JP2012217091A - Radio communication device and radio communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method enabling stable communication even if the topology of a multi-hop network abruptly changes.SOLUTION: A radio communication device performs the steps of: acquiring identifier information of a base station to be connected; acquiring identifier information indicative of a source radio station of a received radio packet and a destination radio station thereof; determining whether any of the identifier information coincides with the identifier information of the base station or the identifier indicative of the device itself; determining whether retransmission relay is to be executed or completed in accordance with either one of a completion condition explicitly described in the radio packet and/or a completion condition of the retransmission relay determined on a system; and transmitting, if it is determined that one of the identifier information, indicative of the source radio station or the destination radio station, coincides with the identifier information of the base station and that the retransmission relay is to be executed, either of the received packet and a reconfigured packet that is obtained by modifying information described in a predetermined field in accordance with a predetermined condition.

Description

  The present invention relates to a wireless communication system in which a transmission source wireless station transmits and receives a wireless packet to and from a destination wireless station, and the distance between the transmission source wireless station and the destination wireless station is long or out of sight. The present invention relates to a wireless communication apparatus and a wireless communication method for performing stable wireless communication even in an environment including a case where direct wireless communication is difficult.

  In particular, when direct communication between the source radio station and the destination radio station becomes difficult, when a plurality of radio stations located around the source radio station and the destination radio station have successfully received radio packets. In addition, the present invention relates to a relay transmission technique for these radio stations to perform multi-hop relay cooperatively.

  In recent years, the spread of wireless communication has been remarkable. From mobile communications such as mobile phones, provision of spot wireless LAN services in quasi-stationary environments, provision of FWA (Fixed Wireless Access) services that provide wireless lines to homes as an alternative to wired lines such as optical fibers, etc. Services utilizing the advantages of wireless communication are being developed in various forms. At this time, from a business standpoint, it is desirable to cover a wide area with a small number of base station facilities and accommodate more user terminals. However, in general, the area area that can be covered by a single base station varies depending on conditions specific to the system (for example, frequency, transmission output, antenna gain, antenna installation location, modulation method, etc.) and propagation environment. For example, when a high-power transmission amplifier is provided as a function on the transmission side of a radio station, a wider area can be set as a service area. In general, a lower frequency is transmitted farther away.

  However, using a high-function, high-power transmission amplifier with high linearity will increase the price of the equipment, and there is also an upper limit on the transmission output according to regulations such as the Radio Law, so a transmission amplifier with too much power will be used. It is not desirable to expand the service area by using it. On the other hand, low frequency microwave bands are being used in many systems as easy-to-use frequency bands, so the frequency resources are already being depleted and it is expected that licenses will be allocated to new systems. Can not.

  As a result, when providing a service to a wide service area using a relatively high frequency band, the service area area obtained from the circuit design is often not sufficient from the viewpoint of business profitability. As a countermeasure in this case, it is conceivable to construct a wireless multi-hop network using many wireless stations in the area and perform relay transmission. As an example of such a multi-hop network, for example, a meshwork in a wireless LAN standard called IEEE802.11s is famous (see Non-Patent Document 1). Here, data arrives from a source radio station to a destination radio station. A routing method such as AODV has been proposed.

FIG. 15 shows an outline of routing in a wireless multi-hop network in the prior art.
In FIG. 15, reference numeral 100 denotes a network, 101 to 104 are wireless stations (specifically, 101 is a transmission source wireless station, 102 is a destination wireless station, and 103 to 104 are relay nodes). Represents a radio metric value. For example, when data is transferred from the network 100 to the wireless station 103, the wireless station 101 and the wireless station 103 can simply cope with each other by directly communicating via a wireless line. On the other hand, when data is transferred to the wireless station 102 that cannot directly communicate with the wireless station 101, the route of the transmission source wireless station 101 → the relay node 103 → the destination wireless station 102 and the transmission source wireless As in the route of the station 101 → the relay node 104 → the destination wireless station 102, a routing process for searching for an optimum route from routes having a plurality of options is required.

  In this routing process, first, a wireless metric defined as an index indicating the state of a wireless line such as a transmission speed, a traffic amount, and an interference amount that can be operated between wireless stations is used. In order to simplify the description, it is assumed here that the state of the wireless line is preferable when the wireless metric value is small. For example, in FIG. 15, the wireless metric value between the transmission source wireless station 101 and the relay node 103 is “12”, the wireless metric value between the transmission source wireless station 101 and the relay node 104 is “10”, and the relay node The radio metric value between 103 and the destination radio station 102 is “20”, and the radio metric value between the relay node 104 and the destination radio station 102 is “12”. Processing for performing routing under these conditions is shown below.

(Step 1) Each radio station exchanges radio metrics with neighboring radio stations.
(Step 2) The source wireless station 101 broadcasts a request packet in the multihop network. Specifically, a request packet containing a radio metric value is sent from the transmission source radio station 101 to neighboring relay nodes 103 to 104.

(Step 3) Each relay node 103 to 104 further adds a request packet obtained by adding (accumulating or adding) a radio metric value to the next radio station to the radio metric value in the received request packet. Send to. In FIG. 15, since both the relay node 103 and the relay node 104 have only the destination wireless station 102 as a relay destination, a request packet is transmitted to this station.

(Step 4) The destination radio station 102 refers to the radio metric value accommodated in the received request packet, and selects the one with the minimum radio metric value accumulated or added over the entire route. In FIG. 15, the route of the transmission source radio station 101 → the relay node 103 → the destination radio station 102 is the integrated (or addition) value of the radio metric values “12” and “20”, and the transmission source radio station 101 → the relay node as a route. Since the route of 104 → destination wireless station 102 is an integrated (or added) value of the radio metric values “10” and “12”, the route of the source wireless station 101 → relay node 104 → destination wireless station 102 is the route. It is judged preferable.

(Step 5) The destination wireless station 102 notifies the relay node of the route selected using the response packet. In FIG. 15, a response packet is sent to the relay node 104.

(Step 6) The relay node 104 that has received the response packet transfers the response packet to the previous wireless station on this route. Specifically, a response packet is transmitted to the transmission source radio station 101, and in the multi-hop network, the route of the transmission source radio station 101, the relay node 104, and the destination radio station 102 is selected and communication is determined.

  The above is an outline of routing in a multi-hop network. In general, when a large number of radio stations coexist, the number of logical routes becomes enormous, and it takes time to select an optimum route from among them. Therefore, in order to appropriately perform such routing processing, there is no change in the topology of the multi-hop network for a certain period, or the state of the individual link of each route is constant for a certain period and the change is small. This assumption is necessary.

FIG. 16 shows a configuration example of a conventional radio station apparatus.
In FIG. 16, 121 is a radio station apparatus, 122 is a radio unit, 123 is a baseband signal processing unit, 124 is a radio packet termination unit, 125 is an interface unit, 126 is an antenna, 127 is a communication control unit, and 128 is an identifier acquisition unit. Reference numeral 129 denotes an identifier match determination unit, 130 denotes a radio metric management unit, and 131 denotes the entire control unit. The radio station apparatus here is a general radio station apparatus including a base station and a terminal station, and the basic operation is as described below. In addition, if it is a base station, the function for managing the subordinate terminal station etc. will be added, For example, these functions can be seen as a part of function of the communication control part 127. FIG.

  The radio station apparatus 121 receives a signal via a radio line by an antenna 126, and performs filtering of an out-of-band signal by the radio unit 122, signal amplification by a low-noise amplifier, frequency conversion from an RF frequency to a baseband, and analog signal to digital Processing such as A / D conversion to a signal is performed. The digitized baseband signal is input to the baseband signal processing unit 123 and subjected to a series of baseband signal processing such as timing detection, termination of header information related to the physical layer, demodulation processing, and error correction. The specific processing content here depends on the radio system provided in the radio station apparatus, but the basic operation described below does not depend on the radio system.

