JP2005236435A - Radio communication method, radio communication apparatus and radio ad hoc network system - Google Patents

Radio communication method, radio communication apparatus and radio ad hoc network system Download PDF

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JP2005236435A
JP2005236435A JP2004040481A JP2004040481A JP2005236435A JP 2005236435 A JP2005236435 A JP 2005236435A JP 2004040481 A JP2004040481 A JP 2004040481A JP 2004040481 A JP2004040481 A JP 2004040481A JP 2005236435 A JP2005236435 A JP 2005236435A
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terminal
packet
step
transmission request
radio
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Atsushi Fujiwara
Akira Yamada
曉 山田
藤原  淳
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Ntt Docomo Inc
株式会社エヌ・ティ・ティ・ドコモ
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<P>PROBLEM TO BE SOLVED: To provide a radio communication method, a radio communication apparatus and a radio ad hoc network system capable of preventing loss of a communication opportunity and deterioration in network performance due to a hidden terminal problem in a radio LAN. <P>SOLUTION: In the radio communication method for allocating radio bands by a virtual carrier sense, the radio band is preferentially allocated to a terminal re-transmitting a transmission request. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a wireless communication method, a wireless communication apparatus, and a wireless ad hoc network system.

  A wireless ad hoc network system refers to a wireless terminal in which each of a plurality of wireless terminals can communicate with each other within a predetermined range without requiring a centralized control station represented by a base station in a mobile phone. This is a technology that enables data communication to a distant place by performing data communication, and a wireless terminal on the way from a transmission-source wireless terminal to a transmission-destination wireless terminal relays data.

  FIG. 1 is a diagram illustrating a configuration example of a general wireless ad hoc network system. In FIG. 1, when it is assumed that the data communication can be performed only between adjacent terminals, between terminals within the mutual communication range (between terminal 11 and terminal 12, between terminal 12 and terminal 13, terminal 13 and terminal 14), data communication is performed directly, and between terminals that cannot communicate directly (between terminal 11 and terminal 14, between terminal 11 and terminal 13, and between terminal 12 and terminal 14) via a terminal in the middle Data communication is performed indirectly.

  By the way, in the wireless ad hoc network system using wireless LAN, there exists a problem that network performance falls by the collision of the packet resulting from a hidden terminal problem (for example, refer nonpatent literature 1). FIG. 2 is a diagram showing how the hidden terminal problem occurs, but a terminal 13 that can receive a radio wave of a terminal 12 adjacent to a certain terminal 11 but cannot be directly communicated because it is located farther than that. Occurs when communication is possible between the terminal 12 and the terminal 13. In such a case, when the terminal 11 and the terminal 13 try to transmit data to the same terminal 12, respectively, the terminal 11 and the terminal 13 cannot determine each other's signal, and thus determine that transmission is possible. At the same time, the packet may be transmitted. As a result, a packet collision occurs in the terminal 12, and data cannot be received.

  In order to solve this problem, IEEE 802.11, which is a wireless LAN standard, defines a mechanism called virtual carrier sense (see, for example, Non-Patent Document 2). This is done by sending an RTS (Request To Send) packet informing that the data is to be transmitted prior to the data transmission to the destination terminal and returning a CTS (Clear To Send) packet permitting the data transmission. , A right to use a radio band called NAV (Network Allocation Vector) is given to a terminal that has transmitted an RTS packet. Note that the RTS packet includes information on the time to use the radio band required until an ACK (ACKnowledgement) packet indicating reception confirmation is returned from the data transmission destination. Based on this information, the RTS packet Other terminals within the receivable range are suppressed from transmitting data, and packet collision can be prevented. Also, the CTS packet includes information on the time during which the terminal that transmitted the RTS packet uses the radio band, and other terminals in the CTS packet receivable range are suppressed from transmitting data.

