WO2010050599A1 - Radio communication device - Google Patents

Radio communication device Download PDF

Info

Publication number
WO2010050599A1
WO2010050599A1 PCT/JP2009/068723 JP2009068723W WO2010050599A1 WO 2010050599 A1 WO2010050599 A1 WO 2010050599A1 JP 2009068723 W JP2009068723 W JP 2009068723W WO 2010050599 A1 WO2010050599 A1 WO 2010050599A1
Authority
WO
WIPO (PCT)
Prior art keywords
transmission
field
frame
directional
physical header
Prior art date
Application number
PCT/JP2009/068723
Other languages
French (fr)
Japanese (ja)
Inventor
清 利光
雅裕 高木
智哉 旦代
Original Assignee
株式会社 東芝
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 株式会社 東芝 filed Critical 株式会社 東芝
Publication of WO2010050599A1 publication Critical patent/WO2010050599A1/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0408—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas using two or more beams, i.e. beam diversity
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0686—Hybrid systems, i.e. switching and simultaneous transmission
    • H04B7/0695—Hybrid systems, i.e. switching and simultaneous transmission using beam selection
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W72/00—Local resource management
    • H04W72/20—Control channels or signalling for resource management
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
    • H04W16/24—Cell structures
    • H04W16/28—Cell structures using beam steering

