The present technology relates to a wireless communication device and a wireless communication method, and more particularly to a wireless communication device and a wireless communication method suitable for use when performing wireless communication using a plurality of wireless base stations (access points).
Background technology
[0002]
　Conventionally, in a wireless LAN system using a plurality of access points (wireless base stations), the management server has collected various operational information from each access point and terminal (wireless terminal station) for each cell of each access point. It is disclosed that the average amount of interference is displayed on a display device (see, for example, Patent Document 1).
Prior art literature
Patent documents
[0003]
Patent Document 1: Japanese Patent Application Laid-Open No. 2008-535398
Outline of the invention
Problems to be solved by the invention
[0004]
　However, in the invention described in Patent Document 1, since each terminal cannot grasp the amount of interference of each access point, it is difficult to select an appropriate connection destination so as to reduce the influence of interference, for example.
[0005]
　The present technology has been made in view of such a situation, and enables a wireless terminal station to easily select an appropriate connection destination from a plurality of wireless base stations.
Means to solve problems
[0006]
　The wireless communication device of the first aspect of the present technology includes an observation unit for observing interfering radio waves and a communication unit for transmitting a notification signal including interference information indicating the state of radio wave interference, and includes a plurality of radio base stations. It functions as one of the radio base stations of the radio communication system.
[0007]
　The wireless communication method of the first aspect of the present technology is a wireless communication system in which a wireless communication device observes an interfering radio wave, transmits a notification signal including interference information indicating the state of the interfering radio wave, and includes a plurality of radio base stations. Functions as one of the radio base stations of the above.
[0008]
　The wireless communication device of the second aspect of the present technology includes a communication unit that receives a notification signal including interference information indicating the state of interference radio waves from a plurality of wireless base stations, and functions as a wireless terminal station.
[0009]
　In the first aspect of the present technology, an interfering radio wave is observed, and a notification signal including interference information indicating the state of the interfering radio wave is transmitted.
[0010]
　In the second aspect of the present technology, a notification signal including interference information indicating the state of interference radio waves is received from a plurality of radio base stations.
The invention's effect
[0011]
　According to the first aspect or the second aspect of the present technology, the wireless terminal station can easily select an appropriate connection destination from a plurality of wireless base stations.
[0012]
　The effects described here are not necessarily limited, and may be any of the effects described in the present disclosure.
A brief description of the drawing
[0013]
[Fig. 1] Fig. 1 is a block diagram showing a configuration example of a wireless communication device (access point) to which this technology is applied.
[Fig. 2] Fig. 2 is a block diagram showing a configuration example of a wireless communication device (station) to which this technology is applied.
[Fig. 3] Fig. 3 is a flowchart for explaining an access point connection process.
FIG. 4 is a sequence diagram showing a first example of a protocol between an access point and a station.
[Fig. 5] Fig. 5 is a diagram showing an example of a beacon frame format.
[Fig. 6] Fig. 6 is a flowchart for explaining a station connection process.
[Fig. 7] Fig. 7 is a flowchart for explaining a station connection process.
[Fig. 8] Fig. 8 is a diagram for explaining a method of selecting a station connection destination.
[Fig. 9] Fig. 9 is a diagram for explaining a method of selecting a station connection destination.
FIG. 10 is a flowchart for explaining a transmission strength control process.
[Fig. 11] Fig. 11 is a diagram for explaining a method of controlling the transmission strength of the access point.
FIG. 12 is a sequence diagram showing a second example of a protocol when connecting an access point and a station.
[Fig. 13] Fig. 13 is a diagram showing a configuration example of a computer.
Mode for carrying out the invention
[0014]
　Hereinafter, modes for implementing the present technology will be described. The explanation will be given in the following order.
　1. 1. Embodiment
　2. Modification example
　3. others
[0015]
　<< 1. Embodiment >>
　This technology conforms to, for example, the IEEE 802.11 (wireless LAN) standard, and in a wireless communication system including a plurality of wireless base stations, a wireless terminal station can appropriately connect from a plurality of wireless base stations. The destination is selected to suppress the influence of interfering radio waves (hereinafter, simply referred to as interference) and improve communication quality.
[0016]
　Hereinafter, the wireless base station is referred to as an access point or AP, and the wireless terminal station is referred to as a station or STA.
[0017]
　　
　FIG. 1 is a block diagram showing a configuration example of a wireless communication device 101 to which the present technology is applied.
[0018]
　The wireless communication device 101 functions as an access point and wirelessly communicates with other access points and stations.
[0019]
　Further, the wireless communication device 101 communicates with another server (not shown) or the like via one or more of other access points, a backhaul, and a core communication network such as the Internet. Note that in FIG. 1, the portion where the wireless communication device 101 communicates with another server or the like is not shown.
[0020]
　The wireless communication device 101 includes a communication module 111 and a data processing unit 112.
[0021]
　The communication module 111 wirelessly communicates with other access points and stations.
[0022]
　The data processing unit 112 extracts various information from the signal supplied from the communication module 111, and supplies the extracted information, the generated information, and the like to the communication module 111.
[0023]
　The communication module 111 includes an antenna 121 and a wireless communication module 122.
[0024]
　The antenna 121 wirelessly transmits various signals supplied from the wireless communication module 122. Further, the antenna 121 receives the signal transmitted wirelessly and supplies the signal to the wireless communication module 122.
[0025]
　The wireless communication module 122 is made of, for example, a semiconductor chip or the like. The wireless communication module 122 appropriately supplies and exchanges information with the data processing unit 112, supplies various signals to the antenna 121 for transmission, and performs processing according to the signal received by the antenna 121.
[0026]
　The wireless communication module 122 includes a communication unit 131 and a control unit 132.
[0027]
　The communication unit 131 wirelessly communicates with other access points and stations via the antenna 121 under the control of the control unit 132.
[0028]
　The control unit 132 controls the operation of the entire wireless communication module 122.
[0029]
　The communication unit 131 includes an antenna sharing unit 141, an RF receiving unit 142, a digital signal conversion unit 143, a signal receiving unit 144, a signal generation unit 145, an analog signal conversion unit 146, and an RF transmitting unit 147.
[0030]
　The antenna sharing unit 141 is a switch that switches between transmission and reception. That is, the antenna sharing unit 141 supplies the signal supplied from the RF transmitting unit 147 to the antenna 121, and supplies the signal supplied from the antenna 121 to the RF receiving unit 142.
[0031]
　The RF receiving unit 142 includes, for example, a low noise amplifier, an AGC (Auto Gain Control) unit, a frequency converter, a filter, and the like, and receives a signal by the antenna 121 via the antenna sharing unit 141. The RF receiving unit 142 appropriately performs various processing such as amplification processing, gain adjustment processing, frequency conversion processing, and filtering processing on the received signal, and the signal obtained as a result is transmitted to the digital signal conversion unit 143. Supply. The RF receiving unit 142 also obtains the reception strength of the received signal and supplies it to the control unit 132, if necessary.
[0032]
　The digital signal conversion unit 143 converts the signal supplied from the RF reception unit 142 into a digital signal from an analog signal by AD (Analog Digital) conversion, and supplies the signal to the signal reception unit 144.
[0033]
　The signal receiving unit 144 performs various processes such as demodulation and decoding on the signal supplied from the digital signal conversion unit 143 under the control of the control unit 132, and supplies the signal obtained as a result to the control unit 132.
[0034]
　The signal generation unit 145 performs coding processing or the like based on the information or the like supplied from the control unit 132 to generate a signal in a predetermined format, and also performs modulation processing on the generated signal to modulate the signal. Is supplied to the analog signal conversion unit 146.
[0035]
　The analog signal conversion unit 146 converts the signal supplied from the signal generation unit 145 from a digital signal to an analog signal by DA (Digital Analog) conversion, and supplies the signal to the RF transmission unit 147.
[0036]
　The RF transmitter 147 includes, for example, a frequency converter, an amplifier, a filter, and the like. The RF transmission unit 147 performs frequency conversion processing, amplification processing, filter processing, etc. on the signal supplied from the analog signal conversion unit 146 and supplies the signal to the antenna 121 via the antenna sharing unit 141 to transmit the signal. ..
