JP2007235415A - Radio transmitter, radio station, radio terminal, and radio transmission system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio transmitter, radio station, radio terminal and radio transmission system which achieve the time control of a plurality of terminals while performing the directivity control of an antenna, and allow the position etc. of the radio station to be retrieved for a short time. <P>SOLUTION: The radio transmitter of the radio station has a directional antenna for radio communication with one or plurality of radio terminals. It comprises a time control means for controlling the communication timing of each radio terminal so as to give a control signal to a corresponding radio terminal upon arrival of the communication timing of each radio terminal, thereby achieving the communication with the radio terminal; a means for instructing the directivity of the directional antenna every plurality of division communication areas of the communication area; and a means for controlling the directivity of the antenna according to the directivity instruction from the directivity instructing means. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wireless transmission device, a wireless station, a wireless terminal, and a wireless transmission system. For example, in an ultra-high speed wireless transmission system using millimeter waves as transmission waves, an access point controls the directivity of a directional antenna. The present invention can be applied to a radio transmission apparatus, a radio station, a radio terminal, and a radio transmission system that perform access control with terminals existing in a plurality of sectors (communication areas).

  Patent Document 1 is an example of a technique for controlling the directivity of a millimeter wave beam. An automotive antenna device that scans a radiated millimeter wave beam within a predetermined range in order to detect an obstacle and prevent a collision is disclosed. It is disclosed.

  In Non-Patent Document 1, a millimeter-wave broadband radio access network (BRAIN) that implements two-way ultrahigh-speed radio communication using a millimeter-wave with a wide frequency band as a transmission wave. The indoor system is described. Non-Patent Document 1 discloses an example of the appearance of a system, in which an access point and a terminal are fixedly disposed facing each other.

  Non-Patent Document 2 describes a technology related to a millimeter wave transmission system realized by (1) development of a transceiver that wirelessly transmits high-definition video, and (2) development of a small wireless module.

  In addition, it is necessary to clarify the delay time and angle of arrival of incoming waves in order to take measures against multi-fading to realize high-speed wireless transmission. There are 3 mags.

  Patent Document 2 discloses a technique for estimating an arrival angle, a delay time, and the like of an incoming wave by performing predetermined calculation processing using a MUSIC (Multiple Signal Characterization) method.

  Patent Document 3 discloses a method for estimating an incoming wave using a plurality of array antennas and receivers having the number of array antennas.

  Further, the conventional media access control system includes a BTMA (Busy-Tone Multiple Access) system, which uses a busy tone channel for transmitting the usage status of the transmission channel in addition to the transmission channel. By listening to the busy tone channel, it is possible to confirm the availability of the transmission channel instead of the carrier sense of the transmission channel. Moreover, since the usage status of the transmission channel can be transmitted by the busy tone channel, it is possible to suppress the performance degradation due to the presence of the hidden terminal (see Non-Patent Document 3).

JP 2002-189076 A Japanese Patent Laid-Open No. 11-233103 JP 2002-243826 A Incorporated Administrative Agency, Communications Research Laboratory, “BRAIN system adopted by private standard (ARIB STD-T74)”, [On Line], Incorporated Administrative Agency, Communications Research Laboratory website, June 13, 2001, [2005 December 2 search], <http: // www2. nict. go. jp / pub / whatsnew / press / 010613/010613. html> NEC Corporation, "Development of a small millimeter-wave transceiver that realizes cable-less high-definition TV on the wall-Realization of 1Gbps high-speed wireless transmission with palm-sized devices-", [On Line], NEC Corporation website, press Release, April 1, 2005, [Search December 2, 2005], <http: // www. nec. co. jp / press / ja / 0504/013. html> Matsushita Atsushi, Nakagawa Masao, "Wireless LAN Architecture", Kyoritsu Shuppan, 1996, P60

  By the way, in order to realize high-speed wireless communication using millimeter waves, it is necessary to obtain a sufficient gain (gain), and thus it is necessary to use a directional antenna. Therefore, it is assumed that the access point side performs communication by a centralized control protocol that manages each terminal side collectively.

  In this centralized control protocol, the access point side manages the timing (time allocation) at which each terminal can communicate, transmits a control signal notifying each terminal of the communication timing, and the terminal that receives the control signal receives the timing. In this case, the terminal side cannot check the mutual communication status.

  However, conventionally, for example, as disclosed in Non-Patent Document 1, etc., millimeter-wave communication is performed with a directional antenna fixed, and a plurality of sectors (communication areas) with different access points are provided. A centralized control protocol for performing wireless communication with a plurality of terminals while controlling the directivity of the network has not been developed.

  Patent Document 1 discloses a technique for controlling the directivity of a millimeter wave beam. However, the technique of Patent Document 1 does not perform bidirectional communication, but does perform millimeter wave wireless communication. It cannot be applied as it is.

  In addition, the arrival wave estimation method described in Patent Document 2 described above requires complicated arrival wave calculation processing and is complicated, and the technique described in Patent Document 3 is equivalent to the number of array antennas. There is a problem that it is necessary to prepare a receiver.

  Furthermore, the above-described conventional BTMA method is a media access control method for omnidirectional antennas, but a plurality of different communication areas while controlling the directivity of directional antennas for sectors with different access points. There is a need for a transmission control method that is not applicable to a system that communicates with a plurality of terminals existing in the network, and that can be applied to a wireless system having such a directional antenna control function.

  In this case, since the access point is not aware of the presence or direction of the terminal that newly enters the network, there are problems such as a method of searching for such a new terminal and shortening the search time. Become.

  Therefore, in a radio transmission apparatus having a directional antenna and / or a radio transmission apparatus of a radio terminal, centralized control can be realized while controlling the directivity of the directional antenna on the radio station side, and the radio station side There is a need for a wireless transmission device, a wireless station, a wireless terminal, and a wireless transmission system that can search for the position and orientation of the mobile phone in a short time.

  In order to solve such a problem, a wireless transmission device according to a first aspect of the present invention is a wireless transmission device of a wireless station that has a directional antenna and wirelessly communicates with one or a plurality of wireless terminals. It manages the communication timing of the terminal. When the communication timing of each wireless terminal comes, a time management means for giving a control signal to each corresponding wireless terminal and executing communication with the wireless terminal, and (2) a communication area Directionality instruction means for instructing the directivity of the directional antenna for each of the plurality of divided communication areas, and (3) controlling the directivity of the directional antenna according to the directionality instruction from the directivity instruction means. And directional antenna control means.

  A radio transmission apparatus according to a second aspect of the present invention includes an intermittent signal receiving directional antenna for receiving a signal transmitted by a radio station that transmits an intermittent signal, and a communication directional antenna for radio communication. (1) a communication antenna directivity indicating means for instructing the directivity of a data communication directivity antenna based on the received power of a signal received by the intermittent signal reception directivity antenna; ) A communication directivity antenna directivity control means for controlling the directivity of the communication directivity antenna in accordance with an instruction from the communication antenna directivity instruction means.

  According to a third aspect of the present invention, there is provided a wireless station having a directional antenna and wirelessly communicating with one or a plurality of wireless terminals, (1) wireless communication means for wirelessly communicating with each wireless terminal; (2) The wireless transmission apparatus according to the first aspect of the present invention is provided.

