JP5431418B2 - Wireless communication system and wireless communication method - Google Patents

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 system 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. 9 shows an overview of routing in a prior art wireless multi-hop network.
In FIG. 9, 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. 9, 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. 9, 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. 9, 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. 9, 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. 10 shows a configuration example of a radio station apparatus in the prior art.
In FIG. 10, 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 performing the above routing process, the communication control unit 127 generates and terminates a request packet and a response packet. At that time, necessary information is managed as a database through the wireless metric management means 130 for managing the wireless metric value which is the communication state with the surrounding wireless stations.

  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 there is an unstable link somewhere on the route, that link is the communication characteristic of all routes. 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 system 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.

  A first aspect of the invention is a wireless packet that includes one base station and a plurality of wireless stations, and describes identifier information indicating a transmission source and a destination between the base station and a wireless station of a communication partner in the wireless station. In a wireless communication system that relays and retransmits a multi-hop, a base station and a wireless station transmit and receive a control signal in a frequency band lower than that of the first wireless communication unit that transmits and receives a wireless packet, and the first wireless communication unit. Scheduling information transmitted to the plurality of radio stations via the second radio communication unit as a control signal by generating scheduling information related to radio packet transmission and retransmission relay. The radio station includes a transmission unit, and the radio station performs scheduling related to radio packet transmission and retransmission relay from a control signal received via the second radio communication unit. Scheduling information receiving means for acquiring information, band request information transmitting means for generating band request information for transmitting a wireless packet, and transmitting it as a control signal to the base station via the second wireless communication means, A base station identifier acquiring means for acquiring an identifier of a base station connected via a wireless line, and an identifier indicating a transmission source or destination acquired from a wireless packet received via a first wireless communication means, Identifier matching judgment means for judging whether or not the identifier of the mobile station or the identifier indicating the own station, and the retransmission relay termination condition described in the wireless packet, or the retransmission relay termination condition defined on the system, or Retransmission relay for determining whether or not to perform retransmission relay of a wireless packet received via the first wireless communication unit according to any of the scheduling information When it is determined that the identifier indicating the transmission source or the destination matches the identifier of the base station by the execution determination unit and the identifier match determination unit, and the retransmission relay execution determination unit determines that the retransmission relay should be performed When the wireless packet transmitting means for transmitting the wireless packet received at the timing indicated by the scheduling information and the identifier match determination means determine that the identifier information indicating the destination matches the identifier information of the own station, the received wireless Wireless packet termination means for terminating the packet and extracting data.

  In the wireless communication system of the first invention, the first wireless communication means performs communication in a high frequency band exceeding 10 GHz, and the second wireless communication means performs communication in a low frequency band of 10 GHz or less.

  In the wireless communication system of the first invention, the scheduling information includes at least information for specifying a wireless packet, transmission start timing for transmission and retransmission relay, and information for determining whether to perform retransmission relay.

  In the wireless communication system of the first invention, the bandwidth request information transmitting means transmits the second wireless communication again when the bandwidth request information is transmitted as a control signal and a control signal including scheduling information is not received within a predetermined time. The bandwidth request information control signal is transmitted to the base station via the means.

  A second invention is a wireless packet that includes one base station and a plurality of wireless stations, and describes identifier information indicating a transmission source and a destination between the base station and a wireless station of a communication partner in the wireless station. In the wireless communication method for relaying retransmissions in multihop, the base station and the wireless station transmit and receive wireless packets using the first wireless communication means, and the first wireless communication means uses the first wireless communication means A step of transmitting and receiving a control signal in a frequency band lower than that of the wireless communication means, wherein the base station generates scheduling information related to transmission and retransmission relay of the wireless packet using the scheduling information transmitting means, and the second wireless communication means And transmitting the control signal as a control signal to a plurality of wireless stations via the second wireless communication means using the scheduling information receiving means. A step of obtaining scheduling information related to transmission and retransmission relay of a wireless packet from a received control signal, and bandwidth request information for transmitting the wireless packet is generated using bandwidth request information transmitting means, and the second wireless communication Transmitting as a control signal to the base station via the means, using the base station identifier obtaining means, obtaining an identifier of the base station to which the local station is connected via a wireless line, and identifier matching judgment means And determining whether the identifier indicating the transmission source or destination acquired from the wireless packet received via the first wireless communication means matches the identifier of the base station or the identifier indicating the own station; Using the retransmission relay execution determining means, the retransmission relay termination condition described in the wireless packet, or the retransmission relay termination condition defined on the system, Or determining whether to repeat or repeat the retransmission of the wireless packet received via the first wireless communication means according to any of the scheduling information, and using the wireless packet transmitting means, the identifier match determining means At the timing indicated in the scheduling information when it is determined that either the identifier indicating the source or the destination matches the identifier of the base station and the retransmission relay execution determining means determines that the retransmission relay should be performed. The step of transmitting the received wireless packet and the wireless packet termination unit terminate the received wireless packet when the identifier match determination unit determines that the identifier information indicating the destination matches the identifier information of the local station. Extracting data.

  In the wireless communication method of the second invention, the first wireless communication means performs communication in a high frequency band exceeding 10 GHz, and the second wireless communication means performs communication in a low frequency band of 10 GHz or less.

