHz: FDD, 3.5 GHz: TDD) as shown in FIG. 3 are used. Moreover, although various configurations for UL / DL are defined in TDD, in FDD-TDD CA, as shown in FIGS. 4A and 4B, a configuration using configuration # 5 has been studied. ing.

  Furthermore, in FDD-TDD CA, the use of TDD DL only (DL-dedicated time division duplex system) configuration is also discussed. TDD DL only configuration is to set all subframes for DL communication in the TDD frequency band. Such a TDD frequency or cell is described as “TDD DL only”. FIG. 5 shows a configuration of FDD-TDD CA with “TDD DL only” as SCC. The purpose of adopting such a configuration is to ensure the maximum DL resource in the SCC and improve the Throughput.

  However, since the frequency band (band) of “TDD DL only” is a frequency band dedicated to DL, even if the user apparatus UE camps (located) in the cell of “TDD DL only”, uplink communication cannot be performed. Unable to communicate normally.

  The present invention has been made in view of the above points, and in a mobile communication system that supports carrier aggregation using a carrier of a downlink dedicated time division duplex scheme, the user apparatus is provided with a downlink dedicated time division duplex scheme. An object is to provide a technique for avoiding being in a cell.

According to an embodiment of the present invention, there is provided a communication method executed by a base station and a user apparatus in a mobile communication system that supports carrier aggregation using a carrier in a downlink dedicated time division duplex system,
A system information transmitting step in which the base station broadcasts system information including predetermined information in a downlink-only time division duplex cell;
There is provided a communication method including a cell selection control step in which the user apparatus that has received the system information tries to select a cell having a frequency different from the frequency of the cell based on the predetermined information.

Further, according to the embodiment of the present invention, there is provided a communication method executed by a base station and a user apparatus in a mobile communication system that supports carrier aggregation using a carrier of a downlink dedicated time division duplex method,
A system information transmission control step in which the base station does not broadcast predetermined system information broadcasted in a cell of a duplex scheme other than the downlink dedicated time division duplex scheme in a downlink dedicated time division duplex scheme;
A frequency different from the frequency of the downlink dedicated time division duplex cell based on the fact that the user equipment that has received the MIB in the downlink dedicated time division duplex scheme cell does not receive the predetermined system information. And a cell selection control step that attempts to select a cell.

Further, according to the embodiment of the present invention, there is provided a communication method executed by a base station and a user apparatus in a mobile communication system that supports carrier aggregation using a carrier of a downlink dedicated time division duplex method,
A system information transmission step in which the base station broadcasts system information including predetermined information in a cell where the user apparatus is located;
A cell selection control step in which, when the user apparatus that has received the system information selects a neighboring cell having a frequency different from the frequency of the cell, the neighboring cell having a frequency included in the predetermined information is not selected; A communication method is provided.

  According to an embodiment of the present invention, in a mobile communication system that supports carrier aggregation using a downlink-only time division duplex carrier, the user apparatus is located in a downlink-only time division duplex cell. You can avoid that.

It is a figure which shows the example of CA which uses the same Duplex mode by multiple CC. It is a figure which shows the example of CA which uses different Duplex mode in multiple CC. It is a figure which shows the example of the frequency band in FDD-TDD CA. It is a figure which shows the example of the combination of Duplex mode in SCC and PCC. It is a figure which shows the example of the combination of Duplex mode in SCC and PCC. It is a block diagram of the communication system which concerns on embodiment of this invention. It is a figure for demonstrating the concept of the process in 1st Embodiment. It is a sequence diagram for demonstrating the operation example 1 of the communication system in 1st Embodiment. It is a figure which shows the example of the content of MIB in 1st Embodiment. It is a sequence diagram for demonstrating the operation example 2 of the communication system in 1st Embodiment. It is a figure for demonstrating the outline | summary of the process in 2nd Embodiment. It is a figure for demonstrating the outline | summary of the process in 2nd Embodiment. It is a sequence diagram for demonstrating the operation example of the communication system in 2nd Embodiment. It is a figure which shows the example of IE of SIB5 in 2nd Embodiment. It is a figure for demonstrating the example of IE of SIB5 in 2nd Embodiment. It is a block diagram of the user apparatus UE. It is a block diagram of the base station eNB.