  The demodulated signal output from the baseband signal processing unit 123 is input to the wireless packet termination unit 124, where the format of the packet communicated on the wired network such as Ethernet (registered trademark) from the wireless communication format. Is converted to This wireless packet includes overhead such as a so-called header area, and terminates various control information and error detection bits. For example, for a wireless packet determined to have no error by the error detection function, an identifier indicating a destination, a transmission source, or the like is extracted from the header information and transferred to the communication control unit 127. The communication control unit 127 manages the header information. The identifier acquisition unit 128 extracts the destination identifier from the header information, and the identifier match determination unit 129 determines match / mismatch with the own station identifier. This result is fed back to the communication control unit 127, and when it is determined that the destination is the local station, the communication control unit 127 instructs the wireless packet termination unit 124 to output data, and the format-converted packet The interface unit 125 adjusts electrical conditions and the like and outputs them to the outside.

Conversely, when a packet is input from the outside, it is input to the wireless packet termination unit 124 via the interface unit 125, where header information is added according to an instruction from the communication control unit 124, and further an error detection code, etc. Is added to generate a wireless packet. Here, in addition to the identifier of the destination wireless station, the identifier of the own station is given as the identifier of the transmission source. This signal is input to the baseband signal processing unit 123, where various modulation processes are performed in addition to the addition of header information related to the physical layer and the encoding for error correction, and the preamble signal is added to the base of the radio packet. Generate a band signal. This signal is input to the wireless unit 122, performs D / A conversion for converting a digital signal into an analog signal, frequency conversion, filtering of out-of-band signals, signal amplification, and the like, and is transmitted from the antenna 126.
When relaying a multi-hop network, it is determined whether or not to relay the received wireless packet based on the routing information set in advance by the communication control unit 127. The wireless packet terminating means 124 is notified of header information to be added to the wireless packet to be transmitted by the baseband signal processing unit 123 and the wireless unit 122 for predetermined signal processing on the wireless packet containing the new header information. The signal relayed from the antenna 126 is transmitted.

  When the above routing process is performed, the communication control unit 127 generates and terminates a request packet and a response packet, and manages a wireless metric value that is a communication state with surrounding wireless stations at that time. The necessary information is stored in a database through the wireless metric management means 130 for management.

  The series of signal processing described above is an overview of the entire process, and details include more detailed processing. For example, various timings such as management of a time division switch corresponding to switching between transmission and reception in the radio unit The communication control unit 127 performs control mainly from management to generation / termination of various control information. Further, here, the identifier acquisition unit 128, the identifier match determination unit 129, and the wireless metric management unit 130 have been described separately from the communication control unit 127, but it is also possible to regard all of these as one control unit 131. is there. In other words, it is not necessary to configure as a separate circuit different in hardware, and the entire control unit 131 exists as one circuit that performs software processing, and it is considered that logical functions are separated in its internal processing. It is possible.

Hidenori Aoki et al. “IEEE802.11s Wireless LAN Mesh Network Technology” NTT DoCoMo Technical Journal Vol.14 No.2 pp.14-pp.22, July 2006

The following problems exist in the multi-hop relay with the above routing.
(1) Since the routing processing of the prior art takes time from the start to the completion, frequent rerouting is necessary when the topology of each radio station that can be a relay node and the communication state of each link change rapidly. It becomes. This frequent rerouting overhead reduces communication efficiency.

  (2) Since the communication selected by routing is a combination of multiple stages of one-to-one communication, if an unstable ring exists somewhere on the path, the link is the communication characteristic of all paths. There is a risk of becoming a bottleneck that affects

  Regarding the above problem (1), for example, consider a multi-hop network composed of radio stations mounted in a large number of vehicles moving at high speed. In this case, each car is moving at a high speed, and in particular, in a network in which cars traveling in opposite directions are mixed, the topology changes rapidly. When a large number of vehicles can serve as relay nodes, it takes time to search for an optimum route when searching for various routes. For example, assume that routing takes about 1 second. If each car is moving at 60 km / h, the relative speed of cars traveling in opposite directions will be 120 km / h. Since the distance moved per second at this speed is about 33 m, the topology changes greatly with the movement of this distance. That is, the radio metric value obtained in the above (step 1) at the start of routing changes to a completely different value at the completion of routing, and if communication is continued for 1 second in that state, the accumulated car is about 67 m. It has moved. During this time, another car may enter the link where the line of sight should have been secured, and the line of sight may be interrupted. That is, the time required for routing must be small enough to be negligible with respect to the time scale in which the communication state is considered to be stable. However, this condition cannot be satisfied in the above-described wireless multi-hop network between automobiles.

  Regarding the above problem (2), consider a case where a base station connected to a network provides an FWA service to neighboring households. In this case, the base station has an antenna installed at a relatively high place, and it is highly likely that each user's home can be seen. However, since propagation attenuation with distance is inevitable, the reception level decreases as the distance increases, and as a result, the area where direct communication is possible is limited. Consider a case where an FWA terminal station in which a multi-hop network is set in the user's home is used as a relay node in such a state.

  Since each relay node is installed at a low place with respect to the base station, it is unlikely that a line of sight can be secured between the relay nodes. Furthermore, when there is an area where the density of radio stations that can locally become relay nodes is very low, the quality of communication between the relay nodes and the relay nodes deteriorates, and any of the selected routes If the link is unstable, the communication quality as a whole also becomes unstable. In the first place, the reason why such a problem occurs is that the conditions and installation environment of the base station and the general terminal station are asymmetric, and the communication between the base station and each terminal station is relatively good. However, communication between terminal stations is generally inferior in communication quality compared to communication with base stations, so if there is no element to compensate for the asymmetry, the efficiency of relaying in a multihop network Will decline.

  As described above, when the topology of the multi-hop network changes abruptly or when there is a non-target between the base station and the terminal station in the multi-hop network, the above (1), (2) New technology to solve this problem will be required.

  The present invention enables stable communication by suppressing the influence of the topology change even when the topology of the multi-hop network rapidly changes, and even when an unstable link exists somewhere on the route, An object of the present invention is to provide a wireless communication apparatus and a wireless communication method that enable stable communication while avoiding the risk that the unstable link becomes a bottleneck that affects the communication characteristics of all paths.

  The first invention is composed of one base station and a plurality of radio stations, and transmits and receives radio packets while performing direct or multi-hop relay between the base station and a radio station of a communication partner in the radio station. In the wireless communication device that performs, the wireless packet includes identifier information indicating the source wireless station and the destination wireless station, and the wireless station acquires identifier information of a base station to which the wireless station should connect via a wireless line. Base station identifier acquisition means, wireless packet reception means for receiving wireless packets, identifier acquisition means for acquiring identifier information indicating the source wireless station and destination wireless station of the received wireless packets, and transmission acquired by the identifier acquisition means An identifier match determination unit that determines whether any of the identifier information indicating the source wireless station or the destination wireless station matches the identifier information of the base station or the identifier indicating the own station. And retransmission execution judging means for judging whether or not to perform retransmission relay according to either the retransmission relay termination condition explicitly described in the wireless packet or the retransmission relay termination condition defined on the system And the identifier match determination means determines that either the identifier information indicating the source radio station or the destination radio station matches the identifier information of the base station, and the retransmission execution determination means determines that retransmission relay should be performed. A wireless packet transmitting means for transmitting either a wireless packet that has been received or transmitted as it is or after reconfiguring information described in a predetermined field according to a predetermined condition, and an identifier match determining means When it is determined that the identifier information indicating the destination wireless station matches the identifier information of the local station, the received wireless packet is terminated and data is received. And a wireless packet terminator withdrawing.

  In the wireless communication device of the first invention, the wireless packet includes control information including a retransmission counter value that is information relating to the number of retransmission relays in a predetermined field, and the retransmission execution determining means includes a predetermined field of the received wireless packet. A retransmission counter value acquisition means for acquiring the retransmission counter value described in the above, and a retransmission counter value match determination means for determining whether or not the retransmission counter value matches a predetermined condition. Retransmission counter updating means for adding or subtracting the retransmission counter value, and wireless packet updating means for reconstructing a wireless packet obtained by recording the updated retransmission counter value in a predetermined field.

