JP5161651B2 - Wireless device and control program for wireless device - Google Patents

Description

  The present invention relates to a radio apparatus and a control program for the radio apparatus.

  A relay technique is widely known as a technique for extending the communication distance of a wireless device. The relay technology is a technology that causes the wireless device A to pass through the wireless device C located between the wireless devices A and B when transmitting a wireless signal to the wireless device B. Even if the communication quality between the wireless devices A and B is poor by using the relay technology, if the communication quality between the wireless devices A and C and between the wireless devices BC is good, the wireless device A- Communication quality between B can be improved.

  However, using the relay technology in this way can increase the communication distance of the wireless device, but has a problem that the throughput is reduced. For example, when the same frequency channel is used for communication between the wireless devices A and C and communication between the wireless devices B and C, communication between the wireless devices A and C and between the wireless devices BC are performed at the same time. This is a problem that the throughput is reduced by half.

  As described above, when the wireless device A transmits a wireless signal to the wireless device B, the wireless device A directly transmits the wireless signal to the wireless device B according to the measurement result of the communication quality between the wireless devices A and B. (Hereinafter referred to as a direct communication method) or wireless transmission of a wireless signal to the wireless device B via the wireless device C (hereinafter referred to as a relay method) is determined. I was sending a signal.

  If the communication environment deteriorates when the wireless device is transmitting a wireless signal by the direct communication method, there is a problem that the throughput is significantly reduced. On the other hand, there is a problem that the throughput is not improved as expected even if the communication environment is improved when the wireless device transmits a wireless signal by the relay method.

  In order to solve such a problem, a technique is disclosed in which a wireless device dynamically switches between a direct communication method and a relay method according to a communication environment (for example, Patent Document 1).

  In the technique disclosed in Patent Document 1, protocol processing for switching the communication method is performed every time the wireless device switches between the direct communication method and the relay method.

  On the other hand, an SDMA (Space Division Multiple Access) method is known as a spatial multiplexing technique in order to effectively use frequency channels. The SDMA scheme is a technique for increasing uplink transmission capacity (capacity) by simultaneously transmitting radio signals from a plurality of radio apparatuses to a radio base station.

For example, a wireless base station polls a plurality of wireless devices. The plurality of wireless devices that have received the polling transmit wireless signals to the wireless base station simultaneously and using the same frequency channel. The radio base station spatially separates a plurality of radio signals transmitted from the respective radio devices and receives them simultaneously (for example, Patent Document 2).
JP2007-165980 JP2007-208522A

  In the conventional relay technique disclosed in Patent Document 1 and the like, the throughput when transmitting a radio signal by the relay method is almost halved compared to the throughput when the radio signal is transmitted by the direct communication method. There was a problem that.

  Furthermore, if the direct communication method and the relay method are dynamically switched according to changes in the communication environment, protocol processing for switching the communication method is required, and overhead is generated.

  The present invention has been made to solve the above-described problems of the prior art, and suppresses a decrease in throughput even when the communication environment deteriorates, and promptly increases the throughput when the communication environment improves. It is an object of the present invention to provide a wireless device and a wireless device control program that can be improved.

In order to achieve the above object, a wireless device according to an embodiment of the present invention is a wireless device that relays a wireless signal, and identifies whether there is a possibility of relaying a wireless signal from another wireless device. A first storage means for storing identification information for receiving, a receiving means for receiving a first wireless signal having the first wireless device as a transmission source and a second wireless device as a destination, and the first wireless signal being relayable A determination unit that determines whether or not the wireless signal is a radio signal according to the identification information; and when the determination unit determines that there is a possibility of relaying the first wireless signal, the first wireless signal is temporarily When the second storage device stores the delivery confirmation signal for notifying the wireless signal that the second wireless device has successfully received from the second wireless device, it is temporarily stored in the second storage device. Of the radio signals that are Transmission means for transmitting to the second wireless device a second wireless signal that is not notified of successful delivery to the second wireless device by an arrival confirmation signal, wherein the transmitting means transmits the second wireless signal in accordance with the delivery confirmation signal. The second radio signal transmitted in accordance with the delivery confirmation signal from the transmission means of the own radio apparatus, in which the transmission period overlaps with the period in which the first radio device retransmits the third radio signal according to the delivery confirmation signal And the third wireless signal retransmitted from the first wireless device according to the delivery confirmation signal is transmitted to the second wireless device by a spatial multiplexing method, and the delivery confirmation signal received from the second wireless device is transmitted to the second wireless device. Describes spatial multiplexing information for transmission to the second radio apparatus by a spatial multiplexing method, and the delivery confirmation signal is not only the own radio apparatus but also the first radio apparatus. It is received, the transmission unit, in accordance with the spatial multiplexing information, and transmits by the second spatial multiplexing radio signal to the second wireless device.

  According to the present invention, it is possible to suppress a decrease in throughput even when the communication environment is deteriorated, and to quickly improve the throughput when the communication environment is improved.

  Hereinafter, embodiments of the present invention will be described.

(First embodiment)
FIG. 1 is a diagram illustrating a configuration of a network according to the first embodiment.

  The network according to the first embodiment includes a wireless device 1, a wireless device 2, and a wireless device 3. The wireless devices 1, 2, and 3 communicate with each other by transmitting and receiving wireless signals. The wireless device 3 relays a wireless signal transmitted from the wireless device 2 to the wireless device 1.

  Hereinafter, an outline of an operation when the wireless device 3 relays a wireless signal transmitted from the wireless device 2 to the wireless device 1 will be described.

  First, the wireless device 2 transmits a signal for requesting the wireless device 3 to relay a wireless signal transmitted from the wireless device 2 to the wireless device 1 (hereinafter referred to as a cooperation request signal). . When receiving the cooperation request signal, the wireless device 3 determines that the wireless signal designated by the cooperation request signal is a wireless signal that may be relayed in the future, and temporarily stores the wireless signal.

  Here, for example, the cooperation request signal is determined to be a radio signal that may be relayed in the future from a radio signal that has the radio device 2 as a transmission source and a radio device 1 as a destination.

  Next, after transmitting the cooperation request signal, the wireless device 2 transmits a wireless signal to the wireless device 1. The wireless signal transmitted from the wireless device 2 is received not only by the wireless device 1 but also by the wireless device 3.

  Next, since the wireless signal transmitted from the wireless device 2 to the wireless device 1 is a wireless signal specified by the cooperation request signal, the wireless device 3 temporarily stores the wireless signal.

  Next, the wireless device 1 returns a signal (hereinafter, referred to as a delivery confirmation signal) for notifying a wireless signal that has been successfully received among the wireless signals from the wireless device 2 to the wireless device 2. The delivery confirmation signal transmitted from the wireless device 1 is received not only by the wireless device 2 but also by the wireless device 3.

  Next, the wireless device 2 retransmits to the wireless device 1 a wireless signal that has not been notified that the reception has been successful by the delivery confirmation signal. At the same time, the wireless device 3 transmits, to the wireless device 1, a temporarily stored wireless signal among wireless signals not notified of successful reception by the delivery confirmation signal. The wireless device 2 and the wireless device 3 transmit a wireless signal to the wireless device 1 simultaneously and using the same frequency channel by a spatial multiplexing method.

  In this way, the wireless device 3 relays the wireless signal designated by the cooperation request signal from the wireless device 2 to the wireless device 1.

  In the above description, it is assumed that one radio apparatus 3 relays a radio signal transmitted from the radio apparatus 2 to the radio apparatus 1.

  However, two or more wireless devices 3-1 to 3-n (n is an integer equal to or larger than 2) may relay the wireless signal transmitted from the wireless device 2 to the wireless device 1. At this time, the wireless device 2 transmits a cooperation request signal to the wireless devices 3-1 to 3-n. The operations of the radio apparatuses 3-1 to 3-n are the same as the operation of the radio apparatus 3 described above. The wireless devices 2 and 3-1 to 3-n that have received the delivery confirmation signal transmit the wireless signal to the wireless device 1 at the same time and using the same frequency channel by the spatial multiplexing method.

  Hereinafter, a cooperation request signal transmitted from the wireless device 2 to the wireless device 3 will be described.

  The cooperation request signal is a signal for requesting relay of a radio signal, and is designated with “a radio device that performs relay processing”, “a radio signal that performs relay processing”, and “relay destination”. Any signal can be used as long as it is possible.

  In the above example, the cooperation request signal designates the “wireless device that performs relay processing” as the wireless device 3, and the “wireless signal that performs relay processing” designates the wireless device 1 as the transmission source and the wireless device 2 as the destination. The signal is designated as a signal, and the “relay destination” is designated as the wireless device 2.

  The cooperation request signal includes a cooperation identifier. The cooperation identifier is information for designating “a radio signal to be relayed” (what kind of radio signal is requested to be relayed). When the wireless device 3 receives the cooperation request signal, the wireless signal specified by the cooperation identifier included in the cooperation request signal is determined as a wireless signal that may be relayed in the future.

  When the wireless device (for example, wireless device 3) that has received the cooperation request signal correctly receives the wireless signal designated by the cooperation identifier, the wireless signal may be transmitted even if the destination address of the wireless signal is not the own wireless device. Is temporarily stored.

  Next, examples of cooperative identifiers are listed.

(1) The cooperative identifier may be a set of terminal identifiers (for example, MAC addresses) of two wireless devices. The wireless device that has received the cooperation request signal temporarily stores the received wireless signal when the source address and the destination address of the received wireless signal match the cooperation identifier (a set of MAC addresses of two wireless devices). To do.

(2) The cooperative identifier may specify a set of terminal identifiers of two wireless devices and a frame type (for example, data frame) of a wireless signal. The wireless device that has received the cooperation request signal is a case where the source address and the destination address of the received wireless signal match the cooperation identifier (a set of MAC addresses of two wireless devices), and the received wireless signal frame When the type is specified by the cooperation identifier, the received radio signal is temporarily stored.

(3) The cooperative identifier may be a set of terminal identifiers of two wireless devices and QoS information. The wireless device that has received the cooperation request signal is a case where the source address and the destination address of the received wireless signal match the cooperation identifier (a set of MAC addresses of the two wireless devices), and the QoS of the received wireless signal. When the information matches the designation of the cooperation identifier, the received radio signal is temporarily stored.

(4) The cooperation identifier may define a specific number. At this time, a cooperation identifier field is provided in the frame of the radio signal. The wireless device that has received the cooperation request signal temporarily stores the received wireless signal when the number described in the cooperation identifier field of the received wireless signal matches the number specified by the cooperation identifier.

  The cooperation identifier included in the radio signal may be added as PHY header information or MAC header information of the radio signal, or may be added as part of preamble information.

  When the cooperation identifier is added to the MAC header information, the wireless device 3 receives the MAC frame, interprets the MAC header information, and then determines whether to temporarily store the wireless signal.

  When the cooperation identifier is added to the PHY header information, the wireless device 3 can determine whether to perform temporary storage at the PHY level (interpret the PHY header information). For this reason, the wireless device 3 can determine whether or not to temporarily store the wireless signal without activating the processing unit of the MAC layer, thereby preventing power consumption.

  When the cooperation identifier is added to a part of the preamble information, the wireless device 3 can determine the necessity of temporary storage at an earlier stage, and thus further power consumption can be reduced.

  In the first embodiment, the cooperation identifier is not limited to (1) to (4), and may be a combination of (1) to (4) or other methods.

  Hereinafter, a radio signal transmitted from the radio apparatus 2 to the radio apparatus 1 and a delivery confirmation signal returned from the radio apparatus 2 to the radio apparatus 1 will be described.

  The delivery confirmation signal is a signal for the wireless device 1 to notify a wireless signal that has been successfully received. The delivery confirmation signal is also a signal for the wireless device 2 to notify the wireless signal that has been successfully delivered to the wireless device 1.