  Embodiments of the present invention will be described below with reference to the drawings. The embodiment described below is only an example, and the embodiment to which the present invention is applied is not limited to the following embodiment. Further, although the present embodiment is directed to an LTE mobile communication system, the present invention is not limited to LTE and can be applied to other mobile communication systems. In the present specification and claims, unless otherwise specified, the term “LTE” is used to mean 3GPP Rel-12 or Rel-12 or later.

  In the present application, unless otherwise specified, “cell selection” is used to include both cell selection and cell selection in LTE. Both are for selecting cells.

  In addition, the user apparatus UE completes cell selection (cell selection / reselection) processing and the user apparatus UE selects (determines) a cell for monitoring system information and paging information. It is to become a state. “Camping a cell” may be rephrased as “residing in a cell”.

(Overall system configuration)
FIG. 6 shows a configuration diagram of a communication system in the embodiment of the present invention (common to the first and second embodiments). As shown in FIG. 6, the communication system in the present embodiment is a system including a base station eNB and a user apparatus UE. In FIG. 6, one base station eNB and one user apparatus UE are shown, but this is for the convenience of illustration, and there may be a plurality of each.

  In the example of FIG. 6, the base station eNB itself has a radio unit, and the radio unit is also installed at a location away from the base station eNB. The said radio | wireless part is a part of base station eNB, and is connected with the base station eNB, for example with an optical fiber. Such a remote radio unit may be called RRH (Remote Radio Head). In this Embodiment, CA is possible because base station eNB forms PCell and RRH forms SCell by base station eNB.

  For example, as in the case illustrated in FIG. 2, the base station eNB forms an FDD PCell, and the RRH forms an “SDD DL only” SCell. However, as described above, it is necessary to prevent the user apparatus UE in the RRC IDLE state from being located in a cell of “TDD DL only” (a cell that is not a CA SCell). The second embodiment and the second embodiment will be described.

(First embodiment)
FIG. 7 is a diagram for explaining the concept of processing in the first embodiment. As shown in FIG. 7, in the first embodiment, the user apparatus UE receives an MIB (Master Information Block) which is the most basic system information (broadcast information) in a “TDD DL only” cell, Based on the information in the MIB, the “TDD DL only” cell is not camp.

  In the present embodiment, information indicating whether the user apparatus UE can access the cell (whether it can be camp) is included in the MIB transmitted from the base station eNB forming the cell, and “TDD Information (barred) indicating that the user apparatus UE cannot access the cell is included in the MIB transmitted by the base station eNB that has set the cell of “DL only” in the cell.

  FIG. 8 shows an operation example 1 of the communication system according to the first embodiment. FIG. 8 shows a cell search operation when the user apparatus UE is powered on. In FIG. 8, the base station eNB forms a “TDD DL only” cell using RRH, and the base station eNB The signal transmitted from is a signal of a “TDD DL only” cell. Further, in FIG. 8, each signal transmitted from the base station eNB is periodically transmitted. In FIG. 8, a signal flow focusing on the reception operation of the user apparatus UE is illustrated.

  In step 101, the user apparatus UE receives a synchronization signal (PSS / SSS) from the base station eNB, thereby synchronizing the timing and acquiring a cell ID (PCI). The user apparatus UE receives the reference signal transmitted from the base station eNB to the cell synchronized by the synchronization signal, and measures the received power (step 102). The reference signal uses a code corresponding to PCI one-to-one, and can be separated from other cells by correlating with the code. Steps 101 and 102 may be performed in a plurality of cells, but FIG. 8 shows only the “TDD DL only” cell.

  In step 103, the cell (best cell) having the highest received power of the reference signal is selected. In the example of FIG. 8, the “TDD DL only” cell is selected. In step 104, the user apparatus UE receives MIB transmitted by PBCH in the cell. The MIB includes a DL system bandwidth, the number of transmission antennas, a system frame number (SFN), and the like. In this embodiment, in addition to these, information indicating whether or not the cell can be accessed (barred indication) ) Is included. That is, the base station eNB transmits the MIB including barred indication in the MIB.

