WO2016181587A1

WO2016181587A1 - Wireless communication device and frequency allocation method

Info

Publication number: WO2016181587A1
Application number: PCT/JP2016/001001
Authority: WO
Inventors: 加藤　修
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2015-05-08
Filing date: 2016-02-25
Publication date: 2016-11-17
Also published as: JP2016213687A

Abstract

Provided is a wireless communication device which is capable of improving the utilization efficiency and allocation efficiency of wireless resources for communicating data over a backhaul line. The wireless communication device communicates with other wireless communication devices over a wireless backhaul line on which a plurality of wireless communication modes are mixed and used. The wireless communication device allocates, on the basis of information related to the usage history of wireless frequencies for data communication with the other wireless communication devices, a wireless frequency for data communication with another wireless communication device.

Description

Wireless communication apparatus and frequency allocation method

This disclosure relates to a wireless communication device and a frequency allocation method.

When a terminal performs wireless communication, it is necessary to determine a wireless base station to which the terminal is wirelessly connected and a wireless frequency (wireless channel) used by the terminal for wireless communication. Conventionally, a radio base station selection device that searches for and selects a radio base station and a radio channel using active scan or passive scan is known (for example, see Patent Document 1).

This radio base station selection device creates a connection candidate AP list in which the identification information of the radio base station and the reception level are associated with each radio channel. The radio base station selection device selects one radio base station and a corresponding radio channel having identification information with a reception level exceeding a predetermined threshold and high priority from the connection candidate AP list. The radio base station selection device performs connection processing to the selected radio base station using the selected radio channel.

In recent years, heterogeneous networks have been studied in wireless communication systems in which terminals and wireless base stations are connected to a network (see, for example, Non-Patent Documents 1 to 3).

JP 2010-193088 A

When the technique described in Patent Literature 1 is applied to communication in a plurality of radio base stations connected via a backhaul line, allocation of radio resources for communicating data between the plurality of radio base stations Efficiency and utilization efficiency were insufficient.

The present disclosure has been made in view of the above circumstances, and provides a radio communication device and a frequency allocation method capable of improving allocation efficiency and utilization efficiency of radio resources for communicating data via a backhaul line.

The wireless communication device of the present disclosure communicates with other wireless communication devices via a wireless backhaul line in which a plurality of wireless communication methods are used together. The wireless communication device includes a processor that assigns a radio frequency related to data communication with another wireless communication device based on information on a use history of a radio frequency related to data communication with the other wireless communication device, and an assigned radio frequency. And an antenna that performs data communication with other wireless communication devices.

According to the present disclosure, it is possible to improve allocation efficiency and usage efficiency of radio resources for communicating data via a backhaul line.

FIG. 1 is a schematic diagram illustrating a configuration example of a wireless communication system according to the first embodiment. FIG. 2 is a block diagram illustrating a configuration example of the macro cell base station and the small cell base station in the first embodiment. FIG. 3 is a schematic diagram showing an example of a history database holding information on the use history of radio frequencies used for downlink communication. FIG. 4 is a schematic diagram illustrating an example of a history database that holds information on the usage history of transmission power used for downlink communication. FIG. 5 is a schematic diagram showing an example of a history database holding information on the use history of radio frequencies used for uplink communication. FIG. 6 is a schematic diagram illustrating an example of a history database that holds information on the usage history of transmission power used for uplink communication. FIG. 7 is a flowchart showing a first operation example when the base station assigns a radio frequency to be used for communication via the wireless backhaul line. FIG. 8 is a flowchart showing a second operation example when the base station assigns a radio frequency to be used for communication via the wireless backhaul line. FIG. 9 is a flowchart illustrating a first operation example when the base station determines transmission power used for communication via the wireless backhaul line. FIG. 10 is a flowchart illustrating a second operation example when the base station determines transmission power used for communication via the wireless backhaul line. FIG. 11 is a schematic diagram for explaining a first control example of transmission power by the wireless communication system. FIG. 12 is a schematic diagram for explaining a second control example of transmission power by the wireless communication system. FIG. 13 is a schematic diagram for explaining a third control example of transmission power by the wireless communication system. FIG. 14 is a schematic diagram for explaining a fourth control example of transmission power by the wireless communication system.

Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed description than necessary may be omitted. For example, detailed descriptions of already well-known matters and repeated descriptions for substantially the same configuration may be omitted. This is to avoid the following description from becoming unnecessarily redundant and to facilitate understanding by those skilled in the art. The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the claimed subject matter.

(Background to obtaining one form of the present disclosure)
In 5G (fifth generation mobile communication), a wireless communication system includes a macro cell base station and a small cell base station. And the installation surface density of a small cell base station becomes high, and it is anticipated that efficient laying of a backhaul line becomes important. The backhaul line includes, for example, a line between the small cell base station and the macro cell base station, or between the small cell base station and the backbone network. From the viewpoint of the stability of the communication quality of the backhaul line, an optical line is effective as the backhaul line. On the other hand, a wireless line is effective as a backhaul line from the viewpoint of economics and speed of laying the backhaul line.

In heterogeneous networks, wireless base stations having various wireless standards and cell radii are mixed. Therefore, when the wireless backhaul line (wireless backhaul line) connecting multiple radio base stations is a heterogeneous network, it is assigned to communication between multiple radio base stations connected via the backhaul line It is difficult to suppress communication interference between radio resources (frequency and time) to be used and radio resources used in peripheral terminals and radio base stations. In this case, it is expected that communication interference occurs in various places on the wireless backhaul line as a heterogeneous network, and radio resource allocation processing frequently occurs in order to avoid this communication interference. That is, the allocation efficiency of radio resources was insufficient.

Also, in order to simplify the allocation process of radio resources, it is conceivable to divide and allocate radio resources to each radio base station in advance, but in this case, the utilization efficiency of radio resources decreases.

Hereinafter, a radio communication apparatus and a frequency allocation method capable of improving allocation efficiency and utilization efficiency of radio resources for communicating data via a backhaul line will be described.

(First embodiment)
[Configuration]
FIG. 1 is a block diagram illustrating a configuration example of a wireless communication system 10 according to the first embodiment. The wireless communication system 10 includes a plurality of base stations 200. The plurality of base stations 200 are connected via the wireless backhaul line 20. The plurality of base stations 200 communicate with each other via the wireless backhaul line 20.

The wireless communication system 10 is a heterogeneous network in which the base station 200 has various wireless standards. Base station 200 can also communicate with terminal 100. In the heterogeneous network, different radio communication systems (for example, radio access technology (RAT: Radio Access Technology)) and base stations 200 having different cell radii are mixed. In the heterogeneous network, for example, a plurality of types of radio standards are mixed. In addition, the base stations 200 having different cell radii are superposed on each other, and the RAT includes, for example, information on radio communication standards, radio frequencies, and directivity formation during communication.

This heterogeneous network may not be a C / U separation type network or a C / U separation type network. That is, in the wireless communication system 10, communication related to control data and communication related to user data may be performed by the same base station 200 or may be performed by different base stations 200. For example, when a plurality of terminals 100 existing under different base stations 200 communicate with each other, user data is transmitted via the wireless backhaul line 20.

The base station 200 includes a macro cell base station 200A and a small cell base station 200B. The terminal 100 communicates control data and user data with both the macro cell base station 200A and the small cell base station 200B. The control data includes data related to C (Control) -Plane. The user data includes data related to U (User) -Plane. The user data includes, for example, image data (for example, moving images and still images) and audio data, and may include data with a large amount of data.

C-plane is a communication protocol for communicating control data for call connection and wireless resource allocation in wireless communication. U-plane is a communication protocol for actual communication (for example, video communication, audio communication, and data communication) using assigned radio resources.

The cell radius of the macro cell base station 200A is, for example, 1 km to several km and is relatively large. The RAT that can be adopted by the macrocell base station 200A may be, for example, one type (for example, LTE) or a plurality of types. The cell radius corresponds to the maximum transmission distance of the base station 200.

The cell radius of the small cell base station 200B is 10 to 100 m, for example, and is relatively small. There are various RATs that can be adopted by the small cell base station 200B, and there are a plurality of types. For example, the cell radius may be 100 m or more in a mountainous area, a desert area, or a forest area, or may be larger than the cell radius of the macrocell base station 200A. That is, here, the distinction between the macro cell base station 200A and the small cell base station 200B is not conscious of the size of the cell radius.

In FIG. 1, “MBS” indicates the macro cell base station 200A, “SBS” (Δ) indicates the small cell base station 200B, and “T” indicates the terminal 100. A line surrounding the macro cell base station 200A shows an image of a communicable range by the macro cell base station 200A. A line surrounding the small cell base station 200B shows an image of a communicable range by the small cell base station 200B. The communicable range of the base station 200 is determined according to the position of the base station 200 and the cell radius, for example.

The base station 200 sets a RAT used for communication from a RAT (for example, a radio communication standard or a radio frequency) that can be adopted by the base station 200, and performs radio communication according to the set RAT. The base station 200 can employ one or more RATs.

Wireless communication standards include, for example, LTE (Long Term Evolution), wireless LAN (Local Area Network), DECT (Digital Enhanced Cordless Telecommunication), 3G (3rd generation mobile communication system), 4G (4th generation mobile communication system), 5G (5th generation mobile communication system).

Specific information on RAT includes, for example, the following RAT1 to RAT5. RAT1 is, for example, LTE having a radio frequency band of 700 MHz to 3 GHz. RAT2 is, for example, LTE-Advanced with a radio frequency band of 15 GHz. RAT3 is, for example, wireless LAN communication with a radio frequency band of 5 GHz. RAT4 is, for example, a radio communication system with a radio frequency band of 15 GHz, and is a fifth generation mobile communication system. RAT5 is, for example, a radio communication system (for example, millimeter wave communication) (for example, WiGig) having a radio frequency band of 60 GHz.

FIG. 2 is a block diagram illustrating a configuration example of the macro cell base station 200A and the small cell base station 200B.