(Transmission method 1)
FIG. 2 is a diagram illustrating a delivery confirmation signal returned from the wireless device 1 when the wireless device 2 transmits the aggregated MAC frame.

  First, the wireless device 2 transmits to the wireless device 1 a PHY frame (hereinafter, an aggregation signal) obtained by aggregating (aggregating) a plurality of MAC frames (information frames). The information frame is a MAC frame having a MAC header, information (data), and CRC (Cyclic Redundancy Check).

  Next, the wireless device 1 receives the aggregation signal.

  Next, the wireless device 1 collects information (information 1, information 3) that has been successfully received from a plurality of pieces of information (information 1, information 2, information 3) included in the aggregation signal by using a delivery confirmation signal. Send back.

  In the delivery confirmation signal, the sequence number (SN: Sequence Number) of the MAC frame (information) that has been successfully received may be described. In the delivery confirmation signal, “1” is described only in the bitmap corresponding to the MAC frame (information) that has been successfully received among the bitmaps corresponding to each of the plurality of MAC frames (information) included in the aggregation signal. May be.

(Transmission method 2)
FIG. 3 is a diagram illustrating a delivery confirmation signal returned by the wireless device 1 when the wireless device 2 transmits an aggregate signal and transmits a delivery confirmation signal.

  First, the wireless device 2 transmits an aggregation signal to the wireless device 1.

  Next, the wireless device 1 receives the aggregation signal.

  Next, the wireless device 2 transmits a delivery confirmation request signal to the wireless device 1. The delivery confirmation request signal is a signal that requests the destination wireless device (wireless device 1) to return a delivery confirmation signal.

  Next, the wireless device 1 receives a delivery confirmation request signal.

  Next, the wireless device 1 collects information (information 1, information 3) that has been successfully received from a plurality of pieces of information (information 1, information 2, information 3) included in the aggregation signal by using a delivery confirmation signal. Send back.

(Transmission method 3)
FIG. 4 is a diagram illustrating a delivery confirmation signal returned from the wireless device 1 when the wireless device 2 continuously transmits a plurality of PHY frames.

  First, the wireless device 2 continuously transmits a plurality of PHY frames including one MAC frame (information frame) to the wireless device 1.

  Next, the wireless device 1 receives a plurality of PHY frames transmitted from the wireless device 2.

  Next, the wireless device 2 transmits a delivery confirmation request signal to the wireless device 1.

  Next, the wireless device 1 returns a delivery confirmation signal for notifying the wireless device 2 of information (information 1, information 3) that has been successfully received.

(Transmission method 4)
FIG. 5 is a diagram illustrating a delivery confirmation signal returned by the wireless device 1 when the wireless device 2 transmits a wireless signal including one unit for frame error checking.

  First, the wireless device 2 transmits to the wireless device 1 a wireless signal including one unit for performing a frame error check. A radio signal including one unit for performing a frame error check is a radio signal designated by one sequence number. The radio signal transmitted from the radio apparatus 2 to the radio apparatus 1 illustrated in FIG. 5 corresponds to Aggregated-MSDU defined by the IEEE 802.11n standard.

  Next, the wireless device 1 delivers information (information 1) that has been successfully received with respect to information (information 1 (including information 1_1, information 1_2, and information 1_3)) included in the PHY frame received from the wireless device 2. Reply with a confirmation signal.

  FIG. 6 is a block diagram illustrating a configuration of the wireless device 3 according to the first embodiment.

  The wireless device 3 includes a reception unit 10, a transmission unit 20, a control unit 30, a cooperation management unit 40, an identifier storage unit 50, and a cooperation frame storage unit 60.

  The identifier storage unit 50 stores the cooperation identifier described in the cooperation request signal.

  The cooperative frame storage unit 60 stores a wireless signal addressed to another wireless device and designated by a cooperation identifier.

  FIG. 7 is a flowchart showing an outline of the operation of the wireless device 3 when a wireless signal is received.

  First, the receiving unit 10 of the wireless device 3 determines whether the received wireless signal is addressed to the own wireless device (hereinafter, addressed to the own station) or to another wireless device (hereinafter, addressed to the other station). (Step S101).

  When the received wireless signal is addressed to the own station (“addressed to own station” in step S101), the receiving unit 10 next determines whether or not the received wireless signal is a cooperation request signal (step S102).

  When the received wireless signal is a wireless signal other than the cooperation request signal (“No” in step S102), the receiving unit 10 performs normal reception processing. The receiving unit 10 outputs a radio signal addressed to itself to the control unit 30. When the radio signal is an information frame, the control unit 30 outputs the information frame to an upper layer. When the wireless signal is a control signal, the control unit 30 performs processing according to the control signal.

  On the other hand, when the received radio signal is a cooperation request signal (“Yes” in step S102), the receiving unit 10 writes the cooperation identifier described in the cooperation request signal in the identifier storage unit 50 (step S104).

  If the received wireless signal is addressed to another station (“addressed to other station” in step S101), then the receiving unit 10 determines whether the received wireless signal is designated as a cooperative identifier stored in the identifier storage unit 50 It is determined whether or not (step S105).

  When it is determined that the radio signal is not designated as the cooperation identifier (“No” in step S105), the receiving unit 10 discards the radio signal (step S106).

  On the other hand, when it is determined that the wireless signal is designated as the cooperation identifier (“No” in step S105), the reception unit 10 further determines whether or not the signal is a delivery confirmation signal (step S107).

  When it is determined that the signal is not a delivery confirmation signal (“No” in step S107), the receiving unit 10 writes the radio signal in the cooperative frame storage unit 60 (step S108). Here, the receiving unit 10 does not write the radio signal in which the error is detected to the cooperative frame storage unit 60, and only the radio signal in which no error is detected (may be only the MAC frame). You may write to Note that when the MAC frame is written in the cooperative frame storage unit 60, the MAC header including the sequence number, the destination address, the transmission source address, and the like added by the wireless device 2 is written in the cooperative frame storage unit 60. This makes it easy to generate a radio signal to be transmitted.

  On the other hand, when a radio signal is transmitted not by a spatial multiplexing method but by a normal transmission method as shown in FIG. 9B to be described later, time information on the time length of a frame received erroneously (time for waiting for transmission) is also included. Either keep it, or keep it in error frames. And when producing | generating the radio signal to transmit, it waits for transmission in the meantime using the hold | maintained time information. Alternatively, when generating a radio signal, a time to wait for transmission is calculated based on the stored error frame, and a radio signal to be transmitted is generated. As a holding method, if there is a sufficient amount of memory, the frame generation process can be omitted by holding all received radio signals as analog signals including frames received in error.

  On the other hand, when it is determined that the signal is a delivery confirmation signal (“Yes” in step S107), the wireless device 3 performs coordinated transmission (step S109). The receiving unit 10 determines whether or not to perform cooperative transmission from the cooperative identifier stored in the identifier storage unit 50 and information on the delivery confirmation signal (for example, the transmission source address and the destination address of the delivery confirmation signal). . When determining that the cooperative transmission is to be performed, the receiving unit 10 outputs a delivery confirmation signal to the cooperative management unit 40. The cooperation management unit 40 outputs the wireless signal that has been received by the wireless device that has transmitted the delivery confirmation signal and has been stored in the cooperation frame storage unit 60 to the cooperation frame storage unit 60. Instruct. The cooperation frame storage unit 60 outputs a radio signal to the transmission unit 20 in accordance with an instruction from the cooperation management unit 40. The cooperation management unit 40 outputs information (spatial multiplexing information) necessary for transmitting the radio signal by the spatial multiplexing method to the transmission unit 20. The transmission unit 20 transmits the radio signal output from the cooperative frame storage unit 60 according to the spatial multiplexing method in accordance with the spatial multiplexing information output from the cooperation management unit 40. In this way, the wireless device 3 performs coordinated transmission.

  In the following, when the communication between the wireless device 1 and the wireless device 2 is performed in each of the transmission methods 1 to 4 described above, the wireless device 3 relays a radio signal transmitted from the wireless device 2 to the wireless device 1 (cooperation). (Transmission) will be described. Note that the wireless device 3 relays (cooperative transmission) a wireless signal in which the wireless device 2 is a transmission source address and the wireless device 1 is a destination address.

(Transmission method 1)
FIG. 8 is a diagram illustrating radio signals transmitted and received by the radio apparatuses 1, 2, and 3 when cooperative transmission is performed in the transmission method 1.

  First, the wireless device 2 transmits a PHY frame including five MAC frames (information frames). The header part of each information frame includes a sequence number (SN = 1, 2, 3, 4, 5). Each information frame includes a CRC for determining whether or not the information frame has been correctly received.

  A PHY frame transmitted from the wireless device 2 (a wireless signal whose transmission source is the wireless device 2 and whose destination is the wireless device 1) is received by the wireless device 3 and temporarily stored. It is assumed that the wireless device 3 has successfully received an information frame with SN = 1, 2, 3, 4, 5.

  Next, the wireless device 1 receives the PHY frame transmitted from the wireless device 2.

  Next, for each of the five information frames included in the received PHY frame, the wireless device 1 determines the success or failure of reception using the CRC included in each information frame.

  Next, the wireless device 1 transmits to the wireless device 2 a delivery confirmation signal that describes each information frame that has been successfully received. Since the wireless device 1 cannot determine the number of information frames that have failed to be received, the wireless device 1 notifies the wireless device 2 of information frames that have been successfully received, instead of notifying the wireless device 2 of information frames that have failed to be received. FIG. 8 shows a delivery confirmation signal when the wireless apparatus 2 has successfully received the information frame with SN = 1, 3, and 5 and has not received the information frame with SN = 2, 4.

  The wireless device 1 returns a delivery confirmation signal after a fixed time (SIFS (Short Inter Frame Space)) after receiving the wireless signal from the wireless device 2. The wireless device 1 transmits a delivery confirmation signal to the received wireless signal. When the timing for performing the reply is described, the delivery confirmation signal may be returned according to the timing.

  Next, the wireless device 2 determines that the information frame of SN = 2, 4 has not been delivered correctly by the received delivery confirmation signal, and retransmits the information frame of SN = 2, 4.

  On the other hand, the wireless device 3 also determines that the information frame of SN = 2, 4 has not been correctly delivered by the received delivery signal, and temporarily stores the information frame among the information frames that have been judged to have not been delivered correctly Is transmitted (coordinated transmission) to the wireless device 1.

  Hereinafter, details of the delivery confirmation signal transmitted by the wireless device 1 and operations of the wireless devices 2 and 3 according to the delivery confirmation signal will be described.

  First, with reference to FIGS. 8A and 8B, a method of notifying the information frame that the wireless device 1 has successfully received will be described. The delivery confirmation signal returned from the wireless device 1 to the wireless device 2 may be any signal as long as the wireless device 1 can notify the information frame that has been successfully received. In addition, there are various types of information added to the delivery confirmation signal depending on the environment and type of the system. In the delivery confirmation signal shown in FIGS. 8A and 8B, information (information related to the sequence number) necessary for notification of information about the information frame that has been successfully received (hereinafter, delivery confirmation information) is described. It was supposed to be.

  In FIG. 8A, the wireless device 1 receives the information to the wireless device 2 by describing the sequence number (SN = 1, 3, 5) of the information frame successfully received by the wireless device 1 in the delivery confirmation signal. It is a figure which shows a mode that a successful information frame is notified.

  When the number of sequence numbers described in the delivery confirmation signal is variable, a field for notifying the number of sequence numbers described in the delivery confirmation signal is newly provided in the delivery confirmation signal. When the number of sequence numbers described in the delivery confirmation signal is fixed (a fixed number), the field for notifying the number of sequence numbers described in the delivery confirmation signal becomes unnecessary.