[0037]
　The control unit 132 includes a communication control unit 151 and an observation unit 152.
[0038]
　The communication control unit 151 controls the communication processing of the wireless communication module 122. Further, for example, the communication control unit 151 supplies the signal supplied from the communication unit 131 to the data processing unit 112, or supplies the information supplied from the data processing unit 112 to the communication unit 131. Further, for example, the communication control unit 151 controls the communication unit 131 (RF transmission unit 147 of the communication control unit 131) to control the strength of the signal transmitted from the antenna 121.
[0039]
　The observation unit 152 observes the interference around the wireless communication device 101 based on the signal from the signal reception unit 144. That is, the observation unit 152 observes the frequency and intensity of a signal (interference signal) received from other than the connected access point and station. The observation unit 152 stores data indicating the observed interference status in a storage unit (not shown), if necessary.
[0040]
　　
　FIG. 2 is a block diagram showing a configuration example of the wireless communication device 201 to which the present technology is applied. In the drawings, the parts corresponding to the wireless communication device 101 of FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted as appropriate.
[0041]
　The wireless communication device 201 functions as a station and wirelessly communicates with the access point.
[0042]
　The wireless communication device 201 includes a communication module 211 and a data processing unit 212.
[0043]
　The communication module 211 performs wireless communication with the access point.
[0044]
　The data processing unit 212 extracts various information from the signal supplied from the communication module 211, and supplies the extracted information, the generated information, and the like to the communication module 211.
[0045]
　The communication module 211 is different from the communication module 111 of FIG. 1 in that the wireless communication module 221 is provided instead of the wireless communication module 122.
[0046]
　The wireless communication module 221 is made of, for example, a semiconductor chip or the like. The wireless communication module 221 supplies various signals to the antenna 121 for transmission while appropriately exchanging information with the data processing unit 212, and performs processing according to the signal received by the antenna 121.
[0047]
　The wireless communication module 221 is different from the wireless communication module 122 of FIG. 1 in that a control unit 231 is provided instead of the control unit 132.
[0048]
　The control unit 231 controls the operation of the entire wireless communication module 221.
[0049]
　The control unit 231 includes a communication control unit 241 and an observation unit 242.
[0050]
　The communication control unit 241 controls the communication processing of the wireless communication module 221. Further, for example, the communication control unit 241 supplies the signal supplied from the communication unit 131 to the data processing unit 212, or supplies the information supplied from the data processing unit 212 to the communication unit 131. Further, for example, the communication control unit 241 controls the communication unit 131 (RF transmission unit 147) to control the strength of the signal transmitted from the antenna 121. Further, for example, the communication control unit 241 selects an access point to which the wireless communication device 201 is connected.
[0051]
　The observation unit 242 starts observing the interference around the wireless communication device 201 based on the signal from the signal reception unit 144. That is, the observation unit 242 observes the frequency and intensity of the signal (interference radio wave) received from other than the connected access point. The observation unit 242 stores data indicating the observed interference status in a storage unit (not shown) as necessary.
[0052]
　　
　Next, the connection process of the access point (wireless communication device 101 of FIG. 1) will be described with reference to the flowchart of FIG. 3 and the sequence diagram of FIG.
[0053]
　The flowchart of FIG. 4 mainly shows the process of connecting the access point to the station, and the description of other processes (for example, disconnection process) is omitted as appropriate.
[0054]
　Further, this process starts when the power of the access point is turned on and ends when the power of the access point is turned off, for example.
[0055]
　In step S1, the observation unit 152 starts observing the interference. Specifically, the observation unit 152 starts observing the frequency, intensity, and the like of the signal (interfering radio wave) received from other than the connected access point and station based on the signal supplied from the signal reception unit 144. The observation unit 152 stores data indicating the observed interference status in a storage unit (not shown), if necessary.
[0056]
　It should be noted that the observation of interference does not necessarily have to be performed constantly, and may be performed intermittently.
[0057]
　In step S2, the communication control unit 151 determines whether or not it is the timing to transmit the Beacon frame. For example, each access point periodically transmits a beacon frame, which is a notification signal, at predetermined intervals, and when the communication control unit 151 determines that it is the timing to transmit the beacon frame, the process proceeds to step S3. move on.
[0058]
　In step S3, the access point transmits a beacon frame.
[0059]
　Specifically, the communication control unit 151 supplies the information stored in each field of the beacon frame to the signal generation unit 145, and instructs the signal generation unit 145 to generate the beacon frame.
[0060]
　The signal generation unit 145 generates a beacon frame based on the information supplied from the communication control unit 151, and supplies the beacon frame to the RF transmission unit 147 via the analog signal conversion unit 146.
[0061]
　The RF transmission unit 147 transmits a beacon frame via the antenna sharing unit 141 and the antenna 121.
[0062]
　After that, the process proceeds to step S4.
[0063]
　FIG. 5 shows an example of the beacon frame format.
[0064]
　The beacon frame is a frame type (Frame Type), period (Duration), receiver address (Receiver Address), transmitter address (Transmitter Address), beacon body (Beacon body), and FCS (Frame Check Sequence) fields. including.
[0065]
　The frame type is a field for storing information indicating the type of frame, and information indicating that it is a beacon frame is set.
[0066]
　The period is a field for storing information indicating the length of the frame transmission period and the like.
[0067]
　The destination address is a field that stores the address (eg, MAC address) of another access point or station that receives the frame. Since the beacon frame is broadcast without specifying the reception destination, the broadcast address is stored.
[0068]
　The source address is a field that stores the address (for example, MAC address) of the access point or station that is the source of the frame. Here, the address of the access point that is the source of the beacon frame is stored.
[0069]
　The beacon body is a field that stores various types of information transmitted by the beacon frame. The beacon body contains, for example, interference info.
[0070]
　The interference information is information indicating the state of interference at the access point. The interference information includes, for example, Channel Interference Info.
[0071]
　The channel interference information is information indicating the state of interference for each subchannel of the access point. The channel interference information of each subchannel includes a channel ID (Channel ID) and one or more detailed information (Detailed Info).
[0072]
　Here, the sub-channel is the smallest unit that uses the media (frequency resources) that can be used by the access point, and the media that can be used by the access point is divided into a plurality of sub-channels for each predetermined bandwidth. ..
[0073]
　The channel ID is an ID for identifying each sub-channel.
[0074]
　The detailed information is information indicating the details of the interference situation of each subchannel. The detailed information includes the interference type and the interference strength.
[0075]
　The interference type is information indicating the type of interference. The types of interference are classified according to, for example, the source and cause of the interference. For example, interference types are classified into IEEE 802.11 systems, microwave ovens, LTE (Long Term Evolution) -LAA (Licensed-Assisted Access), and the like. Further, for example, the IEEE 802.11 system may be classified in more detail by network ID (for example, BSS ID, BSS Color).
[0076]
　The interference strength is information indicating the strength (electric power) of the type of interference indicated by the type of interference. The interference intensity indicates, for example, the distribution of the intensity of interference per unit time (for example, 1 second).
[0077]
　For example, the interference intensity indicates the distribution of the interference intensity observed within a unit time. More specifically, the interference intensity indicates the ratio of each intensity of the time when interference is observed within a unit time. For example, the intensity of interference is divided into a plurality of classes (intensity range) within a predetermined range of class widths, and the ratio of the time in which interference of each class (intensity of each range) is observed within a unit time (hereinafter, time). The occupancy rate) is shown. For example, if the unit time is 1 second and the total time during which the intensity interference within the class x1 is observed is 400 milliseconds, the time occupancy rate of the intensity interference within the class x1 is 40%.
[0078]
　Alternatively, for example, the interference intensity indicates the frequency distribution of the interference intensity observed within a unit time. For example, the number of interferences observed in a unit time is shown for each class (intensity range).