  A radio terminal according to a fourth aspect of the present invention performs radio communication by including an intermittent signal receiving directional antenna for receiving a signal transmitted by a radio station that transmits an intermittent signal and a communication directional antenna. The wireless terminal includes (1) wireless communication means for wireless communication with a wireless station, and (2) a wireless transmission device according to the second aspect of the present invention.

  A wireless transmission system according to a fifth aspect of the present invention comprises one or more wireless stations according to the third aspect of the present invention and one or more wireless terminals according to the fourth aspect of the present invention. is there.

  According to the present invention, in the radio transmission apparatus of a radio station and / or radio terminal having a directional antenna, centralized control can be realized while controlling the directivity of the directional antenna on the radio station side. In, the position and direction of a radio station can be searched in a short time.

(A) First Embodiment Hereinafter, a first embodiment of a wireless transmission device, a wireless station, a wireless terminal, and a wireless transmission system of the present invention will be described with reference to the drawings.

  This embodiment is a case where a millimeter-wave ultrahigh-speed wireless system adopting a centralized control protocol is applied to an indoor system, and the wireless transmission apparatus and method of the present invention are applied to an access point having a directivity control function of a directional antenna. The case where is applied will be described.

(A-1) Configuration of the First Embodiment FIG. 2 is a diagram illustrating an example of a configuration for using the wireless communication system of the present embodiment. In FIG. 2, the radio communication system NT of the present embodiment is configured to include an access point AP and a plurality of terminals ST1 to ST5.

  The access point AP is fixedly installed in the upper part (for example, ceiling) of a certain room (section), and has a transmission / reception antenna ANT that is a directional antenna.

  In addition, the access point AP has a plurality of sectors formed by dividing the communication point in a radial pattern with a predetermined angular interval centered on the position of the own access point AP, and exists in each sector. Wireless communication with one or a plurality of terminals ST in accordance with a predetermined wireless communication system. In order to identify a plurality of sectors of the access point AP, numbers such as sector 1, sector 2,..., Sector 5,.

  In this embodiment, since the centralized control protocol is adopted, the access point AP manages (timing allocation management) the timing of wireless communication with all the accommodated terminals ST. A detailed description of the time allocation management method by the access point AP will be given later.

  Further, the access point AP controls the directivity of the transmission / reception antenna ANT for each sector by a predetermined directivity control method.

  Here, although the detailed description of the directivity control method by the access point AP will be described later, the access point AP classifies the sector where the terminal ST performing wireless communication is present and the sector where the terminal is not confirmed, The directivity control of the directional antenna for one or more sectors where the terminal ST performing wireless communication exists is performed in the communication time domain, and the directivity for one or more sectors whose terminal existence has not been confirmed. The directivity control of the antenna is performed within the surrounding terminal confirmation time region.

  Further, although not shown in FIG. 5, the access point AP can be connected to another access point AP by wireless communication and / or wired communication, thereby forming a wide range network by connecting to an external network. You may make it do.

  Terminals ST1 to ST5 are terminals equipped with wireless communication devices that perform wireless communication according to a predetermined wireless communication system via access point AP. Terminals ST1 to ST5 also have directional antennas.

  Here, the wireless communication method between the access point AP and the terminals ST1 to ST5 is, for example, a standard equipment (ultra-high-speed wireless LAN system) for specific low-power wireless station millimeter-wave data transmission of the Japan Radio Industry Association. A millimeter-wave wireless communication system standardized by ARIB STD-T74) can be applied. Of course, the present invention is not limited to this wireless communication system, and any wireless communication system employing a centralized control protocol can be widely applied.

  Next, the internal configuration of the access point AP will be described with reference to FIG. FIG. 3 is a block diagram showing the main internal configuration of the access point AP.

  In FIG. 3, the access point AP of the present embodiment is configured to include at least a MAC (Media Access Control) unit 11, a radio unit 12, and an antenna unit 13.

  The MAC unit 11 performs transmission control in the wireless communication network NT. As shown in FIG. 3, the MAC unit 11 includes at least a media access control unit 111, a time allocation management unit 112, and an antenna directivity instruction unit 113. Have.

  The media access control unit 111 executes transmission control, and executes data frame transmission / reception control, frame formation control, error detection, and the like.

  The time allocation management unit 112 performs time allocation management of the access point AP. The time allocation related to the time allocation management is roughly divided into a peripheral terminal confirmation time region and a communication time region, and these two time regions are managed. Are set alternately and repeatedly. In this case, when the communication is performed with the directional antenna fixed, the surrounding terminal confirmation time area is not required, but the surrounding terminal confirmation time area is provided in order to communicate with a plurality of different sectors.

  Here, the communication time region is a time region for performing wireless communication with the sector where the terminal ST that is performing wireless communication exists, and the access point AP performs wireless communication within this communication time region. Wireless communication with the terminal ST is realized while switching the sector only to the sector having the terminal ST that is performing.

  Further, a down link period, which is a time area in which the access point AP receives data from the terminal ST, and an up link period, which is a time area in which the access point AP transmits data to the terminal ST, are allocated to the communication time area. ing.

  Further, in the present embodiment, a random access area for confirming whether or not there is a terminal ST newly entering the network in the sector within the Up link period is allocated. When the access point AP receives an entry request or a time allocation request from a new entry terminal ST in the sector during the random access area period, the access point AP can confirm the presence of the new entry terminal ST and perform time assignment. .

  Note that the random access area may be provided in each up link period, may be provided in the up link period for each sector, or n (n is a positive integer) times for efficiency of communication. You may make it provide in the up link period once.

  The surrounding terminal confirmation time region is a time region for confirming whether or not the terminal ST has newly entered a sector in which the presence of the terminal ST is unconfirmed, and the access point AP has the surrounding terminal confirmation time. In the area, it is confirmed whether there is a terminal ST that newly enters the network or a terminal ST that is not time-allocated while switching sectors only for the unconfirmed terminal terminal.

  When there is a terminal ST in the surrounding terminal confirmation time area, a Down link period that is a time area in which the access point AP receives an entry request from the terminal ST, and the access point AP exists in the sector. An up link period, which is a time region for transmitting management information on whether or not to perform to the sector, is allocated.

  The area time lengths of the surrounding terminal confirmation time area and the communication time area may be the same, but in order to avoid the wireless communication period from being shortened due to the search period of the unconfirmed presence terminal, the communication time area It is desirable that the area time length of is longer than that of the surrounding terminal confirmation time area. Each time can be determined by setting and can be changed thereafter.

  The antenna directivity instruction unit 113 controls the directivity of the directional antenna ANT with respect to the antenna unit 13 via the radio unit 12, and includes a sector in which a terminal ST performing radio communication exists, and a terminal presence It has information about unidentified sectors.

  The antenna directivity instruction unit 113 controls the directivity of the directional antenna ANT for each sector. As described above, the antenna directivity instruction unit 113 is within the communication time domain for the sector where the terminal ST performing wireless communication exists. To control the directivity of the directional antenna ANT for each sector, and to switch the directivity of the directional antenna ANT for each sector within the surrounding terminal confirmation time region for a sector whose terminal existence has not been confirmed. It is.

  Further, the antenna directivity instruction unit 113 gives an antenna directivity control signal to the antenna unit 13 via the radio unit 12 when directing the directivity of the directional antenna ANT to the sector. When the directivity control of the directivity antenna ANT by the antenna unit 13 is completed, the antenna directivity control unit 13 receives an antenna directivity control completion signal from the antenna unit 13 via the radio unit 12.

