WO2014181831A1

WO2014181831A1 - User terminal and processor

Info

Publication number: WO2014181831A1
Application number: PCT/JP2014/062370
Authority: WO
Inventors: 優志長坂; 真人藤代; 空悟守田; 智春山▲崎▼; 裕之安達
Original assignee: 京セラ株式会社
Priority date: 2013-05-10
Filing date: 2014-05-08
Publication date: 2014-11-13
Also published as: JP2014220778A

Abstract

User equipment (UE) (100), which supports cellular communication and WLAN communication, stores an identifier associated with the UE (100). The UE (100) receives, from an evolved Node B (eNB) (200), connection control information for randomly selecting a UE (100) which is permitted to connect with an access point (AP) (300). The UE (100) performs control such that a connection with the AP (300) is not established if the identifier does not satisfy connection permission conditions defined by the control connection information.

Description

User terminal and processor

The present invention relates to a user terminal and a processor used in a cellular communication system capable of cooperating with a wireless LAN system (WLAN system).

In recent years, user terminals (so-called dual terminals) having a cellular communication unit and a WLAN communication unit are becoming popular. In addition, the number of WLAN access points (hereinafter simply referred to as “access points”) managed by operators of cellular communication systems is increasing.

Therefore, in 3GPP (3rd Generation Partnership Project), which is a standardization project for cellular communication systems, a technique that can strengthen the cooperation between the cellular communication system and the WLAN system is planned to be studied (see Non-Patent Document 1).

One of the purposes of such technology is to balance the load level at the cellular base station and the access point by improving the usage rate of the access point.

It is assumed that the user terminal compares the communication status of the cellular base station and the access point, and the user terminal can select the connection destination from the cellular base station and the access point.

In this case, a plurality of user terminals can select the same access point as a connection destination and start connection processing for the access points all at once. Therefore, there may be a user terminal that cannot establish a connection with an access point due to a conflict in connection processing.

Even if all of these user terminals can establish a connection with an access point, the load level of the access point increases, so that sufficient throughput cannot be ensured or the unused resources of the cellular base station are excessive. There is a problem.

Therefore, an object of the present invention is to solve a problem caused by a plurality of user terminals connecting to the same access point all at once.

The user terminal according to the first feature supports cellular communication and WLAN communication. The user terminal receives from the cellular base station, a storage unit that stores an identifier associated with the user terminal, and connection control information for randomly selecting a user terminal that is allowed to connect to the access point. And a control unit that controls not to establish a connection with the access point when the identifier does not satisfy a connection permission condition defined by the connection control information.

The user terminal according to the second feature supports cellular communication and WLAN communication. The user terminal includes a control unit that delays a start timing for starting connection with the access point according to a random number when it is determined to start connection with the access point.

According to the present invention, it is possible to solve problems caused by a plurality of user terminals connecting to the same access point all at once.

It is a system configuration figure concerning a 1st embodiment and a 2nd embodiment. It is a block diagram of UE (user terminal) concerning a 1st embodiment and a 2nd embodiment. It is a block diagram of eNB (cellular base station) which concerns on 1st Embodiment and 2nd Embodiment. It is a block diagram of AP (access point) which concerns on 1st Embodiment and 2nd Embodiment. It is a protocol stack figure of the radio | wireless interface in a LTE system. It is a block diagram of the radio | wireless frame used with a LTE system. It is a figure for demonstrating the operating environment which concerns on 1st Embodiment and 2nd Embodiment. It is an operation | movement sequence diagram which concerns on 1st Embodiment. It is an operation | movement flowchart of UE which concerns on 1st Embodiment. It is an operation | movement sequence diagram which concerns on 2nd Embodiment. It is a figure which shows the specific example of the timer information table which concerns on 2nd Embodiment. It is an operation | movement flowchart of UE which concerns on 2nd Embodiment.