[0079]
　Alternatively, for example, the interference intensity indicates the time series distribution of the interference observed within a unit time. For example, the intensities of interference observed within a unit time are shown in chronological order in the order of observation.
[0080]
　When a plurality of types of interference are observed in a certain subchannel, a plurality of detailed information is stored in the channel interference information of the subchannel for each type of interference.
[0081]
　The FCS is a field that stores a frame check sequence.
[0082]
　Returning to FIG. 3, on the other hand, if it is determined in step S2 that it is not the timing to transmit the beacon frame, the process of step S3 is skipped and the process proceeds to step S4.
[0083]
　In step S4, the communication control unit 151 determines whether or not a probe request frame has been received.
[0084]
　For example, when the RF receiving unit 142 receives the probe request frame transmitted from the station in step S53 of FIG. 6 described later via the antenna 121 and the antenna sharing unit 141, the digital signal conversion unit 143 and the signal receiving unit 144 A probe request frame is supplied to the communication control unit 151 via the above. As a result, the communication control unit 151 determines that the probe request frame has been received, and the process proceeds to step S5.
[0085]
　In step S5, the access point sends a probe response frame.
[0086]
　Specifically, the communication control unit 151 supplies the information stored in each field of the probe response frame to the signal generation unit 145, and instructs the signal generation unit 145 to generate the probe response frame.
[0087]
　The signal generation unit 145 generates a probe response frame based on the information supplied from the communication control unit 151, and supplies the probe response frame to the RF transmission unit 147 via the analog signal conversion unit 146.
[0088]
　The probe response frame includes at least the interference information shown in FIG. In addition, the address of the station that is the source of the probe request frame is set in the destination address.
[0089]
　The RF transmission unit 147 transmits a probe response frame, which is a notification signal, via the antenna sharing unit 141 and the antenna 121.
[0090]
　After that, the process proceeds to step S6.
[0091]
　On the other hand, if it is determined in step S4 that the probe request frame has not been received, the process of step S5 is skipped and the process proceeds to step S6.
[0092]
　In step S6, the communication control unit 151 determines whether or not the connection is requested from the station. If it is determined that the connection is not requested from the station, the process returns to step S2.
[0093]
　After that, in step S6, the processes of steps S2 to S6 are repeatedly executed until it is determined that the connection is requested from the station.
[0094]
　On the other hand, in step S6, when the RF receiving unit 142 receives the Authentication Request frame transmitted from the station in step S61 of FIG. 7, which will be described later, via the antenna 121 and the antenna sharing unit 141, The authentication request frame is supplied to the communication control unit 151 via the digital signal conversion unit 143 and the signal reception unit 144. As a result, the communication control unit 151 determines that the connection has been requested from the station, and the process proceeds to step S7.
[0095]
　In step S7, the access point performs the connection process.
[0096]
　Although detailed description is omitted, the access point performs connection processing with the station requesting the connection according to the protocol shown in FIG.
[0097]
　First, the access point sends an authentication response frame to the station in response to the received authentication request frame.
[0098]
　The access point then receives an Association Request frame from the station and, in response, sends an Association Response frame to the station.
[0099]
　The access point then exchanges the encryption key with the station.
[0100]
　The access point then receives an Acck Set Request frame from the station and, in response, sends an Acck Set Response frame to the station.
[0101]
　In this way, the access point establishes a connection with the station. Then, the access point starts exchanging data with the station.
[0102]
　After that, the process returns to step S2, and the processes after step S2 are executed.
[0103]
　　
　Next, referring to the flowcharts of FIGS. 6 and 7 and the sequence diagram of FIG. 4, the station executed in response to the access point process of FIG. 3 (wireless communication device 201 of FIG. 2). ) Connection processing will be described.
[0104]
　The flowcharts of FIGS. 6 and 7 mainly show the process of connecting the station to the access point, and the description of other processes (for example, disconnection process) is omitted as appropriate.
[0105]
　Further, this process starts when the power of the access point is turned on and ends when the power of the access point is turned off, for example.
[0106]
　In step S51, the station observes the beacon frame for a predetermined period of time. That is, the station waits for the beacon frame for a predetermined period and performs the reception processing of the beacon frame transmitted from the station.
[0107]
　In step S52, the communication control unit 241 determines whether or not the beacon frame has been received. If it is determined that the beacon frame has not been received, the process proceeds to step S53.
[0108]
　In step S53, the station transmits a probe request frame.
[0109]
　Specifically, the communication control unit 241 supplies the information stored in each field of the probe request frame to the signal generation unit 145, and instructs the signal generation unit 145 to generate the probe request frame.
[0110]
　The signal generation unit 145 generates a probe request frame based on the information supplied from the communication control unit 241 and supplies the probe request frame to the RF transmission unit 147 via the analog signal conversion unit 146.
[0111]
　Since the probe request frame is broadcast without specifying the reception destination, the broadcast address is stored in the reception address.
[0112]
　The RF transmission unit 147 transmits a probe request frame via the antenna sharing unit 141 and the antenna 121.
[0113]
　In step S54, the station determines whether or not the probe response frame has been received. If it is determined that the probe response frame has not been received, the process returns to step S51.
[0114]
　After that, the processes of steps S51 to S54 are repeatedly executed until it is determined in step S52 that the beacon frame has been received or that the probe response frame has been received in step S54.
[0115]
　On the other hand, in step S54, when the RF receiving unit 142 receives the probe response frame transmitted from the access point in step S5 of FIG. 3 described above via the antenna 121 and the antenna sharing unit 141, the RF receiving unit 142 receives the digital signal conversion unit 143. And the probe response frame is supplied to the communication control unit 241 via the signal reception unit 144. As a result, the communication control unit 241 determines that the probe response frame has been received, and the process proceeds to step S55.
[0116]
　At this time, the station may receive probe response frames from two or more access points.
[0117]
　Further, in step S52, when the RF receiving unit 142 receives the beacon frame transmitted from the access point in step S3 of FIG. 3 described above via the antenna 121 and the antenna sharing unit 141, the RF receiving unit 142 and the digital signal conversion unit 143 and A beacon frame is supplied to the communication control unit 241 via the signal reception unit 144. As a result, the communication control unit 241 determines that the beacon frame has been received, skips the processes of steps S53 and S54, and proceeds to step S55.
[0118]
　At this time, the station may receive the beacon frame from two or more access points.
[0119]
　In step S55, the communication control unit 241 determines whether or not two or more access points have been detected. When the communication control unit 241 receives a beacon frame or a probe response frame from two or more access points, it determines that two or more access points have been detected, and the process proceeds to step S56.
[0120]
　In step S56, the communication control unit 241 determines whether or not the difference in reception strength between the access point having the highest reception strength and the access point with the second access strength is small. Specifically, the communication control unit 241 has the access point with the highest reception strength of the beacon frame or the probe response frame (hereinafter referred to as the strongest access point) and the second access point among the two or more detected access points. The difference in reception intensity between the access point (hereinafter referred to as the runner-up access point) is calculated. Then, when the difference in the calculated reception strength is less than the predetermined threshold value, the communication control unit 241 determines that the difference in the reception strength between the strongest access point and the runner-up access point is small, and the process proceeds to step S57. move on.
[0121]
　The difference in reception strength between the two access points is mainly the difference in communication quality in the direction from each access point to the station.
[0122]
　In step S57, does the communication control unit 241 have a large difference in the amount of interference (interference radio wave amount) between the access point with the highest reception strength (strongest access point) and the second access point (secondary access point)? Judge whether or not.
[0123]
　Specifically, the communication control unit 241 calculates the amount of interference of the strongest access point based on the interference information received from the strongest access point.
[0124]