FIG. 3 is a sequence diagram illustrating an operation of radio band allocation by virtual carrier sense. When an RTS packet is transmitted from the terminal 11 to the terminal 12 (step S11), a CTS packet is transmitted from the terminal 12 to the terminal 11. Returned (step S12), the terminal 11 transmits data to the terminal 12 (step S14). Note that the CTS packet transmitted from the terminal 12 also reaches the adjacent terminal 13 (step S13), and since the terminal 13 is not a packet addressed to itself, the data transmission is stopped by the restriction based on the NAV and is in a standby state. to go into. Then, when data transmission from the terminal 11 to the terminal 12 is completed, an ACK packet is transmitted from the terminal 12 to the terminal 11 (step S15), and this ACK packet also reaches the terminal 13 (step S16). The NAV given to the terminal 11 is canceled by the transmission of this ACK packet, and at the same time, the terminal 13 is released from the transmission stop standby state. By these operations, the terminal 11 and the terminal 13 do not transmit data to the terminal 12 at the same time, and packet collision can be prevented.
Kazuo Hasuike, Sonprakash, Bandiopadai, Tetsuro Ueda: "Technical Issues of Ad Hoc Networks", IEICE Transactions B, Vol.J85-B N12 pp.2007-2014, December 2002 ANSI / IEEE std 802.11, Wireless LAN medium access control (MAC) and physical layer (PHY) specifications, 1999.

  The virtual carrier sense in the conventional wireless LAN is performed as described above, and the typical hidden terminal problem as shown in FIG. 2 is solved, but the hidden terminal problem is still completely solved. There was a problem that it could not be solved. The state of the occurrence is shown in FIGS.

  4 and 5, the terminals 11 to 14 are arranged so that data communication can be performed only between adjacent terminals in the same manner as shown in FIG. 1, and from the terminal 11 to the terminal 12 and from the terminal 14 It is assumed that data transmission to the terminal 13 is being performed. In the figure, R indicates an RTS packet, C indicates a CTS packet, and A indicates an ACK packet.

  In FIG. 4, when the terminal 11 transmits an RTS packet to the terminal 12 (step S21), the terminal 12 returns a CTS packet to the terminal 11 (step S22), and at the same time enters a standby state by NAV based on the RTS packet from the terminal 11. Enter (step S23). Thereafter, the terminal 11 transmits data to the terminal 12 (step S24), and the terminal 12 transmits an ACK packet to the terminal 11 when the reception of the data is completed (step S25).

  On the other hand, since the CTS packet (step S22) transmitted from the terminal 12 reaches the adjacent terminal 13, the terminal 13 is in a standby state by NAV based on the CTS packet from the terminal 12 (step S26). After that, when the terminal 14 tries to transmit the RTS packet to the terminal 13, the terminal 14 does not know that the terminal 13 is in the standby state by the NAV, so the RTS packet is repeatedly transmitted. (Steps S27 and S28).

  Similarly, while the next data communication is being performed between the terminal 11 and the terminal 12 (steps S29 to S33), the terminal 13 similarly enters a standby state by NAV (step S34). RTS packets from are not accepted (step S35). In addition, if the terminal 14 can know the time when the data communication between the terminal 11 and the terminal 12 is completed, the RTS packet can be transmitted from the terminal 14 to the terminal 13 at an appropriate timing. Thus, since the terminal 14 does not know that the terminal 13 is in the standby state by NAV, there is a high possibility that the retransmission of such a useless RTS packet is repeated, and unless the standby state by the NAV of the terminal 13 is canceled, Unable to get communication opportunities.

  Next, in FIG. 5, the CTS packet (step S42) returned from the terminal 12 collides with the RTS packet (step S43) transmitted from the terminal 14 with respect to the RTS packet (step S41) transmitted from the terminal 11. The case where S44) is caused is shown. In this case, since the terminal 13 does not enter the NAV standby state due to the CTS packet transmitted from the terminal 12 (step S42), the terminal 13 responds to the subsequent RTS packet (step S46) retransmitted from the terminal 14. (Step S47), which collides with the data transmission (step S45) performed from the terminal 11 to the terminal 12 (step S48).

