JP5349447B2 - Wireless communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless communication system capable of appropriately controlling whether direct communication is performed or not between wireless terminals (STAs). <P>SOLUTION: An access point 20 includes an acquisition unit 23 that acquires from a wireless terminal 10 a report on throughput between a pair of wireless terminals 10, a determination unit 24 that determines which communication mode to adopt out of an infrastructure mode and a direct mode based on the report on the throughput, and an instruction unit 25 that gives instructions to the wireless terminal 10 to shift to the communication mode determined by the determination unit 24. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention relates to a wireless communication system including a pair of wireless terminals and an access point.

  In recent years, MIMO (Multiple Input Multiple Output) technology has attracted attention as a technology for increasing the transmission rate (for example, Non-Patent Document 1). Specifically, in the MIMO technique, it is possible to transmit different data from each of a plurality of antennas to a wireless terminal (user terminal). Therefore, it is possible to increase the transmission capacity and improve the transmission reliability.

IEEE 802.11n, “Part 11; Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specification”, October 29, 2009

  By the way, in general, in a network such as a LAN (Local Area Network), communication between wireless terminals (hereinafter referred to as STAs) is performed via an access point (hereinafter referred to as AP).

  However, depending on the arrangement of STAs, there are situations where it is preferable to communicate directly between STAs rather than communicating via APs. In particular, when MIMO is applied, the transmission speed is assumed to vary greatly depending on the arrangement of the STAs because it is strongly influenced by a shielding object.

  Accordingly, the present invention has been made to solve the above-described problem, and a wireless communication system that can appropriately control whether or not direct communication is performed between wireless terminals (STAs). I will provide a.

The wireless communication system (wireless communication system 100) according to the first feature includes a pair of wireless terminals (wireless terminal 10) and an access point (access point 20) that communicates with the pair of wireless terminals. The access point is an acquisition unit (acquisition unit 23) that acquires a report of throughput between the pair of wireless terminals from a reporting terminal that is at least one of the pair of wireless terminals; Based on the throughput report, any one of an infrastructure mode for performing communication between the pair of wireless terminals via the access point and a direct mode for performing direct communication between the pair of wireless terminals A determination unit (determination unit 24) that determines whether to apply a communication mode, and an instruction unit (instruction unit 25) that instructs the pair of wireless terminals to shift to the communication mode determined by the determination unit possess the door, determination unit (determination unit 24), in the infrastructure mode, when the throughput is less than the predetermined threshold value Th1, or decrease the amount of throughput is a predetermined threshold value Th2 super If the determines to migrate the communication mode to direct mode.
The wireless communication system (wireless communication system 100) according to the second feature includes a pair of wireless terminals (wireless terminal 10) and an access point (access point 20) that communicates with the pair of wireless terminals. The access point is an acquisition unit (acquisition unit 23) that acquires a report of throughput between the pair of wireless terminals from a reporting terminal that is at least one of the pair of wireless terminals; Based on the throughput report, any one of an infrastructure mode for performing communication between the pair of wireless terminals via the access point and a direct mode for performing direct communication between the pair of wireless terminals A determination unit (determination unit 24) that determines whether to apply a communication mode, and an instruction unit (instruction unit 25) that instructs the pair of wireless terminals to shift to the communication mode determined by the determination unit In the direct mode, the determination unit (determination unit 24) has a throughput lower than the predetermined threshold Th3, or the amount of decrease in the throughput exceeds the predetermined threshold Th4. In the case, it is determined to shift the communication mode to the infrastructure mode.

In the first or second feature, the access point includes a request unit (request unit 26) that requests the reporting terminal to report the throughput.

In the first or second feature, the determination unit determines to shift the communication mode to the direct mode when the throughput in the infrastructure mode is lower than the throughput in the direct mode.

In the first or second feature, the determination unit determines to shift the communication mode to the infrastructure mode when the throughput in the direct mode is lower than the throughput in the infrastructure mode.

In the first or second feature, the determination unit determines whether or not to shift the communication mode to the direct mode based on a type of a packet transmitted by communication between the pair of wireless terminals.

In the first or second feature, the determination unit determines whether or not to shift the communication mode to the direct mode based on an amount of traffic transmitted by communication between the pair of wireless terminals.