[Outline of Embodiment]
The user terminal according to the first embodiment supports cellular communication and WLAN communication. The user terminal receives from the cellular base station, a storage unit that stores an identifier associated with the user terminal, and connection control information for randomly selecting a user terminal that is allowed to connect to the access point. And a control unit that controls not to establish a connection with the access point when the identifier does not satisfy a connection permission condition defined by the connection control information.

In the first embodiment, the connection control information is set based on the load level of the cellular base station.

In the first embodiment, the connection control information is set such that the higher the load level of the cellular base station, the higher the probability that connection with the access point is permitted.

In the first embodiment, the connection control information includes a first value and a second value, and the control unit calculates a result of calculating the identifier and the first value that matches the second value. If not, control is performed so as not to establish a connection with the access point.

The processor according to the first embodiment is provided in a user terminal that supports cellular communication and WLAN communication. The processor receives, from a cellular base station, connection control information for randomly selecting a user terminal that is allowed to connect to an access point, and a connection permission condition defined by the connection control information. And controlling to not establish a connection with the access point when the identifier associated with is not satisfied.

The user terminal according to the second embodiment supports cellular communication and WLAN communication. The user terminal includes a control unit that delays a start timing for starting connection with the access point according to a random number when it is determined to start connection with the access point.

In the second embodiment, the control unit acquires information indicating the load level of the access point during the waiting time until the start timing. When the acquired load level exceeds a threshold value, the control unit stops connection with the access point.

The second embodiment further includes a storage unit that stores a table in which waiting times are associated with each predetermined numerical range. The control unit specifies the waiting time corresponding to a numerical range to which the random number belongs based on the table. The control unit determines the start timing from the specified waiting time.

In the second embodiment, the table is set from a cellular base station.

The processor according to the second embodiment is provided in a user terminal that supports cellular communication and WLAN communication. When the processor determines to start the connection with the access point, the processor delays the start timing for starting the connection with the access point according to the random number.

[First Embodiment]
Hereinafter, an embodiment in the case where a cellular communication system (LTE system) configured in conformity with the 3GPP standard is linked with a wireless LAN (WLAN) system will be described with reference to the drawings.

(System configuration)
FIG. 1 is a system configuration diagram according to the embodiment. As shown in FIG. 1, the cellular communication system includes a plurality of UEs (User Equipment) 100, an E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network) 10, and an EPC (Evolved Packet Core) 20. The E-UTRAN 10 corresponds to a radio access network. The EPC 20 corresponds to a core network.

The UE 100 is a mobile radio communication device, and performs radio communication with a cell that has established a connection. UE100 is corresponded to a user terminal. The UE 100 is a terminal (dual terminal) that supports both cellular communication and WLAN communication methods.

The E-UTRAN 10 includes a plurality of eNBs 200 (evolved Node-B). The eNB 200 corresponds to a cellular base station. The eNB 200 manages one or a plurality of cells, and performs radio communication with the UE 100 that has established a connection with the own cell. Note that “cell” is used as a term indicating a minimum unit of a radio communication area, and is also used as a term indicating a function of performing radio communication with the UE 100. The eNB 200 has, for example, a radio resource management (RRM) function, a user data routing function, and a measurement control function for mobility control and scheduling.

The eNB 200 is connected to each other via the X2 interface. The eNB 200 is connected to the MME / S-GW 500 included in the EPC 20 via the S1 interface.

The EPC 20 includes a plurality of MME (Mobility Management Entity) / S-GW (Serving-Gateway) 500. The MME is a network node that performs various types of mobility control for the UE 100, and corresponds to a control station. The S-GW is a network node that performs transfer control of user data, and corresponds to an exchange.

The WLAN system includes a WLAN access point (hereinafter referred to as “AP”) 300. The WLAN system is configured in accordance with, for example, IEEE 802.11 standards. The AP 300 communicates with the UE 100 in a frequency band (WLAN frequency band) different from the cellular frequency band. The AP 300 is connected to the EPC 20 via a router or the like.

