WO2014013560A1 - Wireless communication system, wireless communication base station, and wireless communication terminal - Google Patents

Wireless communication system, wireless communication base station, and wireless communication terminal Download PDF

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Publication number
WO2014013560A1
WO2014013560A1 PCT/JP2012/068142 JP2012068142W WO2014013560A1 WO 2014013560 A1 WO2014013560 A1 WO 2014013560A1 JP 2012068142 W JP2012068142 W JP 2012068142W WO 2014013560 A1 WO2014013560 A1 WO 2014013560A1
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communication
signal
base station
terminal
time slot
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PCT/JP2012/068142
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French (fr)
Japanese (ja)
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水垣　健一
宮崎　祐行
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株式会社日立製作所
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Priority to PCT/JP2012/068142 priority Critical patent/WO2014013560A1/en
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W72/00—Local resource management
    • H04W72/04—Wireless resource allocation
    • H04W72/044—Wireless resource allocation based on the type of the allocated resource
    • H04W72/0446—Resources in time domain, e.g. slots or frames
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W84/00—Network topologies
    • H04W84/18—Self-organising networks, e.g. ad-hoc networks or sensor networks

Definitions

  • the present invention relates to a wireless communication system, a wireless communication base station, and a wireless communication terminal, and more particularly to a wireless communication system (device) that performs communication via a plurality of terminals as wireless relay stations.
  • control information can be transmitted wirelessly, the cost can be greatly reduced.
  • Such control information is required to be transmitted without error in a short delay time, because if the instruction timing is delayed, the machine may malfunction or run away.
  • the conventional wireless communication method is suitable for short-delay communication.
  • the TDMA Time Division Multiple Access
  • the TDMA is used to share a short time unit called a time slot in synchronization with the entire system, and to specify a terminal to communicate for each time slot. It was a method.
  • a base station that manages time slot allocation is provided to a base station and all terminals on the ad hoc communication path.
  • multiple consecutive time slots are allocated together as one large time slot, in which the conventional time slot framework is ignored and a signal is received immediately (ie, “immediately”) to the next destination. Repeat the signal transfer.
  • ad hoc network in a TDMA ad hoc network, it is possible to reduce transmission delay caused by communication from a transmission source to a destination without changing the width of a time slot. Further, since the present invention does not affect communications other than ad hoc communication, transmission delay of ad hoc communication can be reduced within the framework of a conventional TDMA communication system.
  • transmission / reception of control information from the base station to the terminal is assumed, but the present invention can also be applied to data communication in which data measured by the terminal in response to a request from the base station is transmitted to the base station. Furthermore, the present invention can also be applied to communication from terminal to terminal.
  • Fig. 1 shows the system configuration of this embodiment.
  • time slots are managed and a base station (100) that transmits control information to a terminal and a plurality of base stations (100) that are connected to sensors and machine tools to transmit and receive data.
  • Terminal (201 to 206).
  • the base station can be connected to a network (300) such as a wide area network.
  • a network such as a wide area network.
  • multi-hop communication it does not depend on the network configuration.
  • a cluster tree configuration in which communication is performed from the base station to the terminal and the terminal returns a response to the base station will be described.
  • the communication method used in this system is TDMA.
  • the TDMA time slot is managed and allocated by the base station.
  • the configuration of the base station (100) is shown in FIG.
  • the base station has a time slot management function unit (101) that manages time slots in the system, and a network configuration database unit (DB) (102) that records information related to the network configuration in the system.
  • DB network configuration database unit
  • a system synchronization function unit (103) for controlling time synchronization in the system and a data communication function unit (or “data transmission / reception function unit”) (104) for managing data transmission / reception with the terminal are provided.
  • Signal transmission / reception required from these functions becomes a radio signal through the radio communication function unit (105) and is transmitted / received from the antenna (106).
  • the base station has a wide area communication interface (IF) (107), and can connect to the wide area network (300) to transmit and receive information.
  • IF wide area communication interface
  • FIG. 1 The configuration diagram of the terminal (200) of this system is shown in FIG.
  • the terminal has a synchronization maintaining function unit (211) that maintains synchronization with the system time and a system information memory (212) that stores information on the system configuration notified from the base station.
  • the terminal has a data transmission / reception function unit (213) for transmitting / receiving data to / from the base station and other terminals.
  • Signal transmission / reception required from these functions becomes a radio signal through the radio communication function unit (214) and is transmitted / received from the antenna (215).
  • the terminal is connected to an external device (217) such as a sensor or a machine tool through an external interface unit (IF) (216) to send control information and send information obtained therefrom to a base station or another terminal. can do.
  • IF external interface unit
  • FIG. 4 shows the structure of a normal time slot (400) used in TDMA used in this system.
  • the transmission side performs packet transmission (402) after transmission offset (401) has elapsed from the beginning of the time slot.
  • This transmission offset (401) is for absorbing a synchronization error between the system times of the transmission side and the reception side.
  • the transmission side starts reception preparation (403) after transmitting the packet (421), and then waits for Ack from the reception side (404).
  • the Ack signal (422) transmitted / received here confirms signal reception in the Mac layer, it will be referred to as the Mac layer Ack hereinafter.
  • the transmission side can receive (405) the Mac layer Ack (422), the communication is completed. If the Mac layer Ack (422) cannot be received, it is determined that communication has failed.
  • the reception side starts a packet reception standby (412) after a reception offset (411) which is a waiting time corresponding to the transmission offset (401).
  • a reception offset 411) which is a waiting time corresponding to the transmission offset (401).
  • the packet content is confirmed, and if there is no problem, the Mac layer Ack (422) is prepared (414). Thereafter, the Mac layer Ack (422) is transmitted to the terminal (415).
  • FIG. 5 shows a configuration example of a TDMA superframe (500) used in this system.
  • the superframe is a repetition cycle of assigning the time slot (400) (see FIG. 4) to the terminal (200) / base station (100), and is composed of a plurality of time slots.
  • the super frame (500) includes a normal slot (501) used for normal communication and a retransmission slot (502) that performs signal retransmission when communication fails in the normal slot.
  • the normal slot is used for both data communication between the terminal and the base station and signal transmission for maintaining synchronization.
  • the base station transmits data to each terminal at every data transmission interval (503). This data transmission interval is a constant multiple of the superframe.
  • the time slot (400) is managed by the base station (100), and the terminal (200) and the base station (100) that communicate with each time slot and the communication channel to be used are designated in advance. For normal communication, one terminal or base station on the transmitting side and one on the receiving side is allocated to one time slot (400). Information about time slot designation is sent from the base station (100) to the corresponding terminal (200). If the terminal (200) does not move, the operator may set information related to time slot designation directly in advance to each terminal or base station.
  • a time slot (400) is not allocated to each terminal / base station.
  • a plurality of continuous time slots are simultaneously assigned to all terminals and base stations on the hop communication path, and these time slots are handled as one large time slot.
  • This time slot allocated collectively is called a block allocation time slot (600).
  • Fig. 6 shows the specific communication protocol.
  • the data signal (601) is transmitted from the base station (100) to the terminal (203) through the terminal (201) and the terminal (202), and the Ack signal (602) from the terminal (203) is transmitted to the base station (100).
  • the Ack (602) here is different from the Mac layer Ack (422) described above, and is an application layer that confirms whether the data signal (601) transmitted by the base station (100) has reached the destination terminal. Ack.
  • this Ack is referred to as an Ack signal (602) and is distinguished from the Mac layer Ack (422).
  • the base station (100) assigns a number of consecutive time slots corresponding to the number of hop stages of multi-hop communication to all terminals (201, 202, 203) and the base station (100) on the route.
  • three slots are allocated to the number of three hop stages from the base station (100) to the terminal (203).
  • Each terminal treats the allocated continuous slot as one large time slot (block allocation time slot (600)), and performs transmission and reception between the block allocation time slots (600) regardless of the division of the time slot (400). Can do.
  • the terminals other than the transmission source (201, 202, 203) start waiting for reception after a predetermined time has elapsed.
  • each terminal enters a standby state in accordance with a signal reception timing expected according to the number of hopping stages.
  • the terminal (201) and terminal (202) corresponding to the relay station for multi-hop communication do not return the Mac layer Ack (422) to the transmission source terminal or base station, and immediately go to the next destination.
  • the data signal (601) is transferred. After that, it waits in the reception waiting state again.
  • the terminal (203) confirms that the received data signal (601) is addressed to itself, and transmits an Ack signal (602) notifying the arrival of the signal to the terminal (202).
  • the base station (100) When the base station (100) receives the Ack signal (602) from the terminal (203), the base station (100) checks which data signal is the Ack signal, and if there is no problem, records that the signal has reached the terminal (203). Complete the communication session.
  • the data signal (601) can be transferred continuously regardless of the width of the time slot (400), so that the transmission delay time in multi-hop communication can be shortened.
  • the Ack signal (422) of the Mac layer is omitted and signal transmission is confirmed by the Ack signal (602) in the entire multi-hop communication, the number of signal transmission and reception is reduced, and the entire transmission delay time can be reduced. it can.
  • the present invention can also be applied to a system in which each terminal and base station performs carrier sense before packet transmission (402) to confirm the status of the communication channel, and performs communication if not used.
  • time slots are assigned to a plurality of terminals at the same time. However, since a plurality of terminals do not transmit data signals at the same time as shown in FIG. 6, no communication collision occurs in the own system. When another system is using the channel, communication is avoided after carrier sense, and signal retransmission processing described later is performed in the same manner as in the case of communication failure.
  • FIG. An example of the operation when communication failure occurs is shown in FIG.
  • a case where communication from the terminal (202) to the terminal (203) has failed in the process of sending the data signal (601) from the base station (100) to the terminal (203) will be described.
  • each terminal on the multi-hop communication path knows in advance from the base station how many relay stations it is.
  • Each relay station After receiving the data signal (601), sets an Ack signal response waiting time (701) according to the number of hops of the relay station and starts counting.
  • This Ack signal response waiting time (701) becomes shorter as the relay station becomes a subsequent relay station, and each relay station is set to always time out earlier than the relay station upstream of itself.
  • each terminal cannot receive the Ack signal (602) by the time-out period after transferring the data signal, it is determined that the signal has not reached the next terminal. In that case, signal unreachable information (603) for notifying the base station (100) of signal unreachability is transmitted to the preceding terminal.
  • the relay station that has received the signal unreachable information (603) transfers it to the base station (100) in the same manner as the normal Ack signal (602).
  • the base station (100) recognizes where the signal is interrupted by the received signal unreachable information (603), and sets a retransmission means.
  • the signal is retransmitted using the retransmission slot (502) in the super frame (500).
  • FIG. 1 An example of the communication protocol at this time is shown in FIG. 1
  • the terminal (202) that needs to be retransmitted performs carrier sense after a random delay time when it reaches the retransmission slot (502), and confirms that the surrounding terminals do not use the retransmission slot.
  • FIG. 17 shows an operation flowchart of the relay station / terminal in FIGS. 6 and 7, and FIG. 18 shows an operation flowchart of the base station. Further, FIG. 19 shows an operation flowchart at the time of signal retransmission of the relay station in FIG.
  • FIG. 9 shows an example of a transmission method of the Ack signal (602) to the base station (100) when the retransmission data signal (604) reaches the destination terminal.
  • the Ack signal (602) is returned to the base station (100) as a block of those superframes. Communicate using the assigned time slot (600).
  • the terminal (203) needs to transmit the Ack signal (602) as shown in FIG. 9, a period (for confirming that data transmission is not performed in the time slot from the head of the block allocation time slot (600) ( The slot unused confirmation period (702)) waits.
  • the terminal 3 determines that this block allocation time slot (600) is not being used, and the Ack signal ( 602) toward the base station (100).