  In a normal operation when an MIB not including barred indication is received, the user apparatus UE receives SIB1 (System Information Block Type1), and the cell selected as the best cell based on SIB1 is a cell that can be camped. Judgment is made based on a predetermined evaluation standard. As a result of the determination, if the cell is not campable and the selection of another cell of the same frequency is allowed (allowed) by intraFreqReselection in SIB1, the selection process of the other cell of the same frequency is performed.

  On the other hand, in the present embodiment, the user equipment UE detects that the “TDD DL only” cell is a barred cell (a cell that cannot be camp) based on the MIB received in step 104 of FIG. 8, and does not read SIB1. An attempt is made to select a cell of another frequency (which may be referred to as a frequency band or a frequency band) (step 105). Since SIB1 is not read, it cannot be determined by intraFreqReselection that selection of other cells of the same frequency is allowed, and cells of other frequencies are selected. Or the user apparatus UE may try selection of the cell of another frequency, without performing determination by intraFreqReselection at the time of detecting barred. Attempting to select a cell of another frequency includes, for example, receiving a synchronization signal of another frequency, measuring received power, and selecting the best cell.

  With reference to FIG. 9, the example of MIB in this Embodiment is demonstrated. FIG. 9A shows a conventional MIB, and FIG. 9B shows an example of the MIB in the present embodiment. The underline is for showing the information of interest in an easy-to-understand manner. As shown in FIG. 9B, “accessInfo” is added. The description of “accessInfo” is as shown in FIG. 9C, and as described in FIG. 9C, “accessInfo” is “specifies whether or not the UE can access the cell”. Yes, “a value of 1 in the first bit indicates that access to the cell is prohibited”. In this way, being barred can be represented by 1 bit, for example.

  In the above example, the barred information is included in the MIB, but instead of the barred information, information indicating that the target cell (the cell to which the MIB is transmitted) is a “TDD DL only” cell (“TDD DL only”). "Referred to as cell information). Similar to the barred information, the user apparatus UE that has received the MIB including the “TDD DL only” cell information detects that the cell is not a camp-capable cell, and does not read the SIB1 to another frequency (frequency The operation of trying to select a cell in a band or a frequency band may be performed.

  In the above example, barred information or “TDD DL only” cell information is included in the MIB, but without changing to such MIB, the user apparatus UE can be camp to the “TDD DL only” cell. It is also possible not to let An example of this case will be described as an operation example 2 with reference to FIG.

  10, steps 101 to 103 are the same as those in FIG. In Step 104 of FIG. 10, the base station eNB transmits an MIB that does not include barred indication, and the user apparatus UE receives the MIB. However, in the operation example 2, the base station eNB does not transmit SIB1 in the “TDD DL only” cell. Since the user apparatus UE does not receive SIB1, it cannot be determined by intraFreqReselection that selection of other cells of the same frequency is permitted, and therefore attempts to select cells of other frequencies (step 105). Note that the user apparatus UE may attempt to select a cell of another frequency without performing a determination based on intraFreqReselection when detecting that the SIB1 is not received. Further, the base station eNB transmits SIB1 in cells other than “TDD DL only”.

(Second Embodiment)
FIGS. 11 and 12 are diagrams for explaining the outline of the processing according to the second embodiment. As shown in FIG. 11, in the second embodiment, in a state where the user apparatus UE has already camps on the cell 1 (UL / DL cell of FDD or TDD), the cell 1 Instead of selecting (camping) cell 2 (frequency different from the frequency of cell 1), which is a “TDD DL only” cell, is avoided. For this reason, information indicating that the cell of the frequency of the cell 2 is not to be selected is included in the SIB5 (System Information Block Type 5) transmitted in the cell 1 that is camp.

  The SIB5 includes information on peripheral frequency that is a measurement target, etc. In this embodiment, in addition to these, the cell having the frequency of the cell 2 is not selected. Information is included. Since this information is a list of frequencies to be excluded, it may be referred to as a “frequency black list”.