In the first or second feature, in the infrastructure mode, the determination unit determines whether a buffer amount of data to be transmitted from one wireless terminal to the other wireless terminal among the pair of wireless terminals is a predetermined threshold Th5. If it exceeds, it is determined to shift the communication mode to the direct mode.

In the first or second feature, in the direct mode, the determination unit determines whether a buffer amount of data to be transmitted from one wireless terminal to the other wireless terminal among the pair of wireless terminals is a predetermined threshold Th6. If it exceeds, it is determined to shift the communication mode to the infrastructure mode.

In the first or second feature, the determination unit applies any communication mode of the infrastructure mode and the direct mode based on at least one of the communication quality of the direct mode and the communication quality of the infrastructure mode. Judge whether to do.

In the first or second feature, the communication quality in the direct mode is a communication response speed or a retransmission rate in the direct mode. The communication quality in the infrastructure mode is a communication response speed or a retransmission rate in the infrastructure mode.

In the first or second feature, the instruction unit, in the direct mode, based on a buffer amount of data to be transmitted from one wireless terminal to the other wireless terminal of the pair of wireless terminals, Instructing the pair of wireless terminals to increase or decrease the number of transmission paths used between the pair of wireless terminals.

In the first or second feature, in the direct mode, the instruction unit increases or decreases the number of transmission paths used between the pair of wireless terminals based on the amount of change in the throughput to the pair of wireless terminals. Instruct.

  ADVANTAGE OF THE INVENTION According to this invention, the radio | wireless communications system which enables appropriately controlling whether direct communication is performed between radio | wireless terminals (STA) can be provided.

FIG. 1 is a diagram illustrating a configuration of a wireless communication system 100 according to the first embodiment. FIG. 2 is a block diagram showing a configuration of the access point 20 according to the first embodiment. FIG. 3 is a diagram showing a message format according to the first embodiment. FIG. 4 is a flowchart showing the operation of the access point 20 according to the first embodiment. FIG. 5 is a flowchart showing the operation of the access point 20 according to the first embodiment. FIG. 6 is a block diagram showing the access point 20 according to the first modification.

  Hereinafter, a wireless communication system according to an embodiment of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

  However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones. Therefore, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

[Outline of Embodiment]
The wireless communication system according to the embodiment includes a pair of wireless terminals and an access point that communicates with the pair of wireless terminals. The access point has an access unit that acquires a throughput report between a pair of wireless terminals from a reporting terminal that is at least one of the pair of wireless terminals, and an access point based on the throughput report. A determination unit for determining which communication mode to apply between an infrastructure mode for performing communication between a pair of wireless terminals via a point and a direct mode for performing direct communication between a pair of wireless terminals; And an instruction unit that instructs a pair of wireless terminals to shift to the communication mode determined by the determination unit.

  In the embodiment, the determination unit determines which communication mode to apply between the infrastructure mode and the direct mode based on the throughput report acquired from the reporting terminal. Therefore, an appropriate communication mode can be applied to communication between a pair of wireless terminals.

  The throughput may be a link rate, an error rate, or an actually measured rate.

  The link rate is a theoretical value of a data transmission rate in communication between wireless terminals. For example, when AMC (Adaptive Modulation Coding) is applied, the link rate is a theoretical value calculated by a modulation scheme or a coding scheme selected based on the propagation environment.

  The error rate is a data error rate in communication between wireless terminals. For example, the error rate may be a bit error rate or a symbol error rate.

  The actual measurement rate is an actual measurement value of a data transmission rate in communication between wireless terminals. For example, the actual measurement rate is calculated based on an Echo message that is reciprocated between wireless terminals. Specifically, the actual measurement rate is the time until a single Echo message is successfully reciprocated.

  In the embodiment, a case where a MIMO (Multiple Input Multiple Output) scheme is applied in a wireless communication system will be described. Therefore, it goes without saying that the throughput varies depending not only on the propagation environment but also on the number of transmission paths used for communication.

[First Embodiment]
(Configuration of wireless communication system)
Hereinafter, the configuration of the wireless communication system according to the first embodiment will be described with reference to the drawings. FIG. 1 is a diagram illustrating a configuration of a wireless communication system 100 according to the first embodiment.