  In the wireless communication method of the second invention, the scheduling information includes at least information for specifying a wireless packet, transmission start timing for transmission and retransmission relay, and information for determining whether to perform retransmission relay.

  In the wireless communication method of the second invention, the bandwidth request information transmitting means transmits the second wireless communication again when the bandwidth request information is transmitted as a control signal and a control signal including scheduling information is not received within a predetermined time. A bandwidth request information control signal is transmitted to the base station via the means.

  The wireless communication system 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 a multi-hop manner 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, multiple wireless stations are involved in retransmission relay, so even if there are unstable links 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 system configuration example to which the retransmission relay in this invention is applied. It is a figure which shows the basic operation example of the retransmission relay in this invention. It is a figure which shows the basic structural example of the radio station apparatus in this invention. It is a figure which shows the basic processing flow of the retransmission relay in this invention. It is a figure which shows the operation example of the retransmission relay in the Example of this invention. It is a figure which shows the scheduling map information S-MAP in the Example of this invention. It is a figure which shows the processing flow of the low frequency band communication in the Example of this invention. It is a figure which shows the structural example of the radio station apparatus in the Example of this invention. It is a figure which shows the outline | summary of the routing in the radio | wireless multihop network of a prior art. It is a figure which shows the structural example of the radio station apparatus in a prior art.

  Embodiments of a wireless communication apparatus according to the present invention will be described below 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 a system configuration example to which the retransmission relay according to the present invention is applied.
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 a user in the area as one of control information for low frequency band communication described below. In this way, for example, the wireless stations 2-1 to 2-7 in the service area 5-1 recognize in advance that the identifier of the base station 1-1 that manages the 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 wireless packet 4-1 including a transmission source identifier “A” and a destination identifier “g” in the header area. Send. This wireless packet 4-1 is received by wireless 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” given 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. Assume that the wireless stations 2-1 to 2-3 that have received the wireless packet 4-1 under such conditions retransmit the wireless packet and the wireless stations 2-4 to 2-6 have received it. Similarly, these wireless stations 2-4 to 2-6 receive the wireless packet equivalent to the wireless packet 4-1, and recognize the transmission source identifier “A” and the destination identifier “g” given to the header area thereof. To do.

  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 radio packet is retransmitted and received by the radio station 2-7. The wireless station 2-7 recognizes the transmission source identifier “A” and the destination identifier “g” given to the header area of the received wireless packet, and recognizes that the destination identifier matches the identifier of the own station. 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 wireless station 3-7 generates a wireless packet 4-2 including a transmission source identifier “n” and a destination identifier “B” in the header area, and transmits this. This wireless packet is received by wireless stations 3-4 to 3-6 in the vicinity of the wireless 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” given 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. Assume that the wireless stations 3-4 to 3-6 that have received the wireless packet 4-2 under such conditions retransmit the wireless packet and that the wireless stations 3-1 to 3-3 have received it. Similarly, these wireless stations 3-1 to 3-3 receive a wireless packet equivalent to the wireless packet 4-2 and recognize the transmission source identifier “n” and the destination identifier “B” given to the header area. To do.

  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 wireless packet is retransmitted and received by the base station 1-2. The base station 1-2 recognizes the transmission source identifier “n” and the destination identifier “B” given to the header area of the received wireless packet, and recognizes that the destination identifier matches the identifier of the own station. 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 transmission source identifier “n” and the destination identifier “B” given to the header area of the received wireless packet. Since it does not match the identifier “A” of the base station 1-1 that manages the retransmission, retransmission relay is not performed.

  The above is the basic operation. The feature is that there are a plurality of radio stations that perform retransmission relay, and all of them transmit signals of 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. Since signals from multiple radio stations are combined and received on the receiving side, it is expected that there will be variations in characteristics for each radio station, but the gain is improved by the number of relay stations for 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.

FIG. 2 shows a basic operation example of retransmission relay in the present invention.
In FIG. 2, 11 is a base station, 12-1 to 12-6 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 12-6, and the destination radio station 13, and FIG. 2 (2) shows the transmission of each radio station in the time slots # 1 to # 8. Or a reception state is shown and a horizontal axis shows time.

  In time slot # 1, when the base station 11 transmits a radio packet to the radio station 13, the radio stations 12-1 to 12-2 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 12-2 perform retransmission relaying, and the radio stations 12-3 to 12-12. -4 receives this wireless packet. In the next time slot # 3, the base station 11 and the radio stations 12-1 to 12-2 that were transmitting in the previous time slot # 2 and the received radio stations 12-3 to 12-4 are relayed by retransmission. The wireless stations 12-5 to 12-6 receive this wireless packet. In the next time slot # 4, the base station 11 and the radio stations 12-1 to 12-4 that have been transmitting in the previous time slot # 3 and the radio stations 12-5 to 12-6 that have received the transmission operation The destination wireless station 13 receives this wireless packet. Thereby, the wireless packet transmitted by the base station 11 can be received by the destination wireless station 13.