  In the wireless communication apparatus of the first invention, the wireless station and the base station communicate using a commonly recognized time slot, and the retransmission execution determining means determines that the time slot in which the wireless packet is received is a predetermined periodic condition. If the time slot coincides with, it is determined that retransmission has ended.

  In the wireless communication apparatus of the first invention, the base station includes control information notification means for reporting control information related to whether or not to perform retransmission relay, and the wireless station acquires information notified from the control information notification means of the base station. A broadcast information acquisition unit configured to compare the information obtained by the broadcast information acquisition unit with a time slot in which a radio packet is to be transmitted and determine whether to perform retransmission relay or to terminate It is.

  The second invention is composed of one base station and a plurality of radio stations, and transmits and receives radio packets while performing direct or multi-hop relay between the base station and a radio station of a communication partner in the radio station. In the wireless communication method for performing wireless communication, the wireless packet includes identifier information indicating a transmission source wireless station and a destination wireless station, and the wireless station acquires identifier information of a base station to which the wireless station is to connect via a wireless line. A base station identifier acquisition step, a radio packet reception step for receiving a radio packet, an identifier acquisition step for acquiring identifier information indicating a transmission source radio station and a destination radio station of the received radio packet, and an acquired transmission source radio station or An identifier match determination step for determining whether any of the identifier information indicating the destination wireless station matches the identifier information of the base station or the identifier indicating the own station. And a retransmission execution determining step for determining whether or not to perform retransmission relay according to either the retransmission relay termination condition explicitly described in the wireless packet or the retransmission relay termination condition defined on the system And in the identifier match determination step, it is determined that either the identifier information indicating the transmission source radio station or the destination radio station matches the identifier information of the base station, and it is determined in the retransmission execution determination step that retransmission relay should be performed. In addition, the wireless packet transmission step for transmitting any of the received wireless packets as they are or by modifying the information described in the predetermined field according to the predetermined conditions and reconstructing the wireless packet, and the identifier wireless station in the identifier match determination step, When it is determined that the identifier information shown matches the identifier information of the local station, the wireless packet And a wireless packet terminal step of extracting the data terminates.

  In the wireless communication method of the second invention, the wireless packet includes control information including a retransmission counter value that is information related to the number of retransmission relays in a predetermined field, and the retransmission execution determining step includes a predetermined field of the received wireless packet. A retransmission counter value acquisition step for acquiring the retransmission counter value described in the above, and a retransmission counter value match determination step for determining whether or not the retransmission counter value matches a predetermined condition. A retransmission counter updating step of adding or subtracting the retransmission counter value, and a wireless packet updating step of reconstructing a wireless packet obtained by recording the updated retransmission counter value in a predetermined field.

  In the radio communication method according to the second invention, the radio station and the base station communicate using a commonly recognized time slot, and the retransmission execution determining step includes determining whether the time slot in which the radio packet is received has a predetermined periodic condition. It is determined that retransmission has ended when the time slot coincides with.

  In the radio communication method of the second invention, the base station performs a control information reporting step for reporting control information related to whether or not to perform retransmission relay, and the radio station transmits information notified from the control information reporting means of the base station. The broadcast information acquisition step to be acquired is performed, and the retransmission execution determination step compares the information obtained by the broadcast information acquisition means with the time slot in which the wireless packet is to be transmitted, and determines whether retransmission relay should be performed or not To do.

  The wireless communication apparatus and the wireless communication method of the present invention enable the transmission source wireless station and the destination wireless station to perform relay relay in multihop in a situation where it is difficult for the transmission source wireless station and the destination wireless station to directly perform data communication. When communication between stations is realized, it is possible to realize without requiring a routing process for optimizing a route in which one-to-one communication is combined in multiple stages. As a result, even when the topology of the multi-hop network changes abruptly, it becomes possible to provide stable communication while suppressing the influence of the topology change.

  Also, instead of combining one-to-one communication in multiple stages, a plurality of wireless stations are involved in retransmission relay, so even if there is an unstable ring somewhere on the route, many other Since routes are operated in parallel, it is possible to avoid the risk that unstable local links become a bottleneck that affects the communication characteristics of all routes.

It is a figure which shows the outline | summary of the basic operation | movement of the retransmission relay in this invention. It is a figure which shows the operation | movement outline | summary of the resending relay of Example 1 of this invention. It is a figure which shows the structural example of the radio station apparatus in Example 1 of this invention. It is a figure which shows the operation | movement flow of the retransmission relay in Example 1 of this invention. It is a figure which shows the operation | movement outline | summary of the resending relay of Example 2 of this invention. It is a figure which shows another operation | movement outline | summary of the resending relay of Example 2 of this invention. It is a figure which shows the operation | movement outline | summary of the resending relay of Example 3 of this invention. It is a figure which shows the structural example of the radio station apparatus in Example 3 of this invention. It is a figure which shows the operation | movement flow of the retransmission relay in Example 3 of this invention. It is a figure which shows the operation | movement outline | summary of the resending relay of Example 4 of this invention. It is a figure which shows the structural example of the radio station apparatus in Example 4 of this invention. It is a figure which shows the operation | movement flow of the retransmission relay in Example 4 of this invention. It is a figure which shows the operation | movement outline | summary of the resending relay of Example 5 of this invention. It is a figure which shows the operation | movement flow of the retransmission relay in Example 5 of this invention. It is a figure which shows the outline | summary of the routing in the conventional wireless multihop network. It is a figure which shows the structural example of the radio station apparatus in a prior art.

  Hereinafter, embodiments of a wireless communication apparatus of the present invention will be described in detail with reference to the drawings. First, the overall basic operation will be described before the description of the individual embodiments. In this specification, the term “retransmission relay” is used, but this is different from communication in which one-to-one communication at the time of multi-hop relay is combined in multiple stages, and the transmission source described in the header area It is intended to relay without rewriting the identifier of the destination wireless station, and does not mean so-called retransmission for error correction (ARQ: Automatic Repeat reQest).

FIG. 1 shows an outline of the basic operation of retransmission relay in the present invention.
In FIG. 1, 1-1 to 1-2 are base stations, 2-1 to 2-7 and 3-1 to 3-7 are radio stations, 4-1 to 4-2 are radio packets, 5-1 to 5 -2 represents the service area of each base station, and 100 represents a network.

  Base stations 1-1 and 1-2 connected to the network 100 form service areas 5-1 and 5-2, respectively. The service area 5-1 is an area managed by the base station 1-1, and the service area 5-2 is an area managed by the base station 1-2. Radio stations 2-1 to 2-7 exist in the service area 5-1, and radio stations 3-1 to 3-7 exist in the service area 5-2. The radio stations 2-1 to 2-3 can communicate with the base station 1-1, but the other radio stations 2-4 to 2-7 cannot directly communicate with the base station 1-1. The service area here refers to an area that is expanded as a multi-hop network by a radio station managed by the base station 1-1 and in which the radio station can communicate with the base station 1-1. Each of the base stations 1-1 to 1-2 and each of the wireless stations 2-1 to 3-7 is assigned an identifier. For example, the base station 1-1 has “A”, and the base station 1-2 has The identifier of “B”, “a” for the wireless station 2-1, “b” for the wireless station 2-2,..., “N” for the wireless station 3-7.

  Assume that the radio stations 2-1 to 3-7 belonging to each service area 5-1 to 5-2 know the identifier of the base station that manages the service area. This grasping method may be any method. For example, in the case of an FWA service, base station information for each service area may be set at the time of service contract. If the position of the wireless station is known, it is provided on the network or the wireless station. The identifier of the base station may be grasped by referring to the database and the position information. Furthermore, the base station may notify the users in the area. In this way, for example, the wireless station 2-1 in the service area 5-1 recognizes in advance that the identifier of the base station 1-1 that manages its own station is “A”.