  Further, the terminal 14 performs data transmission by the CTS packet (step S47) transmitted from the terminal 13 to the terminal 14 (step S50), and when the completion is completed, the terminal 13 returns an ACK packet to the terminal 14 (step S51). A CTS packet (step S55) returned from the terminal 13 in response to an RTS packet (step S54) from the terminal 14 will also collide with a retransmission of the data of the terminal 11 (step S49) (step S52). It will also collide (step S56) with the retransmission of the data of the terminal 11 (step S53). As described above, since the terminal 11 repeats the retransmission of the data packet, the network performance is greatly deteriorated.

  The present invention has been proposed in view of the above-described conventional problems, and an object of the present invention is to provide a wireless communication method and wireless communication capable of preventing loss of communication opportunities and deterioration of network performance due to a hidden terminal problem. It is to provide a device and a wireless ad hoc network system.

  In order to solve the above-mentioned problem, in the present invention, as described in claim 1, in a wireless communication method for allocating a wireless band by virtual carrier sense, priority is given to a terminal that retransmits a transmission request. The wireless band is assigned to the system. As a result, a radio band is preferentially assigned to a terminal that retransmits a transmission request, and loss of a communication opportunity can be prevented.

  In addition, as described in claim 2, it is possible to notify the terminal that retransmits the transmission request after the release of its standby state. Thus, the terminal that has received the bandwidth allocation notification can start data transmission.

  According to a third aspect of the present invention, a transmission request can be made from a terminal that retransmits the transmission request in response to the band allocation notification, and data transmission can be performed after a transmission permission is returned. . As a result, the standard virtual carrier sense procedure is followed, and inconveniences can be eliminated even if there are terminals that are not compatible with this method.

  In addition, as described in claim 4, a terminal other than the terminal that retransmits the transmission request and that has received the bandwidth allocation notification as a standby notification is different from other terminals in the communicable range. It is possible to perform a standby notification. As a result, it is possible to widely notify the terminal that retransmits the transmission request that the radio band is allocated, and it is possible to prevent a useless transmission request from being performed.

  In addition, as described in claim 5, after transmitting the band allocation notification, radio band allocation is performed to a terminal that retransmits the transmission request after a predetermined time after transmission of the other standby notification is completed. can do. Thus, the terminal that has received the bandwidth allocation notification can start data transmission after a certain time.

  According to a sixth aspect of the present invention, a transmission request can be made from a terminal that retransmits the transmission request after the predetermined time, and data transmission can be performed after a transmission permission is returned. As a result, the standard virtual carrier sense procedure is followed, and inconveniences can be eliminated even if there are terminals that are not compatible with this method.

  Further, as described in claim 7, it is possible to prevent the transmission permission from being returned in response to the retransmission of the transmission request. Thereby, it is possible to prevent a decrease in network performance due to packet collision.

  According to another aspect of the present invention, in the wireless communication apparatus that assigns a radio band by virtual carrier sense, a radio having a function of preferentially assigning a radio band to a terminal that retransmits a transmission request. It can also be configured as a communication device.

  In addition, as described in claim 9, a plurality of wireless communication devices having a function of allocating a wireless band by virtual carrier sense and preferentially allocating a wireless band to a terminal that retransmits a transmission request It can also be configured as a wireless ad hoc network system configured by.

  In the present invention, it is possible to prevent loss of communication opportunities and network performance degradation due to the hidden terminal problem.

  Preferred embodiments of the present invention will be described below with reference to the drawings.