Also, the eNB 200 and the AP 300 are not limited to being individually arranged, and the eNB 200 and the AP 300 may be arranged at the same location (Collocated). As one form of Collated, the eNB 200 and the AP 300 may be directly connected by an arbitrary interface of the operator.

Next, configurations of the UE 100, the eNB 200, and the AP 300 will be described.

FIG. 2 is a block diagram of the UE 100. As shown in FIG. 2, the UE 100 includes

antennas

101 and 102, a cellular communication unit 111, a WLAN communication unit 112, a user interface 120, a GNSS (Global Navigation Satellite System) receiver 130, a battery 140, and a memory. 150 and a processor 160. The memory 150 and the processor 160 constitute a control unit. The UE 100 may not have the GNSS receiver 130. Further, the memory 150 may be integrated with the processor 160, and this set (that is, a chip set) may be used as the processor 160 '.

The antenna 101 and the cellular communication unit 111 are used for transmitting and receiving cellular radio signals. The cellular communication unit 111 converts the baseband signal output from the processor 160 into a cellular radio signal and transmits it from the antenna 101. In addition, the cellular communication unit 111 converts a cellular radio signal received by the antenna 101 into a baseband signal and outputs it to the processor 160.

The antenna 102 and the WLAN communication unit 112 are used for transmitting and receiving WLAN radio signals. The WLAN communication unit 112 converts the baseband signal output from the processor 160 into a WLAN radio signal and transmits it from the antenna 102. In addition, the WLAN communication unit 112 converts the WLAN radio signal received by the antenna 102 into a baseband signal and outputs the baseband signal to the processor 160.

The user interface 120 is an interface with a user who owns the UE 100, and includes, for example, a display, a microphone, a speaker, and various buttons. The user interface 120 receives an input from the user and outputs a signal indicating the content of the input to the processor 160. The GNSS receiver 130 receives a GNSS signal and outputs the received signal to the processor 160 in order to obtain position information indicating the geographical position of the UE 100. The battery 140 stores power to be supplied to each block of the UE 100.

The memory 150 stores a program executed by the processor 160 and information used for processing by the processor 160. The processor 160 includes a baseband processor that performs modulation / demodulation and encoding / decoding of a baseband signal, and a CPU that executes programs stored in the memory 150 and performs various processes. The processor 160 may further include a codec that performs encoding / decoding of an audio / video signal. The processor 160 executes various processes and various communication protocols described later.

FIG. 3 is a block diagram of the eNB 200. As illustrated in FIG. 3, the eNB 200 includes an antenna 201, a cellular communication unit 210, a network interface 220, a memory 230, and a processor 240. The memory 230 and the processor 240 constitute a control unit.

The antenna 201 and the cellular communication unit 210 are used for transmitting and receiving cellular radio signals. The cellular communication unit 210 converts the baseband signal output from the processor 240 into a cellular radio signal and transmits it from the antenna 201. In addition, the cellular communication unit 210 converts a cellular radio signal received by the antenna 201 into a baseband signal and outputs it to the processor 240.

The network interface 220 is connected to the neighboring eNB 200 via the X2 interface and is connected to the MME / S-GW 500 via the S1 interface. The network interface 220 is used for communication with the AP 300 via the EPC 20.

The memory 230 stores a program executed by the processor 240 and information used for processing by the processor 240. The processor 240 includes a baseband processor that performs modulation / demodulation and encoding / decoding of a baseband signal, and a CPU that executes a program stored in the memory 230 and performs various processes. The processor 240 executes various processes and various communication protocols described later.

FIG. 4 is a block diagram of the AP 300. As illustrated in FIG. 4, the AP 300 includes an antenna 301, a WLAN communication unit 311, a network interface 320, a memory 330, and a processor 340.