Definitions

  • the present invention relates to a wireless communication apparatus that communicates with a plurality of wireless stations, such as a wireless local area network (LAN).
  • LAN wireless local area network
  • a directional repetitive transmission technique has been proposed in which transmission is performed while switching between a plurality of directional beams in different directions in a millimeter-wave wireless system in which the straightness of radio waves is strong (see, for example, Patent Document 1).
  • this directional repetitive transmission technology it is possible to repeatedly transmit radio signals for channel reservation while beam directivity control in different directions, so that channel reservation information can be notified to a wide range of wireless terminals. it can. That is, by using the directional repetitive transmission technology, a wide range of wireless terminals can receive channel reservation information, and the solution of the hidden terminal problem can be expected.
  • the increase in overhead due to the repeated transmission of radio signals, and the resulting decrease in throughput have become problems. For example, when the number of repeated transmissions is four, the throughput is one fourth.
  • reception of a radio signal for channel reservation transmitted in directional repetitive transmission fails, then it is transmitted despite the fact that the radio signal carrying the payload is being transmitted. There is also the possibility of making a wrong decision. If the radio signal carrying the payload is also subjected to directional repetitive transmission, the above-mentioned erroneous judgment can be alleviated, but the overhead will increase and the throughput will deteriorate. That is, the reliability at the time of notifying information necessary for career sense was low.
  • the processing to be performed next can not be executed until all the directional repetitively transmitted wireless signals are received, the effect of reducing the power consumption of the reception processing can not be sufficiently obtained.
  • the present invention has been made in view of the above circumstances, and an object thereof is to provide a wireless communication apparatus capable of solving the hidden terminal problem without reducing the throughput.
  • a first field including a physical header to which information indicating a scheduled period for using a wireless circuit for communication with a destination is added, and the first field.
  • a transmission frame generation unit that generates a transmission frame including a subsequent second field including a payload, and switching a plurality of directional beams with different directions for each of the first field and the second field
  • a wireless communication apparatus comprising: a transmitter configured to transmit the transmission frame by selectively using a first mode to be formed and a second mode to form a directional beam in the direction of the destination.
  • FIG. 1 is a block diagram showing an example of the configuration of a wireless communication apparatus according to the first embodiment.
  • FIG. 2 is a diagram showing an example of a directional beam formed by the wireless communication apparatus of FIG.
  • FIG. 3 is a diagram showing an example of the format of a transmission frame.
  • FIG. 4 is a diagram showing an example of the format of a conventional physical header.
  • FIG. 5 is a diagram showing an example of a network configuration configured by the wireless communication apparatus of FIG.
  • FIG. 6 is a diagram showing an example of conventional directional repetitive transmission.
  • FIG. 7A is a diagram showing an example of typical frame exchange defined in a wireless LAN.
  • FIG. 7B is a diagram showing an example in which directional repetitive transmission is applied in the frame exchange of FIG. 7A.
  • FIG. 8A is a diagram illustrating another example in which directional repetitive transmission is applied.
  • FIG. 8B is a diagram illustrating another example in which directional repetitive transmission is applied.
  • FIG. 8C is a diagram illustrating another example in which directional repetitive transmission is applied.
  • FIG. 8D is a diagram illustrating another example in which directional repetitive transmission is applied.
  • FIG. 9 is a diagram showing a configuration example of a physical header in the first embodiment.
  • FIG. 10 is a flowchart showing the procedure of transmission frame generation processing.
  • FIG. 11 is a diagram showing a beam control method when transmitting a transmission frame.
  • FIG. 12 is a flowchart showing the procedure of the receiving operation when the frame including the physical header shown in FIG. 9 is received.
  • FIG. 13A is a diagram for explaining a channel scheduled period.
  • FIG. 13A is a diagram for explaining a channel scheduled period.
  • FIG. 13B is a diagram for explaining a channel scheduled period.
  • FIG. 14A is a diagram showing an example of frame exchange in the first embodiment.
  • FIG. 14B is a diagram showing an example of frame exchange in the first embodiment.
  • FIG. 15A is a diagram showing another example of frame exchange in the first embodiment.
  • FIG. 15B is a diagram showing another example of frame exchange in the first embodiment.
  • FIG. 15C is a diagram showing another example of frame exchange in the first embodiment.
  • FIG. 15D is a diagram showing another example of frame exchange in the first embodiment.
  • FIG. 16A is a diagram showing another example of frame exchange in the first embodiment.
  • FIG. 16B is a diagram showing another example of frame exchange in the first embodiment.
  • FIG. 16C is a diagram showing another example of frame exchange in the first embodiment.
  • FIG. 16A is a diagram showing another example of frame exchange in the first embodiment.
  • FIG. 16B is a diagram showing another example of frame exchange in the first embodiment.
  • FIG. 16C is
  • FIG. 16D is a flowchart showing the procedure of transmission control processing in the frame exchange of FIGS. 16A and 16C.
  • FIG. 17A is a diagram showing an example of frame exchange in the case of CTS-to-self.
  • FIG. 17B is a diagram showing an example of frame exchange in the case of CTS-to-self.
  • FIG. 18A is a diagram illustrating another example of frame exchange in the case of CTS-to-self.
  • FIG. 18B is a diagram illustrating another example of frame exchange in the case of CTS-to-self.
  • FIG. 19A is a diagram illustrating another example of frame exchange in the case of CTS-to-self.
  • FIG. 19B is a diagram illustrating another example of frame exchange in the case of CTS-to-self.
  • FIG. 19A is a diagram illustrating another example of frame exchange in the case of CTS-to-self.
  • FIG. 19B is a diagram illustrating another example of frame exchange in the case of CTS-to-self.
  • FIG. 19C is a diagram illustrating another example of frame exchange in the case of CTS-to-self.
  • FIG. 20A is a diagram illustrating an example of frame exchange when RTS / CTS exchange or CTS-to-self transmission is not performed.
  • FIG. 20B is a diagram illustrating an example of frame exchange when RTS / CTS exchange or CTS-to-self transmission is not performed.
  • FIG. 20C is a diagram illustrating an example of frame exchange when RTS / CTS exchange or CTS-to-self transmission is not performed.
  • FIG. 20D is a diagram illustrating an example of frame exchange when RTS / CTS exchange or CTS-to-self transmission is not performed.
  • FIG. 21A is a diagram showing an example of frame exchange in the case of burst transmission of data.
  • FIG. 21A is a diagram showing an example of frame exchange in the case of burst transmission of data.
  • FIG. 21A is a diagram showing an example of frame exchange in the case of burst transmission of data
  • FIG. 21B is a diagram showing an example of frame exchange in the case of burst transmission of data.
  • FIG. 21C is a diagram showing an example of frame exchange in the case of burst transmission of data.
  • FIG. 21D is a diagram showing an example of frame exchange in the case of burst transmission of data.
  • FIG. 22 is a diagram showing a configuration example of a physical header in the second embodiment.
  • FIG. 23 is a flowchart illustrating the procedure of transmission control processing of the wireless communication apparatus according to the second embodiment.
  • FIG. 24A is a diagram illustrating an example in the case where the directivity of a beam at the time of Data transmission is not appropriate.
  • FIG. 24B is a diagram showing an example in the case where the directivity of the beam at the time of Data transmission is not appropriate.
  • FIG. 24A is a diagram illustrating an example in the case where the directivity of a beam at the time of Data transmission is not appropriate.
  • FIG. 24B is a diagram showing an example in the case where the
  • FIG. 25A is a block diagram illustrating a configuration example of a wireless communication device according to a third embodiment.
  • FIG. 25B is a block diagram illustrating another configuration example of the wireless communication device according to the third embodiment.
  • FIG. 26 is a diagram showing a configuration example of a physical header in the third embodiment.
  • FIG. 27 is a flowchart showing the reception operation of the wireless communication apparatus according to the third embodiment.
  • FIG. 28 is a diagram showing processing when the destination address is not addressed to the own station.
  • FIG. 29A is a diagram showing an operation of transmitting a channel estimation signal.
  • FIG. 29B is a diagram illustrating an operation of transmitting a channel estimation signal.
  • FIG. 30A is a diagram showing an operation of transmitting a beam control signal.
  • FIG. 30B is a diagram showing an operation of transmitting a beam control signal.
  • FIG. 31 is a diagram illustrating an example of a network configuration configured by the wireless communication device according to the fourth embodiment.
  • FIG. 32 is a diagram showing an example of the configuration of a physical header in the fourth embodiment.
  • FIG. 33 is a flowchart showing the reception operation of the wireless communication apparatus according to the fourth embodiment.
  • FIG. 34A is a diagram illustrating an example of frame exchange of the wireless communication device according to the fourth embodiment.
  • FIG. 34B is a diagram illustrating an example of frame exchange of the wireless communication device according to the fourth embodiment.
  • FIG. 35 is a diagram showing another example of the configuration of the physical header.
  • FIG. 36 is a block diagram showing another configuration example of the wireless communication apparatus.
  • FIG. 1 is a block diagram showing the configuration of a wireless communication apparatus according to the first embodiment of the present invention.
  • the wireless communication device 1 includes an antenna unit 11, a transmission / reception unit 12, a transmission frame generation unit 13, and a reception frame analysis unit 14.
  • the transmission / reception unit 12 includes an RF unit 121, a beam forming unit 122, and a control unit 123.
  • the antenna unit 11 is configured by an adaptive array antenna including a plurality of antenna elements.
  • the transmission / reception unit 12 converts the transmission frame generated by the transmission frame generation unit 13 into an RF signal via the beam forming unit 122 and the RF unit 121, and transmits the RF signal from the antenna unit 11.
  • the transmission / reception unit 12 converts the RF signal arriving at the antenna unit 11 into a reception signal via the RF unit 121 and the beam forming unit 122, and supplies frame data included in the reception signal to the reception frame analysis unit 14.
  • the beam forming unit 122 switches and forms a plurality of directional beams different in direction by the antenna unit 11 in accordance with directivity control by the control unit 123.
  • FIG. 2 shows an example of a directional beam formed by the wireless communication device 1.
  • first mode directional repetitive transmission
  • second mode non-repetitive transmission
  • FIG. 3 is an example of the format of a transmission frame generated by the transmission frame generation unit 13.
  • the transmission frame is a preamble for signal synchronization, a physical header, a frame check sequence of the physical header (FCS1), a MAC header, a payload, a MAC header and a frame check sequence of the payload (FCS2) And consists of Since FCS1 is a check sequence for the header, it may be called Header Error Check (HEC).
  • FCS1 is a check sequence for the header, it may be called Header Error Check (HEC).
  • HEC Header Error Check
  • FIG. 4 shows an example of a conventional physical header format.
  • the physical header contains information on the packet length, the subsequent MAC header, the payload, and the transmission rate at which the FCS 2 is transmitted.
  • the packet length can be expressed in bit length or in time length. By using the information of the transmission rate, the bit length can be converted to a time length, and the time length can be converted to a bit length.
  • FCS2 requires more bits than FCS1.
  • FCS2 even if an error is detected or missed in the physical header, it is an influence on communication characteristics such as throughput and efficiency, but missed detection of the MAC header or payload may lead to a malfunction. Therefore, a code with higher error detection capability is used in FCS2 than in FCS1.
  • the preamble includes a signal for achieving synchronization
  • a method of providing a channel estimation field for estimating the state of the wireless channel and transmission rate information of a subsequent physical header, etc. is also considered.
  • the frame check sequence of the preamble, the physical header and the physical header is defined as a first field
  • the MAC header, the payload, the MAC header and the frame check sequence of the payload (FCS2) is a second field. Define as a field.
  • FIG. 5 shows an example of the network configuration configured by the wireless communication device 1.
  • FIG. 5 illustrates an example of a network configured by the wireless communication device 1 operating as a base station (access point) or a terminal station (station).
  • the terminal stations STA1 and STA2 connect to the network via the base station AP.
  • FIG. 6 shows an example of conventional directional repetitive transmission.
  • a certain unit of radio signal in wireless transmission of a transmission frame is defined, and the units of the radio signal are sequentially directed beam Repeat sending 4 times while switching.
  • OFDM transmission if one symbol is used as a unit, the same symbol is repeatedly transmitted four times while switching the directional beam. For example, when the preamble is composed of eight symbols, the first symbol is transmitted four times, and then the second symbol is transmitted four times. Since the same symbol is repeatedly transmitted while switching the directivity of the beam, a wide range of wireless communication devices can receive this frame. However, there is a problem that the transmission efficiency is degraded by the number of repeated transmissions.
  • FIG. 7A shows a representative frame exchange (RTS-CTS-Data-Ack) defined in the IEEE 802.11 wireless LAN.
  • the terminal station to be sent sends an RTS (Request to Send) to the destination, and after receiving a CTS (Clear to Send: ready to receive) sent from the destination according to the RTS, It sends data.
  • FIG. 7B shows an example in the case where the directional repetitive transmission shown in FIG. 6 is applied to this frame exchange. In FIG. 7B, since the transmission time length of each frame is quadrupled, it is understood that transmission efficiency is significantly reduced when directional repetitive transmission is used, as is apparent from FIGS. 7A and 7B. .
  • the communication area of this wireless communication apparatus is the sum of the communication areas of directional beams 1 to 4.
  • the other party of communication is located in any of directional beams 1 to 4, it is possible to indicate to other terminals located in the other communication area that communication is in progress, so the hidden terminal It is possible to avoid unnecessary radio signal collisions due to problems.
  • FIG. 7B there is a method of always transmitting a wireless signal to each communication area to indicate that the channel is busy.
  • FIG. 9 shows a configuration example of the physical header in the first embodiment.
  • FIG. 9 shows the physical header of FIG. 4 added with a channel reservation period (PHY duration (NAV: Network Allocation Vector, communication scheduled period)).
  • PHY duration is not the packet length (length) of this packet itself, but is information on a frame exchange period scheduled to follow thereafter.
  • FIG. 10 is a flowchart showing the procedure of transmission frame generation processing.
  • the transmission frame generation unit 13 generates a preamble for signal synchronization (step S1a).
  • a channel scheduled period to be added to the physical header is calculated (step S2a).
  • the calculation method of the channel scheduled period will be described later.
  • the transmission frame generation unit 13 generates a physical header to which the calculated channel scheduled period is added (step S3a), and generates a frame check sequence (FCS1) for the physical header (step S4a).
  • FCS1 frame check sequence
  • the transmission frame generation unit 13 generates a MAC address and a payload following the first field (step S5a), and generates a frame check sequence (FCS2) for the MAC address and the payload (step S6a).
  • a second field including the MAC address, the payload, the MAC address, and the frame check sequence (FCS2) for the payload is generated.
  • FIG. 11 shows a beam control method when transmitting the generated transmission frame.
  • the transmission / reception unit 1 transmits, in the transmission frame, a first field including a preamble, a physical header, and a frame check sequence (FCS1) for the physical header by directional repetitive transmission. That is, the control unit 123 repeatedly transmits each symbol in the first field four times while switching a plurality of directional beams in different directions by the beam forming unit 122.
  • FCS1 frame check sequence
  • the second field including the MAC address following the first field, the payload, the MAC address, and the frame check sequence (FCS2) for the payload is transmitted by non-repetitive transmission.
  • the control unit 123 causes the beam forming unit 122 to form a directional beam in the direction of the destination included in the MAC address and transmits the second field.
  • FIG. 12 is a flowchart showing the procedure of the receiving operation when the frame including the physical header shown in FIG. 9 is received.
  • the reception frame analysis unit 14 receives the first field (step S1 b)
  • the reception frame analysis unit 14 acquires a channel scheduled period included in the physical header (step S2 b).
  • the second field is further received (step S3b)
  • the MAC header is acquired from the received second field (step S4b). If the destination address included in the acquired MAC header is addressed to the local station (step S5b), the transmission / reception unit 12 performs the subsequent transmission / reception process (step S6b).
  • the reception frame analysis unit 14 notifies the control unit 123 so that the transmission / reception unit 12 can The transmission of the channel scheduled period is prohibited (step S7b).
  • the start of the channel scheduled period to be added to the physical header is immediately after the end of the transmission of the first field. That is, it is set as the scheduled time when transmission of the second field is started. Also, when adding a channel scheduled period to the MAC header, the transmission completion time of the second field is set as the start time of the channel scheduled period. That is, it is assumed that the start time of the scheduled channel period to which the physical header is added and the start time of the scheduled channel period to be added to the MAC header are different. However, the end time of the channel scheduled period is the same, and is the end time of the frame exchange.
  • the channel scheduled period included in the physical header of RTS in FIG. 13A is 500 [us]
  • the frame length of the second field of RTS is 30 [us].
  • the wireless station that could receive RTS but could not receive CTS and the wireless station that could not receive RTS but could receive CTS.
  • the channel scheduled period recognized by can be made the same value. Further, when calculating the channel scheduled period described in the physical header at the time of Data transmission, it can be calculated based on the channel scheduled period included in the received CTS MAC frame.
  • the channel scheduled period is similarly calculated and set.
  • FIG. 14A and 14B show an example of frame exchange in the first embodiment.
  • FIG. 14A only the first field of the RTS frame on the base station side is transmitted by the directional repetitive transmission scheme, and non-repetitive transmission is performed using the directional beam of the direction of the destination after the second field of the RTS. .
  • FIG. 14B only the first field of the CTS frame on the base station side is transmitted by the directional repetitive transmission scheme, and non-repetitive transmission is performed using the directional beam in the direction of the destination after the CTS second field. In this way, it is possible to further improve the communication efficiency while obtaining the same effect as that of FIG. 8D described above.
  • FIGS. 15A to 15D show another example of frame exchange in the first embodiment.
  • FIGS. 15A and 15B transmit only the first field of the RTS and CTS frame by the directional repetitive transmission method, and transmit non-repetitively using the directional beam of the direction of the destination after the second field of the RTS and CTS frame It is.
  • communication efficiency can be improved while obtaining the same effects as those of FIGS. 8A and 8B described above.
  • the first fields of the Data and Ack frames following RTS / CTS exchange may also be transmitted by the directional repetitive transmission method.
  • the channel scheduled period can be grasped, so that the hidden terminal problem can be solved. Reliability can be improved. In particular, it is effective in the case where data and Ack frames are continuously burst transmitted.
  • FIGS. 16A to 16C show other examples of frame exchange.
  • FIGS. 15A to 15D as shown in FIGS. 16A and 16C, only the first field of the frame transmitted by the base station may be transmitted by the directional repetitive transmission scheme. As a result, it is possible to efficiently notify the terminal station in the communication area of the base station of the information on the scheduled channel period and the like.
  • FIG. 16D is a flowchart showing the procedure of the transmission control process of the control unit 123 in such a case.
  • the control unit 123 selects the transmission method of the first field according to the information (base station / terminal station) indicating the device type (step S1). For example, when the device type is a base station, the directional repetitive transmission method is selected, and when the device type is a terminal station, the non-repetitive transmission method is selected.
  • step S1 step S2
  • the control unit 123 transmits the first field in the directional repetitive transmission scheme (step S3), and transmits the second field in the non-repetitive transmission scheme.
  • Step S4 the control unit 123 transmits the first field and the second field in the non-repetitive transmission scheme.
  • the terminal station may transmit only one field of RTS to be transmitted first to acquire a channel in a directional repetitive transmission scheme. As a result, it is possible to quickly notify other terminal stations located in the vicinity of the terminal station that transmits the RTS, of the information regarding the channel scheduled period.
  • the wireless communication device 1 transmits a CTS signal triggered by the reception of the RTS signal addressed to the local station, the CTS signal can be transmitted without receiving the RTS addressed to the local station. It may be defined. That is, it is also called "CTS-to-self" because it is a CTS signal addressed to the own station.
  • FIG. 17A and 17B show an example of frame exchange in the case of CTS-to-self.
  • FIG. 17A shows the case of transmission from the base station to the terminal station by CTS-to-self
  • FIG. 17B shows the case of transmission from the terminal station to the base station by CTS-to-self.
  • FIG. 17A is to transmit only the first field of the CTS frame transmitted from the base station by the directional repetitive transmission method.
  • FIG. 17B only the first field of the CTS frame transmitted from the terminal station is transmitted by the directional repetitive transmission method.
  • FIGS. 18A and 18B show another example of frame exchange in the case of CTS-to-self.
  • FIG. 18A shows the case of transmission from the base station to the terminal station by CTS-to-self
  • FIG. 18B shows the case of transmission from the terminal station to the base station by CTS-to-self.
  • FIGS. 18A and 18B transmit the first field of each frame of CTS, Data and Ack by the directional repetitive transmission method.
  • FIG. 19A, 19B and 19C show another example of frame exchange in the case of CTS-to-self.
  • FIG. 19A shows the case where only the first field of the frame transmitted from the base station is transmitted by the directional repetitive transmission method
  • FIG. 19B shows the first field of the frame transmitted from the base station and the first transmission of the terminal station.
  • the first field of the CTS frame is transmitted by the directional repetitive transmission method
  • FIG. 19C is to transmit only the first field of the frame to be transmitted first from the base station by the directional repetitive transmission scheme.
  • FIGS. 20A to 20D show an example of frame exchange when RTS / CTS exchange or CTS-to-self transmission is not performed.
  • FIGS. 20A and 20B show data transmission from the base station to the terminal station
  • FIGS. 20C and 20D show data transmission from the terminal station to the base station.
  • 20A and 20C transmit the first field of the transmission frame from both the base station and the terminal station in the directional repetitive transmission scheme
  • FIGS. 20B and 20D transmit only the first field of the transmission frame from the base station Are transmitted by the directional repetitive transmission method.
  • 21A to 21D show an example of frame exchange in the case of burst transmission of data.
  • 21A and 21C show burst transmission of data from the base station to the terminal station
  • FIGS. 21B and 21D show burst transmission of data from the terminal station to the base station.
  • 21A and 21B transmit the first field of the transmission frame from both the base station and the terminal station in the directional repetitive transmission scheme
  • FIGS. 21C and 21D transmit only the first field of the transmission frame from the base station Are transmitted by the directional repetitive transmission method.
  • 21A to 21D show an example of frame exchange in the case of burst transmission of only Data without transmitting RTS / CTS, CTS-to-self, etc. However, RTS / CTS is performed before Data burst. A method of exchanging or sending CTS-to-self may be used.
  • Second Embodiment In the second embodiment, a method will be described in which the directional repetitive transmission scheme and the non-repetitive transmission scheme are switched and transmitted according to the type of transmission frame and the like.
  • the configuration of the second embodiment is the same as the configuration of FIG. 1 described above, and therefore will be described using FIG.
  • the configuration of the physical header and the operation of the control unit 123 are different.
  • FIG. 22 shows a configuration example of a physical header in the second embodiment.
  • FIG. 22 shows the physical header of FIG. 9 added with information related to the beam control identifier.
  • the beam control identifier is an identifier for indicating how to transmit the second field. By using this identifier, it is notified to the other party whether the second field is to be transmitted by non-repetitive transmission using one directional beam or to be transmitted by directional repetitive transmission as in the first field. can do. For example, if the destination address is a broadcast, it is transmitted by the directional repetitive transmission method after the MAC header so that all terminals capable of communicating with the local station can receive, and if the destination address is a specific terminal station , Transmit using a directional beam in a direction that the terminal station can receive.
  • this beam control identifier is set to an appropriate value. If the destination address is a broadcast address, the beam control identifier may not be necessary if it is determined in advance to always transmit in the directional repetitive transmission method.
  • FIG. 23 is a flowchart of the transmission control process of the control unit 123.
  • the control unit 123 selects the transmission method of the first field according to the frame type information (step S 1 c). For example, when the frame type information is an RTS frame, it is assumed that a directional repetition transmission scheme is selected.
  • the control unit 123 selects the directional repetitive transmission scheme in step S1c (step S2c)
  • the control unit 123 transmits the first field in the directional repetitive transmission scheme (step S3c).
  • step S4c when the destination address is a broadcast (step S4c), the second field is transmitted by the directional repetitive transmission method (step S4c).
  • step S7c When the destination address is unicast in step S4c, the control unit 123 transmits the second field by the non-repetitive transmission method (step S7c).
  • step S6c and S7c when the non-repetitive transmission scheme is selected in step S1c, the control unit 123 transmits the first field and the second field in the non-repetitive transmission scheme (steps S6c and S7c).
  • the terminal station moves, it is not necessary to transmit in all directions using directional repetitive transmission, but it is preferable to transmit with multiple directional beams including directions that may move. Is good. Therefore, for example, when there are beams having eight types of directivity, the first field is transmitted by the eight-time directivity repetitive transmission scheme, and the second field is three of the eight types of directional beams. Transmission using a three-times directional repeat transmission scheme.
  • the receiving side needs to know the number of repetitions, but according to the present embodiment, the number of repetitions is determined in consideration of the destination address, the moving direction of the communication partner, etc. Therefore, it is possible to select the necessary number of times as appropriate.
  • the transmission method of the second field is described using an example of transmission using one directional beam. However, if a beam control identifier is used, the number of repetitions can be dynamically changed as necessary. It can be applied to
  • FIGS. 24A and 24B show examples of cases where the beam directivity at the time of Data transmission is not appropriate in frame exchange using the directional repetitive transmission shown in FIGS. 9A and 9B.
  • the base station AP transmits Data using a directional beam suitable for transmission to the terminal station STA, but when there is a change in the wireless communication environment, the directional beam is not appropriate, and as a result
  • Data can not be correctly transmitted to the destination terminal station STA.
  • the base station AP retransmits the Data using the directional repetitive transmission method or the like, but if this method does not actually transmit Data, the directional beam is correct or not. I can not judge.
  • FIG. 25A and 25B are block diagrams showing an example of the configuration of a wireless communication apparatus according to the third embodiment.
  • FIG. 25A shows the configuration of FIG. 1 provided with a channel estimation signal generation unit 15.
  • FIG. 25B is obtained by providing the beam selection signal generation unit 16 in the configuration of FIG. Note that both the channel estimation signal generation unit 15 and the beam selection signal generation unit 16 may be provided in the configuration of FIG. 1.
  • the channel estimation signal generation unit 15 generates a sounding signal (channel estimation signal) that the transmission source uses to estimate an appropriate channel.
  • the beam selection signal generation unit 16 generates information (a beam selection signal) for enabling the transmission source to select an optimal directional beam.
  • FIG. 26 shows a configuration example of the physical header in the third embodiment.
  • destination address information is added to the physical header of FIG. 6A. This destination address is usually information to be added to the MAC header, but here it is also added to the physical header. A destination address may or may not be added to the MAC header.
  • FIG. 27 is a flowchart showing the reception operation of the wireless communication apparatus according to the third embodiment.
  • the reception frame analysis unit 14 acquires a channel scheduled period included in the physical header (step S2d) and acquires a destination address included in the physical header (step S3d). . If the acquired destination address is addressed to the own station (step S4d), the reception frame analysis unit 14 attempts to receive the second field (step S5d). If the second field is received in step S5d, the transmission / reception unit 12 performs the subsequent transmission / reception process (step S6d). On the other hand, when the destination address is not addressed to the own station in step S4d, the transmission / reception unit 12 stops transmission of the channel scheduled period (step S7d). If the second field can not be received in step S5d of FIG. 27, the channel estimation signal generation unit 15 generates a channel estimation signal, or the beam selection signal generation unit 16 generates a beam selection signal. Perform (step S8d).
  • the reception process may be stopped.
  • the terminal station STA2 receives a radio frame addressed to the terminal station STA1
  • communication between the base station AP and the terminal station STA1 is performed during a channel scheduled period included in the physical header.
  • stop the reception processing stop the power supply or stop the clock supply. Since the second field transmitted by the base station AP or the terminal station STA1 is transmitted using a directional beam directed to the destination direction, the terminal station STA2 may not be able to detect the power, but It is determined that communication between the base station AP and the terminal station STA1 is being performed during the included channel scheduled period. As a result, wasteful power consumption can be reduced, leading to lower power consumption.
  • 29A and 29B show the case where the first field including the physical header to which the destination address addressed to the own station is added is received.
  • the subsequent information after the second field can not be received correctly (error in frame check sequence)
  • the reception frame analysis unit 14 of the terminal station STA can determine that the beam formed by the base station AP for itself is not appropriate.
  • the modulation scheme used for the first field transmission, the error correction scheme, the modulation scheme used for the second field transmission, the case where the error correction scheme is the same, or the modulation scheme used for the second field transmission The decision is more appropriate if the error correction scheme is more robust. Further, as shown in FIG. 29B, even if the reception level in the second field and onwards is rapidly deteriorated and reception is hardly possible, the terminal station STA determines that the beam formed by the base station AP to the own station is not appropriate. Can. It is also possible to compare the received power of the first field and the received power of the second field, and determine that the beam is not appropriate if the difference is greater than or equal to a predetermined threshold.
  • the channel estimation signal generation unit 15 of the terminal station STA requires the base station AP to perform channel estimation for the base station AP after the reception of RTS is completed and a predetermined time has elapsed. Transmit channel estimation signal. Further, even if the second and subsequent fields of the RTS can not be received at all as shown in FIG. 29B, since the information on the RTS frame length is added to the physical header of the RTS, the terminal station STA Since the end time of the RTS frame can be grasped, the timing to transmit the channel estimation signal can be recognized.
  • FIGS. 30A and 30B show the case where the first field including the physical header to which the destination address addressed to the own station is added is received.
  • the terminal station STA when the identifier of the beam being used can be recognized from the signal of the first field transmitted by directional repetition, the terminal station STA is the best of the beams used by the base station AP. Can be selected.
  • the beam selection signal generation unit 16 of the terminal station STA completes the reception of RTS when the RTS frame is not correctly received or when the second field of RTS is not received. After a predetermined time has elapsed, the base station AP transmits a beam selection signal for notifying an optimum beam.
  • the base station AP can determine the optimum beam more quickly than in the method shown in FIGS. 24A and 24B, and can perform retransmission processing efficiently.
  • the base station AP can determine the optimum beam more quickly than in the method shown in FIGS. 24A and 24B, and can perform retransmission processing efficiently.
  • the base station AP can determine the optimum beam more quickly than in the method shown in FIGS. 24A and 24B, and can perform retransmission processing efficiently.
  • the base station AP can determine the optimum beam more quickly than in the method shown in FIGS. 24A and 24B, and can perform retransmission processing efficiently.
  • the RTS frame is correctly received, if the Data frame can not be received correctly, although the beam directivity is correct, it is determined that the selected modulation scheme is inappropriate, and the beam directivity is determined. It is possible to change to a more robust modulation scheme and coding scheme while maintaining.
  • a channel scheduled period is notified to a wide range of radio stations, and which radio station the radio frame is addressed to It can be notified. Therefore, after analyzing the physical header, the wireless station not designated as the destination does not need to receive data after the second field of the frame, so the reception process may be stopped to save power. it can. Also, it is possible to know that the channel scheduled period may stop the reception process.
  • the amount of information of the destination address added to the physical header may be compressed by a reversible compression method such as a hash function in order to reduce the overhead. Alternatively, it may be compressed by an irreversible compression method. As a lossy compression method, it is also possible to simply use the lower few bits of the MAC address as the destination address to be added to the physical header.
  • the wireless packet can be addressed to the local station by adding destination address information to the MAC header and analyzing information related to the destination address included in the physical header. Determine if there is sex or not. If there is a possibility of being addressed to the own station, reception processing may be continued, and the destination address added to the MAC header may be checked to finally determine whether the address is addressed to the own station.
  • FIG. 31 shows an example of the network configuration of the wireless communication apparatus according to the fourth embodiment.
  • the terminal stations STA1-1 to 1-2 are connected to the base station AP1, and the terminal stations STA2-1 to 2-2 are connected to the base station 2.
  • the terminal station STA2-2 is located in the communication area of both the base station AP1 and the base station AP2. Therefore, the terminal station STA2-2 can receive not only the radio signal transmitted by the base station AP2, but also the radio signal transmitted by the base station AP1.
  • the base station AP1 also reserves a channel for the terminal station STA2-2 connected to the base station 2, and there is a risk that the channel efficiency improvement effect by spatial multiplexing may be reduced.
  • FIG. 32 shows a configuration example of the physical header in the fourth embodiment.
  • FIG. 32 shows the physical header of FIG. 6A added with a network identifier (information for identifying a wireless channel) for identifying a wireless channel.
  • FIG. 33 is a flowchart showing the reception operation of the wireless communication apparatus according to the fourth embodiment.
  • the reception frame analysis unit 14 acquires a channel scheduled period included in the physical header (step S2e) and acquires a network identifier included in the physical header (step S3e). .
  • the reception frame analysis unit 14 determines whether or not the network identifier of the network to which the own station belongs is identical to the acquired network identifier (step S4e), and is different from the network identifier to which the own station belongs Ignores the channel reservation information contained in the physical header. That is, it is not determined that the channel is reserved.
  • step S4e determines whether the network identifier of the network to which the own station belongs is identical to the acquired network identifier, and if the second field is further received (step S5e).
  • the received second The MAC header is acquired from the field of (step S6e). If the destination address included in the acquired MAC header is addressed to the local station (step S7e), the transmission / reception unit 12 performs the subsequent transmission / reception process (step S8e).
  • step S9e transmission of the channel scheduled period is stopped (step S9e). If the destination address is not addressed to the local station in step S7e, the transmission / reception unit 12 stops transmission / reception of the channel scheduled period (step S10e).
  • the terminal stations STA1-1, STA1-2, and STA2-2 receive the radio signal transmitted to the terminal station STA1-1 by the base station AP1. Since the terminal station STA1-1 is a radio signal directed to itself, it continues to communicate with the base station AP1 thereafter.
  • the terminal station STA1-2 receives the first field of the RTS frame and determines that it is a signal of the network to which the own station belongs by the network identifier added to the physical header, it continues reception thereafter, but When the second field of is received, it is determined that the frame is not addressed to its own station. Therefore, transmission and reception processing is stopped during a period in which communication between the base station AP1 and the terminal station STA1-1 is being performed, that is, a channel scheduled period.
  • the terminal station STA2-2 when the terminal station STA2-2 receives the first field of the RTS frame, it detects from the network identifier added to the physical header that it is a signal of a network different from the network to which the own station belongs. Then, the terminal station STA2-2 cancels the channel scheduled period included in the physical header, and continues the reception process thereafter. Transmission processing can also be performed as needed. This is because, as shown in FIG. 31, when the network is different, in general, the signal transmitted from the terminal station STA2-2 to the base station AP2 is for the communication of the terminal station STA1-1 belonging to the base station AP1. Since the influence exerted is considered to be small, it is considered that spatial communication efficiency is improved if normal transmission and reception are continued rather than transmission suppression.
  • both the destination address and the network identifier are added to the physical header shown in FIG.
  • FIG. 34B when the terminal station STA1-2 receives the first field of the RTS frame, it is determined from the destination address contained in the physical header that the frame is not addressed to itself. Since the determination can be made, the transmission / reception process can be stopped earlier compared to the method of FIG. 34A, which is effective in further reducing power consumption.
  • the terminal station can grasp not only the information of the channel scheduled period but also the network identifier information, and thus belongs to another base station. It is no longer necessary to suppress transmission to the terminal station more than necessary. That is, simultaneous transmission between different network devices becomes possible, and space utilization efficiency can be improved.
  • the network identifier may be losslessly compressed or losslessly compressed to reduce the amount of information, similarly to the destination address.
  • the embodiment can be applied to the configuration example of the wireless communication apparatus of FIG. 36 using a sector antenna. That is, directional repeat transmission may be realized by transmitting an RF signal while sequentially switching a plurality of sector antennas having directivity. Then, based on this configuration, the channel estimation signal generation unit 15 as shown in FIG. 25A or the beam selection signal generation unit 16 in FIG. 25B may be provided.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Radio Transmission System (AREA)