  FIG. 6 is a diagram showing a configuration example of a wireless ad hoc network system according to an embodiment of the present invention. In FIG. 6, terminals 1 to 4 are arranged so that data communication can be performed only between adjacent terminals, and data is transmitted from terminal 1 to terminal 2 and from terminal 4 to terminal 3. And

  In FIG. 6, the RTS packet and the CTS packet are exchanged between the terminal 1 and the terminal 2, the data transmission from the terminal 1 to the terminal 2 is performed (step S1), and the standby notification from the terminal 2 by the CTS packet ( In a state where step S2) is given to the terminal 3 and the terminal 3 is in a standby state by NAV, when the terminal 3 detects that a transmission request is retransmitted from the terminal 4 (step S3), the terminal 3 In order to preferentially allocate the radio band, the function of transmitting an ITS (Invite To Send) packet that is a band allocation notification to the terminal 4 after the standby state is released (step S4) is provided. Yes. This ITS packet is a packet newly defined in the present invention. Further, the ITS packet (step S4) transmitted from the terminal 3 to the terminal 4 acts as a standby notification (step S5) to the adjacent terminal 2 in the communicable range of the terminal 3. Furthermore, in order to prevent the network performance from being degraded due to packet collision, the terminal 3 improves the normal virtual carrier sense operation, and the transmission request CTS packet is added to the RTS packet of the transmission request retransmitted from the terminal 4. A function of not returning can be provided.

  On the other hand, as an expanded form of the present invention, the terminal 2 that has received the standby notification (step S5) from the terminal 3 notifies the terminal 4 widely that the radio band is allocated, and therefore is adjacent to the communicable range. The terminal 1 further has a function of transmitting a CCTS (Copied Clear To Send) packet as a standby notification (step S6). This CCTS packet is also a packet newly defined in the present invention.

  Although the above function has been described on the assumption that data transmission is performed between specific terminals, since data communication is performed between arbitrary terminals depending on the arrangement of terminals, each terminal has the above functions in common. It is what.

  7 to 11 are sequence diagrams showing the operation of the embodiment of the present invention shown in FIG. 6, and terminals 1 to 4 can perform data communication only between adjacent terminals as shown in FIG. It is assumed that data is transmitted from the terminal 1 to the terminal 2 and from the terminal 4 to the terminal 3.

  In FIG. 7, when the terminal 1 transmits an RTS packet to the terminal 2 (step S101), the terminal 2 returns a CTS packet to the terminal 1 (step S102), and at the same time enters a standby state by NAV based on the RTS packet from the terminal 1. Enter (step S103). Thereafter, terminal 1 transmits data to terminal 2 (step S104), and terminal 2 transmits an ACK packet to terminal 1 upon completion of data reception (step S105).

  On the other hand, since the CTS packet (step S102) transmitted from the terminal 2 reaches the adjacent terminal 3, the terminal 3 is in a standby state by NAV based on the CTS packet from the terminal 2 (step S106). Thereafter, when the terminal 4 tries to transmit the RTS packet to the terminal 3, the terminal 4 does not know that the terminal 3 is in the standby state by the NAV at this time, and therefore repeatedly transmits the RTS packet. Will not be accepted (steps S107 and S108).

  When the terminal 3 detects that the RTS packet is retransmitted from the terminal 4 (step S108), the terminal 3 transmits an ACK packet (step S105) or is included in the CTS packet (step S102) received from the terminal 2. After the standby state (step S106) is canceled due to the elapse of the standby time, an ITS packet (indicated by “I” in the figure) for notifying the band allocation is transmitted to the terminal 4 (step S109). The terminal 3 can detect that the RTS packet has been continuously received from the terminal 4 or that the RTS packet has been retransmitted by a retransmission flag in the RTS packet. You can know that you have data to do. Then, by receiving the ITS packet (step S109) from the terminal 3, the terminal 4 can know that the terminal 3 has been in a standby state by NAV until then, and can start data transmission (step S110). ). Thereafter, when the reception of data is completed, the terminal 3 transmits an ACK packet to the terminal 4 (step S111).

  On the other hand, the ITS packet (step S109) transmitted from the terminal 3 reaches the adjacent terminal 2, the terminal 2 enters a standby state by the NAV (step S112), and an ACK packet is transmitted from the terminal 3 (step S111). ) Or when the time until the communication between the terminal 3 and the terminal 4 included in the ITS packet (step S109) is completed is canceled. Therefore, even if terminal 1 transmits an RTS packet to terminal 2 during that time, it is not accepted (steps S113 and S114). Note that the ITS packet (step S109) can include information indicating the time until the communication between the terminal 3 and the terminal 4 is completed. The terminal can be notified in advance.