  Similarly, when the wireless station 13 transmits a wireless packet addressed to the base station 11, when the wireless station 13 transmits a wireless packet in time slot # 5, the wireless stations 12-5 to 12-6 receive this wireless packet. . In the next time slot # 6, the wireless station 13 transmitting in the previous time slot # 5 and the receiving wireless stations 12-5 to 12-6 perform retransmission relay, and the wireless stations 12-3 to 12-12. -4 receives this wireless packet. In the next time slot # 7, the radio station 13 and radio stations 12-5 to 12-6 that were transmitting in the previous time slot # 6 and the radio stations 12-3 to 12-4 that have been receiving are relayed by retransmission. The wireless stations 12-1 to 12-2 receive the wireless packet. In the next time slot # 8, the radio station 13 and radio stations 12-3 to 12-6 that were transmitting in the previous time slot # 7 and the radio stations 12-1 to 12-2 that have been receiving are relayed by retransmission. The destination base station 11 receives this wireless packet. As a result, the radio packet transmitted by the radio station 13 can be received by the base station 11.

  Here, until a predetermined time slot, each wireless station continues to repeatedly transmit the received wireless packet. In this manner, the final radio packet delivery can be ensured by increasing the total transmission power.

FIG. 3 shows a basic configuration example of a radio station apparatus according to 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 the own station is different. 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, the header information attached to the wireless packet is taken out and transferred to the communication control unit 27. The communication control unit 27 manages the header information. The identifier acquisition unit 28 extracts the source identifier and the destination identifier 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, and when it is determined that the destination is the local station, the communication control unit 27 instructs the wireless packet termination unit 24 to output data, and the format-converted packet Is output to the outside by adjusting the electrical conditions and the like in the interface unit 25.

  On the other hand, when the identifier match determining unit 29 determines that the source identifier or the destination identifier is not addressed to the own station but matches the identifier of the base station to which the own station is connected, this result is used as the retransmission relay execution determining unit 31. The retransmission relay execution determination 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 obtained from a radio packet (including control information in low frequency band communication described below) received from the base station, or may be referred to from a database owned 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 the information based on information from another means other than the wireless system. 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. Similarly, equivalent processing can be performed in a circuit in which all or some of the functions are integrated in hardware.

  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, the operation for routing is specified, but here, since the wireless packet is 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 a basic processing flow of retransmission relay in the present invention.
In FIG. 4, when each wireless station receives a wireless packet (S1), it acquires a transmission source identifier and a destination identifier from predetermined fields of the received wireless packet (S2), and the destination identifier matches the identifier of its own station. 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 identifier or destination identifier matches the identifier of the base station that manages the own station (S4). The process is terminated as “none” (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 relay execution conditions are met, retransmission relay is performed (S9). The relay is terminated (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 relay 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, and how many times the retransmission relay is repeated until the retransmission relay is finished. 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 a 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 radio packet (S10), the transmitting station proceeds to the process S5 in the same manner as when the radio packet is received, and the subsequent processing is the same as when the radio packet is received and meets the retransmission relay implementation conditions. Whether or not to perform retransmission is determined, and depending on the result of the determination, retransmission relay termination (S8) or retransmission relay execution (S9) is performed.

  Here, the retransmission relay implementation condition in which the wireless station repeats the retransmission relay will be described. When the number of retransmissions at each radio station is specified as the retransmission relay execution condition, the following is performed. For example, the retransmission relay may be performed only once in the next time slot after receiving the wireless packet. Similarly, the number of times may be limited to twice, such as the next time slot after receiving the wireless packet and the next time slot only. In any case, retransmission relay is repeated at the previous wireless station, but the number of retransmissions at each wireless station is limited.

Further, when the time slot (hop count) in which the retransmission relay is continued is defined as the retransmission relay execution condition, it is as follows. As a condition for grasping the remaining number of retransmissions in a wireless packet, for example, a retransmission counter is recorded, and when there is a remaining number of retransmission counters when a wireless packet is received, retransmission relay is performed only for the remaining period. carry out. If the retransmission counter (hereinafter referred to as “RC”) indicates the remaining number of retransmissions, when RC = 2 is received, the counter value is subtracted by 1 at the time of the first retransmission relay, and RC = 1, the next retransmission At the time of relaying, RC = 0 is set, the counter value is updated, accommodated in a radio packet, and transmitted. The radio station that has received the radio packet with RC = 0 does not perform the next retransmission relay. That is, it is limited to retransmission relays up to the time slot (hop count) set in the retransmission counter by the wireless station that first transmitted the wireless packet. In this operation, the contents of the radio packet are changed every time the relay is retransmitted. However, since all the radio stations update the contents of the radio packet with the same rule, the same radio packet is eventually transmitted. It is possible to send.
In addition, the frame configuration may be defined, and for example, each retransmission relay may be performed only within the frame, and the retransmission relay may not be performed in the next frame, and the number of retransmission relays may be limited.

  The basic concept of retransmission relay described above is a technical feature of the invention described in the prior application (Japanese Patent Application No. 2011-082022).