  • the terminal (202) and the terminal (201) each receive the Ack signal (602) and transfer it to the next transfer destination, the Ack signal (602) is transmitted to the base station (100) within the block allocation time slot (600). Can send.
  • FIG. 20 shows an operation flowchart when the Ack signal is retransmitted by the relay station in FIG.
  • the Mac layer Ack (422) for individual communication is not transmitted at the time of packet transmission in FIG. 6, and the Ack signal (602) is returned from the terminal (203) to the base station (100).
  • the time slot allocation method of the present invention can be applied to communication in which the Mac layer Ack (422) for one-to-one communication is transmitted.
  • FIG. 10 shows an example of a communication protocol when sending the Mac layer Ack (422).
  • the case where the data signal (601) is transmitted from the base station (100) to the terminal (203) is shown.
  • a plurality of time slots are combined into one block allocation time slot (600), and communication is performed while ignoring the conventional time slot frame.
  • the data signal (601) is transmitted.
  • the receiving terminal returns a Mac layer Ack (422).
  • the data signal (601) is transferred. Such a transfer is repeated to transmit the data signal (601) to the terminal (203), and the terminal (203) returns an Ack signal (602) to the base station (100).
  • the receiving terminal In response to this Ack signal (602), the receiving terminal returns the Mac layer Ack signal (422) and confirms signal transmission.
  • the Ack signal response waiting time (703) of the Mac layer at this time is set to a time shorter than the Ack signal response waiting time (701) of FIG.
  • FIG. 12 shows an example of a protocol for transmitting the signal unachieved information (603) in the second embodiment to the base station.
  • Each terminal performs a measurement using a timer from the head of the block allocation time slot (600), and receives a data signal (601) from the base station, and sends an Ack signal (602) from the transfer destination terminal as an Ack signal response. If the signal cannot be received within the waiting time (704), signal unreachable information (603) is sent to the base station (100).
  • the terminal (202) after transmitting the data signal (601), the terminal (202) does not return the Mac layer Ack (422) from the terminal (203) within the Mac layer Ack response waiting time (703). It was. Since the timeout of the Ack signal response waiting time (704) occurred during the Mac layer Ack response waiting time (703) for this retransmission, the signal unreachable information (603) is transmitted to the base station (100).
  • FIG. 21 shows a signal transmission flowchart of the relay station / terminal in FIGS. 10 to 12, and FIG. 22 shows a signal transfer flowchart.
  • the Ack signal (602) reply from the data signal (601) destination terminal (200) to the base station (100) is returned to the block allocation time slot of the next superframe (500). (600).
  • the terminal (200) similarly to the retransmission of the data signal (601), the terminal (200) first detects in the retransmission slot (502) whether the other neighboring terminals are not using the retransmission slot (502) or carrier sense after a random delay time. If not used, an Ack signal (602) is transmitted. By repeating this procedure during the retransmission slot (502), the Ack signal (602) is transmitted to the base station (100).
  • the retransmission data signal (604) is transmitted using the retransmission slot (502), and only the Ack signal (602) is returned using the block allocation time slot (600).
  • the data signal (601) may not reach the destination terminal with only the retransmission slots (502) in one superframe.
  • FIG. 13 shows an example of a protocol when signal retransmission is performed using block allocation time slots.
  • a data signal (601) is sent from the base station (100) to the terminal (203) via the terminal (201) and the terminal (202), and communication from the terminal (202) to the terminal (203) in the process is performed.
  • the case of failure will be described. Since the terminal (202) could not receive the Ack signal (602) from the terminal (203), the terminal (202) recognizes the communication failure in the previous block allocation time slot (600) and is in a signal retransmission waiting state.
  • the terminal (202) first waits in a signal waiting state from the beginning of the time slot as usual. If the data signal (601) is not received from the terminal (201) even after the slot unusedness confirmation period (702) has passed from the beginning of the time slot, the terminal (202) transmits data in this block allocation time slot (600). It is determined that there is no signal communication, and a retransmission data signal (604) is sent to the terminal (203).
  • FIG. 23 shows a signal retransmission flowchart of the relay station / terminal in FIG.
  • the Ack signal (602) from the data destination terminal (200) to the base station (100) is sent back to the next block allocation time slot (600) or retransmission slot (502). I went with it.
  • a terminal may communicate as a relay station in communication with a destination other than when the terminal itself becomes a data signal destination.
  • the Ack signal can be transmitted to the base station without causing a new communication.
  • FIG. 24 shows a signal transmission flowchart of the relay station / terminal in FIG.
  • the base station (100) When the base station (100) receives the signal unreachable information (603) after transmitting the data signal (601), the base station (100) stands by in the signal retransmission mode. In this state, when the next block allocation time slot (600) is reached, the data signal (601) is retransmitted. At this time, it is also possible to use a technique for improving communication reliability compared to the previous signal transmission. Specific techniques for improving communication reliability include increasing signal transmission output, adding error correction codes, changing communication channels, and the like.
  • the same signal is sent again from the base station in the next block allocation time slot.
  • the base station (100) When the base station (100) receives the signal unreachable information (603) after transmitting the data signal (601), the base station (100) stands by in the signal retransmission mode. In this state, after the data transmission interval (503) elapses, a data signal having two times of data is sent together with the data signal (601) sent before the next data transmission.
  • the relay station transmits the data signal to the destination terminal in the same way as a normal data signal.
  • the destination terminal checks the contents of the packet, confirms that data for two times is included, and returns an Ack signal (602) indicating that data for two times has been received to the base station (100).
  • the base station (100) When receiving the Ack signal (602), the base station (100) records that data transmission for two times is completed, and ends the communication.
  • the purpose of this embodiment is to prevent repeated communication interruption by changing a multi-hop route and retransmitting a signal when communication interruption occurs.
  • each terminal is notified of the release of the block allocation time slot (600) allocated to the route of the terminal (201, 202, 204).
  • This notification is sent to all terminals on the route by means such as a control channel that is unlikely to cause communication failure.
  • notification is performed using the method with high communication reliability described in the sixth embodiment.
  • a new time slot block is allocated to the terminal on the new route.
  • FIG. 25 is a flowchart of the base station route resetting operation in FIG.
  • the base station (100) receives the signal unreachable information (603) from the terminal (202) and waits in the signal retransmission mode. In this state, it waits for the next opportunity to perform communication including the destination terminal (204) on the route.
  • the base station (100) receives the data addressed to the terminal (205). And a composite data signal (607) in which the data addressed to the terminal (204) is combined and sent to the terminal (205).
  • the terminal (204) When the terminal (204) receives the composite data signal (607), it confirms the contents, receives the data addressed to itself, and transfers the signal to the terminal 205. At this time, the data portion addressed to itself may be deleted and the data signal (601) may be reconfigured and sent to the terminal (205).
  • the terminal (205) confirms the content of the signal, receives data addressed to itself, and sends an Ack signal (602) corresponding thereto to the terminal (204).
  • the terminal (204) sends a composite Ack signal (606) in which its Ack is added to the Ack signal (602) to the base station (100) via the terminals (203, 201).
  • the base station confirms the contents of the composite Ack signal (606), confirms and records that the data has arrived at each of the terminals (205, 204), and completes the communication.
  • the terminal (204) If the Ack signal (602) from the terminal (205) does not reach the terminal (204), the terminal (204) times out after the Ack signal response waiting time (701), and sends its own Ack signal (602). Create and send to base station (100).
  • the base station (100) When the base station (100) receives the Ack signal (602), it records the completion of communication addressed to the terminal (204) and stands by in the retransmission mode addressed to the terminal (205).
  • FIG. 26 shows an operation flowchart of the base station in FIG.

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Abstract

In the conventional TDMA wireless communication system, when a multi-hop communication is performed, time slots the number of which is equal to or greater than the number of multi-hop stages are required, so that the transmission delay time occurring in the communication from a transmission source to a destination is long. When a multi-hop communication is performed, all of the terminals and base station on a communication path are grouped into a single group, and a plurality of consecutive time slots are allocated to the group. Those time slots are regarded as a single large block time slot, in which the terminals and base station repetitively perform quickly transferring a signal, which was transmitted from a terminal of the preceding multi-hop stage, to a terminal of the next multi-hop stage, whereby the transmission delay time of multi-hop communication can be shortened.

Description

無線通信システム、無線通信基地局および無線通信端末Wireless communication system, wireless communication base station, and wireless communication terminal
　本発明は無線通信システム、無線通信基地局および無線通信端末に関し、特に複数の端末を無線中継局として経由して通信を行う無線通信システム（機器）に関する。 The present invention relates to a wireless communication system, a wireless communication base station, and a wireless communication terminal, and more particularly to a wireless communication system (device) that performs communication via a plurality of terminals as wireless relay stations.
　無線ＬＡＮや携帯電話などの個人向け無線通信システムの普及に続き、産業分野での無線通信に対する需要が高まっている。例えばプラントなどの製造業の現場では多くの機器が有線で制御されているため、新たな機器を設置する場合においてはその機器に制御情報を伝達するためのケーブルの設置工事が必須となる。 Demand for wireless communication in the industrial field is increasing following the spread of personal wireless communication systems such as wireless LAN and mobile phones. For example, since many devices are controlled by wire in the manufacturing industry such as a plant, when installing a new device, installation work of a cable for transmitting control information to the device is indispensable.
　このため設置機器本体のコストに加え、ケーブルの敷設工事のコスト、さらに工事期間中に製造ラインを止めなければならないことによる損失が発生する。 For this reason, in addition to the cost of the installed equipment itself, there will be losses due to the cost of cable laying construction and the fact that the production line must be stopped during the construction period.
　これに対し、これらの制御情報を無線で送ることができればコストを大幅に軽減することができる。そのような制御情報は指示のタイミングが遅れると機械の誤作動や暴走を引き起こすため、短い遅延時間で誤りなく伝送されることが要求されている。従来の無線通信方式で短遅延通信に適しているのは、システム全体で時間同期してタイムスロットという短い時間単位を共有し、タイムスロットごとに通信する端末を指定するＴＤＭＡ（Ｔｉｍｅ　Ｄｉｖｉｓｉｏｎ　Ｍｕｌｔｉｐｌｅ　アクセス）方式であった。 In contrast, if the control information can be transmitted wirelessly, the cost can be greatly reduced. Such control information is required to be transmitted without error in a short delay time, because if the instruction timing is delayed, the machine may malfunction or run away. The conventional wireless communication method is suitable for short-delay communication. The TDMA (Time Division Multiple Access) is used to share a short time unit called a time slot in synchronization with the entire system, and to specify a terminal to communicate for each time slot. It was a method.
　一方で障害物の多い工場等の環境では遮蔽により信号が届かない場所が多く発生する。このような場所で確実に通信を行うためには、特許文献１、２に開示のように中継局を経由して信号を伝達するマルチホップ通信が知られている。また特許文献３に開示のようにマルチホップ通信において複数の端末が同時に信号を送信することで通信の瞬断を防ぐ方法も知られている。 On the other hand, there are many places where signals do not reach due to shielding in environments with many obstacles. In order to reliably perform communication in such a place, multi-hop communication that transmits a signal via a relay station as disclosed in Patent Documents 1 and 2 is known. Further, as disclosed in Patent Document 3, there is also known a method for preventing instantaneous interruption of communication by simultaneously transmitting signals from a plurality of terminals in multi-hop communication.
