JP6411853B2 - Wireless communication system, mobile communication base station, wireless terminal device, and wireless communication method - Google Patents

Description

  The present invention relates to a radio communication system, a mobile communication base station, a radio terminal apparatus, and a radio communication method that use a plurality of frequency bands together.

  2. Description of the Related Art Conventionally, wireless terminal devices such as smartphones that can use both a communication using a shared frequency band, which is a frequency band that does not require a license, such as a wireless LAN, and a communication using a licensed frequency band that requires a license. is there. On the other hand, the throughput of a wireless LAN system defined by the standard IEEE 802.11 has been improving year by year, and it has become widespread as one of the main wireless accesses (for example, see Non-Patent Document 1).

  Since the wireless LAN system can be used in a shared frequency band, which is an unlicensed frequency band, a wide variety of wireless terminals are in widespread use. Particularly, the spread of smartphones significantly increases the use of wireless LAN. The frequency bands that can be used in the wireless LAN system, which is a shared frequency band, are assigned to 2.4 GHz, 5 GHz, and 60 GHz. Even if only the 2.4 GHz and 5 GHz microwave bands in Japan are considered, the frequency is as high as about 500 MHz. Can be used. Further, as a use of the shared frequency band, 3GPP, which considers mobile communication systems, has begun to study as Licensed Assisted Access (LAA), and has attracted attention (for example, see Non-Patent Document 2).

  Also, in communication using a shared frequency band such as an unlicensed band such as an ISM band that does not require a license, or a frequency band in which multiple wireless systems can coexist, such as power-saving radio and cognitive radio, the degree of congestion of the terminal device to be accessed and traffic In addition to the decrease in throughput due to the interference, interference from other wireless systems (Inter system interference) also affects. For example, in a shared frequency band in which a wireless LAN is used, it coexists with various wireless systems such as radar, medical equipment, microwave oven, amateur wireless, Bluetooth (registered trademark).

  Furthermore, when communication is performed based on CSMA / CA (Carrier sense multiple access / collision avoidance), throughput is also reduced due to the exposed terminal problem and the hidden terminal problem. As described above, the communication in the shared frequency band is affected by various factors, and sometimes the line is cut off due to a significant deterioration in quality. For this reason, when using communication using a shared frequency band, it is important for grasping the radio environment information in detail to improve the user experience.

IEEE, “Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications,” Dec. 2013. RP-140057, “On the primacy of licensed spectrum in relation to the proposal of using LTE for a licensed-assisted access to unlicensed spectrum,” 3GPP TSG-RAN # 63, Mar. 2014.

  In order to cope with the rapid increase in traffic in the future, when using communication in the frequency band where multiple systems coexist in addition to communication in the licensed frequency band, as described above, the communication quality of the shared frequency significantly decreases depending on the communication environment. Therefore, it is necessary to grasp in detail the radio environment information using the shared frequency.

  However, a radio frequency communication system in a licensed frequency band does not have a means to grasp in detail the radio environment information in the shared frequency band that does not require a license, so the status of the radio environment in the shared frequency band can be accurately grasped. There is a problem that you can not.

  The present invention has been made in view of such circumstances, and uses a wireless communication system operated in a licensed frequency band, via a wireless terminal device capable of communicating in both a licensed frequency band and a shared frequency band. It is an object of the present invention to provide a wireless communication system, a mobile communication base station, a wireless terminal device, and a wireless communication method that can acquire wireless environment information in a shared frequency band under specified conditions.

  The present invention uses a licensed frequency band between a wireless terminal device capable of wireless communication using a shared frequency band that does not require a license and a licensed frequency band that requires a license, and the wireless terminal device. A wireless communication system including a mobile communication base station that performs wireless communication, wherein the wireless terminal device measures specific wireless environment information of the shared frequency band from the received wireless signal of the licensed frequency band Alternatively, a radio environment measurement control signal extraction unit that acquires a radio environment measurement control signal indicating information collection conditions for feeding back measured radio environment information or both, and a specific radio in the shared frequency band according to the radio environment measurement control signal A wireless environment measurement unit that measures environment information; and a wireless environment information transmission unit that transmits the measured wireless environment information to the mobile communication base station. The station generates a radio environment measurement control signal indicating a condition and / or measurement contents for measuring the radio environment information necessary for estimating the communication status of the shared frequency band, and transmits the radio environment measurement control signal to the radio terminal apparatus A radio environment measurement control signal generation unit for transmitting, and a radio environment information storage unit for receiving and storing the radio environment information transmitted from the radio terminal device.

  In the present invention, the radio environment measurement control signal generation unit uses application information, mobility information, used radio access mode information, position information, communication abnormality information in communication with the radio terminal device in the licensed frequency band. The wireless terminal device that requests the wireless terminal device to measure the wireless environment information of the shared frequency band or to collect the measured information when the collected information satisfies a predetermined condition An environmental measurement control signal is generated.

  In the present invention, the radio environment measurement control signal generation unit detects the establishment or disconnection of the connection with the shared frequency band base station of the radio terminal apparatus or the communication abnormality in which the radio communication in the shared frequency band does not satisfy a predetermined condition. The detection is added to the radio environment measurement control signal as a condition for measuring the radio environment of the shared frequency band or collecting the measured information.

  In the present invention, the radio environment measurement control signal generation unit detects the identification information of a specific shared frequency band base station, detects a broadcast signal of a specific shared frequency band base station, specific position information, and a specific time. It is added to the radio environment measurement control signal as a condition for measuring the radio environment of the frequency band or collecting the measured information.

  The present invention further comprises a second mobile communication base station having a function of transmitting and receiving a user data signal to and from the radio terminal device in the licensed frequency band, and the radio environment measurement control signal generator is Detection of start or end of communication of user data with the mobile communication base station or the second mobile communication base station to communicate, or traffic congestion of the mobile communication base station or the second mobile communication base station with which communication is performed The detection of whether or not the status index exceeds a predetermined value is added to the radio environment measurement control signal as a condition for measuring the radio environment in the shared frequency band or collecting the measured information.

  In the present invention, the mobile communication base station acquires external information other than communication that can affect the communication status from an external network, and the wireless environment information storage unit is affected by the external information based on the external information, Information collected about position and identification information is managed by external information.

  In the present invention, the radio environment measurement control signal generator determines radio terminal devices to be measured as to whether they can be detected in the shared frequency band as a correlation check group, and information for measuring whether signals can be detected with each other In the wireless environment measurement control signal, the wireless terminal device transmits a wireless signal including its own identification information in the shared frequency band when the correlation confirmation group is designated in the wireless environment measurement control signal. At the same time, it is characterized in that it is determined whether or not identification information of another wireless terminal device of the correlation confirmation group is detected.

  In the present invention, the radio environment measurement control signal generation unit determines at least part of conditions for measuring the radio environment of the shared frequency band specified by the radio environment measurement control signal, and determines that the conditions are satisfied. The wireless environment measurement control signal is transmitted as described above.

  The present invention uses a licensed frequency band between a wireless terminal device capable of wireless communication using a shared frequency band that does not require a license and a licensed frequency band that requires a license, and the wireless terminal device. A wireless terminal apparatus in a wireless communication system comprising a mobile communication base station that performs wireless communication, wherein a measurement condition for measuring specific wireless environment information of the shared frequency band from the received wireless signal of the licensed frequency band or A radio environment measurement control signal extraction unit that acquires a radio environment measurement control signal indicating a measurement condition and an information collection condition for feeding back the measured radio environment information, and according to the radio environment measurement control signal, the radio environment information of the shared frequency band is obtained. A radio environment information transmission unit that transmits the measured radio environment information to the mobile communication base station according to a radio environment measurement unit to be measured and specified information collection conditions. Characterized in that it comprises a part.

  The present invention uses a licensed frequency band between a wireless terminal device capable of wireless communication using a shared frequency band that does not require a license and a licensed frequency band that requires a license, and the wireless terminal device. A mobile communication base station in a wireless communication system comprising a mobile communication base station that performs wireless communication, the wireless environment information necessary for estimating the communication status of the shared frequency band and the measurement conditions or the measured wireless environment A radio environment measurement control signal generation unit that generates a radio environment measurement control signal indicating an information collection condition for feeding back information and transmits the signal to the radio terminal device; and the radio environment information transmitted from the radio terminal device. And a wireless environment information storage unit for receiving and storing.

  The present invention uses a licensed frequency band between a wireless terminal device capable of wireless communication using a shared frequency band that does not require a license and a licensed frequency band that requires a license, and the wireless terminal device. A wireless communication method performed by a wireless communication system including a mobile communication base station that performs wireless communication, wherein the mobile communication base station requires wireless environment information that needs to be measured in order to estimate a communication status of the shared frequency band; A radio environment measurement control signal generation step of generating a radio environment measurement control signal indicating the measurement conditions or information collection conditions for feeding back the measured radio environment information or both, and transmitting the radio environment measurement control signal to the radio terminal device; and the radio A radio environment indicating a measurement condition and / or measurement contents for measuring radio environment information of the shared frequency band from the received radio signal of the licensed frequency band by the terminal device A radio environment measurement control signal extracting step for obtaining a constant control signal, and a radio environment measurement step for measuring the radio environment information of the shared frequency band according to the measurement condition specified by the radio environment measurement control signal by the radio terminal device A wireless environment information transmitting step in which the wireless terminal device transmits the measured wireless environment information to the mobile communication base station according to an information collection condition specified by the wireless environment measurement control signal; and the mobile communication A base station includes a radio environment information storage step of receiving and storing the radio environment information transmitted from the radio terminal device.