  With the above operation, a radio band is preferentially allocated to the terminal 4 that has retransmitted the RTS packet that is a transmission request, and loss of the communication opportunity of the terminal 4 can be prevented.

  Next, FIG. 8 shows an operation example in which the CTS packet is not returned from the terminal 3 to the RTS packet retransmitted from the terminal 4, thereby preventing a decrease in network performance due to packet collision. is there.

  In FIG. 8, the CTS packet (step S202) sent back from the terminal 2 collides with the RTS packet (step S206) sent from the terminal 4 with respect to the RTS packet sent from the terminal 1 (step S201). When it happens, the terminal 3 does not enter the standby state by NAV, but the terminal 3 does not return the CTS packet to the RTS packet retransmitted from the terminal 4 (step S208) (step S209). The terminal 4 does not start data transmission to the terminal 3. Therefore, the data transmission (step S204) performed from the terminal 1 to the terminal 2 does not collide with the CTS packet that would have been transmitted from the terminal 3, and the normal operation (steps S210 to S217) is performed thereafter. Can be expected. Thereby, since the terminal 1 does not repeat the retransmission of the data packet, it is possible to prevent the network performance from being deteriorated.

  Next, in FIG. 9, the terminal 2 that has received the ITS packet transmitted from the terminal 3 as a standby notification further transmits a standby notification as a CCTS packet to the terminal 1 in the communicable range, thereby allowing the terminal 4 to This is to widely notify that the allocation is performed, and to prevent a useless transmission request from the terminal 1 from being performed.

  In FIG. 9, when the terminal 1 transmits an RTS packet to the terminal 2 (step S301), the terminal 2 returns a CTS packet to the terminal 1 (step S302), and at the same time enters a standby state by NAV based on the RTS packet from the terminal 1. Enter (step S303). Thereafter, terminal 1 transmits data to terminal 2 (step S304), and terminal 2 transmits an ACK packet to terminal 1 when data reception is completed (step S305).

  On the other hand, since the CTS packet (step S302) transmitted from the terminal 2 reaches the adjacent terminal 3, the terminal 3 is in a standby state by NAV based on the CTS packet from the terminal 2 (step S306). Thereafter, when the terminal 4 tries to transmit the RTS packet to the terminal 3, the terminal 4 does not know that the terminal 3 is in the standby state by the NAV at this time, and therefore repeatedly transmits the RTS packet. Is not accepted (steps S307 and S308).

  When the terminal 3 detects that the RTS packet has been retransmitted from the terminal 4 (step S308), the terminal 3 transmits an ACK packet (step S305) or is included in the CTS packet (step S302) received from the terminal 2. After the standby state is canceled due to the elapse of the standby time (step S306), an ITS packet for performing bandwidth allocation to the terminal 4 is transmitted to the terminal 2 (step S309). The terminal 2 receiving the ITS packet enters a standby state by NAV (step S310) and transmits a CCTS packet indicated by “CC” in the figure to the terminal 1 (step S311). As a result, the terminal 1 enters a standby state by NAV (step S312), and thereafter no unnecessary transmission request is made until the standby state is canceled.

  On the other hand, the terminal 4 that has received the ITS packet (step S309) from the terminal 3 is assumed to actually perform the radio band allocation after a certain time after the transmission of the CCTS packet (step S311) from the terminal 2 to the terminal 1 is completed. Data transmission is started (step S313). After that, the terminal 3 transmits an ACK packet when the reception of data is completed (step S314), and the standby state (step S310) by the NAV of the terminal 2 is determined by the ACK packet or included in the ITS packet (step S309). -It is canceled when the time until the communication between the terminals 4 is completed has elapsed.

