JP5904539B2 - Communication device and communication control method - Google Patents

Description

  The present invention relates to a communication device that is a terminal configured to operate in a television white space (TVWS) environment and a communication control method thereof, and in particular, communication suitable for avoiding contention among secondary users as much as possible. The present invention relates to an apparatus and a communication control method thereof.

  A wireless communication standard that uses the same frequency band as that of licensed television broadcasting and can be operated without a license is being studied. In these standards, a TV user is a primary user, and only when the licensed frequency band of the primary user is not used, the secondary user is allowed to use the frequency band (unused licensed frequency band = white space). Allow to operate wireless communication.

  The secondary user communication device used in such an environment makes an inquiry to the dedicated database regarding the TV channel in order to confirm that there is no TV signal. That is, the current position information of the communication device is transmitted to the database, and a list of channels that can be used (valid) at the position is obtained from the database. Then, a channel to be used is selected from the channels in the list, and wireless communication is performed as a secondary user.

  Therefore, secondary users located very close to each other have a possibility of using the same channel, and have a competitive relationship. That is, when the same channel is actually selected, mutual interference may occur in communication, and communication quality may be impaired. In order to avoid such a situation, for example, the secondary users exchange information directly and select a channel so that the used channel does not compete, or a server for managing coexistence is separately provided and selected. It is conceivable to perform channel selection through channel registration and its inquiry by other secondary users.

  However, even if information is exchanged between secondary users or a server for managing coexistence is provided, it is necessary to newly provide an interface for the communication apparatus, which is a burden. Moreover, even if such an interface is provided, there may be a case where some secondary users do not support information exchange between secondary users, or a server that manages coexistence cannot happen.

FCC R & O 10-174 EU Electronic Communications Committee (ECC) Report Number 159, “Technical and operational requirements for the possible operation of cognitive radio systems in the‘ white space ’of the frequency band 470-790 MHz”, Jan. 2011. IETF RFC 6225

  The present invention relates to a communication device that is a terminal configured to operate in a television white space environment and a communication control method thereof, and a communication device capable of avoiding contention between secondary users as much as possible with a simple configuration. And it aims at providing the communication control method.

  In order to solve the above problems, a communication apparatus according to one aspect of the present invention is a communication apparatus having a communication function unit, the means for specifying the geographical position of the own apparatus, the geographical position, and the geographical position A first index which is either an index indicating the accuracy of the target position or an index indicating an accuracy coarser than the accuracy meant by the index, and an accuracy coarser than the accuracy meant by the first index Means for transmitting a second indicator to a database, a first list that is a list indicating a first available channel available at the geographical location with the first indicator, and the second list Means for obtaining from the database a second list, which is a list indicating a second available channel available at the geographical location with an indicator, and the second usage from the first available channel. Possible From among the channels except for the channel, characterized by comprising means for selecting a channel to be used as available channels, and means for controlling the communication function unit to use the available channels.

  The communication apparatus, following the identification of the geographical position of the own apparatus, a first index which is an index indicating the accuracy of the geographical position (or an index indicating an accuracy coarser than the accuracy meant by the index); The second index indicating accuracy coarser than the accuracy meant by the first index is transmitted to the database. From the database, a first list that is a list showing a first available channel available at a geographical location with a first indicator, and a first list that is available at a geographical location with a second indicator. A second list that is a list showing two available channels is sent.

  Here, the set of channels included in the first list is a set including all the channels included in the second list. In other words, the second list is a subset of the first list (although not necessarily the same). This is inevitably considered in the search process of available channels performed by the database for two regions that are geographically inclusive due to the relationship of the accuracy of the geographical location.

  Therefore, a channel to be used is selected from channels obtained by removing the second available channel from the first available channel. In this way, an available channel with a lower competition rate is selected. The second available channel is a channel that can be commonly used in a wide area, and the competition rate is high accordingly. If an available channel with a low competition rate is selected, the competition between secondary users is inevitably reduced accordingly. Further, the probability that the communication device existing in the adjacent region is different from the channel that is considered to be selected increases, and the possibility of contention also decreases accordingly.