Abstract

A radio communication device (1) includes: a transmission frame generation unit (13) which generates a transmission frame containing a first field containing a physical header having information indicating an expected period to be used by a radio line for communication with a destination and a second field following the first field and containing a payload; and a transmission reception unit (12) which transmits the transmission frame by selectively using a first mode for forming a plurality of directivity beams of different directions to be switched for each of the first field and the second field and a second mode for forming a directivity beam of the destination direction.

Description

無線通信装置Wireless communication device
　この発明は、無線ＬＡＮ（Local Area Network）のように複数の無線局間で相互に通信を行なう無線通信装置に関する。 The present invention relates to a wireless communication apparatus that communicates with a plurality of wireless stations, such as a wireless local area network (LAN).
　電波の直進性が強いミリ波無線システムで、方向の異なる複数の指向性ビームを切り替えながら送信を行う指向性反復伝送技術が提案されている（例えば、特許文献１を参照。）。この指向性反復伝送技術を用いれば、チャネルを予約するための無線信号を異なる方向にビーム指向性制御しながら繰り返し送信することができるため、広範囲の無線端末にチャネル予約の情報を通知することができる。つまり、指向性反復伝送技術を用いることにより、広範囲の無線端末がチャネル予約の情報を受信することができ、隠れ端末問題の解消が期待できる。その一方で、無線信号を繰り返し送信することによるオ－バヘッドの増大、その結果、スループットの低下が問題となっている。たとえば、繰り返し送信数を４回にする場合は、スループットは１／４になってしまう。 A directional repetitive transmission technique has been proposed in which transmission is performed while switching between a plurality of directional beams in different directions in a millimeter-wave wireless system in which the straightness of radio waves is strong (see, for example, Patent Document 1). By using this directional repetitive transmission technology, it is possible to repeatedly transmit radio signals for channel reservation while beam directivity control in different directions, so that channel reservation information can be notified to a wide range of wireless terminals. it can. That is, by using the directional repetitive transmission technology, a wide range of wireless terminals can receive channel reservation information, and the solution of the hidden terminal problem can be expected. On the other hand, the increase in overhead due to the repeated transmission of radio signals, and the resulting decrease in throughput have become problems. For example, when the number of repeated transmissions is four, the throughput is one fourth.
　また、指向性反復伝送で送信されたチャネル予約のための無線信号の受信に失敗した場合は、そのあと、実際にはペイロードを載せた無線信号が送信されているにも関わらず、送信されていないと誤った判断をする可能性もある。ペイロードを載せた無線信号も指向性反復伝送すれば、上述の誤判断を軽減することができるが、オ－バヘッドは増大し、スループットが劣化してしまう。つまり、キャリアセンスに必要な情報を通知する際の信頼性が低かった。 Also, if reception of a radio signal for channel reservation transmitted in directional repetitive transmission fails, then it is transmitted despite the fact that the radio signal carrying the payload is being transmitted. There is also the possibility of making a wrong decision. If the radio signal carrying the payload is also subjected to directional repetitive transmission, the above-mentioned erroneous judgment can be alleviated, but the overhead will increase and the throughput will deteriorate. That is, the reliability at the time of notifying information necessary for career sense was low.
　また、指向性反復伝送された無線信号を全て受信するまでは、次にすべき処理を実行できないため、受信処理の低消費電力化の効果が十分に得られなかった。 Further, since the processing to be performed next can not be executed until all the directional repetitively transmitted wireless signals are received, the effect of reducing the power consumption of the reception processing can not be sufficiently obtained.
特開平１１－１３６７３５号公報Japanese Patent Application Laid-Open No. 11-136735
　上述したように、従来の指向性反復伝送技術においては、スループットの低下、指向性ビーム制御の効率劣化、情報伝送の信頼性が低い、低消費電力化が十分でない、という問題があった。 As described above, in the conventional directional repetitive transmission technology, there is a problem that the throughput is lowered, the efficiency of directional beam control is deteriorated, the reliability of information transmission is low, and the reduction of power consumption is not sufficient.
　この発明は上記事情に着目してなされたもので、その目的とするところは、スループットを低下させることなく、隠れ端末問題を解消することができる無線通信装置を提供することにある。 The present invention has been made in view of the above circumstances, and an object thereof is to provide a wireless communication apparatus capable of solving the hidden terminal problem without reducing the throughput.
　上記目的を達成するためにこの発明の一態様は、無線回線を宛先との間の通信に使用する予定期間を示す情報を付加した物理ヘッダを含む第１のフィールドと、前記第１のフィールドに後続する、ペイロードを含む第２のフィールドとを含む送信フレームを生成する送信フレーム生成部と、前記第１のフィールド及び第２のフィールドのそれぞれに対して、方向の異なる複数の指向性ビームを切り替えて形成する第１のモードと前記宛先の方向に指向性ビームを形成する第２のモードとを選択的に用いて前記送信フレームを送信する送信部とを具備する無線通信装置を提供する。 In order to achieve the above object, according to one aspect of the present invention, there is provided a first field including a physical header to which information indicating a scheduled period for using a wireless circuit for communication with a destination is added, and the first field. A transmission frame generation unit that generates a transmission frame including a subsequent second field including a payload, and switching a plurality of directional beams with different directions for each of the first field and the second field A wireless communication apparatus comprising: a transmitter configured to transmit the transmission frame by selectively using a first mode to be formed and a second mode to form a directional beam in the direction of the destination.
　したがってこの発明によれば、スループットを低下させることなく、隠れ端末問題を解消することができる無線通信装置を提供することができる。 Therefore, according to the present invention, it is possible to provide a wireless communication apparatus capable of solving the hidden terminal problem without reducing the throughput.
図１は、第１の実施形態に係る無線通信装置の構成例を示すブロック図である。FIG. 1 is a block diagram showing an example of the configuration of a wireless communication apparatus according to the first embodiment. 図２は、図１の無線通信装置が形成する指向性ビームの一例を示す図である。FIG. 2 is a diagram showing an example of a directional beam formed by the wireless communication apparatus of FIG. 図３は、送信フレームのフォーマットの一例を示す図である。FIG. 3 is a diagram showing an example of the format of a transmission frame. 図４は、従来の物理ヘッダのフォーマットの一例を示す図である。FIG. 4 is a diagram showing an example of the format of a conventional physical header. 図５は、図１の無線通信装置が構成するネットワーク構成例を示す図である。FIG. 5 is a diagram showing an example of a network configuration configured by the wireless communication apparatus of FIG. 図６は、従来の指向性反復伝送の一例を示す図である。FIG. 6 is a diagram showing an example of conventional directional repetitive transmission. 図７Ａは、無線ＬＡＮで定義されている代表的なフレーム交換例を示す図である。FIG. 7A is a diagram showing an example of typical frame exchange defined in a wireless LAN. 図７Ｂは、図７Ａのフレーム交換において指向性反復伝送を適用した例を示す図である。FIG. 7B is a diagram showing an example in which directional repetitive transmission is applied in the frame exchange of FIG. 7A. 図８Ａは、指向性反復伝送を適用した他の例を示す図である。FIG. 8A is a diagram illustrating another example in which directional repetitive transmission is applied. 図８Ｂは、指向性反復伝送を適用した他の例を示す図である。FIG. 8B is a diagram illustrating another example in which directional repetitive transmission is applied. 図８Ｃは、指向性反復伝送を適用した他の例を示す図である。FIG. 8C is a diagram illustrating another example in which directional repetitive transmission is applied. 図８Ｄは、指向性反復伝送を適用した他の例を示す図である。FIG. 8D is a diagram illustrating another example in which directional repetitive transmission is applied. 図９は、第１の実施形態における物理ヘッダの構成例を示す図である。FIG. 9 is a diagram showing a configuration example of a physical header in the first embodiment. 図１０は、送信フレーム生成処理の手順を示すフローチャートである。FIG. 10 is a flowchart showing the procedure of transmission frame generation processing. 図１１は、送信フレームを送信する時のビーム制御方法を示す図である。FIG. 11 is a diagram showing a beam control method when transmitting a transmission frame. 図１２は、図９に示した物理ヘッダを含むフレームを受信した場合の受信動作の手順を示すフローチャートである。FIG. 12 is a flowchart showing the procedure of the receiving operation when the frame including the physical header shown in FIG. 9 is received. 図１３Ａは、チャネル予定期間について説明する図である。FIG. 13A is a diagram for explaining a channel scheduled period. 図１３Ｂは、チャネル予定期間について説明する図である。FIG. 13B is a diagram for explaining a channel scheduled period. 図１４Ａは、第１の実施形態におけるフレーム交換の一例を示す図である。FIG. 14A is a diagram showing an example of frame exchange in the first embodiment. 図１４Ｂは、第１の実施形態におけるフレーム交換の一例を示す図である。FIG. 14B is a diagram showing an example of frame exchange in the first embodiment. 図１５Ａは、第１の実施形態におけるフレーム交換の他の例を示す図である。FIG. 15A is a diagram showing another example of frame exchange in the first embodiment. 図１５Ｂは、第１の実施形態におけるフレーム交換の他の例を示す図である。FIG. 15B is a diagram showing another example of frame exchange in the first embodiment. 図１５Ｃは、第１の実施形態におけるフレーム交換の他の例を示す図である。FIG. 15C is a diagram showing another example of frame exchange in the first embodiment. 図１５Ｄは、第１の実施形態におけるフレーム交換の他の例を示す図である。FIG. 15D is a diagram showing another example of frame exchange in the first embodiment. 図１６Ａは、第１の実施形態におけるフレーム交換の他の例を示す図である。FIG. 16A is a diagram showing another example of frame exchange in the first embodiment. 図１６Ｂは、第１の実施形態におけるフレーム交換の他の例を示す図である。FIG. 16B is a diagram showing another example of frame exchange in the first embodiment. 図１６Ｃは、第１の実施形態におけるフレーム交換の他の例を示す図である。FIG. 16C is a diagram showing another example of frame exchange in the first embodiment. 図１６Ｄは、図１６Ａ、図１６Ｃのフレーム交換における送信制御処理の手順を示すフローチャートである。FIG. 16D is a flowchart showing the procedure of transmission control processing in the frame exchange of FIGS. 16A and 16C. 図１７Ａは、ＣＴＳ－ｔｏ－ｓｅｌｆの場合のフレーム交換の一例を示す図である。FIG. 17A is a diagram showing an example of frame exchange in the case of CTS-to-self. 図１７Ｂは、ＣＴＳ－ｔｏ－ｓｅｌｆの場合のフレーム交換の一例を示す図である。FIG. 17B is a diagram showing an example of frame exchange in the case of CTS-to-self. 図１８Ａは、ＣＴＳ－ｔｏ－ｓｅｌｆの場合のフレーム交換の他の例を示す図である。FIG. 18A is a diagram illustrating another example of frame exchange in the case of CTS-to-self. 図１８Ｂは、ＣＴＳ－ｔｏ－ｓｅｌｆの場合のフレーム交換の他の例を示す図である。FIG. 18B is a diagram illustrating another example of frame exchange in the case of CTS-to-self. 図１９Ａは、ＣＴＳ－ｔｏ－ｓｅｌｆの場合のフレーム交換の他の例を示す図である。FIG. 19A is a diagram illustrating another example of frame exchange in the case of CTS-to-self. 図１９Ｂは、ＣＴＳ－ｔｏ－ｓｅｌｆの場合のフレーム交換の他の例を示す図である。FIG. 19B is a diagram illustrating another example of frame exchange in the case of CTS-to-self. 図１９Ｃは、ＣＴＳ－ｔｏ－ｓｅｌｆの場合のフレーム交換の他の例を示す図である。FIG. 19C is a diagram illustrating another example of frame exchange in the case of CTS-to-self. 図２０Ａは、ＲＴＳ／ＣＴＳ交換やＣＴＳ－ｔｏ－ｓｅｌｆ送信をしない場合のフレーム交換の一例を示す図である。FIG. 20A is a diagram illustrating an example of frame exchange when RTS / CTS exchange or CTS-to-self transmission is not performed. 図２０Ｂは、ＲＴＳ／ＣＴＳ交換やＣＴＳ－ｔｏ－ｓｅｌｆ送信をしない場合のフレーム交換の一例を示す図である。FIG. 20B is a diagram illustrating an example of frame exchange when RTS / CTS exchange or CTS-to-self transmission is not performed. 図２０Ｃは、ＲＴＳ／ＣＴＳ交換やＣＴＳ－ｔｏ－ｓｅｌｆ送信をしない場合のフレーム交換の一例を示す図である。FIG. 20C is a diagram illustrating an example of frame exchange when RTS / CTS exchange or CTS-to-self transmission is not performed. 図２０Ｄは、ＲＴＳ／ＣＴＳ交換やＣＴＳ－ｔｏ－ｓｅｌｆ送信をしない場合のフレーム交換の一例を示す図である。FIG. 20D is a diagram illustrating an example of frame exchange when RTS / CTS exchange or CTS-to-self transmission is not performed. 図２１Ａは、データをバースト伝送する場合のフレーム交換の一例を示す図である。FIG. 21A is a diagram showing an example of frame exchange in the case of burst transmission of data. 図２１Ｂは、データをバースト伝送する場合のフレーム交換の一例を示す図である。FIG. 21B is a diagram showing an example of frame exchange in the case of burst transmission of data. 図２１Ｃは、データをバースト伝送する場合のフレーム交換の一例を示す図である。FIG. 21C is a diagram showing an example of frame exchange in the case of burst transmission of data. 図２１Ｄは、データをバースト伝送する場合のフレーム交換の一例を示す図である。FIG. 21D is a diagram showing an example of frame exchange in the case of burst transmission of data. 図２２は、第２の実施形態における物理ヘッダの構成例を示す図である。FIG. 22 is a diagram showing a configuration example of a physical header in the second embodiment. 図２３は、第２の実施形態に係る無線通信装置の送信制御処理の手順を示すフローチャートである。FIG. 23 is a flowchart illustrating the procedure of transmission control processing of the wireless communication apparatus according to the second embodiment. 図２４Ａは、Ｄａｔａ送信時のビームの指向性が適切でない場合の例を示す図である。FIG. 24A is a diagram illustrating an example in the case where the directivity of a beam at the time of Data transmission is not appropriate. 図２４Ｂは、Ｄａｔａ送信時のビームの指向性が適切でない場合の例を示す図である。FIG. 24B is a diagram showing an example in the case where the directivity of the beam at the time of Data transmission is not appropriate. 図２５Ａは、第３の実施形態に係る無線通信装置の構成例を示すブロック図である。FIG. 25A is a block diagram illustrating a configuration example of a wireless communication device according to a third embodiment. 図２５Ｂは、第３の実施形態に係る無線通信装置の他の構成例を示すブロック図である。FIG. 25B is a block diagram illustrating another configuration example of the wireless communication device according to the third embodiment. 図２６は、第３の実施形態における物理ヘッダの構成例を示す図である。FIG. 26 is a diagram showing a configuration example of a physical header in the third embodiment. 図２７は、第３の実施形態に係る無線通信装置の受信動作を示すフローチャートであるである。FIG. 27 is a flowchart showing the reception operation of the wireless communication apparatus according to the third embodiment. 図２８は、宛先アドレスが自局宛てでない場合の処理を示す図である。FIG. 28 is a diagram showing processing when the destination address is not addressed to the own station. 図２９Ａは、チャネル推定信号を送信する動作を示す図である。FIG. 29A is a diagram showing an operation of transmitting a channel estimation signal. 図２９Ｂは、チャネル推定信号を送信する動作を示す図である。FIG. 29B is a diagram illustrating an operation of transmitting a channel estimation signal. 図３０Ａは、ビーム制御信号を送信する動作を示す図である。FIG. 30A is a diagram showing an operation of transmitting a beam control signal. 図３０Ｂは、ビーム制御信号を送信する動作を示す図である。FIG. 30B is a diagram showing an operation of transmitting a beam control signal. 図３１は、第４の実施形態に係る無線通信装置が構成するネットワーク構成例を示す図である。FIG. 31 is a diagram illustrating an example of a network configuration configured by the wireless communication device according to the fourth embodiment. 図３２は、第４の実施形態における物理ヘッダの構成例を示す図である。FIG. 32 is a diagram showing an example of the configuration of a physical header in the fourth embodiment. 図３３は、第４の実施形態に係る無線通信装置の受信動作を示すフローチャートである。FIG. 33 is a flowchart showing the reception operation of the wireless communication apparatus according to the fourth embodiment. 図３４Ａは、第４の実施形態に係る無線通信装置のフレーム交換の一例を示す図である。FIG. 34A is a diagram illustrating an example of frame exchange of the wireless communication device according to the fourth embodiment. 図３４Ｂは、第４の実施形態に係る無線通信装置のフレーム交換の一例を示す図である。FIG. 34B is a diagram illustrating an example of frame exchange of the wireless communication device according to the fourth embodiment. 図３５は、物理ヘッダの構成の他の例を示す図である。FIG. 35 is a diagram showing another example of the configuration of the physical header. 図３６は、無線通信装置の他の構成例を示すブロック図である。FIG. 36 is a block diagram showing another configuration example of the wireless communication apparatus.
　以下、図面を参照しながら本発明の実施の形態を詳細に説明する。　
　（第１の実施形態）　
　図１は、本発明の第１の実施形態に係る無線通信装置の構成を示すブロック図である。無線通信装置１は、アンテナ部１１と、送受信部１２と、送信フレーム生成部１３と、受信フレーム解析部１４とを備える。送受信部１２は、ＲＦユニット１２１と、ビーム形成部１２２、制御部１２３とを有する。 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First Embodiment
FIG. 1 is a block diagram showing the configuration of a wireless communication apparatus according to the first embodiment of the present invention. The wireless communication device 1 includes an antenna unit 11, a transmission / reception unit 12, a transmission frame generation unit 13, and a reception frame analysis unit 14. The transmission / reception unit 12 includes an RF unit 121, a beam forming unit 122, and a control unit 123.
　アンテナ部１１は、複数のアンテナ素子を備えるアダプティブ・アレイ・アンテナで構成される。送受信部１２は、送信フレーム生成部１３で生成された送信フレームをビーム形成部１２２及びＲＦユニット１２１を介してＲＦ信号に変換してアンテナ部１１から送信する。また、送受信部１２は、アンテナ部１１に到来したＲＦ信号をＲＦユニット１２１及びビーム形成部１２２を介して受信信号に変換し、受信信号に含まれるフレームデータを受信フレーム解析部１４に供給する。 The antenna unit 11 is configured by an adaptive array antenna including a plurality of antenna elements. The transmission / reception unit 12 converts the transmission frame generated by the transmission frame generation unit 13 into an RF signal via the beam forming unit 122 and the RF unit 121, and transmits the RF signal from the antenna unit 11. In addition, the transmission / reception unit 12 converts the RF signal arriving at the antenna unit 11 into a reception signal via the RF unit 121 and the beam forming unit 122, and supplies frame data included in the reception signal to the reception frame analysis unit 14.
　ビーム形成部１２２は、制御部１２３による指向性制御にしたがって、アンテナ部１１により方向の異なる複数の指向性ビームを切り替えて形成する。図２に、この無線通信装置１が形成する指向性ビームの一例を示す。図２の例では、４方向の指向性ビーム１～４を切り替えて送信しているため、指向性ビーム１～４の通信エリアの和が、この無線通信装置１の通信エリアになる。以下、このようなビーム制御方式を指向性反復伝送（第１のモード）と称する。これに対し、ある特定の方向のみ、例えば、通信相手先の方向にのみ指向性ビームを形成する伝送方式を非反復伝送（第２のモード）と称する。 The beam forming unit 122 switches and forms a plurality of directional beams different in direction by the antenna unit 11 in accordance with directivity control by the control unit 123. FIG. 2 shows an example of a directional beam formed by the wireless communication device 1. In the example of FIG. 2, since directional beams 1 to 4 in four directions are switched and transmitted, the sum of the communication areas of the directional beams 1 to 4 becomes the communication area of the wireless communication device 1. Hereinafter, such a beam control scheme is referred to as directional repetitive transmission (first mode). On the other hand, a transmission scheme in which directional beams are formed only in a specific direction, for example, in the direction of the communication partner is referred to as non-repetitive transmission (second mode).
　図３は、送信フレーム生成部１３が生成する送信フレームのフォーマットの一例である。図３の例では、送信フレームは、信号同期用のプリアンブルと、物理ヘッダと、物理ヘッダのフレームチェックシーケンス（ＦＣＳ１）と、ＭＡＣヘッダと、ペイロードと、ＭＡＣヘッダ及びペイロードのフレームチェックシーケンス（ＦＣＳ２）とから構成される。ＦＣＳ１は、ヘッダに対するチェックシ－ケンスであることから、Ｈｅａｄｅｒ　Ｅｒｒｏｒ　Ｃｈｅｃｋ（ＨＥＣ）と呼ぶこともある。 FIG. 3 is an example of the format of a transmission frame generated by the transmission frame generation unit 13. In the example of FIG. 3, the transmission frame is a preamble for signal synchronization, a physical header, a frame check sequence of the physical header (FCS1), a MAC header, a payload, a MAC header and a frame check sequence of the payload (FCS2) And consists of Since FCS1 is a check sequence for the header, it may be called Header Error Check (HEC).
　図４に、従来の物理ヘッダのフォーマットの一例を示す。物理ヘッダには、パケット長と、後続するＭＡＣヘッダ、ペイロード、ＦＣＳ２が伝送される伝送レートに係わる情報が含まれている。パケット長は、ビット長で表記しても、時間長で表記することもできる。伝送レートの情報を利用すれば、ビット長を時間長に変換できるし、時間長をビット長に変換することができる。 FIG. 4 shows an example of a conventional physical header format. The physical header contains information on the packet length, the subsequent MAC header, the payload, and the transmission rate at which the FCS 2 is transmitted. The packet length can be expressed in bit length or in time length. By using the information of the transmission rate, the bit length can be converted to a time length, and the time length can be converted to a bit length.