  With reference to FIG. 12, the outline of the processing in the second embodiment will be described more specifically. In the example of FIG. 12, the base station eNB1 forms a cell 1 (FDD or TDD UL / DL), and the user apparatus UE1 camps on the cell 1. In addition, as adjacent cells, the base station eNB2 (and RRH) forms the cell 2 (TDD DL only) and the cell 3 (FDD or TDD UL / DL), and the user apparatus UE2 includes the cell 2 (SCell) and the cell CA is implemented by 3 (PCell).

  At this time, the user apparatus UE1 receives from the base station eNB1 the SIB5 including information instructing not to select the cell having the frequency of the cell 2. Here, as a normal operation of a user equipment that is camping on a certain cell (serving cell), when the reception power of the cell becomes equal to or lower than a predetermined value or the like, based on the information of SIB5, There is an operation of measuring a cell and attempting to select (camp) the cell instead of the current cell.

  On the other hand, in the present embodiment, since the frequency of the cell 2 is excluded from the selection target by the SIB5, the user apparatus UE1 that has received the SIB5 uses “TDD DL only” when measuring the neighboring cells. Do not measure the frequency to be used. Therefore, it can exclude that user apparatus UE1 camps on a "TDD DL only" cell.

  In addition, in the example of FIG. 12, the base station eNB2 also transmits SIB5 including a frequency blacklist that excludes camp to the frequency of the “TDD DL only” cell, and the user apparatus UE2 that has received the SIB5 receives “ Avoid using "TDD DL only" cell as PCell.

  FIG. 13 is a sequence diagram illustrating an operation example of the communication system according to the second embodiment. In FIG. 13, the user apparatus UE has camp on the cell of the base station eNB-A, and receives SIB5 from the base station eNB-A (step 201). The SIB5 includes a frequency black list.

  Here, in the user apparatus UE, it is assumed that a search for neighboring cells of different frequencies (synchronization signal reception, reception power measurement, etc.) is started, for example, when the reception power of the cell of the base station eNB-A falls below a threshold value. The base station eNB-C that forms the “TDD DL only” cell transmits a synchronization signal and a reference signal in the cell, but the user apparatus UE uses the frequency blacklist to determine the frequency of the “TDD DL only” cell. Therefore, in step 202, the user apparatus UE does not measure the “TDD DL only” cell.

  On the other hand, the base station eNB-B forms a cell with a carrier having a frequency that is not in the frequency black list, and the user apparatus UE performs measurement of the cell (step 203). Thereby, if the predetermined condition is satisfied, the user apparatus UE performs the camping on the cell of the base station eNB-B instead of the current cell.

  FIG. 14 shows an example of SIB5 (System Information Block Type 5 information element) in the present embodiment. In FIG. 14, the underlined portion is different from the conventional SIB5. As shown in FIG. 14, “interFreq CarrierBlackList” is added. ARFCN shown in FIG. 14 is a frequency identification number. FIG. 15 also describes “interFreqCarrierBlackList”.

(Device configuration)
<User device UE>
FIG. 16 shows a functional configuration diagram of the user apparatus UE in the embodiment (first and second embodiments) of the present invention. As illustrated in FIG. 16, the user apparatus UE includes a DL signal reception unit 101, a UL signal transmission unit 102, a cell selection control unit 103, and a CA control unit 105. Note that FIG. 16 shows only functional units that are particularly relevant to the present invention in the user apparatus UE, and the user apparatus UE also has a function (not shown) for performing an operation based on at least LTE.

  The DL signal receiving unit 101 includes a function of receiving various downlink signals from the base station eNB and acquiring higher layer information from the received physical layer signal, and the UL signal transmitting unit 102 receives from the user apparatus UE It includes a function of generating various signals of the physical layer from information of higher layers to be transmitted and transmitting the signals to the base station eNB. Further, the DL signal receiving unit 101 and the UL signal transmitting unit 102 also have a function of performing communication by CA using a plurality of CCs.

  The CA control unit 104 relates to CA in the user apparatus UE such as management of PCell (PCC) and SCell (SCC) constituting the CA, addition / deletion of SCell based on an instruction from the base station eNB, and activation / deactivation. Take control.