  At this time, in the communication time domain, when receiving the antenna directivity control completion signal, the antenna directivity indicating unit 113 recognizes that the directional antenna ANT is directed to the sector and exists in the sector. The management information including the time allocation information of the terminal ST is transmitted.

  And if the antenna directivity instruction | indication part 113 transmits the management information which has the time allocation information of the terminal ST, a Down link period will be allocated, and an Up link period will be allocated after that.

  Also, in the surrounding terminal confirmation time region, when receiving the antenna directivity control completion signal, the antenna directivity indicating unit 113 recognizes that the directional antenna ANT is directed to the sector, and the terminal is included in the sector. Management information having presence confirmation information as to whether or not an ST is present is transmitted.

  And when the antenna directivity instruction | indication part 113 transmits the management information which has presence confirmation information, an Up link period is allocated and it waits for a response reply in the meantime.

  Here, the packet configuration of the management information transmitted from the access point AP to the terminal ST is shown in FIG. 4A, and an example of the packet type is shown in FIG. 4B. Note that the packet type table shown in FIG. 4B is held in common not only on the MAC unit 11 of the access point AP but also on the terminal ST side.

  As shown in FIG. 4A, the packet structure of the management information includes “packet type 201” indicating the management information, “source address (access point MAC address) 202”, “time allocation information 203 for each terminal ST. ”And“ Time information 204 next to the antenna ”. Further, the packet type shown in FIG. 4B is inserted into “packet type 201”.

  Returning to FIG. 3, the function of the wireless unit 12 will be described. The radio unit 12 gives the transmission data frame given from the MAC unit 11 to the antenna unit 13 in accordance with a modulation scheme according to a predetermined radio communication scheme. The radio unit 12 demodulates the radio signal received from the antenna unit 13 according to a predetermined radio communication method, and gives the demodulated data to the MAC unit 11. The radio unit 12 gives an antenna directivity control signal from the MAC unit 11 to the antenna unit 13. The radio unit 12 gives an antenna directivity control completion signal from the antenna unit 13 to the MAC unit 11.

  The antenna unit 13 controls the directivity of the directional antenna ANT under the control of the MAC unit 11. When the antenna unit 13 receives the antenna directivity control signal from the MAC unit 11 via the wireless unit 12, the antenna unit 13 switches the directivity of the directional antenna ANT to the sector included in the antenna directivity control signal. is there. In addition, the antenna unit 13 gives an antenna directivity control completion signal to the MAC unit 11 via the radio unit 12 in order to notify that when the directivity of the directional antenna ANT is switched.

(A-2) Operation of the First Embodiment Next, the operations of the time allocation management process and the antenna directivity control management process in the access point AP according to the first embodiment are shown in FIG. 1, FIG. 5, and FIG. Will be described with reference to FIG.

  FIG. 1 is an explanatory diagram for explaining time allocation management and antenna directivity control management in an access point AP. FIG. 5 is a flowchart showing the operation at the access point AP, and FIG. 6 is a flowchart showing the operation at the terminal ST.

  In the following, for example, a case where the access point AP manages eight different sectors (sector 1 to sector 8), and one-to-many wireless communication is possible across all directions in the eight sectors 1 to sector 8. Shown in the example.

  Both FIG. 1A and FIG. 1B show the arrangement of sectors 1 to 8 managed by the access point AP and the presence / absence of terminals ST in the respective sectors 1 to 8.

  In the figure, the terminal ST is indicated by a white circle. For example, one terminal ST exists in the sector 1 and the sector 3, and two terminals exist in the sector 2, for example. Further, it is assumed that no terminals ST exist in sectors 4 to 8. In the figure, the terminal ST displayed with a black circle represents a new entry terminal, and is assumed not to be recognized by the access point AP at present and to be recognized during the operation described later.

  First, the communication procedure by the access point AP will be described using the flowchart showing the time management allocation in FIG. 1C and the operation by the access point AP in FIG.

  First, referring to FIG. 1 (b), in the communication time domain, the access point AP selects an arbitrary sector from the sectors having the terminal ST that is performing radio communication, and a directional antenna in units of the sector. An operation for switching the ANT directivity will be described.

  In FIG. 5, the MAC unit 11 selects the sector having the terminal ST that is performing wireless communication as 1 (S101), and directs the antenna directivity “sector number 1” to direct the directional antenna ANT toward the sector 1. A sex control signal is transmitted to the antenna unit 13 (S102).

  The antenna unit 13 controls the directivity of the directional antenna ANT to the sector 1 according to the instruction of the MAC unit 11 based on the received antenna directivity control signal. Then, the antenna unit 13 transmits to the MAC unit 11 an antenna directivity control completion signal indicating that the antenna directivity control has been completed.

  When the MAC unit 11 receives the antenna directivity control completion signal from the antenna unit 13 (S103), the MAC unit 11 recognizes that the directivity of the directional antenna ANT is controlled by the sector 1, and controls the sector 1 with management information ( Packet type: PT = 1 in FIG. 4 is transmitted (S104).

  This management information describes time allocation information that can be transmitted by each terminal ST in the sector 1, and the terminal ST transmits according to the time allocation information included in the received management information. Thereby, time allocation can be performed for each terminal ST existing in the sector 1, and the terminal transmits according to the instruction of the access point AP, so that packet collision due to the hidden terminal state can be avoided.

  Both the access point AP and the terminal ST use directional antennas. In this case, it is assumed that the management information transmitted by the access point AP can be received only by the terminal ST1 existing in the sector 1.

  Next, in the access point AP, the MAC unit 11 transmits a Down link packet for the terminal ST1 to the terminal ST1 (S105).

  Further, when a predetermined Down link time ends after transmission of Down link (S106), the antenna unit 13 switches the directional antenna ANT from transmission to reception (S107). A predetermined time is required for the transmission / reception switching of the directional antenna ANT, and this time corresponds to the antenna transmission / reception switching time of FIG.

  Next, when the transmission / reception switching of the directional antenna ANT is finished, the directional antenna ANT enters the Up link reception state and receives a packet from the terminal ST1 (S108).

  At this time, as the packet types of the packets received from the terminal ST1, various types shown in FIG. 4 can be applied. For example, a disconnection request (PT = 4), an allocation time request (PT = 5), a data packet (PT = 7) Receives packets of the types Ack (PT = 8) and Nack (PT = 9).

  Thereafter, when a predetermined Up link time ends (S109), the antenna unit 13 switches the directional antenna ANT from transmission to reception (S110), and the access point AP completes wireless communication with the sector 1 (S111).

  Here, a random access area is provided during the Up link period of sector 1 in FIG. 1C, so that it can cope with the entry of a new terminal.

  For example, in FIG. 1C, when a new terminal ST6 enters, at present, the access point AP does not know the presence of the terminal ST6 and does not allocate a transmission available time to the terminal ST6. Therefore, the new entry terminal ST6 transmits an entry request (PT = 3) or an allocation time request (PT = 5) to the access point AP in this random access area, informs the access point AP of the existence, and allocates time. Can be requested.

  The random access area may be provided for each sector every time, or may be provided once every n times in order to improve communication efficiency. FIG. 1C shows an example in which only sector 1 is provided.