  FIG. 8B shows the information frame that the wireless device 1 has successfully received to the wireless device 2 by describing a bitmap for notifying the information frame that the wireless device 1 has successfully received in the delivery confirmation signal. It is a figure which shows a mode that it notifies. FIG. 8B shows that the wireless device 1 has successfully received the information frame corresponding to “1” and has not received the information frame corresponding to “0”.

  Bi (i is an integer equal to or greater than 1) = “1” indicates that the wireless device 1 has successfully received an information frame having a sequence number “SSN + i−1” (SSN: Starting Sequence Number). Bi (i is an integer equal to or greater than 1) = “0” indicates that the wireless device 1 has not received the information frame having the sequence number “SSN + i−1”.

  FIG. 8B shows that the wireless apparatus 1 has successfully received information frames with SN = 1, 3, 5 and has not received information frames with SN = 2, 4, 6, and 7. Since the wireless device 1 has not yet received an information frame having a sequence number of 6 or more, B6, B7... Are set to “0”.

  Note that, when the radio apparatus 1 has successfully received all (SN = 1 to 5) information frames, the radio apparatus 1 may describe that the cooperative transmission is unnecessary in the delivery confirmation signal.

  Next, information that is added to the delivery confirmation signal and is necessary for the wireless device 2 and the wireless device 3 that have received the delivery confirmation signal to transmit a wireless signal by the spatial multiplexing method (hereinafter referred to as spatial multiplexing information). ).

  Any spatial multiplexing method may be used when the wireless devices 2 and 3 according to the first embodiment transmit a wireless signal to the wireless device 1. Hereinafter, a method disclosed in Patent Document 2 (Japanese Patent Application Laid-Open No. 2007-208522) will be described as an example.

  First, the wireless device 1 adds, as spatial multiplexing information, a transmission method when the wireless device 1 transmits a training symbol and a transmission method when the wireless device 3 transmits a training symbol to the delivery confirmation signal. In addition, the terminal identification of the radio | wireless apparatus (for example, radio | wireless apparatus 3) which requests | requires cooperative transmission may be added to the delivery confirmation signal.

  The training symbol is information for the wireless device 1 to perform propagation path estimation between the wireless device 1 and the wireless device 3.

  A transmission method for transmitting the training symbols by the wireless devices 2 and 3 is specified so that the training symbols transmitted by the wireless device 2 and the training symbols transmitted by the wireless device 3 are orthogonal.

  The terminal identifier of the wireless device 3 may be any information that can be specified by the wireless device 3. For example, the MAC address of the wireless device 3, a temporary identifier determined in advance negotiation, or a temporary assigned during advance negotiation It may be a typical identifier (for example, AID (Association ID)).

  Next, the wireless device 1 returns a delivery confirmation signal added with the spatial multiplexing information to the wireless device 2. The delivery confirmation signal to which the spatial multiplexing information is added is also received by the wireless device 3.

  Next, the radio apparatuses 2 and 3 transmit training symbols according to the training symbol transmission method described in the delivery confirmation signal, and then transmit data. The wireless device 1 performs propagation path estimation between the wireless device 1 and the wireless device 2 using the training symbol transmitted from the wireless device 2. The wireless device 1 performs propagation path estimation between the wireless device 1 and the wireless device 3 using the training symbol transmitted from the wireless device 3.

  The wireless device 1 uses the propagation path estimation result between the wireless device 1 and the wireless device 2 and the propagation path estimation result between the wireless device 1 and the wireless device 3 from the wireless device 2 and the wireless device 3. Radio signals transmitted by the spatial multiplexing method are spatially separated and received.

  Further, transmission of radio signals from the radio apparatuses 2 and 3 to the radio apparatus 1 may be performed in accordance with a MIMO (Multi Input Multi Output) scheme.

  In this case, since one wireless device may transmit a plurality of streamings, the delivery confirmation signal describes the number of streaming when the wireless device 2 and the wireless device 3 transmit the wireless signal to the wireless device 1. .

  When the identifier of the wireless device 3 that requests the coordinated transmission and the number of streaming when the wireless devices 2 and 3 transmit the wireless signal are described in the delivery confirmation signal, the wireless device 2 and the wireless device 3 deliver A training symbol is transmitted according to the specification of the confirmation signal.

  Thus, by adding the spatial multiplexing information to the delivery confirmation signal, the radio signals transmitted by the radio apparatuses 2 and 3 can be spatially separated when received by the radio apparatus 1.

  Next, the timing at which the radio apparatuses 2 and 3 transmit radio signals by the spatial multiplexing method after receiving the delivery confirmation signal will be described.

  Information related to timing for spatial multiplexing may be added to the spatial multiplexing information of the delivery confirmation signal so that the timings at which the radio apparatus 2 and the radio apparatus 3 transmit radio signals coincide with each other.

  For example, in a system in which the timing at which the wireless devices 2 and 3 transmit a wireless signal after receiving the delivery confirmation signal is variable, the waiting time until the wireless signal is transmitted after receiving the delivery confirmation signal is set as the delivery confirmation. It may be described in the signal.

  Further, for example, the wireless device 1 grasps the propagation delay time of the wireless signal transmitted from the wireless devices 2 and 3 and transmits the wireless signal between the wireless device 2 and the wireless device 3 by the difference (correction amount) of the propagation delay time. The timing to do can be changed. By doing so, it is possible to correct (synchronize) the transmission timings of the wireless devices 2 and 3 so that the wireless signals received by the wireless device 1 can be easily spatially separated. Thus, by synchronizing the transmission timing of the radio signal by the radio apparatuses 2 and 3 with higher accuracy, overhead such as a guard interval can be reduced and communication efficiency can be improved.

  Further, in order to accurately control the transmission timing, the wireless device 1 may calculate the correction amount according to the position information of each wireless device 1, 2, and 3 by a position positioning system such as GPS (Global Positioning System). good.

  Furthermore, each of the wireless devices 1, 2, and 3 may include a highly accurate timepiece such as an atomic clock, and the wireless device 1 may calculate a correction amount according to the time information.

  In addition, if the wireless device 2 and the wireless device 3 preliminarily specify that the wireless signal is transmitted after a fixed time (SIFS) has elapsed after receiving the delivery confirmation signal, the wireless device 2 and the wireless device 3 When transmitting a wireless signal by the spatial multiplexing method, information about the timing of transmitting the wireless signal is not necessarily required. By doing so, the information amount of the delivery confirmation signal can be reduced, so that the communication efficiency can be improved.

  Furthermore, the spatial multiplexing information added to the delivery confirmation signal is not transmitted to the wireless device 2 so that the wireless device 1 can easily separate the wireless signals transmitted from the wireless devices 2 and 3 by the spatial multiplexing method. Information for transmission power control and information for transmission power control for the wireless device 3 may be added.

  At this time, the wireless devices 2 and 3 transmit wireless signals by the spatial multiplexing method according to the information for transmission power control described in the delivery confirmation signal.

  By doing in this way, since the radio | wireless apparatus 1 can receive the radio signal transmitted from the radio | wireless apparatuses 2 and 3 with equal electric power, respectively, it can improve a space separation characteristic. At this time, it is not necessary to add information about the transmission method of the training symbol by adding information for transmission power control to the delivery confirmation signal.

  Furthermore, the wireless device 1 can spatially separate the wireless signals transmitted from the wireless device 2 and the wireless device 3 by forming a directional beam by itself.

  Furthermore, in order to improve the spatial separation characteristic, the radio signals 2 and 3 can be transmitted by a directional beam (radio wave having directivity).

  At this time, in order to further improve the spatial separation specification, the channel information (CSI: Channel State Information) between the wireless device 1 and the wireless device 2 and the wireless device 1 are added to the spatial multiplexing information added to the delivery confirmation signal. And channel information between the wireless device 2 and the wireless device 2 may be added.

  For example, by receiving a delivery confirmation signal to which channel information between the wireless device 1 and the wireless device 2 is added, the wireless device 3 that performs cooperative transmission improves the spatial separation characteristics in the wireless device 1 Wireless signals can be controlled.

  Further, for example, it becomes possible to add beam control information (for example, a weighting factor) when each wireless device 2 or 3 transmits to the delivery confirmation signal. In this way, the wireless device 1 can cause the wireless devices 2 and 3 to transmit a wireless signal using a desired directional beam.

  The description of the details of the delivery confirmation signal transmitted by the wireless device 1 and the operations of the wireless devices 2 and 3 according to the delivery confirmation signal is completed.

  In the above description, it is assumed that the wireless device 3 has successfully received all five information frames (SN = 1 to 5) transmitted from the wireless device 2. Next, the case where the wireless apparatus 3 has successfully received only the information frame of SN = 4 among the five information frames will be described.

  First, it is assumed that the wireless device 3 receives a delivery confirmation signal from the wireless device 1 in the same manner as described above. The delivery confirmation signal indicates that the wireless device 1 has successfully received information frames with SN = 1, 3, 5 and has not received information frames with SN = 2, 4.

  Next, the wireless device 3 transmits the temporarily stored information frame (SN = 4) among the information frames (SN = 2, 4) not received by the wireless device 1 to the wireless device 1.

  FIG. 9 is a diagram illustrating a method in which the wireless device 3 transmits an information frame when the wireless device 3 temporarily stores only a part of the information frame that has not been received by the wireless device 1.

  First, the wireless device 2 and the wireless device 3 receive a delivery confirmation signal from the wireless device 1.

  Next, the wireless device 2 retransmits information frames of SN = 2 and 4.

  On the other hand, the wireless device 3 transmits (coordinated transmission) an information frame of SN = 4. The wireless device 3 transmits a wireless signal as shown in FIG. 9A or 9B.

  FIG. 9A is a diagram illustrating an information frame of SN = 4 transmitted by the wireless device 3 by the spatial multiplexing method.

  FIG. 9B is a diagram illustrating an information frame of SN = 4 transmitted by the wireless device 3 by a normal transmission method (other than the spatial multiplexing method). “PHY header”, “MAC header 4”, “information 4”, and “CRC 4” illustrated in FIG. 9B are “PHY header”, “MAC header 4”, and “information 4” transmitted by the wireless device 1. "And" CRC4 "are completely identical.

  After transmitting the “PHY header”, the wireless device 3 waits for a time required for the wireless device 2 to transmit the information frame of SN = 2, and thereafter, the “MAC header 4”, “information 4”, and “ CRC4 "is transmitted.

  In this way, when the wireless device 1 receives the wireless signal transmitted from the wireless devices 2 and 3, the wireless device 1 receives (synthesizes) the wireless signal transmitted from the single wireless device by multipath. ) Is equivalent to Therefore, the radio apparatuses 2 and 3 do not need to transmit radio signals by the spatial multiplexing method. However, when transmitting the information frame of SN = 2, 4, the wireless device 2 does not transmit a new information frame and transmits information such as a header when the information frame of SN = 2, 4 is retransmitted. There is a need (restriction) that should not be changed.

  The wireless device 1 does not describe the terminal identifier of the wireless device that requests cooperative transmission in the delivery confirmation signal, such as when the communication quality between the wireless device 1 and the wireless device 2 is good, and cooperates with the wireless device 3. By not transmitting, it is possible to request the wireless device 2 to transmit not only information frames with SN = 2 and 4 but also information frames with SN = 6, 7, 8, etc.

(Transmission method 2)
FIG. 10 is a diagram illustrating radio signals transmitted and received by the radio apparatuses 1, 2, and 3 when coordinated transmission is performed in the transmission method 2.

  First, the wireless device 2 transmits a PHY frame including an information frame with SN = 1 to 5 to the wireless device 1.

  Next, the wireless device 2 transmits a PHY frame including an information frame with SN = 6 to 10 to the wireless device 1.