特開平０８－０９７８２１号公報Japanese Patent Laid-Open No. 08-097821 特開２００１－１８９９７１号公報JP 2001-189971 A 特開２００８－１３１２０９号公報JP 2008-131209 A
　従来のＴＤＭＡ無線通信では、マルチホップ通信を行う際には1つのホップに対して１つのタイムスロットを割り当てる必要があったため、送信元から宛先までの通信に対しタイムスロット幅とホップ段数に比例した遅延が生じた。 In conventional TDMA wireless communication, when performing multi-hop communication, it was necessary to assign one time slot to one hop, so the communication from the source to the destination was proportional to the time slot width and the number of hop stages. There was a delay.
　このような遅延を削減するためにはタイムスロット幅を短くする必要があった。 In order to reduce such a delay, it was necessary to shorten the time slot width.
　しかし、タイムスロット幅が短いと通信システムは高い時間同期精度を要求されるため、同期維持用の通信回数増加に伴う消費電力の増大や通信帯域の占有が問題となった。あるいはシステム内の各端末にそれぞれ同期誤差の小さい高精度なクロックを付与する必要があるため、端末コストが増大するという問題があった。 However, since the communication system is required to have high time synchronization accuracy when the time slot width is short, the increase in power consumption accompanying the increase in the number of communication for maintaining synchronization and the occupation of the communication band become problems. Alternatively, a high-accuracy clock with a small synchronization error needs to be given to each terminal in the system, which causes a problem that the terminal cost increases.
　本発明では、端末・基地局間での通信で複数の中継局を経由するアドホック通信に対し、タイムスロットの割り当てを管理する基地局が、アドホック通信の経路上にある基地局と全ての端末に対し、複数の連続したタイムスロットをまとめて1つの大きなタイムスロットとして割り当て、その中で従来のタイムスロットの枠組みは無視して信号を受信したら即座（即ち、「直ちに」）に次の転送先に信号を転送することを繰り返す。 In the present invention, for ad hoc communication via a plurality of relay stations in communication between a terminal and a base station, a base station that manages time slot allocation is provided to a base station and all terminals on the ad hoc communication path. In contrast, multiple consecutive time slots are allocated together as one large time slot, in which the conventional time slot framework is ignored and a signal is received immediately (ie, “immediately”) to the next destination. Repeat the signal transfer.
　これにより、送信元から宛先まで迅速に信号を伝送することができる。 This makes it possible to quickly transmit signals from the source to the destination.
　本発明により、ＴＤＭＡアドホックネットワークにおいて、タイムスロットの幅を変更することなく、送信元から宛先までの通信で生じる伝送遅延を削減することができる。また本発明はアドホック通信以外の通信に影響を及ぼさないので、従来のＴＤＭＡ通信システムの枠組み内でアドホック通信の伝送遅延を削減することができる。 According to the present invention, in a TDMA ad hoc network, it is possible to reduce transmission delay caused by communication from a transmission source to a destination without changing the width of a time slot. Further, since the present invention does not affect communications other than ad hoc communication, transmission delay of ad hoc communication can be reduced within the framework of a conventional TDMA communication system.
本発明のシステム構成の例である。It is an example of the system configuration | structure of this invention. 本発明の基地局の構成例である。It is a structural example of the base station of this invention. 本発明の端末の構成例である。It is an example of a structure of the terminal of this invention. 本発明のタイムスロット構成例である。It is a time slot configuration example of the present invention. 本発明のスーパーフレームの構成例である。It is a structural example of the super frame of this invention. 本発明の第1の実施例の通信プロトコルの例である。2 is an example of a communication protocol according to the first embodiment of this invention. 本発明の第1の実施例の信号未達時の通信プロトコルの例である。3 is an example of a communication protocol when a signal is not reached in the first embodiment of the present invention. 本発明の第1の実施例の再送信号伝達プロトコルの例である。2 is an example of a retransmission signaling protocol according to the first embodiment of the present invention. 本発明の第1の実施例の再送発生時のＡｃｋ信号伝達プロトコルの例である。It is an example of the Ack signal transmission protocol at the time of retransmission occurrence in the first embodiment of the present invention. 本発明の第２の実施例の通信プロトコルの例である。It is an example of the communication protocol of 2nd Example of this invention. 本発明の第２の実施例の通信失敗時の通信プロトコルの例である。It is an example of the communication protocol at the time of communication failure of 2nd Example of this invention. 本発明の第２の実施例の信号未達時の通信プロトコルの例である。It is an example of the communication protocol at the time of the signal unreachable of 2nd Example of this invention. 本発明の第４の実施例の信号再送時の通信プロトコルの例である。It is an example of the communication protocol at the time of signal retransmission of the 4th Example of this invention. 本発明の第５の実施例の信号伝達方法の例である。It is an example of the signal transmission method of the 5th Example of this invention. 本発明の第８の実施例の信号伝達方法の例である。It is an example of the signal transmission method of the 8th Example of this invention. 本発明の第９の実施例の信号伝達方法の例である。It is an example of the signal transmission method of 9th Example of this invention. 本発明の第１の実施例の中継局・端末の動作フローチャートの例である。It is an example of the operation | movement flowchart of the relay station and terminal of 1st Example of this invention. 本発明の第１の実施例の基地局の動作フローチャートの例である。It is an example of the operation | movement flowchart of the base station of 1st Example of this invention. 本発明の第１の実施例の中継局・端末の信号再送時動作フローチャートの例である。It is an example of the operation | movement flowchart at the time of the signal retransmission of the relay station and terminal of 1st Example of this invention. 本発明の第１の実施例の中継局・端末のＡｃｋ信号再送時動作フローチャートの例である。It is an example of the operation | movement flowchart at the time of Ack signal resending of the relay station and terminal of 1st Example of this invention. 本発明の第２の実施例の中継局・端末の信号送信フローチャートの例である。It is an example of the signal transmission flowchart of the relay station and terminal of 2nd Example of this invention. 本発明の第２の実施例の中継局・端末の信号転送フローチャートの例である。It is an example of the signal transfer flowchart of the relay station and terminal of 2nd Example of this invention. 本発明の第４の実施例の中継局・端末の信号再送フローチャートの例である。It is an example of the signal resending flowchart of the relay station and terminal of 4th Example of this invention. 本発明の第５の実施例の中継局・端末の信号送信フローチャートの例である。It is an example of the signal transmission flowchart of the relay station and terminal of 5th Example of this invention. 本発明の第８の実施例の基地局ルート再設定フローチャートの例である。It is an example of the base station route reset flowchart of the 8th Example of this invention. 本発明の第９の実施例の基地局の動作フローチャートの例である。It is an example of the operation | movement flowchart of the base station of the 9th Example of this invention.
　以下、本発明の実施形態について図面を用いながら説明する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
　なお、以下の説明で述べる通信方式とは、例えば、無線ＬＡＮのＩＥＥＥ８０２．１１a方式やＩＥＥＥ８０２．１１ｂ方式、Ｚｉｇｂｅｅ（なお、” Ｚｉｇｂｅｅ”は、ZigBee Alliance, Inc.の登録商標である。）やＵＷＢ（Ｕｌｔｒａ　Ｗｉｄｅｂａｎｄ）方式、ＩＳＡ１００．１１ａ方式を示す。 Note that the communication methods described in the following description are, for example, IEEE802.11a method, IEEE802.11b method of wireless LAN, Zigbee (“Zigbee” is a registered trademark of ZigBee Alliance, Inc.) and UWB. (Ultra Wideband) method and ISA100.11a method are shown.
　また、以下の説明では、基地局から端末への制御情報の送受信を想定しているが、基地局のリクエストを受けて端末が測定したデータを基地局に送るデータ通信にも適用できる。さらにまた、端末から端末への通信に関しても適用可能である。 In the following description, transmission / reception of control information from the base station to the terminal is assumed, but the present invention can also be applied to data communication in which data measured by the terminal in response to a request from the base station is transmitted to the base station. Furthermore, the present invention can also be applied to communication from terminal to terminal.
　図1は本実施例のシステム構成を示している。本実施例ではタイムスロットの管理を行い、また端末への制御情報伝達を行う基地局（１００）と、センサや工作機械と接続して基地局（１００）との間でデータの送受信を行う複数の端末(２０１から２０６)から構成される。 Fig. 1 shows the system configuration of this embodiment. In this embodiment, time slots are managed and a base station (100) that transmits control information to a terminal and a plurality of base stations (100) that are connected to sensors and machine tools to transmit and receive data. Terminal (201 to 206).
　また基地局は広域網などのネットワーク（３００）に接続できる。本実施例では、マルチホップ通信が可能であればネットワーク構成には依存しない。以後の説明では一例としては基地局から端末へ向けて通信を行い、端末が基地局へ応答を返すクラスタツリー型構成の場合について説明する。 Also, the base station can be connected to a network (300) such as a wide area network. In this embodiment, as long as multi-hop communication is possible, it does not depend on the network configuration. In the following description, as an example, a case of a cluster tree configuration in which communication is performed from the base station to the terminal and the terminal returns a response to the base station will be described.
　本システムで使用される通信方式はＴＤＭＡとする。ＴＤＭＡのタイムスロットは基地局が管理し、割り当てる。 The communication method used in this system is TDMA. The TDMA time slot is managed and allocated by the base station.
　基地局（１００）の構成を図２に示す。基地局はシステム内のタイムスロットを管理するタイムスロット管理機能部（１０１）、およびシステム内のネットワーク構成に関する情報を記録したネットワーク構成データベース部（ＤＢ）（１０２）を持つ。またシステム内の時刻同期を制御するシステム同期機能部（１０３）、端末とのデータ送受信を管理するデータ通信機能部(または「データ送受信機能部」)（１０４）を持つ。それらの機能から要求される信号送受信は無線通信機能部（１０５）を通じて無線信号となりアンテナ（１０６）から送受信される。また基地局は広域通信インタフェース（ＩＦ）（１０７）を持ち、広域網（３００）と接続して情報の送受信を行うことができる。 The configuration of the base station (100) is shown in FIG. The base station has a time slot management function unit (101) that manages time slots in the system, and a network configuration database unit (DB) (102) that records information related to the network configuration in the system. In addition, a system synchronization function unit (103) for controlling time synchronization in the system and a data communication function unit (or “data transmission / reception function unit”) (104) for managing data transmission / reception with the terminal are provided. Signal transmission / reception required from these functions becomes a radio signal through the radio communication function unit (105) and is transmitted / received from the antenna (106). The base station has a wide area communication interface (IF) (107), and can connect to the wide area network (300) to transmit and receive information.
　本システムの端末（２００）の構成図を図３に示す。 The configuration diagram of the terminal (200) of this system is shown in FIG.
　端末はシステム時刻との同期を維持する同期維持機能部（２１１）と基地局から通知されるシステム構成に関する情報を記憶するシステム情報メモリ（２１２）を持つ。 The terminal has a synchronization maintaining function unit (211) that maintains synchronization with the system time and a system information memory (212) that stores information on the system configuration notified from the base station.
　また基地局や他の端末とのデータ送受信を行うデータ送受信機能部（２１３）を持つ。それらの機能から要求される信号送受信は無線通信機能部（２１４）を通じて無線信号となりアンテナ（２１５）から送受信される。また端末はセンサや工作機械のような外部機器（２１７）と外部インタフェース部（ＩＦ）（２１６）を通じて接続し、制御情報を送ったり、そこから得られる情報を基地局や他の端末に送ったりすることができる。これらの外部機器と端末は一体化されていても良い。 Also, it has a data transmission / reception function unit (213) for transmitting / receiving data to / from the base station and other terminals. Signal transmission / reception required from these functions becomes a radio signal through the radio communication function unit (214) and is transmitted / received from the antenna (215). The terminal is connected to an external device (217) such as a sensor or a machine tool through an external interface unit (IF) (216) to send control information and send information obtained therefrom to a base station or another terminal. can do. These external devices and terminals may be integrated.