  Next, consider a case where there is data to be transmitted from the network 100 to the radio station 2-7. This data is input from the network 100 to the base station 1-1, and the base station 1-1 generates a radio packet 4-1 that includes a sender identifier “A” and a destination identifier “g” in the header area. Send this. This signal is received by the radio stations 2-1 to 2-3 in the vicinity of the base station 1-1. For example, when the wireless station 2-1 receives the wireless packet 4-1, the wireless station 2-1 recognizes the transmission source identifier “A” and the destination identifier “g” as identifiers assigned to the header area. Here, since the identifier of the base station 1-1 that manages the own station is “A”, it can be recognized that the transmission source is the base station 1-1 that manages the own station. The wireless stations 2-1 to 2-3 that have received the wireless packet 4-1 under such conditions retransmit the signal, and the relayed signal can be received by the wireless stations 2-4 to 2-6. . Similarly, these wireless stations 2-4 to 2-6 receive a wireless packet equivalent to the wireless packet 4-1, and the identifier “A” of the transmission source and the identifier “destination” “ g ”is recognized.

  Here, since the identifier of the base station 1-1 that manages the wireless station 2-4 to 2-6 is "A", the transmission source is the base station 1-1 that manages the local station. Can be recognized. Similarly, the signal is retransmitted and the relayed signal is received by the radio station 2-7. The radio station 2-7 recognizes the identifier “A” of the transmission source and the identifier “g” of the destination as identifiers given to the header area of the received radio packet, and the destination identifier matches the identifier of the own station. Recognize As a result, it is possible to recognize that this wireless packet is addressed to the own station, terminate this wireless packet, and take out the data contained therein. In this way, communication from the base station 1-1 to the radio station 2-7 is realized.

  Next, uplink communication from the downstream to the upstream of the multihop network will be described. For example, consider a case where there is data to be transmitted from the wireless station 3-7 to the network 100 side. The radio station 3-7 generates a radio packet 4-2 including a transmission source identifier “n” and a destination identifier “B” in the header area, and transmits this. This signal is received by radio stations 3-4 to 3-6 in the vicinity of the radio station 3-7. For example, when receiving the wireless packet 4-2, the wireless station 3-4 recognizes the transmission source identifier “n” and the destination identifier “B” as identifiers assigned to the header area. Here, since the identifier of the base station 1-2 that manages the own station is “B”, it can be recognized that the destination is the base station 1-2 that manages the own station. The radio stations 3-4 to 3-6 that have received the radio packet 4-2 under such conditions retransmit the signal, and the radio stations 3-1 to 3-3 have received the relayed signal. To do. Similarly, these wireless stations 3-1 to 3-3 receive a wireless packet equivalent to the wireless packet 4-2, and the identifier “n” of the transmission source and the identifier “destination” “ B ”is recognized.

  Here, since the identifier of the base station 1-2 that manages its own station is “B”, the wireless stations 3-1 to 3-3 also recognize that the destination is the base station 1-2 that manages its own station. can do. Similarly, the signal is relayed again, and the base station 1-2 receives the relayed signal. The base station 1-2 recognizes the identifier “n” of the transmission source and the identifier “B” of the destination as identifiers given to the header area of the received wireless packet, and the destination identifier matches the identifier of the own station. Recognize As a result, it is possible to recognize that this wireless packet is addressed to the own station, terminate this wireless packet, take out the data accommodated therein, and transfer it to the network 100. In this way, communication from the radio station 3-7 to the base station 1-2 is realized.

  It should be noted here that, for example, a signal equivalent to the wireless packet 4-2 retransmitted by the wireless station 3-4 due to leakage of radio waves from a nearby service area is transmitted to the base station 1-1. It is assumed that, for example, the radio station 2-3 or the radio station 2-6 (which means that the radio station 2-3 exists in the service area 5-1 of the base station 1-1) has been received. At this time, the wireless station 2-3 or 2-6 can recognize the identifier “n” of the transmission source and the identifier “B” of the destination as identifiers given to the header area of the received wireless packet. Since neither of them matches the identifier “A” of the base station 1-1 that manages the own station, retransmission relay is not performed.

  The above is the basic operation of the present invention. Here, a feature of the present invention is that there are a plurality of wireless stations that perform relay, and all of them transmit signals having the same content at the same frequency and at the same timing. When the frequency error of each radio station can be ignored, even if there is a slight timing error, it can be regarded as a signal equivalent to a multipath signal. In addition, in FIG. 1, since three radio stations transmit at the same time, the total transmission power is tripled, and a diversity effect is also obtained because the signals are from physically different places. On the receiving side, signals from multiple radio stations are combined and received, so it is expected that the characteristics will vary from radio station to radio station, but the gain is improved by the number of relay stations with respect to the average received power. Therefore, it is expected that the line gain of the entire system is greatly improved. In particular, even if there is a locally unrecognizable link, signals can be received from a plurality of radio stations, and a plurality of candidates exist on the receiving side, so the diversity effect is very large. Furthermore, since the one-to-one communication is not configured in multiple stages, a routing process for selecting an optimum route is unnecessary, and it is possible to flexibly cope with a sudden change in topology.

  Hereinafter, a specific embodiment for realizing multi-hop retransmission relay according to the present invention will be described.

Example 1
FIG. 2 shows an outline of the operation of retransmission relay according to the first embodiment of the present invention.
In FIG. 2, 11 is a base station, 12-1 to 12-9 are radio stations that perform retransmission relay, and 13 is a destination radio station. 2 (1) shows the positional relationship between the base station 11, the radio stations 12-1 to 12-9, and the destination radio station 13, and FIG. 2 (2) shows the transmission or transmission of each radio station in the time slots # 1 to # 8. The reception state is shown, and the horizontal axis indicates time.

  When the base station 11 transmits a wireless packet in time slot # 1, the wireless stations 12-1 to 12-3 receive this signal. In the next time slot # 2, the base station 11 transmitting in the previous time slot # 1 and the receiving radio stations 12-1 to 12-3 perform transmission operation, and this signal is transmitted to the radio station 12- 4-12-6 receive. In the next time slot # 3, the base station 11 and the radio stations 12-1 to 12-3 that have been transmitting in the previous time slot # 2 and the radio stations 12-4 to 12-6 that have received the transmission operation The radio stations 12-7 to 12-9 receive this signal. In the next time slot # 4, the base station 11 and the radio stations 12-1 to 12-6 that have been transmitting in the previous time slot # 3 and the radio stations 12-7 to 12-9 that have received the transmission operation The destination wireless station 13 receives this signal. Thereby, the destination wireless station 13 can receive the wireless packet transmitted by the base station 11.

  Similarly, when the wireless station 13 transmits a wireless packet to the base station 11, when the wireless station 13 transmits a wireless packet in time slot # 5, the wireless stations 12-7 to 12-9 receive this signal. In the next time slot # 6, the radio station 13 that was transmitting in the previous time slot # 5 and the radio stations 12-7 to 12-9 that were receiving perform transmission operations, and this signal is transmitted to the radio station 12- 4-12-6 receive. In the next time slot # 7, the radio station 13 and radio stations 12-7 to 12-9 that were transmitting in the previous time slot # 6 and the radio stations 12-4 to 12-6 that have received the transmission operation The radio stations 12-1 to 12-3 receive this signal. In the next time slot # 8, the radio station 13 and radio stations 12-4 to 12-9 that were transmitting in the previous time slot # 7 and the radio stations 12-1 to 12-3 that have received the transmission operation The base station 11 receives this signal. Thereby, the base station 11 can receive the radio packet transmitted by the radio station 13.