The macro cell base station 200A and the small cell base station 200B are connected via the wireless backhaul line 20. The wireless backhaul line 20 includes an uplink 21 and a downlink 22. Uplink 21 is a radio line from small cell base station 200 B to macro cell base station 200 A in wireless backhaul line 20. The downlink 22 is a wireless line that goes from the macro cell base station 200A to the small cell base station 200B in the wireless backhaul line 20. Wireless lines widely include various public lines, mobile phone lines, wide area wireless lines, and the like.

The macro cell base station 200A has one or more small cell base stations 200B existing around the macro cell base station 200A as communication partners. The small cell base station 200B uses one macro cell base station 200A as a communication partner. Since the macro cell base station 200A and the small cell base station 200B are fixedly installed, communication partners of the macro cell base station 200A and the small cell base station 200B are determined in advance.

The macrocell base station 200A includes a processor 250A, a memory 260A, a first interface 201, a first transmission antenna 204, and a first reception antenna 205.

The processor 250A performs various processes and controls in cooperation with the memory 260A. Specifically, the processor 250A implements the functions of the following units by executing a program held in the memory 260A. Each unit includes a first packet generation unit 202, a first radio transmission unit 203, a first radio reception unit 206, a first packet decoding unit 207, and a first radio resource management unit 208.

The memory 260A stores, for example, various data, information, and programs. The memory 260A stores history databases T11 and T12. The memory 260A may be built in the processor 250A. The memory 260A may include a secondary storage device together with the primary storage device. The temporary storage device includes, for example, a RAM (Random Access Memory) and a ROM (Read Only Memory). The secondary storage device includes, for example, an HDD (Hard Disk Memory) and an SSD (Solid State Drive). For example, the memory 260A holds position information (for example, longitude and latitude) of each small cell base station 200B.

FIG. 3 is a schematic diagram showing an example of the history database T11. The history database T11 holds, for each small cell base station 200B wirelessly connected in the past, information on the usage history of the radio frequency used for communication on the downlink 22 with the macro cell base station 200A. The history database T11 may be provided separately for each RAT that can be adopted by the macrocell base station 200A.

The history database T11 holds, for example, information on the small cell base station 200B and information on the use history of radio frequencies in a past fixed period. The information regarding the small cell base station 200B includes identification information (for example, SBS # 1) of the small cell base station 200B. The radio frequency use history information includes information on the radio frequency (for example, f1) used for communication with the small cell base station 200B on the downlink 22, and the amount of communication (communication) using the radio frequency. Data amount) (for example, 784 (MB)).

FIG. 4 is a schematic diagram showing an example of the history database T12. The history database T12 holds, for each small cell base station 200B wirelessly connected in the past, information on the transmission power usage history used for communication with the small cell base station 200B. The history database T12 holds, for example, transmission power usage history information in a past fixed period. The history database T12 may be provided separately for each RAT that can be adopted by the macrocell base station 200A.

The history database T12 holds, for example, information on the small cell base station 200B and information on usage history of transmission power in a past fixed period. The information regarding the small cell base station 200B includes identification information (for example, SBS # 1) of the small cell base station 200B. The transmission power usage history information includes information on transmission power (for example, −6 dBm to −3 dBm) at a radio frequency (for example, f1) used for communication with the small cell base station 200B on the downlink 22 and Information on the frequency (for example, the number of communication) (for example, “2”) of communication with the small cell base station 200B with the transmission power is included.

Here, the transmission power held as the use history may be an average value of transmission power during communication (for example, an average value of time every 3 seconds). In addition, the transmission power held as the usage history may be, for example, a simple total value of power supplied to each antenna described later included in the first transmission antenna 204.

Even if the line status of the wireless backhaul line 20 changes from moment to moment by using the average value of the transmission power as the information of the usage history of the transmission power, the history database T12 has a value in which the influence of the change is smoothed. Can hold.

Note that the average value of the transmission power is roughly determined according to, for example, the radio frequency, transmission distance, ambient environment, antenna height, weather, and radio transmission method. The ambient environment includes information such as whether or not there are buildings or mountains around the base station 200. Weather is considered for rain attenuation. High attenuation occurs when the diameter of raindrops overlaps the wavelength of radio waves and the radio waves are diffused. The higher the radio frequency, the more pronounced rain attenuation. In particular, when using radio waves of 10 GHz or more, it is greatly affected by rain attenuation.

The first interface 201 is a communication interface for connecting the macro cell base station 200A and the host device. For example, when the RAT is LTE, the higher-level device includes SGW (Serving Gateway)), and when the RAT is W-CDMA (Wideband Code Division Multiple Access), it includes SGSN (Serving General packet radio Service).

The first packet generator 202 generates a packet (first transmission packet) to be transmitted to the small cell base station 200B. The first transmission packet includes data on the downlink 22. Data on the downlink 22 (control data and user data) is obtained from, for example, the memory 260, an external device (not shown) such as a storage device or a display device, and various software processing units (not shown).

The first packet generation unit 202 sends information on the usage history of the radio resources for the downlink 22 related to the communication of the first transmission packet to the first radio resource management unit 208. The information on the usage history of the radio resource includes, for example, information on the radio frequency used for communication with the small cell base station 200B and information on the communication amount communicated using the radio frequency.

In the present embodiment, the radio resources segregated in the wireless backhaul line 20 are, for example, a radio frequency used for communication, a part of the radio frequency (a part of the frequency axis, a part of the time axis, or a combination thereof). Including. The part of the frequency axis indicates, for example, a subcarrier frequency or a bundle of a plurality of subcarrier frequencies. The part of the time axis indicates, for example, a time slot or a bundle of a plurality of time slots.

The first wireless transmission unit 203 refers to the history database T12, and based on the past use history of transmission power used for communication with the small cell base station 200B, transmission power used for communication with the small cell base station 200B Is derived, and the initial value of the transmission power is set.

For example, the first wireless transmission unit 203 determines the transmission power having a large usage history (high usage history) as the initial value of the transmission power used for downlink communication. The transmission power with a high usage history may be, for example, the transmission power with the highest frequency accumulated in the history database T12, or may be the transmission power with the frequency not less than the predetermined frequency.

The first wireless transmission unit 203 updates the transmission power usage history information held in the history database T12 based on the transmission power used for communication of the first transmission packet. This transmission power usage history information includes, for example, information on transmission power used for downlink communication with the small cell base station 200B and information on the frequency of communication using this transmission power.

For example, the first wireless transmission unit 203 adds, for example, “1” to the transmission power of the history database T12 that matches the transmission power (current transmission power) related to the transmission of the first transmission packet, Information held in the database T12 is updated.

The first wireless transmission unit 203 transmits the first transmission packet to the small cell base station 200B via the downlink 22 and the first transmission antenna 204. At this time, the first radio transmission unit 203 uses the radio resource allocated by the first radio resource management unit 208 and transmits with the transmission power set by the first radio transmission unit 203.

The first radio transmission unit 203 includes information on radio resources (radio resource allocation information) allocated to communication on the downlink 22 in a control signal and transmits the information to the small cell base station 200B. The radio resource allocation information for the downlink 22 is used at the time of reception in the small cell base station 200B.

The first radio reception unit 206 receives a packet (second received packet) from the small cell base station 200B using the radio resource for the uplink 21 allocated by the first radio resource management unit 208.

The first packet decoding unit 207 decodes the second received packet to obtain second decoded data. The second decoded data includes the uplink 21 data. The data (control data and user data) of the uplink 21 is passed to, for example, the memory 260A, an external device (not shown) such as a storage device or a display device, and various software processing units (not shown).

Further, the data of the downlink 22 includes radio resource allocation information for the downlink 22. The first packet decoding unit 207 sends radio resource allocation information for the downlink 22 to the first radio resource management unit 208.

The first packet decoding unit 207 sends information on the usage history of radio resources related to communication of the second received packet to the first radio resource management unit 208.

The first radio resource management unit 208 refers to the history database T11 and downloads data used for communication with the small cell base station 200B based on the radio frequency usage history used for communication with the past small cell base station 200B. Radio frequency allocation candidates for the line 22 are derived.

For example, the first radio resource management unit 208 determines radio frequencies with a high usage history (high usage history) as radio frequency allocation candidates to be allocated for communication on the downlink 22. The radio frequency with a large usage history may be, for example, the radio frequency with the largest amount of communication accumulated in the history database T11, or may be the radio frequency with the communication data amount equal to or greater than a predetermined amount. Note that a plurality of radio frequency candidates from a candidate with a high priority to a candidate with a low priority may be included.

The first radio resource management unit 208 searches the allocation status of RBs (Resource Blocks) in radio frequency allocation candidates, and determines the presence or absence of unallocated RBs in this radio frequency. When there is an unassigned RB, first radio resource management unit 208 determines that this radio frequency can be assigned. The first radio resource management unit 208 allocates radio resources (radio frequencies and unallocated RBs) that can be allocated as radio resources used for downlink communication with the small cell base station 200B.

The first radio resource management unit 208 acquires radio resource allocation information for the uplink 21 from the first packet decoding unit 207, and stores the radio resource allocation information for the uplink 21 in, for example, the memory 260A for management. . The first radio resource management unit 208 allocates radio resources for the uplink 21 based on the allocation information of radio resources for the uplink 21.

Also, the first radio resource management unit 208 may specify AMC (Adaptive Modulation and Coding) together with RB allocation.

The first radio resource management unit 208 may change the radio frequency and select a new radio frequency from other allocation candidate radio frequencies when the allocation candidate radio frequency cannot be allocated.

In addition, the first radio resource management unit 208 acquires information on the radio resource usage history from the first packet generation unit 202. For example, the first radio resource management unit 208 adds the communication amount included in the usage history information to the radio frequency of the history database T11 that matches the radio frequency included in the acquired usage history information, The information held in the database T11 is updated.

The first radio resource management unit 208 uses the assigned radio resource information for the downlink 22, that is, the radio frequency and RB information used for the downlink 22 communication with the small cell base station 200 B, to the first radio transmission unit. To 203.