　本システムで使用されるＴＤＭＡで使用される、通常のタイムスロット（４００）の構成を図４に示す。 FIG. 4 shows the structure of a normal time slot (400) used in TDMA used in this system.
　送信側はタイムスロット先頭から送信オフセット（４０１）経過後にパケット送信（４０２）を行う。この送信オフセット（４０１）は送信側と受信側のシステム時刻の同期誤差を吸収するためのものである。送信側はパケット（４２１）送信後に受信準備（４０３）を開始し、その後受信側からのＡｃｋを待ち受ける（４０４）。 The transmission side performs packet transmission (402) after transmission offset (401) has elapsed from the beginning of the time slot. This transmission offset (401) is for absorbing a synchronization error between the system times of the transmission side and the reception side. The transmission side starts reception preparation (403) after transmitting the packet (421), and then waits for Ack from the reception side (404).
　ここで送受信されるＡｃｋ信号（４２２）はＭａｃ層での信号受信を確認するものであるため、以後はＭａｃ層Ａｃｋと呼ぶ。 Since the Ack signal (422) transmitted / received here confirms signal reception in the Mac layer, it will be referred to as the Mac layer Ack hereinafter.
　送信側がＭａｃ層Ａｃｋ（４２２）を受信（４０５）できれば、その通信は完了する。Ｍａｃ層Ａｃｋ（４２２）を受信できなかった場合は通信が失敗したと判断される。 If the transmission side can receive (405) the Mac layer Ack (422), the communication is completed. If the Mac layer Ack (422) cannot be received, it is determined that communication has failed.
　受信側は送信オフセット（４０１）に対応した待ち時間である受信オフセット（４１１）の後、パケット受信待ち受け（４１２）を開始する。送信側からのパケット（４２１）を受信（４１３）の後、そのパケット内容を確認し問題がなければＭａｃ層Ａｃｋ（４２２）を準備する（４１４）。その後、端末に向けてＭａｃ層Ａｃｋ（４２２）を送信する（４１５）。 The reception side starts a packet reception standby (412) after a reception offset (411) which is a waiting time corresponding to the transmission offset (401). After receiving the packet (421) from the transmission side (413), the packet content is confirmed, and if there is no problem, the Mac layer Ack (422) is prepared (414). Thereafter, the Mac layer Ack (422) is transmitted to the terminal (415).
　本システムで使用されるＴＤＭＡ方式のスーパーフレーム（５００）の構成例を図５に示す。なお、スーパーフレームとは端末（２００）・基地局（１００）へのタイムスロット（４００）（図４参照。）割り当ての繰り返し周期であり、複数のタイムスロットで構成される。スーパーフレーム（５００）は通常の通信に使用される通常スロット（５０１）と、通常スロットで通信が失敗だった場合に信号再送を行う再送スロット（５０２）で構成される。 FIG. 5 shows a configuration example of a TDMA superframe (500) used in this system. The superframe is a repetition cycle of assigning the time slot (400) (see FIG. 4) to the terminal (200) / base station (100), and is composed of a plurality of time slots. The super frame (500) includes a normal slot (501) used for normal communication and a retransmission slot (502) that performs signal retransmission when communication fails in the normal slot.
　通常スロットは端末及び基地局の間で行われるデータ通信と同期維持用の信号伝達の双方に使用される。本実施例では、基地局はデータ送信間隔（５０３）ごとに各端末に対してデータ送信を行う。このデータ送信間隔はスーパーフレームの一定数倍になっている。 The normal slot is used for both data communication between the terminal and the base station and signal transmission for maintaining synchronization. In this embodiment, the base station transmits data to each terminal at every data transmission interval (503). This data transmission interval is a constant multiple of the superframe.
　タイムスロット（４００）は基地局（１００）によって管理され、それぞれのタイムスロットについて通信する端末（２００）や基地局（１００）、及び使用する通信チャネルが事前に指定されている。通常の通信に対しては1つのタイムスロット（４００）に送信側と受信側のそれぞれの端末、もしくは基地局を１つずつ割り当てる。タイムスロット指定に関する情報は基地局（１００）から該当する端末（２００）に送られる。また端末（２００）が移動しない場合はオペレータにより事前に各端末や基地局に直接、タイムスロット指定に関する情報を設定してもよい。 The time slot (400) is managed by the base station (100), and the terminal (200) and the base station (100) that communicate with each time slot and the communication channel to be used are designated in advance. For normal communication, one terminal or base station on the transmitting side and one on the receiving side is allocated to one time slot (400). Information about time slot designation is sent from the base station (100) to the corresponding terminal (200). If the terminal (200) does not move, the operator may set information related to time slot designation directly in advance to each terminal or base station.
　本発明では、送信元と宛先の間に1つ以上の端末（２００）が中継局として存在するマルチホップ通信の場合、それぞれの端末・基地局にタイムスロット（４００）を割り当てるのではなく、マルチホップ通信の経路上にある全ての端末・基地局に連続する複数のタイムスロットを同時に割り当て、それらのタイムスロットを1つの大きなタイムスロットとして取り扱う。このまとめて割り当てられたタイムスロットをブロック割り当てタイムスロット（６００）と呼ぶ。 In the present invention, in the case of multi-hop communication in which one or more terminals (200) exist as relay stations between a transmission source and a destination, a time slot (400) is not allocated to each terminal / base station. A plurality of continuous time slots are simultaneously assigned to all terminals and base stations on the hop communication path, and these time slots are handled as one large time slot. This time slot allocated collectively is called a block allocation time slot (600).
　具体的な通信プロトコルを図６にしめす。ここでは基地局（１００）から端末（２０１）、端末（２０２）を通じて端末（２０３）にデータ信号（６０１）を送信し、端末（２０３）からのＡｃｋ信号（６０２）を基地局（１００）に返信する場合について説明する。なお、ここでのＡｃｋ（６０２）は前述のＭａｃ層Ａｃｋ（４２２）とは違い、基地局（１００）が送信したデータ信号（６０１）が宛先の端末にまで到達したかを確認するアプリケーション層のＡｃｋである。以後、このＡｃｋをＡｃｋ信号（６０２）と呼び、Ｍａｃ層Ａｃｋ（４２２）と区別する。 Fig. 6 shows the specific communication protocol. Here, the data signal (601) is transmitted from the base station (100) to the terminal (203) through the terminal (201) and the terminal (202), and the Ack signal (602) from the terminal (203) is transmitted to the base station (100). The case of replying will be described. The Ack (602) here is different from the Mac layer Ack (422) described above, and is an application layer that confirms whether the data signal (601) transmitted by the base station (100) has reached the destination terminal. Ack. Hereinafter, this Ack is referred to as an Ack signal (602) and is distinguished from the Mac layer Ack (422).
　基地局（１００）はマルチホップ通信のホップ段数に対応した数の連続したタイムスロットを経路上の全ての端末（２０１，２０２，２０３）や基地局（１００）に割り当てる。図６の例では基地局（１００）から端末（２０３）までの３段のホップ段数に対して３スロットを割り当てている。各端末は割り当てられた連続スロットを1つの大きなタイムスロット（ブロック割り当てタイムスロット（６００））として扱い、ブロック割り当てタイムスロット（６００）の間はタイムスロット（４００）の区切りに関係なく送受信を行うことができる。このとき、送信元以外の端末（２０１，２０２，２０３）はそれぞれ一定時間経過後に受信待ち受けを開始する。 The base station (100) assigns a number of consecutive time slots corresponding to the number of hop stages of multi-hop communication to all terminals (201, 202, 203) and the base station (100) on the route. In the example of FIG. 6, three slots are allocated to the number of three hop stages from the base station (100) to the terminal (203). Each terminal treats the allocated continuous slot as one large time slot (block allocation time slot (600)), and performs transmission and reception between the block allocation time slots (600) regardless of the division of the time slot (400). Can do. At this time, the terminals other than the transmission source (201, 202, 203) start waiting for reception after a predetermined time has elapsed.
　例えば図６では、全端末が通常の通信と同じようにタイムスロット先頭から受信オフセット時間（４１１）経過後に受信待ち受け状態に入っている。この受信オフセット時間を０に設定し、全端末がブロック割り当てタイムスロットの先頭から待ち受けを開始しても問題ない。あるいは各端末がホッピング段数に応じて予想される信号受信タイミングに合わせて受信待ち受けに入るのも本発明の範疇である。 For example, in FIG. 6, all terminals are in a reception standby state after the reception offset time (411) has elapsed from the beginning of the time slot, as in normal communication. There is no problem even if this reception offset time is set to 0 and all terminals start waiting from the beginning of the block allocation time slot. Alternatively, it is also within the scope of the present invention that each terminal enters a standby state in accordance with a signal reception timing expected according to the number of hopping stages.
　マルチホップ通信の中継局に当たる端末（２０１）、端末（２０２）はデータ信号（６０１）を受信すると送信元の端末や基地局にＭａｃ層Ａｃｋ（４２２）を返さず、すぐに次の宛先に向かってデータ信号（６０１）を転送する。その後また受信待ち状態で待機する。端末（２０３）は受け取ったデータ信号（６０１）が自身宛であることを確認し、信号到達を知らせるＡｃｋ信号（６０２）を端末（２０２）に送信する。中継局である端末（２０１）、端末（２０２）は端末（２０３）からのＡｃｋ信号（６０２）を次の宛先に転送する。 Upon receiving the data signal (601), the terminal (201) and terminal (202) corresponding to the relay station for multi-hop communication do not return the Mac layer Ack (422) to the transmission source terminal or base station, and immediately go to the next destination. The data signal (601) is transferred. After that, it waits in the reception waiting state again. The terminal (203) confirms that the received data signal (601) is addressed to itself, and transmits an Ack signal (602) notifying the arrival of the signal to the terminal (202). The terminals (201) and (202), which are relay stations, transfer the Ack signal (602) from the terminal (203) to the next destination.
　基地局（１００）は端末（２０３）からのＡｃｋ信号（６０２）を受信したら、それがどのデータ信号に対するＡｃｋ信号かを確認し、問題がなければ端末（２０３）まで信号到達したことを記録し、通信セッションを完了する。このプロトコルを用いることにより、タイムスロット（４００）の幅に関係なく連続してデータ信号（６０１）を転送することができるため、マルチホップ通信時の伝送遅延時間を短縮することができる。またこのときＭａｃ層のＡｃｋ信号（４２２）を省略しマルチホップ通信全体で信号の伝達をＡｃｋ信号（６０２）で確認するため、信号の送受信回数が減少し全体の伝送遅延時間を削減することができる。 When the base station (100) receives the Ack signal (602) from the terminal (203), the base station (100) checks which data signal is the Ack signal, and if there is no problem, records that the signal has reached the terminal (203). Complete the communication session. By using this protocol, the data signal (601) can be transferred continuously regardless of the width of the time slot (400), so that the transmission delay time in multi-hop communication can be shortened. At this time, since the Ack signal (422) of the Mac layer is omitted and signal transmission is confirmed by the Ack signal (602) in the entire multi-hop communication, the number of signal transmission and reception is reduced, and the entire transmission delay time can be reduced. it can.
　なお、各端末及び基地局がパケット送信（４０２）の前にキャリアセンスを行って通信チャネルの状況を確認し、使用されていなければ通信を行う方式にも本発明を適用することができる。本発明では、複数端末に同時にタイムスロットが割り当てられているが、図６に示すようにデータ信号を複数の端末が同時に送信することはないため、自システム内での通信衝突は発生しない。他のシステムがチャネルを使用していた場合は、キャリアセンス後に通信を回避し、通信失敗の場合と同様に後述する信号再送処理を行う。 Note that the present invention can also be applied to a system in which each terminal and base station performs carrier sense before packet transmission (402) to confirm the status of the communication channel, and performs communication if not used. In the present invention, time slots are assigned to a plurality of terminals at the same time. However, since a plurality of terminals do not transmit data signals at the same time as shown in FIG. 6, no communication collision occurs in the own system. When another system is using the channel, communication is avoided after carrier sense, and signal retransmission processing described later is performed in the same manner as in the case of communication failure.