  Next, the wireless device 2 transmits a PHY frame including an information frame of SN = 11 to 15 to the wireless device 1.

  Here, it is assumed that the wireless device 3 has successfully received all the information frames with SN = 1 to 15 and temporarily stores all the information frames.

  Next, the wireless device 2 transmits a delivery confirmation request signal to the wireless device 1.

  Next, after receiving the delivery confirmation request signal, the wireless device 1 returns a delivery confirmation signal to the wireless device 2. The delivery confirmation signal illustrated in FIG. 10 indicates that the wireless apparatus 1 has successfully received the information frames of SN = 1, 3, 5, 8, 12, and 15 among the information frames of SN = 1 to 15. The delivery confirmation signal transmitted from the wireless device 1 is also received by the wireless device 3.

  In the delivery confirmation signal, information required when the wireless device 2 and the wireless device 3 transmit a wireless signal by the spatial multiplexing method (spatial multiplexed information), and a terminal identifier (wireless device 3) of the wireless device that requests coordinated transmission. Terminal identifier).

  Next, the wireless device 2 transmits a PHY frame including information frames of SN = 2, 4, 6, 7, 9 to the wireless device 1 by the spatial multiplexing method according to the spatial multiplexing information described in the delivery confirmation signal. .

  On the other hand, since the wireless device 3 is also requested to perform coordinated transmission by the delivery confirmation signal, the PHY frame including the information frames of SN = 2, 4, 6, 7, and 9 according to the spatial multiplexing information described in the delivery confirmation signal, It transmits to the wireless device 1 by the spatial multiplexing method.

  Note that the wireless device 3 has one aggregation described in a wireless signal (for example, a cooperation request signal) transmitted at the time of prior negotiation for performing cooperative transmission, a delivery confirmation request signal transmitted from the wireless device 2, or the like. The number of aggregations is determined according to the upper limit of the number of MAC frames included in the signal (hereinafter, the number of aggregations).

  Next, the wireless device 2 transmits a PHY frame including information frames of SN = 10, 11, 13, 14, 16 to the wireless device 1 by the spatial multiplexing method according to the spatial multiplexing information described in the delivery confirmation signal. .

  On the other hand, the wireless device 3 transmits a PHY frame including information frames of SN = 10, 11, 13, and 14 to the wireless device 1 according to the spatial multiplexing method according to the spatial multiplexing information described in the delivery confirmation signal.

  Thus, the wireless devices 2 and 3 end the retransmission of the information frame according to the delivery confirmation signal.

  Further, next, the wireless device 2 transmits a PHY frame including an information frame of SN = 17 to 21 to the wireless device 1.

  Next, the wireless device 2 transmits a delivery confirmation request signal to the wireless device 1.

  Subsequent operations of the wireless devices 1, 2, and 3 are continued in the same manner as described above, and are therefore omitted. In this way, the wireless device 2 transmits a wireless signal to the wireless device 1, and the wireless device 3 transmits a wireless signal to the wireless device 1 (cooperative transmission).

  The difference between the transmission method 1 and the transmission method 2 is that the wireless device 1 does not transmit the delivery confirmation signal immediately after receiving the wireless signal from the wireless device 2, but the delivery confirmation request signal from the wireless device 2. This is a point of transmitting a delivery confirmation signal after receiving.

  In the transmission method 2, the wireless device 2 can continuously transmit a plurality of aggregation signals to the wireless device 1 before transmitting the delivery confirmation signal.

  If the wireless device 2 generates a PHY frame (aggregation signal) including a large number of information frames and transmits it to the wireless device 1, the data amount (signal length) of one PHY frame increases. Therefore, the time required to transmit one PHY frame becomes long, and the channel environment between the wireless device 2 and the wireless device 1 changes during that time, and the error rate of the latter half of the PHY frame increases. There is a drawback. Therefore, the wireless device 2 should not extremely increase the data amount (signal length) of one PHY frame.

  On the other hand, if the wireless device 2 receives the delivery confirmation signal every time it transmits the aggregation signal, there is a problem that transmission / reception of the delivery confirmation signal becomes overhead and transmission efficiency is lowered.

  In the transmission method 2, the wireless device 2 transmits a plurality of aggregation signals and then transmits a delivery confirmation request signal to confirm whether or not the information frame has been successfully delivered to the wireless device 1.

  The wireless device 2 transmits the delivery confirmation request signal as one PHY frame. However, information requesting the delivery confirmation signal may be added to the aggregation signal, and a plurality of MAC frames included in the aggregation signal may be added. One of them may be a delivery request signal. In any case, the wireless device 1 returns a delivery confirmation signal after receiving the delivery confirmation request signal (or information corresponding to the delivery confirmation request signal) from the wireless device 2.

  In this way, the wireless device 2 can add and transmit a new information frame during retransmission of the information frame even when the wireless device 3 performs cooperative transmission. Communication efficiency can be improved.

  In the transmission method 2, after receiving the delivery confirmation signal from the wireless device 1, the wireless devices 2 and 3 may continuously transmit the wireless signal a plurality of times by the spatial multiplexing method. Therefore, it is necessary for the wireless devices 2 and 3 to grasp the time interval for each time when performing continuous transmission of wireless signals by using a delivery confirmation request signal, a delivery confirmation signal, or the like.

(Transmission method 3)
In the transmission method 2, a plurality of MAC frames are included in the PHY frame that the wireless device 2 continuously transmits to the wireless device 1. However, in the transmission method 3, one MAC frame is included in the PHY frame that the wireless device 2 continuously transmits to the wireless device 1.

  As shown in FIG. 4, in the transmission method 3, the wireless device 2 continuously transmits PHY frames for each information frame and collectively receives delivery confirmation signals for the PHY frames.

  First, the wireless device 2 continuously transmits a plurality of PHY frames including one MAC frame (information frame) to the wireless device 1, and then transmits a delivery confirmation request signal. Note that the wireless device 2 can request the delivery confirmation signal by various methods described in the transmission method 2.

  Next, the wireless device 1 returns a delivery confirmation signal for notifying information that has been successfully received among the information included in the plurality of PHY frames received continuously from the wireless device 2. This delivery confirmation signal is also received by the wireless device 3.

  Next, the wireless device 2 retransmits the information frame that is not received by the wireless device 1 by the delivery confirmation signal.

  On the other hand, the wireless device 3 transmits (coordinated transmission) the information frame that is not received by the wireless device 1 by the delivery confirmation signal and is temporarily stored to the wireless device 1.

  In this way, the wireless device 3 can perform cooperative transmission even when the wireless device 2 and the wireless device 1 are communicating by the transmission method 3.

(Transmission method 4)
As illustrated in FIG. 5, in the transmission method 4, each time the wireless device 2 transmits one wireless signal, a delivery confirmation signal corresponding to the transmitted wireless signal is received.

  However, if the wireless device 1 successfully receives the information frame transmitted from the wireless device 2, the wireless device 1 returns a delivery confirmation signal. If the reception of the information frame transmitted from the wireless device 2 fails, the wireless device 1 returns a delivery confirmation signal. Do not send. This is because, when there is an error in the received information frame, the wireless device 1 cannot determine whether or not to return a delivery confirmation signal for the information frame.

  Here, a case where the wireless device 2 transmits an information frame to the wireless device 1 but the wireless device 1 fails to receive is considered.

  In the transmission method 4, when the wireless device 2 transmits an information frame to the wireless device 1, but does not return a delivery confirmation signal from the wireless device 1, the wireless device 2 retransmits the information frame.

  In order to enable cooperative transmission from the wireless device 3 even when such an information frame is retransmitted, in order to synchronize the timing at which the wireless device 2 retransmits and the timing at which the wireless device 3 performs cooperative transmission, The processing shown in FIG.

  FIG. 11 is a diagram illustrating radio signals transmitted and received by the radio apparatuses 1, 2, and 3 when the radio apparatus 1 fails to receive a radio signal from the radio apparatus 2 in the transmission method 4.

  First, the wireless device 2 transmits an information frame of SN = 1 to the wireless device 1. The information frame transmitted from the wireless device 2 is received not only by the wireless device 1 but also by the wireless device 3.

  Here, it is assumed that the wireless device 1 has failed to receive the information frame from the wireless device 2. It is assumed that the wireless device 3 has successfully received the information frame from the wireless device 2.

  At this time, the wireless device 1 does not send back a delivery confirmation signal. On the other hand, the wireless devices 2 and 3 wait for a response of a delivery confirmation signal returned from the wireless device 1.

  Next, the wireless device 2 retransmits the information frame of SN = 1 when a predetermined time has elapsed without receiving the delivery confirmation signal from the wireless device 1.

  On the other hand, similarly to the wireless device 1, the wireless device 3 also transmits (cooperative transmission) an information frame with SN = 1 when a predetermined time has elapsed.

  Here, the wireless device 1 and the wireless device 3 determine how long a retransmission / cooperative transmission should be performed after a wireless signal is transmitted from the wireless device 1 and no acknowledgment signal is returned. I remember.

  However, the delivery confirmation signal is not returned from the wireless device 1, and the wireless devices 2 and 3 do not receive information (spatial multiplexed information) necessary for transmitting the wireless signal by the spatial multiplexing method.

  Therefore, as described in FIG. 9B of the transmission method 1, the wireless device 3 transmits a wireless signal that is the same as or part of the wireless signal transferred by the wireless device 2.

  By doing in this way, the radio | wireless apparatus 1 can synthesize | combine and receive as a signal transmitted from the radio | wireless apparatus 2 and the radio | wireless apparatus 3 was transmitted by multipath, and improves communication quality. Can do.

  FIG. 12 is a diagram illustrating radio signals transmitted and received by the radio apparatuses 1, 2, and 3 when the radio apparatus 1 fails to receive a radio signal from the radio apparatus 2 in the transmission method 4.

  After the wireless device 2 transmits the information frame to the wireless device 1, the wireless device 1 fails to receive the information frame and the wireless devices 2 and 3 are in the standby state, which is the same as FIG.

  Next, when the wireless device 2 determines that the delivery confirmation signal is not returned from the wireless device 1, the wireless device 2 transmits to the wireless device 3 a spatial multiplexing request signal for requesting transmission of the wireless signal that has failed to be transmitted by the spatial multiplexing method. To do.

  Next, the wireless device 2 retransmits the information frame of SN = 1 that failed to be transmitted to the wireless device 1.

  On the other hand, in response to the spatial multiplexing request signal received from the wireless device 2, the wireless device 3 transmits (coordinated transmission) an information frame with SN = 1 by the spatial multiplexing method. In the spatial multiplexing request signal, information necessary for the wireless device 3 to transmit a wireless signal by the spatial multiplexing method and information about the timing at which the wireless device 3 transmits the wireless signal are described.

  By doing in this way, even when the wireless devices 2 and 3 do not receive the delivery confirmation signal from the wireless device 1, the wireless signals can be retransmitted / cooperatively transmitted by the spatial multiplexing method.

  As described above, as described in the cooperative transmission of the wireless device 3 in each of the transmission methods 1 to 4, during the cooperative transmission, the wireless device 2 and the wireless device 3 transmit wireless signals by the spatial multiplexing method or the same. Transmit wireless signals simultaneously. The wireless device 1 determines that the information frame has been successfully received regardless of whether the information frame is received from the wireless device 2 or the wireless device 3.

  By doing in this way, especially when the communication quality between the wireless device 1 and the wireless device 3 is better than the communication quality between the wireless device 1 and the wireless device 2, the wireless device 1 and the wireless device 2. The number of retransmissions of radio signals can be reduced, and throughput characteristics and delay characteristics can be improved, compared with the case where communication is performed only between and.