  The feature of the first embodiment is that the received radio packet is repeatedly transmitted repeatedly until a predetermined time slot. In this manner, the final radio packet delivery can be ensured by increasing the total transmission power. Here, with regard to which time slot is repeatedly transmitted (that is, the upper limit of the number of retransmission relays), for example, the radius of the service area and the statistical level regarding how far the wireless packet reaches by one retransmission relay If the information is estimated from the circuit design, it is possible to estimate how many retransmission relays can cover the service area. In the following embodiment, an information sharing method between the base station 11 and subordinate radio stations (12-1 to 12-9 and 13) relating to information on which time slot to repeat retransmission relay is concretely described. However, it is assumed that the setting of the upper limit value of the number of retransmission relays is obtained from the above-described line design information.

FIG. 3 shows a configuration example of a radio station apparatus according to Embodiment 1 of the present invention.
In FIG. 3, 21 is a radio station device, 22 is a radio unit, 23 is a baseband signal processing unit, 24 is a radio packet termination unit, 25 is an interface unit, 26 is an antenna, 27 is a communication control unit, and 28 is an identifier acquisition unit. , 29 is an identifier match determination unit, 30 is a base station identifier acquisition unit, 31 is a retransmission relay execution determination unit, and 32 is an entire control unit. As described in the description of the prior art, the wireless station device here is a general wireless station device including a base station and a terminal station. If it is a base station, a function for managing a terminal station under its control, etc. However, since these functions can be regarded as a part of the functions of the communication control unit 27, it is basically possible to understand including the base station and the terminal station in the following description. .

  The basic operation is the same as that of the prior art, but the operation in the case of retransmitting a packet other than the wireless packet addressed to itself is different in the present invention. Therefore, only this point will be described here. A signal via a wireless line is received by the antenna 26, and the signal processed by the wireless unit 22 and the baseband signal processing unit 23 is input to the wireless packet terminator 24. Is converted to a typical packet format. Here, an identifier indicating a destination, a transmission source, and the like is extracted from the header information attached to the wireless packet, and is transferred to the communication control unit 27. The communication control unit 27 manages the header information. The identifier acquisition unit 28 extracts the source and destination identifiers from the header information, and the identifier match determination unit 29 connects the local station identifier and the local station to which the local station is connected. A match / mismatch determination with the identifier is performed. This result is fed back to the communication control unit 27. When it is determined that the destination is the local station, the communication control unit instructs the wireless packet termination unit 24 to output data, and the format-converted packet is transmitted. The interface unit 25 adjusts electrical conditions and the like and outputs the result to the outside.

  On the other hand, when the identifier match determination means 29 determines that the identifier of the base station to which the own station is connected but not to the own station matches the destination or the transmission source, this result is notified to the retransmission relay execution determination means 31. The retransmission relay execution determining means 31 determines whether or not the retransmission relay can be performed in consideration of various determination conditions described later, and notifies the communication control unit 27 of the result. When the communication control unit 27 receives an instruction to perform retransmission relay, the wireless packet termination unit 24 receives the wireless packet as it is or changes the header information according to a predetermined rule, and performs processing such as error detection coding. The wireless packet is updated, and this is transmitted to the wireless line via the baseband signal processing unit 23, the wireless unit 22, and the antenna 26. In this way, retransmission relay is performed.

  In addition, although the change rule of the header information of a radio | wireless packet, the judgment conditions of retransmission relay implementation judgment, etc. are demonstrated in the following examples, it is not limited to these examples. Also, the base station identifier acquisition means 30 is a base station to which the own station is to be connected when the communication control unit 27 acquires the base station identifier notified by the base station or from various information provided by itself. Get identifier information. That is, the identifier of the base station may be acquired from a radio packet received from the base station, or may be referred to from a database held by the own station. In this case, if the wireless station can acquire the position information of its own station such as GPS, an identifier corresponding to the nearest base station is acquired based on the position information and the position of the base station on the database, etc. It is also possible to acquire based on other information. In the case of an FWA service or the like, it may be set at the time of contracting or at the time of equipment installation. As described above, the purpose of “acquisition of identifier” by the base station identifier acquisition means 30 is not necessarily active acquisition, but is processing of reading setting values in the apparatus and searching from a database. Also good. Thus, the base station identifier acquisition means 30 manages the identifier information acquired in various forms, and responds to the inquiry of the identifier match determination means 29. The communication control unit 27, the identifier acquisition unit 28, the identifier match determination unit 29, the base station identifier acquisition unit 30, and the retransmission relay execution determination unit 31 have been described separately from the communication control unit 27. It can also be regarded as the entire control unit 32 of the above. That is, it is not necessary to configure as a separate circuit different in hardware, and the entire control unit 32 exists as one circuit that performs software processing, and the logical functions are considered to be separated in its internal processing. It is also possible.

  The above is the operation when a wireless packet is received through a wireless line, but when a packet is input from the outside, naturally the reference such as the identifier is omitted and the transmission operation similar to the conventional technique is performed. . However, in the prior art, an operation for routing is defined, but in the present invention, since wireless packets are transferred without performing routing, these functions are not necessary.

  The series of signal processing described above is an overview of the entire process, and details include more detailed processing. For example, various timings such as management of a time division switch corresponding to switching between transmission and reception in the radio unit The communication control unit 27 performs control mainly from management to generation / termination of various control information.

FIG. 4 shows an operation flow of retransmission relay in Embodiment 1 of the present invention.
In the figure, when each wireless station receives a wireless packet (S1), it obtains the identifier of the wireless station that is the transmission source and the destination from a predetermined field of the received wireless packet (S2), and the destination identifier is the identifier of its own station. It is determined whether or not (S3). If they match, the wireless packet is terminated and data output processing is performed (S6), and the processing is terminated as "no retransmission relay" (S7).

  On the other hand, if they do not match in step S3, it is determined whether or not the source or destination identifier matches the identifier of the base station that manages the local station (S4). And the process is terminated (S7). On the other hand, if they match, it is determined whether or not the retransmission relay execution conditions are met (S5). If the retransmission execution conditions are met, retransmission relay is performed (S9). End (S8). When retransmission relay is performed in step S9, the process returns to step S5 again after the retransmission relay is performed, and it is continuously determined whether or not the conditions for retransmission relay are met. If the repeated retransmission execution condition is met, the retransmission relay is continued a plurality of times, and the retransmission relay is terminated when the condition is not met. Note that the retransmission relay execution condition here is a specific example in the following embodiment. For example, to what time slot the retransmission relay is continued, how many times the retransmission relay is performed, and the retransmission relay is terminated. It means conditions such as.

The above description does not involve any routing processing as described in the prior art. When a base station or terminal station is a transmitting station, it is necessary to ensure consistency such as setting header information of radio packets as needed or adapting frame conditions and broadcast information to retransmission relay conditions as necessary. There is. Further, after the new transmission of the wireless packet (S10), the transmitting station proceeds to the process S5 in the same manner as when receiving the wireless packet, and the subsequent processing is the same as when receiving the wireless packet and matches the retransmission execution condition. Whether or not retransmission relay is completed (S8) or retransmission relay execution (S9) is executed according to the determination result.
(Example 2)

  FIG. 5 shows an operation outline of retransmission relay according to the second embodiment of the present invention. The difference from the first embodiment shown in FIG. 2 is that the radio station that performs retransmission relay is different.

  In FIG. 5, when the base station 11 transmits a radio packet in time slot # 1, the radio stations 12-1 to 12-3 receive this signal. In the next time slot # 2, the base station 11 does not transmit, and the radio stations 12-1 to 12-3 received in the previous time slot # 1 perform the transmission operation, and this signal is transmitted to the radio station 12- 4-12-6 receive. In the next time slot # 3, the base station 11 and the radio stations 12-1 to 12-3 do not transmit, and the radio stations 12-4 to 12-6 received in the previous time slot # 2 perform transmission operation. The radio stations 12-7 to 12-9 receive this signal. In the next time slot # 4, the base station 11 and the radio stations 12-1 to 12-6 do not transmit, and the radio stations 12-7 to 12-9 received in the previous time slot # 3 perform the transmission operation. The destination wireless station 13 receives this signal. Thereby, the destination wireless station 13 can receive the wireless packet transmitted by the base station 11.