  According to the present invention, a mobile station base station that performs communication in a licensed frequency band efficiently transmits necessary measurement information of the shared frequency band by transmitting a measurement signal indicating the measurement condition of the shared frequency band to the wireless terminal device. It is possible to collect, and the effect that the radio environment of the shared frequency band can be grasped in more detail is obtained.

It is a block which shows the structure of the radio | wireless communications system in one Embodiment of this invention. It is a block diagram which shows the structure of the mobile communication base station 1 of the license frequency band shown in FIG. It is a block diagram which shows the structure of the user terminal 2 shown in FIG. It is a flowchart which shows the control operation of a radio | wireless communications system. It is a flowchart which shows the processing operation of radio | wireless environment acquisition of a mobile communication base station judgment type about acquisition of radio | wireless environment information from the user terminal 2 of LC active. It is a flowchart which shows the processing operation of the radio | wireless environment acquisition of the user terminal 2 judgment type about acquisition of the radio | wireless environment information from the user terminal 2 of LC active. It is explanatory drawing for demonstrating the effect of this invention. It is a figure which shows the cumulative probability distribution of the throughput obtained with the user terminal 2 when the utilization condition of the radio | wireless resource of all the links is given at random.

  Hereinafter, a wireless communication system according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a wireless communication system in the embodiment. FIG. 1 shows a configuration of a radio communication system surrounding a user terminal and a mobile communication base station. In FIG. 1, a radio communication system includes a mobile communication base station 1, L (L is a natural number) user terminals 2-1 to L, N (N is a natural number) shared frequency band base stations 3-1 to N, M (M is a natural number including 0) second mobile communication base stations 4-1 to 4 -M and a UC radio environment information storage unit 5. The i-th (i is a natural number) user terminal 2-i performs radio communication with the mobile communication base station 1 and, based on the UC radio environment measurement control signal transmitted from the mobile communication base station 1, Collect radio environment information. Further, the user terminal 2-1 can also communicate with the shared frequency band base stations 3-1 to N, and in FIG. 1, the user terminal 2-1 can perform data communication with the shared frequency band base station 3-1 by a dotted line. Show.

  The user terminal 2-1 is shared not only with the communicable shared frequency band base station 3-1, but also with other radio terminal apparatuses including other shared frequency band base stations 3-2 to N and user terminals using the shared frequency band. You may acquire the radio | wireless environment information regarding the communication in a frequency band. Some shared frequency band base stations 3-1 to 3 -N can also acquire the radio environment information of the shared frequency band using backhaul communication and store it in the UC radio environment information storage unit 5. The UC radio environment information storage unit 5 does not necessarily exist in the mobile communication base station 1 and may exist on a network that can communicate with the mobile communication base station 1.

  Furthermore, the mobile communication base station 1 may communicate with the second mobile communication base stations 4-1 to M that can perform data communication in a frequency band other than the shared frequency band with the user terminal 2-1. FIG. 1 shows that the user terminal 2-1 can communicate with the second mobile communication base station 4-1. For example, the second mobile communication base station can communicate only the user data signal with the user terminal 2-1, not the control signal using the licensed frequency band, and has a large capacity using a millimeter wave, a submillimeter wave, or the like. A small cell is a mobile communication base station managed by the mobile communication base station 1 using a frequency different from that of the mobile communication base station 1.

  The mobile communication base station 1 can also collect information such as traffic, throughput, and delay time from the second mobile communication base stations 4-1 to 4 -M through the backhaul communication system. The mobile communication base station 1 can also transmit and receive user data signals communicated with the second mobile communication base stations 4-1 to 4 -M via the mobile communication base station 1. From the user terminals 2-1 to L, identification information for the mobile communication base station 1, the second mobile communication base station 4, the shared frequency band base station 3, and other user terminals can be acquired, and radio environment information can be acquired. . Then, it is possible to efficiently collect necessary radio environment information by setting conditions for measurement of radio environment information in the shared frequency band and collection (notification) of the measured information.

  Next, the configuration of the mobile communication base station 1 shown in FIG. 1 will be described with reference to FIG. FIG. 2 is a block diagram showing the configuration of the mobile communication base station 1 in the licensed frequency band shown in FIG. When the configuration of the mobile communication base station 1 is described with reference to FIG. 2, the well-known functions and configurations that the mobile communication base station normally has are described and explained unless it is directly related to the description of the present invention. Illustration of the configuration is omitted.

  In FIG. 2, reference numeral 11 denotes an antenna (LC antenna) corresponding to a licensed frequency band channel (LC). Reference numeral 12 denotes an LC transmitter / receiver that transmits and receives radio signals in the licensed frequency band. Reference numeral 13 denotes an information signal input / output unit that inputs and outputs information signals. Reference numeral 14 denotes a UC radio environment measurement control signal generation unit that generates a UC (UC: Unlicensed Channel) radio environment measurement control signal. Reference numeral 5 denotes a UC wireless environment information storage unit that stores UC wireless environment information, and includes the UC wireless environment information storage unit 5 shown in FIG. Here, a plurality of LC transceivers 12 and LC antennas 11 may be provided in order for the LC to support a plurality of frequencies. Reference numeral 16 denotes a UC communication status evaluation unit that evaluates the UC communication status. Reference numeral 17 denotes an LC communication evaluation unit that evaluates LC communication. Note that the LC communication evaluation unit 17 is not an essential configuration and may not be provided.

  The mobile communication base station 1 communicates with the user terminal 2 in the licensed frequency band via the LC antenna 11. When receiving a signal from the user terminal 2, the LC transmission / reception unit 12 acquires data information transmitted by the user terminal 2 through processes such as down-conversion, synchronization, and decoding, and outputs the data information to the information signal input / output unit 13. When a UC radio environment measurement signal including measurement information of a shared frequency band (UC: Unlicensed Channel) that does not require a license is detected, the information signal input / output unit 13 extracts the UC radio environment information. , Output to the UC wireless environment information storage unit 5.

  The UC radio environment information includes, for example, identification information in the UC of the user terminal 2 using a shared frequency band, identification information of a shared frequency band base station that is a connection destination, and a type of signal received in the shared frequency band (transmission or destination identification Information, signal type), information on signal power of received signal (RCPI: Received channel power indicator, RSNI: Received signal to noise indicator, RSSI: Received signal strength indicator, RSRP: Reference signal received power, RSRQ: Reference Signal Received Quality), communication occupancy rate (channel utilization rate, BSS load: Basic service set load), information on propagation loss between wireless devices corresponding to identification information, distance information for identification information, shared frequency band base station to user terminal 2 or a packet error rate in communication from the user terminal 2 to the shared frequency band base station And throughput information such as data rate of the physical layer, delay time of communication with the shared frequency band base station, radio signal occupancy rate in the channel used by the shared frequency band base station that is the connection destination, shared frequency band that is the connection destination Base station channel usage information (channel usage rate, BSS load), multiuser simultaneous transmission technology usage rate, multiuser simultaneous transmission technology success rate, frame aggregation usage information, RTS / CTS usage information, guard interval mode information, packet length information Other system interference information, broadcast signal information notified from a shared frequency band base station that performs communication in the shared frequency band. The mobile communication base station 1 collects at least one of these from the user terminal 2 or both of the user terminal 2 and the shared frequency base station 3-i (i is one or more natural numbers of 1 or more and N or less), Remember. Here, the multi-user simultaneous transmission technology is a downlink multi-user MIMO (Multiple input multiple output) technology using spatial multiplexing, an uplink multi-user MIMO technology, or OFDMA (Orthogonal frequency division multiplexing access) using frequency multiplexing. It is technology. As this broadcast signal information, for example, a signal defined by IEEE802.11u or IEEE802.11k can be used.

  The UC communication status evaluation unit 16 evaluates the communication status obtained by UC from the information stored in the UC wireless environment information storage unit 5. The communication status is the traffic status in the shared frequency band and / or the communication quality in the shared frequency band. The traffic status in the UC is the packet error rate, delay time, radio signal occupancy rate, channel utilization rate, BSS load, and information related to traffic included in the broadcast signal transmitted from the shared frequency band base station acquired as UC radio environment information. (Estimated from the number of connected terminals, backhaul information, radio resource tightness, etc.).

  On the other hand, the communication quality includes the identification information of the shared frequency band base station to which the user terminal 2 is connected, the packet in the communication from the shared frequency band base station to the user terminal 2 or the communication from the user terminal 2 to the shared frequency band base station. Information on throughput such as error rate and physical layer data rate, information on received signal power, delay time of communication with shared frequency band base station, multi-user simultaneous transmission technology utilization rate, multi-user simultaneous transmission technology success rate, frame aggregation utilization Information, RTS / CTS utilization information, guard interval mode information, packet length information, other system interference information, identification information of wireless terminals that communicate on the detected channel in the shared frequency band, shared frequency band base that communicates in the shared frequency band It can be estimated from the broadcast signal information notified from the station.

  When parameters directly related to throughput, such as packet error rate measurement results, are collected and stored in combination with time, terminal location, and connection destination identification information, the user terminal 2 may use UC or share frequency bands in the future. When selecting a base station, it is possible to select a base station having high communication quality. In order to evaluate more accurate throughput characteristics, it is determined whether the identification information detected by the UC radio environment information can be detected from each other, a connection between the identification information is established, and a generation condition of a frame transmitted by the identification information is assumed. By doing so, it is possible to perform throughput evaluation that simulates the hidden terminal problem and the exposed terminal problem.