　通信失敗発生時の動作の一例を図７に示す。ここでは先ほどと同様に基地局（１００）から端末（２０３）までデータ信号（６０１）を送る過程において、端末（２０２）から端末（２０３）への通信が失敗した場合について説明する。本システムでは、マルチホップ通信経路上の端末は自身がそれぞれ何段目の中継局であるかをあらかじめ基地局から情報により把握している。 An example of the operation when communication failure occurs is shown in FIG. Here, a case where communication from the terminal (202) to the terminal (203) has failed in the process of sending the data signal (601) from the base station (100) to the terminal (203) will be described. In this system, each terminal on the multi-hop communication path knows in advance from the base station how many relay stations it is.
　各中継局はデータ信号（６０１）受信後に、自身のホップ段数に応じたＡｃｋ信号応答待ち時間（７０１）を設定し、カウントを始める。このＡｃｋ信号応答待ち時間（７０１）は後段の中継局になるほど短くなり、それぞれの中継局は必ず自身より前段の中継局よりも早くタイムアウトを起こすように設定されている。 Each relay station, after receiving the data signal (601), sets an Ack signal response waiting time (701) according to the number of hops of the relay station and starts counting. This Ack signal response waiting time (701) becomes shorter as the relay station becomes a subsequent relay station, and each relay station is set to always time out earlier than the relay station upstream of itself.
　各端末はデータ信号転送後、タイムアウト時間までにＡｃｋ信号（６０２）を受信できなければ、信号が次の端末まで届かなかったと判断する。その場合、信号未達を基地局（１００）に知らせる信号未達情報（６０３）を前段の端末に対して送信する。信号未達情報（６０３）を受けとった中継局は通常のＡｃｋ信号（６０２）と同様にこれを基地局（１００）まで転送する。基地局（１００）は受け取った信号未達情報（６０３）によりどこで信号が途絶したのかを認識し、再送手段を設定する。 If each terminal cannot receive the Ack signal (602) by the time-out period after transferring the data signal, it is determined that the signal has not reached the next terminal. In that case, signal unreachable information (603) for notifying the base station (100) of signal unreachability is transmitted to the preceding terminal. The relay station that has received the signal unreachable information (603) transfers it to the base station (100) in the same manner as the normal Ack signal (602). The base station (100) recognizes where the signal is interrupted by the received signal unreachable information (603), and sets a retransmission means.
　データ信号（６０１）伝送において通信失敗が発生した場合は、スーパーフレーム（５００）内の再送スロット（５０２）を用いて信号の再送を行う。 When a communication failure occurs in the data signal (601) transmission, the signal is retransmitted using the retransmission slot (502) in the super frame (500).
　このときの通信プロトコルの例を図８に示す。 An example of the communication protocol at this time is shown in FIG.
　これは図7のように端末（２０２）から端末（２０３）への通信においてエラーが発生してデータ信号（６０１）が届かなかった場合の再送を示している。通信失敗を起こして再送が必要な端末（２０２）以外は、再送スロット（５０２）では待ち受け状態で待機する。再送が必要な端末（２０２）は再送スロット（５０２）になるとランダムな遅延時間後にキャリアセンスを行い、周囲の端末が再送スロットを使用していないことを確認する。 This indicates retransmission when an error occurs in communication from the terminal (202) to the terminal (203) and the data signal (601) does not arrive as shown in FIG. Except for the terminal (202) that needs to be retransmitted due to a communication failure, it stands by in a standby state in the retransmission slot (502). The terminal (202) that needs to be retransmitted performs carrier sense after a random delay time when it reaches the retransmission slot (502), and confirms that the surrounding terminals do not use the retransmission slot.
　再送スロット（５０２）が使用されていなければ、前回送信できなかった内容を含む再送データ信号（６０４）を送信する。再送スロット（５０２）が既に他の端末に使用されていた場合は次の再送スロットで再送を試みる。図６、図７における中継局・端末の動作フローチャートを図１７に、基地局の動作フローチャートを図１８に示す。また、図８における中継局の信号再送時の動作フローチャートを図１９に示す。 If the retransmission slot (502) is not used, the retransmission data signal (604) including the contents that could not be transmitted last time is transmitted. If the retransmission slot (502) has already been used by another terminal, retransmission is attempted in the next retransmission slot. FIG. 17 shows an operation flowchart of the relay station / terminal in FIGS. 6 and 7, and FIG. 18 shows an operation flowchart of the base station. Further, FIG. 19 shows an operation flowchart at the time of signal retransmission of the relay station in FIG.
　再送データ信号（６０４）が宛先の端末まで到達した場合の、基地局（１００）へのＡｃｋ信号（６０２）の伝達方法の例を図９に示す。データ送信間隔（５０３）がスーパーフレーム（５００）より長い場合、一部のスーパーフレームではデータ送信が行われないため、基地局（１００）へのＡｃｋ信号（６０２）返信はそれらのスーパーフレームのブロック割り当てタイムスロット（６００）を使用して伝達する。図9のように端末（２０３）がＡｃｋ信号（６０２）送信の必要がある場合、ブロック割り当てタイムスロット（６００）の先頭からそのタイムスロットでデータ送信が行われないことを確認するための期間（スロット未使用確認期間（７０２））待機する。 FIG. 9 shows an example of a transmission method of the Ack signal (602) to the base station (100) when the retransmission data signal (604) reaches the destination terminal. When the data transmission interval (503) is longer than the superframe (500), data transmission is not performed in some superframes, so the Ack signal (602) is returned to the base station (100) as a block of those superframes. Communicate using the assigned time slot (600). When the terminal (203) needs to transmit the Ack signal (602) as shown in FIG. 9, a period (for confirming that data transmission is not performed in the time slot from the head of the block allocation time slot (600) ( The slot unused confirmation period (702)) waits.
　この待機期間が過ぎてもデータ信号（６０１）が送られてこなかった場合、端末３はこのブロック割り当てタイムスロット（６００）は使用されていないと判断し、再送データ信号（６０４）に対するＡｃｋ信号（６０２）を基地局（１００）に向けて送信する。 If the data signal (601) has not been sent even after the waiting period has elapsed, the terminal 3 determines that this block allocation time slot (600) is not being used, and the Ack signal ( 602) toward the base station (100).
　端末（２０２）、端末（２０１）はそれぞれＡｃｋ信号（６０２）を受信して次の転送先へ転送するため、ブロック割り当てタイムスロット（６００）内で基地局（１００）までＡｃｋ信号（６０２）を送ることができる。 Since the terminal (202) and the terminal (201) each receive the Ack signal (602) and transfer it to the next transfer destination, the Ack signal (602) is transmitted to the base station (100) within the block allocation time slot (600). Can send.
　スロット未使用確認期間（７０２）中に端末（２０３）が別のデータ信号（６０１）を受信した場合、前の信号と今回受信した信号２つの信号の分を合わせたＡｃｋ信号を作成し、基地局（１００）まで送る。基地局（１００）は受信したＡｃｋ信号（６０２）がどの通信に対するものなのかを確認し、問題なければ通信を終了する。図９における中継局のＡｃｋ信号再送時の動作フローチャートを図２０に示す。 When the terminal (203) receives another data signal (601) during the slot unused confirmation period (702), it creates an Ack signal that combines the previous signal and the two signals received this time, Send to station (100). The base station (100) confirms which communication the received Ack signal (602) is for, and if there is no problem, terminates the communication. FIG. 20 shows an operation flowchart when the Ack signal is retransmitted by the relay station in FIG.
　上述の実施形態では図６のパケット伝送時に、個別の通信に対するＭａｃ層Ａｃｋ（４２２）を送信せず、Ａｃｋ信号（６０２）を端末（２０３）から基地局（１００）まで返していた。これに対し、1対1通信のＭａｃ層Ａｃｋ（４２２）を送る通信においても本発明のタイムスロット割り当て方法は適用可能である。 In the above-described embodiment, the Mac layer Ack (422) for individual communication is not transmitted at the time of packet transmission in FIG. 6, and the Ack signal (602) is returned from the terminal (203) to the base station (100). On the other hand, the time slot allocation method of the present invention can be applied to communication in which the Mac layer Ack (422) for one-to-one communication is transmitted.
　Ｍａｃ層Ａｃｋ（４２２）を送る場合の通信プロトコルの例を図１０に示す。 FIG. 10 shows an example of a communication protocol when sending the Mac layer Ack (422).
　ここでは基地局（１００）から端末（２０３）までデータ信号（６０１）を送信する場合を示している。複数のタイムスロットを合わせて1つのブロック割り当てタイムスロット（６００）とし、従来のタイムスロットの枠を無視して通信を行うのは前記の実施形態と同じだが、この方式ではデータ信号（６０１）の送信に対して受信端末はＭａｃ層Ａｃｋ（４２２）を返す。 Here, the case where the data signal (601) is transmitted from the base station (100) to the terminal (203) is shown. A plurality of time slots are combined into one block allocation time slot (600), and communication is performed while ignoring the conventional time slot frame. However, in this method, the data signal (601) is transmitted. In response to the transmission, the receiving terminal returns a Mac layer Ack (422).
　その後、データ信号（６０１）の転送を行う。このような転送を繰り返して端末（２０３）までデータ信号（６０１）を送信し、端末（２０３）は基地局（１００）に対してＡｃｋ信号（６０２）を返信する。 After that, the data signal (601) is transferred. Such a transfer is repeated to transmit the data signal (601) to the terminal (203), and the terminal (203) returns an Ack signal (602) to the base station (100).
　このＡｃｋ信号（６０２）に対しても受信端末はＭａｃ層のＡｃｋ信号（４２２）を返して信号の伝達を確認する。 In response to this Ack signal (602), the receiving terminal returns the Mac layer Ack signal (422) and confirms signal transmission.
　図１１に示すのように、Ｍａｃ層のＡｃｋ信号（４２２）がＭａｃ層のＡｃｋ信号応答待ち期間（７０３）以内に戻ってこなかった場合は、即座にそのブロック割り当てタイムスロット内で信号の再送を行う。このときのＭａｃ層のＡｃｋ信号応答待ち時間（７０３）は図７のＡｃｋ信号応答待ち時間（７０１）より短い時間に設定される。 As shown in FIG. 11, if the Mac layer Ack signal (422) does not return within the Mac layer Ack signal response waiting period (703), the signal is immediately retransmitted within the block allocation time slot. Do. The Ack signal response waiting time (703) of the Mac layer at this time is set to a time shorter than the Ack signal response waiting time (701) of FIG.
　第２の実施形態での信号未達情報（６０３）を基地局に伝えるプロトコルの例を図１２に示す。 FIG. 12 shows an example of a protocol for transmitting the signal unachieved information (603) in the second embodiment to the base station.
　ここでは端末（２０２）から端末（２０３）への通信が失敗した場合を示す。各端末はブロック割り当てタイムスロット（６００）の先頭からタイマーによる測定を行い、自身が基地局からのデータ信号（６０１）を受信し、かつ転送先の端末からのＡｃｋ信号（６０２）をＡｃｋ信号応答待ち時間（７０４）内に受信できなかった場合は、信号未達情報（６０３）を基地局（１００）に送る。 Here, a case where communication from the terminal (202) to the terminal (203) has failed is shown. Each terminal performs a measurement using a timer from the head of the block allocation time slot (600), and receives a data signal (601) from the base station, and sends an Ack signal (602) from the transfer destination terminal as an Ack signal response. If the signal cannot be received within the waiting time (704), signal unreachable information (603) is sent to the base station (100).