The first radio resource management unit 208 uses the assigned radio resource information for the uplink 21, that is, the radio frequency and RB information used for the uplink 21 communication with the small cell base station 200B, to the first radio reception unit. Send to 206.

The small cell base station 200B includes a processor 250B, a memory 260B, a second interface 221, a second transmission antenna 224, and a second reception antenna 225.

The processor 250B performs various processes and controls in cooperation with the memory 260B. Specifically, the processor 250B implements the functions of the following units by executing a program held in the memory 260B. Each unit includes a second packet generation unit 222, a second radio transmission unit 223, a second radio reception unit 226, a second packet decoding unit 227, and a second radio resource management unit 228.

The memory 260B stores, for example, various data, information, and programs. The memory 260B stores history databases T21 and T22. The memory 260B may be built in the processor 250B. The memory 260B may include a secondary storage device together with the primary storage device. The memory 260B holds, for example, position information (for example, longitude and latitude) of the macro cell base station 200A.

FIG. 5 is a schematic diagram showing an example of the history database T21. The history database T21 holds information on the use history of the radio frequency used for communication on the uplink 21 with the macrocell base station 200A. The history database T21 may be provided separately for each RAT that can be adopted by the small cell base station 200B.

The history database T21 holds, for example, information on the usage history of radio frequencies for a certain period in the past. The radio frequency use history information includes information on the radio frequency (for example, f1) used for communication with the macrocell base station 200A and the communication amount (communication data) communicated using the radio frequency in the uplink 21. Information) (for example, 375 (MB)).

FIG. 6 is a schematic diagram showing an example of the history database T22. The history database T22 holds information on the transmission power usage history used for communication with the macrocell base station 200A. The history database T22 holds, for example, transmission power usage history information for a certain period in the past. The history database T22 may be provided separately for each RAT that can be adopted by the small cell base station 200B.

The transmission power use history information includes information on transmission power (for example, −6 dBm to −3 dBm) at the radio frequency (f1) used for communication with the connected macro cell base station 200A, and the macro cell with this transmission power. It includes information on the frequency of communication with the base station 200A (for example, the number of communication) (for example, “103”).

Here, the transmission power held as the use history may be an average value of transmission power during communication (for example, an average value of time every 3 seconds). Further, the transmission power held as the usage history may be, for example, a simple total value of power input to each antenna described later included in the second transmission antenna 224.

Even if the line status of the wireless backhaul line 20 changes from moment to moment by using the average value of the transmission power as information on the history of use of the transmission power, the history database T22 uses a value in which the influence of the change is smoothed. Can hold.

Since one macro cell base station 200A to which the small cell base station 200B is connected is determined for the small cell base station 200B, the identification information of the macro cell base station 200A is not held in the history databases T21 and T22. It's okay.

The second interface 221 is a communication interface for connecting the small cell base station 200B and the subordinate terminal 100. The second interface 221 is an interface for communicating via a RAN (Radio Access Network).

The second packet generator 222 generates a packet (second transmission packet) transmitted to the macrocell base station 200A. The second transmission packet includes data on the uplink 21. The data (control data and user data) of the uplink 21 is obtained from, for example, the memory 260B, an external device (not shown) such as a storage device, and various software processing units (not shown).

The second packet generation unit 222 sends information on the usage history of the radio resources for the uplink 21 related to the communication of the second transmission packet to the second radio resource management unit 228. The information on the usage history of the radio resource includes, for example, information on the radio frequency used for communication with the macro cell base station 200A and information on the communication amount communicated using the radio frequency.

The second wireless transmission unit 223 refers to the history database T22, and based on the past transmission power usage history used for communication with the macro cell base station 200A, the initial transmission power used for communication with the macro cell base station 200A A value is derived and an initial value of the transmission power is set.

For example, the second wireless transmission unit 223 determines the transmission power with a large usage history (high usage history) as the initial value of the transmission power used for the uplink 21 communication. The transmission power having a high usage history may be, for example, the transmission power having the highest frequency accumulated in the history database T22, or may be the transmission power having the frequency equal to or higher than the predetermined frequency even if it is not the highest.

The second wireless transmission unit 223 updates the transmission power usage history information held in the history database T22 based on the transmission power used for communication of the second transmission packet. This transmission power usage history information includes, for example, information on transmission power used for uplink 21 communication with the macrocell base station 200A and information on frequency of communication using this transmission power.

For example, the second wireless transmission unit 223 adds, for example, “1” to the frequency to the transmission power of the history database T22 that matches the transmission power (current transmission power) related to the transmission of the second transmission packet, Information held in the database T22 is updated.

The second wireless transmission unit 223 transmits the second transmission packet to the macro cell base station 200A via the uplink 21 and the second transmission antenna 224. At this time, the second radio transmission unit 223 uses the radio resource allocated by the second radio resource management unit 228 to transmit with the transmission power set by the second radio transmission unit 223.

The second radio transmission unit 223 includes, in a control signal, information on radio resources allocated to communication on the uplink 21 (radio resource allocation information) and transmits the information to the macro cell base station 200A. The radio resource allocation information for the uplink 21 is used at the time of reception in the macro cell base station 200A.

The second radio reception unit 226 receives a packet (first reception packet) from the macrocell base station 200A using the radio resources for the downlink 22 allocated by the second radio resource management unit 228.

The second packet decoding unit 227 decodes the first received packet to obtain first decoded data. The first decoded data includes downlink data 22. Data on the downlink 22 (control data and user data) is transferred to, for example, the memory 260B, an external device (not shown) such as a storage device or a display device, and processing units (not shown) of various software.

Further, the data of the uplink 21 includes radio resource allocation information for the uplink 21. Second packet decoding section 227 transmits radio resource allocation information for uplink 21 to second radio resource management section 228.

The second packet decoding unit 227 sends information on the usage history of the radio resource related to the communication of the first received packet to the second radio resource management unit 228.

The second radio resource management unit 228 refers to the history database T21, and based on the radio frequency usage history used for communication with the past macro cell base station 200A, the uplink 21 used for communication with the macro cell base station 200A. A radio frequency allocation candidate for the system is derived.

For example, the second radio resource management unit 228 determines a radio frequency having a high usage history (high usage history) as a radio frequency allocation candidate to be allocated to communication on the uplink 21. The radio frequency with a large usage history may be, for example, the radio frequency with the largest amount of communication stored in the history database T21, or the radio frequency with the communication data amount equal to or greater than a predetermined amount. Note that a plurality of radio frequency candidates from a candidate with a high priority to a candidate with a low priority may be included.

The second radio resource management unit 228 searches for the allocation status of RBs in radio frequency allocation candidates and determines whether there is an unallocated RB in this radio frequency. The second radio resource management unit 228 determines that this radio frequency can be allocated when there is an unallocated RB. The second radio resource management unit 228 allocates radio resources (radio frequencies and unallocated RBs) that can be allocated as radio resources used for uplink communication with the macro cell base station 200A.

The second radio resource management unit 228 acquires the radio resource allocation information for the downlink 22 from the second packet decoding unit 227, and stores the radio resource allocation information for the downlink 22 in, for example, the memory 260B for management. . The first radio resource management unit 208 allocates radio resources for the downlink 22 based on the radio resource allocation information for the downlink 22.

Also, the second radio resource management unit 228 may specify AMC together with RB allocation.

The second radio resource management unit 228 may change the radio frequency and select a new radio frequency from other allocation candidate radio frequencies when the allocation candidate radio frequencies cannot be allocated.

Also, the second radio resource management unit 228 acquires information on the use history of the radio resource from the second packet generation unit 222. For example, the second radio resource management unit 228 adds the communication amount included in the usage history information to the radio frequency of the history database T21 that matches the radio frequency included in the acquired usage history information, Information held in the database T21 is updated.

The second radio resource management unit 228 uses the second radio transmission unit 223 to transmit information on the allocated radio resource for the uplink 21, that is, information on the radio frequency and RB used for communication on the uplink 21 with the macro cell base station 200A. Send to.

The second radio resource management unit 228 uses the second radio reception unit 226 to transmit the information on the allocated radio resources for the downlink 22, that is, the radio frequency and RB information used for the downlink 22 communication with the macrocell base station 200A. Send to.

[Operation etc.]
Next, an operation example of the wireless communication system 10 will be described.

FIG. 7 is a flowchart showing a first operation example when the base station 200 assigns a radio frequency used in the wireless backhaul line 20. FIG. 7 shows an operation example when the macro cell base station 200A allocates a radio frequency to be used in the downlink 22.

First, the first radio resource management unit 208 determines whether various settings need to be made on the wireless backhaul line 20 (S11). The various settings include, for example, setting of radio resources used in communication of the wireless backhaul line 20 (downlink 22), and an initial value of transmission power when communicating via the wireless backhaul line 20 by the first transmission antenna 204. Including settings. For example, when the terminal 100 exists under the macro cell base station 200A or the small cell base station 200B, the first radio resource management unit 208 determines that the various settings are necessary.

When the various settings described above are necessary, the first radio resource management unit 208 refers to the history database T11 (S12), and has a high usage frequency (such as a history of usage history) such as the largest traffic in the small cell base station 200B. A radio frequency is selected as a radio frequency allocation candidate (S13).

The first radio resource management unit 208 determines whether or not RBs in radio frequency allocation candidates can be allocated, for example, by the method described above (S14).

In S14, when the RB of the selected radio frequency cannot be allocated, the first radio resource management unit 208 determines whether or not the priority order of the radio frequency set as the allocation candidate is the lowest (S15). ).

For example, when the process of S15 is the first time, the priority order of the allocation candidate radio frequency is the highest, for example, and the priority order of the allocation candidate radio frequency is lowered each time the number of processes of S15 increases.

In S15, when the priority order of the radio frequency set as the allocation candidate is not the lowest, the first radio resource management unit 208 determines that the radio frequency having a one-step priority lower than this radio frequency, that is, the radio frequency of the next priority order. Is selected as an allocation candidate (S16). Then, the macro cell base station 200A proceeds to the process of S14.

