JP5391428B2 - Wireless device - Google Patents

Description

  The present invention relates to a radio apparatus.

  In IEEE802.11, two scanning methods are defined as a method for a wireless local area network (STA) to discover a wireless LAN access point (AP) (Non-patent Document 1). .

  The first scan method is a passive scan method. In this passive scan method, the STA collects beacon frames transmitted from an AP that performs wireless communication on each channel while switching communication channels, and discovers the AP and grasps the communication status.

  In this method, in order to reliably receive a beacon frame transmitted from the AP at a constant period, a beacon frame is transmitted over a beacon frame (for example, 200 milliseconds) for each channel other than the communication channel. It is necessary to wait for the reception of the frame (referred to as “scan time”).

  The second scan method is an active scan method. In this active scan method, the STA does not passively receive a beacon frame but makes a probe request to an AP that may exist in the vicinity, and actively acquires information from the AP.

  In this method, since the STA actively requests information from the AP without relying on a periodic beacon frame, the scan time of each channel can be set short (for example, 50 milliseconds).

IEEE 802.11 Standard.

  However, since the conventional scanning method is intended for discovery and connection of APs, it is premised on an operation in a state where data communication is not performed. Therefore, when the conventional scanning method is applied to channel monitoring in the AP, there is a problem that data communication that occurs at random is cut off due to a waiting time other than the communication channel or an instantaneous bandwidth shortage.

  Accordingly, the present invention has been made to solve such a problem, and an object of the present invention is to monitor a channel by a method in which a waiting time other than a communication channel or a momentary band compression is unlikely to occur. Is to provide.

  According to an embodiment of the present invention, a wireless device is a wireless device that performs wireless communication using a communication channel that is one channel arbitrarily selected from a plurality of channels, and includes a transmission unit, a reception unit, Is provided. The transmission means transmits the management frame including the address of the wireless device, the communication channel, and the congestion rate of the communication channel using all channels other than the communication channel. The receiving means receives a management frame generated in another wireless device using a communication channel. Then, the transmission means switches the communication channel to one channel other than the communication channel, transmits the management frame, and after transmitting the management frame, repeatedly returns the channel to the communication channel, thereby repeatedly executing all the channels other than the communication channel. A management frame is transmitted using the channel.

  Preferably, the transmission means transmits the management frame using one channel in a time substantially equal to the transmission time of the information frame.

  Preferably, the transmission means transmits and / or receives a data packet using a communication channel when a data packet transmission request or a data packet reception request is generated after transmission of a management frame using one channel.

  According to the embodiment of the present invention, the radio apparatus transmits a management frame including its own communication channel by switching the communication channel to one channel other than the communication channel, and after transmitting the management frame, the channel is changed to the communication channel. The management frame is transmitted using all the channels other than the communication channel by repeatedly executing the return. Also, the wireless device receives a management frame generated in another wireless device using a communication channel.

  Therefore, the wireless device can detect the communication channel of the wireless device existing in its vicinity. In addition, since the channel is returned to the communication channel after the management frame is transmitted, it is difficult to generate a waiting time other than the communication channel. Furthermore, compared to the active scan method in which responses are transmitted simultaneously from other wireless devices each time a probe request is made, the scan method according to the embodiment of the present invention requires no response and the management frame is temporally Even when there are many access points in the vicinity without concentration, it is possible to make it difficult to generate an instantaneous band tightness.

It is a block diagram of the radio | wireless apparatus by embodiment of this invention. It is a flowchart for demonstrating the transmission method of a management frame. It is a conceptual diagram of transmission / reception of the management frame between several radio | wireless apparatuses.

  Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  FIG. 1 is a configuration diagram of a radio apparatus according to an embodiment of the present invention. Referring to FIG. 1, radio apparatus 10 according to an embodiment of the present invention includes antenna 1, channel selection means 2, reception means 3, transmission means 4, communication management means 5, and timer 6. . The wireless device 10 is an access point.

  The channel selection means 2 selects a plurality of channels Ch1 to Chn (n is an integer of 2 or more) from a communication band that can be used as a radio resource. The channel selection unit 2 receives a management frame from the reception unit 3 and detects a communication channel used by another wireless device (= access point) for transmission / reception of a data packet from the received management frame.

  Then, the channel selection unit 2 selects a communication channel Ch_cm used by the wireless device 10 for transmission / reception of data packets from the plurality of channels Ch1 to Chn, excluding communication channels used in other wireless devices.

  Then, the channel selection unit 2 outputs the selected communication channel Ch_cm to the reception unit 3, and outputs a plurality of channels Ch1 to Chn and the communication channel Ch_cm to the transmission unit 4.