  As illustrated in FIG. 1, the wireless communication system 100 includes a pair of wireless terminals 10 (a wireless terminal 10 </ b> A and a wireless terminal 10 </ b> B) and an access point 20.

  The wireless terminal 10 is configured to communicate user data with other wireless terminals 10, for example. Each wireless terminal 10 has a plurality of antennas 11. Here, the radio terminal 10A includes an antenna 11AA and an antenna 11AB. The wireless terminal 10B includes an antenna 11BA and an antenna 11BB.

  The access point 20 is configured to relay user data between a pair of wireless terminals 10. The access point 20 has a plurality of antennas 21 (here, antennas 21A to 21G).

  Here, in the first embodiment, a MIMO (Multiple Input Multiple Output) technique is used. Specifically, a transmission path can be set between each of the plurality of antennas 11 provided in the wireless terminal 10 and each of the plurality of antennas 21 provided in the access point 20. Alternatively, it is possible to set a transmission path between each of the plurality of antennas 11 provided in the wireless terminal 10A and each of the plurality of antennas 11 provided in the wireless terminal 10B.

  Hereinafter, a communication mode for performing communication between a pair of wireless terminals 10 via the access point 20 is referred to as an infrastructure mode. On the other hand, a communication mode in which direct communication is performed between a pair of wireless terminals 10 is referred to as a direct mode.

  It is assumed that the wireless terminal 10 and the access point 20 have a wireless communication function that complies with, for example, IEEE 802.11n.

(Access point configuration)
Hereinafter, the configuration of the access point according to the first embodiment will be described with reference to the drawings. FIG. 2 is a block diagram showing a configuration of the access point 20 according to the first embodiment.

  As illustrated in FIG. 2, the access point 20 includes a plurality of antennas 21, a communication unit 22, an acquisition unit 23, a determination unit 24, and an instruction unit 25.

  Each antenna 21 transmits a signal via an individual transmission path. Similarly, each antenna 21 receives a signal via an individual transmission path.

  The communication unit 22 transmits a signal via each antenna 21. Similarly, the communication unit 22 receives a signal via each antenna 21. Specifically, the communication unit 22 performs signal modulation, signal demodulation, signal encoding, signal decoding, and the like.

  In addition, the communication unit 22 has a function of performing communication in accordance with an LLTD (Link Layer Topology Discovery) protocol.

  The acquisition unit 23 acquires a throughput report between the pair of wireless terminals 10. The acquisition unit 23 acquires a throughput report from at least one of the pair of wireless terminals 10 (reporting terminal). The acquisition unit 23 may acquire throughput reports from both the pair of wireless terminals 10.

  The throughput may be a link rate, an error rate, or an actually measured rate.

  The link rate is a theoretical value of the transmission rate of data (for example, user data) in communication between the wireless terminals 10. For example, when AMC (Adaptive Modulation Coding) is applied, the link rate is a theoretical value calculated by a modulation scheme or a coding scheme selected based on the propagation environment.

  The error rate is an error rate of data (for example, user data) in communication between the wireless terminals 10. For example, the error rate may be a bit error rate or a symbol error rate. Of course, the higher the error rate, the lower the throughput.

  The actual measurement rate is an actual measurement value of the transmission speed of data (for example, user data) in communication between the wireless terminals 10. For example, the actual measurement rate is calculated based on an Echo message that is reciprocated between the wireless terminals 10. Specifically, the actual measurement rate is a time (average time or the like) until a single Echo message is successfully reciprocated. For details of the actual measurement rate, Japanese Patent Application No. 2009-129933 should be referred to, for example.

  The determination unit 24 determines a communication mode to be applied to communication between the pair of wireless terminals 10. The communication mode is an infrastructure mode in which communication between the pair of wireless terminals 10 is performed via the access point 20 and a direct mode in which direct communication is performed between the pair of wireless terminals 10. It should be noted that in the direct mode, the access point 20 does not relay data (for example, user data).

  Specifically, the determination unit 24 determines a communication mode to be applied to communication between the pair of wireless terminals 10 based on the throughput report. As a method for determining the communication mode, for example, the following method can be considered.

