JP2011029876A - Radio communication method and system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that slot assignment requests used in communication between two basic networks performing communication by mutually different frequencies of TDMA systems interfere with another communication. <P>SOLUTION: In a radio communication method, a specified time slot, namely one portion of time slots assigned to slave node groups 110, 120, 210, 220, is divided into a plurality of sub time slots, the respective slave nodes 110, 120, 210, 220 use the sub time slot to transmit a communication request, and master nodes 100, 200 receive the communication request, thus assigning time slots to any source slave node of the communication request from the time slot assigned to the slave node groups 110, 120, 210, 220 by the master nodes 100, 200. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a wireless communication method and system for performing communication using TDMA (Time Division Multiple Access), and more particularly to a wireless communication method and system for defining communication timing of slave nodes.

  In recent years, technology development has been carried out to establish various communication networks by establishing communication lines between wireless devices.

Examples of related techniques include Patent Document 1 and Patent Document 2.
The technique described in Patent Document 1 uses a TDMA system as a multiplexing method for sharing a radio band of each node constituting a network, that is, a radio frequency. The TDMA method is a multiple access method in which a radio frequency band to be used is divided by a time axis, a slot is managed as a unit, and communication between nodes is assigned to each slot, whereby a radio frequency band is shared by a plurality of nodes. It is.
Further, Patent Document 1 establishes a communication line (network) between a master node (control device) and a slave node (device), and enables communication between the master node (control device) and the slave node (device). Yes. Patent Document 1 proposes to use a wireless line in place of a wired trunk line in order to perform communication between at least two networks. Specifically, it is disclosed that network information is transmitted and received using the degree of overlap between two networks determined by the distance between control devices respectively disposed in two adjacent networks. For example, in the case of a visible overlap that is close enough to make two networks visible, network information is passed directly between the two control devices, and in the case of an invisible overlap, one control device controls the other. Network information is passed using devices in the network of devices. Furthermore, when the overlap between two networks is small, network information is passed through a child network composed of devices in both networks.
Here, the network information includes a router / control device identifier, a sequence number, the number of connected network devices, and the like.

Patent Document 2 describes an ad hoc network that does not require a master node. Furthermore, a technique is described in which each node constructing an ad hoc network can autonomously select the same use frequency band.
The technique described in Patent Literature 2 can communicate information via a plurality of nodes (relay nodes) and can communicate with another node that is not within the communication range.

JP 2005-537692 A JP 2006-254209 A

  In the wireless communication system in which a network is constructed by a plurality of nodes as in Patent Document 1 and Patent Document 2 described above, it is desirable to control the timing of transmitting communication.

  However, in a wireless communication system in which a slave node makes a communication request to a master node as in Patent Document 1, the slave node makes a communication request to the master node at the timing when the slave node communicates with itself. In this case, interference (collision, collision) occurs when a plurality of slave nodes transmit communication requests simultaneously. In addition, when it interferes with communication other than the communication request, it also affects the communication at the interference destination.

  Furthermore, as in Patent Document 1, when network information is transmitted and received between different networks, it is necessary to generate a large amount of communication requests in order to transmit and receive a large amount of traffic. The probability that the communication request of the control device or device) interferes.

  For this reason, a delay in communication speed and deterioration in communication efficiency occur due to the system load of the relay device and the concentration of communication.

  On the other hand, in the ad hoc connection as in Patent Document 2, some kind of communication is always performed in order to expand the network, and there is a high probability that the communication request described above interferes.

  Accordingly, an object of the present invention is to solve the above-described problems and provide a wireless communication method capable of efficiently processing a communication request transmitted from a slave node in a wireless communication system performing TDMA communication.

  Another object of the present invention is to provide a wireless communication method capable of efficiently processing a communication request originated by a relay node used for wireless communication between a plurality of networks.

  The wireless communication method of the present invention is a communication method in which a master node and a slave node group composed of a plurality of slave nodes communicate with each other through a time slot assigned thereto, and one of the time slots assigned to the slave node group. A specific time slot is divided into a plurality of sub time slots, each slave node transmits a communication request using the sub time slot, and the communication request is received by the master node. A node is characterized in that a time slot is assigned to a slave node that has made the communication request from a time slot assigned to the slave node group.

  ADVANTAGE OF THE INVENTION According to this invention, the communication request transmitted from a slave node can be processed efficiently in the radio | wireless communications system which performs communication of a TDMA system. In addition, the interference of communication requests can be reduced.