  Similarly, when the wireless station 13 transmits a wireless packet to the base station 11, when the wireless station 13 transmits a wireless packet in time slot # 5, the wireless stations 12-7 to 12-9 receive this signal. In the next time slot # 6, the radio station 13 does not transmit, and the radio stations 12-7 to 12-9 received in the previous time slot # 5 perform the transmission operation, and this signal is transmitted to the radio station 12- 4-12-6 receive. In the next time slot # 7, the radio station 13 and the radio stations 12-7 to 12-9 do not transmit, and the radio stations 12-4 to 12-6 received in the previous time slot # 6 perform the transmission operation. The radio stations 12-1 to 12-3 receive this signal. In the next time slot # 8, the radio station 13 and the radio stations 12-4 to 12-9 do not transmit, and the radio stations 12-1 to 12-3 received in the previous time slot # 7 perform the transmission operation. The base station 11 receives this signal. Thereby, the base station 11 can receive the radio packet transmitted by the radio station 13.

  A feature of the present embodiment is that a wireless station that has received a wireless packet performs retransmission relay only in the next time slot. In this way, by suppressing the transmission of a radio station that is considered to be less effective even if it is retransmitted too much, it is possible to reduce interference with surrounding service areas compared to the first embodiment. Note that the number of retransmissions is not necessarily limited to one and may be limited. For example, FIG. 6 shows an outline of the operation when retransmission relay is performed twice, which corresponds to the intermediate operation shown in FIG. 2 and FIG.

The operation flow of retransmission relay in the second embodiment of the present invention is basically the same as the processing shown in FIG. 4. In the case of the contents shown in FIG. 5, the first retransmission relay is performed in step S5 of FIG. In the case of the contents shown in FIG. 6, it is determined in the process S5 of FIG.
Here, for example, it is assumed that the signals transmitted in time slot # 3 are actually received by radio stations 12-1 to 12-3 and base station 11. However, as in the embodiment shown below, if it is possible to grasp to which time slot a series of retransmission relays continues, the wireless packet received in time slot # 3 is transmitted to the wireless stations 12-1 to 12-1. 12-3 and the base station 11 can recognize that the retransmission relay is already completed, and in this case, in step S5 of FIG. 4, it is determined that the retransmission relay execution condition is not met. Become. The same recognition is performed, for example, by assigning a serial number or the like to the wireless packet and determining that it is the same as the wireless packet for which retransmission has been completed. Similarly, in the process S5 in FIG. It is also possible.

(Example 3)
FIG. 7 shows an operation outline of retransmission relay according to the third embodiment of the present invention. The difference from the first embodiment shown in FIG. 2 is that the upper limit of the number of retransmission relays is managed using a retransmission counter.

  In FIG. 7, when the base station 11 transmits a radio packet addressed to the radio station 13, in addition to the identifier of the transmission source radio station and the destination radio station in the header area, the upper limit value of the number of retransmission relays is set as the retransmission counter value RC. The accommodated radio packet is configured and transmitted.

  The radio stations 12-1 to 12-3 that have received the radio packet transmitted by the base station 11 in the time slot # 1 store the identifiers of the source radio station and the destination radio station contained in the radio packet, and the retransmission counter value RC. If any of the identifiers of the source radio station and the destination radio station matches the identifier of the base station 11 that manages the own station, the retransmission counter value RC is decremented by 1 and transmitted in time slot # 2. At this time, the base station 11 that performed transmission in the previous time slot # 1 also decrements the retransmission counter value RC added to the transmitted radio packet by 1, and transmits in time slot # 2.

  Similarly, the radio stations 12-4 to 12-6 that have received the radio packet in the time slot # 2 refer to the identifiers of the transmission source radio station and the destination radio station accommodated in the radio packet and the retransmission counter value RC, If any of the identifiers of the source radio station and the destination radio station matches the identifier of the base station 11 that manages the own station, the retransmission counter value RC is decremented by 1 and transmitted in time slot # 3. At this time, the base station 11 and the radio stations 12-1 to 12-3 that have transmitted in the previous time slot # 2 also subtract the retransmission counter value RC added to the transmitted radio packet by 1, and the time slot Send in # 3.

  By repeating the above processing, the retransmission counter value RC is 3 in time slot # 1, the retransmission counter value RC is 2 in time slot # 2, the retransmission counter value RC is 1 in time slot # 3, and the retransmission counter value in time slot # 4. RC becomes 0, and the base station 11 and the radio stations 12-1 to 12-9 and the destination radio station 13 that have received or transmitted the radio packet in the time slot # 4 recognize that further retransmission relay is unnecessary, Complete retransmission relay. The destination wireless station 13 receives the wireless packet in this time slot # 4, and the transfer of the wireless packet from the base station 11 to the destination wireless station 13 is completed.

  Similarly, a case where the base station 11 transmits a wireless packet to the wireless station 12-7 will be described. When the radio station 12-7 is located at a shorter distance than the radio station 13, the base station 11 appropriately sets the retransmission counter value RC according to the distance or the location where the destination radio station 12-7 exists. In this figure, the retransmission counter value RC is set to 2. Similarly to the above description, the wireless packets are sequentially retransmitted, but in time slot # 7, the base station 11 and the wireless stations 12-1 to 12-6 that transmitted the wireless packet, and the wireless station 12 that received the wireless packet. In -7 to 12-9, since the retransmission counter value RC accommodated in the wireless packet is 0, the retransmission relay ends. Therefore, transmission / reception is not performed if there is no radio packet to be transmitted in time slot # 8.

  Similarly, when a wireless packet is retransmitted from the wireless station side to the base station side, the wireless station serving as a transmission source sets the retransmission counter value RC to the wireless packet as appropriate and transmits it.

  As a method of setting a retransmission counter value RC by a base station that transmits a radio packet to a destination radio station, if a rough position where the destination radio station exists is known, a distance of one hop is transferred. It is possible to estimate whether it is possible in consideration of the propagation environment, and to determine how many times repeat transmission is performed. Also, in a wireless station that transmits a wireless packet to a base station, it is possible to determine how many times retransmission is repeated from the relationship between the location of the own station and the location of the base station.

Furthermore, if the initial value of the retransmission counter value is accommodated in addition to the retransmission counter value RC in the header area of the wireless packet transmitted by the base station 11, each wireless station can determine what wireless packet is addressed to itself. It is possible to know whether it has been reached by the second retransmission, and it is also possible to estimate the number of hops necessary for transmission in the reverse direction based on this information. In the same control, the initial value of the retransmission counter value is set to 0 and the final value of the retransmission counter value is accommodated together, and the retransmission counter value is incremented by 1 for each retransmission relay. In the case where it matches the final value of the counter value, the process for determining the end of retransmission relay is also effectively equivalent.
Note that the number of hops is not necessarily symmetrical between the downlink direction from the base station to the terminal station and the uplink direction from the terminal station to the base station. This easily occurs when the transmission power of a base station and a general wireless station are different, and therefore the uplink / downlink retransmission counter value may be optimized in consideration of this point. The simplest method is to add a fixed number of hops (for example, plus one) to the number of hops required in the downlink direction. Different values may be used under individual conditions in consideration of the transmission power of the radio station, antenna gain, and the like.
Further, in the present embodiment, a case has been shown in which all the wireless stations repeatedly perform retransmission relay until the retransmission counter value RC becomes zero. However, as illustrated in the second embodiment, when retransmission retransmission is performed several times. Thereafter, regardless of the value of the retransmission counter value, the operation of not performing retransmission relaying may be performed.

  FIG. 8 shows a configuration example of a radio station apparatus according to the third embodiment of the present invention. The difference from the configuration example of the wireless station apparatus according to the first embodiment illustrated in FIG. 3 is that a retransmission counter acquisition unit 33 and a retransmission counter match determination unit 34 are added.