  (1) The determination unit 24 determines to shift the communication mode to the direct mode when the throughput is lower than the predetermined threshold Th1 in the infrastructure mode. That is, the determination unit 24 determines that the communication mode should be switched directly to the mode when the throughput of the infrastructure mode is low.

  (2) In the infrastructure mode, the determination unit 24 determines to shift the communication mode to the direct mode when the amount of decrease in throughput exceeds the predetermined threshold Th2. That is, in the infrastructure mode, the determination unit 24 determines that the communication mode should be switched directly to the mode when the initial throughput cannot be secured and the throughput decreases.

  (3) In the direct mode, the determination unit 24 determines to shift the communication mode to the infrastructure mode when the throughput is lower than the predetermined threshold Th3. That is, the determination unit 24 determines that the communication mode should be switched to the infrastructure mode when the direct mode throughput is low.

  (4) In the direct mode, the determination unit 24 determines to shift the communication mode to the infrastructure mode when the throughput reduction amount exceeds the predetermined threshold Th4. In the direct mode, the determination unit 24 determines that the communication mode should be switched to the infrastructure mode when the initial throughput cannot be ensured and the throughput decreases.

  (5) The determination unit 24 determines to shift the communication mode to the direct mode when the throughput in the infrastructure mode is lower than the throughput in the direct mode.

  (6) The determination unit 24 determines to shift the communication mode to the infrastructure mode when the throughput in the direct mode is lower than the throughput in the infrastructure mode.

  Thus, the determination unit 24 determines that the optimum communication mode should be applied from the infrastructure mode and the direct mode based on the throughput in each communication mode. Note that the determination unit 24 may be configured not to re-switch the communication mode over a certain period after switching the communication mode.

  Note that the determination unit 24 may determine to shift the communication mode to the direct mode when the throughput is lower than the predetermined threshold Th1 and the amount of decrease in the throughput exceeds the predetermined threshold Th2 in the infrastructure mode. Alternatively, the determination unit 24 may determine to shift the communication mode to the infrastructure mode when the throughput is lower than the predetermined threshold Th3 and the amount of decrease in the throughput exceeds the predetermined threshold Th4 in the direct mode.

  Or the determination part 24 may determine the communication mode which should be applied to communication of a pair of radio | wireless terminal 10 based on communication quality. Here, the communication quality is, for example, a communication response speed or a retransmission rate (number of retransmissions).

  First, the communication response speed will be described. For example, in the direct mode, the communication response speed is measured by the time from the transmission of the Echo message to the reception of the Echo message by reciprocating the Echo message directly between the wireless terminals 10. In the infrastructure mode, the communication response speed is measured by the time from the transmission of the Echo message to the reception of the Echo message by reciprocating the Echo message between the wireless terminals 10 via the access point 20.

  Note that the communication response speed may be measured at a layer 2 such as a MAC layer, or may be measured at a layer higher than the layer 2 (for example, an application layer).

  The determination unit 24 determines a communication mode to be applied to the communication of the pair of wireless terminals 10 based on at least one of the direct mode communication response speed and the infrastructure mode communication response speed. For example, the determination unit 24 determines to shift the communication mode from the direct mode (or the infrastructure mode) to the infrastructure mode (or the direct mode) when the packet response speed is lower than a predetermined threshold.

  Or the determination part 24 determines the communication mode which should be applied to communication of a pair of radio | wireless terminal 10 based on the comparison result of the communication response speed of direct mode, and the communication response speed of infrastructure mode. Specifically, the determination unit 24 determines to shift the communication mode to the direct mode when the communication response speed in the direct mode is smaller than the communication response speed in the infrastructure mode by a predetermined threshold or more. Conversely, the determination unit 24 determines to shift the communication mode to the infrastructure mode when the communication response speed in the infrastructure mode is smaller than the communication response speed in the direct mode by a predetermined threshold or more.

  Second, the retransmission rate will be described. The retransmission rate is measured by the number of retransmissions counted by the retransmission counter within a certain time (for example, 100 msec). Note that the number of retransmissions is preferably measured in a layer to which retransmission control is applied. For example, the retransmission rate may be measured in layer 2 such as the MAC layer, or may be measured in a layer higher than layer 2 (for example, an application layer).