In S15, the first radio resource management unit 208 indicates the history information indicating that the wireless backhaul line 20 cannot be set when the priority order of the radio frequency set as the allocation candidate is the lowest in S15. (S17). The unusable history information includes, for example, information of the small cell base station 200B that cannot be allocated, the radio frequency that cannot be allocated, and the time (for example, date and time) that cannot be allocated. And macrocell base station 200A complete | finishes the process of FIG.

In S14, when it is possible to allocate radio frequency RBs, the first radio resource management unit 208 allocates radio frequency RBs that can be allocated. Then, the first radio resource management unit 208 sets transmission power (S18). This transmission power corresponds to the power supplied to the first transmission antenna 204. The transmission power setting may be performed using the history database T21 as in S32 to S35 shown in FIG. 9, for example, or may be performed by a known method.

The first radio transmission unit 203 communicates data with the small cell base station 200B with the set transmission power using the RB of the allocated radio frequency (S19). The allocated radio frequency information is included in the radio resource allocation information for the downlink 22, and is notified to the small cell base station 200B.

When the data is communicated, the first packet generation unit 202 sends information on the traffic amount of the transmitted first transmission packet to the first radio resource management unit 208. The first radio resource management unit 208 updates the communication history (communication amount) at the radio frequency used in the communicated small cell base station 200B in the history database T11 (S20). And macrocell base station 200A complete | finishes the process of FIG.

In this way, the macro cell base station 200A can assign a radio frequency with a low possibility of communication interference using information on past use history of radio frequency related to data communication. In addition, when it is impossible to allocate RBs of candidate radio frequencies, allocation of RBs of other radio frequencies increases the possibility that the macro cell base station 200A can find a radio frequency for communicating data. That is, the macro cell base station 200A can improve the allocation efficiency and the utilization efficiency of radio resources. Therefore, the macro cell base station 200A can autonomously distribute radio frequencies used for communication with the small cell base station 200B via the wireless backhaul line 20.

FIG. 8 is a flowchart showing a second operation example when the base station 200 assigns a radio frequency to be used in the wireless backhaul line 20. FIG. 8 illustrates an operation example when the small cell base station 200B allocates a radio frequency to be used in the uplink 21. In FIG. 8, the same processes as those in FIG. 7 are denoted by the same reference numerals, and the description thereof is omitted or simplified.

First, the second radio resource management unit 228 determines whether various settings on the wireless backhaul line 20 are necessary (S21). The various settings include, for example, the setting of radio resources used in the communication of the wireless backhaul line 20 (uplink 21), and the initial value of the transmission power when the second transmission antenna 224 communicates via the wireless backhaul line 20. Including settings. For example, when the terminal 100 exists under the macro cell base station 200A or the small cell base station 200B, the second radio resource management unit 228 determines that the various settings are necessary.

When the above various settings are necessary, the second radio resource management unit 228 refers to the history database T21 (S22), and selects a radio frequency with a high use frequency (a lot of use history) such as the largest amount of communication. It is selected as a radio frequency allocation candidate (S23).

The second radio resource management unit 228 determines whether or not RBs in radio frequency allocation candidates can be allocated, for example, by the method described above (S24).

In S24, when the RB of the selected radio frequency cannot be allocated, the second radio resource management unit 228 determines whether or not the priority order of the radio frequency determined as the allocation candidate is the lowest (S25). ).

For example, when the process of S25 is the first time, for example, the priority of the radio frequency of the allocation candidate is the highest, and the priority of the radio frequency of the allocation candidate is lowered every time the number of processes of S25 increases.

In S25, when the priority order of the radio frequency set as the allocation candidate is not the lowest, the second radio resource management unit 228 determines that the radio frequency having a one-step priority lower than this radio frequency, that is, the radio frequency of the next priority order. Is selected as an allocation candidate (S26). Then, the small cell base station 200B proceeds to the process of S24.

In S25, the second radio resource management unit 228 indicates the impossible history information indicating that the setting of the wireless backhaul line 20 is impossible when the priority of the radio frequency set as the allocation candidate is the lowest in S25. (S27). The impossibility history information includes, for example, information on radio frequencies that could not be assigned and times (eg, date and time) when assignment was not possible. And the small cell base station 200B complete | finishes the process of FIG.

In S24, when the RB of the radio frequency can be allocated, the second radio resource management unit 228 allocates the RB of the radio frequency that can be allocated. Then, the second radio resource management unit 228 sets transmission power (S28). This transmission power corresponds to the power supplied to the second transmission antenna 224. The setting of the transmission power may be performed using the history database T22 as in S42 to S45 shown in FIG. 10, for example, or may be performed by a known method.

The second radio transmission unit 223 communicates data with the macrocell base station 200A with the set transmission power using the RB of the allocated radio frequency (S29). The allocated radio frequency and RB information are included in the radio resource allocation information for the uplink 21 and notified to the macro cell base station 200A.

When the data is communicated, the second packet generation unit 222 sends information on the amount of communication of the transmitted second transmission packet to the second radio resource management unit 228. The second radio resource management unit 228 updates the communication history (communication amount) at the used radio frequency in the history database T21 (S30). And the small cell base station 200B complete | finishes the process of FIG.

In this way, the small cell base station 200B can assign a radio frequency with a low possibility of communication interference using information on past radio frequency usage history related to data communication. In addition, when it is impossible to allocate RBs of candidate radio frequencies, allocation of RBs of other radio frequencies increases the possibility that the small cell base station 200B can find a radio frequency for communicating data. That is, the small cell base station 200B can improve radio resource allocation efficiency and utilization efficiency. Therefore, the small cell base station 200B can autonomously distribute radio frequencies used for communication with the macro cell base station 200A via the wireless backhaul line 20.

FIG. 9 is a flowchart illustrating a first operation example when the base station 200 sets transmission power used in communication via the wireless backhaul line 20. FIG. 9 shows an operation example when the macrocell base station 200A sets transmission power. 9, the same processes as those in FIGS. 7 and 8 are denoted by the same reference numerals, and the description thereof is omitted or simplified.

First, the first radio resource management unit 208 determines whether various settings need to be made on the wireless backhaul line 20 (S11).

If various settings are required, the first radio resource management unit 208 allocates radio resources including radio frequencies for the downlink 22 (S31). This radio resource allocation may be performed using the history database T11 as in S12 to S17 shown in FIG. 7, or may be performed by a known method.

The first wireless transmission unit 203 refers to the history database T12 (S32), and uses the first transmission antenna 204 to transmit a transmission power having a high usage frequency (a lot of usage history) such as the highest frequency. The initial value of power is set (S33). This frequency is the frequency of transmission power used in the radio frequency used in communication with the small cell base station 200B.

Note that the first wireless transmission unit 203 may set transmission power that is 3 dB larger or 3 dB smaller than the most frequent transmission power as the initial value of the transmission power in the history database T12. .

The first wireless transmission unit 203 transmits data of the downlink 22 to the small cell base station 200B based on the set initial value of transmission power via the first transmission antenna 204 (S34).

In S34, the first wireless transmission unit 203 supplies the initial value of the transmission power to the first transmission antenna 204 before data communication. Further, the first wireless transmission unit 203 supplies the transmission power determined by the transmission power control during the data communication to the first transmission antenna 204 during the data communication.

In transmission power control during data communication, for example, if the reception power at the reception point (here, the second reception antenna 225) is equal to or greater than a predetermined value, the first wireless transmission unit 203 uses the transmission power from the first transmission antenna 204. A specified value (for example, 1 dB) is reduced. On the other hand, if the reception power at the reception point (second reception antenna 225 in this case) is equal to or less than a predetermined value, the transmission power by the first transmission antenna 204 is increased by a specified value (for example, 1 dB). The received power information is notified from the receiving side (here, the small cell base station 200B) to the transmitting side (here, the macro cell base station 200A) via, for example, the reverse line (here, the uplink 21).

When the data is communicated in S34, the first radio transmission unit 203 accesses the history database T12, and based on the information on the transmission power used, the first radio transmission unit 203 uses the radio frequency used for communication with the small cell base station 200B. The frequency of the transmission power is updated (S35). And macrocell base station 200A complete | finishes the process of FIG.

As described above, the macro cell base station 200A uses the transmission power usage history information at the past radio frequency used for data communication, thereby reducing the transmission quality and the possibility of communication interference. Can be set. That is, the macrocell base station 200A can prevent the transmitted data from reaching the small cell base station 200B and reducing the quality of data communication by setting the initial value of the transmission power to be too small. Further, the macrocell base station 200A can suppress the occurrence of communication interference in the base stations 200 and the like around the small cell base station 200B by setting the initial value of the transmission power to be excessive. Accordingly, the macro cell base station 200A can autonomously distribute transmission power used for communication with the small cell base station 200B via the wireless backhaul line 20.

FIG. 10 is a flowchart showing a second operation example when the base station 200 sets transmission power used for communication via the wireless backhaul line 20. FIG. 10 shows an operation example when the small cell base station 200B determines transmission power. In FIG. 10, the same processes as those in FIGS. 7 to 9 are denoted by the same reference numerals, and the description thereof is omitted or simplified.

First, the second radio resource management unit 228 determines whether various settings on the wireless backhaul line 20 are necessary (S21).

If various settings are required, the second radio resource management unit 228 allocates radio resources including radio frequencies for the uplink 21 (S41). This radio resource allocation may be performed using the history database T21 as in S22 to S27 shown in FIG. 8, or may be performed by a known method.

The second wireless transmission unit 223 refers to the history database T22 (S42), and uses the second transmission antenna 224 to transmit the transmission power having a high usage frequency (a lot of usage history) such as the highest frequency. The initial value of power is set (S43). This frequency is the frequency of transmission power used in the radio frequency used in communication with the macrocell base station 200A.

The second wireless transmission unit 223 transmits the data of the uplink 21 to the macrocell base station 200A via the second transmission antenna 224 based on the set initial value of transmission power (S44).