  In operation, when a wireless packet is received via a wireless line, information on the retransmission counter value is also transmitted from the wireless packet terminating means 24 from the header area of the wireless packet in addition to the identifier of the destination and transmission source wireless station. 27, and the retransmission counter value is transferred from the communication control unit 27 to the retransmission counter acquisition means 33. In the retransmission counter acquisition unit 33, the retransmission counter match determination unit 34 checks whether a predetermined value (for example, zero when the count value is subtracted by 1 as shown in FIG. 7) and the retransmission counter value match. The result is notified to retransmission relay execution determination means 31, and whether or not retransmission relay is possible is determined together with the result notified from identifier match determination means 29, the result is notified to communication control unit 27, and retransmission relay is performed according to the instruction. To implement. Here, the setting of the retransmission counter value to be newly transmitted or relayed for retransmission is performed by the communication control unit 27, and the value is reflected in the wireless packet by the wireless packet terminating unit 24.

  FIG. 9 shows an operation flow of retransmission relay according to the third embodiment of the present invention. The basic operation is the same as that of the first embodiment shown in FIG. 4, but here, the process using the retransmission counter value is performed to determine whether or not the retransmission execution condition in the process S5 of FIG. 4 is met. For this reason, the process S2 in FIG. 4 is replaced with a process (S11) for simultaneously acquiring a retransmission counter value. Further, in step S5 of FIG. 4, which is a retransmission execution determination, it is determined whether the retransmission counter value RC is 0 (S12). If it is 0, retransmission relay is terminated (S8). If it is other than 0 in the process S12, the retransmission counter value RC is decremented by 1 (S13), the radio packet containing the subtracted retransmission counter value RC is reconstructed (S14), and the retransmission relay of this radio packet is performed. Implement (S9).

  As in the case of FIG. 4, after the process S9 is performed, the process returns to the process S12 for determining whether to perform the next retransmission, and the retransmission is repeated a predetermined number of times. The same applies to the time of new transmission of a wireless packet (S10). After the completion of the new transmission process, the process proceeds to process S12 corresponding to process S5 in FIG. 4, and the same process is repeated. When a new wireless packet is transmitted, processing for setting a retransmission counter to a predetermined value is performed in addition to normal transmission processing. In the example of FIG. 9, since the retransmission counter value RC is a value indicating the remaining number of retransmissions, the counter value is subtracted by 1 for each retransmission, but the same processing is performed under different conditions. Is possible. For example, when the upper limit value of the number of retransmissions is set, the retransmission counter value RC is incremented by 1 in the process S13 for each retransmission, and in the process S12 whether or not the retransmission counter matches the upper limit of the number of retransmissions. You may judge. Further, if the retransmission counter is represented by a binary number and each bit indicates whether or not the first, second,... Retransmission is performed, the processing can be performed by inverting the corresponding bit. is there. As described above, any specific implementation method of the retransmission counter may be used as long as it can determine whether to perform retransmission and the number of remaining retransmissions.

Example 4
FIG. 10 shows an operation outline of retransmission relay according to the fourth embodiment of the present invention. The difference from the third embodiment shown in FIG. 7 is that the upper limit of the number of retransmissions is managed without using the retransmission counter value here.

  In FIG. 10, time slots # 1 to # 4 have a first frame, and time slots # 5 to # 8 have a second frame. Each retransmission relay is completed in units of frames, and no retransmission relay is performed across frames. The retransmission relay from time slot # 1 to time slot # 4 is exactly the same as the operation of the first embodiment shown in FIG. 2, except that in time slot # 4, base station 11 and radio stations 12-1 to 12- 9 and the destination wireless station 13 recognize that it is the last time slot of the first frame, and cancel further retransmission relay.

  In FIG. 2, transfer of a wireless packet from the base station 11 to the destination wireless station 13 has been described, but here, transfer of a wireless packet addressed to the wireless station 12-4 will be described. Since the wireless station 12-4 is relatively close to the base station 11, it can sufficiently receive wireless packets up to time slot # 6. However, when a common frame length is used for each frame, retransmission relay is not terminated at this time slot # 6. As a result, when the wireless station 12-4 as the destination has successfully received the wireless packet by time slot # 6, retransmission relay is continued in time slot # 7 and time slot # 8. .

  Here, the frame period takes into account the service area supported by each base station, estimates the number of retransmission relays required to deliver a wireless packet to the end of the service area, and sets the number of time slots according to this value as the frame length. Set. Alternatively, the frame length may be fixedly given as a system-specific value when the system is installed. Note that the frame length is not necessarily given in real time. Specifically, since the data length of each wireless packet to be transmitted is not necessarily constant, the time required for transmitting each wireless packet is not constant. In this case, the time required for transmission of the wireless packet given by the data length of the wireless packet and the modulation method and the time of the gap between the wireless packet and the wireless packet in the guard time are set as the unit time slot length for each wireless packet. The frame length may be defined as many as the unit time slot length. Furthermore, in addition to determining this frame length under a fixed condition, a method may be adopted in which the frame length is determined while being dynamically changed in the control information broadcast from the base station.

  Note that the functional block configuration in the present embodiment is basically the same as that in the first embodiment shown in FIG. 3, but in this case, the communication control unit 27 has a function of managing the frame period. Become. This frame period may be synchronized according to information notified from the base station apparatus, and as shown in FIG. 11, synchronization is achieved based on information on timing obtained from another wireless system such as a GPS 35. It doesn't matter. In the case of using GPS, each radio station can share a highly accurate absolute time, so that each time slot break (frame break) can be easily grasped. Further, the other wireless system may be a radio clock, for example. Any device that can grasp time information necessary for such synchronization can be used.

  FIG. 12 shows an operation flow of retransmission relay according to the fourth embodiment of the present invention. The basic operation is the same as that of the first embodiment shown in FIG. 4, but here, the process using the frame condition is used to determine whether or not the retransmission execution condition in the process S5 of FIG. 4 is met. For this reason, in the process S5 of FIG. 4 which is a retransmission execution determination, first, the frame condition is grasped (S15), it is determined whether or not it is a frame END (S16), and in the case of the frame END, the retransmission relay is terminated ( S8). On the other hand, in cases other than the frame END, retransmission relay is performed (S9). As in the case of FIG. 4, after the process S9 is performed, the process returns to the process S15, and retransmission is repeated a predetermined number of times until the frame END is reached. The same applies to the time of new transmission of a wireless packet (S10). After the completion of the new transmission process, the process proceeds to processes S15 and S16 corresponding to process S5 in FIG. 4, and the same process is repeated. When a new wireless packet is transmitted, transmission starts from the beginning of the frame.

(Example 5)
In addition to the above description, retransmission information can be determined by using information broadcast from the base station.

FIG. 13 shows an operation outline of retransmission relay according to the fifth embodiment of the present invention.
In FIG. 13, 19 is broadcast information from the base station. Whether or not the retransmission relay can be performed is well-known for each of the time slots # 1 to # 8 for performing the retransmission relay of the wireless packet. If there is an instruction that there is retransmission, retransmission is performed, and if there is no instruction for retransmission, retransmission is not performed. For example, in time slots # 1 to # 3 and time slots # 5 to # 7, since there is a retransmission instruction from the base station, retransmission relay is performed in the next time slot. Since there is no retransmission instruction from the station, retransmission relay is not performed in the next time slot. This retransmission instruction may explicitly indicate that retransmission is performed, or may be performed if there is no explicit instruction to cancel retransmission.
Alternatively, one retransmission instruction may mean multiple retransmissions thereafter. In this case, even if there is no retransmission instruction, if an instruction is given in the immediately preceding time slot, it is possible to perform retransmission. In this case, on the contrary, when resending is canceled, it is necessary to cancel the resending instruction from the previous time slot. Specifically, if a single “with retransmission” instruction indicates two retransmission relays, in order to instruct the completion of retransmission relay in time slot # 4, The instruction “with retransmission” should be the last, and the instruction “with retransmission” should not be given in time slot # 3.