  Next, FIG. 10 is a slight improvement on the operation of FIG. 7, and instead of starting data transmission from the terminal 4 in response to the ITS packet transmitted from the terminal 3, the basic operation of the virtual carrier sense is temporarily performed. By transmitting data after exchanging RTS packets and CTS packets based on the system, inconvenience does not occur even if there are terminals that do not support the ITS packet of the present invention. Is. That is, when there are terminals that do not support the ITS packet around the terminal 4, the ITS packet cannot enter the standby state by the NAV, but the terminal 4 does not receive the RTS packet and the CTS packet of the general virtual carrier sense. By performing the exchange, it is possible to reliably enter the standby state by NAV.

  In FIG. 10, when terminal 1 transmits an RTS packet to terminal 2 (step S401), terminal 2 returns a CTS packet to terminal 1 (step S402), and at the same time, enters a standby state by NAV based on the RTS packet from terminal 1. Enter (step S403). Thereafter, terminal 1 transmits data to terminal 2 (step S404), and terminal 2 transmits an ACK packet to terminal 1 upon completion of data reception (step S405).

  On the other hand, since the CTS packet (step S402) transmitted from the terminal 2 reaches the adjacent terminal 3, the terminal 3 is in a standby state by NAV based on the CTS packet from the terminal 2 (step S406). Thereafter, when the terminal 4 tries to transmit the RTS packet to the terminal 3, the terminal 4 does not know that the terminal 3 is in the standby state by the NAV at this time, and therefore repeatedly transmits the RTS packet. Will not be accepted (steps S407, S408).

  When the terminal 3 detects that the RTS packet has been retransmitted from the terminal 4 (step S408), the terminal 3 transmits an ACK packet (step S405) or is included in the CTS packet (step S402) received from the terminal 2. After the standby state is canceled due to the elapse of the standby time (step S406), an ITS packet for notifying the terminal 4 of bandwidth allocation is transmitted (step S409). Then, the terminal 4 that has received the ITS packet from the terminal 3 transmits an RTS packet to the terminal 3 in accordance with a general virtual carrier sense procedure (step S410), and waits for reception of the CTS packet from the terminal 3 (step S410). S411), data transmission is started (step S412). After that, when the reception of data is completed, the terminal 3 transmits an ACK packet to the terminal 4 (step S413). On the other hand, the ITS packet (step S409) transmitted from the terminal 3 reaches the adjacent terminal 2, and the terminal 2 enters a standby state by the NAV (step S414), and an ACK packet is transmitted from the terminal 3 (step S413). ) Is released. Therefore, even if the terminal 1 transmits an RTS packet to the terminal 2 during that time, it is not accepted (steps S415 and S416). In this example, the ITS packet (step S409) transmitted from the terminal 3 does not need to include information indicating the standby state time according to the data communication time between the terminal 3 and the terminal 4. This is because the RTS packet and the CTS packet are exchanged in accordance with a general virtual carrier sense procedure in response to the ITS packet, and information indicating the standby state time is included in the packet.

  Next, FIG. 11 is a slight improvement of the operation of FIG. 9, and instead of starting data transmission from the terminal 4 after a certain time after the transmission of the CCTS packet from the terminal 2 is completed, the basic of virtual carrier sense is once performed. By transmitting data after exchanging RTS packets and CTS packets based on the operation, no inconvenience occurs even when there are terminals that do not support the ITS packet of the present invention. It is a thing.

  In FIG. 11, when the terminal 1 transmits an RTS packet to the terminal 2 (step S501), the terminal 2 returns a CTS packet to the terminal 1 (step S502), and at the same time enters a standby state by NAV based on the RTS packet from the terminal 1. Enter (step S503). Thereafter, the terminal 1 transmits data to the terminal 2 (step S504), and the terminal 2 transmits an ACK packet to the terminal 1 when the reception of the data is completed (step S505).

  On the other hand, since the CTS packet (step S502) transmitted from the terminal 2 reaches the adjacent terminal 3, the terminal 3 is in a standby state by NAV based on the CTS packet from the terminal 2 (step S506). Thereafter, when the terminal 4 tries to transmit the RTS packet to the terminal 3, the terminal 4 does not know that the terminal 3 is in the standby state by the NAV at this time, and therefore repeatedly transmits the RTS packet. Is not accepted (steps S507 and S508).