Here, a technique for the base station to control a radio station existing in the service area of the base station will be specifically described.
As described above, the wireless communication system that is the subject of the present invention assumes that, for example, a millimeter wave band is used as a higher frequency band while avoiding a user-friendly microwave whose frequency resources are being depleted. As a typical example, let us assume a case where a 60 GHz band defined by a standard such as IEEE802.15.3c is used. First, the free space propagation loss L is given by the following equation with respect to the frequency f (wavelength λ), the distance R, and the speed of light C.
L = (4πR / λ) ² = (4πfR / C) ² (1)

  From equation (1), it can be seen that the loss increases as the frequency increases for the same distance. For example, if the 2.4 GHz band and the 60 GHz band, which are used as unlicensed microwave bands, are compared, the frequency will be 25 times. When compared in dB, the loss appears as a difference of about 28 dB.

  In general, it is known that a small high-gain antenna can be used when the frequency is high, and that a large antenna is required for high gain when the frequency is low. On the base station side, if too much directional antenna with a narrow beam width is used too much, it will not be possible to cover the service area all at once, and it is also possible to install a slightly larger antenna on the base station side In this case, it is assumed that the antenna gain that can be assumed on the base station side is not significantly affected by the difference between the frequency bands. On the other hand, on the general radio station side, since a small antenna is essential, it is inevitable that the antenna gain varies depending on the frequency. Assuming that this antenna gain difference is 10 dB, there is a line gain difference of about 18 dB depending on the frequency in the 2.4 GHz band and the 60 GHz band together with 28 dB according to the equation (1). For this reason, it is assumed that multi-hop relay is used in order to realize communication with a wireless station that cannot communicate directly in the millimeter wave band due to this line gain difference. Incidentally, the gain difference in the line design of 18 dB corresponds to the reachable transmission distance being quadrupled if the attenuation factor of the propagation loss in the transmission path is set to the third power. That is, if roughly estimated, an area that can be covered by multi-hop relay of several hops (for example, 4 hops) using millimeter waves can be directly communicated with a base station if it is a microwave.

  Originally, since frequency resources are being depleted in the microwave band, a high frequency band such as millimeter wave is assumed as a frequency band for performing broadband high-speed data communication. However, limited information such as control information is used. If there is, it is possible to realize communication by utilizing frequency resources in the microwave band. To put it in an extreme way, if it is possible to transmit 100 times the amount of information in the millimeter-wave band with abundant frequency resources using the few frequency resources in the microwave band, It may be considered that the band's frequency resources have been used 100 times more effectively.

  The present invention is based on the above assumption, and the base station and each radio station have a radio interface corresponding to two frequency bands, a high frequency band and a low frequency band, and data communication by retransmission relay of a prior application in the high frequency band. And transmitting / receiving a control signal including scheduling information for retransmission relay in a low frequency band so that retransmission relay is performed efficiently.

  Here, the high frequency band is a quasi-millimeter wave band or millimeter wave band exceeding 10 GHz, and data communication performed using the frequency band is referred to as high frequency band communication. The low frequency band is a microwave band of 10 GHz or less, and communication of control signals using the frequency band is called low frequency band communication.

FIG. 5 shows an operation example of retransmission relay in the embodiment of the present invention.
In FIG. 5, in a high frequency band (for example, a millimeter wave band), high frequency band communication is performed in which wireless packets such as user data are transferred at high speed over a wide band. On the other hand, in a low frequency band (for example, a microwave band) lower than the high frequency band, low frequency band communication for transferring a control signal including scheduling information for retransmission relay is performed. High frequency band communication and low frequency band communication are performed in parallel. In order to perform such multi-band communication, the base station 11, the radio stations 12-1 to 12-6, and the destination radio station 13 have a plurality of radio communication functions, and accordingly, an antenna for a high frequency band and An antenna for a low frequency band is provided.

  Here, for the sake of convenience, the time slots for high frequency band communication and low frequency band communication are illustrated as the same synchronized time slot, but the actual system design may have different slot lengths and the like, so the same time slot is not necessarily used. There is no need to use time slots.

  The procedure of retransmission relay in high frequency band communication is the same as the basic operation example shown in FIG. However, the base station 11 transmits scheduling map information S-MAP1 containing scheduling information in the downlink in accordance with the transmission in the time slot # 1 or in advance thereof, by low frequency band communication, The radio stations 12-1 to 12-6 and the destination radio station 13 receive them.

  In time slot # 1, the radio stations 12-1 to 12-2 receive the radio packet transmitted by the base station 11. The radio stations 12-1 to 12-2 perform retransmission relaying in the time slot # 2 indicated by the scheduling map information S-MAP1. The base station 11 also performs the second transmission in time slot # 2.

  In time slot # 2, radio stations 12-3 to 12-4 receive radio packets transmitted by base station 11 and radio stations 12-1 to 12-2. The radio stations 12-3 to 12-4 perform retransmission relaying in the time slot # 3 indicated by the scheduling map information S-MAP1. In addition, the base station 11 performs the third transmission, and the wireless stations 12-1 to 12-2 perform the second retransmission relay.

  In time slot # 3, the radio stations 12-5 to 12-6 receive the radio packets transmitted by the base station 11 and the radio stations 12-1 to 12-4. The radio stations 12-5 to 12-6 perform retransmission relaying in time slot # 4 indicated by the scheduling map information S-MAP1. The base station 11 performs the fourth transmission, the wireless stations 12-1 to 12-2 perform the third retransmission relay, and the wireless stations 12-3 to 12-4 perform the second retransmission relay. For example, even when a wireless station other than the wireless stations 12-5 to 12-6 receives a wireless packet in time slot # 3, the scheduling map information S-MAP1 must instruct retransmission relay of the wireless station. In this case, retransmission relay is not performed.