  As described above, the communication to the sector 1 by the access point AP is completed, and then the process returns to S101 to perform the communication process for the next sector to be selected. Here, it is assumed that the next sector 2 is selected in the communication time region.

  The MAC unit 11 transmits an antenna directivity control signal “sector number 2” to the antenna unit 13 (S101 and S102).

  When the antenna unit 13 controls the directivity of the directional antenna ANT to sector 2 in accordance with the antenna directivity control signal from the MAC unit 11, the antenna unit 13 transmits an antenna directivity control completion signal to the MAC unit 11.

  When the MAC unit 11 receives the antenna directivity control completion signal (S103), the MAC unit 11 transmits management information to the sector 2 (S104).

  The access point AP recognizes the presence of the terminal ST2 and the terminal ST3 in the sector 2, and performs Down link transmission to each of the terminal ST2 and the terminal ST3 (S105).

  At this time, the period of the Down link period is divided into the terminal ST2 and the terminal ST3 (see FIG. 1C).

  Thereafter, when a predetermined Down link time ends after transmission of the Down link (S106), transmission / reception switching of the directional antenna ANT is performed (S107), and the directional antenna ANT enters an Up link reception state (S108).

  Also in this case, as in the case of the Down link, the period of the Up link period is divided into the terminal ST2 and the terminal ST3 (see FIG. 1 (c)), and packets can be received from the respective terminals ST2 and ST3. To do.

  Thereafter, the processing of S109 to S111 is the same as that in the case of communication in sector 1, and thus detailed description thereof is omitted.

  As described above, communication to the sector 2 by the access point AP is completed, and the access point AP selects the sector 3 which is the next sector.

  The MAC unit 11 transmits an antenna directivity control signal indicating “sector number 3” to the antenna unit 13 (S101 and S102).

  When the antenna unit 13 controls the directivity of the directional antenna to the sector 3 in accordance with the antenna directivity control signal from the MAC unit 11, the antenna unit 13 transmits an antenna directivity control completion signal to the MAC unit 11.

  When receiving the antenna directivity control completion signal (S103), the MAC unit 11 transmits management information to the sector 3 (S104).

  The access point AP recognizes the presence of the terminal ST4 in the sector 3, and performs Down link transmission to the terminal ST4 (S105). When a predetermined Down link time ends after the transmission of Down link (S106), the antenna unit 13 performs directional antenna transmission / reception switching (S107).

  After that, the Up link reception state is set, and the access point AP receives a packet from the terminal ST4 (S108).

  Thereafter, the processing of S109 to S111 is the same as that in the case of communication in sector 1, and thus detailed description thereof is omitted.

  In the communication time region, the above-described communication for sector 1 to sector 3 is repeatedly performed.

  As described above, Down link and Up link are not performed for each terminal, but are performed in units of sectors. Thereby, the number of antenna transmission / reception switching can be reduced, and the access point AP can perform time allocation management in units of sectors.

  Further, in the communication time region shown in FIG. 1 (c), sector switching is basically repeated in the order of sector 1, sector 2, sector 3, sector 1, sector 2, sector 3,. , When the access point AP receives the allocation time request (PT = 5) from the terminal ST and by the down link information, the access point AP is timed as sector 1, sector 1, sector 2, sector 1, sector 1, sector 3,. It is also possible to change the allocation.

  Further, as described above, time allocation such as sector 1, sector 1, sector 2, sector 1, sector 1, sector 3,... Is enabled by an allocation time request from terminal ST and Down link data. Therefore, the access point AP does not set the maximum number of STs accommodated in units of sectors, but sets the maximum number of STs accommodated by the access point AP as a whole.

  Further, when there is no data to be transmitted from the terminal ST and there is no need for time allocation, a withdrawal request (PT = 4) is transmitted from the terminal ST. When the access point AP receives the leave request, the access point AP determines whether there is no Down link information for the terminal ST from the transmission buffer. If there is no Down link information, the access point AP performs leave permission, and Down link data. If there is, refuse to leave. A reply to the withdrawal request is added as information in the management information.

  In addition, the access point AP has a time-out function, and when the access point AP allocates time to the terminal ST, no packet is received from the terminal ST for a predetermined time. Can forcibly leave the access point AP.

  Next, the communication procedure by the terminal ST will be described with reference to the flowchart of FIG.

  First, when the management information transmitted from the access point AP is received, the management information is received (S201), and the Down link packet from the access point AP is received (S202).

  After that, when a predetermined Down link time ends (S203), the directional antenna is switched from reception to transmission (S204).

  Next, Up link information is transmitted to the access point AP (S205). When the predetermined Up link time ends (S206), the directional antenna is switched from transmission to reception (S207), communication for the sector is completed (S208), and the process returns to S201, and the next management information from the access point AP Await.

  In this embodiment, since the access point AP is fixed and installed, when the terminal ST searches for the access point AP at the initial time or when switching the network to another access point AP, the antenna directivity control is performed. However, since antenna directivity control is not required during communication with the same access point, the description is omitted here.

  Subsequently, referring to FIG. 1A, in the surrounding terminal confirmation time region, the access point AP selects an arbitrary sector from the sectors having the terminals ST that are performing wireless communication, and is directed in units of the sector. The operation of switching the directivity of the directional antenna ANT will be described.

  In sector 6 of FIG. 1A, terminal ST5 is a new entry terminal, and access point AP does not perform time allocation to terminal ST.

  First, in the access point AP, the MAC unit 11 selects “sector number 4” (S101), and transmits an antenna directivity control signal indicating “sector 4” to the antenna unit 13 (S102).

  When the antenna unit 13 controls the directivity of the directional antenna ANT to the sector 4 in accordance with the instruction based on the antenna directivity control signal from the MAC unit 11, the antenna directivity control completion signal that indicates that the antenna directivity control is completed. Is transmitted to the MAC unit 11.

  When receiving the antenna directivity control completion signal from the antenna unit 13 (S103), the MAC unit 11 transmits management information for the peripheral terminal confirmation time (PT = 2 in FIG. 4) toward the sector 4 (S104 and S105). In this case, the Down link information is only management information.

  When the management information is transmitted and a predetermined Down link time is finished (S106), the antenna unit 13 switches the directional antenna ANT from transmission to reception (S107) so that the Up link information can be received (S108).

  At this time, since the MAC unit 11 of the access point AP cannot receive any information in the Up link period for the sector 4 (S109), the MAC unit 11 of the access point AP has no terminal ST in the sector 4, It is determined that there is no need to allocate time, the directional antenna is switched from reception to transmission (S110), communication in sector 4 is completed (S111), and sector 5 is then selected.

  Here, since the communication process for the sector 5 by the access point AP is the same as that for the sector 4, the description here is omitted, and the communication process for the sector 6 selected next to the sector 5 will be described.

  When selecting “sector number 6” (S101), the MAC unit 11 of the access point AP transmits an antenna directivity control signal indicating “sector number 6” to the antenna unit 13 (S102).

  When the antenna unit 13 controls the directivity of the directional antenna ANT to the sector 6 in accordance with the instruction based on the antenna directivity control signal from the MAC unit 11, the antenna directivity control completion signal that indicates that the antenna directivity control is completed. Is transmitted to the MAC unit 13.