  In addition, even if the communication quality between the wireless device 1 and the wireless device 3 is good, the operation of the wireless device 2 is not an overhead of communication between the wireless device 1 and the wireless device 3, It is possible to realize throughput characteristics and delay characteristics comparable to those in the case where communication is performed only between the wireless device 1 and the wireless device 2.

  Furthermore, since the wireless device 1 and the wireless device 3 are physically separated, the communication path between the wireless device 1 and the wireless device 2 and the communication path between the wireless device 2 and the wireless device 3 are different. Because the correlation is small or uncorrelated, even if one of the channels is temporarily deteriorated, the other channels can make up for it and realize stable communication that is less susceptible to changes in the communication environment it can.

  Next, a method for discarding information frames temporarily stored by the wireless device 3 will be described.

  (First Discarding Method) Information about a period during which coordinated transmission is performed is added to the coordination request signal transmitted from the radio apparatus 2. The wireless device 3 receives the cooperation request signal from the wireless device 2 to grasp the period for performing the cooperative transmission.

  The wireless device 3 temporarily stores the frame specified by the cooperation identifier in the cooperation frame storage unit 60 during the period of the cooperative transmission. The wireless device 3 discards all frames temporarily stored in the cooperative frame storage unit 60 when the period for performing cooperative transmission elapses.

  By doing in this way, the radio | wireless apparatus 3 can carry out the cooperative transmission of the information frame temporarily memorize | stored at any time within the period which performs a cooperative transmission. However, when a period for performing cooperative transmission is set to be long, the wireless device 3 consumes a huge amount of memory resources.

  (Second Discarding Method) The radio apparatus 3 sequentially discards information frames that the radio apparatus 1 has successfully received from the information frames temporarily stored in the cooperative frame storage unit 60. Note that the wireless device 3 recognizes which information frame the wireless device 1 has successfully received from the delivery confirmation signal.

  In this way, it is possible to suppress the amount of memory resources used by the wireless device 3 while realizing cooperative transmission of information frames.

  (Third Discarding Method) First, the wireless device 1 describes in the delivery confirmation signal the minimum value (SSN: Starting Sequence Number) of the sequence numbers of information frames that need to be notified of successful delivery.

  Therefore, the wireless devices 2 and 3 can grasp that the wireless device 1 has successfully received the information frame corresponding to the sequence number smaller than the SSN by receiving the delivery confirmation signal in which the SSN is described.

  The wireless device 3 discards not only the information frame successfully received by the receiving device 1 but also the information frame whose sequence number is smaller than the SSN.

  In this way, the amount of memory resources used by the wireless device 3 can be more effectively suppressed while realizing cooperative transmission of information frames.

  (Fourth Discarding Method) Although the wireless apparatus 3 has cooperatively transmitted the information frame, the information frame once cooperatively transmitted should not be discarded in consideration of the fact that cooperative transmission of the information frame is required again. And

  However, when the number of times that an information frame is cooperatively transmitted exceeds a predetermined number of times (the upper limit number of cooperative transmissions), the wireless device 3 discards the information frame.

  This is because the communication environment (quality) between the wireless device 3 and the wireless device 1 is expected to deteriorate for some reason because transmission was not possible even after a predetermined number of retransmissions.

  Note that the upper limit number of cooperative transmissions may be determined by the wireless device 3 itself, or a value determined by the wireless device 2 may be added to a cooperation request signal or the like and notified to the wireless device 3.

  (Fifth Discarding Method) The wireless device 2 that is the transmission source of the cooperation request signal transmits to the wireless device 3 an end signal for ending the cooperative transmission of the wireless device 3. When receiving the end signal from the wireless device 2, the wireless device 3 discards the information frame stored in the cooperative frame storage unit 60.

  By doing in this way, the radio | wireless apparatus 2 which requested | required coordinated transmission can control whether the radio | wireless apparatus 3 performs coordinated transmission.

  In the above description, the wireless device 2 transmits the end signal, but the wireless device 1 may transmit the end signal. Further, the wireless device 1 may add information for ending the cooperative transmission of the wireless device 3 to the delivery confirmation signal and transmit the information to the wireless device 3.

  In this way, the wireless device 1 cooperates with the wireless device 3 based on the radio signal transmitted from the wireless device 2 and the wireless device 3 or the observation result of the communication status with the wireless device 2 and the wireless device 3. It is possible to control whether the transmission is continued or terminated.

  Furthermore, the wireless device 1 can transmit not only an end signal for terminating cooperative transmission of the wireless device 3, but also a signal for notifying a wireless device that newly requests cooperative transmission. At this time, the wireless device newly designated as the wireless device that requests cooperative transmission performs cooperative transmission, and the wireless device 3 that has been performing cooperative transmission ends the cooperative transmission.

  Next, a method in which the wireless device 2 selects a wireless device that requests cooperative transmission will be described. In the description so far, the wireless device 2 requests cooperative transmission from one wireless device 3 when transmitting a wireless signal to the wireless device 1.

  However, the wireless device 2 first needs to search for what kind of wireless device exists around. Next, it is necessary for the wireless device 2 to select which of the plurality of wireless devices existing in the vicinity is to request coordinated transmission.

  First, a method in which the wireless device 2 searches for what kind of wireless device exists in the surroundings will be described.

  (First Search Method) The wireless device 2 can grasp what kind of wireless device exists in the vicinity from the wireless signal transmitted from another wireless device. For example, the wireless device 2 can recognize that the wireless device that is the transmission source of the received wireless signal exists around the wireless device 2.

  (Second Search Method) The radio apparatus 2 broadcasts a search signal for searching for radio apparatuses existing in the vicinity. The wireless device that has received the search signal returns a response signal. In this way, the wireless device 2 can recognize that the wireless device that has returned a response signal to the search signal exists around the wireless device 2.

  The radio | wireless apparatus 2 may transmit a search signal by a non-directional radio wave. The wireless device 2 may transmit the search signal by a radio wave having directivity (directional beam) and sequentially switch the transmission direction of the directional beam.

  First, a case where the wireless device 2 transmits a search signal using an omnidirectional beam will be described.

  The wireless device 2 selects a wireless device that requests cooperative transmission (transmits a cooperative request signal) based on communication quality (for example, received power) when a response signal to the search signal is received.

  For example, it is assumed that the reception power of each response signal received by the wireless device 2 from the wireless devices A, B, and C is Ra> Rb> Rc (Ra: reception power of the response signal from the wireless device A, Rb: wireless) Received power of response signal from device B, Rc: Received power of response signal from wireless device C).

  When the wireless device 2 transmits a wireless signal to the wireless device C, the wireless device 2 selects at least one of the wireless devices A and B as a wireless device that requests cooperative transmission.

  However, in the above method, the wireless device 2 cannot grasp the communication quality between the wireless device A and the wireless device C and the communication quality between the wireless device B and the wireless device C.

  When transmitting a wireless signal from the wireless device 2 to the wireless device C, the wireless device C determines whether or not the wireless devices A and B are suitable as wireless devices that request coordinated transmission.

  The wireless device C actually receives the wireless signal that is cooperatively transmitted from the wireless devices A and B. The wireless device C is a wireless device that the wireless devices A and B request cooperative transmission according to the observation results of the communication quality between the wireless device A and the wireless device C and the communication quality between the wireless device B and the wireless device C. It is determined whether or not the device is appropriate.

  Specifically, the wireless device C receives the number of successful receptions and reception rates of wireless signals transmitted from the wireless device A by the spatial multiplexing method, and the number of successful receptions of wireless signals transmitted from the wireless device B by the spatial multiplexing method. Or the reception success rate is compared with a predetermined threshold (threshold).

  For example, when the number of successful receptions and reception success rates of wireless signals transmitted from the wireless device B by the spatial multiplexing method are smaller than a predetermined threshold, the wireless device C communicates with the communication quality between the wireless device B and the wireless device C. Wireless device C determines that wireless device B is not appropriate as a wireless device that requests coordinated transmission.

  Note that the threshold for the number of successful receptions is determined in consideration of the number of information frames that the wireless device C has requested for coordinated transmission using an acknowledgment signal.

  For example, when the number of information frames for which the wireless device C has requested cooperative transmission is 10, the threshold for the number of successful receptions is determined as “5”, and the number of information frames for which the wireless device C has requested cooperative transmission. Is one frame, the threshold for the number of successful receptions may be set to “1”. That is, the threshold for the number of successful receptions may be changed according to the number of information frames for which the wireless device C has requested cooperative transmission.

  As described above, when the wireless device C determines that the wireless device B is not suitable as a wireless device that requests cooperative transmission, the wireless devices A and B are wireless devices for which cooperative transmission is requested by the wireless device 2. In addition, a signal for terminating the cooperative transmission is transmitted to the wireless device B.

  Note that the wireless device C may directly transmit the signal for terminating the cooperative transmission to the wireless device B. Further, the wireless device C transmits a signal notifying that the wireless device B is not appropriate as a wireless device requesting cooperative transmission to the wireless device 2, and transmits a signal for the wireless device 2 to end the cooperative transmission. It is also possible to send to.

  Also, the wireless device C transmits the search signal in advance and receives response signals from the wireless devices A and B, so that the communication quality between the wireless device A and the wireless device C and the wireless device B And the wireless device C can grasp the communication quality and notify the wireless device 2 of the information.

  In this way, the wireless device 2 has not only the communication quality between the wireless device 2 and the other wireless device, but also the communication quality between the wireless device C that is the destination of the wireless signal and the other wireless device. I can grasp it. Therefore, since the wireless device 2 can grasp not only the communication environment around the local station but also the communication environment around the wireless device C, the wireless device 2 transmits a radio signal to the wireless device C in consideration of both communication environments. In this case, it is possible to select a wireless device that requires cooperative transmission.

  Next, a case where the wireless device 2 transmits a search signal using a directional beam will be described.

  The wireless device 2 transmits a search signal in a specific direction with a directional beam, and estimates the direction in which the received response signal arrives, thereby communicating with the wireless device that has returned the response signal and the communication partner (the wireless signal). It is possible to grasp the approximate positional relationship with the wireless device C that is the destination.

  FIG. 13 is a diagram illustrating an example of a result of the wireless device 3 grasping an approximate positional relationship between the wireless devices A and B that have returned a response signal and the wireless device C that is a communication partner.

  In the wireless device 2, the direction in which the response signal from the wireless device C arrives is almost the same as the direction in which the response signal from the wireless device A arrives, and the wireless device 2 is more wireless than the received power of the response signal from the wireless device C. Assume that the received power of the response signal from apparatus A is large.

  Further, the direction in which the response signal from the wireless device C arrives is opposite to the direction in which the response signal from the wireless device B arrives, and the wireless device is more than the received power of the response signal from the wireless device C. Assume that the reception power of the response signal from B is large.

  When the response signals transmitted from the wireless devices A, B, and C are as described above, the wireless device 2 can estimate the positional relationship between the wireless devices 2, A, B, and C as shown in FIG.

  The wireless device 2 is a wireless device that requests wireless device A for cooperative transmission when wireless device C is a communication partner and the positional relationship of wireless devices 2, A, B, and C is estimated as shown in FIG. Choose as. That is, the wireless device 2 selects a wireless device that requests cooperative transmission according to the positional relationship between the wireless device C of the communication partner, the other wireless devices A and B, and the own wireless device 2.

  Note that the wireless device 2 selects a wireless device that requests cooperative transmission according to the positional relationship between the wireless devices A, B, C, and 2, and the wireless device C has successfully received wireless signals received from the wireless devices A and B. A method of selecting a wireless device that requests cooperative transmission according to the number (or reception success rate) can be used in combination.

  In the above description, a case has been described in which the relationship between the wireless device to which the wireless device 2 transmits the cooperation request signal and the wireless device that actually performs the cooperative transmission is associated with the one-to-one relationship.