  When terminal 3 detects that the RTS packet has been retransmitted from terminal 4 (step S508), ACK packet is transmitted from terminal 2 (step S505) or included in the CTS packet received from terminal 2 (step S502). After the standby state (step S506) is canceled due to the elapse of the standby time, an ITS packet indicating bandwidth allocation to the terminal 4 is transmitted to the terminal 2 (step S509). The terminal 2 that has received the ITS packet enters a standby state by NAV (step S510) and transmits a CCTS packet to the terminal 1 (step S511). As a result, the terminal 1 enters a standby state by NAV (step S512), and thereafter no unnecessary transmission request is made until the standby state is canceled.

  On the other hand, the terminal 4 that has received the ITS packet (step S509) from the terminal 3 transmits the RTS packet according to a general virtual carrier sense procedure after a certain time after the transmission of the CCTS packet (step S511) from the terminal 2 to the terminal 1 is completed. It transmits to the terminal 3 (step S513), waits for the reception of the CTS packet from the terminal 3 (step S514), and starts data transmission (step S515). Thereafter, when the reception of data is completed, the terminal 3 transmits an ACK packet (step S516), and the standby state by the NAV of the terminal 2 (step S510) is cancelled.

  Note that the above-described operation modes can be used alone or switched. When the operation mode is switched and used, the operation mode can be switched by periodically transmitting beacon packets in the wireless ad hoc network system. That is, by setting a flag indicating that an ITS packet or a CCTS packet can be used in a beacon packet, it is possible to perform a MAC (Medium Access Control) process corresponding to a participating ad hoc network.

  Further, the above-described method is easy to apply because it does not significantly change the protocol used in the current wireless LAN.

  As a result, the performance of the wireless ad hoc network system can be improved as a result of the above-described method. Therefore, voice communication using an IP (Internet Protocol) network technology expected to be used as an application in an ad hoc network (VOIP: Voice over IP) and TCP-based communication systems, etc. can be improved.

  The present invention has been described above by the preferred embodiments of the present invention. While the invention has been described with reference to specific embodiments, various modifications and changes may be made to the embodiments without departing from the broad spirit and scope of the invention as defined in the claims. Obviously you can. In other words, the present invention should not be construed as being limited by the details of the specific examples and the accompanying drawings.

1 is a diagram illustrating a configuration example of a wireless ad hoc network system. It is a figure which shows the mode of generation | occurrence | production of a hidden terminal problem. It is a sequence diagram which shows the operation | movement of the radio | wireless band allocation by virtual carrier sense. It is FIG. (1) which shows the mode of the occurrence of the hidden terminal problem which cannot be solved by virtual carrier sense. It is FIG. (2) which shows the mode of the occurrence of the hidden terminal problem which cannot be solved by virtual carrier sense. It is a figure which shows the structural example of the radio | wireless ad hoc network system concerning one Embodiment of this invention. It is a sequence diagram (the 1) which shows operation | movement of one Embodiment of this invention. It is a sequence diagram (the 2) which shows operation | movement of one Embodiment of this invention. It is a sequence diagram (the 3) which shows operation | movement of one Embodiment of this invention. It is a sequence diagram (the 4) which shows operation | movement of one Embodiment of this invention. It is a sequence diagram (the 5) which shows operation | movement of one Embodiment of this invention.

Explanation of symbols

1-4 Terminal R RTS (Request To Send) packet C CTS (Clear To Send) packet A ACK (ACKnowledgement) packet I ITS (Invite To Send) packet CC CCTS (Copied Clear To Send) packet

Claims (9)