  In time slot # 4, the destination radio station 13 receives and terminates radio packets transmitted by the base station 11 and the radio stations 12-1 to 12-6.

  On the other hand, for example, when the wireless station 13 makes a bandwidth request in the uplink, the bandwidth request information Req is transmitted in low frequency band communication. Here, a case where transmission is performed in time slot # 5 is shown. When the base station 11 receives the bandwidth request information Req in the time slot # 5, the base station 11 transmits the scheduling map information S-MAP2 in which the scheduling information of the time slots # 7 to # 10 in the uplink is written in the time slot # 6 at a low frequency. The wireless stations 12-1 to 12-6 and the wireless station 13 receive the data through band communication.

  In the time slot # 7, the wireless station 13 transmits a wireless packet in the time slot # 7 indicated by the scheduling map information S-MAP2, and the wireless stations 12-5 to 12-6 receive the wireless packet. The radio stations 12-5 to 12-6 perform retransmission relaying in the time slot # 8 indicated by the scheduling map information S-MAP2. The wireless station 13 also performs the second transmission. Similarly, in time slots # 8 to # 10, the wireless stations 12-1 to 12-6 repeat retransmission of wireless packets according to the instruction of the scheduling map information S-MAP2 and reach the base station 11.

  Although the description is omitted here, in the above retransmission relay, as described in the above basic operation, the identifier contained in the received wireless packet is referred to, and the identifier is the identifier of the own station or the own station. Retransmission relay is performed based on the determination result of whether or not it matches the identifier of the base station to be managed. Further, the scheduling map information includes an identifier of the base station as shown below, and it is determined whether or not the received scheduling map information should be followed by the own station. Furthermore, when determining the base station to which the local station should be connected, if the low frequency band communication can be received from a plurality of base stations, the base station having the highest received signal strength of the low frequency band communication is selected. You can connect.

  Note that the high frequency band communication needs to operate at a timing at which the base station 11 and the wireless stations 12-1 to 12-6 and 13 are synchronized. For example, in the case of a system using the OFDM modulation scheme, the base station 11 and each of the radio stations 12-1 to 12-6 and 13 can synchronize symbol timing and also identify time slots composed of a plurality of OFDM symbols. It is set so that. For this timing synchronization, for example, GPS may be used, or signals in other wireless systems such as high frequency band communication or low frequency band communication, a radio clock, etc. may be used.

  In the scheduling map information S-MAP 1 and 2, various conditions related to retransmission relay are described. For example, (1) a condition indicating which radio packet is related to, (2) transmission start timing, ( 3) Includes information for determining whether to perform retransmission relaying.

  Regarding (1) above, for example, a wireless station that starts transmission sets an ID (serial number or the like) for identifying a wireless packet in a wireless packet according to some condition, and the received wireless station has an ID for identifying the wireless packet. Is associated with which time slot corresponds to which radio packet. The radio station 13 serving as the uplink transmission source knows the bandwidth allocation to the own station by using the scheduling map information S-MAP2, and transmits the ID for identifying the radio packet described here as the identification ID of the radio packet to be transmitted. Use. As for the identification ID of this wireless packet, it is possible to substitute, for example, the identifier of the source wireless station and the identifier of the destination wireless station in addition to the serial number described above, and the time slot in which the wireless packet is received It is also possible to operate by estimating which wireless packet corresponds to the information on the information.

  Regarding the above (2), in addition to the case of indicating by the time slot number that can be recognized by both the base station and the terminal station as shown in FIG. A serial number may be assigned to the symbol timing to instruct which symbol timing should be used to start transmission (or reception). This timing information can be managed by, for example, a counter having a predetermined number of bits, and may be expressed as a modulo value such that the value makes a round when the symbol length that can be managed by the number of bits is exceeded.

  With regard to (3) above, all the radio stations in the area may be grouped by some method, and it may be instructed which radio station to which the group belongs should perform retransmission relay. For example, if there are a large number of wireless stations and it is not necessary for all the stations to perform retransmission relay at the same time, an instruction such as a wireless station whose identification number ends with a binary display “1” may be used. Similarly, each radio station may generate a random number, and only a radio station having a predetermined value or less (or more) may perform retransmission relaying. Furthermore, an instruction using position information or the like may be used. In addition, an instruction may be given that the upper limit number of retransmission relays is limited to a wireless station up to the second time. This upper limit number of times can also be changed every turn based on, for example, the number of radio stations that can participate in retransmission relay.

FIG. 6 shows scheduling map information S-MAP in the embodiment of the present invention.
In FIG. 6, the scheduling map information S-MAP includes overall control information 31 and information elements 32-1 to 32-8. The content of the information accommodated in the scheduling map information S-MAP is as described above. As an example of the specific image, the configuration of the information accommodated in the scheduling map information configured as one radio packet. Is shown here.