　For example, the communication control unit 241 calculates the amount of interference for each interference type by calculating the product of the reception strength (RSSI) of the interference (interference radio wave) and the reception period (time) for each interference type. do. Then, the communication control unit 241 calculates the total value or the average value of the interference amount for each interference type as the interference amount of the strongest access point.
[0125]
　Alternatively, for example, the communication control unit 241 detects the maximum value of the reception intensity (RSSI) of the interference (interference radio wave) for each interference type, and accesses the total value or the average value of the maximum values ​​of the reception intensity for each interference type as the strongest access. Calculated as the amount of point interference.
[0126]
　The above is an example of a method for calculating the amount of interference, and other methods may be used.
[0127]
　Further, the communication control unit 241 calculates the amount of interference of the runner-up access point by the same method as that of the strongest access point.
[0128]
　Further, the communication control unit 241 calculates the difference in the amount of interference between the strongest access point and the runner-up access point. Then, when the difference in the calculated interference amount is equal to or greater than a predetermined threshold value, the communication control unit 241 determines that the difference in the amount of interference between the strongest access point and the runner-up access point is large, and the process proceeds to step S58. move on.
[0129]
　The difference in the amount of interference between the two access points is mainly the difference in communication quality in the direction from the station to each access point.
[0130]
　In step S58, the communication control unit 241 selects the access point with the smaller amount of interference as the connection destination. That is, when the difference in reception strength between the strongest access point and the next access point is small and the difference in the amount of interference between the two access points is large, the communication control unit 241 interferes among the two access points. Select the one with the smaller amount as the connection destination. That is, as a condition for selecting the connection destination, the amount of interference is prioritized over the reception strength.
[0131]
　After that, the process proceeds to step S61.
[0132]
　On the other hand, in step S57, when the difference in the calculated interference amount is less than a predetermined threshold value, the communication control unit 241 determines that the difference in the amount of interference between the strongest access point and the runner-up access point is small, and processes the process. Proceeds to step S59.
[0133]
　Further, in step S56, when the difference in the calculated reception strength is equal to or greater than a predetermined threshold value, the communication control unit 241 determines that the difference in reception strength between the strongest access point and the runner-up access point is large, and processes the process. Proceeds to step S59.
[0134]
　In step S59, the communication control unit 241 selects the access point with the maximum reception strength (strongest access point) as the connection destination. That is, when the difference in reception strength between the strongest access point and the runner-up access point is large, the communication control unit 241 of the two access points, regardless of the size of the difference in the amount of interference between the two access points. Select the one with the higher reception strength as the connection destination. Further, when the difference in the amount of interference between the strongest access point and the runner-up access point is small, the communication control unit 241 of the two access points, regardless of the size of the difference in reception strength between the two access points. Select the one with the higher reception strength as the connection destination. That is, as a condition for selecting the connection destination, the reception strength is prioritized over the amount of interference.
[0135]
　After that, the process proceeds to step S61.
[0136]
　On the other hand, if it is determined in step S55 that only one access point has been detected, the process proceeds to step S60.
[0137]
　In step S60, the communication control unit 241 selects the detected access point as the connection destination.
[0138]
　After that, the process proceeds to step S61.
[0139]
　In step S61, the station requests a connection to the access point selected as the connection destination.
[0140]
　Specifically, the communication control unit 241 supplies the information stored in each field of the authentication request frame to the signal generation unit 145, and instructs the signal generation unit 145 to generate the authentication request frame.
[0141]
　The signal generation unit 145 generates an authentication request frame based on the information supplied from the communication control unit 241 and supplies it to the RF transmission unit 147 via the analog signal conversion unit 146.
[0142]
　The address of the access point selected as the connection destination is set in the authentication request frame reception address.
[0143]
　The RF transmission unit 147 transmits an authentication request frame to the selected access point via the antenna sharing unit 141 and the antenna 121.
[0144]
　In step S62, the station performs a connection process.
[0145]
　Although detailed description is omitted, the station performs connection processing with the access point of the connection destination according to the protocol shown in FIG.
[0146]
　First, the station receives an authentication response frame for the transmitted authentication request frame from the access point.
[0147]
　The station then sends an association request frame to the access point, which in turn receives an association response frame from the access point.
[0148]
　The station then exchanges the encryption key with the access point.
[0149]
　The station then sends an acset request frame to the access point, which in turn receives an acset response frame from the access point.
[0150]
　In this way, the station establishes a connection with the access point. Then, the station starts exchanging data with the access point.
[0151]
　In step S63, the communication control unit 241 determines whether or not the connection with the access point has been disconnected. If it is determined that the connection with the access point is not disconnected, the process proceeds to step S64.
[0152]
　In step S64, the communication control unit 241 determines whether or not an access point other than the connected access point has been detected. When the communication control unit 241 has not received the beacon frame from the access point other than the connected access point, the communication control unit 241 determines that the access point other than the connected access point has not been detected, and the process returns to step S63.
[0153]
　After that, the processes of steps S63 and S64 are repeated until it is determined in step S63 that the connection with the access point has been disconnected or that an access point other than the connected access point has been detected in step S64. Will be executed.
[0154]
　On the other hand, in step S64, when the communication control unit 241 receives the beacon frame from the access point other than the connected access point, it determines that the access point other than the connected access point has been detected, and the process proceeds to step S65. move on.
[0155]
　In step S65, the communication control unit 241 determines whether or not the difference in reception strength between the detected access point and the connected access point is small. Specifically, the communication control unit 241 calculates the difference in reception intensity between the detected access point and the connected access point by the same process as in step S56 described above. Then, when the difference in the calculated reception strength is less than a predetermined threshold value, the communication control unit 241 determines that the difference in the reception strength between the detected access point and the connected access point is small, and the process is stepped. Proceed to S66.
[0156]
　The threshold values ​​used in steps S56 and S65 may be set to the same value or may be set to different values.
[0157]
　In step S66, the communication control unit 241 determines whether or not the detected access point has a smaller amount of interference than the connected access point. Specifically, the communication control unit 241 calculates the amount of interference between the detected access point and the access point during communication by the same process as in step S57 described above. Then, when the communication control unit 241 determines that the detected access point has a smaller interference amount than the connected access point, the process proceeds to step S67.
[0158]
　In step S67, the communication control unit 241 determines whether or not the difference in the amount of interference between the detected access point and the connected access point is large. When the difference in the amount of interference between the detected access point and the connected access point is equal to or greater than a predetermined threshold value, the communication control unit 241 determines that the difference between the two is large, and the process proceeds to step S69.
[0159]
　The threshold values ​​used in step S57 and step S67 may be set to the same value or may be set to different values.
[0160]
　On the other hand, in step S65, when the difference in the calculated reception strength is equal to or greater than a predetermined threshold value, the communication control unit 241 determines that the difference in reception strength between the detected access point and the connected access point is large. , The process proceeds to step S68.
[0161]
　In step S68, the communication control unit 241 determines whether or not the detected access point has a higher reception strength than the connected access point. If it is determined that the detected access point has a higher reception strength than the connected access point, the process proceeds to step S69.
[0162]