1 is a diagram schematically showing a communication system according to an embodiment of the present invention. It is a figure which shows the structure of the super frame used with the communication system of FIG. It is a time chart explaining the super frame used in the communication system which concerns on this invention. It is a figure which illustrates the division | segmentation of the slot of a super frame. It is a flowchart which shows operation | movement of the communication system which concerns on this invention.

A first embodiment of the present invention will be described first with reference to FIG.
In this embodiment, it is assumed that a radio that can communicate in different frequency bands and that can instantaneously change the used frequency band can be used as any of a master node, a slave node, and a relay node. . In addition, it is assumed that the various nodes (wireless devices) are synchronized with each other using a GPS function or the like, and the communication method also uses the TDMA method.

  FIG. 1 is a configuration diagram illustrating a communication system according to a first embodiment of the present invention. The illustrated communication system performs communication using a first radio frequency F1 (ie, radio frequency band F1). A first basic network 10 to be performed and a second basic network 20 to perform communication using a second radio frequency (radio frequency band) F2 different from the first radio frequency F1 are included. As illustrated, the first basic network 10 and the second basic network 20 have partially overlapping service areas.

  The first basic network 10 includes a master node 100, a slave node 110, and a relay node 120. In practice, the first basic network 10 may include a large number of slave nodes, but only a single slave node 110 and a relay node 120 are shown here for the sake of simplicity. Has been. The relay node 120 operates as a relay node for connecting to the second basic network 20 and is selected from a plurality of slave nodes arranged in overlapping service areas. As illustrated, the relay node 120 can communicate with the first master node 100 using the radio frequency F1.

  More specifically, the first master node 100 has a role of constructing the first basic network 10, determines a use frequency band (F1 in this case) of the first basic network 10, and sets the slave node 110 and the first master node 100. Management of information such as one relay node 120 or communication timing is performed. Furthermore, the first master node 100 transmits network management information (slot allocation information and the like) such as communication timing and various information to each node by broadcasting. The slave node 110 and the first relay node 120 are assigned a slot from the master node 100 by transmitting a communication request (slot assignment request information) to the master node 100, and at the timing of the assigned slot. Send (outgo).

  On the other hand, the second basic network 20 includes a second master node 200, a slave node 210, and a second relay node 220. The slave node in the second basic network 20 can communicate with the second master node 200 using the radio frequency F2, and the second relay node 220 is a slave node that can communicate with the second master node 200. Of these, the slave nodes arranged in the overlapping service areas are selected. That is, the second relay node 220 operates as a relay node for connecting to the first basic network 10. Similarly to the first master node 100, the second master node 200, the slave node 210, and the relay node 220 also transmit information such as network management information (slot allocation information) and communication requests (slot allocation request information). (send.

  As is clear from the above, the first and second master nodes 100 and 200 have a function and means for selecting the first and second relay nodes, respectively. Can be realized.

  Further, the illustrated first relay node 120 has a function of converting the radio frequency F1 of the signal received from the first master node 100 into the radio frequency F2 of the second basic network 20, while the second The relay node 220 has a function of converting the radio frequency F2 of the signal received from the second master node 200 into the radio frequency F1 of the first basic network 10.

  Furthermore, if the first and second relay nodes 120 and 220 only convert the frequency and do not identify, decode, encode, etc. the received signal, the configuration can be simplified. . Similarly, if the first and second relay nodes 120 and 220 adjust the transmission timing of communication using the built-in memory buffer, the communication efficiency between the master nodes can be improved.

  Note that the first and second slave nodes 110 and 210 may be any wireless device as long as the communication method used in each basic network 10 and 20 can be used, including general wireless devices. For example, a transceiver dedicated to voice communication or a large fixed radio (station) may be used.

  Communication between the master nodes 100 and 200 and the slave nodes 110 and 210 in the first and second basic networks 10 and 20 is performed by a TDMA system using radio frequencies F1 and F2 as carrier waves.

  Referring to FIG. 2, an example of a super frame used in the TDMA system is shown. The illustrated super frame is composed of 20 slots. Each slot has the same interval (time). “M” and “S” shown in the slots are marks indicating nodes having the transmission right of the used frequency band at the timing of each slot, “M0 to M9” are master nodes, and “S0 to S9” are Indicates a slave node (relay node). That is, the illustrated superframe is configured such that the master node has a transmission right for 10 slots, the slave node has a transmission right for 10 slots, and the transmission rights between the master node and the slave node are alternately switched. Indicates that Since various nodes including the master nodes 100 and 200 are synchronized, the superframe is also synchronized.