The antenna 301 and the WLAN communication unit 311 are used for transmitting and receiving WLAN radio signals. The WLAN communication unit 311 converts the baseband signal output from the processor 340 into a WLAN radio signal and transmits it from the antenna 301. In addition, the WLAN communication unit 311 converts the WLAN radio signal received by the antenna 301 into a baseband signal and outputs the baseband signal to the processor 340.

The network interface 320 is connected to the EPC 20 via a router or the like. The network interface 320 is used for communication with the eNB 200 via the EPC 20.

The memory 330 stores a program executed by the processor 340 and information used for processing by the processor 340. The processor 340 includes a baseband processor that performs modulation / demodulation and encoding / decoding of the baseband signal, and a CPU that executes programs stored in the memory 330 and performs various processes.

FIG. 5 is a protocol stack diagram of a radio interface in the cellular communication system. As shown in FIG. 5, the radio interface protocol is divided into layers 1 to 3 of the OSI reference model, and layer 1 is a physical (PHY) layer. Layer 2 includes a MAC (Media Access Control) layer, an RLC (Radio Link Control) layer, and a PDCP (Packet Data Convergence Protocol) layer. Layer 3 includes an RRC (Radio Resource Control) layer.

The physical layer performs encoding / decoding, modulation / demodulation, antenna mapping / demapping, and resource mapping / demapping. Data is transmitted between the physical layer of the UE 100 and the physical layer of the eNB 200 via a physical channel.

The MAC layer performs data priority control, retransmission processing by hybrid ARQ (HARQ), and the like. Data is transmitted via the transport channel between the MAC layer of the UE 100 and the MAC layer of the eNB 200. The MAC layer of the eNB 200 includes a uplink / downlink transport format (transport block size, modulation / coding scheme, and the like) and a scheduler that selects allocated resource blocks.

The RLC layer transmits data to the RLC layer on the receiving side using the functions of the MAC layer and the physical layer. Data is transmitted between the RLC layer of the UE 100 and the RLC layer of the eNB 200 via a logical channel.

The PDCP layer performs header compression / decompression and encryption / decryption.

The RRC layer is defined only in the control plane. Control messages (RRC messages) for various settings are transmitted between the RRC layer of the UE 100 and the RRC layer of the eNB 200. The RRC layer controls the logical channel, the transport channel, and the physical channel according to establishment, re-establishment, and release of the radio bearer. When there is a connection (RRC connection) between the RRC of the UE 100 and the RRC of the eNB 200, the UE 100 is in a connected state (RRC connected state). Otherwise, the UE 100 is in an idle state (RRC idle state).

The NAS (Non-Access Stratum) layer located above the RRC layer performs session management and mobility management.

FIG. 6 is a configuration diagram of a radio frame used in the LTE system. In the LTE system, OFDMA (Orthogonal Frequency Division Multiplexing Access) is applied to the downlink, and SC-FDMA (Single Carrier Frequency Multiple Access) is applied to the uplink.

As shown in FIG. 6, the radio frame is composed of ten subframes arranged in the time direction, and each subframe is composed of two slots arranged in the time direction. The length of each subframe is 1 ms, and the length of each slot is 0.5 ms. Each subframe includes a plurality of resource blocks (RB) in the frequency direction and includes a plurality of symbols in the time direction. The resource block includes a plurality of subcarriers in the frequency direction.

Among radio resources allocated to the UE 100, frequency resources can be specified by resource blocks, and time resources can be specified by subframes (or slots).

In the downlink, the section of the first few symbols of each subframe is a control region mainly used as a physical downlink control channel (PDCCH). The remaining section of each subframe is an area that can be used mainly as a physical downlink shared channel (PDSCH). Also, in the downlink, reference signals such as cell-specific reference signals are distributed and arranged in each subframe.

In the uplink, both ends in the frequency direction in each subframe are control regions mainly used as a physical uplink control channel (PUCCH). Further, the central portion in the frequency direction in each subframe is an area that can be used mainly as a physical uplink shared channel (PUSCH).