  Further, a communication control method according to another aspect of the present invention is a communication control method in a communication device having a communication function unit, wherein the geographical location of the device itself is specified, and the geographical location and the geographical location A first index which is either an index indicating the accuracy of the index or an index indicating an accuracy coarser than the accuracy meant by the index, and a second indicating an accuracy coarser than the accuracy meant by the first index A first list that is a list showing a first available channel available at the geographical location with the first indicator, and with the second indicator A second list that is a list indicating a second available channel that can be used in the geographical location is acquired from the database, and the second available channel is excluded from the first available channel. From among the panel, and select the channel to be used as available channels, and controlling the communication function unit to use the available channels.

  This communication control method is a control method based on the above-described communication device.

  Advantageous Effects of Invention According to the present invention, in a communication device that is a terminal configured to operate in a television white space environment and a communication control method thereof, it is possible to avoid contention between secondary users as much as possible with a simple configuration. A communication device and a communication control method thereof can be provided.

The functional block diagram which shows the structure of the communication apparatus which is one Embodiment of this invention. The geographical display figure explaining the relationship between the geographical position which the database inquiry part 12 shown in FIG. 1 sends to a database, and its accuracy index. Explanatory drawing which shows the example of a format of the inquiry message which the database inquiry part 12 shown in FIG. 1 transmits to a database. FIG. 4 is an explanatory diagram showing a format example of a message returned from the database corresponding to the format shown in FIG. 3.

  As an embodiment of the present invention, means for storing whether the moving speed of the own apparatus is relatively slow or fast, and when the moving speed of the own apparatus is relatively slow, from the first available channel, the first Means for selecting a channel to be used as a usage channel from among channels other than the two available channels, and when the moving speed of the device is relatively high, the second available channel, And a means for selecting a channel to be used as a usage channel.

  This is to change the choice of the use channel according to the moving speed of the apparatus. When the movement speed is low, the channel is selected as described above, and when the movement speed is high, the use channel is selected from the second available channels. In this way, when the moving speed is high, the channel is selected to be usable in a wider area, so that the frequency of switching the used channel can be greatly suppressed, and communication is likely to be stable.

  As an embodiment, the information processing apparatus may further include means for generating a message including at least the geographical position, the first index, and the second index as an inquiry message to the database. . This is to generate a message so as to make the query to the database more efficient. That is, according to this, it is not necessary to send the first and second indexes to the database at a time, and it is not necessary to make two inquiries.

  Further, as an embodiment, the database includes the geographical position, the first index, the second index, and a third index indicating accuracy coarser than the accuracy meant by the second index. A list indicating a third available channel available at the geographic location with the third indicator, the means for transmitting to the third list, the second list, and the third list. Means for acquiring a list from the database, means for storing whether the movement speed of the own apparatus is relatively slow, medium or fast, and the first apparatus when the movement speed of the own apparatus is relatively slow. When the moving speed of the own device is comparatively medium and the means for selecting the channel to be used as the usage channel from the channels obtained by removing the second available channel from the available channels, the second Profit Means for selecting a channel to be used as a use channel from channels obtained by removing the third available channel from the available channels, and the third use when the moving speed of the own apparatus is relatively high It is possible to further comprise means for selecting a channel to be used as a use channel from among the channels.

  This is to change the choice of the use channel more finely according to the moving speed of the apparatus. When the moving speed is slow, the channel selection is performed as described above, and when the moving speed is medium, the second available channel is excluded from the third available channel. Is selected as a usage channel, and when the moving speed is high, a usage channel is selected from the third available channels. In this way, according to the difference in the moving speed, the channel is selected to be usable in a wider area, so that the frequency of switching the used channel can be greatly suppressed, and communication is likely to be stable. On the other hand, contention among secondary users is also reduced.

  Further, as an embodiment, the apparatus further comprises means for generating a message including at least the geographical position, the first indicator, the second indicator, and the third indicator as an inquiry message to the database. You can. This also generates a message so as to make the inquiry to the database more efficient. That is, according to this, it is not necessary to send the first, second, and third indexes to the database at a time, and it is not necessary to make three inquiries, so that an efficient inquiry is made.

  Based on the above, embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a functional block diagram showing a configuration of a communication apparatus according to an embodiment of the present invention. As shown in the figure, the communication apparatus includes a position specifying unit 11, a database inquiry unit 12, a use channel selection unit 13, a moving speed information storage / holding unit 14, a control unit 15, and a communication function unit 16.