  The cell selection control unit 103 performs the control related to cell selection described in the first and second embodiments. For example, in the case of the operation example 1 in the first embodiment, the cell selection control unit 103 checks Barred indication or “TDD DL only” cell information included in the MIB received from the base station eNB, and is Barred. Related to the MIB, for example, the predetermined bit is 1 or the like, or the “TDD DL only” cell information indicates that the cell is a “TDD DL only” cell. The cell is determined to be a cell that cannot be camp, and an attempt is made to select a cell having a frequency different from the frequency of the cell. Further, in the operation example 2 in the first embodiment, the cell selection control unit 103 finds a candidate cell for the camp by cell search and receives the MIB, but if the SIB1 is not received, the cell selection control unit 103 sets the cell as barred. Therefore, it is determined that the cell is a cell that cannot be camp, and an attempt is made to select a cell having a frequency different from the frequency of the cell. Note that, regarding the determination of not receiving SIB1, if SIB1 is not received even after waiting for a predetermined period, it can be determined that SIB1 is not received.

  Further, in the second embodiment, the cell selection control unit 103 confirms the frequency placed on the frequency blacklist included in the SIB5 received from the base station eNB, and uses the frequency as an inter-frequency (inter frequency) cell. Excluded from selection candidates. Excluding from selection candidates means that the search for the synchronization signal of the cell of the frequency is not performed, the synchronization signal is searched, the reception power is not measured, the reception power is measured, but the selection is not performed. There may be.

<Base station eNB>
FIG. 17 shows a functional configuration diagram of the base station eNB in the embodiments (first and second embodiments) of the present invention. As illustrated in FIG. 17, the base station eNB includes a DL signal transmission unit 201, a UL signal reception unit 202, a system information transmission control unit 203, and a CA control unit 204. FIG. 17 shows only functional units that are particularly related to the embodiment of the present invention in the base station eNB, and the base station eNB also has a function (not shown) for performing at least the operation based on the LTE scheme. Is.

  The DL signal transmission unit 201 includes a function of generating and transmitting various physical layer signals from upper layer information to be transmitted from the base station eNB. The UL signal receiving unit 202 includes a function of receiving various uplink signals from the user apparatus UE and acquiring higher layer information from the received physical layer signals. In addition, the DL signal transmission unit 201 and the UL signal reception unit 202 also have a function of performing communication by CA using a plurality of CCs. In particular, the DL signal transmission unit 201 can perform DL communication using “TDD DL only” configuration (eg, SCC in FIG. 5).

  The CA control unit 204 performs control related to CA such as management of PCell (PCC) and SCell (SCC) constituting the CA, addition / deletion of SCell, and activation / deactivation for each user apparatus UE.

  The system information transmission control unit 203 performs transmission control of the system information (MIB, SIB) described in the first and second embodiments.

  For example, in the first operation example according to the first embodiment, the system information transmission control unit 203 uses a CC (cell) of “TDD DL only” to transmit an MIB including Barred indication or “TDD DL only” cell information as a DL signal. It transmits via the transmission part 201. Moreover, in the operation example 2 in the first embodiment, the system information transmission control unit 203 does not transmit SIB1 in the CC (cell) of “TDD DL only”. In these operations, for example, the CA control unit 204 notifies the system information transmission control unit 203 that the “TDD DL only” cell has been set, and based on the notification, the system information transmission control unit 203 Transmission control, control not transmitting SIB1, and the like are performed.

  Further, in the second embodiment, the system information transmission control unit 203 uses “TDD DL only” in a normal cell (eg, a cell composed of FDD or TDD DL / UL) that is not “TDD DL only”. The SIB 5 including the frequency black list in which the frequency is set is transmitted via the DL signal transmission unit 201.