  When receiving the antenna directivity control completion signal from the antenna unit 13 (S103), the MAC unit 11 transmits management information for the surrounding terminal confirmation time region (PT = 2 in FIG. 4) toward the sector 6 (S104). And S105). In this case, the Down link information is only management information.

  When the Down link information is transmitted and a predetermined Down link time is finished (S106), the antenna unit 13 switches the directional antenna ANT from transmission to reception (S107) so that the Up link information can be received from the sector 6. (S108).

  At this time, it is assumed that a newly entering terminal ST5 enters the sector 6. The terminal ST5 transmits a packet having an entry request (PT = 3) to the access point AP as Up link information during the Up link period.

  When the access point AP receives the entry request from the terminal ST5, the access point AP recognizes that the new terminal ST5 exists in the sector 6, and adjusts time allocation for the sector 6 in the next communication time region.

  The access point AP transmits a packet having a response to the entry request from the terminal ST toward the sector 6 as management information in the next communication time region.

  Thereafter, when a predetermined Up link time ends (S109), the directional antenna ANT is switched from reception to transmission (S110), and communication with the sector 6 is completed (S111).

  After the communication with the sector 6 is completed, the communication process with respect to the sector 7 and the sector 8 is the same as the communication process with respect to the sector 4, and it is determined that the terminal ST does not exist and the process without performing the time allocation is performed. The detailed explanation is omitted.

  The random access area is only the random area in the surrounding terminal confirmation time area and the communication time area, and the other areas are managed by the access point AP for the time of the terminal ST and do not cause packet collision. Tension type access control.

  Therefore, the existence process of a new terminal is performed in the surrounding terminal confirmation time area, and the entry process to the network can be performed by random access control in the communication time area.

  In this way, by dividing the time domain into two, the access point AP can concentrate on communication in the communication time domain, and packets received in the random access domain and packets that are transmitted and received in the communication domain and packet collisions. It does not cause.

  In addition, when a plurality of terminals ST happen to transmit at the same time, there is a possibility of packet collision. Therefore, packet collision avoidance can be performed by slotting the random access control area and allowing the terminal ST to randomly select which slot to use.

  In the present embodiment, in FIG. 1, the surrounding terminal confirmation is performed only in the sector where there is no time-assigned terminal ST. However, when the traffic is low and there is free time, Peripheral terminal confirmation may be performed.

  Further, by checking the surrounding terminals for all sectors, when a new terminal ST enters the communicating sector, the access point AP recognizes the presence of the terminal ST in this surrounding terminal checking time region. be able to. Communication efficiency can be improved by checking the surrounding terminals only in a sector where there is no time-assigned terminal ST.

  Then, with reference to FIG. 2, the whole antenna directivity control process in the radio | wireless communications system NT of this embodiment is demonstrated.

  FIG. 2 shows the case where the access point AP has ST1 in the sector 1, ST2 and ST3 in the sector 2, ST4 in the sector 3, and ST5 in the sector 6, and the terminal ST can move to another sector. is there.

  In this case, since the sectors are different, the terminal searches for an access point again after movement.

  When ST5 moves from sector 6 to sector 8, the access point AP deletes ST5 time allocation for sector 6 and allocates ST6 time for sector 8.

  As an operation procedure in this case, first, the terminal ST5 communicates with the access point AP as a terminal existing in the sector 6. At this time, the access point AP is communicating with the terminal ST5 in communication with the sector 6 in the communication time domain.

  Thereafter, when the terminal ST5 moves from the sector 6 to the sector 8, the access point AP deletes the time allocated to the terminal ST5 in the sector 6.

  That is, in communication with sector 6, during the Up link period, the access point AP receives a packet having a withdrawal request (PT = 4) from the terminal ST5 or does not receive a packet within the Up link period. By determining that it has left, the time for the terminal ST5 in the sector 6 is deleted.

  Terminal ST5 performs access point AP search. That is, in this case, since the access point AP is communicating with the sector 8 in the surrounding terminal confirmation time region, when the terminal ST5 receives the management information (PT = 2) packet from the access point AP in the sector 8, A packet having a participation request (PT = 3) is transmitted to the access point AP for entry.

  As a result, the access point AP can allocate time to the terminal ST5 in the sector 8, determines whether or not new entry is permitted, and transmits management information to the sector 8. When the entry is permitted, the terminal ST5 communicates with the access point AP, and when the entry is refused, the terminal ST5 searches for another access point AP.

(A-3) Effect of First Embodiment As described above, according to the first embodiment, the MAC unit 11 performs antenna directivity control management, so that even if a directional antenna is used, different communication areas are used. Can communicate with a plurality of terminals existing in the network, and the communication area of the access point can be expanded.

  In addition, according to the first embodiment, centralized control is performed on a plurality of communication areas and a plurality of terminals having different access points, and the terminals can use the management information transmitted from the access points to use the time available to the terminals. To inform. As a result, even if there are multiple terminals in multiple communication areas, communication with the access point is possible even if the communication status between the terminals cannot be confirmed with each other. Quality degradation can be suppressed.

  Furthermore, according to the first embodiment, a plurality of terminals are provided in a sector by performing Down link communication and Up link communication in units of sectors, instead of performing Down link communication and Up link communication in units of terminals. Is present, the redundancy time is reduced by reducing the number of antenna transmission and reception switching.

  Further, according to the first embodiment, a terminal can newly enter the network by providing an area where the access point AP confirms surrounding terminals in an area where communication is not currently performed. .

  Furthermore, according to the first embodiment, the MAC part of the access point has a random area time length in the communication area according to the reply status in the surrounding terminal confirmation time area and the reply status in the random access area in the communication area. Change the size to reduce the time not to use even if the access point is assigned.

  In addition, according to the first embodiment, it is possible to communicate with a plurality of terminals existing in different communication areas using millimeter wave communication and a directional antenna, and using millimeter wave communication with an expanded communication area, High-speed transmission communication is possible.

(B) Second Embodiment Next, a second embodiment of the wireless transmission device, wireless station, wireless terminal, and wireless transmission system of the present invention will be described with reference to the drawings.

  In the second embodiment, a sector management method when a plurality of access points AP are provided will be described.

  Since the time allocation management process for each access point is the same as that in the first embodiment, a detailed description of the time allocation management process is omitted in the second embodiment.

  7 and 8 are explanatory diagrams for explaining sector management when there are two access points. FIG. 9 is a block diagram showing an internal configuration of the access point AP according to the second embodiment.

  FIG. 7 shows a case where two access points AP are installed close to each other, and FIG. 8 shows an example where two access points AP are installed apart from each other.

  First, with reference to FIG. 7, the sector management of the access point AP when the access point AP is installed close will be described.

  In FIG. 7, the access point AP1 communicates with the terminals ST belonging to the sectors 2 to 5, and allocates time to the sector 2, sector 3 and sector 5 in the communication time domain. Time is allocated to sector 4 in the terminal confirmation time area.

  On the other hand, the access point AP2 communicates with the terminals ST belonging to the sectors 6 to 8 and the sector 1, and allocates time to the sectors 6, 8 and 1 in the communication time region. In the surrounding terminal confirmation time area, time is allocated to the sector 7.