  The position specifying unit 11 specifies the current position of the own apparatus using, for example, a GPS (global positioning system) satellite. The identified current position is passed to the database inquiry unit 12. The current position obtained by the position specifying unit 11 is information on the latitude and longitude (that is, geographical position). The resulting geographical location is potentially associated with its accuracy, depending on the capabilities of the GPS satellite.

  The database inquiry unit 12 obtains the geographical position passed from the position specifying unit 11, an index indicating the accuracy (or an index indicating an accuracy that is coarser than the accuracy implied by the index), and an even coarser accuracy. The indicator to be shown is transmitted to the database. That is, a plurality of indices are transmitted for the accuracy of the geographical location. A plurality of indicators may be transmitted at once or divided into a plurality of indicators. The database is a server provided on the Internet so as to provide information on available channels to communication devices that can be operated in a TVWS environment.

  In a normal communication device, it is sufficient to send one index. However, a plurality of indices are transmitted as described above for the following reason. The database searches for available channels at that geographic location, taking into account the accuracy of the queried geographic location. In other words, if the accuracy is high, a search for a channel that can be used only in a substantially narrow area including the geographical position is performed, and if the accuracy is poor, a wider area including the geographical position is performed. Search for available channels in all of. Such a search is necessary for the secondary user to operate wirelessly so as not to interfere with the primary user regardless of the accuracy of the geographical location.

  By utilizing the action of such a database, intentionally, a plurality of indicators are transmitted regarding the accuracy of the geographical location. In this way, in the database, a list of available channels is generated for each accuracy index, and the plurality of lists are sent to the database inquiry unit 12. The multiple lists have the following properties. That is, the set S2 of available channels included in the list L2 corresponding to the index of inaccuracy is always a subset of the set S1 of available channels included in the list L1 corresponding to the index of higher accuracy. (Same case is considered) (S1⊇S2). The former is generally multi-channel because it only needs to be available in a narrow area, and the latter has a smaller number of channels because it must be available all over a larger area.

  When the database inquiry unit 12 acquires a plurality of lists L1 and L2, if the communication device is a normal communication device, the channel included in the list L1 presented as a multi-channel is simply an option to be selected. By using it, it becomes possible to make a more valuable selection that avoids competition among secondary users as much as possible (described in the description of the next usage channel selection unit 13). A plurality of lists acquired from the database by the database inquiry unit 12 are transferred to the use channel selection unit 13.

  The use channel selection unit 13 uses the plurality of lists L1 and L2 passed from the database inquiry unit 12 to generate channel options to be selected as follows. That is, a product set of a set of channels that do not belong to L2 (complement set of S2) and a set S1 of channels that belong to L1 is generated as an option of a channel to be selected. In other words, the option is a set of channels excluding L1 from L1.

  If such an option is generated, an available channel with a lower competition rate is selected. The available channels included in L2 are channels that can be commonly used in a wide area, and the competition rate that is considered to be selected is high. If an available channel with a low competition rate is selected, the competition between secondary users is inevitably reduced accordingly. Further, the probability that the communication device existing in the adjacent region is different from the channel that is considered to be selected increases, and the possibility of contention also decreases accordingly.

  The use channel selection unit 13 selects a channel to be used as a use channel from the options generated as described above. A plurality of use channels may be selected as long as it is convenient for communication with this apparatus. Information on the selected usage channel is passed to the control unit 15.

  The movement speed information storage / holding unit 14 is a storage unit that stores and holds whether the movement speed of the device itself is relatively slow or fast. This storage holding unit 14 is optional or not provided. The advantage of the provision is that it is possible to change the channel options in the use channel selection unit 13 by sending information to the use channel selection unit 13 about whether the moving speed of the own apparatus is relatively slow or fast. is there.

  When the moving speed is slow (for example, a communication device with a fixed position or a communication device carried by a pedestrian), the use channel selection unit 13 selects a channel as described above. When the moving speed is high (for example, a communication device moving on a high-speed railway), unlike the above, a use channel is selected from L2. In this way, when the moving speed is high, the channel is selected to be usable in a wider area, so that the frequency of switching the used channel can be greatly suppressed, and communication is likely to be stable. However, even if the moving speed is high, communication is not impossible even if channel selection is performed using a set of channels excluding L1 to L2 as an option, and only frequent switching of used channels occurs.