　In step S69, the communication control unit 241 selects the detected access point as the connection destination.
[0163]
　After that, the process returns to step S61, the processes after step S61 are executed, and the connection process with the detected access point is performed. That is, when the difference in reception intensity between the detected access point and the connected access point is small, and the amount of interference of the detected access point is very small compared to the amount of interference of the connected access point, or , If the reception strength of the detected access point is very large compared to the reception strength of the connected access point, the connection destination is changed from the connected access point to the detected access point.
[0164]
　On the other hand, if it is determined in step S66 that the amount of interference of the detected access point is equal to or greater than the amount of interference of the connected access point, in step S67, the interference between the detected access point and the connected access point. If it is determined that the difference in quantity is small, or if it is determined in step S68 that the reception strength of the detected access point is equal to or less than the reception strength of the connected access point, the process returns to step S63 and steps The processing after S63 is executed. That is, in this case, the access point is not changed.
[0165]
　If it is determined in step S63 that the access point is disconnected, the process returns to step S51, and the processes after step S51 are executed.
[0166]
　Here, a specific example of the method of selecting the connection destination of the station will be described with reference to FIGS. 8 and 9.
[0167]
　8 and 9 show examples of wireless communication systems including access point AP1 to access point AP3. The access point AP1 to the access point AP3 are installed in the rooms 301a to 301c, respectively. The bandwidth, the number of subchannels, and the signal transmission strength of the frequencies that can be used by the access point AP1 to the access point AP3 are all the same.
[0168]
　A doorway 302a is provided in the room 301a. An entrance / exit 302b is provided between the room 301a and the room 301b. An entrance / exit 302c is provided between the room 301a and the room 301c.
[0169]
　For example, as shown in FIG. 8A, when the station STA1 exists near the entrance / exit 302a, the access point AP1 is closest to the station STA1 and the reception intensity from the access point AP1 is maximized. Therefore, the station STA1 selects the access point AP1 as the connection destination.
[0170]
　After that, as shown in B of FIG. 8, when the station STA1 moves to the vicinity of the entrance / exit 302b, the access point AP2 is closest to the station STA1 and the reception intensity from the access point AP2 becomes maximum. Therefore, the station STA1 changes the connection destination from the access point AP1 to the access point AP2. As a result, the transmission distance between the station STA1 and the connection destination access point is shortened, and the communication speed and communication quality are improved.
[0171]
　On the other hand, as shown in FIG. 9, when the amount of interference in the access point AP2 is larger than the amount of interference in the access point AP1 and the difference is large, the station STA1 and the access point AP1 do not change the connection destination. Continue to connect. This prevents the station STA1 from connecting to the access point AP2, which has a large interference, and lowering the communication speed and communication quality.
[0172]
　In this way, the station can easily select an appropriate access point from a plurality of access points based on the interference information of each access point. As a result, for example, the influence of interference can be suppressed and the communication quality can be improved.
[0173]
　　 In the
　above description, an example is shown in which the station selects an access point based on the interference information of each access point. In addition, for example, a range of stations to which each access point can be connected (hereinafter referred to as a cell range) by controlling the transmission intensity of a beacon frame or a probe response frame based on the interference information of each access point. May be adjusted.
[0174]
　Here, the transmission strength control process executed by the access point will be described with reference to the flowchart of FIG.
[0175]
　In step S101, the access point shares interference information with other access points.
[0176]
　Here, an example of a method of sharing interference information between access points will be described.
[0177]
　For example, the communication control unit 151 supplies the information stored in each field of the information sharing frame to the signal generation unit 145, and instructs the signal generation unit 145 to generate the information sharing frame.
[0178]
　The signal generation unit 145 generates an information sharing frame based on the information supplied from the communication control unit 151, and supplies the information sharing frame to the RF transmission unit 147 via the analog signal conversion unit 146.
[0179]
　The information sharing frame includes at least the interference information shown in FIG. Further, since the information sharing frame is broadcast to other access points, the broadcast address is stored in the receiving address.
[0180]
　The RF transmission unit 147 transmits an information sharing frame via the antenna sharing unit 141 and the antenna 121.
[0181]
　Further, the RF receiving unit 142 receives the information sharing frame transmitted from another access point via the antenna 121 and the antenna sharing unit 141, and the communication control unit 142 via the digital signal conversion unit 143 and the signal receiving unit 144. An information sharing frame is supplied to 151.
[0182]
　In this way, the interference information of each access point is shared between the access points.
[0183]
　Note that, for example, information sharing frames may be transmitted and received between access points via a station.
[0184]
　Further, for example, interference information may be transmitted and received between access points via a communication network such as the Internet.
[0185]
　The method of sharing the interference information is arbitrary, and other methods may be used.
[0186]
　In step S102, the communication control unit 151 adjusts the transmission strength. For example, the communication control unit 151 controls the RF transmission unit 147 to adjust the transmission intensity of a frame (for example, a beacon frame, a probe response frame) for transmitting interference information to the station. For example, the transmission intensity is increased as the amount of interference observed by the observation unit 152 is smaller, and is decreased as the amount of interference is larger.
[0187]
　For example, as shown in FIG. 11, when the access point AP1 has a smaller interference amount than the access point AP2, the access point AP1 has a higher transmission intensity than the access point AP2. As a result, the cell range C1 of the access point AP1 becomes larger than the cell range C2 of the access point AP2.
[0188]
　As a result, for example, the influence of interference on communication between the station and the access point can be reduced without performing special processing on the station side.
[0189]
　Note that each access point may adjust the transmission strength relative to each other in cooperation with other access points, or the transmission strength may be adjusted based on the amount of interference without coordinating with other access points. It may be set uniquely.
[0190]
　In the former case, for example, even if the observed interference amount is the same, the transmission intensity is adjusted according to the interference amount of the surrounding access points. For example, the larger the interference amount of the surrounding access points, the higher the transmission strength, and the smaller the interference amount of the surrounding access points, the lower the transmission strength.
[0191]
　Note that, for example, each access point may limit the lower limit of the transmission strength so that the connection with the currently connected station is not disconnected.
[0192]
　<< 2. Modifications >>
　Hereinafter, modifications of the above-described embodiment of the present technology will be described.
[0193]
　In the above description, the communication control unit 241 of the station has shown an example of selecting a connection destination from two access points, the strongest access point and the runner-up access point. For example, three or more access points have been detected. In this case, the connection destination may be selected by comparing the reception strength and the amount of interference of three or more access points.
[0194]
　Further, for example, the communication control unit 241 of the station may select the connection destination based not only on the interference situation observed at the access point but also on the interference situation observed by itself. For example, if the access point has a small amount of interference but the station has a subchannel (corresponding frequency band) with a large amount of interference, the deterioration of communication quality due to interference in the direction from the station to the access point is small, It is expected that the deterioration of communication quality due to the interference in the direction from the access point to the station will be large. In this case, the communication control unit 241 may not use the subchannel.
[0195]
　Further, for example, the communication control unit 151 of each access point may limit the subchannels that can be used based on the observed interference situation. For example, the communication control unit 151 permits the use of the subchannels whose interference amount is less than the threshold value among the subchannels assigned to the access points, and prohibits the use of the subchannels whose interference amount is more than the threshold value. May be good.
[0196]