In S44, the second wireless transmission unit 223 supplies the initial value of the transmission power to the second transmission antenna 224 before data communication. Further, the second wireless transmission unit 223 supplies the transmission power determined by the transmission power control during the data communication to the second transmission antenna 224 during the data communication.

In transmission power control during data communication, for example, if the reception power at the reception point (here, the first reception antenna 205) is equal to or greater than a predetermined value, the first wireless transmission unit 203 uses the transmission power from the second transmission antenna 224. A specified value (for example, 1 dB) is reduced. On the other hand, if the reception power at the reception point (here, the first reception antenna 205) is equal to or less than a predetermined value, the transmission power by the second transmission antenna 224 is increased by a specified value (for example, 1 dB). The received power information is notified from the reception side (here, the macro cell base station 200A) to the transmission side (here, the small cell base station 200B) via, for example, a reverse line (here, the downlink 22).

When the data is communicated in S44, the second radio transmission unit 223 accesses the history database T22, and based on the information on the transmission power used, the second radio transmission unit 223 uses the radio frequency used for communication with the macrocell base station 200A. The frequency of transmission power is updated (S45). And the small cell base station 200B complete | finishes the process of FIG.

As described above, the small cell base station 200B uses the transmission power usage history information at the past radio frequency used for data communication, thereby transmitting with low communication quality and low possibility of communication interference. You can set the power. That is, the small cell base station 200 B can prevent the transmitted data from reaching the macro cell base station 200 A and the quality of data communication from being deteriorated by setting the initial value of the transmission power to be too small. Further, the small cell base station 200B can suppress the occurrence of communication interference in the base stations 200 and the like around the macro cell base station 200A by setting the initial value of the transmission power to be excessive. Therefore, the small cell base station 200 B can autonomously distribute transmission power used for communication with the macro cell base station 200 A via the wireless backhaul line 20.

[Transmission power control]
Next, transmission power control related to data communication will be described.

As shown in FIGS. 11 to 14, the first transmission antenna 204, the first reception antenna 205, the second transmission antenna 224, and the second reception antenna 225 have a MIMO (Multiple-Input and Multiple-Output) antenna. . That is, each of the first transmission antenna 204, the first reception antenna 205, the second transmission antenna 224, and the second reception antenna 225 has a plurality of antennas. The plurality of antennas may be provided physically or may be provided logically. 11 to 14 exemplify that each of the macro cell base station 200A and the small cell base station 200B has eight transmission MIMO antennas and eight reception MIMO antennas.

FIG. 11 is a schematic diagram for explaining a first control example of transmission power by the wireless communication system 10. In FIG. 11, it is assumed that each antenna # A11 to # A18 of the first transmission antenna 204 of the macrocell base station 200A transmits different data. In this case, for example, each antenna # B21 to # B28 of the second receiving antenna 225 of N small cell base stations 200B receives data from the macrocell base station 200A. The reception power when each small cell base station 200B receives is substantially uniform, for example.

In FIG. 11, one small cell base station is connected to one wireless backhaul line 20 and one radio frequency is used. Therefore, as many wireless backhaul lines 20 as the number of small cell base stations 200B connected to the macro cell base station 200A are provided.

The first wireless transmission unit 203 performs serial-to-parallel conversion (S / P: Serial-to-Parallel conversion) on the first transmission data sequence (data on the downlink 22) included in the first transmission packet. The first wireless transmission unit 203 performs baseband processing on the transmission data # A51 to # A58 subjected to serial / parallel conversion.

Also, the first radio transmission unit 203 refers to the history database T12 and sets an initial value of transmission power based on the radio frequency assigned by the first radio resource management unit 208. The first wireless transmission unit 203 sets, for example, transmission power whose frequency is equal to or higher than a predetermined frequency (for example, the maximum) in the assigned wireless frequency as an initial value of the transmission power.

The first radio transmission unit 203 may set an initial value of transmission power based on a RAT that can be adopted by the small cell base station 200B.

When the RAT is determined, the first wireless transmission unit 203 determines the number of antennas used for MIMO communication and the presence / absence of directivity formation. Here, it is assumed that there is no directivity formation. First radio transmission section 203 determines the ratio of the power supplied to each antenna # A11 to # A18 based on the determined RAT (transmission power setting). Here, since the directivity is not formed, the value of the power supplied to each antenna # A11 to # A18 is the same.

The first wireless transmission unit 203 controls the supply power so that the total value of the power supplied to the antennas # A11 to # A18 becomes the initial value of the set transmission power. Therefore, here, the value obtained by dividing the transmission power by the number of MIMO antennas (eight) is the power supplied to each antenna. In this way, the initial transmission power for data communication is set.

The first radio transmission unit 203 transmits the transmission data # A51 to the small cell base station 200B via the MIMO antennas # A11 to # A18 with the set transmission power using the radio resources allocated. Start transmission of # A58.

Also, as described above, the first wireless transmission unit 203 supplies the transmission power determined by the transmission power control during data communication to each antenna # A11 to # A18 of the first transmission antenna 204.

Therefore, the transmission power by the first transmission antenna 204 may be adjusted from the initial value, but the transmission power adjustment amount can be reduced by setting the initial value using past history information of the transmission power. .

The second radio reception unit 226 receives signals from the macrocell base station 200A via the antennas # B21 to # B28 of the second reception antenna 225. Second radio reception section 226 separates the received signals according to a known signal separation algorithm to obtain received data # B61 to # B68. The received signal includes data on the downlink 22.

The second wireless reception unit 226 performs parallel-to-serial conversion (P / S: Parallel-to-Serial-conversion) on the received data # B61 to # B68. Reproduced data is obtained by parallel-serial conversion. When the data is normally restored by the second radio reception unit 226, the reproduction data corresponds to the first transmission data sequence.

The first wireless transmission unit 203 also sums (adds) the power supplied to the antennas # A11 to # A18, for example, and stores the average value of the total value for every predetermined time (for example, 3 seconds) in the history database T12. reflect. For example, in the history database T12, the first radio transmission unit 203 sets the frequency to “1” for the transmission power in which the RAT and the radio frequency related to the current data communication match and the calculated average value per predetermined time matches. Add and update. Accordingly, as the communication time becomes longer with the same transmission power, a larger value is added to the frequency of the corresponding transmission power.

According to the first control example of transmission power, since different data are communicated in parallel, the transmission speed is increased. In the first control example, since a directivity pattern is not formed, transmission data is transmitted with equal power around the macro cell base station 200A. Therefore, the macro cell base station 200A can increase the transmission speed of the wireless backhaul line 20 by using MIMO.

FIG. 12 is a schematic diagram for explaining a second example of transmission power control by the wireless communication system 10. In FIG. 12, it is assumed that each antenna # A11 to # A18 of the first transmission antenna 204 of the macrocell base station 200A transmits the same data. In this case, the antennas # B21 to # 28 of the second receiving antennas 225 of the N small cell base stations 200B receive data from the macro cell base station 200A. The received power when each small cell base station 200B receives is different depending on the directivity, for example.

In FIG. 12, N small cell base stations are connected to one wireless backhaul line 20 and one radio frequency is used.

In FIG. 12, the description of the same items as those described in FIG. 11 is omitted or simplified.

The first radio transmission unit 203 refers to the history database T12, and based on the RAT for communicating with the small cell base station 200B and the radio frequency assigned by the first radio resource management unit 208, the transmission power Set the initial value. This RAT is determined for each small cell base station 200B from among RATs that can be adopted by the small cell base station 200B. For example, in the RAT for communicating with the small cell base station 200B, the first radio transmission unit 203 uses, as an initial value of transmission power, transmission power whose frequency is a predetermined frequency or more (for example, the maximum) in the assigned radio frequency. Set.

When the RAT is determined, the first wireless transmission unit 203 determines the number of antennas used for MIMO communication and the presence / absence of directivity formation. Here, it is assumed that the formation of directivity is determined. First radio transmission section 203 determines the ratio (transmission weight (weight)) of power supplied to each antenna # A11 to # A18 based on the determined RAT (transmission weight generation). The determined ratio of supplied power is indicated by WI _{, J.} Here, “I” indicates the identifier of the communication target small cell base station 200 B, and “J” indicates the identifier of the MIMO antenna in the first transmission antenna 204.

Based on the ratio of the power supplied to each antenna # A11 to # A18, first wireless transmission section 203 determines that the total value of the power supplied to each antenna # A11 to # A18 is the initial value of the set transmission power. The supplied power is controlled so that Thereby, the transmission power of the initial data communication is determined.

First radio transmission section 203 transmits transmission data included in a first transmission data sequence (data on downlink 22) addressed to each small cell base station 200B (SBS # 1 to SBS # N) to each antenna # A11 to Send to # A18. Here, the first transmission data sequence includes a data sequence transmitted to each small cell base station 200B (SBS # 1 to SBS # N). At this time, the first wireless transmission unit 203 performs baseband processing on each transmission data, multiplies the supplied power ratios W _{I and J} , and transmits each small cell to the same antennas # A11 to # A18. The transmission data addressed to the base station 200B is added.

The first radio transmission section 203 transmits transmission data to each small cell base station 200B using the allocated radio resources with the determined transmission power via the MIMO antennas # A11 to # A18. To start.

The second radio reception unit 226 of each small cell base station 200B receives a signal from the macro cell base station 200A via each antenna # B21 to # B28 of the second reception antenna 225. The second wireless reception unit 226 separates the received signal according to a known signal separation algorithm to obtain reproduction data. When the data is normally restored by the second radio reception unit 226, the reproduction data corresponds to the first transmission data sequence.

According to the second control example of transmission power, since the same data is communicated in parallel, the macrocell base station 200A can transmit with directivity formed by beamforming. The greater the number of MIMO antennas in the first transmission antenna 204, the sharper the directivity pattern, and the macrocell base station 200A can increase the transmission distance for transmission. Therefore, the macro cell base station 200A can improve the SNR (Signal to Noise Ratio) of the wireless backhaul line 20 by utilizing MIMO.