  In order to hold the information in the movement speed information storage / holding section 14, a means for detecting the movement speed of the own apparatus may be provided, and the output of the means may be guided to the movement speed information storage / holding section 14. . The detection of the moving speed can be realized by providing means for detecting the geographical position output by the position specifying unit 11 every moment. In the case of a communication device that is determined to be operated as a fixed-position communication device, information indicating that the moving speed of the own device is relatively slow is held in the moving speed information storage holding unit 14 or moved. The speed information storage / holding unit 14 itself may be omitted.

  The control unit 15 controls the communication function unit 16 based on the information on the usage channel passed from the usage channel selection unit 13. That is, the communication function unit 16 performs wireless transmission / reception using this usage channel. The communication function unit 16 is a function unit having an original communication function.

  The configuration and operation of one embodiment have been described above. In a communication apparatus operated in a TVWS environment, generally, for example, a secondary user exchanges information and selects a channel so that a used channel does not compete, or a server for managing coexistence is separately provided. It is conceivable to select and select a channel through registration of the selected channel and its inquiry by another secondary user. In any case, however, it is necessary to newly provide an interface for the communication device, which is a burden. Even if such an interface is provided, some secondary users may not be able to exchange information between secondary users, or a server that manages coexistence may not happen. In the above embodiment, there is an effect of easily solving such a point.

  In the above description of the embodiment, a case has been described in which the database inquiry unit 12 acquires two lists as a plurality of lists. However, the configuration is expanded so that three or more lists are acquired with the same idea. It can also be applied. According to this, it is possible to change the choice of the use channel more finely according to the moving speed of the apparatus.

  That is, for example, when acquiring three lists, it is as follows. First, the database inquiry unit 12 includes a first index that indicates a geographical position, a relatively high accuracy, a second index that indicates a medium accuracy, and a relatively low accuracy. The third index indicating the sex is transmitted to the database. The database sends to the database inquiry unit 12 the first list corresponding to the first index, the second list corresponding to the second index, and the third list corresponding to the third index. Therefore, the inquiry unit 12 acquires this.

  The movement speed information storage / holding unit 14 stores and holds whether the movement speed of the apparatus itself is relatively slow, medium, or fast. When the moving speed of the own device is relatively slow, the use channel selection unit 13 tries to use the channel from the available channels in the first list excluding the available channels in the second list. Select the channel you want to use as the usage channel. Also, when the moving speed of the own device is in the middle of comparison, the channel to be used is used from the channels obtained by excluding the available channels in the third list from the available channels in the second list. Select as a channel. Furthermore, when the moving speed of the own device is relatively high, the channel to be used is selected as the use channel from the available channels in the third list.

  In this way, according to the difference in the moving speed, the channel is selected to be usable in a wider area, so that the frequency of switching the used channel can be greatly suppressed, and communication is likely to be stable. On the other hand, the effect that the competition between secondary users becomes smaller is also maintained.

  Each embodiment described above can be applied to, for example, an IEEE 802.11af apparatus. The database and the interface with the communication device mentioned in the embodiment can be operated according to the same standard. In addition, the same idea can be applied to an autonomous coexistence system such as IEEE 802.19.1 in order to supplement its function.

  Next, FIG. 2 is a geographical display diagram for explaining the relationship between the geographical position sent to the database by the database inquiry unit 12 shown in FIG. 1 and its accuracy index. With reference to FIG. 2, the accuracy of the geographical location will be supplementarily described.

  As described above, the geographical position is specified by the longitude and latitude. The fact that an accuracy index is attached to the geographical position is substantially divided by the upper and lower longitudes and the upper and lower latitudes according to the “first index”, as shown in FIG. This means that the communication device is located in the rectangular area A1. As shown in FIG. 2, if the “second index” indicating the coarser accuracy than the meaning of the “first index” is associated with the same geographical position, It is located in the rectangular area A2 divided by the upper and lower longitudes and the upper and lower latitudes.

  Since the area A1 is included in the area A2, inevitably, a subset of the set of available channels effective in A1 (which may be the same) becomes a set of available channels effective in A2. In other words, the former is generally multi-channel because it only needs to be available in a narrow area, and the latter has a smaller number of channels because it must be available in all of the larger area.

The accuracy of the geographical position can be indicated by a value represented by 28 ^-x based on a standard defined in IETF RFC 6225, for example. Here, x is a 6-bit value (= 0 to 63), and 2 ^8-x is in the range of 2 ⁸ to ^2-55 (64 levels). In this standard, if the x value is given in addition to the geographical position, the upper and lower latitudes and the upper and lower latitudes shown in FIG. 2 are given.