　図１２では端末（２０２）はデータ信号（６０１）送信後、端末（２０３）からのＭａｃ層Ａｃｋ（４２２）がＭａｃ層Ａｃｋ応答待ち時間（７０３）内に返ってこなかったため、信号の再送を行った。この再送に対するＭａｃ層Ａｃｋ応答待ち時間（７０３）中にＡｃｋ信号応答待ち時間（７０４）のタイムアウトが発生したため、信号未達情報（６０３）を基地局（１００）に送信する。 In FIG. 12, after transmitting the data signal (601), the terminal (202) does not return the Mac layer Ack (422) from the terminal (203) within the Mac layer Ack response waiting time (703). It was. Since the timeout of the Ack signal response waiting time (704) occurred during the Mac layer Ack response waiting time (703) for this retransmission, the signal unreachable information (603) is transmitted to the base station (100).
　図１０～図１２における中継局・端末の信号送信フローチャートを図２１に、信号転送フローチャートを図２２に示す。 FIG. 21 shows a signal transmission flowchart of the relay station / terminal in FIGS. 10 to 12, and FIG. 22 shows a signal transfer flowchart.
　上述の実施形態では通信失敗による再送発生時には、データ信号（６０１）宛先の端末（２００）から基地局（１００）までのＡｃｋ信号（６０２）返信を次のスーパーフレーム（５００）のブロック割り当てタイムスロット（６００）にて行ってきた。 In the above-described embodiment, when retransmission occurs due to communication failure, the Ack signal (602) reply from the data signal (601) destination terminal (200) to the base station (100) is returned to the block allocation time slot of the next superframe (500). (600).
　しかしホップ段数が少ない場合や、再送スロット（５０２）が充分な数設定されている場合、データ信号（６０１）の再送のみならずＡｃｋ信号（６０２）の返信も再送スロット（５０２）内で行うことができる。 However, when the number of hop stages is small or when a sufficient number of retransmission slots (502) are set, not only retransmission of the data signal (601) but also return of the Ack signal (602) should be performed within the retransmission slot (502). Can do.
　この場合、データ信号（６０１）の再送と同様に端末（２００）は再送スロット（５０２）においてまず周囲の他の端末が再送スロット（５０２）を使用していないかランダムな遅延時間後のキャリアセンスにより確認し、未使用ならばＡｃｋ信号（６０２）の送信を行う。この手順を再送スロット（５０２）中に繰り返すことにより基地局（１００）までＡｃｋ信号（６０２）を伝達する。 In this case, similarly to the retransmission of the data signal (601), the terminal (200) first detects in the retransmission slot (502) whether the other neighboring terminals are not using the retransmission slot (502) or carrier sense after a random delay time. If not used, an Ack signal (602) is transmitted. By repeating this procedure during the retransmission slot (502), the Ack signal (602) is transmitted to the base station (100).
　上述の実施形態では、再送データ信号（６０４）は再送スロット（５０２）を用いて送信し、Ａｃｋ信号（６０２）のみブロック割り当てタイムスロット（６００）を用いて返信していた。 In the above-described embodiment, the retransmission data signal (604) is transmitted using the retransmission slot (502), and only the Ack signal (602) is returned using the block allocation time slot (600).
　しかし、再送スロット（５０２）が十分な数設定されていない場合、1スーパーフレーム内の再送スロット（５０２）のみでは宛先の端末にデータ信号（６０１）が到達しない場合がある。 However, if a sufficient number of retransmission slots (502) are not set, the data signal (601) may not reach the destination terminal with only the retransmission slots (502) in one superframe.
　これに対し、本実施例では再送データ信号（６０４）の送信もブロック割り当てタイムスロット（６００）を用いる場合について示す。図１３にブロック割り当てタイムスロットを用いて信号再送を行う場合のプロトコルの例を示す。 On the other hand, in this embodiment, the case where the retransmission data signal (604) is transmitted also uses the block allocation time slot (600) will be described. FIG. 13 shows an example of a protocol when signal retransmission is performed using block allocation time slots.
　ここでは基地局（１００）から端末（２０１）、端末（２０２）を経由して端末（２０３）にデータ信号（６０１）を送り、その過程の端末（２０２）から端末（２０３）への通信が失敗した場合について説明する。端末（２０２）は端末（２０３）からのＡｃｋ信号（６０２）を受信できなかったことから、前回のブロック割り当てタイムスロット（６００）での通信失敗を認識し、信号再送待ち状態となっている。 Here, a data signal (601) is sent from the base station (100) to the terminal (203) via the terminal (201) and the terminal (202), and communication from the terminal (202) to the terminal (203) in the process is performed. The case of failure will be described. Since the terminal (202) could not receive the Ack signal (602) from the terminal (203), the terminal (202) recognizes the communication failure in the previous block allocation time slot (600) and is in a signal retransmission waiting state.
　この状態でブロック割り当てタイムスロット（６００）を迎えたとき、端末（２０２）はまずは通常と同じようにタイムスロットの先頭から信号待ち受け状態で待機する。タイムスロット先頭からスロット未使用確認期間（７０２）が過ぎても端末（２０１）からのデータ信号（６０１）が受信されなかった場合、端末（２０２）はこのブロック割り当てタイムスロット（６００）でのデータ信号通信はないと判断し、端末（２０３）に再送データ信号（６０４）を送る。 In this state, when the block allocation time slot (600) is reached, the terminal (202) first waits in a signal waiting state from the beginning of the time slot as usual. If the data signal (601) is not received from the terminal (201) even after the slot unusedness confirmation period (702) has passed from the beginning of the time slot, the terminal (202) transmits data in this block allocation time slot (600). It is determined that there is no signal communication, and a retransmission data signal (604) is sent to the terminal (203).
　その後、端末（２０３）は通常の通信と同様に端末（２０３）からのＡｃｋ信号（６０２）を受信し基地局（１００）に送る。これにより１つのブロック割り当てタイムスロットにおいて再送データ信号（６０４）の送信とＡｃｋ信号（６０２）の返信が完了する。図１３における中継局・端末の信号再送フローチャートを図２３に示す。 After that, the terminal (203) receives the Ack signal (602) from the terminal (203) and sends it to the base station (100) in the same manner as normal communication. This completes the transmission of the retransmission data signal (604) and the return of the Ack signal (602) in one block allocation time slot. FIG. 23 shows a signal retransmission flowchart of the relay station / terminal in FIG.
　上述の実施形態では通信失敗による再送発生時には、データ宛先の端末（２００）から基地局（１００）までのＡｃｋ信号（６０２）返信を次のブロック割り当てタイムスロット（６００）もしくは再送スロット（５０２）を用いて行ってきた。 In the above-described embodiment, when retransmission occurs due to communication failure, the Ack signal (602) from the data destination terminal (200) to the base station (100) is sent back to the next block allocation time slot (600) or retransmission slot (502). I went with it.
　しかし、マルチホップ通信環境では、端末は自身がデータ信号の宛先になるとき以外に他の端末が宛先の通信で中継局として通信を行う場合がある。このとき、本来の通信に対するＡｃｋ信号に自身の通信に対するＡｃｋ信号を加えて基地局（１００）に送ることで新たな通信を起こすことなくＡｃｋ信号の基地局への伝達を行うことができる。 However, in a multi-hop communication environment, a terminal may communicate as a relay station in communication with a destination other than when the terminal itself becomes a data signal destination. At this time, by adding the Ack signal for its own communication to the Ack signal for the original communication and sending it to the base station (100), the Ack signal can be transmitted to the base station without causing a new communication.
　他の端末への中継を通じてＡｃｋ信号を返信する例を、図1４を用いて説明する。図1４の(a)では基地局（１００）から端末（２０１），端末（２０２）を経由して端末（２０４）に信号を送信している。このとき通信の過程で再送が発生することで端末（２０４）から基地局（１００）へのＡｃｋ信号伝達がブロック割り当てタイムスロット（６００）内で完結しなかった場合、端末（２０４）は基地局（１００）へのＡｃｋ信号（６０２）送信待ちの状態となる。 An example of returning an Ack signal through relay to another terminal will be described with reference to FIG. In (a) of FIG. 14, a signal is transmitted from the base station (100) to the terminal (204) via the terminal (201) and the terminal (202). At this time, when retransmission occurs in the process of communication and Ack signal transmission from the terminal (204) to the base station (100) is not completed within the block allocation time slot (600), the terminal (204) The Ack signal (602) to (100) is awaiting transmission.
　この状態で、図１４（ｂ）のように新たに基地局（１００）から端末（２０１、２０３，２０４）を経由して端末（２０５）へのデータ信号（６０１）通信が発生した場合、端末（２０４）は端末（２０５）から基地局（１００）へのＡｃｋ信号（６０２）を中継する過程において、端末（２０５）から受信したＡｃｋ信号（６０２）に自身の前回の通信に対するＡｃｋ情報を追記した複合Ａｃｋ信号（６０６）を作成し、それを端末（２０３）に送信する。この複合Ａｃｋ信号（６０６）は通常のＡｃｋ信号と同様に端末（２０１）を経由して基地局（１００）に送られる。基地局はこの複合Ａｃｋ信号（６０６）を解析し、端末（２０５）宛の通信のみでなく端末（２０４）宛の通信に対するＡｃｋ情報も含んでいることを確認し、両方の通信が終了したことを記録する。 In this state, when data signal (601) communication is newly generated from the base station (100) to the terminal (205) via the terminal (201, 203, 204) as shown in FIG. (204) adds Ack information for its previous communication to the Ack signal (602) received from the terminal (205) in the process of relaying the Ack signal (602) from the terminal (205) to the base station (100). The composite Ack signal (606) is generated and transmitted to the terminal (203). This composite Ack signal (606) is sent to the base station (100) via the terminal (201) in the same manner as a normal Ack signal. The base station analyzes this composite Ack signal (606), confirms that it includes not only the communication addressed to the terminal (205) but also the Ack information for the communication addressed to the terminal (204), and that both communication have ended. Record.
　図１４における中継局・端末の信号送信フローチャートを図２４に示す。 FIG. 24 shows a signal transmission flowchart of the relay station / terminal in FIG.
　上述の実施例ではマルチホップ通信が中継局で途絶した場合、途絶した端末から再送を行っていた。 In the above-described embodiment, when multi-hop communication is interrupted at the relay station, retransmission is performed from the disconnected terminal.
　しかし、近傍の複数の端末で通信途絶が発生した場合、それぞれの端末の再送が重なり通信効率が悪くなる場合がある。本実施例では通信途絶が生じた場合、次のブロック割り当てタイムスロット（６００）において基地局（１００）から再び同じデータ信号（６０１）を送付する場合について説明する。 However, when communication interruption occurs in a plurality of nearby terminals, retransmission of each terminal may overlap and communication efficiency may deteriorate. In this embodiment, a case where the same data signal (601) is sent again from the base station (100) in the next block allocation time slot (600) when communication interruption occurs will be described.
　基地局（１００）はデータ信号（６０１）送信後に信号未達情報（６０３）を受け取った場合、信号再送モードで待機する。その状態で、次のブロック割り当てタイムスロット（６００）を迎えたら、データ信号（６０１）の再送を行う。このとき、前回の信号送信よりも通信信頼性向上のための手法を用いることも可能である。通信信頼性向上のための手法としては、具体的には信号送信出力の増加、誤り訂正符号の付加、通信チャネルの変更などがある。 When the base station (100) receives the signal unreachable information (603) after transmitting the data signal (601), the base station (100) stands by in the signal retransmission mode. In this state, when the next block allocation time slot (600) is reached, the data signal (601) is retransmitted. At this time, it is also possible to use a technique for improving communication reliability compared to the previous signal transmission. Specific techniques for improving communication reliability include increasing signal transmission output, adding error correction codes, changing communication channels, and the like.