Note that the number of MIMO antennas in the first transmission antenna 204 is preferably considerably larger than the number of spatial multiplexing. Thereby, the directivity separation performance in the wireless communication system 10 can be improved. This spatial multiplexing number corresponds to the number of small cell base stations 200B connected to the macro cell base station 200A.

FIG. 13 is a schematic diagram for explaining a third control example of transmission power by the wireless communication system 10. In FIG. 13, it is assumed that each antenna # B11 to # B18 of the second transmission antenna 224 of the small cell base station 200B transmits different data. In this case, each antenna # A21 to # A28 of the first receiving antenna 205 of the macrocell base station 200A receives data from the small cell base station 200B.

The second wireless transmission unit 223 performs serial-parallel conversion on the second transmission data sequence (uplink 21 data) included in the second transmission packet. Second radio transmission section 223 performs baseband processing on transmission data # B51 to # B58 subjected to serial / parallel conversion.

Also, the second wireless transmission unit 223 refers to the history database T21 and sets an initial value of transmission power based on the radio frequency assigned by the second radio resource management unit 228. For example, the second wireless transmission unit 223 sets transmission power having a frequency equal to or higher than a predetermined frequency (for example, the maximum) in the assigned wireless frequency as an initial value of the transmission power.

Note that the second radio transmission unit 223 may set an initial value of transmission power based on a RAT that can be adopted by the macrocell base station 200A.

When the RAT is determined, the second wireless transmission unit 223 determines the number of antennas used for MIMO communication and the presence / absence of directivity formation. Here, it is assumed that there is no directivity formation. Second radio transmission section 223 determines the ratio of power supplied to antennas # B11 to # B18 based on the determined RAT (transmission power setting). Here, since no directivity is formed, the value of the power supplied to each antenna # B11 to # B18 is the same.

The second wireless transmission unit 223 controls the supply power so that the total value of the power supplied to the antennas # B11 to # B18 becomes the initial value of the set transmission power. Therefore, here, the value obtained by dividing the transmission power by the number of MIMO antennas (eight) is the power supplied to each antenna. In this way, the initial transmission power for data communication is set.

The second radio transmission section 223 transmits the transmission data # B51 to #B via the MIMO antennas # B11 to # B18 with the determined transmission power using the radio resources allocated to the macro cell base station 200A. The transmission of B58 is started.

Also, as described above, the second wireless transmission unit 223 supplies the transmission power determined by the transmission power control during data communication to the antennas # B11 to # B18 of the second transmission antenna 224.

Accordingly, the transmission power by the second transmission antenna 224 may be adjusted from the initial value, but the transmission power adjustment amount can be reduced by setting the initial value using past history information of the transmission power. .

The first radio reception unit 206 receives a signal from the small cell base station 200B via each antenna # A21 to # A28 of the first reception antenna 205. First radio reception section 206 separates the received signals according to a known signal separation algorithm to obtain received data # A61 to # A68. The received signal includes data on the uplink 21.

The first wireless reception unit 206 performs parallel-serial conversion on the received data # A61 to # A68. Reproduced data is obtained by parallel-serial conversion. When the data is normally restored by the first wireless reception unit 206, the reproduction data corresponds to the second transmission data series.

In addition, the second wireless transmission unit 223, for example, sums (adds) the power supplied to the antennas # B11 to # B18, and stores an average value of the total value every predetermined time (for example, 3 seconds) in the history database T22. reflect. For example, in the history database T22, the second wireless transmission unit 223 sets the frequency to “1” for the transmission power in which the RAT and the wireless frequency related to the current data communication match and the calculated average value per predetermined time matches. Add and update. Accordingly, as the communication time becomes longer with the same transmission power, a larger value is added to the frequency of the corresponding transmission power.

According to the third control example of transmission power, since different data are communicated in parallel, the transmission speed is increased. In the third control example, since a directivity pattern is not formed, transmission data is transmitted around the small cell base station 200B with equal power. Therefore, the small cell base station 200B can increase the transmission speed of the wireless backhaul line 20 by using MIMO.

FIG. 14 is a schematic diagram for explaining a fourth control example of transmission power by the wireless communication system 10. In FIG. 14, it is assumed that each antenna # B11 to # B18 of the second transmission antenna 224 of the small cell base station 200B transmits the same data. In this case, each antenna # A21 to # A28 of the first receiving antenna 205 of the macrocell base station 200A receives data from the small cell base station 200B.

In FIG. 14, the description of the same items as those described in FIG. 12 is omitted or simplified.

The second radio transmission unit 223 refers to the history database T22, and based on the RAT for communicating with the macrocell base station 200A and the radio frequency allocated by the second radio resource management unit 228, the initial transmission power Set the value. This RAT is determined from RATs that can be adopted by the macrocell base station 200A. For example, in the RAT for communicating with the macrocell base station 200A, the second radio transmission unit 223 sets, as an initial value of the transmission power, a transmission power whose frequency is equal to or higher than a predetermined frequency (for example, the maximum) in the assigned radio frequency. To do.

When the RAT is determined, the second wireless transmission unit 223 determines the number of antennas used for MIMO communication and the presence / absence of directivity formation. Here, it is assumed that the formation of directivity is determined. Also, the second radio transmission unit 223 determines the ratio (transmission weight) of the power supplied to each antenna # B11 to # B18 based on the determined RAT (transmission weight generation).

Based on the ratio of the power supplied to each antenna # B11 to # B18, the second wireless transmission unit 223 determines the total value of the power supplied to each antenna # B11 to # B18 as the initial value of the set transmission power. The supplied power is controlled so that Thereby, the transmission power of the initial data communication is determined.

The second wireless transmission unit 223 transmits the transmission data included in the second transmission data series (uplink 21 data) to each of the antennas # B11 to # B18. At this time, the second wireless transmission unit 223 performs baseband processing on each transmission data and multiplies the ratio of the supplied power.

Second radio transmission section 223 starts transmission of transmission data to macro cell base station 200A via MIMO antennas # B11 to # B18 with the determined transmission power using the allocated radio resources. To do.

The first radio reception unit 206 of the macro cell base station 200A receives signals from the small cell base station 200B via the antennas # A21 to # A28 of the first reception antenna 205. The first wireless reception unit 206 separates the received signal according to a known signal separation algorithm to obtain reproduction data. When the data is normally restored by the first wireless reception unit 206, the reproduction data corresponds to the second transmission data series.

According to the fourth control example of transmission power, since the same data is communicated in parallel, the small cell base station 200B can transmit with directivity formed by beam forming. As the number of MIMO antennas in the second transmission antenna 224 increases, this directivity pattern becomes sharper, and the small cell base station 200B can transmit with an increased transmission distance. Therefore, the small cell base station 200B can improve the SNR of the wireless backhaul line 20 by utilizing MIMO.

[Effects]
As described above, the base station 200 holds the history database T11 or T21 that holds information on the use history of radio frequencies related to communication with other base stations 200. When the base station 200 needs to set the wireless backhaul line 20, the base station 200 refers to the history database T11 or T21, determines the priority of radio frequency allocation, and performs radio resources (radio frequency, radio frequency) related to data communication. Part of the frequency).

Thus, even when the backhaul line is wireless instead of a wired line such as an optical line, wireless resources to be used for communication can be determined dynamically. Therefore, the radio communication system 10 does not need to add an optical line every time the base station 200 (for example, the small cell base station 200B) is added, can reduce the cost required for installing the base station, and can quickly install the base station. Can be improved.

In addition, it is not necessary to assign a radio frequency to each wireless backhaul line 20 in the radio communication system 10 in advance, and it is possible to suppress a specific radio frequency from being used too much or too little. Therefore, the base station 200 can improve the utilization efficiency of radio resources. In addition, since radio frequencies are not fixedly assigned in advance, it is possible to reduce the shortage of usable radio frequencies.

In addition, the base station 200 can omit a huge amount of line quality information detection processing for determining a communication environment using a radio frequency. This line quality information includes, for example, SINR (Signal to Interference Noise Ratio).

A radio frequency with a large past communication history (for example, with a large amount of communication) represents that the base station 200 adopting the radio frequency is a radio frequency with relatively little communication interference with surrounding base stations. Therefore, it is preferable that such a radio frequency is allocated to communication with another base station 200 via the wireless backhaul line 20.

In addition, in the radio frequency that has been frequently used in the past, the amount of data to be accumulated increases, so that there is a high possibility that this radio frequency is selected as a candidate. A radio frequency that has been frequently used in the past is likely to be successfully communicated between the base stations 200 in the future. Therefore, the base station 200 can improve the communication accuracy in communication with other base stations 200 via the wireless backhaul line 20, and can reduce the need for reassignment of radio resources. Therefore, the base station 200 can improve radio resource allocation efficiency.

In addition, the base station 200 suppresses the occurrence of interference between communications using the same radio frequency by considering past communication histories without using beamforming technology or M-MIMO (Massive MIMO) technology. it can. In addition, even when the number of installed base stations 200 in the radio communication system 10 increases and communication interference increases in the beam forming technique or the M-MIMO technique, the base station 200 can perform communication by considering past communication history. Increase in interference can be reduced.

In addition, the base station 200 is aware of which radio frequency is assigned to the other base station 200 by deriving radio frequency assignment candidates according to the past use history using each radio frequency. There is no need. Therefore, the base station 200 does not need to be aware of which communication carrier owns the other base station 200. Therefore, even when a plurality of base stations of the same communication carrier communicate via the wireless backhaul line 20, the base station 200 communicates via a wireless backhaul line 20 with a plurality of base stations of different communication carriers. Even in this case, a radio frequency with less interference can be easily and accurately assigned to the base station 200 of the communication partner.

In addition, when TDD (Time Division Duplex) is adopted for the wireless backhaul line 20, synchronization between a plurality of base stations 200 and radio resource allocation patterns on the uplink 21 and the downlink 22 are not unified. Prone to communication interference. In TDD, time division is performed on the uplink 21 and the downlink 22 at the same carrier frequency. In particular, communication interference occurs regularly between the base stations 200 installed at fixed positions as compared with communication between the base station 200 and a mobile terminal (for example, the terminal 100), and thus it is more difficult to avoid communication interference. . On the other hand, according to the radio | wireless communications system 10, generation | occurrence | production of communication interference can be suppressed by assigning a radio frequency according to the past performance.