  Here, an example is shown in which uplink allocation is performed simultaneously with downlink data transmission. In the head part of the scheduling map information, the overall control information 31 is accommodated as control information relating to the whole. Here, by specifying the identifier (AP-ID) of the base station, the base station of which base station in which area is subordinate. Indicates whether the information is addressed to the radio station. Here, as a method for matching the recognition of the time slot numbers of the base station and the radio station, for example, a combination of a serial number for a relatively long cycle frame and a time slot number as local address information in each frame In such a case, a long-period frame number (Fr #) is accommodated in the overall control information 31, and the local time slot number (TS #) in the frame is an information element 32. It is efficient to describe in -1 to 32-8. Further, the overall control information 31 may contain the number of information elements 32-1 to 32-8 (# of IE) accommodated in the scheduling map information. In this case, the number of information elements 32-1 to 32-8 can be variably set for each frame, and as a result, the frame length can be set to be different every time.

  Next, an example of information accommodated in each information element 32-1 to 32-8 will be described. In this example, in addition to the time slot number (TS #), an identifier (S-ID) of a source radio station and an identifier (D-ID) of a destination radio station of a radio packet to be transmitted are given, and each radio A sequence number (SN) is assigned to the packet. As described above, any sequence number may be used, and here, a common serial number is assigned to all radio packets in the high frequency band communication related to the base station “A”. Therefore, the same sequence number “1” is assigned to each information element 32-1 to 32-4 along with regenerative relay, and the same sequence number “2” is assigned to each information element 32-5 to 32-8. Yes. Furthermore, although it is not essential, direction indication (Dir) of the downlink direction (DL) and the uplink direction (UL) is performed as a signal flow.

  Further, as to whether or not retransmission relay is possible, in order to perform retransmission relay in the time slots # 2 to # 4 and time slots # 6 to # 8, information elements 32-2 to 32-4 and 32-6 to 32- In the relay instruction (Relay) in FIG. 8, “Yes” indicating relay execution is written. On the other hand, in the time slots # 1 and # 5 corresponding to the initial transmission, the relay instruction (Relay) of the information elements 32-1 and 32-5 means that relaying is impossible with the intention of stopping the retransmission relay accompanying the new transmission. “No” is written. Furthermore, as a retransmission condition, an upper limit number of retransmission relays to be performed after receiving the wireless packet indicated by the information element is indicated as a retransmission counter (RC). For example, when the wireless packet indicated by the information element 32-1 is received in time slot # 1, it is recognized that the upper limit of the number of times that the wireless packet is retransmitted is 3 times (RC: 3). Can do. Similarly, when the wireless packet indicated by the information element 32-2 is retransmitted in time slot # 2, after the wireless packet is transmitted, the upper limit of the number of retransmissions is 2 (RC: 2). Therefore, consistency with the instruction by the previous information element 32-1 is ensured. In this way, it is possible to accommodate the retransmission counter and other information together in the scheduling map information.

  This situation is the same for the information elements 32-5 to 32-8 related to the uplink. In the information element 32-5, since the identifier “z” of the transmission source radio station and the identifier “A” of the destination radio station are instructed, the radio station “z” transmits the uplink bandwidth to the own station. You can know that the assignment has been made.

  The above is an example, and the scheduling map information may be described in any other format. If the system adopts OFDMA, the assigned subcarrier number should also be included in this scheduling map information, and if it is adaptive modulation that changes the transmission rate every moment, the transmission mode (QPSK, 16QAM, etc.) And error correction coding rate, etc.), packet length instructions, and other various information may be stored here. Of course, the above-mentioned part may be omitted.

  Also, here, an example has been shown in which retransmission relay instruction is performed using only scheduling map information of low frequency band communication, but information transmitted in high frequency band communication and information transmitted in low frequency band communication You may give instructions in combination. For example, in FIG. 6, retransmission counter information (RC) is also accommodated in the scheduling map information for low frequency band communication. However, even if such information is accommodated in data for high frequency band communication, the same operation is performed. Is possible. Assuming that the slot length of each time slot is variable for each communication, the length of one slot is reported by the scheduling map information of low frequency band communication, while one frame as a rule on the system. If there is a precondition that retransmission is not performed over 4 frames and exceeds the frame, a combination of information broadcast in the low frequency band communication and a retransmission relay termination condition defined on the system, On the time axis, it is also possible to grasp how far to repeat retransmission. In this way, it may be configured to determine whether or not to perform retransmission relay based on a combination of information broadcast in low frequency band communication and other information. At this time, it is known in which combination the base station and the terminal station determine whether to perform retransmission relay.

  The bandwidth request information described above is control information for a general bandwidth request, and the content thereof may be any. Normally, it includes the identifier of the base station to which the bandwidth request is made, the identifier of the terminal station, the size of the radio packet (may be a symbol length considering the transmission speed), etc., and if necessary, multi-hop to the base station The number of relay hops (the number of required retransmission relays) and other information may be included.