　上述の実施例では、マルチホップ通信が中継局で途絶した場合次のブロック割り当てタイムスロットにおいて基地局から再び同じ信号を送付した。 In the above embodiment, when the multi-hop communication is interrupted at the relay station, the same signal is sent again from the base station in the next block allocation time slot.
　しかし、データ送信間隔がスーパーフレームの長さと同じ場合、次のブロック割り当てタイムスロットでは別のデータを送信する必要がある。 However, if the data transmission interval is the same as the superframe length, it is necessary to transmit another data in the next block allocation time slot.
　本実施例では、中継局で通信が途絶した場合、基地局は次に送るデータに前回送信したデータを合わせて送信することにより端末に２回分のデータを届ける方法を説明する。 In this embodiment, when communication is interrupted at a relay station, a method will be described in which the base station sends data to the terminal twice by transmitting the data to be transmitted next together with the previously transmitted data.
　基地局（１００）はデータ信号（６０１）送信後に信号未達情報（６０３）を受け取った場合、信号再送モードで待機する。その状態でデータ送信間隔（５０３）経過後、次のデータ送信時に前に送ったデータ信号（６０１）と合わせて２回分のデータをもつデータ信号を送る。中継局は通常のデータ信号と同様にそのデータ信号を宛先の端末まで送信する。宛先の端末ではパケットの内容を調べ、2回分のデータが含まれていることを確認し、２回分のデータを受け取ったことを示すＡｃｋ信号（６０２）を基地局（１００）に返す。基地局（１００）はこのＡｃｋ信号（６０２）を受信したら２回分のデータ送信が完了したことを記録し、通信を終了する。 When the base station (100) receives the signal unreachable information (603) after transmitting the data signal (601), the base station (100) stands by in the signal retransmission mode. In this state, after the data transmission interval (503) elapses, a data signal having two times of data is sent together with the data signal (601) sent before the next data transmission. The relay station transmits the data signal to the destination terminal in the same way as a normal data signal. The destination terminal checks the contents of the packet, confirms that data for two times is included, and returns an Ack signal (602) indicating that data for two times has been received to the base station (100). When receiving the Ack signal (602), the base station (100) records that data transmission for two times is completed, and ends the communication.
　上述の実施例では、マルチホップ通信の途上で通信が途切れた場合、基地局から新たに信号を再送する方法を示した。しかし通信途絶が通信環境に起因するものであれば、信号を再送しても同じように通信途絶を起こす可能性がある。 In the above-described embodiment, when communication is interrupted in the course of multi-hop communication, a method of newly resending a signal from the base station has been shown. However, if the communication disruption is caused by the communication environment, the communication disruption may occur in the same manner even if the signal is retransmitted.
　本実施例では通信途絶が発生した場合、マルチホップの経路を変更して信号を再送することで通信途絶の繰り返しを防ぐことを目的とする。 The purpose of this embodiment is to prevent repeated communication interruption by changing a multi-hop route and retransmitting a signal when communication interruption occurs.
　具体的な例を図１５を用いて説明する。 A specific example will be described with reference to FIG.
　図15(a)のように基地局（１００）から端末（２０１，２０２）を通じて端末（２０４）に信号を送る途上で、端末（２０２）と端末（２０４）の通信が失敗した場合、基地局（１００）は端末（２０２）より信号未達情報（６０３）を受け取る。このとき、基地局（１００）は自身が持つルート情報より端末（２０２）と端末（２０４）の間の通信が失敗したことを認識し、端末（２０２）を経由しないルートを新たに設定する。ここでは図15 (b)に示すように端末（２０１）、端末（２０３）を経由して端末（２０４）に至るルートを新たに設定したとする。 When communication between the terminal (202) and the terminal (204) fails while a signal is being transmitted from the base station (100) to the terminal (204) through the terminals (201, 202) as shown in FIG. (100) receives signal unreachable information (603) from the terminal (202). At this time, the base station (100) recognizes that communication between the terminal (202) and the terminal (204) has failed from its own route information, and newly sets a route that does not pass through the terminal (202). Here, it is assumed that a route to the terminal (204) via the terminal (201) and the terminal (203) is newly set as shown in FIG. 15 (b).
　このとき、まず端末（２０１，２０２，２０４）のルートに割り当てていたブロック割り当てタイムスロット（６００）の解除を各端末に通知する。この通知は制御用のチャネル等、通信失敗が起こりにくい手段で経路上の全端末に通知する。あるいは第6の実施形態で述べた通信信頼性の高い方法を用いて通知する。 At this time, first, each terminal is notified of the release of the block allocation time slot (600) allocated to the route of the terminal (201, 202, 204). This notification is sent to all terminals on the route by means such as a control channel that is unlikely to cause communication failure. Alternatively, notification is performed using the method with high communication reliability described in the sixth embodiment.
　次に新規ルート上の端末に新たにタイムスロットのブロック割り当てを行う。 Next, a new time slot block is allocated to the terminal on the new route.
　ここでは端末（２０１，２０３，２０４）に新たなタイムスロット割り当てを行う。これにより通信路状況の悪かったルートが回避されるため、端末（２０４）に通信が届きやすくなる。図１５における基地局のルート再設定動作フローチャートを図２５に示す。 Here, a new time slot is assigned to the terminals (201, 203, 204). As a result, a route having a bad communication path condition is avoided, and communication easily reaches the terminal (204). FIG. 25 is a flowchart of the base station route resetting operation in FIG.
　上述の実施例では、マルチホップ通信の途上で通信が途切れた場合、基地局から新たなルートを設定して再送する方法を示した。しかしルートの再設定のためには複数の通信が発生するため効率が悪いという面もある。 In the above-described embodiment, when communication is interrupted in the course of multi-hop communication, a method of retransmitting a new route from the base station is shown. However, in order to reset the route, a plurality of communications are generated, which is inefficient.
　本実施例では、マルチホップ通信の途上で通信が途切れた場合、その端末を中継局として使用する別の端末への通信に再送用の信号の内容を追記することで再送を行わずにデータを届ける方法を説明する。 In this embodiment, when communication is interrupted in the course of multi-hop communication, data can be transmitted without performing retransmission by adding the content of a signal for retransmission to communication to another terminal that uses the terminal as a relay station. Explain how to deliver.
　具体的な例を図１６を用いて説明する。 A specific example will be described with reference to FIG.
　図１６(a)のように基地局（１００）から端末（２０１，２０２）を経由して端末（２０４）にデータを送付する過程で端末（２０２）と端末（２０４）の通信に失敗した場合、基地局（１００）は端末（２０２）から信号未達情報（６０３）を受け取り信号再送モードで待機する。この状態で宛先である端末（２０４）を経路上に含む通信が次に行われる機会を待つ。 When communication between the terminal (202) and the terminal (204) fails in the process of sending data from the base station (100) to the terminal (204) via the terminals (201, 202) as shown in FIG. The base station (100) receives the signal unreachable information (603) from the terminal (202) and waits in the signal retransmission mode. In this state, it waits for the next opportunity to perform communication including the destination terminal (204) on the route.
　ここで図１６(b)のように端末（２０４）を経由して端末（２０５）にデータ信号（６０１）を送信する機会が来たとき、基地局（１００）は端末（２０５）宛のデータと端末（２０４）宛のデータを併せた複合データ信号（６０７）を作成して端末（２０５）宛に送付する。 Here, when the opportunity to transmit the data signal (601) to the terminal (205) via the terminal (204) as shown in FIG. 16 (b), the base station (100) receives the data addressed to the terminal (205). And a composite data signal (607) in which the data addressed to the terminal (204) is combined and sent to the terminal (205).
　端末（２０４）はその複合データ信号（６０７）を受信したら内容を確認し、自身宛の部分のデータを受け取ったうえで、信号を端末２０５に転送する。このとき、自身宛のデータ部分を削除してデータ信号（６０１）を再構成して端末（２０５）に送ってもよい。 When the terminal (204) receives the composite data signal (607), it confirms the contents, receives the data addressed to itself, and transfers the signal to the terminal 205. At this time, the data portion addressed to itself may be deleted and the data signal (601) may be reconfigured and sent to the terminal (205).
　端末（２０５）は信号の内容を確認して自身宛のデータを受け取り、それに対するＡｃｋ信号（６０２）を端末（２０４）宛に送る。端末（２０４）はそのＡｃｋ信号（６０２）に自身のＡｃｋを追記した複合Ａｃｋ信号（６０６）を端末（２０３，２０１）経由で基地局（１００）まで送る。基地局は複合Ａｃｋ信号（６０６）の内容を確認し、端末（２０５，２０４）それぞれにデータが届いたことを確認して記録し、通信を完了させる。 The terminal (205) confirms the content of the signal, receives data addressed to itself, and sends an Ack signal (602) corresponding thereto to the terminal (204). The terminal (204) sends a composite Ack signal (606) in which its Ack is added to the Ack signal (602) to the base station (100) via the terminals (203, 201). The base station confirms the contents of the composite Ack signal (606), confirms and records that the data has arrived at each of the terminals (205, 204), and completes the communication.
　もし、端末（２０４）に端末（２０５）からのＡｃｋ信号（６０２）が届かなかった場合は、端末（２０４）はＡｃｋ信号応答待ち時間（７０１）後にタイムアウトし、自身のＡｃｋ信号（６０２）を作成して基地局（１００）に送付する。 If the Ack signal (602) from the terminal (205) does not reach the terminal (204), the terminal (204) times out after the Ack signal response waiting time (701), and sends its own Ack signal (602). Create and send to base station (100).
　基地局（１００）はそのＡｃｋ信号（６０２）を受信したら、端末（２０４）宛の通信完了を記録し、端末（２０５）宛の再送モードで待機する。 When the base station (100) receives the Ack signal (602), it records the completion of communication addressed to the terminal (204) and stands by in the retransmission mode addressed to the terminal (205).
　図１６における基地局の動作フローチャートを図２６に示す。 FIG. 26 shows an operation flowchart of the base station in FIG.