　一般的に、物理ヘッダよりペイロードの方がデータ長が大きいため、ＦＣＳ１よりも、ＦＣＳ２の方が誤り検出性能の高い符号が必要とされる。そのため、ＦＣＳ１よりＦＣＳ２の方が多くのビット数が必要となる。また、物理ヘッダにおいて誤りの誤検出や検出見逃しがあっても、それはスループットや効率といった通信特性に対する影響であるが、ＭＡＣヘッダやペイロードの検出見逃しは誤動作につながりかねない。そのため、ＦＣＳ１よりもＦＣＳ２の方が誤り検出能力の高い符号が使われる。 In general, since the data length of the payload is larger than that of the physical header, a code having higher error detection performance is required for FCS2 than for FCS1. Therefore, FCS2 requires more bits than FCS1. In addition, even if an error is detected or missed in the physical header, it is an influence on communication characteristics such as throughput and efficiency, but missed detection of the MAC header or payload may lead to a malfunction. Therefore, a code with higher error detection capability is used in FCS2 than in FCS1.
　また、プリアンブルは同期をとるための信号を含むとしているが、それ以外にも、無線チャネルの状態を推定するためのチャネル推定フィールドや、あとに続く物理ヘッダの伝送レート情報を設ける方法なども考えられる。物理ヘッダの伝送レートが予め固定の場合は、必ずしもプリアンブルに伝送レート情報を含める必要はない。 Also, although it is assumed that the preamble includes a signal for achieving synchronization, other than that, a method of providing a channel estimation field for estimating the state of the wireless channel and transmission rate information of a subsequent physical header, etc. is also considered. Be When the transmission rate of the physical header is previously fixed, the preamble does not necessarily have to include the transmission rate information.
　以下、図３に示したように、プリアンブル、物理ヘッダ、物理ヘッダのフレームチェックシーケンスを第１のフィールドと定義し、ＭＡＣヘッダ、ペイロード、ＭＡＣヘッダ及びペイロードのフレームチェックシーケンス（ＦＣＳ２）を第２のフィールドと定義する。 Hereinafter, as shown in FIG. 3, the frame check sequence of the preamble, the physical header and the physical header is defined as a first field, and the MAC header, the payload, the MAC header and the frame check sequence of the payload (FCS2) is a second field. Define as a field.
　図５に、無線通信装置１が構成するネットワーク構成例を示す。図５では、無線通信装置１が、基地局（アクセス・ポイント）や端末局（ステーション）としてそれぞれ動作することにより構成されるネットワーク例を示している。端末局ＳＴＡ１、ＳＴＡ２は、基地局ＡＰを介して、ネットワークと接続する。 FIG. 5 shows an example of the network configuration configured by the wireless communication device 1. FIG. 5 illustrates an example of a network configured by the wireless communication device 1 operating as a base station (access point) or a terminal station (station). The terminal stations STA1 and STA2 connect to the network via the base station AP.
　図６は、従来の指向性反復伝送した例を示したものである。図６の例では、４種類の指向性ビームを用いた送信が必要な場合は、送信フレームを無線送信する際のある単位の無線信号を定義し、その無線信号の単位を、順次指向性ビームを切り替えながら、４回繰り返して送信する。ＯＦＤＭ伝送の場合に、１シンボルを単位とすれば、同じシンボルを指向性ビームを切り替えながら４回ずつ繰り返し送信することである。例えば、プリアンブルが８つのシンボルから構成される場合は、１つ目のシンボルを４回送信し、その後、２つ目のシンボルを４回送信する処理を行っていく。同じシンボルをビームの指向性を切り替えながら、繰り返し送信しているため、広範囲の無線通信装置がこのフレームを受信できるようになる。ただし、繰り返し送信した数だけ伝送効率は劣化してしまうという問題があった。 FIG. 6 shows an example of conventional directional repetitive transmission. In the example of FIG. 6, when it is necessary to transmit using four types of directional beams, a certain unit of radio signal in wireless transmission of a transmission frame is defined, and the units of the radio signal are sequentially directed beam Repeat sending 4 times while switching. In the case of OFDM transmission, if one symbol is used as a unit, the same symbol is repeatedly transmitted four times while switching the directional beam. For example, when the preamble is composed of eight symbols, the first symbol is transmitted four times, and then the second symbol is transmitted four times. Since the same symbol is repeatedly transmitted while switching the directivity of the beam, a wide range of wireless communication devices can receive this frame. However, there is a problem that the transmission efficiency is degraded by the number of repeated transmissions.
　図７Ａに、ＩＥＥＥ８０２.１１無線ＬＡＮで定義されている代表的なフレーム交換(ＲＴＳ－ＣＴＳ－Ｄａｔａ－Ａｃｋ)を示す。送信しようとする端末局は、宛先に向けてＲＴＳ（Request to Send：送信要求）を送信し、このＲＴＳに応じて宛先から送信されるＣＴＳ（Clear to Send：受信準備完了）を受信した後に、データを送信するものである。図７Ｂには、このフレーム交換に図６に示した指向性反復伝送を適用した場合の例を示す。図７Ｂでは、各フレームの送信時間長は４倍になってしまうため、図７Ａ，７Ｂからも明らかなように、指向性反復伝送を用いると、伝送効率が大幅に低下していることがわかる。 FIG. 7A shows a representative frame exchange (RTS-CTS-Data-Ack) defined in the IEEE 802.11 wireless LAN. The terminal station to be sent sends an RTS (Request to Send) to the destination, and after receiving a CTS (Clear to Send: ready to receive) sent from the destination according to the RTS, It sends data. FIG. 7B shows an example in the case where the directional repetitive transmission shown in FIG. 6 is applied to this frame exchange. In FIG. 7B, since the transmission time length of each frame is quadrupled, it is understood that transmission efficiency is significantly reduced when directional repetitive transmission is used, as is apparent from FIGS. 7A and 7B. .
　一方、上記図２に示したように、指向性反復伝送の場合、この無線通信装置の通信エリアは指向性ビーム１～４の通信エリアの和となる。また、通信相手が、指向性ビーム１～４のいずれかに位置している場合は、他の通信エリアに位置する端末に対しては、通信中であることを示すことができるため、隠れ端末問題による無駄な無線信号の衝突を回避することができる。隠れ端末問題を回避するためには、図７Ｂに示したように無線信号を各通信エリアに常に送信して、チャネルがｂｕｓｙであることを示す方法もあれば、無線信号の中に、チャネルを使用する期間情報（チャネル予定期間）を含め、その期間情報を用いてチャネルを予約する方法もある。 On the other hand, as shown in FIG. 2, in the case of directional repetitive transmission, the communication area of this wireless communication apparatus is the sum of the communication areas of directional beams 1 to 4. In addition, when the other party of communication is located in any of directional beams 1 to 4, it is possible to indicate to other terminals located in the other communication area that communication is in progress, so the hidden terminal It is possible to avoid unnecessary radio signal collisions due to problems. In order to avoid the hidden terminal problem, as shown in FIG. 7B, there is a method of always transmitting a wireless signal to each communication area to indicate that the channel is busy. There is also a method of reserving a channel using the period information including the period information (channel scheduled period) to be used.
　このチャネルを予約する方法を用いると、例えば図８Ａ，８Ｂのように、ＲＴＳ及びＣＴＳフレームのみ指向性反復伝送で送信し、あとに続くフレーム（Ｄａｔａ，Ａｃｋ）は通常の伝送方式（非反復伝送）で送信することもできる。この方法は、ＲＴＳ及びＣＴＳフレームを用いて周囲の無線通信装置に、これからチャネルを使用することを通知し、その後のＤａｔａとＡｃｋの送信は、通信相手が位置する通信エリアのみをカバーする指向性ビームを用いて送信する方法である。この方法を用いると、図７Ｂよりも伝送効率を向上させることができる。同様に、図８Ｃ，８Ｄに示すように基地局が送信するＲＴＳ又はＣＴＳフレームのみ、指向性反復伝送方式を用いて、基地局の通信エリアに位置する無線通信装置にチャネルの予約情報を通知する方法もある。図８Ｃ，８Ｄの方法を用いれば、図８Ａ，８Ｂよりは、通信効率を向上させることができるが、ＲＴＳやＣＴＳを指向性反復伝送で伝送することにより、伝送効率が低下していることには変わらない。 For example, as shown in FIGS. 8A and 8B, when this channel reservation method is used, only RTS and CTS frames are transmitted by directional repetitive transmission, and the subsequent frames (Data, Ack) are transmitted using the normal transmission method (non-repetitive transmission). It can also be sent by). This method uses RTS and CTS frames to notify surrounding wireless communication devices to use a channel from now on, and the subsequent transmission of Data and Ack is directivity that covers only the communication area in which the communication partner is located. It is a method of transmitting using a beam. By using this method, transmission efficiency can be improved more than in FIG. 7B. Similarly, as shown in FIGS. 8C and 8D, only RTS or CTS frames transmitted by the base station notify channel reservation information to a wireless communication apparatus located in the communication area of the base station using the directional repetitive transmission scheme. There is also a way. Although the communication efficiency can be improved by using the methods of FIGS. 8C and 8D as compared with FIGS. 8A and 8B, the transmission efficiency is lowered by transmitting RTS and CTS by directional repetitive transmission. Does not change.
　この第１の実施形態では、伝送効率をさらに向上することが可能な手法を説明する。　
　図９に、第１の実施形態における物理ヘッダの構成例を示す。図９は、上記図４の物理ヘッダに、チャネルの予約期間（ＰＨＹ ｄｕｒａｔｉｏｎ（ＮＡＶ：Network Allocation Vector、通信予定期間））を付加したものである。このＰＨＹ Ｄｕｒａｔｉｏｎは、このパケット自体のパケット長（length）ではなく、これ以降に続く予定のフレーム交換期間に関する情報である。 In the first embodiment, a method capable of further improving transmission efficiency will be described.
FIG. 9 shows a configuration example of the physical header in the first embodiment. FIG. 9 shows the physical header of FIG. 4 added with a channel reservation period (PHY duration (NAV: Network Allocation Vector, communication scheduled period)). This PHY Duration is not the packet length (length) of this packet itself, but is information on a frame exchange period scheduled to follow thereafter.
　図１０は、送信フレーム生成処理の手順を示すフローチャートである。　
　先ず、送信フレーム生成部１３は、信号同期用のプリアンブルを生成する（ステップＳ１ａ）。次に、物理ヘッダに付加するためのチャネル予定期間を算出する（ステップＳ２ａ）。チャネル予定期間の算出方法は後述する。送信フレーム生成部１３は、上記算出されたチャネル予定期間を付加した物理ヘッダを生成し（ステップＳ３ａ）、物理ヘッダ用のフレームチェックシーケンス（ＦＣＳ１）を生成する（ステップＳ４ａ）。こうして、プリアンブル、物理ヘッダ、物理ヘッダ用のフレームチェックシーケンス（ＦＣＳ１）を含む第１のフィールドが生成される。そして、送信フレーム生成部１３は、第１のフィールドに後続する、ＭＡＣアドレス及びペイロードを生成し（ステップＳ５ａ）、ＭＡＣアドレス及びペイロード用のフレームチェックシーケンス（ＦＣＳ２）を生成する（ステップＳ６ａ）。こうして、ＭＡＣアドレス、ペイロード、ＭＡＣアドレス及びペイロード用のフレームチェックシーケンス（ＦＣＳ２）を含む第２のフィールドが生成される。 FIG. 10 is a flowchart showing the procedure of transmission frame generation processing.
First, the transmission frame generation unit 13 generates a preamble for signal synchronization (step S1a). Next, a channel scheduled period to be added to the physical header is calculated (step S2a). The calculation method of the channel scheduled period will be described later. The transmission frame generation unit 13 generates a physical header to which the calculated channel scheduled period is added (step S3a), and generates a frame check sequence (FCS1) for the physical header (step S4a). Thus, a first field including a preamble, a physical header, and a frame check sequence (FCS1) for the physical header is generated. Then, the transmission frame generation unit 13 generates a MAC address and a payload following the first field (step S5a), and generates a frame check sequence (FCS2) for the MAC address and the payload (step S6a). Thus, a second field including the MAC address, the payload, the MAC address, and the frame check sequence (FCS2) for the payload is generated.
　図１１に、上記生成された送信フレームを送信する時のビーム制御方法を示す。　
　送受信部１は、送信フレームのうち、プリアンブル、物理ヘッダ及び物理ヘッダ用のフレームチェックシーケンス（ＦＣＳ１）を含む第１のフィールドを指向性反復伝送で送信する。すなわち、制御部１２３はビーム形成部１２２により方向の異なる複数の指向性ビームを切り替えながら、第１のフィールド内の各シンボルを４回ずつ繰り返し送信する。 FIG. 11 shows a beam control method when transmitting the generated transmission frame.
The transmission / reception unit 1 transmits, in the transmission frame, a first field including a preamble, a physical header, and a frame check sequence (FCS1) for the physical header by directional repetitive transmission. That is, the control unit 123 repeatedly transmits each symbol in the first field four times while switching a plurality of directional beams in different directions by the beam forming unit 122.
　一方、第１のフィールドに後続するＭＡＣアドレス、ペイロード、ＭＡＣアドレス及びペイロード用のフレームチェックシーケンス（ＦＣＳ２）を含む第２のフィールドは、非反復伝送で送信される。制御部１２３は、ビーム形成部１２２によりＭＡＣアドレスに含まれる宛先の方向に指向性ビームを形成して第２のフィールドを送信する。 On the other hand, the second field including the MAC address following the first field, the payload, the MAC address, and the frame check sequence (FCS2) for the payload is transmitted by non-repetitive transmission. The control unit 123 causes the beam forming unit 122 to form a directional beam in the direction of the destination included in the MAC address and transmits the second field.
　このように送信することで、スループットを低減することなく、広範囲の無線局に対して、チャネル予定期間を通知することが可能になる。 By transmitting in this manner, it is possible to notify a channel scheduled period to a wide range of radio stations without reducing the throughput.
　図１２は、図９に示した物理ヘッダを含むフレームを受信した場合の受信動作の手順を示すフローチャートである。　
　受信フレーム解析部１４は、第１のフィールドを受信すると（ステップＳ１ｂ）、物理ヘッダに含まれるチャネル予定期間を取得する（ステップＳ２ｂ）。さらに第２のフィールドを受信した場合は（ステップＳ３ｂ）、受信した第２のフィールドからＭＡＣヘッダを取得する（ステップＳ４ｂ）。取得したＭＡＣヘッダに含まれる宛先アドレスが自局宛てである場合は（ステップＳ５ｂ）、送受信部１２はその後の送受信処理を行う（ステップＳ６ｂ）。一方、ステップＳ３ｂにおいて第２のフィールドが受信できなかった場合、又は、ステップＳ５ｂにおいて宛先アドレスが自局宛てでない場合は、受信フレーム解析部１４は制御部１２３に通知することで、送受信部１２はチャネル予定期間の送信を禁止する（ステップＳ７ｂ）。 FIG. 12 is a flowchart showing the procedure of the receiving operation when the frame including the physical header shown in FIG. 9 is received.
When the reception frame analysis unit 14 receives the first field (step S1 b), the reception frame analysis unit 14 acquires a channel scheduled period included in the physical header (step S2 b). When the second field is further received (step S3b), the MAC header is acquired from the received second field (step S4b). If the destination address included in the acquired MAC header is addressed to the local station (step S5b), the transmission / reception unit 12 performs the subsequent transmission / reception process (step S6b). On the other hand, if the second field can not be received in step S3b, or if the destination address is not addressed to the own station in step S5b, the reception frame analysis unit 14 notifies the control unit 123 so that the transmission / reception unit 12 can The transmission of the channel scheduled period is prohibited (step S7b).
　ここで、図１３Ａ，１３Ｂを参照して、チャネル予定期間について説明する。物理ヘッダに付加するチャネル予定期間の開始は、第１のフィールドの送信終了直後とする。すなわち、第２のフィールドの送信が開始される予定時刻とする。また、ＭＡＣヘッダにもチャネル予定期間を付加する場合は、第２のフィールドの送信完了時刻をチャネル予定期間の開始時刻とする。つまり、物理ヘッダの付加するチャネル予定期間の開始時刻と、ＭＡＣヘッダに付加するチャネル予定期間の開始時刻は、異なるものとする。但し、チャネル予定期間の終了時刻は同じで、フレーム交換の終了時刻とする。 Here, the channel scheduled period will be described with reference to FIGS. 13A and 13B. The start of the channel scheduled period to be added to the physical header is immediately after the end of the transmission of the first field. That is, it is set as the scheduled time when transmission of the second field is started. Also, when adding a channel scheduled period to the MAC header, the transmission completion time of the second field is set as the start time of the channel scheduled period. That is, it is assumed that the start time of the scheduled channel period to which the physical header is added and the start time of the scheduled channel period to be added to the MAC header are different. However, the end time of the channel scheduled period is the same, and is the end time of the frame exchange.
　例えば、図１３ＡのＲＴＳの物理ヘッダに含まれるチャネル予定期間を５００［ｕｓ］とし、ＲＴＳの第２のフィールドのフレーム長を３０［ｕｓ］とする。この時、ＲＴＳのＭＡＣヘッダに含まれるチャネル予定期間は、４７０(＝５００－３０)［ｕｓ］とする。これにより、図１３Ａのフレーム交換を受信した第３者の無線通信装置において、ＲＴＳは受信できたがＣＴＳを受信できなかった無線局と、ＲＴＳは受信できなかったがＣＴＳを受信できた無線局とが認識するチャネル予定期間を同じ値にすることができる。また、Ｄａｔａ送信時の物理ヘッダに記載するチャネル予定期間を算出する際に、受信したＣＴＳのＭＡＣフレームに含まれるチャネル予定期間に基づいて算出することができる。 For example, the channel scheduled period included in the physical header of RTS in FIG. 13A is 500 [us], and the frame length of the second field of RTS is 30 [us]. At this time, the channel scheduled period included in the RTS MAC header is 470 (= 500-30) [us]. As a result, in the third party's wireless communication apparatus that has received the frame exchange in FIG. 13A, the wireless station that could receive RTS but could not receive CTS and the wireless station that could not receive RTS but could receive CTS. The channel scheduled period recognized by can be made the same value. Further, when calculating the channel scheduled period described in the physical header at the time of Data transmission, it can be calculated based on the channel scheduled period included in the received CTS MAC frame.
　また、図１３ＢのようなＣＴＳ－Ｄａｔａ－Ａｃｋのフレーム交換の場合も同様にチャネル予定期間を算出して設定するようにする。 Also, in the case of frame exchange of CTS-Data-Ack as shown in FIG. 13B, the channel scheduled period is similarly calculated and set.
　図１４Ａ，１４Ｂに第１の実施形態におけるフレーム交換の一例を示す。図１４Ａは、基地局側のＲＴＳフレームの第１のフィールドのみを指向性反復伝送方式で伝送し、ＲＴＳの第２フィールド以降は宛先の方向の指向性ビームを用いて非反復伝送するものである。これにより、前述の図８Ｃと同様の効果を得つつ、さらに通信効率を向上させることができる。図１４Ｂは、基地局側のＣＴＳフレームの第１のフィールドのみを指向性反復伝送方式で伝送し、ＣＴＳ第２フィールド以降は宛先の方向の指向性ビームを用いて非反復伝送するものである。このようにすると、前述の図８Ｄと同様の効果を得つつ、さらに通信効率を向上させることができる。 14A and 14B show an example of frame exchange in the first embodiment. In FIG. 14A, only the first field of the RTS frame on the base station side is transmitted by the directional repetitive transmission scheme, and non-repetitive transmission is performed using the directional beam of the direction of the destination after the second field of the RTS. . Thus, the communication efficiency can be further improved while obtaining the same effect as that of FIG. 8C described above. In FIG. 14B, only the first field of the CTS frame on the base station side is transmitted by the directional repetitive transmission scheme, and non-repetitive transmission is performed using the directional beam in the direction of the destination after the CTS second field. In this way, it is possible to further improve the communication efficiency while obtaining the same effect as that of FIG. 8D described above.
　また、図１５Ａ～１５Ｄに第１の実施形態におけるフレーム交換の他の例を示す。図１５Ａ，１５Ｂは、ＲＴＳ及びＣＴＳフレームの第１フィールドのみを指向性反復伝送方式で伝送し、ＲＴＳ及びＣＴＳフレームの第２フィールド以降は宛先の方向の指向性ビームを用いて非反復伝送するものである。これにより、前述の図８Ａ，８Ｂと同様の効果を得つつ、通信効率を向上させることができる。 Further, FIGS. 15A to 15D show another example of frame exchange in the first embodiment. FIGS. 15A and 15B transmit only the first field of the RTS and CTS frame by the directional repetitive transmission method, and transmit non-repetitively using the directional beam of the direction of the destination after the second field of the RTS and CTS frame It is. As a result, communication efficiency can be improved while obtaining the same effects as those of FIGS. 8A and 8B described above.
　また、上記指向性反復伝送方式では、チャネルが使用されているか否かを確認するために必要な情報のみを繰り返し送信しているため、通信効率が良い。そこで、図１５Ｃ，１５Ｄに示すように、ＲＴＳ／ＣＴＳ交換に続く、Ｄａｔａ及びＡｃｋフレームの第１フィールドも指向性反復伝送方式で伝送するようにしてもよい。これにより、ＲＴＳ又はＣＴＳフレームに含まれる物理ヘッダの受信に失敗した場合であっても、Ｄａｔａ又はＡｃｋフレームの物理ヘッダを受信することができれば、チャネル予定期間が把握できるため、隠れ端末問題解消の信頼性を向上させることができる。特に、Ｄａｔａ及びＡｃｋフレームを連続してバースト伝送するような場合に効果的である。 Further, in the directional repetitive transmission method, only information necessary to confirm whether a channel is being used is repeatedly transmitted, so that communication efficiency is good. Therefore, as shown in FIGS. 15C and 15D, the first fields of the Data and Ack frames following RTS / CTS exchange may also be transmitted by the directional repetitive transmission method. As a result, even if reception of the physical header included in the RTS or CTS frame fails, if the physical header of the Data or Ack frame can be received, the channel scheduled period can be grasped, so that the hidden terminal problem can be solved. Reliability can be improved. In particular, it is effective in the case where data and Ack frames are continuously burst transmitted.
　さらに、図１６Ａ～１６Ｃにフレーム交換の他の例を示す。図１５Ａから１５Ｄの応用として、図１６Ａ，１６Ｃのように、基地局が送信するフレームの第１のフィールドのみを指向性反復伝送方式で伝送しても良い。これにより、基地局の通信エリア内にいる端末局に対してチャネル予定期間に関する情報などを効率よく通知することができる。 Furthermore, FIGS. 16A to 16C show other examples of frame exchange. As an application of FIGS. 15A to 15D, as shown in FIGS. 16A and 16C, only the first field of the frame transmitted by the base station may be transmitted by the directional repetitive transmission scheme. As a result, it is possible to efficiently notify the terminal station in the communication area of the base station of the information on the scheduled channel period and the like.
　図１６Ｄに、このような場合における制御部１２３の送信制御処理の手順を示すフローチャートを示す。　