(Operation according to the first embodiment)
Next, an operation according to the first embodiment will be described.

(1) Operating Environment FIG. 7 is a diagram for explaining the operating environment according to the embodiment. As illustrated in FIG. 7, the AP 300 is provided in the coverage of the eNB 200. The AP 300 is an AP (Operator controlled AP) managed by an operator.

In addition, a plurality of UEs 100 are located within the coverage of the eNB 200 and within the coverage of the AP 300. The UE 100 has established a connection with the eNB 200 and performs cellular communication with the eNB 200. Specifically, the UE 100 transmits and receives a cellular radio signal including traffic (user data) to and from the eNB 200. Or some UE100 does not need to establish the connection with eNB200.

In the first embodiment, it is assumed that the UE 100 compares the communication statuses of the eNB 200 and the AP 300 and can select the connection destination from the eNB 200 and the AP 300 by the UE 100 itself.

When the eNB 200 establishes connections with many UEs 100, the load level of the eNB 200 increases. A load level means the congestion degree of eNB200, such as the traffic load of eNB200, or the radio | wireless resource usage rate of eNB200. Here, the traffic load of the eNB 200 can be distributed to the WLAN system by shifting (offloading) at least part of the traffic transmitted and received between the UE 100 and the eNB 200 to the WLAN system.

Therefore, the plurality of UEs 100 start offloading to the AP 300 and establish a connection with the AP 300. Also, the plurality of UEs 100 release the connection with the eNB 200. As a result, a plurality of UEs 100 establish a connection with the AP 300 and do not establish a connection with the eNB 200 (idle state).

In this way, when the connection destination can be selected by the UE 100 itself from the eNB 200 and the AP 300, a plurality of UEs 100 can select the same AP 300 as the connection destination and start connection processing for the AP 300 all at once. Therefore, there is a possibility that a UE 100 that cannot establish a connection with the AP 300 may be generated due to a conflict in connection processing. In addition, even if all of these UEs 100 can establish a connection with the AP 300, there is a problem that sufficient throughput cannot be ensured due to an increase in the load level of the AP 300, or unused resources of the eNB 200 become excessive. . Hereinafter, an operation for solving such a problem will be described.

(2) Operation Sequence FIG. 8 is an operation sequence diagram according to the first embodiment.

As illustrated in FIG. 8, in step S <b> 11, the processor 240 of the eNB 200 transmits AP connection control information for randomly selecting the UE 100 that is allowed to connect to the AP 300 to the UE 100.

From the viewpoint of radio resource usage efficiency, the processor 240 may transmit the AP connection control information to the UE 100 by broadcasting. Further, the processor 240 may periodically transmit AP connection control information. Alternatively, the eNB 200 receives information on whether or not the WLAN communication unit 112 is on from the UE 100, and transmits the AP connection control information to the UE 100 on which the WLAN communication unit 112 is on by unicast. Good.

The AP connection control information specifies connection permission conditions for allowing connection with the AP 300. The AP connection control information is set based on the load level of the eNB 200. For example, the AP connection control information is set such that the higher the load level of the eNB 200, the higher the probability that the connection with the AP 300 is permitted. The AP connection control information is set such that the lower the load level of the eNB 200, the lower the probability that the connection with the AP 300 is allowed. A specific example of the AP connection control information will be described later.

The memory 150 of the UE 100 stores a UE identifier associated with the UE 100. The UE identifier is a C-RNTI (Cell-Radio Network Temporary Identifier) indicating a temporary identifier assigned from the eNB 200. Alternatively, the UE identifier is one of a unique identifier assigned in advance to the UE 100, a subscriber identifier assigned to the user of the UE 100, and an identifier (for example, an access class identifier) set according to the attribute of the UE 100. There may be.