  The operation flow of retransmission relay related to high frequency band communication in the embodiment of the present invention is basically the same as the processing shown in FIG. 4, and in the case of the operation shown in FIG. Judgment is made on whether or not the condition is in agreement with the condition designated by the scheduling map information S-MAP 1 and 2 received by the frequency band communication. Taking the scheduling map information of FIG. 6 as an example, the Relay information for each time slot number (TS #) is Yes, and the retransmission counter (RC) is 1 or more in the information element corresponding to the immediately preceding time slot. Something is used in condition judgment. Further, taking FIG. 6 as an example, the retransmission counter (RC) is 0 in time slots # 4 and # 8 where retransmission relay should be terminated, so that retransmission relay is not continued in the next time slot. Can be recognized. On the other hand, in time slots # 2 to # 4 and # 6 to # 8, “Yes” indicating relay execution is written in the relay instruction (Relay), so retransmission relay is executed in these time slots.

  FIG. 7 shows a processing flow relating to low frequency band communication in the embodiment of the present invention. Fig. 7 (a) shows the processing flow when downlink data is transmitted from the base station in the high frequency band communication, and Fig. 7 (b) shows the processing when the radio station makes an uplink bandwidth request to the base station. FIG. 7C shows a processing flow when the base station receives a bandwidth request from the radio station. These processes can be performed concurrently with the high frequency band communication.

  In FIG. 7 (a), when it is determined that there is data to be transmitted on the downlink of the high frequency band communication from the base station to the subordinate radio station (S11), the data is transmitted on the downlink of the high frequency band communication. Scheduling related to transmission of the radio packet to be performed is performed (S12). Here, in addition to the initial transmission, scheduling is also performed that includes retransmission relay. The result is generated as scheduling map information S-MAP (S14), the scheduling map information S-MAP is transmitted by low frequency band communication (S14), and the process is terminated (S15).

  Next, in FIG. 7B, when it is determined that there is data to be transmitted from the radio station to the base station via the uplink (S16), band request information is generated (S17), and the band request information is changed to the low frequency. Transmit by band communication (S18). If the reception of the scheduling map information S-MAP related to the uplink allocation of the local station cannot be confirmed within a predetermined time (S19), the process returns to the process S18 again to transmit the bandwidth request information (S18). On the other hand, when the reception of the scheduling map information S-MAP relating to the uplink allocation of the own station can be confirmed, the radio packet is transmitted in accordance with the instruction of the scheduling map information S-MAP in the high frequency band communication, and the processing Is finished (S20).

  Next, in FIG. 7 (c), when the base station receives the bandwidth request information transmitted in step S18 of FIG. 7 (b) (S21), scheduling of high frequency band communication including transmission and retransmission relay is performed. Implementation (S22), scheduling map information S-MAP is generated based on the result (S23), scheduling map information S-MAP is transmitted (S24), and the process is terminated (S25).

  Note that any wireless standard may be used for low frequency band communication. An original standard may be established for this wireless system, or an existing wireless standard such as IEEE802.11 or WiMAX (Worldwide interoperability for microwave access) may be used as it is. For example, in the case of IEEE 802.11, in processing S14, processing S18, processing S24, etc., it is necessary to perform carrier sense before transmitting a wireless packet and to confirm beforehand that it is not in a low frequency band used for other communication and interference. is there. At the start of communication in high frequency band communication, scheduling map information must be transmitted in advance or at the timing, so if the scheduling map information transmission is delayed by a certain amount of time due to carrier sense, etc., the scheduling content is realized. However, in this case, it is necessary to modify the scheduling map information before transmission.

FIG. 8 shows a configuration example of a radio station apparatus in the embodiment of the present invention.
In FIG. 8, the radio station apparatus of the present embodiment has a configuration in which a control signal radio function unit 33 and an antenna 34 are added to the basic configuration of the radio station apparatus shown in FIG. The basic operation is the same as that in FIG. 3, but the low frequency band communication different from the high frequency band communication is enabled by mounting the control signal radio function unit 33 and the antenna 34.

  The signal received by the antenna 34 is subjected to signal processing for low frequency band communication by the control signal radio function unit 33, and control information obtained as a result is input to the communication control unit 27. The transmission / reception operation is performed in accordance with the control information obtained here, and information regarding retransmission relay is also transferred to the retransmission relay execution determination unit 31, and the retransmission relay execution determination unit 31 determines whether or not retransmission relay can be performed. That is, based on this control information, the retransmission condition determination in the process S5 of FIG. 4 is performed. When performing retransmission relaying, radio packet generation and transmission processing are performed.

  In the wireless station, when data is input from the outside to the interface unit 25 and input to the wireless packet terminator 24 and then a request for signal transmission to the base station is input to the communication control unit 27, the communication control unit 27 A transmission request for band request information in the low frequency band communication is input to the control signal wireless function unit 33, where the band request information is generated and transmitted through the antenna 34 as the low frequency band communication. Here, the control signal wireless function unit 33 is collectively shown, but here, all of RF signal processing, baseband signal processing, MAC layer signal processing, and the like are included.

  In the above description, the control signal transferred in the low frequency band communication has been described with the scheduling information including the retransmission relay execution determination information and the band request information as a representative example, but any other control signal is transmitted in the low frequency band. You may transfer by communication. Conversely, it is not necessary for all control signals to be performed in low frequency band communication.