  At this time, a UC traffic model may be included in the UC communication status evaluation unit 16 in order to estimate the traffic status with higher accuracy. This UC traffic model can be constructed from UC radio environment information related to the measured traffic situation. The traffic model can use not only information related to traffic in the collected UC wireless environment information but also information other than communication such as traffic status in LC, concerts, sports events, festivals, disasters, traffic troubles, weather, etc. -It can also be constructed from empirical traffic fluctuation information for time information such as day of the week and time.

  Furthermore, the UC communication status evaluation unit 16 performs the above-described processing on the time information such as the position of the user terminal 2, the terminal function, the identification information of the detected wireless device, the application used, the user grade, and the day / date / time. By associating the communication quality information, the communication quality of throughput or delay time when using UC may be estimated from information of an arbitrary user terminal 2. Based on the estimated traffic status or communication quality information, the LC transceiver unit 12 can transmit a signal related to the use of the shared frequency band to the user terminal 2. The signal related to the use of the shared frequency band is, for example, designation of a connection destination, notification of a policy at the time of connection, or notification of traffic status or communication quality of the shared frequency band. Examples of how to use the UC radio environment information other than the transmission of signals related to the use of the shared frequency band to the user terminal 2 include examination of new installation of the shared frequency band base station 3.

  The UC radio environment measurement control signal generator 14 determines radio environment information measurement conditions for the shared frequency band and UC radio environment information collection conditions. The collection conditions of the UC wireless environment information are the same as the measurement conditions of the wireless environment information, and can be collected immediately after collecting the UC wireless environment information.

  The UC wireless environment information stored in the UC wireless environment information storage unit 5 includes static information with little change, quasi-static information that is easy to predict for time conditions such as day of the week, date, and time, and seconds / minutes.・ It is divided into dynamic information that fluctuates dynamically on a time scale and is difficult to predict. Since the static information has few large fluctuations, it is possible to update and manage the radio environment information of the shared frequency band by periodically measuring. The static information is, for example, the identification information of the shared frequency band base station 3 in the area where the mobile communication base station can communicate, the backhaul information of the shared frequency band base station 3, and the backhaul of the shared frequency band base station 3 are connected. Information on fixed functions such as node information such as gateways, location information of shared frequency band base station 3, utilization of frequency bandwidth of shared frequency band base station 3, RTS / CTS utilization, guard interval mode information, shared frequency band Information included in the broadcast signal of the base station 3.

  Since these pieces of information do not change instantaneously, the measured information can be collected by measuring the information at a timing when no load is applied to the line or at a constant period. For information measurement at a fixed period, the UC radio environment measurement control signal generation unit 14 of the mobile communication base station 1 determines a user terminal 2 that collects radio environment information of the shared frequency band, or all users in communication As broadcast information addressed to the terminal 2, it is possible to generate and transmit a UC radio environment measurement control signal instructing UC radio environment information collection. The determination method of the user terminal 2 can be determined by the contract form of the owner who owns the user terminal 2, the function of the user terminal 2, the position of the user terminal 2, and the communication quality status of the LC communication of the user terminal 2. As a condition for collecting the measured information, it is better to collect the UC radio environment information from the user terminal 2 that has a high LC communication throughput or to collect the LC communication traffic at a timing when the traffic volume of the LC communication is low. The load is small. If the throughput is large with respect to the bit amount of the UC wireless environment information, the bit amount can be transmitted with a small amount of time / frequency resources, and if the traffic amount is small, the LC communication is not affected. can do. Instead of measuring at a fixed period, measurement at a specific time may be performed. Further, if there is a margin in LC traffic, information measured periodically or at a specific time can be collected. In this way, the wireless environment information can be measured in detail at a specific time.

  Since the static information has little fluctuation, when it can be determined that the user terminal 2 has moved to a position where estimation has not been performed, or a position where new estimation has not been performed for a long time since estimation has been performed in the past, It can also be designated by a UC radio environment measurement control signal generated in the mobile communication base station 1 so as to acquire the radio environment information of the shared frequency band. In addition to the position information, information that can be detected by the user terminal 2, the mobile communication base station 1, or the shared frequency band base station 3, such as detected identification information, weather, and sudden events, may be used.

  The quasi-static information is information that can be predicted for temporal conditions such as day of the week, date, and time. The quasi-static information can also acquire significant UC radio environment information by performing measurements on regular or specific time information. Which information is quasi-static differs depending on the installation environment of the shared frequency base station and the mobile communication base station. For example, the number of user terminals using a shared frequency band for time information, the number of connected user terminals for the identification information of the shared frequency band base station for time information, the amount of traffic flowing in the shared frequency band for time information, and time information Information depending on the backhaul and network configuration, such as the radio resource utilization rate for the network and the delay time of communication with the shared frequency band base station, can be considered. Since collection of quasi-static information is important to correlate with time information, a time condition is added to the radio environment measurement condition or a UC radio environment measurement signal for performing measurement at the time is transmitted from the mobile communication base station 1. You just have to do it.

  The dynamic information includes information on throughput such as packet error rate and physical layer data rate in communication from the shared frequency band base station 3 to the user terminal 2 or communication from the user terminal 2 to the shared frequency band base station 3, Occupancy rate, channel usage rate, multi-user simultaneous transmission technology usage rate, multi-user simultaneous transmission technology success rate, frame aggregation usage information, packet length information, other system interference information, identification of user terminals communicating on channels in shared frequency band Information, broadcast signal information notified from the shared frequency band base station 3 that performs communication in the shared frequency band. However, as described above, the dynamic information can be quasi-static information in the installation environment.

  For dynamic information collection, dynamic fluctuations can be detected by shortening the aforementioned information collection period or by narrowing the time interval of a specific scheduled time. For example, the radio resources of the user terminal 2 and LC and the load on the mobile communication base station 1 are increased. For this reason, it is important to reduce the load by specifying the UC wireless environment measurement conditions. As a method for limiting the measurement conditions, there may be a limitation on the user terminal 2 that performs the measurement, a limitation on the time condition on which the measurement is performed, a limitation on identification information of the specific shared frequency band base station 3, a limitation on the frequency channel, and the like. For this reason, it is important to determine in advance conditions such as time and place where it is important to perform communication by UC. When limited by time conditions, the time when it is important to perform communication by UC is the time when traffic in LC increases, the time when the number of subordinate user terminals L increases, and the time when there are many UC communication abnormality reports The time when the number of pieces of identification information detected by the UC is large, the time when the traffic situation at the UC is high, and the like can be considered. As the identification information, in the UC wireless environment information storage unit 5, the shared frequency band base station whose communication characteristics change such as unstable throughput and delay time, high frequency of line disconnection, and long time required for connection establishment. It is possible to extract the identification information and cause the user terminal 2 that has detected the identification information to measure the radio environment information related to the frequency channel used by the shared frequency band base station 3. If there is a feature in the position where the UC communication abnormality is reported, the position can be used as a condition. By acquiring detailed UC wireless environment information at a timing when the necessity of UC communication is high, it is possible to prevent a user experience from being deteriorated.

  Alternatively, in the UC radio environment information storage unit 5, the identification information of the shared frequency band base station 3 that is a cause of causing a hidden terminal or an exposed terminal that is high in the frequency of transmission / reception that is tightening radio resources is selected, The user terminal 2 detecting this identification information is caused to measure the radio environment information related to the frequency channel used by the shared frequency band base station 3. Or, in order to evaluate other systems such as microwave ovens, radar, amateur radio, medical equipment and communication troubles with unknown causes, the location, time information, frequency channel, The wireless environment information is measured by limiting to at least one of the above. For example, the UC radio environment information storage unit 5 monitors the throughput and traffic status of communication using the UC, and extracts the identification information of the time, position, and shared frequency band base station where the traffic volume in the UC is particularly high. Measure information about position and identification information. When measuring the throughput as the measurement contents, the measurement is specified for the user terminal 2 currently performing communication in the UC, and items that can be measured simply by receiving a radio signal in the UC are currently communicated in the UC. It is possible to cause the user terminal 2 that has not performed

Hereinafter, some examples of the UC wireless environment information measurement condition and the collection condition will be shown.
(1) Radio environment information measurement or collection of UC radio environment information triggered by LC communication between the user terminal 2 and the mobile communication base station In the first example, the user terminal 2 communicates with the mobile communication base station 1 and the LC. The measurement and / or collection of the UC radio environment information is performed by using a specific timing as a trigger. In the first example, the load on the LC line is reduced by making the measurement and information collection of the UC radio environment information associated with some LC communication without newly calling the user terminal 2. it can. A trigger moves into the cell of the mobile communication base station 1 by a handover, and a logical communication path (user plane path) passes between the mobile communication base station and a packet gateway (PDN gateway) and a user terminal. Communication with the mobile communication base station 1 is started (for example, when communication with the second mobile communication base station 4 or the shared frequency band base station 3 is terminated). When the status of the control signal that can be collected from the user terminal 2 by LC communication satisfies a specific condition (for example, the timing when the mobility / position information of the user terminal 2 satisfies a specific condition), LC communication is performed Change of the communication form of the user terminal. For example, a change in the communication form detects a change in the application to be used or a change in traffic, and notifies the measurement or collection of the UC radio environment information. UC radio environment information that can be collected by the user terminal 2 that is considered to be stopped at the same position because low mobility is a typical condition for obtaining high performance in communication with the shared frequency band base station 1. Is considered to be of high value. For this reason, by collecting the mobility / position information of the user terminal 2 performing the LC communication and using it as a condition for measuring the UC radio environment information, the UC radio environment information under a condition that the shared frequency band is considered easy to use. Is possible. In addition to mobility information, a mobile communication base station or second mobile communication using a communication line or specific application such as a millimeter wave or optical radio that cannot be used if it can be determined that it stays at the same position for a certain period of time or if it is not stationary. When communicating with the base station, the measurement of the shared frequency band may be started. In addition, when used as a collection condition, when there is some trouble such as low throughput, high delay time, connection disconnection in communication with the shared frequency band base station 3, when switching to communication with the mobile communication base station 1, The mobile communication base station apparatus can be immediately notified of the trouble and the identification information of the corresponding shared frequency band base station 3.