  At this time, when the access points AP1 and AP2 perform communication while performing antenna directivity control, in order to prevent interference between the access points, for example, ARP (Address Resolution Protocol) table information, The routing table information and the terminal ST information belonging to the sector are exchanged, and the sector management in charge is matched.

  Therefore, each access point AP1 and AP2 has inter-AP communication means for connecting between the access points AP1 and AP2 via a wired line or a wireless line.

  As shown in FIG. 9, the MAC units 11 of the respective access points AP1 and AP2 have the ARP table information and the routing table received via the inter-AP communication means in addition to the configuration described in the first embodiment. Based on the information and the terminal ST information belonging to each sector, a sector management adjustment unit is provided that adjusts the sector in charge of each.

  For example, it is assumed that sector management is performed between the access points AP1 and AP2 to achieve matching as shown in FIG.

  Thereafter, in the access point AP1, when the amount of information transmitted to the terminals ST existing in the sector 2 and the sector 3 increases, between the access points AP1 and AP2, the ARP table information, the routing table information, and the terminals belonging to each sector The ST information is exchanged and the sector management adjustment is performed.

  In this case, for example, the MAC unit 11 of the access point AP1 has a buffer for buffering information for the terminals ST in the sector 2 and the sector 3, and when the buffer amount exceeds a predetermined threshold, Sector management adjustment may be performed. Note that the amount of information at this time may be Down link information or Up link information.

  As a result, the access points AP can be matched again. The access point AP1 is responsible only for the sectors 2 and 3, and the access point AP2 is responsible for the remaining sectors. Is effectively used.

  Next, sector management by the access point AP when the two access points AP are set apart from each other will be described with reference to FIG.

  The internal configuration of the access point AP in this case is the same as that described with reference to FIG. 7, and detailed description thereof is omitted.

  In FIG. 8, the access point AP1 is responsible for sectors 1 to 4 and the access point AP2 is responsible for sectors 5 to 8 depending on the installation location.

  Note that the configuration, the number of sectors, and the number of APs shown in this embodiment are merely shown as examples, and the present invention is not limited to this.

(B-3) Effects of Second Embodiment As described above, according to the second embodiment, the same effects as those of the first embodiment can be obtained.

  Further, according to the second embodiment, by dividing the assigned sector among a plurality of access points AP, time division and space division for the terminal ST can be performed, and communication efficiency can be improved.

(C) Third Embodiment Next, a third embodiment of the wireless transmission device, wireless station, wireless terminal, and wireless transmission system of the present invention will be described with reference to the drawings.

  In the third embodiment, an access point search process in a newly entering terminal ST will be described.

  Note that the time allocation management processing by the access point AP and the directivity control processing of the directional antenna can correspond to the same processing as described in the first and second embodiments. In the third embodiment, for convenience of explanation, a case where the access point AP described in the first embodiment is applied will be described as an example.

  In the third embodiment, as described above, a new terminal ST enters a sector where no terminal has existed until then, and an access point search process by the new terminal ST will be described.

  The access point AP communicates with the sector in the surrounding terminal confirmation time region for the sector whose terminal existence has not been confirmed. When the new terminal ST enters this sector, the terminal ST has directivity. By using the antenna to receive management information from the access point AP, the location of the access point is searched.

  For example, in FIG. 10, when the sum of the surrounding terminal confirmation time area and the communication time area is T time, when the new entry terminal ST5 receives management information from the access point AP, it means that it has searched the position of the access point. If terminal ST5 performs an access point search for all directions, 8T time is required.

  Therefore, a method of searching for this access point in a short time and without affecting the communication between the terminal and the access point existing in sectors 1 to 3 will be described.

(C-1) Configuration of Third Embodiment FIG. 11 is an overall configuration diagram showing a configuration of a wireless communication system NT of the third embodiment. In FIG. 11, an access point AP and five terminals ST1 to ST5 are shown.

  Reference numeral 307 denotes a communication area of the access point AP, and reference numerals 308, 309, 310, and 311 denote sector 1, sector 2, sector 3, and sector 6, which are communication areas viewed from the access point AP.

  FIG. 12 is a block diagram showing an internal configuration of the access point AP, and FIG. 13 is a block diagram showing an internal configuration of the terminals ST1 to ST5. Since terminals ST1 to ST5 have the same internal configuration, these terminals will be described as representative terminals ST.

  As for the internal configuration of the access point AP, in addition to the internal configuration shown in FIG. 3 described in the first embodiment, the antenna unit 13 includes a carrier signal transmission omnidirectional antenna 312 and a one-to-one communication directional antenna. 313 and two types of antennas.

  The one-to-one communication directional antenna 313 corresponds to the directional antenna ANT of the first embodiment, and a description of the function of the antenna 131 including the MAC unit 11 and the antenna unit 13 is omitted.

  The carrier signal transmission omnidirectional antenna 312 transmits a carrier signal with no signal information on it at a predetermined period under the control of the antenna unit 13. The carrier signal transmitted by the omnidirectional antenna 312 for transmitting a carrier signal is repeatedly transmitted at a predetermined cycle at least in the communication time region, and the transmission cycle is at least the number of sectors managed by the access point AP in the communication time region. To be able to send

  FIG. 13 is a block diagram showing an internal configuration of terminal ST (ST1 to ST5). As illustrated in FIG. 13, the terminal ST includes a MAC unit 21, a radio unit 22, and an antenna unit 23. The antenna unit 23 includes a carrier signal receiving directional antenna 314, a one-to-one communication directional antenna 315, and the like. There are two types of antennas.

  The one-to-one communication directional antenna 315 corresponds to the directional antenna ANT of the first embodiment, and a description of the function thereof is omitted.

  The carrier signal receiving directional antenna 314 receives a carrier signal transmitted by the access point AP at a predetermined period.

  The antenna unit 23 controls the directivity of the carrier signal receiving directional antenna 314 and the one-to-one communication directional antenna 315. In addition, the antenna unit 23 includes a reception power measurement unit 231 that measures the reception power of the carrier signal received by the carrier signal reception unit 314. The received power measuring unit 231 associates the measured received power value of the received carrier signal with the sector number to which the carrier signal receiving directional antenna 314 is directed at that time, and transmits it to the MAC unit 21 via the wireless unit 22. The sector number and the received power value are stored in the MAC unit 21 in association with each other.

  Since the wireless unit 22 has the same function as the wireless unit 12 of the access point AP, detailed description thereof is omitted.

  The MAC unit 21 performs transmission control in the radio communication system NT, and includes a media access control unit 211, a carrier signal received power value storage unit 212, and a terminal-side antenna directivity instruction unit 13.

  Since the media access control unit 211 has the same function as the media access control unit 111 of the access point AP, detailed description thereof is omitted.

  The carrier signal received power value storage unit 212 stores the sector number and the received power value received from the antenna unit 23 via the radio unit 22 in association with each other.

  The terminal-side antenna directivity instruction unit 13 controls the directivity of the carrier signal receiving directional antenna 314. In the present embodiment, control is performed so that the sectors managed by the terminal ST are switched in a predetermined order such as sector 1, sector 2,.

  The terminal-side antenna directivity indicating unit 13 detects a sector having a received power value equal to or higher than a predetermined specified value among the received power values stored in the carrier signal received power value storage unit 212.

  Thereby, since only the access point AP is transmitting the carrier signal, it can be searched that the access point AP exists in the sector whose reception power value is equal to or greater than the predetermined specified value.