  Note that the functional configuration of the communication system including the base station eNB and the user apparatus UE is not limited to the configuration including the base station eNB and the user apparatus UE, and any function that can realize the processing described in the present embodiment. A configuration may be adopted. For example, the communication system is a communication system including a base station and a user apparatus that are used in a mobile communication system that supports carrier aggregation using a carrier of a downlink-only time division duplex method, A downlink dedicated time-division duplex cell comprising system information transmitting means for broadcasting system information including predetermined information, wherein the user apparatus receives the system information and based on the predetermined information, The communication system includes cell selection control means that attempts to select a cell having a frequency different from the frequency of the cell. With this configuration, in a mobile communication system that supports carrier aggregation using a downlink-only time-division duplex carrier, it is possible to prevent the user apparatus from being located in a downlink-only time-division duplex cell. it can.

  The system information is, for example, an MIB, and the predetermined information is information indicating that a service area in the downlink dedicated time division duplex system cell is prohibited. The predetermined information may be information indicating that a cell to which the MIB is transmitted is a downlink-only time division duplex cell. In these configurations, since the MIB is used, it is possible to avoid the presence of the downlink dedicated time division duplex cell in the initial stage of the cell selection process, and the user apparatus can efficiently select another frequency cell. Can be made.

  Further, the communication system of the present embodiment is a communication system including a base station and a user apparatus that are used in a mobile communication system that supports carrier aggregation using a carrier in a downlink dedicated time division duplex system, The base station performs control so as not to broadcast predetermined system information broadcast in a cell with a duplex scheme other than the downlink dedicated time division duplex scheme in a downlink dedicated time division duplex scheme cell. Transmission control means, wherein the user equipment receives the MIB in the downlink dedicated time division duplex system cell and then does not receive the predetermined system information, based on the downlink dedicated time division duplex You may comprise as a communication system provided with the cell selection control means which tries to select the cell of the frequency different from the frequency of the cell of a system. With this configuration, in a mobile communication system that supports carrier aggregation using a downlink-only time-division duplex carrier, it is possible to prevent the user apparatus from being located in a downlink-only time-division duplex cell. it can.

  The predetermined system information is, for example, SIB1. This configuration has an advantage of being easy to implement because it is only necessary to prevent SIB1 from being transmitted in a downlink time division duplex cell.

  Further, the communication system of the present embodiment is a communication system including a base station and a user apparatus that are used in a mobile communication system that supports carrier aggregation using a carrier in a downlink dedicated time division duplex system, The base station includes system information transmitting means for broadcasting system information including predetermined information in a cell where the user apparatus is located, and the user apparatus receives the system information and is different from a frequency of the cell. In the case of selecting a frequency neighboring cell, the communication system may include a cell selection control unit that does not select a frequency neighboring cell included in the predetermined information. With this configuration, in a mobile communication system that supports carrier aggregation using a downlink-only time-division duplex carrier, it is possible to prevent the user apparatus from being located in a downlink-only time-division duplex cell. it can.

  The system information is, for example, SIB5, and the predetermined information is a black list having a frequency different from the frequency of the cell where the user apparatus is located. Since the frequency blacklist is used in this way, the base station eNB can flexibly specify a frequency that the user apparatus does not want to access.

  The functional configuration of the user apparatus / base station described in the present embodiment may be realized by executing a program by a CPU (processor) in the user apparatus / base station including a CPU and a memory. In addition, a configuration realized by hardware such as a hardware circuit including processing logic described in this embodiment may be used, or a program and hardware may be mixed.

  Although the embodiments of the present invention have been described above, the disclosed invention is not limited to such embodiments, and those skilled in the art will understand various variations, modifications, alternatives, substitutions, and the like. I will. Although specific numerical examples have been described in order to facilitate understanding of the invention, these numerical values are merely examples and any appropriate values may be used unless otherwise specified. The classification of items in the above description is not essential to the present invention, and the items described in two or more items may be used in combination as necessary, or the items described in one item may be used in different items. It may be applied to the matters described in (if not inconsistent). The boundaries between functional units or processing units in the functional block diagram do not necessarily correspond to physical component boundaries. The operations of a plurality of functional units may be physically performed by one component, or the operations of one functional unit may be physically performed by a plurality of components. For convenience of explanation, the user apparatus and the base station have been described using functional block diagrams, but such an apparatus may be realized in hardware, software, or a combination thereof. Software operated by a processor included in a user apparatus and software operated by a processor included in a base station according to the embodiment of the present invention are random access memory (RAM), flash memory, read-only memory (ROM), EPROM, and EEPROM. , A register, a hard disk (HDD), a removable disk, a CD-ROM, a database, a server, or any other suitable storage medium. The present invention is not limited to the above embodiments, and various modifications, modifications, alternatives, substitutions, and the like are included in the present invention without departing from the spirit of the present invention.