(2) Radio environment information measurement or collection of UC radio environment information triggered by UC communication between the user terminal and the shared frequency band base station In the second example, the user terminal 2 communicates with the shared frequency band base station 3 and the UC. UC radio environment information is measured and / or collected by using the timing of performing ACK as a trigger. The second example has an advantage that information in an environment where the UC is actually used can be obtained by measuring the radio environment information at the user terminal at a timing when UC communication is required. Further, when the communication with the LC is performed until the communication with the shared frequency band base station is started, the UC wireless environment information can be efficiently notified (collected) at the timing when the communication with the LC is finished. it can. By notifying the mobile communication base station of the identification information of the shared frequency band base station that starts connection or communication by LC, how many user terminals communicate with which shared frequency band base station in the UC radio environment information storage unit 5 It is also possible to estimate in real time whether this is likely. In addition, when used as a collection condition, when switching to communication with a mobile communication base station in a short time after collecting UC radio environment information information, it is estimated that there was some problem in communication with the shared frequency band base station 3 You can also. In this case, in combination with the first example, by collecting information on troubles such as low throughput, high delay time, disconnection at the start of communication with the mobile communication base station, by comparing the prior information and the subsequent information, You can know the details of the trouble in more detail. Furthermore, the status of UC communication can also be made a condition. That is, a state in which communication at the UC is continuously performed (UC active), a state in which a signal at the UC can be received, but a data frame is not currently transmitted / received (UC idle), and a UC transmission / reception This is a determination based on a state in which the circuit is not turned on (UC off). Furthermore, a traffic condition in UC active may be added. For example, for the UC active user terminal 2, measurement relating to throughput, for the UC idle user terminal 2, information that can be measured without transmitting a data frame, for example, detection of identification information of a wireless device, radio signal occupancy, The contents of measurement may be assigned by acquiring channel utilization rate, broadcast signal information of the shared frequency band base station 2, and not collecting radio environment information of the UC when the UC is off.

(3) Radio environment information measurement or collection of UC radio environment information based on information required by the UC communication status evaluation unit 16 In the third example, based on the evaluation result of the UC communication status evaluation unit, the radio environment measurement condition or the radio environment Determine measurement and collection conditions. An object is to collect information necessary for estimating traffic and / or communication quality in the UC communication status evaluation unit 16. The UC communication status evaluation unit 16 outputs conditions necessary for evaluating the communication status to the UC radio environment measurement control signal generation unit 14 via the information signal input / output unit 13. Necessary information is information relating to traffic or communication quality for specific identification information, or UC radio environment information at a specific time, and measurement is performed on the user terminal 2 which is the condition in the UC radio environment measurement control signal. This makes it possible to estimate the UC communication quality in more detail.

(4) Radio environment information measurement or collection of UC radio environment information based on LC communication status In the fourth example, radio environment measurement conditions or radio environment measurement conditions and collection based on the LC communication evaluation results of the LC communication evaluation unit 17 Determine the conditions. The fourth example is mainly intended to offload LC communication between the mobile communication base station 1 and the user terminal 2 to the UC in the mobile communication system, and the bottleneck of the LC communication occurs under any conditions. Is estimated in advance by the LC communication evaluation unit 17, the condition is notified to the UC radio environment measurement control signal generation unit 14 via the information signal input / output unit 13, and when the condition is satisfied, the UC radio environment information is transmitted to the user terminal. 2 and collecting the UC radio environment information necessary for offloading from the LC line, the mobile communication base station 1 can efficiently switch to or use the UC line in communication with the user terminal 2 Like that. Examples of the bottleneck of LC communication include an increase in traffic in LC, an increase in the number of subordinate user terminals L, and an increase in the number of user terminals 2 that are far away or have a large propagation loss in the LC. The LC communication evaluation unit 17 is in a situation where the line is tight (that is, the traffic that is about to flow is not large enough for the line that can be transmitted and received in the wireless section, the number of user terminals that are accessing, the signal power A situation (caused by an increase in access and an increase in interference of distant user terminals). Specifically, the time during which the line is tight, the identification information / position / location information of the user terminal that is tight with the LC line, the identification information of the second mobile communication base station apparatus where the line is tight, At least one of them is output to the UC radio environment measurement control signal generator 14. The UC radio environment measurement control signal generation unit 14 selects the user terminal 2 that measures the input condition, and generates a UC radio environment information measurement control signal including the condition. By estimating the UC radio environment information together with the offload request, the UC radio environment information in the UC radio environment information storage unit 5 is not only for estimating the UC communication quality, but also for the shared frequency band base station. It can also be used for 3 new stations. That is, when the communication status in the UC does not satisfy the request for the offload, the user experience can be improved by placing a new shared frequency band base station 3 at this position.

(5) Periodic and complementary information measurement / collection In the fifth example, in order to improve the accuracy of information in the UC wireless environment information storage unit 5, UC wireless environment information is measured. For example, when trying to update the latest information as much as possible with respect to the date, day of the week, time, periodically updating the list of identification information in the UC, or when it is desired to measure information comprehensively for position information, Measurement is performed for necessary time, identification information, and position information. The first mobile communication base station selects a UC measurement user terminal from the user terminals 2 with which communication has been established, and measures UC radio environment information at a specific position periodically or at a specific time. Or specify information measurement and notification. In the fifth example, when UC wireless environment information is collected under the first to fourth conditions, information on time / position / identification information that can be determined to be insufficient as a result is clarified. UC radio environment information measurement conditions can be used as measurement conditions. Or, for special events such as concerts, sporting events, festivals, disasters, traffic troubles, weather, etc., by measuring the information on the shared frequency band when the distribution and behavior of the user terminal 2 changes significantly, It is possible to accurately grasp the UC radio environment and evaluate the communication quality in the UC and the shortage of the shared frequency band base station 3 at the time of the event. For this purpose, special event information can be input from the external network and input to the UC radio environment information storage unit 5 and the UC radio environment measurement control unit 14 via the information input / output unit 13.

  In the first to fifth examples described above, the condition determination may be notified as the user terminal 2 performs, or the mobile communication base station 1 determines the condition based on the received signal from the user terminal 2. Then, it may be instructed to immediately measure the shared frequency band or collect the UC radio environment information, or the mobile communication base station 1 determines the condition based on the received signal from the user terminal 2 and determines the UC While transmitting the radio environment measurement control signal, the user terminal 2 may also determine the condition from the received UC radio environment measurement control signal. Further, a plurality of first to fifth examples may be combined, or measurement conditions and conditions for collecting information measured from the user terminal 2 may be individually set.

  Next, the configuration of the user terminal 2 shown in FIG. 1 will be described with reference to FIG. FIG. 3 is a block diagram showing a configuration of the user terminal 2 shown in FIG. When the configuration of the user terminal 2 is described with reference to FIG. 3, the well-known functions and configurations that the user terminal normally has are described and illustrated in the configuration unless directly related to the description of the present invention. Omitted.

  In FIG. 3, reference numeral 21 denotes an LC antenna corresponding to a channel in the licensed frequency band. Reference numeral 22 denotes an LC transceiver that transmits and receives a radio signal in the licensed frequency band. Reference numeral 23 denotes an information signal input / output unit that inputs and outputs information signals. Reference numeral 24 denotes a UC antenna corresponding to a channel in the shared frequency band. Reference numeral 25 denotes a UC transmission / reception unit that transmits / receives a radio signal in the shared frequency band. Reference numeral 26 denotes a UC radio environment information extraction unit that extracts the measured UC radio environment information and the UC radio environment measurement signal received in the LC. Reference numeral 27 denotes a UC information feedback signal generation unit that converts the obtained UC radio environment information into a form suitable for feedback on the LC line. Here, when LC and UC correspond to a plurality of frequencies, a plurality of LC transceivers 22 and LC antennas 21, and UC transceivers 25 and UC antennas 24 may be provided.

  The user terminal 2 communicates with the mobile communication base station 1 via the LC antenna 21 in the licensed frequency band. When receiving a signal from the mobile communication base station 1, the LC transmitter / receiver 22 acquires data information transmitted by the user terminal through processing such as down-conversion, synchronization, and decoding, and outputs the data information to the information signal input / output unit 23. If a UC radio environment measurement control signal instructing measurement of a channel (UC) in a shared frequency band that does not require a license is detected, it is output to the UC radio environment information extraction unit 26.