　Further, for example, as shown in the sequence diagram of FIG. 12, when the access point cannot maintain the communication quality due to a large amount of interference or the like, the station may be requested to change the connection destination. Specifically, the access point may transmit a handover request frame to the station after the connection between the access point and the station is established by the protocol described above with reference to FIG. In response to this, the station disconnects from the access point, searches for another access point, and connects to it.
[0197]
　As a result, it is possible to avoid the influence of interference at the access point and improve the communication quality. However, in this case, the station and the access point need to perform the connection process once. Therefore, according to the method described above, it is possible for the station to connect to an appropriate access point more quickly if the station selects a connection destination based on the interference information and then performs the connection process.
[0198]
　Further, in the above description, an example in which the wireless communication module 122 (FIG. 1) and the wireless communication module 221 (FIG. 2) are configured by a semiconductor chip is shown. For example, the communication module 111 (FIG. 1) and the communication module 211 (FIG. 1) It is also possible to configure each of FIG. 2) with one semiconductor chip.
[0199]
　Further, in the above description, the access point has shown an example of transmitting the interference information by using the beacon frame or the probe request frame, but the interference information may be transmitted by using another notification signal.
[0200]
　In addition to the above-mentioned communication conforming to the IEEE 802.11 standard, this technology can be applied to all types of communication in which a wireless terminal station selects a connection destination from a plurality of wireless base stations for communication. can.
[0201]
　<< 3. Others >>
　　 The
　above-mentioned series of processes can be executed by hardware or software. When a series of processes are executed by software, the programs that make up the software are installed on the computer. Here, the computer includes a computer embedded in dedicated hardware and, for example, a general-purpose personal computer capable of executing various functions by installing various programs.
[0202]
　FIG. 13 is a block diagram showing a configuration example of the hardware of a computer that executes the above-mentioned series of processes programmatically.
[0203]
　In the computer 500, the CPU (Central Processing Unit) 501, the ROM (Read Only Memory) 502, and the RAM (Random Access Memory) 503 are connected to each other by the bus 504.
[0204]
　An input / output interface 505 is further connected to the bus 504. An input unit 506, an output unit 507, a storage unit 508, a communication unit 509, and a drive 510 are connected to the input / output interface 505.
[0205]
　The input unit 506 includes an input switch, a button, a microphone, an image sensor, and the like. The output unit 507 includes a display, a speaker, and the like. The storage unit 508 includes a hard disk, a non-volatile memory, and the like. The communication unit 509 includes a network interface and the like. The drive 510 drives a removable medium 511 such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory.
[0206]
　In the computer 500 configured as described above, the CPU 501 loads the program recorded in the storage unit 508 into the RAM 503 via the input / output interface 505 and the bus 504 and executes the program as described above. A series of processing is performed.
[0207]
　The program executed by the computer 500 (CPU 501) can be recorded and provided on the removable media 511 as a package media or the like, for example. Programs can also be provided via wired or wireless transmission media such as local area networks, the Internet, and digital satellite broadcasts.
[0208]
　In the computer 500, the program can be installed in the storage unit 508 via the input / output interface 505 by mounting the removable media 511 in the drive 510. Further, the program can be received by the communication unit 509 and installed in the storage unit 508 via a wired or wireless transmission medium. In addition, the program can be pre-installed in the ROM 502 or the storage unit 508.
[0209]
　The program executed by the computer may be a program that is processed in chronological order according to the order described in this specification, or may be a program that is processed in parallel or at a necessary timing such as when a call is made. It may be a program in which processing is performed.
[0210]
　Further, in the present specification, the system means a set of a plurality of components (devices, modules (parts), etc.), and it does not matter whether or not all the components are in the same housing. Therefore, a plurality of devices housed in separate housings and connected via a network, and a device in which a plurality of modules are housed in one housing are both systems. ..
[0211]
　Further, the embodiment of the present technology is not limited to the above-described embodiment, and various changes can be made without departing from the gist of the present technology.
[0212]
　For example, the present technology can have a cloud computing configuration in which one function is shared by a plurality of devices via a network and jointly processed.
[0213]
　Further, each step described in the above-mentioned flowchart can be executed by one device or can be shared and executed by a plurality of devices.
[0214]
　Further, when a plurality of processes are included in one step, the plurality of processes included in the one step can be executed by one device or shared by a plurality of devices.
[0215]
　　 The
　present technology can also have the following configurations.
[0216]
(1) One 　of the radio base stations of a radio communication system 　including
　an observation unit for observing interference radio waves and
a communication unit for transmitting a notification signal including interference information indicating the status of interference radio waves, and
　having a
plurality of radio base stations. A
　wireless communication device that functions as a device.
(2) 　The wireless communication device according to (1) above
　, wherein the interference information includes the intensity of the interference radio wave
.
(3) 　The wireless communication device according to (2) above
　, wherein the interference information includes a distribution of the intensity of the interfering radio waves
.
(4) 　The wireless communication device according to (2) or (3) above
　, wherein the interference information includes a type of interfering radio wave
.
(5) 　The wireless communication device according to (4) above
　, wherein the interference information includes the intensity of each type of interference radio wave
.
(6) 　The wireless communication device according to any one of (1) to (4) above
　, wherein the interference information indicates the state of interference radio waves for each subchannel
.
(7)
　A communication control unit that controls the sub-channel to be used based on the state of interference radio waves for each sub-channel.
　The wireless communication device according to (6) above.
(8) 　The wireless communication device according to any one of (1) to (7) above
　,
further comprising a communication control unit that controls the transmission strength of the notification signal based on the condition of the interfering radio wave .
(9) 　The wireless communication device according to (8),
　wherein the communication control unit reduces the transmission intensity of the notification signal as the amount of interference radio waves increases
.
(10) 　The wireless communication device according to (8) or (9),
　wherein the communication control unit further controls the transmission intensity of the notification signal based on the state of interference radio waves of the surrounding wireless base station
.
(11) 　The wireless communication device according to (10),
　wherein the communication unit receives the notification signal from another wireless base station
.
(12) 　The wireless communication device according to any one of (1) to (11) above
　, wherein the notification signal is a beacon frame in the IEEE 802.11 standard
.
(13) The
　wireless communication device
　observes the
　interfering radio waves and transmits a notification signal including interference information indicating the status of the interfering radio waves.
　A
　wireless communication method that functions as one of the wireless base stations of a wireless communication system including a plurality of wireless base stations .
(14) 　A 　wireless communication device that functions as 　a wireless terminal station , including
　a communication unit that receives notification signals including interference information indicating the status of interference radio waves from a plurality of wireless base stations . (15) 　The wireless communication device according to (14), further including 　a communication control unit that selects a connection destination from a plurality of the wireless base stations based on the interference information . (16) The 　connection destination is selected by the communication control unit based on the state of interference radio waves of the plurality of the radio base stations and the reception strength from the plurality of the radio base stations 　. Wireless communication device. (17) The 　communication control unit is used when the difference in reception strength between the strongest radio base station, which is the radio base station having the maximum reception strength, and another radio base station is equal to or greater than the first threshold value, or When the difference in the amount of interference radio waves between the strongest radio base station and the other radio base station is less than the second threshold value, the connection destination is selected based on the reception strength, and the strongest radio base station and the other radio base station are selected. The difference in reception intensity between the radio base station is less than the first threshold value, and the difference in the amount of interference radio waves between the strongest radio base station and the other radio base station is greater than or equal to the second threshold value. In the case of, 　the wireless communication device according to (16), wherein the connection destination is selected based on the amount of interference radio waves .