  However, the wireless device according to the first embodiment is not limited to the above, and the wireless device 2 selects, as needed, a wireless device that actually performs cooperative transmission from a plurality of wireless devices that transmit the cooperative request signal. be able to.

  Specifically, the wireless device C observes the communication quality (the number of successful receptions or the reception success rate) of the wireless signals received from the wireless devices A and B, and thereby, among the plurality of wireless devices that have received the cooperation request signal. Thus, a radio apparatus that actually performs cooperative transmission is selected as needed.

  For example, the wireless device C adds the identifier of the wireless device that actually performs cooperative transmission to the delivery confirmation signal that is returned to the wireless device 2. When the wireless devices A and B have already received the cooperation request signal from the wireless device 2, the wireless device C adds the identifier of the wireless device A to the delivery confirmation signal. At this time, the wireless device A performs cooperative transmission after receiving the delivery confirmation signal. On the other hand, the wireless device B temporarily stores the frame transmitted by the wireless device C, but does not perform cooperative transmission.

  As described above, the wireless device C requests cooperative transmission from the wireless device A or the wireless device B according to the communication quality of the wireless signals received from the wireless devices A and B, thereby causing the optimal wireless device to perform cooperative transmission. be able to.

  In the above method, the wireless device 2 transmits a cooperation request signal to more wireless devices than the number of wireless devices that can transmit wireless signals to the wireless device C by the spatial multiplexing method (multiplexing number). This can be achieved.

  The wireless device 2 can also set a broadcast address instead of a specific wireless device address as the destination address of the cooperation request signal. In this case, all the wireless devices that have received the cooperation request signal from the wireless device 2 temporarily store the frame transmitted from the wireless device 2. The wireless device C selects a wireless device that actually performs cooperative transmission among all the wireless devices that have received the cooperation request signal from the wireless device 2.

  By doing in this way, the wireless device C can cooperate with the wireless device C without performing a process of determining which of the wireless devices existing around the wireless device 2 is to transmit the cooperation request signal. Depending on the communication quality of the transmitted radio signal, the optimal radio apparatus can perform coordinated transmission.

  Next, when the wireless device 2 transmits a wireless signal to the wireless device C, a case will be described in which the number of wireless devices that are suitable as wireless devices performing cooperative transmission is very large. For example, wireless devices A, B, D, and E exist between the wireless device 2 and the wireless device C, and all of the wireless signals that are cooperatively transmitted from the wireless devices A, B, D, and E are stored in the wireless device C. Assume that communication quality is high.

  In this case, although the wireless devices A, B, D, and E are suitable as wireless devices that perform coordinated transmission, when the wireless device 2 transmits a wireless signal to the wireless device C, the wireless devices A, B, D, and E It is not necessary for all of the wireless devices A, B, D, and E to temporarily store the wireless signals transmitted from the wireless device 2.

  When the wireless device C has a predetermined number or more of wireless devices having sufficient characteristics (communication quality) as a wireless device requesting cooperative transmission, the wireless device C terminates cooperative transmission with respect to some of the wireless devices. To be notified.

  In this way, it is possible to release resources of the wireless device that temporarily stores the wireless signal transmitted from the wireless device 2 for cooperative transmission.

  Thus, according to the wireless device 3 (wireless devices A and B) according to the first embodiment, even when the communication environment from the wireless device 2 to the wireless device 1 (wireless device C) deteriorates, Since the wireless device 3 (wireless devices A and B) performs transmission (cooperative transmission) of wireless signals that the wireless device 1 (wireless device C) has failed to receive, it is possible to suppress a decrease in throughput.

  In the wireless device 3 (wireless devices A and B) according to the first embodiment, the communication environment from the wireless device 2 to the wireless device 1 (wireless device C) is improved, and the wireless device 1 (wireless device C) is When the reception of the radio signal no longer fails, the radio signal transmitted from the radio device 2 is only temporarily stored, and overhead is generated when communicating from the radio device 2 to the radio device 1 (radio device C). Therefore, throughput can be improved promptly.

  In the above description of the first embodiment, the wireless device 2 has been described as transmitting a cooperation request signal. However, the wireless device 1 (wireless device C) can transmit the cooperation request signal.

  The cooperation request signal transmitted by the wireless device 1 (wireless device C) is as described above.

  The wireless device 1 (wireless device C) can transmit a cooperation request signal to the wireless device 3 in advance before the wireless device 2 starts transmitting a wireless signal.

  The wireless device 1 (wireless device C) can transmit a cooperation request signal to the wireless device 3 when the communication quality of the wireless signal transmitted from the wireless device 2 is less than a predetermined value.

  However, since it is difficult for the wireless device 1 to accurately predict the timing at which the wireless device 2 transmits the wireless signal, the wireless device 2 may transmit the cooperation request signal regardless of the timing at which the wireless device 2 transmits the wireless signal. good.

  For example, a wireless device 2 is mounted on an HDD recorder, a wireless device 1 (wireless device C) is fixed to the left end of a large TV, and a wireless device 3 (wireless devices A and B) is fixed to the right end of the large TV. Suppose that

The HDD recorder transmits media information such as moving images and sounds stored in the built-in storage unit to the large TV via the wireless device 2. In this case, the HDD recorder uses the wireless device 2 as a destination to the wireless device 1 (wireless device C) and requests cooperative transmission from the wireless device 3 (wireless devices A and B). At this time, the wireless device 3 (wireless devices A and B) may be set in advance to always perform cooperative transmission. By doing so, communication from the wireless device 2 to the wireless device 1 (wireless device C) is possible. Even when the quality deteriorates, if the communication quality from the wireless device 2 to the wireless device 3 (wireless devices A and B) is good, the throughput of the media information transmission from the HDD recorder to the large TV is reduced. The decrease can be suppressed.

  In addition, this radio | wireless apparatus 3 (radio | wireless apparatus A, B) is realizable also by using a general purpose computer apparatus as basic hardware, for example. That is, the reception unit 10, the transmission unit 20, the control unit 30, and the cooperation management unit 40 can be realized by causing a processor mounted on the computer device to execute a program. At this time, the wireless device 3 may be realized by installing the above program in a computer device in advance, or may be stored in a storage medium such as a CD-ROM or distributed through the network. Thus, this program may be realized by appropriately installing it in a computer device. Further, the identifier storage unit 50 and the cooperative frame storage unit 60 include a memory, a hard disk or a storage medium such as a CD-R, a CD-RW, a DVD-RAM, a DVD-R, or the like built in or externally attached to the computer device. It can be realized by appropriately using.

(Second Embodiment)
In the second embodiment, a network in which a wireless device that has received a signal for permitting transmission of a wireless signal (hereinafter referred to as a polling signal) can acquire the transmission right of the wireless signal and transmit the wireless signal will be described.

  FIG. 14 is a diagram illustrating a positional relationship between the wireless devices 1, 2, 3_1, and 3_2 according to the second embodiment. The configuration of the wireless devices 3_1 and 3_2 according to the second embodiment is the same as that of the wireless device 3 according to the first embodiment. The configuration of the wireless devices 1 and 2 according to the second embodiment is the same as that of the wireless devices 1 and 2 according to the first embodiment.

  FIG. 15 is a diagram illustrating frames transmitted and received by the wireless devices 1, 2, 3_1, and 3_2 when the wireless devices 3_1 and 3_2 perform coordinated transmission.

  First, the wireless device 1 transmits a polling signal. Information similar to the information included in the cooperation request signal described in the first embodiment is added to the polling signal. The polling signal is received not only by the wireless device 2 but also by the wireless devices 3_1 and 3_2.

  The wireless device 1 transmits a polling signal every time communication with the wireless device 2 is started. Even if the wireless device 2 continues to communicate with wireless devices other than the wireless device 1, when the wireless device 1 starts communication with the wireless device 2, a polling signal is transmitted.

  Next, when the wireless device 2 receives the polling signal from the wireless device 1, the wireless device 2 transmits a plurality of information frames to the wireless device 1 on the assumption that the wireless signal transmission right is given to the wireless device 1. The plurality of information frames transmitted from the wireless device 2 are received not only by the wireless device 1 but also by the wireless devices 3_1 and 3_2.

  Next, the wireless device 1 returns a delivery confirmation signal (Block Ack) to the wireless device 2. The delivery confirmation signal is received not only by the wireless device 2 but also by the wireless devices 3_1 and 3_2. Information (spatial multiplexing information) necessary when the radio apparatus 2 and the radio apparatuses 3_1 and 3_2 that have received the delivery confirmation signal transmit radio signals by the spatial multiplexing method is added to the delivery confirmation signal.

  Next, according to the acknowledgment signal (including spatial multiplexing information) returned from the wireless device 1, the wireless device 2 retransmits the information frame, and the wireless devices 3_1 and 3_2 perform coordinated transmission of the wireless signal.

  As described above, the wireless devices 3_1 and 3_2 perform cooperative transmission.

  Next, four methods in which the radio apparatuses 3_1 and 3_2 end cooperative transmission of radio signals will be described.

  (First Termination Method) NAV (Network Allocation Vector) (wireless channel can be used exclusively) set or extended continuously by radio signals transmitted and received between the radio device 2 and the radio device 1 When the (period) is interrupted, the wireless devices 3_1 and 3_2 end cooperative transmission.

  (Second Termination Method) The period for performing coordinated transmission is described in the polling signal, and after the radio devices 3_1 and 3_2 have received the polling signal, the period for performing coordinated transmission described in the polling signal has elapsed Sometimes, cooperative transmission ends.

  (Third Termination Method) The wireless devices 3_1 and 3_2 terminate the cooperative transmission when receiving the next polling signal after the communication is started with the polling signal as a trigger.

  (Fourth End Method) The wireless devices 3_1 and 3_2 end cooperative transmission when communication is started with a polling signal as a trigger and then a polling signal that does not include the own wireless device as a destination is received. .

  Note that in the second embodiment, the method for terminating cooperative transmission is not limited to the above four methods, and the above four methods or other methods can be combined.

  When terminating the cooperative transmission, the wireless devices 3_1 and 3_2 delete the frame temporarily stored in the cooperative frame storage unit 60.

  The wireless devices 3_1 and 3_2 do not temporarily store a frame that needs to be temporarily stored until the polling signal is received again after completing cooperative transmission once.

  When the wireless device 3 once ends cooperative transmission and receives a polling signal again, the wireless device 3 starts processing for cooperative transmission again.

  In the above, the wireless device 1 not only transmits a polling signal (requests cooperative transmission) but also transmits a delivery confirmation signal (designates a wireless device that actually performs cooperative transmission).

  By doing in this way, the radio | wireless apparatus 1 can grasp | ascertain directly the communication quality of the radio signal cooperatively transmitted from radio | wireless apparatus 3_1 and 3_2, and can select appropriately the radio | wireless apparatus which actually performs cooperative transmission.

  That is, using the information about the communication quality of the radio signal that is cooperatively transmitted from the wireless devices 3_1 and 3_2, it is possible to select a wireless device that requests cooperative transmission next. For this reason, the wireless device 1 transmits the cooperation request signal, and sets the number of wireless devices that must temporarily store wireless signals for cooperative transmission to an optimal number without increasing the number more than necessary. be able to.

(Third embodiment)
In 1st Embodiment and 2nd Embodiment, when the radio | wireless apparatus 2 transmitted a radio signal with respect to the radio | wireless apparatus 1, the example which the radio | wireless apparatus 3 carries out cooperative transmission of the radio signal was shown.

  In the third embodiment, when the wireless device 2 transmits a wireless signal to the wireless device 1, the wireless signal 3 receives the wireless signal in cooperation with the wireless device 1.

  FIG. 16 is a diagram illustrating a configuration of a network according to the third embodiment.

  The network according to the third embodiment includes a wireless device 1, a wireless device 2, and a wireless device 3. The wireless device 1 and the wireless device 3 receive a wireless signal transmitted from the wireless device 2 in cooperation with each other.