The cellular communication unit 111 of the UE 100 receives AP connection control information from the eNB 200. The processor 160 determines whether or not to establish a connection with the AP 300 based on the AP connection control information received by the cellular communication unit 111 and the UE identifier stored in the memory 150. Below, operation | movement of UE100 is demonstrated.

(3) UE Operation Flow FIG. 9 is an operation flow diagram of the UE 100 according to the first embodiment. Here, it is assumed that the UE 100 has already received the AP connection control information from the eNB 200. Moreover, the case where the WLAN communication part 112 of UE100 is an ON state is assumed.

As shown in FIG. 9, in step S101, the processor 160 of the UE 100 determines whether or not the connection with the AP 300 is possible. For example, when the reception level of the beacon signal from the AP 300 is equal to or higher than the threshold, the UE 100 determines that the connection with the AP 300 is possible. Further, the UE 100 may determine that the connection with the AP 300 is possible when the AP load level information (that is, the load level of the AP 300) included in the beacon signal from the AP 300 is less than the threshold.

When it is determined that the connection with the AP 300 is possible (step S101: Yes), the processor 160 stores the first value (divNum) included in the AP connection control information and the memory 150 in step S102. And a UE identifier (UENum). In the first embodiment, the processor 160 calculates a remainder obtained by dividing the UE identifier (UENum) by the first value (divNum).

In step S103, the processor 160 determines whether or not a remainder value obtained by dividing the UE identifier (UENum) by the first value (divNum) matches the second value (remainerNum) included in the AP connection control information. Check.

When the remainder value obtained by dividing the UE identifier (UENum) by the first value (divNum) matches the second value (reminderNum) (step S103: Yes), the processor 160 connects to the AP 300 in step S104. Control to establish. Specifically, the processor 160 transmits a connection request to the AP 300 from the WLAN communication unit 112 to the AP 300.

As described above, in the first embodiment, the connection permission condition for allowing the connection with the AP 300 is that the remainder obtained by dividing the UE identifier (UENum) by the first value (divNum) is the second value (reminderNum). ).

In addition, the AP connection rate according to the load level of the eNB 200 can be realized by increasing or decreasing the quantity of the first value (divNum) according to the load level of the eNB 200. Alternatively, the AP connection rate according to the load level of the eNB 200 can be realized by expanding or reducing the numerical range of the second value (reminderNum) according to the load level of the eNB 200.

On the other hand, when the remainder obtained by dividing the UE identifier (UENum) by the first value (divNum) does not match the second value (reminderNum) (step S103: No), the processor 160 establishes a connection with the AP 300. Control not to. Specifically, the processor 160 switches the WLAN communication unit 112 to an off state. Alternatively, the processor 160 may stop decoding the beacon signal or transmitting it to the AP 300 while keeping the WLAN communication unit 112 on.

(Summary of the first embodiment)
The eNB 200 according to the first embodiment transmits AP connection control information for randomly selecting the UE 100 that is allowed to connect to the AP 300. The UE 100 controls not to establish a connection with the AP 300 when the UE identifier does not satisfy the connection permission condition defined by the AP connection control information received from the eNB 200. Thereby, even when a connection destination can be selected by the UE 100 itself from the eNB 200 and the AP 300, a plurality of UEs 100 can be prevented from starting connection processing to the AP 300 all at once.

In the first embodiment, the AP connection control information is set based on the load level of the eNB 200. Thereby, it can avoid that the load level of eNB200 becomes too large or too small.

In the first embodiment, the AP connection control information is set such that the higher the load level of the eNB 200, the higher the probability that the connection with the AP 300 is allowed. Thereby, when the load level of eNB200 is high, the active offload to AP300 is realizable.

In the first embodiment, the AP connection control information includes a first value (divNum) and a second value (reminderNum). The UE 100 controls not to establish a connection with the AP 300 when the result of calculating the UE identifier and the first value (divNum) does not match the second value (reminderNum). Thereby, since randomization of UE100 in which connection with AP300 is permitted is realizable, fairness is securable between UE.