　制御部１２３は、装置種別を表す情報（基地局／端末局）に応じて第１のフィールドの送信方式を選択する（ステップＳ１）。例えば、装置種別が基地局の場合は指向性反復伝送方式を選択し、装置種別が端末局の場合は非反復伝送方式を選択するものとする。制御部１２３は、ステップＳ１で指向性反復伝送方式と選択すると（ステップＳ２）、第１のフィールドを指向性反復伝送方式で送信し（ステップＳ３）、第２のフィールドを非反復伝送方式で送信する（ステップＳ４）。一方、制御部１２３は、ステップＳ１で非反復伝送方式を選択すると、第１のフィールド及び第２のフィールドを非反復伝送方式で送信する（ステップＳ４、Ｓ５）。 FIG. 16D is a flowchart showing the procedure of the transmission control process of the control unit 123 in such a case.
The control unit 123 selects the transmission method of the first field according to the information (base station / terminal station) indicating the device type (step S1). For example, when the device type is a base station, the directional repetitive transmission method is selected, and when the device type is a terminal station, the non-repetitive transmission method is selected. When the control unit 123 selects the directional repetitive transmission scheme in step S1 (step S2), the control unit 123 transmits the first field in the directional repetitive transmission scheme (step S3), and transmits the second field in the non-repetitive transmission scheme. (Step S4). On the other hand, when the non-repetitive transmission scheme is selected in step S1, the control unit 123 transmits the first field and the second field in the non-repetitive transmission scheme (steps S4 and S5).
　また、図１６Ｂのように、端末局が、チャネルを獲得するために最初に送信するＲＴＳの１のフィールドのみを指向性反復伝送方式で送信してもよい。これにより、ＲＴＳを送信する端末局の周辺に位置する他の端末局に対して、いち早く、チャネル予定期間に関する情報を通知することができる。 Also, as shown in FIG. 16B, the terminal station may transmit only one field of RTS to be transmitted first to acquire a channel in a directional repetitive transmission scheme. As a result, it is possible to quickly notify other terminal stations located in the vicinity of the terminal station that transmits the RTS, of the information regarding the channel scheduled period.
　なお、通常のＲＴＳ／ＣＴＳ手順では、無線通信装置１は自局宛てのＲＴＳ信号を受信したことをトリガにＣＴＳ信号を送信するが、自局宛てのＲＴＳを受けなくても送信できるＣＴＳ信号を定義してもよい。すなわち自局宛てのＣＴＳ信号であることから、「ＣＴＳ－ｔｏ－ｓｅｌｆ」とも呼ぶ。 In the normal RTS / CTS procedure, although the wireless communication device 1 transmits a CTS signal triggered by the reception of the RTS signal addressed to the local station, the CTS signal can be transmitted without receiving the RTS addressed to the local station. It may be defined. That is, it is also called "CTS-to-self" because it is a CTS signal addressed to the own station.
　図１７Ａ，１７ＢにＣＴＳ－ｔｏ－ｓｅｌｆの場合のフレーム交換の一例を示す。図１７Ａは、ＣＴＳ－ｔｏ－ｓｅｌｆで基地局から端末局へ送信する場合、図１７ＢはＣＴＳ－ｔｏ－ｓｅｌｆで端末局から基地局へ送信する場合を示す。図１７Ａは、基地局から送信するＣＴＳフレームの第１フィールドのみを指向性反復伝送方式で伝送するものである。図１７Ｂは、端末局から送信するＣＴＳフレームのプ第１フィールドのみを指向性反復伝送方式で伝送するものである。 17A and 17B show an example of frame exchange in the case of CTS-to-self. FIG. 17A shows the case of transmission from the base station to the terminal station by CTS-to-self, and FIG. 17B shows the case of transmission from the terminal station to the base station by CTS-to-self. FIG. 17A is to transmit only the first field of the CTS frame transmitted from the base station by the directional repetitive transmission method. In FIG. 17B, only the first field of the CTS frame transmitted from the terminal station is transmitted by the directional repetitive transmission method.
　図１８Ａ，１８ＢにＣＴＳ－ｔｏ－ｓｅｌｆの場合のフレーム交換の他の例を示す。図１８Ａは、ＣＴＳ－ｔｏ－ｓｅｌｆで基地局から端末局へ送信する場合、図１８ＢはＣＴＳ－ｔｏ－ｓｅｌｆで端末局から基地局へ送信する場合を示す。図１８Ａ，Ｂは、ＣＴＳ，Ｄａｔａ，Ａｃｋの各フレームの第１フィールドを指向性反復伝送方式で伝送するものである。 18A and 18B show another example of frame exchange in the case of CTS-to-self. FIG. 18A shows the case of transmission from the base station to the terminal station by CTS-to-self, and FIG. 18B shows the case of transmission from the terminal station to the base station by CTS-to-self. FIGS. 18A and 18B transmit the first field of each frame of CTS, Data and Ack by the directional repetitive transmission method.
　また、図１９Ａ，１９Ｂ，１９Ｃは、ＣＴＳ－ｔｏ－ｓｅｌｆの場合のフレーム交換の他の例を示したものである。図１９Ａは、基地局から送信するフレームの第１フィールドのみを指向性反復伝送方式で伝送する場合であり、図１９Ｂは、基地局から送信するフレームの第１フィールドと、端末局が送信する最初のＣＴＳフレームの第１フィールドを指向性反復伝送方式で伝送するものである。図１９Ｃは、基地局から最初に送信するフレームの第１フィールドのみを指向性反復伝送方式で伝送するものである。 19A, 19B and 19C show another example of frame exchange in the case of CTS-to-self. FIG. 19A shows the case where only the first field of the frame transmitted from the base station is transmitted by the directional repetitive transmission method, and FIG. 19B shows the first field of the frame transmitted from the base station and the first transmission of the terminal station. The first field of the CTS frame is transmitted by the directional repetitive transmission method. FIG. 19C is to transmit only the first field of the frame to be transmitted first from the base station by the directional repetitive transmission scheme.
　図２０Ａ～２０Ｄは、ＲＴＳ／ＣＴＳ交換やＣＴＳ－ｔｏ－ｓｅｌｆ送信をしない場合のフレーム交換例を示したものである。図２０Ａ，２０Ｂは、基地局から端末局へデータ送信する場合で、図２０Ｃ，２０Ｄは、端末局から基地局へデータ送信する場合を示す。図２０Ａ，２０Ｃは、基地局及び端末局の双方からの送信フレームの第１のフィールドを指向性反復伝送方式で伝送し、図２０Ｂ，２０Ｄは、基地局からの送信フレームの第１のフィールドのみを指向性反復伝送方式で伝送するものである。 FIGS. 20A to 20D show an example of frame exchange when RTS / CTS exchange or CTS-to-self transmission is not performed. FIGS. 20A and 20B show data transmission from the base station to the terminal station, and FIGS. 20C and 20D show data transmission from the terminal station to the base station. 20A and 20C transmit the first field of the transmission frame from both the base station and the terminal station in the directional repetitive transmission scheme, and FIGS. 20B and 20D transmit only the first field of the transmission frame from the base station Are transmitted by the directional repetitive transmission method.
　図２１Ａ～２１Ｄに、データをバースト伝送する場合のフレーム交換例を示す。図２１Ａ，Ｃは、基地局から端末局へデータをバースト伝送する場合で、図２１Ｂ，Ｄは、端末局から基地局へデータをバースト伝送する場合を示している。図２１Ａ、２１Ｂは、基地局及び端末局の双方からの送信フレームの第１のフィールドを指向性反復伝送方式で伝送し、図２１Ｃ、２１Ｄは、基地局からの送信フレームの第１のフィールドのみを指向性反復伝送方式で伝送するものである。なお、図２１Ａ～２１Ｄには、ＲＴＳ/ＣＴＳや、ＣＴＳ－ｔｏ－ｓｅｌｆ等を送信せずにＤａｔａのみをバースト伝送する場合のフレーム交換例を示したが、Ｄａｔａバーストの前に、ＲＴＳ/ＣＴＳ交換やＣＴＳ－ｔｏ－ｓｅｌｆを送信する方法を用いても良い。 21A to 21D show an example of frame exchange in the case of burst transmission of data. 21A and 21C show burst transmission of data from the base station to the terminal station, and FIGS. 21B and 21D show burst transmission of data from the terminal station to the base station. 21A and 21B transmit the first field of the transmission frame from both the base station and the terminal station in the directional repetitive transmission scheme, and FIGS. 21C and 21D transmit only the first field of the transmission frame from the base station Are transmitted by the directional repetitive transmission method. 21A to 21D show an example of frame exchange in the case of burst transmission of only Data without transmitting RTS / CTS, CTS-to-self, etc. However, RTS / CTS is performed before Data burst. A method of exchanging or sending CTS-to-self may be used.
　（第２の実施形態）　
　第２の実施形態は、送信フレームのタイプ等に応じて指向性反復伝送方式と非反復伝送方式とを切り替えて送信する手法について説明する。第２の実施形態の構成は、上記図１の構成と同様のため、図１を用いて説明を行う。なお、第２の実施形態は、物理ヘッダの構成と、制御部１２３の動作が異なるものである。 Second Embodiment
In the second embodiment, a method will be described in which the directional repetitive transmission scheme and the non-repetitive transmission scheme are switched and transmitted according to the type of transmission frame and the like. The configuration of the second embodiment is the same as the configuration of FIG. 1 described above, and therefore will be described using FIG. In the second embodiment, the configuration of the physical header and the operation of the control unit 123 are different.
　図２２に、第２の実施形態における物理ヘッダの構成例を示す。図２２は、上記図９の物理ヘッダに、ビーム制御識別子に係わる情報を付加したものである。このビーム制御識別子は、第２フィールドをどのように送信するかを示すための識別子である。この識別子を使うことにより、第２フィールドを、１つの指向性ビームを用いて非反復伝送方式で送信する、もしくは、第１フィールドと同様に指向性反復伝送方式で送信するかを相手先に通知することができる。例えば、宛先アドレスがブロードキャストである場合は、自局と通信可能なすべての端末が受信できるように、ＭＡＣヘッダ以降も指向性反復伝送方式で送信し、宛先アドレスが特定の端末局である場合は、その端末局が受信できる方向の指向性ビームを用いて送信する。このように宛先アドレスがブロードキャストかユニキャストかによって、このビーム制御識別子に適切な値をセットする。なお、宛先アドレスがブロードキャストアドレスの場合は、常に指向性反復伝送方式で送信することを、予め決めておけば、ビーム制御識別子は無くてもよい。 FIG. 22 shows a configuration example of a physical header in the second embodiment. FIG. 22 shows the physical header of FIG. 9 added with information related to the beam control identifier. The beam control identifier is an identifier for indicating how to transmit the second field. By using this identifier, it is notified to the other party whether the second field is to be transmitted by non-repetitive transmission using one directional beam or to be transmitted by directional repetitive transmission as in the first field. can do. For example, if the destination address is a broadcast, it is transmitted by the directional repetitive transmission method after the MAC header so that all terminals capable of communicating with the local station can receive, and if the destination address is a specific terminal station , Transmit using a directional beam in a direction that the terminal station can receive. Thus, depending on whether the destination address is broadcast or unicast, this beam control identifier is set to an appropriate value. If the destination address is a broadcast address, the beam control identifier may not be necessary if it is determined in advance to always transmit in the directional repetitive transmission method.
　次に、制御部１２３の動作について説明する。図２３は、制御部１２３の送信制御処理の手順を示すフローチャートである。 Next, the operation of the control unit 123 will be described. FIG. 23 is a flowchart of the transmission control process of the control unit 123.
　制御部１２３は、送信フレーム生成部１３から送信フレームのフレームタイプ情報が通知されると、このフレームタイプ情報に応じて第１のフィールドの送信方式を選択する（ステップＳ１ｃ）。例えば、フレームタイプ情報がＲＴＳフレームの場合は、指向性反復伝送方式を選択する等とする。制御部１２３は、ステップＳ１ｃで指向性反復伝送方式と選択すると（ステップＳ２ｃ）、第１のフィールドを指向性反復伝送方式で送信する（ステップＳ３ｃ）。 When notified of the frame type information of the transmission frame from the transmission frame generation unit 13, the control unit 123 selects the transmission method of the first field according to the frame type information (step S 1 c). For example, when the frame type information is an RTS frame, it is assumed that a directional repetition transmission scheme is selected. When the control unit 123 selects the directional repetitive transmission scheme in step S1c (step S2c), the control unit 123 transmits the first field in the directional repetitive transmission scheme (step S3c).
　次に、宛先アドレスがブロードキャストである場合（ステップＳ４ｃ）は、第２のフィールドを指向性反復伝送方式で送信する（ステップＳ４ｃ）。また、制御部１２３は、ステップＳ４ｃにおいて、宛先アドレスがユニキャストである場合には、第２のフィールドを非反復伝送方式で送信する（ステップＳ７ｃ）。一方、制御部１２３は、ステップＳ１ｃで非反復伝送方式を選択すると、第１のフィールド及び第２のフィールドを非反復伝送方式で送信する（ステップＳ６ｃ、Ｓ７ｃ）。 Next, when the destination address is a broadcast (step S4c), the second field is transmitted by the directional repetitive transmission method (step S4c). When the destination address is unicast in step S4c, the control unit 123 transmits the second field by the non-repetitive transmission method (step S7c). On the other hand, when the non-repetitive transmission scheme is selected in step S1c, the control unit 123 transmits the first field and the second field in the non-repetitive transmission scheme (steps S6c and S7c).
　また、端末局が移動するような場合は、指向性反復伝送を用いて全方向に対して送信する必要はないものの、移動する可能性のある方向を含めて複数の指向性ビームで送信した方が良い。そのため、例えば８種類の指向性を有するビームがある場合、第１のフィールドは、８回繰り返しの指向性反復伝送方式で送信し、第２のフィールドは、８種類の指向性ビームのうちの３つを用いて、３回繰り返しの指向性反復伝送方式で送信する。指向性反復伝送方式を用いる場合は、受信側は、その繰り返し回数を把握する必要があるが、本実施形態を用いれば、その繰り返し回数を、宛先アドレスや、通信相手の移動方向などを考慮して、適宜必要な回数を選択することが可能となる。 In addition, when the terminal station moves, it is not necessary to transmit in all directions using directional repetitive transmission, but it is preferable to transmit with multiple directional beams including directions that may move. Is good. Therefore, for example, when there are beams having eight types of directivity, the first field is transmitted by the eight-time directivity repetitive transmission scheme, and the second field is three of the eight types of directional beams. Transmission using a three-times directional repeat transmission scheme. When using the directional repeat transmission method, the receiving side needs to know the number of repetitions, but according to the present embodiment, the number of repetitions is determined in consideration of the destination address, the moving direction of the communication partner, etc. Therefore, it is possible to select the necessary number of times as appropriate.
　上記第１の実施形態では、第２のフィールドの送信方法を１つの指向性ビームを用いて伝送する例を用いて説明したが、ビーム制御識別子を用いれば、必要に応じて繰り返し回数を動的に適用することができる。 In the first embodiment, the transmission method of the second field is described using an example of transmission using one directional beam. However, if a beam control identifier is used, the number of repetitions can be dynamically changed as necessary. It can be applied to
　（第３の実施形態）　
　図２４Ａ，２４Ｂに、上記図９Ａ、９Ｂに示した指向性反復伝送を用いたフレーム交換において、Ｄａｔａ送信時のビームの指向性が適切でない場合の例を示す。図２４Ａのように、基地局ＡＰは、端末局ＳＴＡ宛て送信に適した指向性ビームを用いてＤａｔａを送信するが、無線通信環境の変化があると、指向性ビームが適切でなくなり、その結果、宛先の端末局ＳＴＡに対してＤａｔａが正しく伝送できないことがある。このような場合、基地局ＡＰは、指向性反復伝送方式などを用いて、Ｄａｔａの再送処理を行うが、この方法は、実際にＤａｔａ送信をしてみないと、指向性ビームが正しいか否かの判断ができない。また、Ｄａｔａ送信を高効率な多値変調方式で送信した場合は、指向性ビームが適切でないことによるＳＩＮＲ不足か、指向性ビームは適切であるにも関わらず、ＳＩＮＲが不足しているかの判断が難しい。前者の場合は、再送時には指向性ビームを変更することが望ましく、後者の場合は、再送時には指向性ビームを変更せずに、変調方式、符号化方式をよりロバストな方式（たとえば、多値数を減らす、誤り訂正を強化する等）に変更することが望ましい。しかしながら、誤りの原因が特定できないため、従来の再送方式は非効率になりがちであった。また、Ｄａｔａフレーム長が長い場合は、特に効率が低下していた。図２４Ｂのように、端末局ＳＴＡが、基地局ＡＰ宛てに送信したＤａｔａが誤った場合も同様である。 Third Embodiment
FIGS. 24A and 24B show examples of cases where the beam directivity at the time of Data transmission is not appropriate in frame exchange using the directional repetitive transmission shown in FIGS. 9A and 9B. As shown in FIG. 24A, the base station AP transmits Data using a directional beam suitable for transmission to the terminal station STA, but when there is a change in the wireless communication environment, the directional beam is not appropriate, and as a result In some cases, Data can not be correctly transmitted to the destination terminal station STA. In such a case, the base station AP retransmits the Data using the directional repetitive transmission method or the like, but if this method does not actually transmit Data, the directional beam is correct or not. I can not judge. In addition, when Data transmission is transmitted by a highly efficient multi-level modulation method, it is judged whether SINR is insufficient due to inadequate directional beam or SINR is insufficient although directional beam is appropriate. Is difficult. In the former case, it is preferable to change the directional beam at the time of retransmission, and in the latter case, the modulation scheme and the coding method can be made more robust without changing the directional beam at the time of retransmission (e.g. It is desirable to change it to reduce However, conventional retransmission methods tend to be inefficient because the cause of the error can not be identified. In addition, when the Data frame length is long, the efficiency is particularly reduced. The same applies to the case where the data sent by the terminal station STA to the base station AP is incorrect as shown in FIG. 24B.
　そこで、第３の実施形態は、この問題を解決するための手法を提案する。図２５Ａ、２５Ｂは、第３の実施形態に係る無線通信装置の構成例を示すブロック図である。図２５Ａは、上記図１の構成にチャネル推定信号生成部１５を設けたものである。図２５Ｂは、上記図１の構成にビーム選択信号生成部１６を設けたものである。なお、図１の構成に、チャネル推定信号生成部１５とビーム選択信号生成部１６との両方を設けても良い。図２５Ａにおいて、チャネル推定信号生成部１５は、送信元が適切なチャネルを推定するために用いるサウンディング信号（チャネル推定信号）を生成する。図２５Ｂにおいて、ビーム選択信号生成部１６は、送信元が最適な指向性ビームを選択できるようにするための情報（ビーム選択信号）を生成する。 Thus, the third embodiment proposes a method for solving this problem. 25A and 25B are block diagrams showing an example of the configuration of a wireless communication apparatus according to the third embodiment. FIG. 25A shows the configuration of FIG. 1 provided with a channel estimation signal generation unit 15. FIG. 25B is obtained by providing the beam selection signal generation unit 16 in the configuration of FIG. Note that both the channel estimation signal generation unit 15 and the beam selection signal generation unit 16 may be provided in the configuration of FIG. 1. In FIG. 25A, the channel estimation signal generation unit 15 generates a sounding signal (channel estimation signal) that the transmission source uses to estimate an appropriate channel. In FIG. 25B, the beam selection signal generation unit 16 generates information (a beam selection signal) for enabling the transmission source to select an optimal directional beam.
　図２６に、第３の実施形態における物理ヘッダの構成例を示す。図２６は、上記図６Ａの物理ヘッダに、宛先アドレス情報を付加したものである。この宛先アドレスは、通常ＭＡＣヘッダに付加されるべき情報であるが、ここでは、物理ヘッダにも付加することとする。ＭＡＣヘッダには、宛先アドレスを付加しても良いし、付加しなくても良い。 FIG. 26 shows a configuration example of the physical header in the third embodiment. In FIG. 26, destination address information is added to the physical header of FIG. 6A. This destination address is usually information to be added to the MAC header, but here it is also added to the physical header. A destination address may or may not be added to the MAC header.
　図２７は、第３の実施形態に係る無線通信装置の受信動作を示すフローチャートである。　
　受信フレーム解析部１４は、第１のフィールドを受信すると（ステップＳ１ｄ）、物理ヘッダに含まれるチャネル予定期間を取得する（ステップＳ２ｄ）と共に、物理ヘッダに含まれる宛先アドレスを取得する（ステップＳ３ｄ）。受信フレーム解析部１４は、取得された宛先アドレスが自局宛てである場合は（ステップＳ４ｄ）、第２のフィールドの受信を試みる（ステップＳ５ｄ）。ステップＳ５ｄにおいて、第２のフィールドが受信された場合は、送受信部１２はその後の送受信処理を行う（ステップＳ６ｄ）。一方、ステップＳ４ｄにおいて宛先アドレスが自局宛てでない場合は、送受信部１２はチャネル予定期間の送信を停止する（ステップＳ７ｄ）。また、図２７のステップＳ５ｄにおいて第２のフィールドが受信できなかった場合は、チャネル推定信号生成部１５ではチャネル推定信号の生成処理、または、ビーム選択信号生成部１６ではビーム選択信号の生成処理を行う（ステップＳ８ｄ）。 FIG. 27 is a flowchart showing the reception operation of the wireless communication apparatus according to the third embodiment.
When receiving the first field (step S1d), the reception frame analysis unit 14 acquires a channel scheduled period included in the physical header (step S2d) and acquires a destination address included in the physical header (step S3d). . If the acquired destination address is addressed to the own station (step S4d), the reception frame analysis unit 14 attempts to receive the second field (step S5d). If the second field is received in step S5d, the transmission / reception unit 12 performs the subsequent transmission / reception process (step S6d). On the other hand, when the destination address is not addressed to the own station in step S4d, the transmission / reception unit 12 stops transmission of the channel scheduled period (step S7d). If the second field can not be received in step S5d of FIG. 27, the channel estimation signal generation unit 15 generates a channel estimation signal, or the beam selection signal generation unit 16 generates a beam selection signal. Perform (step S8d).
　さらに、ステップＳ４ｄにおいて宛先アドレスが自局宛てでない場合には、受信処理を停止するようにしても良い。図２８に示すように、端末局ＳＴＡ２が、端末局ＳＴＡ１宛ての無線フレームを受信した場合は、物理ヘッダに含まれるチャネル予定期間の間は、基地局ＡＰと端末局ＳＴＡ１間の通信が行われていると判断して、その間の受信処理を停止（電源供給をとめたり、クロック供給を止めたり）する。なお、基地局ＡＰや端末局ＳＴＡ１が送信する第２のフィールドは、宛先方向に向けた指向性ビームを用いて送信されるため、端末局ＳＴＡ２は電力検出をできないこともあるが、物理ヘッダに含まれるチャネル予定期間の間は、基地局ＡＰと端末局ＳＴＡ１間の通信が行われていると判断する。これにより、無駄な電力を浪費することを削減できるため、低消費電力化につながる。 Furthermore, when the destination address is not addressed to the own station in step S4d, the reception process may be stopped. As shown in FIG. 28, when the terminal station STA2 receives a radio frame addressed to the terminal station STA1, communication between the base station AP and the terminal station STA1 is performed during a channel scheduled period included in the physical header. And stop the reception processing (stop the power supply or stop the clock supply). Since the second field transmitted by the base station AP or the terminal station STA1 is transmitted using a directional beam directed to the destination direction, the terminal station STA2 may not be able to detect the power, but It is determined that communication between the base station AP and the terminal station STA1 is being performed during the included channel scheduled period. As a result, wasteful power consumption can be reduced, leading to lower power consumption.