  The wireless device 2 and the wireless device 1 communicate by transmitting and receiving wireless signals. The wireless device 2 and the wireless device 3 communicate by transmitting and receiving wireless signals. The wireless device 1 and the wireless device 3 communicate with each other using a communication method that is uncorrelated with a communication method used between the wireless devices 1-2 or 2-3 (hereinafter, a specific communication method).

  An example of the specific communication method may be wired communication or wireless communication using a frequency channel that is not used between the wireless devices 1-2 and 2-3.

  The wireless device 1 operates as a main receiving device. The wireless device 3 operates as a slave receiving device. The wireless device 3 receives the information frame transmitted from the wireless device 2 in cooperation with the wireless device 1. That is, the wireless device 3 receives the information frame transmitted from the wireless device 2 to the wireless device 1, and transfers the received information frame to the wireless device 1 by a specific communication method.

  As described above, the wireless device 3 receives the information frame in cooperation with the wireless device 1, so that the wireless device 1 includes at least one of the wireless device 1 and the wireless device 3 among the information frames transmitted from the wireless device 2. Thus, the information frame that has been successfully received is successfully received.

  FIG. 17 is a diagram illustrating radio signals transmitted and received by the radio apparatuses 1, 2, and 3 when the radio apparatus 3 receives information frames in a coordinated manner.

  First, the wireless device 1 transmits to the wireless device 2 a signal (hereinafter not shown) for notifying that the wireless device 3 is a wireless device that performs reception processing in cooperation (not shown). . Note that the wireless device 1 transmits the notification signal in advance before the wireless signal is transmitted from the wireless device 2. Moreover, when transmitting a radio signal from the wireless device 2 to the wireless device 1, the wireless device 2 may store in advance that the wireless device 3 performs reception processing in cooperation. In this way, when the wireless device 2 transmits a wireless signal to the wireless device 1, the wireless device 2 grasps that the wireless device 3 performs reception processing in cooperation.

  Next, the wireless device 2 transmits a plurality of information frames to the wireless device 1 and the wireless device 3. When transmitting a plurality of information frames, the wireless device 2 adds spatial multiplexing information to a wireless signal to be transmitted. This spatial multiplexing information has been described in the first embodiment, and is information necessary for the wireless device 1 and the wireless device 3 to transmit a wireless signal to the wireless device 2 by the spatial multiplexing method. Note that the wireless device 2 may use any of the transmission methods 1 to 4 described in the first embodiment.

  Next, the wireless device 1 and the wireless device 3 return a delivery confirmation signal (BLOCK ACK) for notifying the successfully received information frame to the wireless device 2 by the spatial multiplexing method. Note that the transmission source address of the delivery confirmation signal returned by the wireless device 3 may be the terminal identifier (for example, the MAC address) of the wireless device 3 or the terminal identifier of the wireless device 1, and is designated by the notification signal. It may be a specific identifier.

  Next, the wireless device 2 receives a delivery confirmation signal from the wireless device and the wireless device 3.

  Next, the wireless device 2 determines that the information frame successfully received by at least one of the wireless device 1 and the wireless device 3 has been successfully delivered to the wireless device 1.

  For example, it is assumed that the wireless device 2 has transmitted five information frames (sequence numbers: SN = 1, 2, 3, 4, 5). At this time, the result of the delivery confirmation signal from the wireless device 1 is “SN1 = OK, SN2 = NG, SN3 = NG, SN4 = OK, SN5 = OK”, and the result of the delivery confirmation signal from the wireless device 3 is It is assumed that “SN1 = OK, SN2 = OK, SN3 = OK, SN4 = OK, SN5 = NG”.

  That is, the wireless device 3 has successfully received the information frames of SN = 2 and 3 that the wireless device 1 has failed to receive. The wireless device 1 has successfully received the SN = 5 information frame that the wireless device 3 has failed to receive.

  In this case, the wireless device 2 has successfully received at least one of the wireless device 1 and the wireless device 3 with respect to all five frames of SN = 1 to 5, so that the delivery to the wireless device 1 was successful. Is determined.

  According to this determination result, the wireless device 2 next transmits an information frame of the next sequence number (SN = 6 to 10) without retransmitting the information frame of SN = 1 to 5.

  As described above, according to the wireless device according to the third embodiment, the wireless device 3 receives the wireless signal transmitted from the wireless device 2 to the wireless device 1 and transmits the wireless signal successfully received to the wireless device 1. By transferring (coordinate reception of the wireless device 3), the number of retransmissions of the wireless device 2 can be reduced, and the wireless device 1 and the wireless device 3 return a delivery confirmation signal to the wireless device 2 by a spatial multiplexing method. Since the overhead generated when the wireless device 3 performs cooperative reception can be reduced, throughput characteristics and delay characteristics between the wireless device 1 and the wireless device 2 can be improved.

  In the third embodiment, after the wireless device 3 receives the wireless signal from the wireless device 2, the time required to transfer the wireless signal to the wireless device 1 (specification between the wireless device 1 and the wireless device 3) The description has been given assuming that the processing delay due to the communication method is sufficiently small.

  However, even when the processing delay due to the specific communication method between the wireless device 1 and the wireless device 3 is large, cooperative reception of the wireless device 3 can be performed.

  For example, it is assumed that the wireless device 2 has transmitted five information frames (sequence numbers: SN = 1, 2, 3, 4, 5). At this time, the result of the delivery confirmation signal from the wireless device 1 is “SN1 = OK, SN2 = NG, SN3 = NG, SN4 = OK, SN5 = OK”, and the result of the delivery confirmation signal from the wireless device 3 is It is assumed that “SN1 = OK, SN2 = OK, SN3 = OK, SN4 = OK, SN5 = NG”.

  In this case, the wireless device 2 has successfully received at least one of the wireless device 1 and the wireless device 3 with respect to all five information frames with SN = 1 to 5, so that the delivery to the wireless device 1 was successful. It is determined that

  According to this determination result, the wireless device 2 next transmits an information frame of the next sequence number (SN = 6 to 10) without retransmitting the information frame of SN = 1 to 5.

  Here, the processing delay due to the specific communication method between the wireless device 1 and the wireless device 3 is large, and before the wireless device 3 transfers the wireless signal to the wireless device 1, the wireless device 1 receives the next sequence number (SN = 6-10) is received from the wireless device 2.

  In this case, the wireless device 1 receives the information frames of SN = 6 to 10 even though the information frames of SN = 2 and 3 have not been received yet. Therefore, the wireless device 1 may return a delivery confirmation signal requesting retransmission of information frames with SN = 2 and 3 to the wireless device 2.

  Here, the wireless device 2 has received a delivery confirmation signal for requesting retransmission of information frames with SN = 2, 3 from the wireless device 1, and SN = 2, 3 according to the delivery confirmation signal from the wireless device 2. If it is determined that the information frame has been successfully delivered, the retransmission request for the information frame with SN = 2 and 3 is ignored.

  Then, the wireless device 2 retransmits information frames other than information frames with SN = 2 and 3, for example, information frames with SN = 6 to 10 and transmits information frames with SN 11 or more.

  By doing in this way, even when the processing delay due to the specific communication method between the wireless device 1 and the wireless device 3 is large, the wireless device 3 performs cooperative reception, and between the wireless device 1 and the wireless device 2 Throughput characteristics and delay characteristics can be improved.

  Next, a case where a processing delay due to a specific communication method between the wireless device 1 and the wireless device 3 becomes a long time due to some cause will be described.

  In the above example, it is assumed that the wireless device 1 or the wireless device 3 has successfully received all the information frames of SN = 6 to 10 transmitted by the wireless device 2.

  For example, the result of the delivery confirmation signal from the wireless device 1 is “SN6 = NG, SN7 = NG, SN8 = NG, SN9 = NG, SN10 = OK”, and the result of the delivery confirmation signal from the wireless device 3 is “ It is assumed that SN6 = OK, SN7 = OK, SN8 = OK, SN9 = OK, SN10 = NG ”.

  Then, it is assumed that the wireless device 2 newly transmits information frames with SN = 11-15.

  If no information frame is transferred from the wireless device 3 to the wireless device 1, the wireless device 1 determines that the information frame of SN = 2, 3, 6, 7, 8, 9 has not been received yet. .

  Here, it is assumed that the delivery confirmation information field (bitmap) of the delivery confirmation signal has a restriction that, for example, only success or failure of reception of five consecutive information frames of SN can be described.

  Under such a restriction, the wireless device 1 is a delivery requesting retransmission of information frames of SN = 2, 3, 4, 5, 6 in ascending order of SN among information frames determined to have not been received yet. Send a confirmation signal.

  On the other hand, the wireless device 2 has already been determined that the delivery of information frames with SN = 1 to 10 has been successful. In order for the wireless device 2 to transmit a new information frame, information about whether or not the information frame of SN = 11 to 16 has been successfully delivered is necessary.

  At this time, since the wireless device 1 continues to transmit a delivery confirmation signal requesting retransmission of information frames of SN = 2, 3, 4, 5, 6, the wireless device 2 is not able to transmit information frames of SN = 11-15. There may be situations where it is not possible to know whether or not it was successful.

  Further, for example, it is assumed that there is a restriction that only five sequence numbers of information frames requesting retransmission can be described in the delivery confirmation information field of the delivery confirmation signal.

  Even under such restrictions, in the above example, the wireless device 1 continues to transmit a delivery confirmation signal requesting retransmission of information frames with SN = 2, 3, 6, 7, and 8, and the wireless device 2 has SN = A situation may occur in which it is not possible to know whether or not the information frames 11 to 15 have been successfully delivered.

  If the wireless device 2 falls into the situation as described above, the wireless device 2 may determine that the information frames having SN = 1 to 10 have been successfully delivered, and newly transmit the information frames having SN = 11 to 15 , It is not possible to determine whether or not the information frames of SN = 11 to 15 have been successfully delivered.

  In order to solve such a problem, the wireless device 2 adds information on a minimum sequence number (SSN: Start Sequence Number) that needs to be acknowledged to a wireless signal (information frame) to be transmitted.

  Thus, in the previous example, when the wireless device 2 transmits an information frame with SN = 6 to 10, SSN “6” is added, so that the wireless device 1 has an information frame with an SN of less than “6”. Therefore, it can be determined that it is not necessary to request retransmission (it is not necessary to notify the wireless device 2 by the delivery confirmation signal whether the wireless device 1 has been successfully received).

  That is, the wireless device 1 does not need to request retransmission of information frames of SN = 2 and 3 (it is not necessary to notify the wireless device 2 of whether the wireless device 1 has been successfully received by a delivery confirmation signal). judge. The wireless device 3 determines that it is not necessary to request retransmission of the information frame of SN = 5 (it is not necessary to notify the wireless device 2 of whether or not the wireless device 1 has been successfully received by a delivery confirmation signal).

  The wireless device 2 adds an SSN when transmitting the information frame, thereby determining which wireless signal in the information frame transmitted by the wireless device 2 needs to be returned with a delivery confirmation signal. Can be notified.

  The method for adding the SSN to the radio signal transmitted by the wireless device 2 may be any method as long as it can be notified to the wireless device 1, and a field for explicitly notifying the SSN. May be newly provided, and an arrangement may be made wherein the minimum sequence number of the information frame included in the wireless signal transmitted by the wireless device 2 is SSN.

In the method of newly providing a field for notifying the SSN explicitly, a new field for notifying the SSN is required for the radio signal, but a delivery confirmation signal is requested regardless of the SN of the information frame to be transmitted. be able to,
In the method of determining that the minimum sequence number of the information frame included in the wireless signal transmitted by the wireless device 2 is SSN, the SN of the information frame requesting the delivery confirmation signal and the SN of the information frame to be transmitted are linked. However, it is possible to reduce the overhead because there is no need to provide a field for notifying the wireless signal of the SSN.