  The UC radio environment information extraction unit 26 acquires the measurement conditions of the shared frequency band and the collection conditions (notification conditions) of the measurement information. If the measurement conditions match the current state of the user terminal 2, the corresponding information is input to the information signal. Measurement is performed from the output unit 23 or the UC transceiver unit 25. If the function block that performs transmission / reception of the shared frequency band is not turned on, the UC wireless environment information extraction unit 26 may instruct the power supply to be turned on. The UC radio environment information extraction unit 26 can directly acquire information such as a received power level and a radio signal occupancy rate that can be measured by the UC transmission / reception unit 25 from the UC transmission / reception unit 25. RCPI, RSNI, RSSI, RSRP, RSRQ, channel utilization rate, BSS load, transmission wireless terminal identification information, transmission destination identification information, multi-user simultaneous transmission information that can be read from the control signal part of the received frame , Guard interval length, packet length, information included in broadcast signal transmitted by shared frequency band base station, frequency bandwidth information that can be utilized or utilized, RTS / CTS signal utilization, packet bit amount, Information on frame aggregation, radio signal occupancy, etc. may be acquired.

  The UC wireless environment information extraction unit 26 can obtain necessary information from the information signal input / output unit 23 in order to determine whether the measurement condition indicated by the UC wireless environment measurement control signal is satisfied. For example, the information signal input / output unit 23 includes not only information related to communication in the licensed frequency band and the shared frequency band, but also time information such as date / day of the week / time, user terminal position information, contract form, function, various sensors, applications Information that is not directly related to communication in the shared frequency band, such as information, information generated by an application, and user behavior information, can also be output to the UC wireless environment information extraction unit 26.

  When necessary information is accumulated in the UC radio environment information extraction unit 26, it is output to the UC information feedback signal generation unit 27, and the UC radio environment information is converted into an appropriate form designated by the UC radio environment measurement control signal. A UC information feedback signal is generated and transmitted to the mobile communication base station 1 by LC through the information signal input / output unit 23, the LC transceiver unit 22, and the LC antenna 21 at an appropriate timing. When the collection condition is designated as an appropriate timing, it is determined whether the UC wireless environment information extraction unit 26 satisfies the collection condition. If the collection condition is satisfied, the information signal input / output unit is input to the UC information feedback signal generation unit 27. The output to 23 is instructed. If the collection condition is not specified or the collection condition is the same as the measurement condition, the UC information feedback signal is immediately output to the information signal input / output unit 23 and moved via the LC transceiver unit 22 and the LC antenna 21. It is transmitted to the communication base station 1.

  The UC radio environment information extraction unit 26 is acquired by the UC transmission / reception unit 25 using information that may be conditioned from the mobile communication base station 1 so that it is not necessary to measure the signal in the shared frequency band again. The signal may be stored in advance. For example, the location information of the user terminal 2, the measured time information, the identification information corresponding to the measured information are stored, the UC radio environment measurement control signal is received, and the UC radio environment information extraction unit 26 extracts this signal. In this case, it is possible to select information that meets the conditions from the information of the shared frequency band that has already been stored, and output the selected information to the UC information feedback signal generation unit 27.

  In the UC radio environment measurement control signal, when it is instructed to check whether or not the surrounding user terminals can be detected in the shared frequency band, a transmission signal that can identify the identification information of the user terminal itself at a predetermined timing, In addition to transmitting on the frequency channel specified in the shared frequency band, transmission information in the shared frequency band transmitted by other user terminals is measured, and identification information is extracted. At this time, in order to avoid packet collision, the mobile communication base station 1 may designate the transmission timing of the user terminal 2 or the measurement time condition may be designated.

  Further, the UC wireless environment information extraction unit 26 may have a function of detecting an abnormality in UC communication. UC communication abnormal conditions are preliminarily set in a user terminal at a certain packet error rate or less, a delay time or more, a line disconnection frequency of a certain value or more, the disappearance of a notification signal such as a Beacon signal, or communication using a signal included in the Beacon signal. Abnormal information and loss of connection can be determined. The communication abnormality condition may be stored in advance in the user terminal, or may be updated or notified from the mobile communication base station.

  Next, the control operation of the above-described wireless communication system will be described with reference to FIG. FIG. 4 is a flowchart showing a control operation of the radio communication system in which the mobile communication base station determines the measurement of the UC radio environment information and instructs the user terminal 2 to measure the UC radio environment information in the present embodiment. The control operation shown in FIG. 4 is used, for example, when the mobile communication base station can determine the measurement conditions of the UC radio environment information, or as in the fifth example described above, to measure the UC radio environment information periodically. Can do. Alternatively, the mobile communication base station performs the determination by obtaining information necessary for determining the measurement conditions from the user terminal through the LC line for an LC active user terminal that performs communication on the LC line, which will be described later. Can also help. When the UC radio environment measurement control signal generation unit 14 determines the UC radio environment measurement condition in the mobile communication base station 1 (step S1), the UC radio environment measurement control signal generation unit 14 generates a UC radio environment measurement control signal, and the LC Is transmitted to the user terminal 2 (step S2). The user terminal 2 receives the transmitted signal via the LC antenna 21 and the LC transmitter / receiver 22, and acquires a UC radio environment measurement control signal (step S3). Then, the user terminal 2 determines whether the information necessary for the measurement condition is already stored in the UC wireless environment information extraction unit 26 (No) or stored (Yes) (step S4).

  If not stored, the wireless environment information of the shared frequency band is measured after performing necessary processing such as turning on the power of the transmitting / receiving device of the shared frequency band (step S5). In the case of Yes in step S4 or after the measurement of the wireless environment in step S5, the user terminal 2 converts the wireless environment information of the shared frequency band into a feedback signal by LC and is instructed by the UC wireless environment measurement control signal. Transmit to the mobile communication base station 1 under the collection conditions (step S6). Here, when the collection condition is not designated, it may be transmitted immediately. In response to this, the UC radio environment information storage unit 5 stores the radio environment information of the shared frequency band from the fed back signal (step S7). In addition, when the measurement is finished and the state is step S6, the information may be discarded when moving to another mobile communication base station 1 without satisfying the condition for collecting the measured information. Further, after the connection with the other mobile communication base station 1 is established, if the collection conditions are satisfied, the measurement information is notified, and the other mobile communication base station 1 sends the UC radio environment information storage unit 5 via the network. Collect measured information.

  Next, an example in which the user terminal 2 determines the given measurement condition and measures the UC wireless environment information will be described. Here, the notification condition (collection condition) of the UC radio environment information by LC is the same as the measurement condition. Here, two examples of the subordinate user terminals existing in the communicable area are shown in the idle state and the active state in the LC. The LC active user terminal 2 is a user terminal 2 that is continuing to transmit or receive data packets, and the LC idle user terminal 2 performs communication to establish communication when entering the communicable area. It is a user terminal 2 that has not moved to another area after that, but currently does not communicate user data in the LC.

  Similarly, from a state in the unlicensed band (UC), a user terminal 2 that is continuing to transmit or receive data packets in the shared frequency band, a user terminal 2 that is UC active, and a circuit power source for transmitting and receiving UC signals UC idle user terminal 2 which is ready for transmission / reception but not communicating, and user terminal 2 which is not powered on for the circuit for transmitting / receiving UC is user terminal 2 which is UC off. It is defined as

  Since it is communicating with the LC active user terminal 2, the UC wireless environment information is added to the user data being communicated compared to the case where the communication is performed for collecting the UC wireless information from the LC idle user terminal 2. As a result, the overhead for the UC wireless environment information can be kept small. For this reason, by transmitting the UC radio environment measurement control signal to the LC active user terminal 2, it can be expected to collect UC radio environment information with a small load on the LC line.

  Next, a processing operation for acquiring UC wireless environment information for acquiring wireless environment information from the LC active user terminal 2 will be described. FIG. 5 is a flowchart showing a processing operation for transmitting a UC radio environment measurement control signal to the LC active user terminal 2 and acquiring UC radio environment information. When the LC active user terminal is a target, part or all of the determination of the measurement conditions of the UC radio environment information can be performed in the mobile communication base station 1. Hereinafter, first, an example of determination at the user terminal will be shown, and a case where a part or all of the determination is performed at the mobile communication base station will be described using the same FIG. Hereinafter, the flow for determining the measurement conditions in all the user terminals 2 is flow A, the flow for determining the measurement conditions for some mobile communication base stations 1 is flow B, and the flow for determining the measurement conditions for all mobile communication base stations 1 This will be described as flow C.

  First, the flow A will be described. The mobile communication base station 1 starts communication with the user terminal 2 (step S11), and transmits a UC radio environment measurement control signal using the LC to the user terminal 2 communicating with the LC (step S12). The user terminal 2 acquires, from the received UC radio environment measurement signal, the measurement conditions of the radio environment information at the UC or the measurement conditions and the collection conditions of the measured information, and specifies the information that these conditions are not related to the communication at the UC If so, it is determined whether the condition is satisfied before using the UC information (step S13). However, it also includes determination of information that can be obtained without turning on the power supply of the UC transmission / reception circuit, such as determination of UC active / idle / off. If the condition not related to UC is not satisfied, the processing operation is waited until the condition is satisfied.

  Next, when a condition not related to UC is not specified, or when a condition not based on information to be acquired by UC is satisfied, the power is turned on if the power of the UC transmission / reception apparatus is not turned on (step S14). If preparation for UC communication is completed, it is determined whether the measurement conditions of the UC wireless environment information are satisfied, or whether there is information that has not been measured and reported under the satisfied conditions (step S15). If the condition is met or has a corresponding measurement result (determination: Yes), the measurement on the UC radio environment or the stored measurement result is called (step S16).