　ステップＳ８ｄにおいて、ビームの指向性が適切でないために第２のフィールドが受信できなかった場合に、チャネル推定信号を送信する場合の動作について説明する。　
　図２９Ａ，２９Ｂでは、自局宛の宛先アドレスが付加された物理ヘッダを含む第１のフィールドを受信した場合を示す。図２９Ａでは、指向性反復伝送で送信された第１のフィールドを受信できるものの、それ以降に続く、第２のフィールド以降の情報を正しく受信できなかった場合（フレームチェックシーケンスでエラ－）に、端末局ＳＴＡの受信フレーム解析部１４は、基地局ＡＰが自局宛てに形成したビームが適切でないと判断することができる。特に、第１のフィールド伝送に用いた変調方式、誤り訂正方式と、第２のフィールド伝送に用いた変調方式、誤り訂正方式が同じである場合や、第２のフィールド伝送に用いた変調方式、誤り訂正方式の方がよりロバストな方式の場合に、その判断はより適切となる。また、図２９Ｂのように、第２フィールド以降の受信レベルが急激に劣化し、ほとんど受信できない場合も、端末局ＳＴＡは、基地局ＡＰが自局宛てに形成したビームが適切でないと判断することができる。また、第１のフィールドの受信電力と第２のフィールドの受信電力を比較し、その差が予め定めたスレッショルド以上になった場合には、ビームが適切でないと判断することもできる。 The operation in the case of transmitting a channel estimation signal when the second field can not be received because the directivity of the beam is not appropriate in step S8d will be described.
29A and 29B show the case where the first field including the physical header to which the destination address addressed to the own station is added is received. In FIG. 29A, although the first field transmitted in the directional repetitive transmission can be received, the subsequent information after the second field can not be received correctly (error in frame check sequence), The reception frame analysis unit 14 of the terminal station STA can determine that the beam formed by the base station AP for itself is not appropriate. In particular, the modulation scheme used for the first field transmission, the error correction scheme, the modulation scheme used for the second field transmission, the case where the error correction scheme is the same, or the modulation scheme used for the second field transmission, The decision is more appropriate if the error correction scheme is more robust. Further, as shown in FIG. 29B, even if the reception level in the second field and onwards is rapidly deteriorated and reception is hardly possible, the terminal station STA determines that the beam formed by the base station AP to the own station is not appropriate. Can. It is also possible to compare the received power of the first field and the received power of the second field, and determine that the beam is not appropriate if the difference is greater than or equal to a predetermined threshold.
　このような場合、端末局ＳＴＡのチャネル推定信号生成部１５は、ＲＴＳの受信が完了して所定の時間が経過した後に、基地局ＡＰに対して、基地局ＡＰがチャネル推定するために必要なチャネル推定信号を送信する。また、図２９Ｂのように、ＲＴＳの第２のフィールド以降が全く受信できなかった場合であっても、ＲＴＳの物理ヘッダには、ＲＴＳフレーム長に関する情報が付加されているため、端末局ＳＴＡは、ＲＴＳフレームの終了時刻を把握することができるため、チャネル推定信号を送信すべきタイミングを認識することができる。 In such a case, the channel estimation signal generation unit 15 of the terminal station STA requires the base station AP to perform channel estimation for the base station AP after the reception of RTS is completed and a predetermined time has elapsed. Transmit channel estimation signal. Further, even if the second and subsequent fields of the RTS can not be received at all as shown in FIG. 29B, since the information on the RTS frame length is added to the physical header of the RTS, the terminal station STA Since the end time of the RTS frame can be grasped, the timing to transmit the channel estimation signal can be recognized.
　また、ステップＳ８ｄにおいて、ビームの指向性が適切でないために第２のフィールドが受信できなかった場合に、ビーム制御信号を送信する場合の動作について説明する。　
　図３０Ａ，３０Ｂでは、自局宛の宛先アドレスが付加された物理ヘッダを含む第１のフィールドを受信した場合を示す。図３０Ａ，３０Ｂにおいて、指向性反復伝送される第１のフィールドの信号から、使用されているビームの識別子を認識できる場合には、端末局ＳＴＡは、基地局ＡＰが使用するビームの中で最適なビームを選択することができる。このような場合に、端末局ＳＴＡのビーム選択信号生成部１６は、ＲＴＳフレームを正しく受信しなかった場合や、ＲＴＳの第２フィールドを受信できなかった場合には、ＲＴＳの受信が完了して所定の時間が経過した後に、基地局ＡＰに対して、最適なビームを通知するためのビーム選択信号を送信する。 In addition, an operation in the case of transmitting a beam control signal when the second field can not be received because the directivity of the beam is not appropriate in step S8 d will be described.
30A and 30B show the case where the first field including the physical header to which the destination address addressed to the own station is added is received. In FIGS. 30A and 30B, when the identifier of the beam being used can be recognized from the signal of the first field transmitted by directional repetition, the terminal station STA is the best of the beams used by the base station AP. Can be selected. In such a case, the beam selection signal generation unit 16 of the terminal station STA completes the reception of RTS when the RTS frame is not correctly received or when the second field of RTS is not received. After a predetermined time has elapsed, the base station AP transmits a beam selection signal for notifying an optimum beam.
　このようにすることで、基地局ＡＰは、図２４Ａ，２４Ｂのような方法に比べ、速やかに最適なビームを決定できて、効率良く再送処理を実行することができる。また、ＲＴＳフレームを正しく受信したにも関わらず、Ｄａｔａフレームを正しく受信できなかった場合には、ビーム指向性は正しいものの、選択している変調方式が不適切であると判断し、ビーム指向性は維持したまま、よりロバストな変調方式、符号化方式に変更することが可能となる。 By doing this, the base station AP can determine the optimum beam more quickly than in the method shown in FIGS. 24A and 24B, and can perform retransmission processing efficiently. In addition, even though the RTS frame is correctly received, if the Data frame can not be received correctly, although the beam directivity is correct, it is determined that the selected modulation scheme is inappropriate, and the beam directivity is determined. It is possible to change to a more robust modulation scheme and coding scheme while maintaining.
　また、図２６に示した物理ヘッダを付加した無線信号を送信することで、広範囲の無線局に対して、チャネル予定期間を通知し、かつ、その無線フレームが、どの無線局宛てであるかを通知することができる。したがって、宛先に指定されていない無線局は、物理ヘッダを解析した後は、そのフレームの第２フィールド以降のデータを受信する必要がないため、受信処理を停止し、省電力化を図ることができる。また、チャネル予定期間は、受信処理を停止して良いことも把握することができる。 Further, by transmitting a radio signal to which the physical header shown in FIG. 26 is added, a channel scheduled period is notified to a wide range of radio stations, and which radio station the radio frame is addressed to It can be notified. Therefore, after analyzing the physical header, the wireless station not designated as the destination does not need to receive data after the second field of the frame, so the reception process may be stopped to save power. it can. Also, it is possible to know that the channel scheduled period may stop the reception process.
　なお、物理ヘッダに付加する宛先アドレスは、オ－バヘッドを削減するためにハッシュ関数等の可逆な圧縮方法で、情報量を圧縮してもよい。もしくは、非可逆な圧縮方法で圧縮しても良い。非可逆な圧縮方法としては、単純に、ＭＡＣアドレスの下位数ビットを物理ヘッダに付加する宛先アドレスとして用いることもできる。非可逆な圧縮方法で圧縮した場合は、ＭＡＣヘッダにも宛先アドレス情報を付加しておき、物理ヘッダに含まれる宛先アドレスに係わる情報を解析することにより、その無線パケットが自局宛てである可能性があるか、ないかの判断をする。自局宛てである可能性がある場合は引き続き受信処理を行い、ＭＡＣヘッダに付加された宛先アドレスを見て、最終的に、自局宛てであるか否かの判断をしても良い。 The amount of information of the destination address added to the physical header may be compressed by a reversible compression method such as a hash function in order to reduce the overhead. Alternatively, it may be compressed by an irreversible compression method. As a lossy compression method, it is also possible to simply use the lower few bits of the MAC address as the destination address to be added to the physical header. When compression is performed using a lossy compression method, the wireless packet can be addressed to the local station by adding destination address information to the MAC header and analyzing information related to the destination address included in the physical header. Determine if there is sex or not. If there is a possibility of being addressed to the own station, reception processing may be continued, and the destination address added to the MAC header may be checked to finally determine whether the address is addressed to the own station.
　（第４の実施形態）　
　図３１に、第４の実施形態に係る無線通信装置が構成するネットワーク構成例を示す。図３１において、端末局ＳＴＡ１－１～１－２は、基地局ＡＰ１に接続しており、端末局ＳＴＡ２－１～２－２は、基地局２に接続しているものとする。また、端末局ＳＴＡ２－２は、基地局ＡＰ１と基地局ＡＰ２の双方の通信エリアに位置している。したがって、端末局ＳＴＡ２－２は、基地局ＡＰ２が送信した無線信号だけでなく、基地局ＡＰ１が送信した無線信号も受信することができる。そうすると、基地局ＡＰ１は、基地局２に接続する端末局ＳＴＡ２－２に対してもチャネル予約をしてしまい、空間多重によるチャネル効率改善効果が低下してしまう恐れがある。 Fourth Embodiment
FIG. 31 shows an example of the network configuration of the wireless communication apparatus according to the fourth embodiment. In FIG. 31, the terminal stations STA1-1 to 1-2 are connected to the base station AP1, and the terminal stations STA2-1 to 2-2 are connected to the base station 2. The terminal station STA2-2 is located in the communication area of both the base station AP1 and the base station AP2. Therefore, the terminal station STA2-2 can receive not only the radio signal transmitted by the base station AP2, but also the radio signal transmitted by the base station AP1. Then, the base station AP1 also reserves a channel for the terminal station STA2-2 connected to the base station 2, and there is a risk that the channel efficiency improvement effect by spatial multiplexing may be reduced.
　そこで、第４の実施形態では、このような問題を解決するための手法を提案する。　
　第４の実施形態の構成は、上記図１の構成と同様のため、図１を用いて説明を行う。なお、第４の実施形態は、物理ヘッダの構成と、制御部１２３の動作が異なるものである。図３２に、第４の実施形態における物理ヘッダの構成例を示す。図３２は、上記図６Ａの物理ヘッダに、無線チャネルを識別するネットワーク識別子（無線回線を識別する情報）を付加したものである。 Therefore, in the fourth embodiment, a method for solving such a problem is proposed.
The configuration of the fourth embodiment is the same as the configuration of FIG. 1 described above, and therefore will be described using FIG. In the fourth embodiment, the configuration of the physical header and the operation of the control unit 123 are different. FIG. 32 shows a configuration example of the physical header in the fourth embodiment. FIG. 32 shows the physical header of FIG. 6A added with a network identifier (information for identifying a wireless channel) for identifying a wireless channel.
　図３３は、第４の実施形態に係る無線通信装置の受信動作を示すフローチャートである。　
　受信フレーム解析部１４は、第１のフィールドを受信すると（ステップＳ１ｅ）、物理ヘッダに含まれるチャネル予定期間を取得する（ステップＳ２ｅ）と共に、物理ヘッダに含まれるネットワーク識別子を取得する（ステップＳ３ｅ）。受信フレーム解析部１４は、自局が所属しているネットワークのネットワーク識別子と取得したネットワーク識別子と同一であるか否かを判定し（ステップＳ４ｅ）、自局が所属しているネットワーク識別子と異なる場合は、物理ヘッダに含まれるチャネル予約情報を無視する。つまり、チャネルが予約されていると判断しないことにする。 FIG. 33 is a flowchart showing the reception operation of the wireless communication apparatus according to the fourth embodiment.
When receiving the first field (step S1e), the reception frame analysis unit 14 acquires a channel scheduled period included in the physical header (step S2e) and acquires a network identifier included in the physical header (step S3e). . The reception frame analysis unit 14 determines whether or not the network identifier of the network to which the own station belongs is identical to the acquired network identifier (step S4e), and is different from the network identifier to which the own station belongs Ignores the channel reservation information contained in the physical header. That is, it is not determined that the channel is reserved.
　一方、ステップＳ４ｅの判定において、自局が所属しているネットワークのネットワーク識別子と取得したネットワーク識別子と同一である場合に、さらに第２のフィールドを受信した場合は（ステップＳ５ｅ）、受信した第２のフィールドからＭＡＣヘッダを取得する（ステップＳ６ｅ）。取得したＭＡＣヘッダに含まれる宛先アドレスが自局宛てである場合は（ステップＳ７ｅ）、送受信部１２はその後の送受信処理を行う（ステップＳ８ｅ）。一方、ステップＳ５ｅにおいて第２のフィールドが受信できなかった場合は、チャネル予定期間の送信を停止する（ステップＳ９ｅ）。また、ステップＳ７ｅにおいて宛先アドレスが自局宛てでない場合は、送受信部１２はチャネル予定期間の送受信を停止する（ステップＳ１０ｅ）。 On the other hand, if it is determined in step S4e that the network identifier of the network to which the own station belongs is identical to the acquired network identifier, and if the second field is further received (step S5e), the received second The MAC header is acquired from the field of (step S6e). If the destination address included in the acquired MAC header is addressed to the local station (step S7e), the transmission / reception unit 12 performs the subsequent transmission / reception process (step S8e). On the other hand, when the second field can not be received in step S5e, transmission of the channel scheduled period is stopped (step S9e). If the destination address is not addressed to the local station in step S7e, the transmission / reception unit 12 stops transmission / reception of the channel scheduled period (step S10e).
　例えば、図３４Ａに示すように、基地局ＡＰ１が端末局ＳＴＡ１－１宛てに送信した無線信号を端末局ＳＴＡ１－１、ＳＴＡ１－２、及びＳＴＡ２－２が受信したとする。端末局ＳＴＡ１－１は、自局宛ての無線信号であるため、その後も基地局ＡＰ１との通信を行う。 For example, as shown in FIG. 34A, it is assumed that the terminal stations STA1-1, STA1-2, and STA2-2 receive the radio signal transmitted to the terminal station STA1-1 by the base station AP1. Since the terminal station STA1-1 is a radio signal directed to itself, it continues to communicate with the base station AP1 thereafter.
　端末局ＳＴＡ１－２は、ＲＴＳフレームの第１のフィールドを受信し、物理ヘッダに付加されたネットワーク識別子により、自局が所属するネットワークの信号であると判断すると、その後も受信を続けるが、ＲＴＳの第２のフィールドを受信した際に、そのフレームが自局宛てでないと判断する。そこで、基地局ＡＰ１と端末局ＳＴＡ１－１との通信が行われている期間、すなわち、チャネル予定期間の間、送受信処理を停止する。 If the terminal station STA1-2 receives the first field of the RTS frame and determines that it is a signal of the network to which the own station belongs by the network identifier added to the physical header, it continues reception thereafter, but When the second field of is received, it is determined that the frame is not addressed to its own station. Therefore, transmission and reception processing is stopped during a period in which communication between the base station AP1 and the terminal station STA1-1 is being performed, that is, a channel scheduled period.
　一方、端末局ＳＴＡ２－２は、ＲＴＳフレームの第１のフィールドを受信したところ、物理ヘッダに付加されたネットワーク識別子により、自局が所属するネットワークとは異なるネットワークの信号であることを検出する。そして、端末局ＳＴＡ２－２は、物理ヘッダに含まれるチャネル予定期間をキャンセルし、それ以降も受信処理を継続する。必要に応じて送信処理も行うことができる。これは、図３１で示したように、ネットワークが異なる場合は、一般的に端末局ＳＴＡ２－２が基地局ＡＰ２宛てに送信する信号が、基地局ＡＰ１に所属する端末局ＳＴＡ１－１の通信に及ぼす影響が小さいと考えられるため、送信を抑止するよりは、通常の送受信を継続した方が、空間的な通信効率が向上すると考えられるためである。 On the other hand, when the terminal station STA2-2 receives the first field of the RTS frame, it detects from the network identifier added to the physical header that it is a signal of a network different from the network to which the own station belongs. Then, the terminal station STA2-2 cancels the channel scheduled period included in the physical header, and continues the reception process thereafter. Transmission processing can also be performed as needed. This is because, as shown in FIG. 31, when the network is different, in general, the signal transmitted from the terminal station STA2-2 to the base station AP2 is for the communication of the terminal station STA1-1 belonging to the base station AP1. Since the influence exerted is considered to be small, it is considered that spatial communication efficiency is improved if normal transmission and reception are continued rather than transmission suppression.
　但し、図３４Ａの方式は、端末局ＳＴＡ１－２が、ＲＴＳフレームの第１のフィールドを受信するものの、その後の第２のフィールドの受信に誤った場合に、それが自局宛てであるか否か判断できないため、その時点で送受信処理を停止することができないという課題が残る。 However, in the scheme of FIG. 34A, although the terminal station STA1-2 receives the first field of the RTS frame, if the terminal station STA1-2 erroneously receives the second field thereafter, whether or not it is addressed to itself. There is still a problem that transmission and reception processing can not be stopped at that time because it can not be determined.
　そこで、図３５に示すように、図９に示す物理ヘッダに、宛先アドレスとネットワーク識別子の双方を付加するようにする。このようにすると、図３４Ｂに示すように、端末局ＳＴＡ１－２は、ＲＴＳフレームの第１のフィールドを受信した時点で、物理ヘッダに含まれる宛先アドレスから、そのフレームが自局宛てでないことを判断できるため、図３４Ａの方式に比べて、送受信処理の停止を早くすることができ、より一層の低消費電力化に効果がある。 Therefore, as shown in FIG. 35, both the destination address and the network identifier are added to the physical header shown in FIG. In this way, as shown in FIG. 34B, when the terminal station STA1-2 receives the first field of the RTS frame, it is determined from the destination address contained in the physical header that the frame is not addressed to itself. Since the determination can be made, the transmission / reception process can be stopped earlier compared to the method of FIG. 34A, which is effective in further reducing power consumption.
　上記第４の実施形態によれば、ネットワーク識別子を付加した物理ヘッダを用いることで、端末局は、チャネル予定期間の情報だけでなく、ネットワーク識別子情報を把握できるため、他の基地局に所属する端末局まで必要以上に送信抑制をしてしまうことがなくなる。つまり、異なるネットワーク機器同士での同時送信が可能となり、空間利用効率を向上させることができる。なお、ネットワーク識別子は、宛先アドレスと同様に、可逆圧縮や非可逆圧縮をして情報量削減をしても良い。 According to the fourth embodiment, by using the physical header to which the network identifier is added, the terminal station can grasp not only the information of the channel scheduled period but also the network identifier information, and thus belongs to another base station. It is no longer necessary to suppress transmission to the terminal station more than necessary. That is, simultaneous transmission between different network devices becomes possible, and space utilization efficiency can be improved. The network identifier may be losslessly compressed or losslessly compressed to reduce the amount of information, similarly to the destination address.
　また、上記実施形態では、図１の無線通信装置の構成例に基づいて説明したが、セクタアンテナを用いた図３６の無線通信装置の構成例にも適用することができる。すなわち、複数の指向性を有するセクタアンテナを順次切り替えながらＲＦ信号を送信することにより、指向性反復伝送を実現してもよい。そして、この構成をベースに図２５Ａで示したようなチャネル推定信号生成部１５、または、図２５Ｂでビーム選択信号生成部１６を設けても良い。 Further, although the above embodiment has been described based on the configuration example of the wireless communication apparatus of FIG. 1, the embodiment can be applied to the configuration example of the wireless communication apparatus of FIG. 36 using a sector antenna. That is, directional repeat transmission may be realized by transmitting an RF signal while sequentially switching a plurality of sector antennas having directivity. Then, based on this configuration, the channel estimation signal generation unit 15 as shown in FIG. 25A or the beam selection signal generation unit 16 in FIG. 25B may be provided.
　なお、この発明は、上記実施形態そのままに限定されるものではなく、実施段階ではその要旨を逸脱しない範囲で構成要素を変形して具体化できる。また、上記実施形態に開示されている複数の構成要素の適宜な組み合せにより種々の発明を形成できる。例えば、実施形態に示される全構成要素から幾つかの構成要素を削除してもよい。さらに、異なる実施形態に亘る構成要素を適宜組み合せてもよい。 The present invention is not limited directly to the above-described embodiment. In practice, the structural elements can be modified without departing from the spirit of the invention. In addition, various inventions can be formed by appropriate combinations of a plurality of components disclosed in the above embodiments. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, components in different embodiments may be combined as appropriate.
　１…無線通信装置、１１…アンテナ部、１２送受信部、１３送信フレーム生成部、１４…受信フレーム解析部、１２１…ＲＦユニット、１２２…ビーム形成部、１２３…制御部、１Ａ…無線通信装置、１５…チャネル推定信号生成部、１６…ビーム選択信号生成部。 DESCRIPTION OF SYMBOLS 1 ... Radio | wireless communication apparatus, 11 ... Antenna part, 12 transmission / reception part, 13 Transmission frame production | generation part, 14 ... Reception frame analysis part, 121 ... RF unit, 122 ... Beam formation part, 123 ... Control part, 1A ... Wireless communication apparatus, 15 Channel estimation signal generation unit 16 Beam selection signal generation unit