  The receiving unit 3 receives the communication channel Ch_cm from the channel selecting unit 2. And the receiving means 3 receives a packet from another radio | wireless apparatus via the antenna 1 by communication channel Ch_cm.

  The receiving means 3 outputs the received packet to the channel selecting means 2 when the received packet is a management frame. Further, the channel selection means 2 outputs the received packet to the communication management means 5 when the received packet is a data packet.

  The transmission unit 4 receives a plurality of channels Ch1 to Chn and a communication channel Ch_cm from the channel selection unit 2. Further, the transmission means 4 receives the congestion rate BSY and data packet of the communication channel Ch_cm from the communication management means 5.

  The congestion ratio BSY is expressed as a ratio of a time during which the communication channel Ch_cm is used with respect to a certain time.

  When the transmission unit 4 receives the congestion rate BSY from the communication management unit 5, the transmission unit 4 generates a management frame CTLF = [Add10 / Ch_cm / BSY] including the address Add10, the communication channel Ch_cm, and the congestion rate BSY of the wireless device 10.

  The transmission means 4 selects one channel Ch_other1 other than the communication channel Ch_cm from the plurality of channels Ch1 to Chn every time the timer 6 measures the fixed period T (T = 5 to 10 seconds), and the channel Is switched from the communication channel Ch_cm to the channel Ch_other1 and the management frame CTLF is broadcast via the antenna 1. In this case, the transmission unit 4 transmits the management frame CTLF in a time of 1 millisecond or less, for example.

  Thereafter, the transmission means 4 returns the channel from the channel Ch_other1 to the communication channel Ch_cm.

  Then, the transmission means 4 waits for t (milliseconds), selects one channel Ch_other2 (≠ Ch_other1) other than the communication channel Ch_cm from the plurality of channels Ch1 to Chn, and selects the channel from the communication channel Ch_cm to the channel Ch_other2 And the management frame CTLF is broadcast via the antenna 1.

  Thereafter, the transmission means 4 returns the channel from the channel Ch_other2 to the communication channel Ch_cm.

  Thereafter, the transmission unit 4 repeatedly transmits the management frame CTLF by the above-described method until transmission of the management frame CTLF using all channels other than the communication channel Ch_cm is completed.

  Then, when the transmission of the management frame CTLF using all channels other than the communication channel Ch_cm is completed, the transmission unit 4 refers to the timer 6 to determine whether or not the fixed period T has elapsed, and the fixed period T is After the elapse of time, the management frame CTLF is transmitted again using all channels other than the communication channel Ch_cm.

  The transmission unit 4 transmits a data packet using the communication channel Ch_cm when receiving a data packet from the communication management unit 5 during transmission of the management frame CTLF using all channels other than the communication channel Ch_cm.

  The communication management unit 5 generates a data packet and outputs the generated data packet to the transmission unit 4. The communication management means 5 refers to the timer 6 and outputs the data packet to the transmission means 4 and then the time until the data packet transmitted from the terminal device is received from the reception means 3 is the usage time of the communication channel Ch_cm. Measure as Then, the communication management means 5 calculates the ratio of the usage time of the communication channel Ch_cm with respect to a certain time as the congestion ratio BSY, and outputs the calculated congestion ratio BSY to the transmission means 4.

  The timer 6 measures time in response to a request from the transmission unit 4 or the communication management unit 5.

  FIG. 2 is a flowchart for explaining a management frame transmission method. Referring to FIG. 2, when the transmission of the management frame is started, the transmission unit 4 of the wireless device 10 determines whether or not the monitoring timer has timed out by determining whether or not the timer 6 measures the fixed period T. It is determined whether or not (step S1).

  When the monitoring timer times out, the transmission unit 4 shifts the channel to an unscanned channel (step S2).

  Then, the transmission means 4 transmits (broadcasts) the management frame CTLF using the channel after the transition (step S3).

  Thereafter, the transmission unit 4 adds the channel used for transmission of the management frame CTLF to the scanned channel list (built in the transmission unit 4) (step S4).

  Subsequently, the transmission unit 4 shifts the channel to the communication channel Ch_cm (step S5), and determines whether all the channels have been scanned (step S6).

  When it is determined in step S6 that all channels have not been scanned, the transmission unit 4 refers to the timer 6 and waits for time t (step S7).

  Then, the transmission means 4 determines whether transmission data to the terminal device or reception data from the terminal device has occurred during standby (step S8).

  When it is determined in step S8 that transmission data or reception data has occurred during standby, the series of operations proceeds to step S7.

  On the other hand, when it is determined in step S8 that no transmission data or reception data has been generated during standby, the series of operations proceeds to step S2.