  Next, the measured UC radio environment information is converted into feedback information to the mobile communication base station 1 and transmitted to the mobile communication base station according to the designated collection condition (step S17). The UC radio environment information storage unit 5 (Step S18). When the user terminal 2 transmits the UC wireless environment information, it is further determined whether continuous measurement is designated by the UC wireless environment measurement control signal (step S19). The UC radio environment measurement signal can specify the measurement conditions so as to correspond to the collection of UC radio environment information multiple times, such as when the UC radio environment is periodically measured and there are a plurality of measurement conditions.

  On the other hand, if the measurement is completed once and measurement results are collected (determination: No), the process is terminated. If the condition needs to be continuously determined, the process returns to step S13 (determination: Yes). In step S15, when the measurement condition is not satisfied and the measurement result corresponding to the measurement condition is not stored (determination: No), the conditions other than the UC channel in step S13 are satisfied. While waiting until the condition of UC communication is satisfied. For example, if time is specified in the measurement condition, it is determined that the condition is not satisfied once in step S15, and if there is a long time until the next measurement time and communication by UC is not required at all, step S13 is performed. In, the power supply of the UC transceiver can be turned off. When the collection conditions of the UC wireless environment information measured in step S17 are not immediately satisfied, it is possible to wait in step S17 or to proceed in parallel with the process of returning to step S13 and continuing the measurement.

  The determination based on conditions other than UC in step S13 is, for example, the communication status in the LC with the user terminal 2, the identification information of the mobile communication base station detectable in the LC, the location information of the user terminal 2, mobility information, time information, The determination can be made based on the function of the user terminal, the application being used, and the application that can be used. Further, the determination in step S15 is determination performed using UC information, communication conditions with the shared frequency band base station 3, identification information of the communicating shared frequency band base station 3, and detectable shared frequency band base Station identification information, broadcast information from the shared frequency band base station, radio resource tightness information in the shared frequency band, detection of communication abnormality in the UC, and the like can be used. Either the determination in step S13 or the determination in step S15 may not be used.

  Next, the flow B in which the mobile communication base station 1 performs the determination in step S13 in FIG. 5 and the flow C in which both the determinations in step S13 and step S15 are performed will be described. When the determination is performed at the mobile communication base station, information necessary for determination for communication with the user terminal 2 is acquired from the user terminal 2.

  In the flow B, an example in which the communication base station apparatus 1 determines only step S13 first is shown. In FIG. 5, step S12 shown in parentheses is not performed. After starting communication with the user terminal 2 and becoming active in the LC, necessary information is collected from the user terminal 2 in step S13. However, this is not the case when there is no need to collect information from the user terminal 2, such as time information, information related to LC communication, and event information other than communication. When information other than UC communication is a measurement condition from information collected from the user terminal 2 or information held by the mobile communication base station 1, a UC radio environment measurement control signal is generated and transmitted to the user terminal 2. To do. That is, step S12 enters between step S13 and step S14. Hereinafter, it is basically the same as the case where the determination is made at the user terminal 2, but when the measurement condition is not satisfied at step S15, the process returns to step S13, but the user terminal 2 determines step S15 until it is satisfied. Become. When the mobile communication base station 1 determines that the conditions other than the UC no longer satisfy the measurement conditions, the mobile communication base station 1 transmits a UC radio environment measurement condition signal again to notify the user terminal 2 that the process is to be terminated. it can.

  Next, the flow C will be described. Even in the flow C, step S12 shown in parentheses in FIG. 5 is not performed. After starting communication with the user terminal 2 and becoming active in the LC, necessary information is collected from the user terminal 2 in step S13. If the information collected from the user terminal 2 or the information held by the mobile communication base station 1 is information other than UC communication is the measurement condition, the power of the UC transmitter / receiver is supplied to the user terminal 2 if necessary. It is instructed to insert (step S14). The state of the UC transmission / reception circuit may be collected in advance by the communication base station. If unnecessary, step S14 may not be performed. When preparation for information acquisition at the UC is completed, information necessary for determination is collected by communication at the LC using communication at the LC. At this point, it can be said that a part of the UC radio environment information has already been collected (similar to proceeding to step S16 without performing the determination in step S15). In the flow C, the acquired UC wireless environment information can be used as a trigger for acquiring more detailed UC wireless environment information.

  In order to reduce the load on the line, it is desirable to collect as little UC radio environment information as possible. For example, the observed identification information of the shared frequency band base station 3 and the corresponding received signal level may be notified. When the mobile communication base station apparatus determines that the measurement conditions in the UC radio environment are satisfied, a UC radio environment measurement control signal is transmitted, and the flow from step S16 is performed. That is, the transmission of the UC radio environment measurement control signal (step S12) is performed between step S15 and step S16. In performing the flow after step S16, the wireless environment information may be acquired by the flow after step S2 in FIG. This is because the flow C does not determine the measurement at the user terminal 2 but only receives the measurement instruction, so the determination in step S19 is not assumed to be a continuous measurement, and always ends with determination: No. For this reason, it is almost the same as the flow of FIG.

  In the flow A to the flow C described with reference to FIG. 5, even if the LC is not active on the way, the processing operation can be continued in the case of the determination flow in the user terminal 2. When the user terminal 2 moves to a cell of another mobile communication base station 1, the measurement conditions are discarded and the process ends. However, in the case where the measurement is completed and the measurement information is collected (notified) in the state of step S17, the information collected by other mobile communication base stations 1 is also stored in the UC wireless environment information via the network. If the data can be collected by the unit 5, the process may not be terminated, and the measurement information may not be discarded until the timing that is the collection condition in the user terminal 2, and transmission may be awaited. Moreover, you may designate with a UC radio | wireless environment measurement control signal so that the measurement result which it has may be notified in communication of communication establishment with another mobile communication base station.

  FIG. 6 is a flowchart showing a processing operation for collecting UC wireless environment information from the user terminal 2 in an idle state in the LC. The current information for the user terminal 2 in the LC idle state cannot be obtained by the mobile communication base station 1.

  First, an LC idle user terminal that transmits a UC radio environment measurement signal is determined (step S21). Information that can be used for determination includes the contract form of the user terminal 2, the function of the user terminal 2, information collected during the LC active communication (the second mobile communication base station 4 that was last accessed) Identification information, etc.) and information collected from the shared frequency band base station 3 collected via the network. A required number of user terminals 2 may be determined at random. When the user terminal 2 is determined, a UC radio environment control signal is generated, and LC communication is started and transmitted (step S22).

  Step S23 and subsequent steps are the same as step S13 and subsequent steps shown in FIG. The user terminal 2 acquires, from the received UC radio environment measurement signal, the measurement conditions of the radio environment information at the UC or the measurement conditions and the collection conditions of the measured information, and specifies the information that these conditions are not related to the communication at the UC If so, it is determined whether the condition is satisfied before using the UC information (step S23). If the condition not related to UC is not satisfied, the flow is stopped until the condition is satisfied. If there is no designation of a condition not related to UC, or if a condition that does not depend on information to be acquired by UC is satisfied, the power is turned on if the UC transmitting / receiving apparatus is not turned on (step S24).

  Next, when preparation for UC communication is completed, it is determined whether the measurement conditions of the UC wireless environment information are satisfied, or whether there is information that has not been measured and reported under the satisfied conditions (step S25). If the condition is met or has a corresponding measurement result (determination: Yes), the measurement on the UC radio environment or the stored measurement result is called (step S26). Then, the measured UC radio environment information is converted into feedback information to the mobile communication base station, and transmitted to the mobile communication base station according to the designated collection condition (step S27), and stored in the UC radio environment information storage unit 5 (Step S28).

  Next, when the user terminal 2 transmits the UC wireless environment information, it is further determined whether continuous measurement is designated by the UC wireless environment measurement control signal (step S29). The UC radio environment measurement signal can specify the measurement conditions so as to correspond to the collection of UC radio environment information multiple times, such as when the UC radio environment is periodically measured and there are a plurality of measurement conditions. If the measurement is completed once and measurement results are collected (determination: No), the process ends. Otherwise, the process returns to step S23. In step S25, when the measurement condition is not satisfied and the measurement result corresponding to the measurement condition is not stored (determination: No), the conditions other than the UC channel in step S23 are satisfied. While waiting until the condition of UC communication is satisfied.

  Even in the flow described with reference to FIG. 6, when moving to another mobile communication base station 1 in the state of step S17 of collection (notification) of measurement information, the measurement information can be discarded, or via the network, When the data can be collected in the UC wireless environment information storage unit 5, when the collection conditions are satisfied in another mobile communication base station, the measurement information is notified and stored in the UC wireless environment information storage unit 5 via the network. You can also.

  In this way, in a mobile communication system that uses a license band in a single system, mobile communication is used in order to make advanced use of a shared frequency band wireless system line that uses a shared frequency band (unlicensed band) in which multiple systems coexist. From the base station, the information collection method of the shared frequency band can be controlled by the mobile station, and information on the communication quality supported in the shared frequency band can be acquired in detail. Based on the shared frequency band information collected from the mobile communication base station or the mobile communication base station and the shared frequency band base station, the spatial or temporal conditions for collecting the radio environment information of the shared frequency band and the mobile station to collect the information are determined. As a result, it is possible to acquire information necessary for estimating the communication quality of the shared frequency band while efficiently collecting information of the shared frequency band.

  Note that the UC radio environment measurement control signal generation unit 14 designates the user terminal 2 that confirms whether or not each other's signal can be detected in the shared frequency band as the correlation check group as the UC radio environment measurement control signal, and the user terminal 2 When a correlation check group is specified in the UC radio environment measurement control signal, a radio signal including its own identification information is transmitted to determine whether the identification information of other wireless terminals in the correlation check group is detected You may make it do. Thus, by determining whether the user terminals 2 can detect each other, it is possible to more accurately simulate the influence of the hidden terminal problem by the following second utilization method.