  Further, this retransmission instruction may be transmitted in the gap between the transmission timings of the respective wireless packets, or such a signal may be accommodated in a specific subcarrier using OFDMA or the like. Furthermore, in order to secure the line gain, a fixed signal with a known pattern is transmitted, and the reception side performs correlation detection of the signal, and if a signal with a correlation value equal to or higher than a predetermined level is detected, retransmission is performed. It can also be determined as an instruction. In other words, the retransmission instruction may be given under any conditions including cases where the transmission method is different.

  FIG. 14 shows an operation flow of retransmission relay according to the fifth embodiment of the present invention. The basic operation is the same as that of the first embodiment shown in FIG. 4, but here, the processing using the broadcast information is performed to determine whether or not the retransmission execution condition in step S5 in FIG. 4 is met. Therefore, in the process S5 of FIG. 4, which is a retransmission execution determination, first, broadcast information is acquired (S17), and it is determined whether there is an instruction to perform retransmission relay in the broadcast information (S18). If there is no instruction, retransmission relay is terminated (S8). On the other hand, if there is an instruction to perform retransmission relay, retransmission relay is performed (S9). As in the case of FIG. 4, after the process S9 is performed, the process returns to the process S17, and the retransmission is repeated a predetermined number of times until there is no instruction to perform the retransmission in the broadcast information. The same applies to the new transmission of the wireless packet (S10). After the completion of the new transmission process, the process proceeds to the processes S17 and S18 corresponding to the process S5 in FIG. 4, and the same process is repeated. The broadcast information acquisition in step S17 here does not necessarily need to be a signal received at this timing, but if it is a signal that indicates an instruction corresponding to a radio packet in which time slot, another timing that is completely different. The instruction content in the received signal may be recorded and the information may be referred to here.

1-1 to 1-2 Base station 2-1 to 2-7, 3-1 to 3-7 Radio station 4-1 to 4-2 Radio packet 5-1 to 5-2 Service area of each base station 100 Network DESCRIPTION OF SYMBOLS 11 Base station 12-1-12-9 Radio station which performs resending relay 13 Destination radio station 21 Radio station apparatus 22 Radio | wireless part 23 Baseband signal processing part 24 Radio packet termination means 25 Interface part 26 Antenna 27 Communication control part 28 Identifier acquisition Means 29 Identifier match judgment means 30 Base station identifier acquisition means 31 Retransmission relay execution judgment means 32 Overall control unit 33 Retransmission counter acquisition means 34 Retransmission counter match judgment means 35 GPS, etc.

Claims (8)

Wireless communication that consists of one base station and a plurality of wireless stations, and transmits and receives wireless packets while performing direct or multi-hop relay between the base station and a wireless station of a communication partner in the wireless station In the device
The radio packet includes identifier information indicating a source radio station and a destination radio station,
The radio station is
Base station identifier acquisition means for acquiring identifier information of the base station to which the wireless station is to be connected via a wireless line;
Wireless packet receiving means for receiving the wireless packet;
Identifier obtaining means for obtaining identifier information indicating a source wireless station and a destination wireless station of the received wireless packet;
Identifier match determination means for determining whether any of the identifier information indicating the source radio station or the destination radio station acquired by the identifier acquisition means matches the identifier information of the base station or the identifier indicating the own station;
Retransmission execution determining means for determining whether or not to perform retransmission relay according to either a retransmission relay termination condition explicitly described in the wireless packet or a retransmission relay termination condition defined on the system; ,
It is determined by the identifier match determination means that either identifier information indicating a source radio station or a destination radio station matches the identifier information of the base station, and it is determined by the retransmission execution determination means that retransmission relay should be performed. A wireless packet transmitting means for transmitting one of the received or transmitted wireless packets as they are or after reconfiguring the information described in a predetermined field according to a predetermined condition,
A wireless packet terminating unit that terminates the received wireless packet and extracts data when the identifier matching determining unit determines that the identifier information indicating the destination wireless station matches the identifier information of the local station. A wireless communication device. The wireless communication device according to claim 1,
The wireless packet includes control information including a retransmission counter value that is information on the number of retransmission relays in a predetermined field,
The retransmission execution determining means includes
Retransmission counter value acquisition means for acquiring the retransmission counter value described in a predetermined field of the received wireless packet;
Retransmit counter value match determination means for determining whether or not the retransmit counter value matches a predetermined condition;
Further, the wireless packet transmitting means includes a retransmission counter updating means for adding or subtracting the retransmission counter value, and a wireless packet for reconstructing a wireless packet obtained by recording the updated retransmission counter value in a predetermined field And a wireless communication device. The wireless communication device according to claim 1,
The radio station and the base station communicate using a commonly recognized time slot,
The radio communication apparatus according to claim 1, wherein the retransmission execution determining means determines that retransmission has ended when a time slot in which the radio packet is received is a time slot that matches a predetermined periodic condition. The wireless communication device according to claim 1,
The base station includes control information notification means for reporting control information regarding whether or not to perform retransmission relay,
The radio station includes notification information acquisition means for acquiring information notified from the control information notification means of the base station,
The retransmission execution determining means is configured to compare the relationship between the information obtained by the broadcast information acquisition means and the time slot in which the radio packet is to be transmitted, and to determine whether retransmission relay should be performed or not. A wireless communication device. Wireless communication that consists of one base station and a plurality of wireless stations, and transmits and receives wireless packets while performing direct or multi-hop relay between the base station and a wireless station of a communication partner in the wireless station In the method
The radio packet includes identifier information indicating a source radio station and a destination radio station,
The radio station is
A base station identifier obtaining step for obtaining identifier information of the base station to which the radio station is to be connected via a radio line;
A radio packet receiving step for receiving the radio packet;
An identifier acquisition step of acquiring identifier information indicating a transmission source radio station and a destination radio station of the received radio packet;
An identifier match determination step for determining whether any of the acquired identifier information indicating the source radio station or the destination radio station matches the identifier information of the base station or the identifier indicating the own station;
A retransmission execution determining step for determining whether or not to perform retransmission relay according to either a retransmission relay termination condition explicitly described in the wireless packet or a retransmission relay termination condition defined on the system; ,
When it is determined in the identifier match determination step that either identifier information indicating a source radio station or a destination radio station matches the identifier information of the base station and it is determined in the retransmission execution determination step that retransmission relay should be performed A wireless packet transmission step for transmitting any of the received wireless packets as they are or after reconfiguring the information described in a predetermined field according to a predetermined condition,
A radio packet termination step for terminating the radio packet and extracting data when it is determined in the identifier match judgment step that the identifier information indicating the destination radio station matches the identifier information of the local station. Wireless communication method. The wireless communication method according to claim 5, wherein
The wireless packet includes control information including a retransmission counter value that is information on the number of retransmission relays in a predetermined field,
The retransmission execution determining step includes:
A retransmission counter value acquisition step of acquiring the retransmission counter value described in a predetermined field of the received wireless packet;
A retransmission counter value match determination step for determining whether or not the retransmission counter value matches a predetermined condition,
Including
Further, the wireless packet transmitting step includes a retransmission counter updating step for adding or subtracting the retransmission counter value, and a wireless packet for reconstructing a wireless packet obtained by recording the updated retransmission counter value in a predetermined field. A wireless communication method comprising: an update step. The wireless communication method according to claim 5, wherein
The radio station and the base station communicate using a commonly recognized time slot,
The wireless communication method according to claim 1, wherein the retransmission execution determining step determines that retransmission has ended when a time slot in which the wireless packet is received is a time slot that matches a predetermined periodic condition. The wireless communication method according to claim 5, wherein
The base station performs a control information notification step of notifying control information related to the availability of retransmission relay,
The radio station performs a notification information acquisition step of acquiring information notified from the control information notification means of the base station,
The retransmission execution determining step compares the information obtained by the broadcast information acquisition means with the time slot in which the wireless packet is to be transmitted, and determines whether retransmission relay should be performed or not. Communication method.

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