(18) The 　communication control unit 　further includes
　an observation unit for observing the interference radio wave, and the communication control unit further selects the connection destination based on the observed interference radio wave condition according to 　any one of (15) to (17). Wireless communication device.

[0217]
　It should be noted that the effects described in the present specification are merely examples and are not limited, and other effects may be obtained.
Code description
[0218]
　101 wireless communication device, 111 communication module, 112 data processing unit, 121 antenna, 122 wireless communication module, 131 communication unit, 132 control unit, 142 RF receiver, 147 RF transmitter, 151 communication control unit, 152 observation unit, 201 Wireless communication device, 211 communication module, 212 data processing unit, 221 wireless communication module, 231 control unit, 241 communication control unit, 242 observation unit, AP1 to AP3 access points, STA1 station
The scope of the claims
[Claim 1]
　An observation unit for observing the interference radio wave,
　a communication unit that transmits a broadcast signal including the interference information indicating the status of the interference radio wave
　with a
　function as one of the radio base station of a wireless communication system comprising a plurality of radio base stations to
　the wireless communication device.
[Claim 2]

　The wireless communication device according to claim 1 　, wherein the interference information includes the intensity of the interference radio wave .
[Claim 3]

　The wireless communication device according to claim 2, 　wherein the interference information includes a distribution of the intensity of the interfering radio waves .
[Claim 4]