Therefore, even if the backhaul line is a heterogeneous network and a radio line, the base station 200 reduces the occurrence of communication interference (inter-cell interference) between the plurality of base stations 200, and uses radio resources for data retransmission. Frequent allocation processing can be suppressed.

Also, the base station 200 holds a history database T12 or T22 that holds information on the use history of transmission power for each radio frequency related to communication with another base station 200. When the wireless backhaul line 20 needs to be set, the base station 200 refers to the history database T12 or T22 and sets a provisional value (initial value) of transmission power related to data communication.

This enables the transmission power to be used for communication to be determined dynamically even when the backhaul line is wireless rather than wired such as an optical line. Therefore, even if the base station 200 (for example, the small cell base station 200B) is added, the wireless communication system 10 can suppress the occurrence of communication interference between adjacent base stations 200.

In addition, the base station 200 does not need to allocate more transmission power than necessary for communication via the wireless backhaul line 20 and can suppress excessive transmission power being used and communication interference. In addition, the base station 200 can suppress the communication quality from being deteriorated by allocating an excessive transmission power to the communication via the wireless backhaul line 20 in consideration of the communication interference.

Transmission power with a large past communication history (for example, high frequency) indicates that communication interference with surrounding base stations is relatively small and a communication success rate is high. Therefore, it is preferable that such transmission power is allocated to communication with another base station 200 via the wireless backhaul line 20.

Also, transmission power that has been frequently used in the past is more likely to be used because it is used more frequently. The transmission power frequently used in the past is less likely to be excessive or insufficient in the communication between the base stations 200 in the future, and the possibility of successful communication is high. Therefore, even if the backhaul line is a heterogeneous network and a wireless line, the base station 200 can reduce the occurrence of communication interference between a plurality of base stations 200 and improve communication accuracy.

Further, the base station 200 does not need to be aware of how much transmission power is set in other base stations 200 by setting the transmission power according to the past use history using each transmission power. . Therefore, the base station 200 does not need to be aware of which communication carrier owns the other base station 200. Therefore, even when a plurality of base stations of the same communication carrier communicate via the wireless backhaul line 20, the base station 200 communicates via a wireless backhaul line 20 with a plurality of base stations of different communication carriers. Even in this case, it is possible to easily and highly accurately perform data communication with less interference to the communication partner base station 200.

Further, as in the case of radio frequency allocation, even when TDD is adopted for the wireless backhaul line 20, the radio communication system 10 generates communication interference by setting transmission power according to past results. Can be suppressed.

In this way, the base station 200 can accurately determine which radio frequency is allocated and how much the transmission power should be. Further, the base station 200 can improve the allocation efficiency and utilization efficiency of radio resources for communicating data via the wireless backhaul line 20. Further, the base station 200 can suppress an increase in communication interference on the wireless backhaul line 20 even if the number of installed base stations 200 increases.

(Other embodiments)
As described above, the first embodiment has been described as an example of the technique in the present disclosure. However, the technology in the present disclosure is not limited to this, and can also be applied to embodiments in which changes, replacements, additions, omissions, and the like are performed.

In the first embodiment, the base station 200 may acquire information on the amount of communication related to history and information on resetting the history via an interface (not shown). The interface includes, for example, a UI (User Interface) that receives information related to a usage history from a user, or a communication interface that receives information related to a usage history set in an external device. In this case, the first radio resource management unit 208 and the second radio resource management unit 228, for example, increase or decrease the communication amount of a specific radio frequency related to the usage history based on the acquired information, or The frequency of the specific transmission power may be increased or decreased.

For example, the base station 200 and other devices may calculate which radio frequency or transmission power is suitable for communication via the wireless backhaul line 20 by regular offline simulation or the like. . The base station 200 may acquire this calculation result and reflect it in the history databases T11, T12, T21, and T22.

As a result, in the history databases T11, T12, T21, and T22, even when the use history of the sub-optimal radio frequency and transmission power is increased instead of the optimum radio frequency and transmission power, more suitable radio frequency and transmission power are used. It is possible to increase the history of and to escape the sub-optimal state. That is, the usage history accumulated in the history databases T11, T12, T21, and T22 can be refreshed. As a result, the base station 200 can slightly correct the automatic use history accumulation and promote the use of a more appropriate radio frequency and transmission power. The base station 200 can redistribute radio resources and transmission power.

In the first embodiment, the small cell base station 200B may hold the history databases T11 and T12. The macro cell base station 200A may hold the history databases T21 and T22. In this case, the macro cell base station 200 A and the small cell base station 200 B may transmit and receive information on the use history of the radio frequency or transmission power using a control signal or the like.

In the first embodiment, it is exemplified that the macro cell base station 200A allocates the radio frequency of the downlink 22 and the small cell base station 200B allocates the radio frequency of the uplink 21. Note that the macro cell base station 200A and the small cell base station 200B may cooperate to determine an assigned radio frequency.

In the first embodiment, the base station 200 assumes that the number of MIMO antennas is eight, but may be seven or less or nine or more.

In the first embodiment, in the first control example of transmission power, the first wireless transmission unit 203 exemplifies transmitting different data without forming directivity. However, different data forming directivity is used. May be sent. In this case, the first wireless transmission unit 203 supplies power at different ratios to the MIMO antennas # A11 to # A18, as in the second control example of transmission power.

In the first embodiment, in the third control example of transmission power, the second wireless transmission unit 223 illustrated that different data is transmitted without forming directivity. However, different data is formed with directivity. May be sent. In this case, the second wireless transmission unit 223 supplies power to the MIMO antennas # B11 to # B18 at different ratios, as in the fourth control example of transmission power.

In the first embodiment, it has been described that the history databases T11 and T21 hold information on the use history of radio frequencies with other base stations in a fixed period in the past, but the use of radio frequencies regardless of the period. History information may be accumulated. In addition, it has been described that the history databases T12 and T22 hold the transmission power usage history information with other base stations in the past fixed period, but the transmission power usage history information is stored regardless of the period. May be.

In the first embodiment, the use value of the communication amount for each radio frequency is exemplified as the use history information of the radio frequency. However, other use history information may be used. Other usage history information includes, for example, the total communication time (total connection time) and the number of communication (number of connections) related to communication between the base stations 200 using the radio frequency. For example, the longer the total communication time is, the higher the number of communication is, the higher the priority for selecting the radio frequency.

In the first embodiment, the use value of the transmission power frequency is used as the transmission power usage history information. However, other usage history information may be used. The other usage history information includes, for example, a total communication time (total connection time) and a communication count (connection count) related to communication between the base stations 200 using the set transmission power. For example, the longer the total communication time is, and the greater the number of communication is, the higher the priority in which the transmission power is selected as the initial value.

In the first embodiment, the history databases T11 and T21 may be provided separately from various viewpoints. For example, the history databases T11 and T21 may be provided separately for each time zone in which radio resources are allocated. In addition, the history databases T11 and T21 may be separately provided by other known methods. As a result, the base station 200 can determine radio frequency allocation candidates according to the radio frequency usage history in consideration of various trends.

In the first embodiment, the history databases T12 and T22 may be provided separately from various viewpoints. For example, the history databases T21 and T22 may be provided separately for each time zone for setting the transmission power. In addition, the history databases T21 and T22 may be separately provided by other known methods. Thereby, the base station 200 can determine the initial value of the transmission power according to the transmission power usage history considering various trends.

In the first embodiment, the base station 200 manages the usage history of the communication amount for each radio frequency as a radio resource, and is used for communication with the other base station 200 via the wireless backhaul line 20. An example of determining a radio frequency candidate was illustrated. Note that the base station 200 is used for communication with other base stations 200 by managing the usage history of the communication amount for each time slot (separation on the time axis) on a certain radio frequency instead of the radio frequency. You may make it determine the candidate of a time slot which is a radio | wireless resource. The base station 200 is used for communication with other base stations 200 by managing the usage history of the communication amount for each combination of a radio frequency and a time slot (separation on the time axis) on the radio frequency. A combination candidate of a radio frequency and a time slot, which is a radio resource, may be determined.

For example, if there is one radio frequency (f1), and this radio frequency is divided into 16 time slots (TS), the base station 200 can select f1-TS1, f1-TS2,. -The usage history of the past traffic volume may be managed and updated for every 16 radio resources of TS16. Thereby, the base station 200 can segregate radio resources (here, time slots) between adjacent base stations.

Further, for example, when there are two radio frequencies (f1, f2) and each radio frequency is divided into 10 time slots, the base station 200 can perform f1-TS1, f1-TS2,. The usage history of the past traffic volume may be managed and updated for every 20 radio resources of f1-TS10, f2-TS1, f2-TS2,..., f2-TS10. Thereby, the base station 200 can segregate radio resources (in this case, a combination of radio frequency and time slot) between adjacent base stations.

In the first embodiment, the macro cell base station 200A and the small cell base station 200B connected via the wireless backhaul line 20 are exemplified. The first embodiment can be applied to all communication apparatuses that communicate via the wireless backhaul line 20 in a heterogeneous network. For example, the present disclosure can also be applied to a case where the line between the monitoring camera and the monitoring center is made wireless, and which radio resource is used and what the initial value of the transmission power is determined.

In the first embodiment, the processor 250 (250A, 250B) may be physically configured in any manner. However, if a programmable processor is used, the processing contents can be changed by changing the program, so that the degree of freedom in designing the processor 250 can be increased. Further, the processor 250 may be composed of one semiconductor chip or may be physically composed of a plurality of semiconductor chips. When configured by a plurality of semiconductor chips, each control of the first embodiment may be realized by separate semiconductor chips. In this case, it can be considered that one processor 250 is constituted by the plurality of semiconductor chips. The processor 250 may be configured by a member (capacitor or the like) having a function different from that of the semiconductor chip. Further, one semiconductor chip may be configured so as to realize the functions of the processor 250 and other functions.