  The wireless device 2 may determine the communication quality of the wireless devices 1 and 3 from the delivery confirmation signal received from the wireless devices 1 and 3 and change the transmission destination of the wireless signal.

  For example, the wireless device 2 may transmit a wireless signal only to the wireless device 1 when the communication quality of the wireless device 1 is equal to or higher than the threshold value and the communication quality of the wireless device 3 is lower than the threshold value.

  In addition, for example, the wireless device 2 may transmit a wireless signal only to the wireless device 1 when the communication quality of the wireless devices 1 and 3 is equal to or higher than a threshold value.

  Furthermore, for example, when the communication quality of the wireless devices 1 and 3 is less than the threshold value, the wireless device 2 transmits a wireless signal to both the wireless device 1 and the wireless device 3.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

The figure which shows the network which concerns on the 1st Embodiment of this invention. The figure which shows the radio signal transmitted / received by the transmission system 1. FIG. The figure which shows the radio signal transmitted / received by the transmission system 2. FIG. The figure which shows the radio signal transmitted / received by the transmission system 3. FIG. The figure which shows the radio signal transmitted / received by the transmission system 4. 1 is a block diagram showing a configuration of a wireless device according to a first embodiment of the present invention. The flowchart which shows the operation | movement of the 1st Embodiment of this invention. The figure which shows the cooperative transmission in the transmission system 1. FIG. The figure which shows the cooperative transmission in the transmission system 1. FIG. The figure which shows the cooperative transmission in the transmission system 2. FIG. The figure which shows the cooperative transmission in the transmission system 4. FIG. The figure which shows the cooperative transmission in the transmission system 4. FIG. The figure which shows the positional relationship of the surrounding radio | wireless apparatus. The figure which shows the network which concerns on the 2nd Embodiment of this invention. The figure which shows the cooperative transmission in 2nd Embodiment. The figure which shows the network which concerns on the 3rd Embodiment of this invention. The figure which shows cooperative reception.

Explanation of symbols

1, 2, 3, A, B, C ... wireless device 10 ... receiving unit 20 ... transmitting unit 30 ... control unit 40 ... cooperative management unit 50 ... identifier storage unit 60 ..Collaborative frame storage unit

Claims (14)

A wireless device that relays a wireless signal,
First storage means for storing identification information for identifying whether there is a possibility of relaying a wireless signal from another wireless device;
Receiving means for receiving a first radio signal having the first radio apparatus as a transmission source and the second radio apparatus as a destination;
Determining means for determining whether or not the first wireless signal is a wireless signal that may be relayed according to the identification information;
Second storage means for temporarily storing the first radio signal when the determination means determines that there is a possibility of relaying the first radio signal;
Of the wireless signals temporarily stored in the second storage means when the second wireless device receives a delivery confirmation signal for notifying the wireless signal successfully received by the second wireless device, Transmission means for transmitting to the second wireless device a second wireless signal that is not notified of successful delivery to the second wireless device by a delivery confirmation signal;
A period in which the transmission means transmits the second radio signal in accordance with the delivery confirmation signal overlaps a period in which the first radio apparatus retransmits the third radio signal in accordance with the delivery confirmation signal ,
The second radio signal transmitted from the transmission means of the own radio apparatus according to the delivery confirmation signal and the third radio signal retransmitted from the first radio apparatus according to the delivery confirmation signal are spatially multiplexed by the spatial multiplexing method. Transmitted to the second wireless device,
The acknowledgment signal received from the second wireless device includes spatial multiplexing information for transmission to the second wireless device by a spatial multiplexing method,
The delivery confirmation signal is received not only by the own wireless device but also by the first wireless device,
The transmission unit is a radio apparatus that transmits the second radio signal to the second radio apparatus according to the spatial multiplexing method in accordance with the spatial multiplexing information . A wireless device that relays a wireless signal including a plurality of frames ,
First storage means for storing identification information for identifying whether there is a possibility of relaying a wireless signal from another wireless device;
Receiving means for receiving a first radio signal having the first radio apparatus as a transmission source and the second radio apparatus as a destination;
Determining means for determining whether or not the first wireless signal is a wireless signal that may be relayed according to the identification information;
Second storage means for temporarily storing a plurality of frames included in the first wireless signal when the determination means determines that there is a possibility of relaying the first wireless signal;
Of the frames temporarily stored in the second storage means when the second wireless device receives a delivery confirmation signal for notifying the wireless signal successfully received by the second wireless device, the delivery Transmission means for transmitting to the second wireless device that is not notified of successful delivery to the second wireless device by a confirmation signal;
A period in which the transmission unit transmits the second radio signal in accordance with the delivery confirmation signal overlaps a period in which the first radio apparatus retransmits the third radio signal ,
The second radio signal transmitted from the transmission unit according to the delivery confirmation signal and the third radio signal retransmitted from the first radio apparatus are transmitted to the second radio apparatus by spatial multiplexing. apparatus. A wireless device that relays a wireless signal including a plurality of frames,
It said second storage means, the first of the plurality of frames included in the radio signal, the radio apparatus according to claim 1 or claim 2, characterized in that for temporarily storing a frame in which no error is detected. The reception means receives a relay request signal for requesting relay of a radio signal having the first radio device as a transmission source and the second radio device as a destination from the first radio device or the second radio device,
The determination means according to claim 1 to claim 3, characterized in that determining the radio signal to the the source of the first wireless device and the second wireless device destination, a radio signal that can be relayed The wireless device according to any one of the above. The relay request signal is transmitted from the first wireless device to not only its own wireless device but also other wireless devices,
Among the plurality of wireless devices that have received the relay request signal, the delivery confirmation signal is transmitted from the second wireless device to some wireless devices including the own wireless device,
The wireless device according to claim 4 , wherein the second wireless signal is transmitted from the wireless device that has received the delivery confirmation signal to the second wireless device. A wireless device that relays a wireless signal including a plurality of frames ,
Receiving means for receiving a permission signal for allowing the first wireless device to transmit a wireless signal, which is a signal transmitted from the second wireless device to the first wireless device and the own wireless device;
A wireless signal transmitted from the first wireless device that is permitted to transmit a wireless signal by the permission signal to the second wireless device that is a transmission source of the permission signal is determined as a wireless signal that may be relayed. Determination means to perform,
Second storage means for temporarily storing a plurality of frames included in the first radio signal when the determination means determines that there is a possibility of relaying the first radio signal newly received by the reception means; ,
From the second wireless device, when receiving the acknowledgment signal for notifying the radio signal by the second wireless device is successfully received, among the frames that are temporarily stored in the second storage means, before Symbol Transmission means for transmitting, as a second wireless signal, a frame to which the successful delivery to the second wireless device is not notified by a delivery confirmation signal to the second wireless device;
A period in which the transmission unit transmits the second radio signal in accordance with the delivery confirmation signal overlaps a period in which the first radio apparatus retransmits the third radio signal,
It said second radio signal transmitted by said transmitting means from the radio device, and the third radio signal sent re et whether the first wireless device is transmitted to the second wireless device by spatial multiplexing scheme A wireless device characterized by the above. When a delivery confirmation signal is received from the second wireless device, the wireless signal is notified of successful delivery to the second wireless device by the delivery confirmation signal, and is temporarily stored in the second storage means The radio apparatus according to any one of claims 1 to 6, wherein a radio signal is deleted. A plurality of wireless signals are transmitted from the first wireless device to the second wireless device;
When all of the plurality of radio signals from the first radio device to the second radio device are successfully delivered to the second radio device;
Said receiving means from said second wireless device, any one of claims 1 to 7, characterized in that to relay radio signals to receive the acknowledgment signal which is described to be unnecessary A wireless device according to 1. A radio device that directly receives a radio signal from another radio device and also receives a radio signal relayed by a relay device,
A transmission means for transmitting a permission signal for requesting relay to the relay device, the permission signal permitting transmission of the wireless signal to the first wireless device, to the first wireless device and the relay device;
First receiving means for receiving a wireless signal from the first wireless device;
A reply means for returning a delivery confirmation signal indicating a radio signal successfully received to the first radio device;
Second receiving means for receiving, from the relay device as well as the first wireless device, a wireless signal which is not indicated as being successfully received in the delivery confirmation signal among the wireless signals transmitted from the first wireless device; With
In the delivery confirmation signal, the first wireless device and the relay device describe spatial multiplexing information for transmitting a wireless signal to the own wireless device by a spatial multiplexing method,
Of the radio signals transmitted from the first radio apparatus, radio signals not indicated as being successfully received in the delivery confirmation signal are spatially transmitted by the first radio apparatus and the relay apparatus specified in the spatial multiplexing information. A wireless device transmitted by a multiplexing method. The transmission means transmits the permission signal to a plurality of relay devices,
The second receiving unit transmits not only the first wireless device but also the plurality of relay devices for a wireless signal that is not indicated as being successfully received in the delivery confirmation signal among the wireless signals transmitted from the first wireless device. Also received from
From the radio signals received from each of the plurality of relay devices, the communication quality of each of the plurality of relay devices is measured,
The radio apparatus according to claim 9 , wherein a relay apparatus that is a destination of the permission signal is changed according to the communication quality. Among the plurality of relay devices, when the number of relay apparatus communication quality exceeds the threshold value exceeds a predetermined number, according to claim 10, characterized in that the number of the relay apparatus as a destination of the permission signal is reduced Wireless device. The transmission means transmits the permission signal to a plurality of relay devices,
The second receiving unit transmits not only the first wireless device but also the plurality of relay devices for a wireless signal that is not indicated as being successfully received in the delivery confirmation signal among the wireless signals transmitted from the first wireless device. Also received from
From the radio signals received from each of the plurality of relay devices, the communication quality of each of the plurality of relay devices is measured,
The radio apparatus according to claim 9 , wherein a relay apparatus specified by the spatial multiplexing information is changed according to the communication quality. Among the plurality of relay devices, when the number of relay apparatus communication quality exceeds the threshold value exceeds a predetermined number, according to claim 12, characterized in that the number of relay devices designated by the spatial multiplexing information is reduced Wireless devices. A control program for a wireless device that relays a wireless signal,
On the computer,
A function of writing identification information for identifying whether or not there is a possibility of relaying a radio signal from another radio device to the first storage means;
A function of receiving a first wireless signal having a first wireless device as a transmission source and a second wireless device as a destination;
A function of determining whether the first wireless signal is a wireless signal that may be relayed according to the identification information;
A function of temporarily storing the first radio signal in the second storage means when the determination means determines that there is a possibility of relaying the first radio signal;
Of the wireless signals temporarily stored in the second storage means when the second wireless device receives a delivery confirmation signal for notifying the wireless signal successfully received by the second wireless device, Realizing a function of transmitting a second wireless signal to the second wireless device that is not notified of successful delivery to the second wireless device by a delivery confirmation signal,
A period during which the second radio signal is transmitted according to the delivery confirmation signal overlaps with a period during which the first radio apparatus retransmits the third radio signal according to the delivery confirmation signal ,
The second radio signal transmitted from the transmission means of the own radio apparatus according to the delivery confirmation signal and the third radio signal retransmitted from the first radio apparatus according to the delivery confirmation signal are spatially multiplexed by the spatial multiplexing method. Transmitted to the second wireless device,
The acknowledgment signal received from the second wireless device includes spatial multiplexing information for transmission to the second wireless device by a spatial multiplexing method,
The delivery confirmation signal is received not only by the own wireless device but also by the first wireless device,
The transmission means is a control program for a radio apparatus that transmits the second radio signal to the second radio apparatus by a spatial multiplexing method in accordance with the spatial multiplexing information .

Images