[Second Embodiment]
The second embodiment will be described mainly with respect to differences from the first embodiment.

In the second embodiment, another operation for solving problems caused by a plurality of UEs 100 connecting to the same AP 300 all at once will be described. The system configuration and operating environment of the second embodiment are the same as those of the first embodiment.

(1) Operation Sequence FIG. 10 is an operation sequence diagram according to the second embodiment.

As illustrated in FIG. 10, in step S <b> 21, the processor 240 of the eNB 200 transmits a timer information table to the UE 100.

From the viewpoint of radio resource usage efficiency, the processor 240 may transmit the timer information table to the UE 100 by broadcasting. Further, the processor 240 may periodically transmit the timer information table. Alternatively, the eNB 200 may receive information on whether or not the WLAN communication unit 112 is in the ON state from the UE 100, and transmit the timer information table by unicast to the UE 100 in which the WLAN communication unit 112 is in the ON state. .

FIG. 11 is a diagram showing a specific example of the timer information table. As shown in FIG. 11, the timer information table is a table in which a waiting time (waiting time until connection to the AP 300) is associated with each predetermined numerical range. In this specific example, the waiting time is defined in subframe time units.

The cellular communication unit 111 of the UE 100 receives the timer information table from the eNB 200. The memory 150 stores the timer information table received by the cellular communication unit 111. The processor 160 determines whether or not to establish a connection with the AP 300 based on the timer information table. Below, operation | movement of UE100 is demonstrated.

(2) UE operation flow FIG. 12 is an operation flow diagram of the UE 100 according to the second embodiment. Here, it is assumed that the UE 100 has already received the timer information table from the eNB 200. Moreover, the case where the WLAN communication part 112 of UE100 is an ON state is assumed.

As shown in FIG. 12, in step S201, the processor 160 of the UE 100 determines whether or not the connection with the AP 300 is possible. For example, when the reception level of the beacon signal from the AP 300 is equal to or higher than the threshold, the UE 100 determines that the connection with the AP 300 is possible. Further, the UE 100 may determine that the connection with the AP 300 is possible when the AP load level information (that is, the load level of the AP 300) included in the beacon signal from the AP 300 is less than the threshold.

If it is determined that the connection with the AP 300 is possible (step S201: Yes), the processor 160 generates a random number in step S202. For example, the processor 160 generates a random number within a numerical range from 0 to 99.

In step S203, the processor 160 specifies the waiting time corresponding to the numerical range to which the random number generated in step S202 belongs based on the timer information table stored in the memory 150. For example, if the value of the random number is “57”, the time for 25 subframes is specified as the waiting time (see FIG. 11). That is, the processor 160 determines the timing after 25 subframes as the AP connection start timing for starting the connection with the AP 300. Then, the processor 160 starts the timer after setting the specified waiting time in the timer.

In step S204, the processor 160 acquires AP load level information (that is, the load level of the AP 300) included in the beacon signal that the WLAN communication unit 112 receives from the AP 300.

In step S205, the processor 160 confirms whether or not the load level of the AP 300 acquired in step S204 exceeds a threshold value. If the load level of the AP 300 exceeds the threshold (step S205: Yes), the process ends without establishing a connection with the AP 300.

On the other hand, when the load level of the AP 300 acquired in step S204 is equal to or less than the threshold value (step S205: No), in step S206, the processor 160 determines whether or not the timer has expired (that is, whether the waiting time has elapsed). Confirm).

If the timer has expired (step S206: Yes), in step S207, the processor 160 controls to establish a connection with the AP 300. Specifically, the processor 160 transmits a connection request to the AP 300 from the WLAN communication unit 112 to the AP 300.

On the other hand, when the timer has not expired (step S206: No), the processor 160 returns the process to step S204.