  Next, FIG. 3 is an explanatory diagram showing a format example of an inquiry message transmitted from the database inquiry unit 12 shown in FIG. 1 to the database. The format of the inquiry message transmitted to the database will be supplementarily described with reference to FIG.

  As shown in FIG. 3, the database inquiry unit 12 uses, as an inquiry message to the database, for example, a message including the device identifier, its geographical position, the number of indicators to be sent, indicators A, indicators B, indicators C,. Generate. In this way, the indexes A, B, C,... Are transmitted to the database at a time, and it is not necessary to make multiple inquiries, so that an efficient inquiry is made. When this is applied to the first embodiment described with reference to FIG. 1, the number of indices to be sent is 2, and the indices A and B are included in the format.

  Next, FIG. 4 is an explanatory diagram showing a format example of a message returned from the database corresponding to the format shown in FIG. The format of the message returned from the database will be supplementarily described with reference to FIG.

  As shown in FIG. 4, a list of available channels is generated for each accuracy index and included in the format of the reply message. Each available channel may be accompanied by information on its valid time and available maximum power. This point is based on each wireless communication standard premised on operating in a TVWS environment. The control unit 15 controls the communication function unit 16 so that the operation of the communication device function unit 16 does not violate the information on the effective time and the maximum power that can be used.

  DESCRIPTION OF SYMBOLS 11 ... Position specification part, 12 ... Database inquiry part, 13 ... Utilization channel selection part, 14 ... Movement speed information storage holding part, 15 ... Control part, 16 ... Communication function part

Claims (6)

A communication device having a communication function unit,
Means for identifying the geographical location of the device;
The first index means the geographical position, a first index that is either an index that indicates the accuracy of the geographical position or an index that is coarser than the accuracy that the index implies, and the first index Means for transmitting to the database a second indicator indicative of coarser accuracy than the accuracy;
A first list that is a list showing a first available channel available at the geographical location with the first indicator, and a first list that is available at the geographical location with the second indicator. Means for obtaining from the database a second list which is a list showing two available channels;
Means for selecting a channel to be used as a use channel from channels obtained by removing the second available channel from the first available channel;
Means for controlling the communication function unit to use the use channel. Means for storing whether the movement speed of the device is relatively slow or fast;
Means for selecting a channel to be used as a usage channel from channels obtained by removing the second available channel from the first available channel when the moving speed of the device is relatively slow;
The apparatus according to claim 1, further comprising means for selecting a channel to be used as a use channel from the second available channels when the moving speed of the own apparatus is relatively high. Communication device.   2. The communication apparatus according to claim 1, further comprising means for generating a message including at least the geographical position, the first index, and the second index as an inquiry message to the database. . Means for transmitting to the database the geographic location, the first index, the second index, and a third index indicating an accuracy coarser than the accuracy implied by the second index;
From the database, the first list, the second list, and a third list that is a list showing a third available channel available in the geographic location with the third indicator. Means to obtain,
Means for memorizing whether the movement speed of the device is relatively slow, medium or fast;
Means for selecting a channel to be used as a usage channel from channels obtained by removing the second available channel from the first available channel when the moving speed of the device is relatively slow;
Means for selecting a channel to be used as a use channel from among the channels obtained by removing the third available channel from the second available channel when the moving speed of the own device is in the middle;
The apparatus according to claim 1, further comprising means for selecting a channel to be used as a use channel from among the third available channels when the moving speed of the device is relatively high. Communication device.   The apparatus further comprises means for generating a message including at least the geographical position, the first index, the second index, and the third index as an inquiry message to the database. The communication device according to claim 4. A communication control method in a communication device having a communication function unit,
Identify the geographical location of your device,
The first index means the geographical position, a first index that is either an index that indicates the accuracy of the geographical position or an index that is coarser than the accuracy that the index implies, and the first index Send to the database a second indicator that shows a coarser accuracy than the accuracy,
A first list that is a list showing a first available channel available at the geographical location with the first indicator, and a first list that is available at the geographical location with the second indicator. A second list, which is a list showing two available channels, from the database;
A channel to be used is selected as a use channel from channels obtained by removing the second available channel from the first available channel;
A communication control method, wherein the communication function unit is controlled to use the use channel.

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