１００　　　　　　　　基地局
２００,２０１，２０２，２０３，２０４，２０５，２０６端末
３００　　　　　　　　広域ネットワーク
１０１　　　　　　　　タイムスロット管理機能
１０２　　　　　　　　ネットワーク構成データベース
１０３　　　　　　　　システム同期機能
１０４　　　　　　　　データ通信機能
１０５　　　　　　　　無線通信機能
１０６　　　　　　　　アンテナ
１０７　　　　　　　　広域通信インタフェース
２１１　　　　　　　　同期維持機能
２１２　　　　　　　　システム情報メモリ
２１３　　　　　　　　データ送受信機能
２１４　　　　　　　　無線通信機能
２１５　　　　　　　　アンテナ
２１６　　　　　　　　外部インタフェース
２１７　　　　　　　　外部機器
４００　　　　　　　　タイムスロット
４０１　　　　　　　　送信オフセット
４０２　　　　　　　　パケット送信
４０３　　　　　　　　受信準備
４０５　　　　　　　　Ｍａｃ層Ａｃｋ受信
４２１　　　　　　　　パケット
４２２　　　　　　　　Ｍａｃ層Ａｃｋ
４１１　　　　　　　　受信オフセット
４１２　　　　　　　　パケット受信待ち受け
４１３　　　　　　　　パケット受信
４１４　　　　　　　　Ｍａｃ層Ａｃｋ準備
４１５　　　　　　　　Ｍａｃ層Ａｃｋ送信
５００　　　　　　　　スーパーフレーム
５０１　　　　　　　　通常スロット
５０２　　　　　　　　再送スロット
５０３　　　　　　　　データ送信間隔
６００　　　　　　　　ブロック割り当てタイムスロット
６０１　　　　　　　　データ信号
６０２　　　　　　　　Ａｃｋ信号
６０３　　　　　　　　信号未達情報
６０４　　　　　　　　再送データ信号
６０６　　　　　　　　複合Ａｃｋ信号
６０７　　　　　　　　複合データ信号
７０１　　　　　　　　Ａｃｋ信号応答待ち時間
７０２　　　　　　　　スロット未使用確認期間
７０３　　　　　　　　Ｍａｃ層Ａｃｋ応答待ち期間
７０４　　　　　　　　Ａｃｋ信号応答待ち時間 100 base station 200, 201, 202, 203, 204, 205, 206 terminal 300 wide area network 101 time slot management function 102 network configuration database 103 system synchronization function 104 data communication function 105 wireless communication function 106 antenna 107 wide area communication interface 211 synchronization maintenance Function 212 System information memory 213 Data transmission / reception function 214 Wireless communication function 215 Antenna 216 External interface 217 External device 400 Time slot 401 Transmission offset 402 Packet transmission 403 Reception preparation 405 Mac layer Ack reception 421 Packet 422 Mac layer Ack
411 Reception offset 412 Packet reception standby 413 Packet reception 414 Mac layer Ack preparation 415 Mac layer Ack transmission 500 Super frame 501 Normal slot 502 Retransmission slot 503 Data transmission interval 600 Block allocation time slot 601 Data signal 602 Ack signal 603 Signal unreachable information 604 Retransmitted data signal 606 Composite Ack signal 607 Composite data signal 701 Ack signal response waiting time 702 Slot unused confirmation period 703 Mac layer Ack response waiting period 704 Ack signal response waiting time

Claims (13)

  1. 　複数の端末と基地局を有するＴＤＭＡ(Time division Multiple Access)無線通信システムであって、
    　マルチホップ通信を行う際に、通信経路上の全ての前記端末と前記基地局を1つのグループとし、前記基地局はそのグループに複数の連続したタイムスロットを割り当て、それらのタイムスロットを1つの大きなブロックタイムスロットとみなし、そのブロックタイムスロット内で前記端末及び前記基地局はマルチホップの前段の前記基地局または前記端末のいずれかから送信されてきた信号を直ちにマルチホップ次段の前記端末または前記基地局のいずれかに転送することを繰り返すことを特徴とする無線通信システム。     A TDMA (Time division Multiple Access) wireless communication system having a plurality of terminals and a base station,
    When performing multi-hop communication, all the terminals on the communication path and the base station are grouped together, and the base station assigns a plurality of consecutive time slots to the group, and these time slots are allocated to one large time slot. Assuming a block time slot, the terminal and the base station within the block time slot immediately receive a signal transmitted from either the base station or the terminal at the previous stage of multihop or the terminal at the next stage of multihop or the A wireless communication system characterized by repeating transfer to one of base stations.
  2. 　個別の通信に対するＭａｃ層のアクノレッジ信号を使用せず、信号が宛先の前記端末または前記基地局に到達したときに、信号到達を知らせるアクノレッジ信号を、信号送信時とは逆の経路で送信元の前記端末または前記基地局に送ることで、経路上の前記端末の全てに前記信号の到達を知らせることを特徴とする請求項１記載の無線通信システム。 An Acknowledge signal notifying the arrival of a signal when a signal arrives at the destination terminal or the base station without using an Acknowledge signal of the Mac layer for individual communication is transmitted on the reverse path to the time of signal transmission. The wireless communication system according to claim 1, wherein the arrival of the signal is notified to all of the terminals on a route by sending to the terminal or the base station.
  3. 　個別の通信に対してはＭａｃ層のアクノレッジ信号を使用して通信の成否を確認し、かつ、前記信号が宛先の前記端末または前記基地局に到達したときに、信号到達を知らせるアクノレッジ信号を、信号送信時とは逆の経路で送信元の前記端末または前記基地局に送ることで、経路上の前記端末全てに前記信号の到達を知らせるアクノレッジ信号を使用することを特徴とする請求項１記載の無線通信システム。 For individual communication, confirm the success or failure of communication using an acknowledgment signal of the Mac layer, and when the signal reaches the destination terminal or the base station, an acknowledge signal that informs the arrival of the signal, The acknowledge signal is used to notify all of the terminals on the path of arrival of the signal by sending the signal to the terminal or the base station of the transmission source through a path opposite to that at the time of signal transmission. Wireless communication system.
  4. 　マルチホップ通信において宛先の前記端末まで信号が到達しなかった場合、その通信で障害が起こった通信路を含まない新たな経路を前記基地局は設定し、その通信経路上の全ての前記端末および前記基地局に複数の連続したタイムスロットを割り当て、それらのタイムスロットを1つの大きなブロックタイムスロットとみなして通信を行うことを特徴とする請求項１記載の無線通信システム。 If the signal does not reach the destination terminal in multi-hop communication, the base station sets a new path that does not include the communication path in which the communication has failed, and all the terminals on the communication path The wireless communication system according to claim 1, wherein a plurality of continuous time slots are allocated to the base station, and communication is performed by regarding these time slots as one large block time slot.
  5. 　マルチホップ通信において宛先の前記端末まで信号が到達しなかった場合、その通信で障害が起こった通信路を含まない新たな経路を前記基地局は設定し、その通信経路上の全ての前記端末および前記基地局に複数の連続したタイムスロットを割り当て、それらのタイムスロットを1つの大きなブロックタイムスロットとみなして通信を行うことを特徴とする請求項２記載の無線通信システム。 If the signal does not reach the destination terminal in multi-hop communication, the base station sets a new path that does not include the communication path in which the communication has failed, and all the terminals on the communication path The wireless communication system according to claim 2, wherein a plurality of continuous time slots are allocated to the base station, and communication is performed by regarding these time slots as one large block time slot.
  6. 　マルチホップ通信において宛先の前記端末まで信号が到達しなかった場合、その通信で障害が起こった通信路を含まない新たな経路を前記基地局は設定し、その通信経路上の全ての前記端末および前記基地局に複数の連続したタイムスロットを割り当て、それらのタイムスロットを1つの大きなブロックタイムスロットとみなして通信を行うことを特徴とする請求項３記載の無線通信システム。 If the signal does not reach the destination terminal in multi-hop communication, the base station sets a new path that does not include the communication path in which the communication has failed, and all the terminals on the communication path The wireless communication system according to claim 3, wherein a plurality of continuous time slots are allocated to the base station, and communication is performed by regarding these time slots as one large block time slot.
  7. 　複数の端末と通信するＴＤＭＡ無線通信システムの無線通信基地局であって、
    　システムのタイムスロットを管理し割り当てる機能を持ち、マルチホップ通信に対しては、通信経路上の全ての前記端末と基地局を1つのグループとし、そのグループに複数の連続したタイムスロットを割り当て、それらのタイムスロットを1つの大きなブロックタイムスロットとみなす無線通信基地局。     A wireless communication base station of a TDMA wireless communication system that communicates with a plurality of terminals,
    It has a function to manage and allocate system time slots. For multi-hop communication, all the terminals and base stations on the communication path are grouped together, and a plurality of consecutive time slots are allocated to these groups. A wireless communication base station that considers a time slot as one large block time slot.
  8. 　マルチホップ通信の宛先の前記端末へ信号が未達であると判った場合、別のブロックタイムスロットを用いて信号の再送を行うことを特徴とする請求項７記載の無線通信基地局。 8. The radio communication base station according to claim 7, wherein when it is determined that the signal has not reached the terminal that is the destination of the multi-hop communication, the signal is retransmitted using another block time slot.
  9. 　マルチホップ通信において宛先の前記端末に信号が未達であることが判った場合、その通信で障害が起こった通信路を含まない新たな経路を設定し、その通信経路上の全ての前記端末と基地局に複数の連続したタイムスロットを割り当て、それらのタイムスロットを1つの大きなブロックタイムスロットとみなして通信を行うことを特徴とする請求項７記載の無線通信基地局。 When it is found that the signal has not reached the destination terminal in multi-hop communication, a new path not including the communication path in which the communication has failed is set, and all the terminals on the communication path 8. The radio communication base station according to claim 7, wherein a plurality of continuous time slots are allocated to the base station, and communication is performed by regarding these time slots as one large block time slot.
  10. 　マルチホップ通信において宛先の前記端末に信号が未達であることが判った場合、その通信で障害が起こった通信路を含まない新たな経路を設定し、その通信経路上の全ての前記端末と基地局に複数の連続したタイムスロットを割り当て、それらのタイムスロットを1つの大きなブロックタイムスロットとみなして通信を行うことを特徴とする請求項８記載の無線通信基地局。 When it is found that the signal has not reached the destination terminal in multi-hop communication, a new path not including the communication path in which the communication has failed is set, and all the terminals on the communication path 9. The radio communication base station according to claim 8, wherein a plurality of continuous time slots are allocated to the base station, and communication is performed by regarding these time slots as one large block time slot.
  11. 　複数の端末と基地局を有するＴＤＭＡ無線通信システムの一部を構成する無線通信端末であって、
    　マルチホップ通信時に、前記基地局から複数の連続したタイムスロットを割り当てられ、それらのタイムスロットを1つの大きなブロックタイムスロットとする指示を受けた場合、ブロックタイムスロット内で受信待機を行い、マルチホップ前段の端末もしくは前記基地局から信号を受けたら即座に次段のマルチホップ端末へ信号を転送する機能を持つことを特徴とする無線通信端末。     A wireless communication terminal forming part of a TDMA wireless communication system having a plurality of terminals and a base station,
    During multi-hop communication, when a plurality of consecutive time slots are allocated from the base station and an instruction is given to make those time slots one large block time slot, reception is waited within the block time slot, and multi-hop communication is performed. A radio communication terminal having a function of transferring a signal to a next-stage multi-hop terminal immediately upon receiving a signal from a previous-stage terminal or the base station.
  12. 　ブロックタイムスロット内での通信にはＭａｃ層のアクノレッジ信号を使用せず、マルチホップ前段の端末もしくは前記基地局から信号送信後は即座に受信待ち受け状態で待機し、マルチホップの経路を逆に送られてくるアクノレッジ信号を受信することで信号の到達を確認することを特徴とする請求項１１記載の無線通信端末。 Acknowledgment signals in the Mac layer are not used for communication within the block time slot, but immediately after receiving the signal from the terminal in the multi-hop stage or the base station, the mobile station stands by in the reception waiting state and sends the multi-hop route in reverse. 12. The wireless communication terminal according to claim 11, wherein arrival of the signal is confirmed by receiving an acknowledge signal.
  13. 　ブロックタイムスロット内で信号送信後、一定時間内に宛先の前記端末から逆の経路で送られてくるアクノレッジ信号を受信できなかった場合、宛先の前記端末または前記基地局まで信号が未達であることを知らせる信号を、マルチホップ通信の逆の経路に送る機能を持つことを特徴とする請求項１２記載の無線通信端末。 If an acknowledge signal sent from the destination terminal through the reverse path within a certain time after signal transmission within a block time slot cannot be received, the signal has not reached the destination terminal or the base station. 13. The wireless communication terminal according to claim 12, wherein the wireless communication terminal has a function of sending a signal notifying of this to a reverse route of multi-hop communication.
PCT/JP2012/068142 2012-07-18 2012-07-18 Wireless communication system, wireless communication base station, and wireless communication terminal WO2014013560A1 (en)

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