In the first embodiment, the configuration of the base station 200 is shown in FIGS. 2 and 11 to 14, but each configuration may be realized by hardware or software.

(Outline of Embodiment of the Present Disclosure)
As described above, the base station 200 of the above embodiment communicates with other base stations 200 via the wireless backhaul line 20 in which a plurality of wireless communication schemes are mixedly used. The base station 200 includes a processor 250 and an antenna. The processor 250 allocates a radio frequency related to data communication with another base station 200 based on information on a radio frequency usage history related to data communication with another base station 200. The antenna performs data communication with another base station 200 using the assigned radio frequency.

The base station 200 is an example of a wireless communication device. The antenna is, for example, the first transmission antenna 204, the second transmission antenna 224, the first reception antenna 205, or the second reception antenna 225.

Thereby, the base station 200 can reduce the occurrence of communication interference with the surrounding base stations 200. For example, the base station 200 can suppress communication interference even if a large number of base stations 200 (for example, small cell base stations 200B) are added. Further, by making the backhaul line wireless, the cost for adding the base station 200 can be reduced, the economy can be improved, and the speed of installation of the base station can be improved. Further, since the base station 200 can reduce the number of repetitions of the radio resource allocation operation, the time required for the radio resource allocation of the base station 200 can be shortened. That is, the base station 200 can improve radio resource allocation efficiency. Further, the base station 200 can improve the utilization efficiency of radio resources without dividing the frequency among the plurality of base stations 200 in advance.

Note that the base station 200 can be configured by only the base stations of the same communication carrier, or can be configured by sharing the same radio resources among a plurality of base stations of different communication carriers. In either configuration, the base station 200 can allocate radio resources for communication via the wireless backhaul line 20 without a plurality of base stations 200 sharing information with each other.

In addition, the base station 200 may include a memory 260 that stores information on radio frequency usage history related to data communication with other base stations 200. The processor 250 may update the use history information stored in the memory 260 based on the radio frequency used for data communication by the antenna and the use history of the radio frequency.

Thus, every time the base station 200 performs data communication via the wireless backhaul line 20, the latest radio resource usage history can be reflected. Thereby, the base station 200 can improve the allocation efficiency and utilization efficiency of a radio | wireless resource.

Further, the processor 250 may assign a radio frequency related to data communication with another base station 200 by giving priority to a radio frequency with a large usage history.

Thereby, since the base station 200 can allocate radio resources that are highly likely to succeed in data communication, the data communication accuracy can be improved.

Note that the information on the use history of the radio frequency may include the amount of data communication using the radio frequency, the data communication time using the radio frequency, or the number of times of data communication using the radio frequency.

Further, the processor 250 may derive a radio frequency allocation candidate related to data communication with another base station 200 based on a use history of radio frequency related to data communication with another base station 200. . If the allocation candidate radio frequency cannot be allocated, the processor 250 may allocate another radio frequency. The antenna may perform data communication with another base station 200 using another radio frequency.

Thereby, the base station 200 can re-specify another radio frequency even when there is no available allocation candidate radio frequency, and the probability of successful data communication with the base station 200 can be improved.

Further, the base station 200 may include an interface for acquiring change information for changing the radio frequency usage history. The processor 250 may change the usage history of the radio frequency based on the change information.

As a result, the radio frequency usage history (usage record) is large, but even when the radio frequency is not optimal as a whole (suboptimal case), the base station 200 intentionally refreshes the usage history so that it is suboptimal. The convergence to the state can be avoided.

In addition, the frequency allocation method of the above embodiment is a frequency allocation method in the base station 200 that communicates with another base station 200 via the wireless backhaul line 20 in which a plurality of radio communication schemes are mixedly used. It is. This frequency allocation method allocates a radio frequency related to data communication with another base station 200 based on information on a use history of a radio frequency related to data communication with another base station 200, and assigns the assigned radio frequency. Data communication with other base stations 200.

In addition, the base station 200 of the above embodiment determines the initial value of the transmission power related to the data communication with the other base station 200 based on the use history information of the transmission power related to the data communication with the other base station 200. A processor 250 for setting, and an antenna for data communication with another base station 200 based on the set initial value of transmission power.

Thereby, the base station 200 can reduce the occurrence of communication interference with the surrounding base stations 200. For example, the base station 200 can suppress communication interference even if a large number of base stations 200 (for example, small cell base stations 200B) are added. Further, by making the backhaul line wireless, the cost for adding the base station 200 can be reduced, the economy can be improved, and the speed of installation of the base station can be improved. Further, the base station 200 can reduce the probability of assigning excessive transmission power as an initial value for the own station by referring to the past successful communication examples by the own station, and can suppress the occurrence of communication interference. In addition, the base station 200 can reduce the probability of assigning an excessively small transmission power as an initial value by referring to past communication success examples by the own station, and can suppress deterioration in communication quality.

In addition, the base station 200 may include a memory 260 that stores information on the transmission power usage history related to data communication with other base stations 200. The processor 250 may update the transmission power usage history information stored in the memory 260 based on the transmission power used for data communication by the antenna.

Thus, every time the base station 200 performs data communication via the wireless backhaul line 20, the latest transmission power usage history can be reflected. Thereby, the base station 200 can suppress an increase in communication interference even if the number of installed base stations increases.

In addition, the processor 250 may prioritize transmission power with a large usage history and set transmission power related to data communication with another base station 200.

Thereby, the base station 200 can set the transmission power that is highly likely to succeed in data communication, so that the data communication accuracy can be improved.

Further, the antenna may include a plurality of antennas. The processor 250 controls the power supplied to each of the plurality of antennas based on the wireless communication scheme adopted by the other base station 200 and the set initial value of the transmission power for the plurality of antennas. May be. The plurality of antennas are, for example, MIMO antennas # A11 to # A18, # B11 to # B18.

Thereby, the base station 200 can form the directivity related to data communication determined by the wireless communication method. Even when base station 200 forms directivity, base station 200 can maintain transmission power appropriately and suppress communication interference via wireless backhaul line 20.

Also, the transmission power usage history information may include transmission power information at a radio frequency assigned to data communication and information on the frequency of data communication using this transmission power.

Further, the transmission power information may include information on average power per predetermined time of transmission power used for data communication.

This makes it less susceptible to noise, etc. that occurred in a short time during data transmission, and improves the initial setting accuracy of transmission power.

Moreover, the base station 200 may include an interface for acquiring change information for changing the transmission power usage history. The processor 250 may change the transmission power usage history based on the change information.

Thereby, although the use history (actual result) of the transmission power is large, the base station 200 intentionally refreshes the use history even when the transmission power is not totally optimal (suboptimal case), and is in a suboptimal state. The convergence to can be lifted.

In addition, the transmission power setting method of the above embodiment is a transmission power in the base station 200 that communicates with another base station 200 via the wireless backhaul line 20 in which a plurality of wireless communication methods are mixedly used. It is a setting method. In this method, an initial value of transmission power related to data communication with another base station 200 is set based on information on a transmission power usage history related to data communication with another base station 200, and the set transmission power is set. Data communication is performed with another base station 200 based on the initial value of power.

The present disclosure is useful for a radio communication apparatus, a frequency allocation method, and the like that can improve allocation efficiency and usage efficiency of radio resources for communicating data via a backhaul line.

10 radio communication system 21 uplink 22 downlink 100 terminal 200 base station 200A macro cell base station 200B small cell base station 201 first interface 202 first packet generator 203 first radio transmitter 204 first transmitter antenna 205 first receiver antenna 206 first radio reception unit 207 first packet decoding unit 208 first radio resource management unit 221 second interface 222 second packet generation unit 223 second radio transmission unit 224 second transmission antenna 225 second reception antenna 226 second radio reception Unit 227 second packet decoding unit 228 second radio

resource management unit

250, 250A,

250B processor

260, 260A, 260B memory 300 host device T11, T12, T21, T22 history database

Claims

A wireless communication device that communicates with other wireless communication devices via a wireless backhaul line that is used in combination with a plurality of wireless communication methods,
A processor for allocating a radio frequency for data communication with the other radio communication device based on information on a radio frequency use history for data communication with the other radio communication device;
An antenna that performs data communication with the other wireless communication device using the assigned radio frequency;
A wireless communication device comprising:
The wireless communication device according to claim 1, further comprising:
A memory for storing information on the use history of radio frequency related to data communication with the other radio communication device;
The processor updates the radio frequency usage history information stored in the memory based on a radio frequency used for the data communication by the antenna and a usage history of the radio frequency. apparatus.
The wireless communication device according to claim 1 or 2,
The wireless communication device, wherein the processor assigns a wireless frequency related to data communication with the other wireless communication device in preference to a wireless frequency with a large usage history.
The wireless communication device according to any one of claims 1 to 3,
The radio frequency use history information includes a data communication amount using the radio frequency, a data communication time using the radio frequency, or a data communication count using the radio frequency.
The wireless communication device according to any one of claims 1 to 4,
The processor is
Based on the use history of the radio frequency related to data communication with the other radio communication device, the radio frequency allocation candidate related to data communication with the other radio communication device is derived,
If the allocation candidate radio frequency cannot be allocated, allocate another radio frequency,
The antenna is a wireless communication device that performs data communication with the other wireless communication device using the other wireless frequency.
The wireless communication device according to any one of claims 1 to 5, further comprising:
An interface for acquiring change information for changing the use history of the radio frequency;
The processor is a wireless communication device that changes a use history of the radio frequency based on the change information.
A frequency allocation method in a wireless communication device that communicates with another wireless communication device via a wireless backhaul line that is used in combination with a plurality of wireless communication methods,
Based on the information of the use history of the radio frequency related to data communication with the other radio communication device, the radio frequency related to data communication with the other radio communication device is allocated,
A frequency allocation method for performing data communication with the other radio communication device using the allocated radio frequency.