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 12-1-12-1 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 determination means 30 Base station identifier acquisition means 31 Retransmission relay execution determination means 32 Overall control section 33 Control signal radio function section 34 Antenna

Claims (8)

A wireless packet that includes one base station and a plurality of wireless stations, and that describes identifier information indicating a transmission source and a destination in a multi-hop manner between the base station and a wireless station of a communication partner in the wireless station. In a wireless communication system that relays retransmissions,
The base station and the wireless station include: a first wireless communication unit that transmits and receives the wireless packet; and a second wireless communication unit that transmits and receives a control signal in a lower frequency band than the first wireless communication unit. Prepared,
The base station includes scheduling information transmission means for generating scheduling information related to transmission and retransmission relay of the radio packet and transmitting the scheduling signal as the control signal to the plurality of radio stations via the second radio communication means,
The radio station is
Scheduling information receiving means for obtaining scheduling information related to transmission and retransmission relay of the wireless packet from the control signal received via the second wireless communication means;
Band request information transmitting means for generating band request information for transmission of the radio packet and transmitting as the control signal to the base station via the second radio communication means;
Base station identifier acquisition means for acquiring an identifier of the base station to which the local station is connected via a wireless line;
Identifier match determination for determining whether an identifier indicating a transmission source or a destination acquired from the wireless packet received via the first wireless communication means matches an identifier of the base station or an identifier indicating the own station Means,
The radio received via the first radio communication unit in accordance with either the retransmission relay end condition described in the radio packet, the retransmission relay end condition defined on the system, or the scheduling information Retransmission relay execution determining means for determining whether or not to perform retransmission relay of a packet;
When it is determined by the identifier match determination means that either the identifier indicating the transmission source or the destination matches the identifier of the base station, and when the retransmission relay execution determination means determines that retransmission relay should be performed, Wireless packet transmitting means for transmitting the wireless packet received at the timing indicated by the scheduling information;
Radio identifier termination means for terminating the received radio packet and extracting data when the identifier match determination means determines that the identifier information indicating the destination matches the identifier information of the local station. Wireless communication system. The wireless communication system according to claim 1, wherein
The wireless communication system, wherein the first wireless communication unit performs communication in a high frequency band exceeding 10 GHz, and the second wireless communication unit performs communication in a low frequency band of 10 GHz or less. The wireless communication system according to claim 1, wherein
The wireless communication system, wherein the scheduling information includes at least information for identifying the wireless packet, transmission start timing for transmission and retransmission relay, and information for determining whether to perform retransmission relay. The wireless communication system according to claim 1, wherein
The band request information transmitting means transmits the band request information as the control signal again, and when the control signal including the scheduling information is not received within a predetermined time, the band request information transmitting means again passes through the second wireless communication means. A wireless communication system, wherein the control signal of the bandwidth request information is transmitted to the base station. A wireless packet that includes one base station and a plurality of wireless stations, and that describes identifier information indicating a transmission source and a destination in a multi-hop manner between the base station and a wireless station of a communication partner in the wireless station. In a wireless communication method for relay retransmission,
The base station and the radio station perform transmission and reception of the radio packet using a first radio communication unit, and control in a lower frequency band than the first radio communication unit using a second radio communication unit The step of transmitting and receiving signals;
The base station generates scheduling information regarding transmission and retransmission relay of the radio packet using scheduling information transmission means, and transmits the scheduling information as the control signal to the plurality of radio stations via the second radio communication means. Have
The radio station is
Using scheduling information receiving means to obtain scheduling information related to transmission and retransmission relay of the wireless packet from the control signal received via the second wireless communication means;
Generating bandwidth request information for transmission of the wireless packet using bandwidth request information transmitting means, and transmitting the control signal to the base station via the second wireless communication means;
Using the base station identifier acquisition means, acquiring the identifier of the base station to which the own station is connected via a wireless line;
Whether the identifier indicating the transmission source or destination acquired from the wireless packet received via the first wireless communication means using the identifier matching determination means matches the identifier of the base station or the identifier indicating the own station Determining whether or not,
Using the retransmission relay execution determining means, according to either the retransmission relay termination condition described in the wireless packet, the retransmission relay termination condition defined on the system, or the scheduling information, Determining whether to repeat or terminate retransmission of the wireless packet received via the communication means; and
Using wireless packet transmission means, it is determined that either the identifier indicating the source or the destination matches the identifier of the base station by the identifier match determination means, and retransmission relay should be performed by the retransmission relay execution determination means Transmitting the wireless packet received at the timing indicated by the scheduling information when it is determined,
Using the wireless packet termination means, and terminating the received wireless packet and extracting data when the identifier match determination means determines that the identifier information indicating the destination matches the identifier information of the own station. A wireless communication method. The wireless communication method according to claim 5, wherein
The wireless communication method, wherein the first wireless communication means performs communication in a high frequency band exceeding 10 GHz, and the second wireless communication means performs communication in a low frequency band of 10 GHz or less. The wireless communication method according to claim 5, wherein
The scheduling information includes at least information for identifying the radio packet, transmission start timing for transmission and retransmission relay, and information for determining whether to perform retransmission relay. The wireless communication method according to claim 5, wherein
The band request information transmitting means transmits the band request information as the control signal again, and when the control signal including the scheduling information is not received within a predetermined time, the band request information transmitting means again passes through the second wireless communication means. The wireless communication method, wherein the control signal of the bandwidth request information is transmitted to the base station.

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