  The determination unit 24 determines a communication mode to be applied to the communication of the pair of wireless terminals 10 based on at least one of the retransmission rate in the direct mode and the retransmission rate in the infrastructure mode. For example, the determination unit 24 determines to shift the communication mode from the direct mode (or the infrastructure mode) to the infrastructure mode (or the direct mode) when the retransmission rate is lower than a predetermined threshold.

  Alternatively, the determination unit 24 determines the communication mode to be applied to the communication of the pair of wireless terminals 10 based on the comparison result between the retransmission rate in the direct mode and the retransmission rate in the infrastructure mode. Specifically, the determination unit 24 determines to shift the communication mode to the direct mode when the retransmission rate in the direct mode is smaller than the retransmission rate in the infrastructure mode by a predetermined threshold or more. Conversely, the determination unit 24 determines to shift the communication mode to the infrastructure mode when the retransmission rate in the infrastructure mode is smaller than the retransmission rate in the direct mode by a predetermined threshold or more.

  Note that the determination unit 24 may determine the communication mode to be applied to the communication of the pair of wireless terminals 10 based on both the throughput and the communication quality.

  The instruction unit 25 instructs the pair of wireless terminals 10 to shift to the communication mode determined by the determination unit 24. For example, the instruction unit 25 instructs the pair of wireless terminals 10 to shift to the direct mode when the determination unit 24 determines to shift the communication mode to the direct mode. Similarly, the instruction unit 25 instructs the pair of wireless terminals 10 to shift to the infrastructure mode when the determination unit 24 determines to shift the communication mode to the infrastructure mode.

(Message format)
Hereinafter, an example of the message format according to the first embodiment will be described with reference to the drawings. FIG. 3 is a diagram illustrating an example of a message format according to the first embodiment. Here, in FIG. 3, an MPDU is illustrated as a data unit, and an A-MPDU is illustrated as an aggregate data unit configured by a plurality of data units.

  As shown in FIG. 3, the A-MPDU is composed of a plurality of MPDUs. The A-MPDU includes a CRC, an MPDU header, an MPDU payload, FCS, and PAD. The CRC, MPDU header, MPDU payload, FCS, and PAD constitute one frame.

  CRC (Cyclic Redundancy Check) is a bit string used for error detection of one frame.

  The MPDU header is an MPDU header. The MPDU header includes frame control, duration, address, sequence control, QoS control, and the like. Frame control is a field indicating the configuration of a subframe included in the MPDU payload. The duration is a field indicating an estimated time required for carrying the MPDU. The address is a field indicating the destination of the MPDU. The sequence control is a field indicating the order of MPDU. The QoS control is a field indicating the quality required for the MPDU.

  The MPDU payload includes user data or error correction data. For example, when the A-MPDU includes a user data unit, the MPDU payload includes user data. When the A-MPDU includes an error correction data unit, the MPDU payload includes error correction data.

  FCS (Frame Check Sequence) is a bit string used for error detection and error detection of one frame.

  PAD (Padding Data) is a bit string for adjusting the data length included in one frame. For example, the PAD is a bit string for adjusting the lack of data so that one frame length is an integer byte.

(Access point operation)
Hereinafter, the operation of the access point according to the first embodiment will be described with reference to the drawings. 4 and 5 are flowcharts showing the operation of the access point 20 according to the first embodiment. FIG. 4 shows a flow for determining whether or not to shift the communication mode to the direct mode in the infrastructure mode. FIG. 5 shows a flow for determining whether or not to shift the communication mode to the infrastructure mode in the direct mode.

  First, a flow for determining whether or not to shift the communication mode to the direct mode in the infrastructure mode will be described with reference to FIG.

  As shown in FIG. 4, in step 110, the infrastructure mode is applied to communication between the pair of wireless terminals 10.

  In step 120, the access point 20 acquires a throughput report from at least one radio terminal 10 (reporting terminal) of the pair of radio terminals 10.