  When there are a plurality of access points AP, a plurality of received power values that are equal to or greater than a prescribed value may be detected. In this case, the terminal-side antenna directivity instruction unit 13 may select the largest received power value among the plurality of specified values or more.

  In addition, when the terminal-side antenna directivity instruction unit 213 detects a sector having a received power value equal to or greater than a predetermined specified value, the antenna directivity control signal so that the one-to-one communication directional antenna 315 is directed in the sector direction. Is given to the antenna unit 23 via the radio unit 22. Then, the antenna unit 23 controls the directivity of the one-to-one communication directional antenna 315 so as to face the designated sector direction based on the antenna directivity control signal.

  Accordingly, since the one-to-one communication directional antenna 315 can be directed in advance to the sector where the access point AP exists, the Down link information (management information) transmitted from the access point AP to the surrounding terminal confirmation time region. ) Can be requested for entry. In other words, where an access point search takes 8T hours, it can be performed within T hours.

(C-2) Operation of Third Embodiment Next, the access point AP search processing by the terminal ST according to the third embodiment will be described with reference to the drawings.

  In FIG. 12, the access point AP controls the directivity of the one-to-one communication directional antenna 313, and separates the communication for each sector, and sets the carrier signal transmission omnidirectional antenna 312 in a predetermined cycle. It is used to transmit a carrier signal without signal information.

  The terminal ST5 is a terminal that newly enters the sector 6, and is a terminal that tries to search for the position of the access point AP. Here, FIG. 14 is a flowchart showing an operation in the terminal ST.

  The new terminal ST5 that has entered the sector 6 selects a certain sector among the sectors viewed from the terminal ST5 (S301), and switches the directional antenna 314 for receiving a carrier signal to the sector.

  Here, FIG. 15 shows a sector state diagram 401 viewed from the access point AP and sector state diagrams 402 to 407 viewed from the terminal ST5, and the access point AP is located in the sector 6 viewed from the terminal ST5. Suppose it exists.

  First, terminal ST5 selects sector 1 and switches directional antenna 314 for receiving a carrier signal to sector 1, as shown in state diagram 402. Then, when the carrier signal receiving directional antenna 314 receives the carrier signal, the received power value measuring unit 231 measures the received power value of the received carrier signal (S302).

  The received power value of the carrier signal is stored in the carrier signal received power value storage unit 212 of the MAC unit 21 in association with the sector number (S303).

  In some cases, the reception of the carrier signal cannot be detected. In this case, the next sector is selected (S301), the carrier signal receiving directional antenna 314 is switched, and the same processing is performed for the next sector. To do.

  Further, when the received power value of the carrier signal is not measured for other sectors, the next sector is selected (S301).

  Here, when sector 1 is completed, the received power value of the carrier signal of sector 2 is measured and stored as shown in state diagram 403, and then sector 3 (state diagram 404), sector 4 (state diagram 405), Sector 5 (state diagram 406), sector 6 (state diagram 407),... Are sequentially switched to perform the same processing.

  Since the wireless device transmitting the carrier signal is only the access point AP, when the terminal ST5 detects a received power value equal to or higher than a predetermined default value (S305), the terminal ST5 recognizes that the sector has the access point AP. The access point search unit 213 stores the sector number 6 and controls to direct the one-to-one communication directional antenna 315 toward the sector 6 (S306). Thereby, it is possible to wait for existence confirmation from the access point AP.

  By doing so, the new terminal can recognize the direction in which the access point exists.

  As described above, the access point AP uses the carrier signal so that it is not necessary to transmit / receive communication data.

  Further, in order to be able to cope with a plurality of access points, that is, without causing a problem of packet collision, the new terminal can recognize the direction in which the access point exists.

  Further, the new terminal can search the direction of the access point within the time T, and make the access point recognize the presence of the own station by the access point.

  In addition, the access point AP can search for an access point within T time period by transmitting a carrier signal having the number of sectors or more in a predetermined period in the communication time region at a predetermined period.

(C-3) Effects of the Third Embodiment As described above, according to the third embodiment, the same effects as those of the first and second embodiments can be obtained.

  Further, according to the third embodiment, the terminal searches for an access point by using the surrounding terminal confirmation time region a plurality of times, and the terminal detects the presence of the access point in one communication region, and once In the surrounding terminal confirmation time area, the terminal can notify the access point of the presence.

  Further, according to the third embodiment, it is possible to search for an access point without the need for performing complicated arithmetic processing as in the arrival wave estimation method described in Patent Document 2. Further, unlike the radio wave arrival direction estimation device, the radio wave arrival direction estimation method, and the directivity variable transmission / reception device described in Patent Document 3, it is not necessary to prepare as many receivers as the number of array antennas.

  Furthermore, according to the third embodiment, in order for the access point AP and the terminal ST to communicate using a directional antenna and to communicate with different communication areas, the terminal can be connected in a short time, In addition, it is possible to easily estimate the orientation of the access point and enter the network at an early stage.

(D) Fourth Embodiment Next, a fourth embodiment of the wireless transmission device, the wireless station, the wireless terminal, and the wireless transmission system of the present invention will be described with reference to the drawings.

(D-1) Configuration and Operation of Fourth Embodiment The fourth embodiment also describes a method in which a newly entered terminal ST searches for the position of the access point AP.

  In the fourth embodiment, as in the third embodiment, the terminal ST searches for the orientation of the access point AP based on the received power value of the carrier signal from the access point AP. The method for narrowing the azimuth is different from the third embodiment.

  Since the time allocation management processing and antenna directivity control management processing of the access point AP of the fourth embodiment are the same as those described in the first and second embodiments, detailed description thereof is omitted here.

  Also, the internal configurations of the access point AP and the terminal ST are different from the third embodiment in the functions of the directional antenna 314 for receiving a carrier signal and the antenna unit 23 for controlling the directivity, and the other functional configurations are the first. This is the same as the third embodiment. Therefore, the following description will be made with reference to FIGS.

  The directional antenna 314 for receiving a carrier signal according to the present embodiment can have a receiving range in which a carrier signal can be received, that is, a plurality of sectors can be received. In addition, the carrier signal reception directional antenna 314 of the present embodiment can change the number of reception sectors and the sector number as receivable areas.

  Further, the antenna unit 23 of this embodiment instructs the directivity of the carrier signal reception directivity antenna 314 based on the carrier signal reception power value and the sector information thereof.

  FIG. 16 shows a sector state diagram 501 viewed from the access point AP of this embodiment, and sector state diagrams 502 to 507 viewed from the newly entering terminal ST5. The sector 6 viewed from the terminal ST5 is shown in FIG. It is assumed that an access point AP exists.

  FIG. 17 is a flowchart showing an operation in the terminal ST5.

  First, as shown in the state diagram 502 in FIG. 16, the terminal ST5 selects the sector 1 to the sector 8 (S401), directs the directional antenna 314 for receiving carrier signals in all directions, and carries carrier signals in all directions. The received power for is measured (S402).

  Since the carrier signal is received in all directions as described above, it can be recognized that the access point AP exists if a carrier signal exceeding a specified value can be obtained.

  Next, as shown in the state diagram 503 of FIG. 16, the terminal ST5 halves the number of sectors for which the carrier signal receiving directional antenna 314 measures the received power value (S403).