  Further, the UC radio environment measurement control signal generation unit 14 performs the mobile communication base station 1 or the second mobile communication when a connection establishment or release process with the mobile communication base station 1 or the second mobile communication base station 4 is performed. The base station 4 may generate a UC radio environment measurement control signal that requests the user terminal 2 to measure radio environment information in the shared frequency band.

  In addition, the UC radio environment measurement control signal generation unit 14 determines the shared frequency band of the user terminal 2 when the position information of the user terminal 2 does not change for a certain time or when the user terminal 2 indicates a stationary state. A UC radio environment measurement control signal for requesting measurement of radio environment information may be generated.

  An example of utilization of the UC radio environment measurement control signal generation unit 14, the UC radio environment information storage unit 5, and the UC communication status evaluation unit 16 will be described below. In the first utilization method, the user terminal 2 under the mobile communication base station 1 grasps in real time which shared frequency band base station 3 is performing user data communication, and communicates with the shared frequency band base station 3. By correcting the number of user terminals in real time, it is possible to notify the user terminal of the selection policy of the shared frequency band base station 3, designation of switching, and line state information.

  In the first utilization method, when the user terminal 2 enters the communication cell of the mobile communication base station 1 and establishes a connection for authentication, registration, etc., the shared frequency band base station 3 When establishing a connection to perform data frame communication, a UC radio environment measurement control signal set to notify the mobile communication base station of the identification information of the shared frequency band base station as UC radio environment information is transmitted (measurement). Condition: connection establishment with shared frequency band base station 3, collection condition: connection establishment with shared frequency band base station 3). When the user terminal 2 establishes a connection with the shared frequency band base station 3 by switching or using it together, the user terminal 2 notifies the mobile communication base station 1 of the identification information, and the information signal input / output unit 13 sends the UC radio environment information. Collected in the storage unit 5.

  The UC radio environment information storage unit 5 manages the number of user terminals 2 exchanging data frames for each identification information of the shared frequency band base station 3. The UC communication status evaluation unit 16 determines the current line load of the shared frequency band base station 3 from the number of user terminals 2 belonging to the shared frequency band base station 3, and the user terminal determines the connection destination in the shared frequency band. The accuracy of information such as a policy for the user terminal 2 or identification information of the shared frequency band base station 3 to be connected to the user terminal 2 or transmission of UC radio environment information in response to a request from the user terminal Can be increased.

  Furthermore, in the first utilization method, by adding the information of the corresponding received power level in addition to the identification information, it is possible to estimate the tightness state of the radio resource of the shared frequency band base station with higher accuracy. That is, it is possible to determine that the user terminal 2 accessing the UC at a low reception power level consumes radio resources, and evaluate the consumption state of the radio resources. This is because the shared frequency band base station 3 to which the user terminal 2 has established a connection at a low signal level communicates the same amount of data bits, but has a low physical layer data rate, a long packet length, a high packet error rate, etc. This is because it is easy to take the time to send the same bit, and the tight situation of radio resources becomes more serious.

  Further, in the first utilization method, the number of wireless terminals being accessed, backhaul information, wireless resource tightness information, and the like included in a broadcast signal such as Beacon transmitted from the shared frequency band base station 3 are further added to the user. Information is acquired in more detail by causing the terminal 2 to acquire the information and collecting it through the backhaul line. The information in the broadcast signal has a merit that it is difficult to secure real-time property, but information including access of a wireless terminal that does not have a connection with the mobile communication base station 1 can be obtained. In terms of real-time characteristics, by adding access destination notification information collected for each user terminal, a more accurate understanding of the UC wireless environment can be realized.

  In the second utilization method, in the frequency channel that can be used for communication by the shared frequency band base station 3 or the shared frequency band base station 3 and the user terminal 2 respectively, the identification information of the detectable wireless terminals is collected, By determining and organizing the detection relationship in the UC wireless environment information storage unit 5, the estimation accuracy of the UC wireless communication quality estimated by the UC communication status evaluation unit 16 is increased.

  In the second utilization method, in the cell of the mobile communication base station 1, a hidden terminal that is particularly problematic in the shared frequency band is obtained by grasping which radio terminal is detecting which radio terminal in the shared frequency band. It is possible to reduce throughput reduction due to problems and exposed terminal problems. The mobile communication base station 1 can be detected by the broadcast signal of the shared frequency band base station 3 in the cell of the mobile communication base station 1 when the user terminal 2 enters the communication cell and establishes a connection for authentication / registration. When the identification information of another shared frequency band base station 3 is notified, the identification information of the transmission source of the broadcast signal and the identification information of the shared frequency band base station detected by the identification information are moved as UC radio environment information A UC radio environment measurement control signal designating notification to the communication base station is transmitted (<example> measurement condition: another shared frequency band base station 3 detected by a notification signal from the shared frequency band base station 3) If the identification information is notified, the collection condition: at the start of data frame communication in the next LC).

  When the user terminal 2 detects and acquires the notification signal, the identification information of the shared frequency band base station 3 and the identification information detected from the identification information are stored. The measurement result can be collected when the user terminal 2 performs data frame communication in the next LC. In the UC radio environment measurement signal, specify the condition of LC communication quality and distance (propagation loss) with the mobile communication base station in the collection conditions, and specify the time of communication with the second mobile communication base station that can expect high throughput May be. The collected information is output from the information signal input / output unit 13 to the UC wireless environment information storage unit 5.

  The UC radio environment information storage unit 5 manages the detectable identification information for each identification information of the shared frequency band base station 3, and organizes and stores the detection relationship between the shared frequency band base stations 3. The UC communication status evaluation unit 16 evaluates the risk of throughput reduction due to the hidden terminal problem and the exposed terminal problem from the mutual relationship of the identification information in the UC wireless environment information storage unit 5, and the user terminal determines the connection destination in the shared frequency band. The accuracy of information such as a policy for determination, or specification of identification information of the shared frequency band base station 3 to be connected to the user terminal, or transmission of UC radio environment information according to the request of the user terminal is determined. Can be increased.

  Further, in the second utilization method, the measurement condition and the measurement contents are newly made to measure the identification information of the shared frequency band base station 3 that can be detected by the user terminal 2 when the connection with the shared frequency band base station 3 is established. In addition, by collecting, identification information that can be detected by the user terminal 2 accessing the shared frequency band base station 3 is collected and compared with identification information that can be detected by the shared frequency band base station 3 that is the access destination The UC radio environment information can be reinforced by evaluating the risk of the hidden terminal problem or detecting the same identification information as the user terminal 2 even in the corresponding shared frequency band base station 3 with a high received power level. .

  In addition, when the user terminal 2 creates feedback information to the mobile communication base station 1, the user terminal 2 includes the position information at the time of measurement of the own user terminal or includes the position information of the shared frequency band base station 3. It is also possible to add position information to the identification information in the information storage unit 5, make the radio environment information more detailed, and easily estimate the UC radio environment information for the position information of the user terminal.

  Further, in the user terminal 2, by using the identification information of the destination terminal or the identification information of the transmission source described in the control signal of the data frame received by the UC, the occupation rate of the radio resource is evaluated for each identification information, thereby obtaining the identification information. Corresponding traffic conditions can also be collected. At this time, by including the time information at which the measurement was performed, it is possible to obtain information on traffic fluctuation with respect to the identification information.

  In addition, a traffic model for time information such as date, day of the week, and time can be constructed from the traffic information in the UC that can be estimated by collecting information via the backhaul of the user terminal 2 and the shared frequency band base station. In addition, the UC communication status evaluation unit 16 can simulate packet transmission in the shared frequency band and estimate the transmission quality in more detail from the condition that the traffic model and the identification information can be detected from each other.

  Next, the effects of the present invention will be described with reference to FIGS. FIG. 7 shows a link indicating whether or not the shared frequency band base station 3 (AP in the figure) detected by the user terminal 2 indicated by a horizontally long ellipse and the shared frequency band base station 3 can detect each other. FIG. The user terminal 2 or the shared frequency band base station 3 connected with each other in a straight line indicates that identification information can be detected from each other.

  It can be constructed from the identification information collected from the user terminal 2 or the shared frequency band base station 3 whether or not they can be detected from each other obtained in FIG. It shows that there are four shared frequency band base stations 3 communicating with different frequency channels from AP1 to AP4 around the user terminal 2. The usage status of the shared frequency band of all the wireless terminals shown in FIG. 7 affects the communication quality between the user terminal 2 and the shared frequency band base station that is the connection destination. The more accurately the usage status of the wireless environment at that time and at that location is, the more accurate the estimation accuracy of the throughput characteristics that the user terminal 2 can actually obtain.

  FIG. 8 shows a cumulative probability distribution (CDF: Cumulative Distribution Function) of throughput obtained by the user terminal 2 when the usage statuses of radio resources of all links are randomly given. In FIG. 8, “Data packet occupancy ratio” is the ratio of the actually obtained throughput to the data rate in the physical layer. That is, in a link where a throughput of 100 Mbps can be obtained in the physical layer and the execution throughput is 10 Mbps, the Data packet occupancy ratio is 0.1.