  In step 130, the access point 20 determines a communication mode to be applied to communication between the pair of wireless terminals 10. For example, the access point 20 determines to shift the communication mode to the direct mode when the throughput is lower than the predetermined threshold Th1 in the infrastructure mode. Alternatively, the access point 20 determines to shift the communication mode to the direct mode when the throughput reduction amount exceeds the predetermined threshold Th2 in the infrastructure mode. Alternatively, the access point 20 determines to shift the communication mode to the direct mode when the throughput is lower than the predetermined threshold Th1 and the amount of decrease in the throughput exceeds the predetermined threshold Th2 in the infrastructure mode.

  Note that the access point 20 may determine to shift the communication mode to the direct mode when the throughput in the infrastructure mode is lower than the throughput in the direct mode.

  In step 140, the access point 20 determines whether or not it is determined to shift the communication mode to the direct mode. If the access point 20 determines to shift the communication mode to the direct mode, the access point 20 proceeds to the process of step 150. On the other hand, if it is determined that the communication mode is not shifted to the direct mode, the access point 20 proceeds to the process of step 160.

  In step 150, the access point 20 instructs the pair of wireless terminals 10 to shift to the direct mode.

  In step 160, the access point 20 maintains the infrastructure mode without shifting the communication mode.

  Second, the flow for determining whether or not to shift the communication mode to the infrastructure mode in the direct mode will be described with reference to FIG.

  As shown in FIG. 5, in step 210, the direct mode is applied to communication between a pair of wireless terminals 10.

  In step 220, the access point 20 acquires a throughput report from at least one wireless terminal 10 (reporting terminal) of the pair of wireless terminals 10.

  In step 230, the access point 20 determines a communication mode to be applied to communication between the pair of wireless terminals 10. For example, the access point 20 determines to shift the communication mode to the infrastructure mode when the throughput is lower than the predetermined threshold Th3 in the direct mode. Alternatively, the access point 20 determines to shift the communication mode to the infrastructure mode when the throughput reduction amount exceeds the predetermined threshold Th4 in the direct mode. Alternatively, the access point 20 determines to shift the communication mode to the infrastructure mode when the throughput is lower than the predetermined threshold Th3 and the amount of decrease in the throughput exceeds the predetermined threshold Th4 in the direct mode.

  Note that the access point 20 may determine to shift the communication mode to the infrastructure mode when the throughput in the direct mode is lower than the throughput in the infrastructure mode.

  In step 240, the access point 20 determines whether or not it is determined to shift the communication mode to the infrastructure mode. When it is determined that the access point 20 shifts the communication mode to the infrastructure mode, the access point 20 proceeds to the process of step 250. On the other hand, when it is determined that the communication mode is not shifted to the infrastructure mode, the access point 20 proceeds to the process of step 260.

  In step 250, the access point 20 instructs the pair of wireless terminals 10 to shift to the infrastructure mode.

  In step 260, the access point 20 maintains the direct mode without changing the communication mode.

(Function and effect)
In the first embodiment, the determination unit 24 determines which communication mode to apply between the infrastructure mode and the direct mode based on the throughput report acquired from the reporting terminal. Therefore, an appropriate communication mode can be applied to communication between a pair of wireless terminals.

  For example, when the throughput is low, by switching the communication mode, the optimal communication mode at that time can be applied. In addition, when the initial throughput cannot be ensured and the throughput decreases, the communication mode that is optimal at that time can be applied by switching the communication mode.

  In particular, when MIMO is applied, the transmission speed is assumed to vary greatly depending on the arrangement of the STAs because it is strongly influenced by a shielding object. Therefore, it should be noted that when MIMO is applied, it is important to determine whether to apply the communication mode based on the throughput report.

[Modification 1]
Hereinafter, Modification Example 1 of the first embodiment will be described. In the following, differences from the first embodiment will be mainly described.

  Specifically, in the first modification, as illustrated in FIG. 6, the access point 20 includes a request unit 26 in addition to the configuration illustrated in FIG. 2. The request unit 26 requests the reporting terminal to report the throughput. For example, the requesting unit 26 requests a throughput report at regular intervals. Alternatively, the request unit 26 requests a throughput report when the communication mode is switched.

[Modification 2]
Hereinafter, Modification Example 2 of the first embodiment will be described. In the following, differences from the first embodiment will be mainly described.