  On the other hand, when it is determined in step S6 that all channels have been scanned, the transmission unit 4 resets the scanned channel list and sets a monitoring timer (= timer 6) (step S9). As a result, a series of operations is completed.

  In this way, the wireless device 10 broadcasts the management frame CTLF including the communication channel Ch_cm using all the channels other than the communication channel Ch_cm while returning the channel to the communication channel Ch_cm one by one.

  FIG. 3 is a conceptual diagram of transmission / reception of a management frame CTLF between a plurality of wireless devices. Referring to FIG. 3, each of wireless devices A to E has the same configuration as wireless device 10. Further, the wireless devices A to E perform wireless communication using the channels CH44, CH36, CH40, CH48, and CH52 as communication channels CH_cm, respectively.

  Then, the wireless device A scans channels CH36, CH40, CH48, and CH52 other than its own communication channel CH44 and broadcasts a management frame CTLF including its own communication channel CH44.

  Also, the wireless device B scans channels CH40, CH44, CH48, and CH52 other than its own communication channel CH36 and broadcasts a management frame CTLF including its own communication channel CH36.

  Furthermore, the radio apparatus C scans channels CH36, CH44, CH48, and CH52 other than its own communication channel CH40 and broadcasts a management frame CTLF including its own communication channel CH40.

  Further, the wireless device D scans channels CH36, CH40, CH44, and CH52 other than its own communication channel CH48 and broadcasts a management frame CTLF including its own communication channel CH48.

  Furthermore, the wireless device E scans channels CH36, CH40, CH44, and CH48 other than its own communication channel CH52 and broadcasts a management frame CTLF including its own communication channel CH52.

  Then, the wireless devices B to E receive the management frame CTLF transmitted from the wireless device A through their own communication channels CH36, CH40, CH48, and CH50, and detect the communication channel CH44 of the wireless device A.

  Further, the wireless devices A, C to E receive the management frame CTLF transmitted from the wireless device B through their own communication channels CH44, CH40, CH48, and CH52, and detect the communication channel CH36 of the wireless device B.

  Further, the wireless devices A, B, D, and E receive the management frame CTLF transmitted from the wireless device C through their own communication channels CH44, CH36, CH48, and CH52, respectively, and detect the communication channel CH40 of the wireless device C. To do.

  Further, the wireless devices A to C and E receive the management frame CTLF transmitted from the wireless device D through their own communication channels CH44, CH36, CH40, and CH52, and detect the communication channel CH48 of the wireless device D.

  Further, each of the wireless devices A to D receives the management frame CTLF transmitted from the wireless device E through its own communication channels CH44, CH36, CH40, and CH48, and detects the communication channel CH52 of the wireless device E.

  As a result, each of the wireless devices A to E can detect the communication channel Ch_cm of the wireless device existing around the wireless device.

  Each of the wireless devices A to E transmits the management frame CTLF in a time equal to the transmission time of the data packet, that is, in many cases, a time of 1 millisecond or less. Therefore, the scanning time can be greatly shortened compared with the conventional scanning method. As a result, even when data communication suddenly occurs in the direction from the subordinate terminal device to the wireless devices A to E (= access point) during the channel scan, the data communication disconnection time can be reduced.

  Furthermore, compared to the active scan method in which responses are transmitted simultaneously from other APs every time a probe request is made, the scan method according to the embodiment of the present invention does not require a response and the management frame is concentrated in time. Even when there are a lot of access points in the vicinity, it is possible to prevent instantaneous band tightness.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

  The present invention is applied to a wireless device.

  1 antenna, 2 channel selection means, 3 reception means, 4 transmission means, 5 communication management means, 6 timer, 10 radio apparatus.

Claims (3)

A wireless device that performs wireless communication using a communication channel that is one channel arbitrarily selected from a plurality of channels,
Transmitting means for transmitting a management frame including an address of the wireless device, the communication channel, and a congestion rate of the communication channel using all channels other than the communication channel;
Receiving means for receiving the management frame generated in another wireless device using the communication channel;
The transmission means switches the communication channel to one channel other than the communication channel, transmits the management frame, and after transmitting the management frame, repeatedly returns the channel to the communication channel, thereby performing the communication. A wireless device that transmits the management frame using all channels other than the channel.   The radio apparatus according to claim 1, wherein the transmission unit transmits the management frame using the one channel in a time substantially equal to a transmission time of an information frame.   The transmission means transmits and / or receives the data packet using the communication channel when a transmission request for a data packet or a reception request for the data packet occurs after transmission of the management frame using the one channel. The wireless device according to claim 1 or 2.

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