  That is, in the basic networks 10 and 20 including the master nodes 100 and 200 shown in FIG. 1, each master node 100 and 200 uses a superframe to time-divide specific radio frequencies F1 and F2 assigned thereto. , The network management information is transmitted using the broadcast channel (BCC), and the slave node communicates with the master node by referring to the network management information, so that a plurality of nodes are simultaneously connected (multiple connection, multiple access), Basic networks 10 and 20 are constructed.

  When performing communication between basic networks, it is necessary to switch the two relay nodes 120 and 220 from the state of communication within each basic network. For this reason, in the illustrated embodiment, BCCs are arranged at positions that are different from each other in time, the frequency of the relay node is switched using the BCC, various information is transmitted, and the communication is performed. We are trying to improve efficiency.

Referring to FIG. 3, a super frame indicating a communication request (SCH, slot allocation request information) is shown.
As shown in FIG. 3, the TDMA communication of this embodiment repeats a super frame. Each super frame is divided into 20 slots “M0” to “S9”. Each slot is used as various channels (BCC (Broadcast channel), SCH (service channel), TCH (traffic channel), RCH (response channel), etc.) between nodes.
Further, among the slots constituting the superframe shown in FIG. 3, “S2” and “S3” slots are reserved for SCH. Further, the “S2” and “S3” slots are divided and used as four subslots.
The “M6” and “M7” slots are reserved for BCC, and the remaining slots are used for transmission of TCH or the like.

  The SCH is a channel that makes a slot allocation request to a node (slot manager) that manages slots. In this embodiment, the slave nodes 110 and 210 and the relay nodes 120 and 220 transmit communication request information including slot allocation information, and the master nodes 100 and 200 receive the communication request information.

  The BCC is a channel that is used as a broadcast channel and transmits information including allocation information of each slot of the superframe. In the present embodiment, the BCC “M6” and “M7” slots are assigned to the master node 100, 200 transmits network management information, and is used as a slot for the slave nodes 110 and 210 and the relay nodes 120 and 220 to receive.

  The TCH is a channel for transmitting communication data (actual data) between the nodes. In this embodiment, the slave nodes 110 and 210 and the relay nodes 120 and 220 and the master nodes 100 and 200 are used for communication.

Here, taking the communication request of the slave node 110 as an example, the operation of the first basic network 10 will be described.
FIG. 4 is a diagram illustrating division of a superframe slot. This figure is an enlarged view of a part of the superframe shown in FIG. 3, and is the “M3” slot to “S4” slot portion. In the present embodiment, two SCH slots (“S2”, “S3”) are provided and further divided into subslots to reduce SCH interference.
Referring to FIG. 4, the “S3” slot is divided into two. Furthermore, the frame transmitted at the timing of the divided subslot (1/2 slot) has a configuration delimited by a guard which is a general frame configuration.
That is, slot allocation information (SCH) that normally uses one slot can be transmitted using a 1/2 slot by using a 1/2 slot allocation frame.

FIG. 5 is a flowchart illustrating communication request communication of the slave node 110.
The master node 100 and the slave node 110 exist at positions where they can communicate with each other, and form a topology capable of wireless link.
The master node 100 uses the BCC slot of the superframe and transmits a BCC including slot allocation information (step S401).

The slave node 110 receives the BCC transmitted from the master node 100 and analyzes the content described in the BCC. That is, slot allocation information is acquired. The slave node 110 recognizes information such as allocation of various slots, instructions from the master node, and the like based on the analysis.
When the slave node 110 needs a slot, for example, when it communicates, the slave node 110 issues a communication request including the timing of the subslot of “S2” or “S3”, that is, the number of slots necessary at the SCH transmission timing. It transmits as SCH (step S402). As shown in FIG. 4, the SCH transmitted here is a slot allocation frame that is 1/2 the length of other frames. That is, two SCHs can be transmitted in one time slot.

  The master node 100 receives the SCH transmitted from the slave node 110 and recognizes the request slot number of the slave node 110. The master node 100 recognizes the recognized request of the slave node 110 and the slot allocation request received from another node, and arbitrarily determines which node in the superframe is assigned radio wave transmission rights. The master node 100 configures the assigned slot allocation instruction (result) as slot allocation information and transmits a BCC (step S403).