  Specifically, in the second modification, the determination unit 24 determines whether or not to shift the communication mode to the direct mode based on the type of packet transmitted by communication between the pair of wireless terminals 10.

  For example, the determination unit 24 determines to shift the communication mode to the direct mode when a packet transmitted by communication between the pair of wireless terminals 10 is a packet that requires real-time property. Alternatively, the determination unit 24 determines to shift the communication mode to the direct mode when a packet transmitted by communication between the pair of wireless terminals 10 has a QoS parameter with a large traffic volume.

[Modification 3]
Hereinafter, Modification 3 of the first embodiment will be described. In the following, differences from the first embodiment will be mainly described.

  Specifically, in the third modification, the determination unit 24 determines whether or not to shift the communication mode to the direct mode based on the amount of traffic transmitted by communication between the pair of wireless terminals 10.

  For example, the determination unit 24 determines whether or not to shift the communication mode to the direct mode when the amount of traffic transmitted by communication between the pair of wireless terminals 10 is larger than a predetermined threshold.

[Modification 4]
Hereinafter, Modification 4 of the first embodiment will be described. In the following, differences from the first embodiment will be mainly described.

  Specifically, in the fourth modification, the determination unit 24 determines that the buffer amount of data to be transmitted from one wireless terminal 10 to the other wireless terminal 10 out of the pair of wireless terminals 10 in the infrastructure mode is a predetermined threshold value. When Th5 is exceeded, it is determined that the communication mode is shifted to the direct mode. That is, in the infrastructure mode, when data stays in the buffer provided in the wireless terminal 10, the determination unit 24 determines to switch the communication mode to the direct mode.

  Alternatively, in the fourth modification, the determination unit 24 determines that the buffer amount of data to be transmitted from one wireless terminal 10 to the other wireless terminal 10 out of the pair of wireless terminals 10 exceeds the predetermined threshold Th6 in the direct mode. If it is determined that the communication mode is switched to the infrastructure mode. That is, in the direct mode, when data stays in the buffer provided in the wireless terminal 10, the determination unit 24 determines to switch the communication mode to the infrastructure mode.

[Modification 5]
Hereinafter, Modification 5 of the first embodiment will be described. In the following, differences from the first embodiment will be mainly described.

  Specifically, in the fifth modification, the instruction unit 25 is based on the buffer amount of data to be transmitted from one wireless terminal 10 to the other wireless terminal 10 out of the pair of wireless terminals 10 in the direct mode. Instructs the pair of wireless terminals 10 to increase or decrease the number of transmission paths used between the pair of wireless terminals 10. Specifically, in the direct mode, when there is a large amount of data in a buffer provided in the wireless terminal 10, the instruction unit 25 increases the number of transmission paths used between the pair of wireless terminals 10. The terminal 10 is instructed. On the other hand, in the direct mode, when there is a small amount of data in the buffer provided in the wireless terminal 10 or when there is no data retention, the instruction unit 25 is connected between the pair of wireless terminals 10. It instructs the pair of wireless terminals 10 to reduce the number of transmission paths to be used.

[Modification 6]
Hereinafter, Modification Example 6 of the first embodiment will be described. In the following, differences from the first embodiment will be mainly described.

  Specifically, in Modification 6, the instruction unit 25 increases or decreases the number of transmission paths used between a pair of wireless terminals 10 based on the amount of change in throughput in the direct mode. Instruct. Specifically, in the direct mode, when the current throughput is lower than the throughput required for communication between the pair of wireless terminals 10, the instruction unit 25 determines the number of transmission paths used between the pair of wireless terminals 10. An increase is instructed to the pair of wireless terminals 10. On the other hand, in the direct mode, when the current throughput is higher than the throughput required for communication between the pair of wireless terminals 10, the instruction unit 25 reduces the number of transmission paths used between the pair of wireless terminals 10. To the pair of wireless terminals 10.

[Modification 7]
Hereinafter, Modification Example 7 of the first embodiment will be described. In the following, differences from the first embodiment will be mainly described.