(Summary of the second embodiment)
UE100 which concerns on 2nd Embodiment delays AP connection start timing which starts the connection with AP300 according to a random number, when it is judged that the connection with AP300 is started. Thereby, even when a connection destination can be selected by the UE 100 itself from the eNB 200 and the AP 300, a plurality of UEs 100 can be prevented from starting connection processing to the AP 300 all at once.

In the second embodiment, the UE 100 acquires information indicating the load level of the AP 300 during the waiting time until the AP connection start timing. When the acquired load level exceeds the threshold value, the UE 100 stops the connection with the AP 300. Thereby, the waiting time until the AP connection start timing can be effectively utilized. Further, it is possible to prevent establishment of a connection with the AP 300 whose sufficient throughput cannot be expected.

In the second embodiment, the UE 100 specifies the waiting time corresponding to the numerical range to which the random number belongs based on the timer information table. And UE100 determines AP connection start timing from the specified waiting time. Thereby, AP connection start timing can be determined appropriately.

In the second embodiment, the timer information table is set from the eNB 200. Thereby, the timer information table suitable for the communication environment in the coverage of eNB200 can be set to UE100.

[Other Embodiments]
In the first embodiment described above, the AP connection control information includes the first value (divNum) and the second value (reminderNum). However, the AP connection control information may be a single threshold value, for example. In this case, the UE 100 determines whether or not AP connection is possible depending on whether or not the UE identifier exceeds a threshold value. Moreover, you may adjust a threshold value according to the load level of eNB200.

In the second embodiment described above, the timer information table is set from the eNB 200. However, the UE 100 may hold a timer information table in advance.

In the above-described embodiment, the LTE system has been described as an example of the cellular communication system. However, the present invention is not limited to the LTE system, and the present invention may be applied to systems other than the LTE system.

Note that the entire content of Japanese Patent Application No. 2013-100788 (filed on May 10, 2013) is incorporated herein by reference.

Claims

A user terminal that supports cellular communication and WLAN communication,
A storage unit for storing an identifier associated with the user terminal;
A receiving unit for receiving connection control information for randomly selecting a user terminal allowed to connect to an access point from a cellular base station;
And a control unit that controls not to establish a connection with the access point when the identifier does not satisfy a connection permission condition defined by the connection control information.
The user terminal according to claim 1, wherein the connection control information is set based on a load level of the cellular base station.
The user terminal according to claim 2, wherein the connection control information is set such that the higher the load level of the cellular base station, the higher the probability that connection with the access point is allowed.
The connection control information includes a first value and a second value,
2. The control unit according to claim 1, wherein when the result of calculating the identifier and the first value does not match the second value, control is performed so as not to establish a connection with the access point. The user terminal described in 1.
A processor provided in a user terminal that supports cellular communication and WLAN communication,
Receiving connection control information for randomly selecting user terminals allowed to connect to the access point from the cellular base station;
Performing control so as not to establish a connection with the access point when an identifier associated with the user terminal does not satisfy a connection permission condition defined by the connection control information. Processor.
A user terminal that supports cellular communication and WLAN communication,
A user terminal comprising: a control unit that delays start timing for starting connection with the access point according to a random number when it is determined to start connection with the access point.
The control unit obtains information indicating a load level of the access point in a waiting time until the start timing,
The said control part stops the connection with the said access point, when the acquired load level exceeds a threshold value, The user terminal of Claim 6 characterized by the above-mentioned.
A storage unit for storing a table in which waiting times are associated with each predetermined numerical range;
The control unit identifies the waiting time corresponding to a numerical range to which the random number belongs based on the table,
The said control part determines the said start timing from the specified waiting time, The user terminal of Claim 6 characterized by the above-mentioned.
The user table according to claim 8, wherein the table is set from a cellular base station.
A processor provided in a user terminal that supports cellular communication and WLAN communication,
A processor characterized by delaying a start timing of starting connection with the access point according to a random number when it is determined to start connection with the access point.