  Also at this time, the terminal ST5 can similarly detect the reception power exceeding the predetermined value and recognize that the access point AP exists in the four sectors (S404 and S405).

  Furthermore, the terminal ST5 further halves the number of sectors for measuring the received power value of the carrier signal (S403), as shown in the state diagram 504 of FIG.

  In this case, since there is no access point AP in the range in which the received power value of the carrier signal is measured (S404), the measured received power value is equal to or lower than the predetermined value, and the sector shown in the state diagram 504 of FIG. 16 is accessed. Recognize that there is no point AP.

  Therefore, the terminal ST5 selects the sector group shown in the state diagram 505 in FIG. 16 opposite to the sector group selected in the state diagram 504 in FIG. 16 (S406), switches, and measures the received power value of the carrier signal To do.

  Then, the terminal ST5 can measure the received power value of the carrier signal, and further reduces the number of sectors for measuring the received power value of the carrier signal by half to narrow down to the direction of the sector 6 finally. It can be recognized that an access point exists (S405 and S407).

(D-3) Effects of the Fourth Embodiment As described above, according to the fourth embodiment, the same effects as those of the first to third embodiments can be obtained.

  Further, according to the fourth embodiment, by searching for the access point AP by gradually narrowing the azimuth range to be searched from all directions, when there are a large number of sectors covering all the directions, the sector 1 is sequentially set. Compared to the case of searching one by one, the number of searches can be reduced, and the time until the access point search can be shortened.

(E) Other Embodiments In the first to fourth embodiments, the wireless communication system adopting the centralized control type MAC system having the antenna directivity control function has been described as an example. However, it can also be applied to a high-speed wireless transmission device used indoors.

  In the second embodiment, the case where two access points AP are arranged has been described. However, as in the second embodiment, the present invention can be applied to a high-speed wireless transmission apparatus used indoors, and further, time division In addition, space division is possible, and communication efficiency can be increased.

  In the third and fourth embodiments, the example in which the access point AP of the first embodiment is used has been described. However, the present invention can also be applied to the case where the access point described in the second embodiment is used. .

It is explanatory drawing explaining the time allocation management and antenna directivity control management in the access point of 1st Embodiment. 1 is an overall configuration diagram of a wireless communication system according to a first embodiment. It is a block diagram which shows the internal structure of the access point of 1st Embodiment. It is explanatory drawing explaining the packet type of 1st Embodiment. It is a flowchart which shows the operation | movement in the access point of 1st Embodiment. It is a flowchart which shows the operation | movement in the terminal of 1st Embodiment. It is explanatory drawing explaining the time allocation management and antenna directivity control management in the access point of 2nd Embodiment. It is explanatory drawing explaining the time allocation management and antenna directivity control management in the access point of 2nd Embodiment. It is a block diagram which shows the internal structure of the access point of 2nd Embodiment. It is explanatory drawing explaining the time allocation management and antenna directivity control management in the access point of 3rd Embodiment. It is a block diagram which shows the structure of the access point and terminal of 3rd Embodiment. It is a block diagram which shows the internal structure of the access point of 3rd Embodiment. It is a block diagram which shows the internal structure of the terminal of 3rd Embodiment. It is a flowchart which shows the operation | movement in the terminal of 3rd Embodiment. It is a sector diagram which the access point and terminal of 3rd Embodiment manage. It is a sector diagram which the access point and terminal of 4th Embodiment manage. It is a flowchart which shows the operation | movement in the terminal of 4th Embodiment.

Explanation of symbols

  AP ... access point, ST (ST1 to ST5) ... terminal, NT ... wireless communication system, 11 ... MAC unit, 111 ... media access control unit, 112 ... time allocation management unit, 113 ... antenna directivity instruction unit, 114 ... sector Management adjustment unit, 12 ... radio unit, 13 ... antenna unit, ANT ... directional antenna, 312 ... omnidirectional antenna for carrier signal transmission, 313 ... directional antenna for one-to-one communication, 21 ... MAC unit, 211 ... media Access control unit, 212 ... carrier signal received power value storage unit, 213 ... terminal side antenna directivity instruction unit, 22 ... radio unit, 23 ... antenna unit, 231 ... received power measuring unit, 314 ... directional antenna for receiving carrier signal 215... One-to-one communication directional antenna.

Claims (11)

In a wireless transmission device of a wireless station that has a directional antenna and wirelessly communicates with one or more wireless terminals,
Managing the communication timing of each of the wireless terminals, and when the communication timing of each of the wireless terminals is reached, a control signal is given to each of the corresponding wireless terminals, and time management means for executing communication with the wireless terminal;
Directivity indicating means for instructing the directivity of the directional antenna for each of a plurality of divided communication areas obtained by dividing the communication area,
A radio transmission apparatus comprising: directional antenna control means for controlling the directivity of the directional antenna in accordance with a directivity instruction from the directivity instruction means.   The time management means allocates a communication time area allocated to the divided communication area where the existence of the wireless terminal is confirmed, and a terminal exists for the divided communication area where the existence of the wireless terminal is not confirmed. 2. The radio transmission apparatus according to claim 1, wherein time management is performed separately for a terminal presence confirmation time region assigned for confirmation.   The radio transmission apparatus according to claim 2, wherein the time management means performs time management for each of the divided communication areas in the communication time area and the terminal presence confirmation area.   The communication time area has a random access area for confirming the existence of a new terminal in the divided communication area where the existence of the wireless terminal is confirmed. The wireless transmission device described.   The wireless transmission according to any one of claims 1 to 4, further comprising communication area adjustment means for adjusting the divided communication area shared with other wireless stations by time division and / or space division. apparatus. In a radio transmission apparatus that performs radio communication with a directional antenna for intermittent signal reception that receives the signal transmitted by a radio station that transmits an intermittent signal, and a directional antenna for communication,
A communication antenna directivity indicating means for instructing the directivity of the data communication directional antenna based on the received power of the signal received by the intermittent signal receiving directional antenna;
A radio transmission apparatus comprising: a communication directional antenna directivity control unit that controls directivity of the communication directional antenna in accordance with an instruction from the communication antenna directivity instruction unit.   The communication antenna directivity instruction means instructs the directivity of the communication antenna based on a reception power result of the signal measured for each of a plurality of divided communication areas obtained by dividing the communication area into a plurality of divisions. The wireless transmission device according to claim 6.   After the communication antenna directivity indicating means receives the signal with the directivity of the intermittent signal receiving directional antenna as a whole range, a signal from the intermittent signal receiving directional antenna is obtained according to the reception power result of the signal. The wireless transmission device according to claim 6 or 7, wherein the directivity of the communication antenna is instructed by narrowing a measurement area according to a predetermined rule. In a wireless station having a directional antenna and wirelessly communicating with one or more wireless terminals,
A wireless communication means for wirelessly communicating with each of the wireless terminals;
A wireless station comprising: the wireless transmission device according to claim 1. In a wireless terminal that performs wireless communication with an intermittent signal receiving directional antenna that receives the signal transmitted by the wireless station that transmits the intermittent signal, and a communication directional antenna,
Wireless communication means for performing wireless communication with the wireless station;
A wireless terminal comprising: the wireless transmission device according to claim 6. A radio transmission system comprising one or more radio stations according to claim 10 and one or more radio terminals according to claim 11.

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