  Specifically, in the modification example 7, the instruction unit 25 is based on the buffer amount of data to be transmitted from one wireless terminal 10 to the other wireless terminal 10 out of the pair of wireless terminals 10 in the infrastructure mode. Instructs the pair of wireless terminals 10 to increase or decrease the number of transmission paths used between the pair of wireless terminals 10. Specifically, in the infrastructure mode, when there is a large amount of data stored in the buffer provided in the wireless terminal 10, the instruction unit 25 increases the number of transmission paths used between the pair of wireless terminals 10. The terminal 10 is instructed. On the other hand, in the infrastructure mode, when the amount of data staying in the buffer provided in the wireless terminal 10 is small, or when there is no data staying, the instruction unit 25 is set between the pair of wireless terminals 10. It instructs the pair of wireless terminals 10 to reduce the number of transmission paths to be used.

[Modification 8]
Hereinafter, Modification Example 8 of the first embodiment will be described. In the following, differences from the first embodiment will be mainly described.

  Specifically, in the modification example 8, the instruction unit 25 increases or decreases the number of transmission paths used between a pair of wireless terminals 10 to the pair of wireless terminals 10 based on the amount of change in throughput in the infrastructure mode. Instruct. Specifically, when the current throughput is lower than the throughput required for communication between the pair of wireless terminals 10 in the infrastructure mode, the instruction unit 25 determines the number of transmission paths used between the pair of wireless terminals 10. An increase is instructed to the pair of wireless terminals 10. On the other hand, in the infrastructure mode, when the current throughput is higher than the throughput required for communication between the pair of wireless terminals 10, the instruction unit 25 reduces the number of transmission paths used between the pair of wireless terminals 10. To the pair of wireless terminals 10.

[Other Embodiments]
Although the present invention has been described with reference to the above-described embodiments, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  Although not particularly mentioned in the embodiment, the wireless terminal 10 may autonomously transmit a throughput report to the access point 20. For example, the wireless terminal 10 transmits a throughput report at regular intervals. Alternatively, the wireless terminal 10 transmits a throughput report when the communication mode is switched.

  Modification examples 1 to 8 may be applied to the first embodiment in combination with other modification examples different from each other. That is, two or more modification examples selected from Modification Examples 1 to 8 may be applied to the first embodiment.

  The above-described threshold values Th1 to Th6 can be arbitrarily determined. That is, the threshold values Th1 to Th6 may be different values or the same value.

  DESCRIPTION OF SYMBOLS 10 ... Wireless terminal, 11 ... Antenna, 20 ... Access point, 21 ... Antenna, 22 ... Communication part, 23 ... Acquisition part, 24 ... Determination part, 25 ... Instruction part, 26 ... Request part, 100 ... Wireless communication system

Claims (3)

A wireless communication system comprising a pair of wireless terminals and an access point for communicating with the pair of wireless terminals,
The access point is
An acquisition unit that acquires a report of throughput between the pair of wireless terminals from a reporting terminal that is at least one of the pair of wireless terminals;
Based on the throughput report, any one of an infrastructure mode for performing communication between the pair of wireless terminals via the access point and a direct mode for performing direct communication between the pair of wireless terminals A determination unit for determining whether to apply a communication mode;
An instruction unit that instructs the pair of wireless terminals to shift to the communication mode determined by the determination unit;
In the infrastructure mode, the determination unit determines to shift the communication mode to the direct mode when the throughput is lower than the predetermined threshold Th1, or when the amount of decrease in the throughput exceeds the predetermined threshold Th2. A wireless communication system. A wireless communication system comprising a pair of wireless terminals and an access point for communicating with the pair of wireless terminals,
The access point is
An acquisition unit that acquires a report of throughput between the pair of wireless terminals from a reporting terminal that is at least one of the pair of wireless terminals;
Based on the throughput report, any one of an infrastructure mode for performing communication between the pair of wireless terminals via the access point and a direct mode for performing direct communication between the pair of wireless terminals A determination unit for determining whether to apply a communication mode;
An instruction unit that instructs the pair of wireless terminals to shift to the communication mode determined by the determination unit;
In the direct mode, the determination unit determines to shift the communication mode to the infrastructure mode when the throughput is lower than the predetermined threshold Th3 or when the amount of decrease in the throughput exceeds the predetermined threshold Th4. A wireless communication system.   The wireless communication system according to claim 1, wherein the access point includes a request unit that requests the reporting terminal to report the throughput.

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