Claims (8)

  1. 　無線回線を宛先との間の通信に使用する予定期間を示す情報を付加した物理ヘッダを含む第１のフィールドと、前記第１のフィールドに後続する、ペイロードを含む第２のフィールドとを含む送信フレームを生成する送信フレーム生成部と、
    　前記第１のフィールド及び第２のフィールドのそれぞれに対して、方向の異なる複数の指向性ビームを切り替えて形成する第１のモードと前記宛先の方向に指向性ビームを形成する第２のモードとを選択的に用いて前記送信フレームを送信する送信部と
    を具備することを特徴とする無線通信装置。     Transmission including a first field including a physical header added with information indicating a scheduled period for using a wireless circuit for communication with a destination, and a second field including a payload following the first field A transmission frame generation unit that generates a frame;
    A first mode in which a plurality of directional beams different in direction are switched and formed for each of the first field and the second field, and a second mode in which directional beams are formed in the direction of the destination And a transmitter configured to transmit the transmission frame by selectively using.
  2. 　前記送信部は、前記第１のフィールドを送信するために、前記送信フレームのタイプに応じて、前記第１のモード及び第２のモードのいずれかを選択することをさらに特徴とする請求項１記載の無線通信装置。 The transmission unit may further select any one of the first mode and the second mode according to a type of the transmission frame to transmit the first field. A wireless communication device as described.
  3. 　前記送信部は、前記第２のフィールドを送信するために、前記宛先に応じて、前記第１のモード及び第２のモードのいずれかを選択することをさらに特徴とする請求項１記載の無線通信装置。 The wireless transmission system according to claim 1, wherein the transmitter selects one of the first mode and the second mode in accordance with the destination to transmit the second field. Communication device.
  4. 　前記送信部は、前記宛先がブロードキャストの場合に、前記第２のフィールドを前記第１のモードで送信することをさらに特徴とする請求項３記載の無線通信装置。 4. The wireless communication apparatus according to claim 3, wherein the transmitting unit transmits the second field in the first mode when the destination is a broadcast.
  5. 　前記送信フレーム生成部は、前記物理ヘッダに前記第２のフィールドを前記第１のモード及び第２のモードのうちいずれで送信するかを表すビーム制御情報を付加することをさらに特徴とする請求項１記載の無線通信装置。 The transmission frame generation unit is further characterized in that beam control information indicating whether the second field is to be transmitted in the first mode or the second mode is added to the physical header. The wireless communication device according to 1.
  6. 　前記送信フレーム生成部は、前記物理ヘッダに前記宛先を識別する情報を付加することをさらに特徴とする請求項１記載の無線通信装置。 The wireless communication apparatus according to claim 1, wherein the transmission frame generation unit adds information identifying the destination to the physical header.
  7. 　前記送信フレーム生成部は、前記物理ヘッダに前記無線回線を識別する情報を付加することをさらに特徴とする請求項１記載の無線通信装置。 The wireless communication apparatus according to claim 1, wherein the transmission frame generation unit adds information identifying the wireless channel to the physical header.
  8. 　前記予定期間の開始時刻は、前記第２のフィールドの送信が開始される予定時刻となるように算出されることを特徴とする請求項１記載の無線通信装置。 The wireless communication apparatus according to claim 1, wherein the start time of the scheduled period is calculated to be a scheduled time at which the transmission of the second field is started.
PCT/JP2009/068723 2008-10-31 2009-10-30 Radio communication device WO2010050599A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2008282409A JP2010109939A (en) 2008-10-31 2008-10-31 Radio communication device
JP2008-282409 2008-10-31