　The wireless communication device according to claim 2, 　wherein the interference information includes a type of interfering radio wave .
[Claim 5]

　The wireless communication device according to claim 4, 　wherein the interference information includes the intensity of each type of interfering radio wave .
[Claim 6]

　The wireless communication device according to claim 1, 　wherein the interference information indicates a state of interference radio waves for each subchannel .
[Claim 7]

　The wireless communication device according to claim 6, further 　comprising a communication control unit that controls the sub-channel to be used based on the state of interference radio waves for each sub-channel .
[Claim 8]

　The wireless communication device according to claim 1, further comprising 　a communication control unit that controls the transmission strength of the notification signal based on the state of the interfering radio wave .
[Claim 9]

　The wireless communication device according 　to claim 8, wherein the communication control unit reduces the transmission strength of the notification signal as the amount of interference radio waves increases .
[Claim 10]

　The wireless communication device according 　to claim 8, wherein the communication control unit further controls the transmission strength of the notification signal based on the state of interference radio waves of the surrounding wireless base station .
[Claim 11]

　The wireless communication device according 　to claim 10, wherein the communication unit receives the notification signal from another wireless base station .
[Claim 12]

　The wireless communication device according to claim 1, 　wherein the notification signal is a beacon frame in the IEEE 802.11 standard .
[Claim 13]
　Wireless communication device,
　to observe interference radio wave,
　and transmits a broadcast signal including the interference information indicating the status of the interference radio wave,
　and functions as one of the radio base station of a wireless communication system comprising a plurality of radio base station
　radio communication Method.
[Claim 14]
　A 　wireless communication device that functions as
　a
wireless terminal station , including 　a communication unit that receives notification signals including interference information indicating the status of interference radio waves from a plurality of wireless base stations
.
[Claim 15]

　The wireless communication device according to claim 14, further comprising 　a communication control unit that selects a connection destination from the plurality of wireless base stations based on the interference information .
[Claim 16]

　The wireless communication device according 　to claim 15, wherein the communication control unit selects the connection destination based on the state of interference radio waves of the plurality of the wireless base stations and the reception strength from the plurality of the wireless base stations .
[Claim 17]
　The communication control unit is used when the difference in reception strength between the strongest radio base station, which is the radio base station having the maximum reception strength, and another radio base station is equal to or greater than the first threshold value, or the strongest radio. When the difference in the amount of interference radio waves between the base station and the other radio base station is less than the second threshold value, the connection destination is selected based on the reception strength, and the strongest radio base station and the other radio base are selected. When the difference in reception intensity between the stations is less than the first threshold value and the difference in the amount of interference radio waves between the strongest radio base station and the other radio base station is greater than or equal to the second threshold value.
　The wireless communication device according to claim 16, wherein the connection destination is selected based on the amount of interference radio waves .
[Claim 18]
　An observation unit for observing the interference radio wave
　including Moreover,
　the communication control unit selects the connection destination on the basis of the further conditions of the observed interference wave
　radio communication apparatus according to claim 15.