  The slave node 110 receives the BCC transmitted from the master node 100, analyzes the contents described in the BCC, and transmits the TCH at the timing of the slot allocated by the master node 100 (step S404).

  Similarly to the slave node 110, each node receives the BCC and transmits the SCH at the timing of the subslot at each timing.

In this way, the basic network can spread SCHs transmitted from a plurality of nodes.
That is, communication requests transmitted from slave nodes can be processed efficiently.

  Next, the operation of the entire communication system will be described.

  The second basic network 20 operates in the same manner as the first basic network 10 described above, and constructs the second basic network 20. That is, the communication system includes two basic networks constructed by the master node 100 and the master node 200.

  The relay nodes 120 and 220 receive the BCC transmitted from the master nodes 100 and 200, and also receive relay request information, relay communication data, and the like from the master nodes 100 and 200.

  When the relay node 120 receives the relay request information transmitted from the master node 100 via the BCC, the relay node 120 operates according to the information. The relay node 120 switches from communication in the basic network 10 to a communication state between the basic networks 10 and 20.

  Similarly, when the relay node 220 receives the relay request information transmitted from the master node 200 via the BCC, the relay node 220 switches to the basic inter-network communication state.

  The relay node 120 receives the BCC transmitted from the master node 100 using the first radio frequency F1 at the timing of the “M6” slot, and uses the second radio frequency F2 to transmit the BCC transmitted from the master node 200. Is received at the timing of the “M7” slot.

  When the relay node 120 makes a communication request to the master node 200, that is, when relaying communication, the relay node 120 determines the number of slots necessary for the sub-slot timing (SCH transmission timing) of “S2” or “S3”. A communication request including this is transmitted as an SCH. As shown in FIG. 4, the SCH transmitted here is a slot allocation frame that is 1/2 the length of other frames. That is, two SCHs can be transmitted in one time slot.

  Similarly to the relay node 120, the relay node 220 receives the BCC transmitted from the master node 200 using the second radio frequency F2, and uses the first radio frequency F1 to transmit the BCC transmitted from the master node 100. Receive.

  When the relay node 220 makes a communication request to the master node 100, that is, when relaying communication, the relay node 220 transmits the communication request as an SCH at the timing of the sub-slot of “S2” or “S3”.

  The relay nodes 120 and 220 relay communications by communicating communications transmitted from the master node to which the relay nodes 120 and 220 belong to a master node of another basic network. That is, the relay nodes 120 and 220 connect the first basic network 10 and the second basic network 20 and relay communication between the master nodes 100 and 200.

  In this way, the communication system can spread the SCH transmitted from the relay node.

  Further, the possibility that the relay node transmits a communication request simultaneously with other nodes can be reduced. Similarly, interference with communications other than communication requests can be reduced.

  That is, a communication request transmitted from the relay node can be processed efficiently.

  Next, another embodiment will be described.

  In the communication system, a slave node group transmits an SCH (communication request) using sub slots of “S2” and “S3” slots.

  When network information is transmitted and received between networks, it is necessary to generate a large amount of communication requests (SCH) in order to transmit and receive a large amount of traffic, and there is a probability that the communication request (SCH) of the relay node interferes. high. For this reason, a delay in communication speed and deterioration in communication efficiency occur due to the system load of the relay node and the concentration of communication.

  In the present embodiment, in addition to slot allocation information, a method in which a slave node group transmits a communication request, that is, information for specifying communication timing (used slot) as “S2” and “S3” slots, Communication request designation information for designating a communication method (slot usage method) such as instructing to use either the first half or the second half of. That is, the master node is characterized in that the communication request designation information is transmitted to the slave node group.

  The master nodes 100 and 200 allocate the timing for transmitting SCH preferentially to relay nodes and nodes that frequently communicate, and transmit communication request designation information using BCC.

  When the slave node 110 needs a slot, for example, when performing communication itself, the slave node 110 follows a communication request specifying information (SCH transmission timing, communication method) including a communication request including the necessary number of slots from the BCC. Transmit as SCH.

  This means that the slave node 110 transmits (transmits) the SCH according to the communication request designation information transmitted by the master node 100.

  Similar to the slave node 110, the relay node 120 receives the BCC and transmits the SCH according to the communication request designation information. Similarly, other slave nodes receive BCC and transmit SCH according to the communication request designation information.

  That is, the slave node group transmits a communication request according to the communication request specifying information specified by the master node.

  In this way, the communication system can spread the SCH transmitted from the relay node.