  The simulation result shown in FIG. 8 shows that the distribution of throughput that can be obtained by the user terminal 2 can change greatly when the traffic generated in all the links is random. Although it can be confirmed that high throughput can be obtained on average by connecting to AP3, there are conditions for high throughput in AP1 and AP4 as well. Here, the traffic generated for the link is set randomly from 0 to 1 in the Data packet occupancy ratio, but the UC communication status evaluation unit 16 estimates the traffic amount for the link, It becomes possible to evaluate the communication quality of the more probable shared frequency band.

  As explained above, in order to cope with the rapid increase in traffic in the future, when using communication in the frequency band where multiple systems coexist in addition to communication in the licensed frequency band, the communication quality of the shared frequency is significantly reduced depending on the communication environment. Therefore, it is necessary to grasp in detail the wireless environment information using the shared frequency. In this embodiment, efficient and detailed wireless environment information is acquired by designating conditions for collecting wireless environment information in the shared frequency band by communication in the licensed frequency band. With this configuration, it is possible to improve the estimation accuracy of the communication quality of the shared frequency band that is actually obtained by the user terminal, and as a result, it is possible to apply a condition that increases the throughput for the user terminal.

  You may make it implement | achieve the mobile communication base station 1 and user terminal 2 in embodiment mentioned above with a computer. In that case, a program for realizing this function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be read into a computer system and executed. Here, the “computer system” includes an OS and hardware such as peripheral devices. The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory inside a computer system serving as a server or a client in that case may be included and a program held for a certain period of time. Further, the program may be for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in the computer system. It may be realized using hardware such as PLD (Programmable Logic Device) or FPGA (Field Programmable Gate Array).

  As mentioned above, although embodiment of this invention has been described with reference to drawings, the said embodiment is only the illustration of this invention, and it is clear that this invention is not limited to the said embodiment. is there. Therefore, additions, omissions, substitutions, and other modifications of the components may be made without departing from the technical idea and scope of the present invention.

  Share the mobile station base station by notifying the user terminal of conditions including time and / or space for acquiring the radio information of the shared frequency band, and acquiring the radio information of the shared frequency band of any condition It can be applied to applications where it is essential to evaluate the communication quality of the frequency band and to realize a mobile communication system that efficiently utilizes the shared frequency band in the licensed frequency band.

  DESCRIPTION OF SYMBOLS 1 ... Mobile communication base station, 11 ... LC antenna, 12 ... LC transmission / reception part, 13 ... Information signal input / output part, 14 ... UC radio | wireless environment measurement control signal generation part, 16. ..UC communication status evaluation unit, 17 ... LC communication evaluation unit, 2, 2-1 to L ... User terminal, 21 ... LC antenna, 22 ... LC transmission / reception unit, 23 ... Information signal input / output unit, 24 ... UC antenna, 25 ... UC transmission / reception unit, 26 ... UC radio environment information extraction unit, 27 ... UC information feedback signal generation unit, 28 ... UC communication Anomaly detection unit, 3, 3-1 to N ... shared frequency band base station, 4, 4-1 to M ... second mobile communication base station, 5 ... UC radio environment information storage unit

Claims (9)

Wireless communication is performed between the wireless terminal device capable of wireless communication using a shared frequency band that does not require a license and a license frequency band that requires a license, and the wireless terminal device using the licensed frequency band. A wireless communication system comprising a mobile communication base station,
The wireless terminal device
A radio environment measurement control signal indicating a measurement condition for measuring specific radio environment information of the shared frequency band and / or an information collection condition for feeding back the measured radio environment information is acquired from the received radio signal of the licensed frequency band A wireless environment measurement control signal extraction unit that
A radio environment measurement unit that measures specific radio environment information of the shared frequency band according to the radio environment measurement control signal,
A wireless environment information transmitter that transmits the measured wireless environment information to the mobile communication base station,
The mobile communication base station is
A radio that generates a radio environment measurement control signal indicating a condition and / or measurement contents for measuring the radio environment information necessary for estimating the communication status of the shared frequency band, and transmits the radio environment measurement control signal to the radio terminal device An environmental measurement control signal generator;
Bei example a radio environment information storage unit for receiving and storing the radio environment information transmitted from the wireless terminal device,
After determining that at least a part of the conditions for measuring the radio environment of the shared frequency band specified by the radio environment measurement control signal is based on the received signal from the radio terminal device and satisfying the condition The wireless environment measurement control signal is transmitted at
A wireless communication system. The wireless environment measurement control signal generator is
In communication with the wireless terminal device in the licensed frequency band, collect at least one of usage application information, mobility information, used wireless access mode information, location information, and communication abnormality information, and the collected information is stored in advance. The radio environment measurement control signal for requesting the radio terminal device to measure radio environment information of the shared frequency band or to collect the measured information when the defined condition is satisfied. The wireless communication system according to 1. The wireless environment measurement control signal generator is
Measured or measured the radio environment of the shared frequency band to detect the establishment or disconnection of the connection with the shared frequency band base station of the wireless terminal device or the detection of a communication abnormality in which the radio communication of the shared frequency band does not satisfy a predetermined condition The radio communication system according to claim 1, wherein the radio environment measurement control signal is added to the radio environment measurement control signal as a condition for collecting information. The wireless environment measurement control signal generator is
Detection of identification information of a specific shared frequency band base station, detection of a broadcast signal of a specific shared frequency band base station, specific position information, measurement of the radio environment of the shared frequency band or collection of information measured at a specific time The wireless communication system according to claim 1, wherein the wireless communication system is added to the wireless environment measurement control signal as a condition to be performed. A second mobile communication base station having a function of transmitting and receiving user data signals in the licensed frequency band to the wireless terminal device;
The wireless environment measurement control signal generator is
Detection of start or end of user data communication with the mobile communication base station or the second mobile communication base station with which the wireless terminal device communicates, or the mobile communication base station or the second mobile communication base with which communication is performed The detection of whether the traffic congestion indicator of a station exceeds a predetermined value is added to the radio environment measurement control signal as a condition for measuring the radio environment of the shared frequency band or collecting the measured information. The wireless communication system according to claim 1. The mobile communication base station is
Obtain external information other than communications that can affect the communication status from the external network,
The wireless environment information storage unit
The wireless communication system according to claim 1, wherein information collected regarding the affected time, position, and identification information is managed for each external information based on the external information. Wireless communication is performed between the wireless terminal device capable of wireless communication using a shared frequency band that does not require a license and a license frequency band that requires a license, and the wireless terminal device using the licensed frequency band. A wireless terminal apparatus in a wireless communication system comprising a mobile communication base station,
A radio environment measurement control signal indicating a measurement condition for measuring specific radio environment information in the shared frequency band or an information collection condition for feeding back the measured radio environment information is acquired from the received radio signal in the licensed frequency band A wireless environment measurement control signal extraction unit that
According to the radio environment measurement control signal, a radio environment measurement unit that measures radio environment information of the shared frequency band;
In accordance with designated information collection conditions, a wireless environment information transmitting unit that transmits measured wireless environment information to the mobile communication base station ;
With
The radio environment measurement control signal includes information for determining whether radio signals to be measured can be detected with each other in the shared frequency band as a correlation confirmation group and measuring whether signals can be detected with each other,
When the correlation check group is specified in the radio environment measurement control signal, a radio signal including its own identification information is transmitted in the shared frequency band, and other radio terminal devices of the correlation check group Determine if identification information is detected,
A wireless terminal device. Wireless communication is performed between the wireless terminal device capable of wireless communication using a shared frequency band that does not require a license and a license frequency band that requires a license, and the wireless terminal device using the licensed frequency band. The mobile communication base station in a wireless communication system comprising a mobile communication base station,
A radio environment measurement control signal indicating a radio environment information necessary for estimating the communication status of the shared frequency band and a measurement condition or an information collection condition for feeding back the measured radio environment information is generated, and the radio terminal apparatus A wireless environment measurement control signal generation unit for transmitting to,
Bei example a radio environment information storage unit for receiving and storing the radio environment information transmitted from the wireless terminal device,
After determining that at least a part of the conditions for measuring the radio environment of the shared frequency band specified by the radio environment measurement control signal is based on the received signal from the radio terminal device and satisfying the condition The wireless environment measurement control signal is transmitted at
A mobile communication base station characterized by the above. Wireless communication is performed between the wireless terminal device capable of wireless communication using a shared frequency band that does not require a license and a license frequency band that requires a license, and the wireless terminal device using the licensed frequency band. A wireless communication method performed by a wireless communication system including a mobile communication base station,
Radio environment measurement indicating the radio environment information that the mobile communication base station needs to measure in order to estimate the communication status of the shared frequency band and the measurement condition or the information collection condition for feeding back the measured radio environment information or both A radio environment measurement control signal generating step of generating a control signal and transmitting the control signal to the radio terminal device;
Radio environment measurement control in which the radio terminal device acquires a radio environment measurement control signal indicating a measurement condition and / or measurement contents for measuring the radio environment information of the shared frequency band from the received radio signal of the licensed frequency band A signal extraction step;
A radio environment measuring step in which the radio terminal device measures radio environment information of the shared frequency band according to a measurement condition specified by the radio environment measurement control signal;
A wireless environment information transmitting step in which the wireless terminal device transmits the measured wireless environment information to the mobile communication base station according to an information collection condition specified by the wireless environment measurement control signal;
The mobile communication base station, possess a radio environment information storing step for receiving and storing the radio environment information transmitted from the wireless terminal device,
After determining that at least a part of the conditions for measuring the radio environment of the shared frequency band specified by the radio environment measurement control signal is based on the received signal from the radio terminal device and satisfying the condition The wireless environment measurement control signal is transmitted at
A wireless communication method.

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