  1. In a wireless communication method for assigning a wireless band by virtual carrier sense,
    A radio communication method characterized by preferentially allocating a radio band to a terminal that retransmits a transmission request.
  2.   The wireless communication method according to claim 1, wherein a bandwidth allocation notification is made to a terminal that retransmits the transmission request after its own standby state is released.
  3.   3. The wireless communication method according to claim 2, wherein a transmission request is made from a terminal that retransmits the transmission request in response to the bandwidth allocation notification, and data transmission is performed after a transmission permission return.
  4.   The terminal other than the terminal that retransmits the transmission request, wherein the terminal that has received the bandwidth allocation notification as a standby notification sends another standby notification to another terminal within a communicable range. The wireless communication method according to any one of 2 and 3.
  5.   5. The wireless communication method according to claim 4, wherein after transmitting the bandwidth allocation notification, a wireless bandwidth is allocated to a terminal that retransmits the transmission request after a predetermined time when transmission of the other standby notification is completed. .
  6.   6. The wireless communication method according to claim 5, wherein a transmission request is made from a terminal that retransmits the transmission request after the predetermined time, and data transmission is performed after a transmission permission is returned.
  7.   The wireless communication method according to any one of claims 1 to 6, wherein a transmission permission is not returned in response to retransmission of a transmission request.
  8. In a wireless communication device that assigns a wireless band by virtual carrier sense,
    A radio communication apparatus comprising a function of preferentially allocating a radio band to a terminal that retransmits a transmission request.
  9.   A wireless ad hoc network comprising a plurality of wireless communication devices having a function of allocating a wireless band by virtual carrier sense and preferentially allocating a wireless band to a terminal that retransmits a transmission request system.
JP2004040481A 2004-02-17 2004-02-17 Radio communication method, radio communication apparatus and radio ad hoc network system Pending JP2005236435A (en)

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010500828A (en) * 2006-08-07 2010-01-07 クゥアルコム・インコーポレイテッドQualcomm Incorporated Monitoring period for asynchronous wireless communication
JP2010081367A (en) * 2008-09-26 2010-04-08 Ntt Docomo Inc Radio communication system, radio communication terminal, radio communication base station, and radio communication method
US8310996B2 (en) 2006-08-07 2012-11-13 Qualcomm Incorporated Conditional scheduling for asynchronous wireless communication
US8340027B2 (en) 2006-08-07 2012-12-25 Qualcomm Incorporated Monitor period for asynchronous wireless communication
JP2013059128A (en) * 2012-12-27 2013-03-28 Toshiba Corp Wireless communication device
US8416762B2 (en) 2006-08-07 2013-04-09 Qualcomm Incorporated Message exchange scheme for asynchronous wireless communication
US8737313B2 (en) 2006-08-07 2014-05-27 Qualcomm Incorporated Transmit time segments for asynchronous wireless communication
US9008002B2 (en) 2006-08-07 2015-04-14 Qualcomm Incorporated Conditional requests for asynchronous wireless communication

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010500828A (en) * 2006-08-07 2010-01-07 クゥアルコム・インコーポレイテッドQualcomm Incorporated Monitoring period for asynchronous wireless communication
US8737313B2 (en) 2006-08-07 2014-05-27 Qualcomm Incorporated Transmit time segments for asynchronous wireless communication
US8310996B2 (en) 2006-08-07 2012-11-13 Qualcomm Incorporated Conditional scheduling for asynchronous wireless communication
US8340027B2 (en) 2006-08-07 2012-12-25 Qualcomm Incorporated Monitor period for asynchronous wireless communication
JP2013051689A (en) * 2006-08-07 2013-03-14 Qualcomm Inc Conditional requests for asynchronous wireless communication
US8416762B2 (en) 2006-08-07 2013-04-09 Qualcomm Incorporated Message exchange scheme for asynchronous wireless communication
US9008002B2 (en) 2006-08-07 2015-04-14 Qualcomm Incorporated Conditional requests for asynchronous wireless communication
US9661649B2 (en) 2006-08-07 2017-05-23 Qualcomm Incorporated Determining a transmit parameter for wireless communication
JP2010081367A (en) * 2008-09-26 2010-04-08 Ntt Docomo Inc Radio communication system, radio communication terminal, radio communication base station, and radio communication method
JP2013059128A (en) * 2012-12-27 2013-03-28 Toshiba Corp Wireless communication device

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