  Further, the possibility that the relay node transmits a communication request simultaneously with other nodes can be reduced. Similarly, interference with communications other than communication requests can be reduced.

  Further, since communication is concentrated in relay nodes and nodes that frequently communicate, congestion can be prevented by assigning a timing for preferentially transmitting SCH.

  Similarly, the probability that the SCH transmitted from the slave node group interferes with other SCHs and other communications is reduced, and the number of retransmissions is reduced, so that the processing load on each node can be reduced.

  Furthermore, congestion between networks that communicate at different frequencies can be prevented, and communication can be performed successfully.

  That is, it is possible to provide a wireless communication method that can efficiently process a communication request transmitted from a slave node group.

  Communication requests transmitted by relay nodes used for wireless communication between a plurality of networks can be efficiently processed.

  The timing for transmitting the SCH designated by the communication request designation information is not limited to the subslots of the “S2” and “S3” slots, but may be used in combination with other “S” slots. At this time, if the sub slots of the “S2” and “S3” slots are preferentially assigned, the communication efficiency can be improved.

  Similarly, if the relay node adjusts the transmission timing of communication using a built-in memory buffer, the communication efficiency between master nodes can be improved.

  The present invention can be applied to, for example, a radio communication system between a base station and a mobile station and a radio communication system between mobile stations.

10 first basic network 20 second basic network 100 first master node 110 slave node 120 first relay node 200 second master node 210 slave node 220 second relay node

Claims (13)

In a communication system in which a master node and a slave node group consisting of a plurality of slave nodes communicate through time slots assigned to each,
A specific time slot that is a part of the time slot assigned to the slave node group is divided into a plurality of sub time slots, and each slave node transmits a communication request using the sub time slot. By being received at the master node,
The wireless communication method, wherein the master node assigns a time slot from a time slot assigned to the slave node group to a slave node that has made the communication request. Claim 1 wherein
2. A radio communication method according to claim 1, wherein time slots assigned to the slave node group and divided into a plurality of sub time slots are a plurality of time slots. Claim 1 or 2,
The master node transmits communication request designation information for designating a slot or the like for transmitting a communication request to the slave node group,
A wireless communication method, wherein a slave node that transmits a communication request to the master node transmits a communication request according to the communication request designation information. In a network construction method in which a master node and a slave node group composed of a plurality of slave nodes communicate with each other via assigned time slots,
A specific time slot that is a part of the time slot assigned to the slave node group is divided into a plurality of sub time slots, and each slave node transmits a communication request using the sub time slot. By being received at the master node,
The master node enables communication by assigning a time slot from the time slot assigned to the slave node group to the slave node that has made the communication request,
A network construction method, wherein the master node and the slave node group construct a network. Claim 4 comprising:
The master node selects a relay node capable of communicating with another network from the slave node group,
The selected relay node transmits a communication request to a master node that configures another network using the sub time slot. Claim 4 or 5,
A network construction method characterized in that a time slot allocated to the slave node group and divided into a plurality of sub time slots is a plurality of time slots. Any one of claims 4 to 6,
The master node transmits communication request designation information for designating a slot or the like for transmitting a communication request to the slave node group,
A network construction method, wherein a slave node that transmits a communication request to the master node transmits a communication request according to the communication request designation information. It is claim 7, Comprising:
The master node allocates a slot for preferentially transmitting a communication request to the relay node, constructs the communication request designation information, and transmits the constructed communication request designation information Method. In a wireless communication system in which a master node and a slave node group composed of a plurality of slave nodes perform communication via assigned time slots,
The plurality of slave nodes use specific time slots of the allocated time slots as a plurality of sub time slots, and transmit communication request information using the sub time slots.
The wireless communication system, wherein the master node receives communication request information using the sub time slot. It is claim 9, Comprising:
The master node selects a relay node capable of communicating with another network from the slave node group,
The selected relay node transmits communication request information to a master node that constructs another network using the sub time slot. Claim 9 or 10, wherein
A wireless communication system, wherein time slots assigned to the slave node group and used as a plurality of sub time slots are a plurality of time slots. Any one of claims 9 to 11,
The master node transmits communication request designation information for designating a slot or the like for transmitting communication request information to the slave node group,
A wireless communication system, wherein a slave node that transmits a communication request to the master node transmits communication request information according to the communication request designation information. Claim 12.
The master node assigns a slot for preferentially transmitting communication request information to the relay node, constructs the communication request designation information, and transmits the constructed communication request designation information. Communications system.

Images