Publications (1)

Publication Number Publication Date
WO2010050599A1 true WO2010050599A1 (en) 2010-05-06

Family

ID=42128958

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2009/068723 WO2010050599A1 (en) 2008-10-31 2009-10-30 Radio communication device

Country Status (2)

Country Link
JP (1) JP2010109939A (en)
WO (1) WO2010050599A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013190904A1 (en) * 2012-06-21 2013-12-27 オリンパス株式会社 Wireless communication terminal, wireless communication system, wireless communication method, and program

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6256866B2 (en) * 2013-02-14 2018-01-10 国立研究開発法人情報通信研究機構 Wireless communication system and method
JP2015149602A (en) * 2014-02-06 2015-08-20 日本電信電話株式会社 wireless communication system and wireless communication method
BR112017000089B1 (en) 2014-07-11 2023-12-12 Sony Corporation INFORMATION PROCESSING DEVICE, INFORMATION PROCESSING METHOD, AND NON-TRAINER COMPUTER READABLE MEDIUM
WO2016041303A1 (en) 2014-09-19 2016-03-24 华为技术有限公司 Wireless local area network data transmission method and device
JP6578831B2 (en) 2015-09-08 2019-09-25 ソニー株式会社 Wireless communication apparatus and wireless communication method
EP3376798B1 (en) * 2015-11-11 2021-10-20 Sony Group Corporation Communication device and communication method
JP6623135B2 (en) * 2015-12-25 2019-12-18 株式会社東芝 Wireless communication device
US10524289B2 (en) 2015-12-25 2019-12-31 Kabushiki Kaisha Toshiba Wireless communication device
CN109565673B (en) 2016-08-12 2022-02-18 日本电气株式会社 Device, method, system, program and recording medium relating to beam and security enhancement

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH1093564A (en) * 1996-06-17 1998-04-10 Internatl Business Mach Corp <Ibm> Communication medium access control method in radio communication network to support a plurality of transmission rates
JPH11136735A (en) * 1997-10-27 1999-05-21 Toshiba Corp Radio communication system
JP2003163669A (en) * 2001-11-27 2003-06-06 Canon Inc Radio communication equipment
JP2006074820A (en) * 2001-09-28 2006-03-16 Toshiba Corp Wireless communication apparatus and frame transmission method
WO2007142205A1 (en) * 2006-06-09 2007-12-13 Kyocera Corporation Base station, mobile station, and mobile communication method
JP2007537674A (en) * 2004-05-14 2007-12-20 インターデイジタル テクノロジー コーポレーション Method for selectively adjusting the antenna configuration of an access point to enhance mobile station coverage

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH1093564A (en) * 1996-06-17 1998-04-10 Internatl Business Mach Corp <Ibm> Communication medium access control method in radio communication network to support a plurality of transmission rates
JPH11136735A (en) * 1997-10-27 1999-05-21 Toshiba Corp Radio communication system
JP2006074820A (en) * 2001-09-28 2006-03-16 Toshiba Corp Wireless communication apparatus and frame transmission method
JP2003163669A (en) * 2001-11-27 2003-06-06 Canon Inc Radio communication equipment
JP2007537674A (en) * 2004-05-14 2007-12-20 インターデイジタル テクノロジー コーポレーション Method for selectively adjusting the antenna configuration of an access point to enhance mobile station coverage
WO2007142205A1 (en) * 2006-06-09 2007-12-13 Kyocera Corporation Base station, mobile station, and mobile communication method

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013190904A1 (en) * 2012-06-21 2013-12-27 オリンパス株式会社 Wireless communication terminal, wireless communication system, wireless communication method, and program
JP2014007440A (en) * 2012-06-21 2014-01-16 Olympus Corp Radio communication terminal, radio communication system, and radio communication method and program
US9769727B2 (en) 2012-06-21 2017-09-19 Olympus Corporation Wireless communication terminal, wireless communication system, wireless communication method, and program

Also Published As

Publication number Publication date
JP2010109939A (en) 2010-05-13

Similar Documents

Publication Publication Date Title
WO2010050599A1 (en) Radio communication device
KR101500973B1 (en) Enhanced multi-user transmission
US6862456B2 (en) Systems and methods for improving range for multicast wireless communication
US8675617B2 (en) Methods for improving wireless communications when interference or signal loss is directional in nature
US8553548B2 (en) Collision mitigation for multicast transmission in wireless local area networks
JP4670934B2 (en) Wireless communication system, wireless communication device, wireless communication method, and computer program
US8792577B2 (en) Method and apparatus for medium access control in a wireless broadband system with multiple-input multiple-output or multiple-input single-output technology with multiuser capabilities
EP1601126A2 (en) Transmission of feedback information in a wireless communications system
US8554148B2 (en) Data transmission/reception apparatus and method for wireless communication system
US7606213B2 (en) Wireless MAC layer throughput improvements
JP4886733B2 (en) Wireless communication system and wireless terminal
JP2010500785A (en) Method and system for antenna selection in a wireless network
EP1578063A2 (en) Radio transmitting apparatus provided with transmitters and transmitting antennas
US10524288B2 (en) Method and apparatus for increasing transmission coverage of STA performing initial access in wireless LAN
US7305237B2 (en) Hole-filling channel access
US9425882B2 (en) Wi-Fi radio distribution network stations and method of operating Wi-Fi RDN stations
Liu et al. Cooperative MAC for rate adaptive randomized distributed space-time coding
EP2844000A1 (en) Cooperative relaying for dynamic networks
US20230403741A1 (en) Transmitting and receiving via remote radio head
WO2022054628A1 (en) Communication device
Kim et al. Reliable wireless multicasting with minimum overheads in OFDM-based WLANs
Argyriou et al. Collision recovery in distributed wireless networks with opportunistic cooperation
Trung et al. PHY-MAC cross-layer cooperative protocol supporting physical-layer network coding
Kartsakli et al. Multiuser MAC schemes for high-throughput IEEE 802.11 n/ac WLANs
Thapa et al. Performance analysis of CSMA/CA adapted MIMO aware MAC for multi-user transmission in WLANs

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 09823709

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 09823709

Country of ref document: EP

Kind code of ref document: A1