eNB base station UE user apparatus 101 DL signal reception unit 102 UL signal transmission unit 103 cell selection control unit 104 CA control unit 201 DL signal transmission unit 202 UL signal reception unit 203 system information transmission control unit 204 CA control unit

Claims (10)

A communication method executed by a base station and a user apparatus in a mobile communication system that supports carrier aggregation using a carrier in a downlink-only time division duplex system,
A system information transmitting step in which the base station broadcasts system information including predetermined information in a downlink-only time division duplex cell;
The communication method comprising: a cell selection control step in which the user apparatus that has received the system information attempts to select a cell having a frequency different from the frequency of the cell based on the predetermined information. 2. The system information according to claim 1, wherein the system information is an MIB, and the predetermined information is information indicating that presence in a cell of the downlink dedicated time division duplex system is prohibited. The communication method described. The system information is an MIB, and the predetermined information is information indicating that a cell to which the MIB is transmitted is a cell of the downlink dedicated time division duplex system. The communication method according to 1. A communication method executed by a base station and a user apparatus in a mobile communication system that supports carrier aggregation using a carrier in a downlink-only time division duplex system,
A system information transmission control step in which the base station does not broadcast predetermined system information broadcasted in a cell of a duplex scheme other than the downlink dedicated time division duplex scheme in a downlink dedicated time division duplex scheme;
A frequency different from the frequency of the downlink dedicated time division duplex cell based on the fact that the user equipment that has received the MIB in the downlink dedicated time division duplex scheme cell does not receive the predetermined system information. And a cell selection control step for attempting to select a cell.   The communication method according to claim 4, wherein the predetermined system information is SIB1. A communication method executed by a base station and a user apparatus in a mobile communication system that supports carrier aggregation using a carrier in a downlink-only time division duplex system,
A system information transmission step in which the base station broadcasts system information including predetermined information in a cell where the user apparatus is located;
A cell selection control step in which, when the user apparatus that has received the system information selects a neighboring cell having a frequency different from the frequency of the cell, the neighboring cell having a frequency included in the predetermined information is not selected; A communication method comprising: The communication method according to claim 6, wherein the system information is SIB5, and the predetermined information is a black list having a frequency different from a frequency of a cell where the user apparatus is located. A communication system comprising a base station and a user apparatus used in a mobile communication system that supports carrier aggregation using a carrier of a downlink dedicated time division duplex system,
The base station includes a system information transmission unit that broadcasts system information including predetermined information in a downlink-only time division duplex cell.
The user apparatus includes a cell selection control unit that receives the system information and attempts to select a cell having a frequency different from the frequency of the cell based on the predetermined information. A communication system comprising a base station and a user apparatus used in a mobile communication system that supports carrier aggregation using a carrier of a downlink dedicated time division duplex system,
The base station performs control so as not to broadcast predetermined system information broadcast in a cell with a duplex scheme other than the downlink dedicated time division duplex scheme in a downlink dedicated time division duplex scheme cell. A transmission control means;
The user equipment receives the MIB in the downlink dedicated time division duplex cell and then does not receive the predetermined system information based on the downlink dedicated time division duplex cell frequency and A communication system comprising cell selection control means for attempting to select cells of different frequencies. A communication system comprising a base station and a user apparatus used in a mobile communication system that supports carrier aggregation using a carrier of a downlink dedicated time division duplex system,
The base station includes system information transmission means for broadcasting system information including predetermined information in a cell where the user apparatus is located,
When the user apparatus receives the system information and selects a neighboring cell having a frequency different from the frequency of the cell, cell selection control means that does not select a neighboring cell having a frequency included in the predetermined information. A communication system comprising: