Terminal, communication method, and recording medium

Abstract

The invention provides a terminal, a communication method, and a recording medium. A terminal is provided with: a measurement unit that measures at least one of a delay when a wireless signal is transmitted to an access point and a fluctuation in the wireless signal; a data processing unit that generates information including a result of the measurement; and a wireless signal processing unit that transmits the information to the access point, and the measurement unit measures the delay on the basis of the time from the start of the transmission of the wireless signal by the wireless signal processing unit until the reception of the confirmation from the access point.

Description

[0001] This application is a divisional application of the following patent application: the application date is January 10, 2020, the application number is 202080092567.X, and the invention title is "Terminal, Communication Method, and Recording Medium". Technical Field

[0002] The embodiment relates to a terminal, a communication method, and a recording medium. Background Art

[0003] An access point and a terminal of a wireless LAN use CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance) to access a channel and transmit a wireless signal. In CSMA / CA, the access point and the terminal wait for a time specified by an access parameter, and after confirming through carrier sensing that no other terminal or the like is using the channel, transmit a wireless signal.

[0004] As one of the priority control methods in a wireless LAN, EDCA (Enhanced Distribution Channel Access) is defined. In EDCA, traffic from a higher layer is classified into any one of four access categories (ACs), namely AC_VO (Voice), AC_VI (Video), AC_BE (Best effort), and AC_BK (Background). Moreover, in EDCA, CSMA / CA is performed for each access category. In EDCA, access parameters are allocated so that the transmission of wireless signals is relatively prioritized in the order of AC_VO, AC_VI, AC_BE, and AC_BK.

[0005] Prior Art Documents

[0006] Non-Patent Documents

[0007] Non-Patent Document 1: IEEE Std 802.11-2016, "10.22.2 HCF contention based channel access (EDCA)", 7 December 2016 Summary of the Invention

[0008] Problems to be Solved by the Invention

[0009] Relative prioritization between traffic flows is performed by EDCA. Here, for example, RTAs (Real-Time Applications) such as online games and the control of industrial robots have absolute latency and fluctuating request conditions for each application. In the case of only relative prioritization, it is not clear whether RTAs can be utilized, or whether control can be performed to enable RTAs to be utilized.

[0010] Means for Solving the Problem

[0011] A terminal of one embodiment includes a measurement unit, a data processing unit, and a wireless signal processing unit. The measurement unit measures at least one of the latency and the fluctuation of a wireless signal when transmitting the wireless signal to an access point. The data processing unit generates information including the measurement result. The wireless signal processing unit transmits the information to the access point.

[0012] According to the embodiment, even in the presence of absolute latency and fluctuating request conditions, information for determining whether it is suitable for the request conditions can be provided. Description of the Drawings

[0013] Figure 1 It is a diagram showing the structure of an example of the communication system according to the embodiment.

[0014] Figure 2 It is a diagram showing an example of the hardware configuration of an access point.

[0015] Figure 3 It is a diagram showing an example of the hardware configuration of a terminal.

[0016] Figure 4 It is a diagram showing the processing of the MAC (Media Access Control) layer when the access point communicates with the terminal.

[0017] Figure 5 It is a functional block diagram of an access point.

[0018] Figure 6 It is a functional block diagram of a terminal.

[0019] Figure 7A It is a diagram showing the first example of the format of the reported MAC payload.

[0020] Figure 7B It is a diagram showing the second example of the format of the reported MAC payload.

[0021] Figure 8A It is a diagram showing the first example of the access point requesting a report using an Action frame.

[0022] Figure 8B It is a diagram showing the second example of the access point requesting a report using an Action frame.

[0023] Figure 9A This is a diagram showing the first example of a management frame or control frame used by an access point to request a report.

[0024] Figure 9B This is a diagram showing the second example of a management frame or control frame used by an access point to request a report.

[0025] Figure 10 This is a flowchart showing the transmission process of an example of a terminal.

[0026] Figure 11 This is a flowchart showing the reporting process in a terminal.

[0027] Figure 12 This is a flowchart showing the reception process of an example of an access point.

[0028] Figure 13 This is a flowchart showing the reporting process in an access point.

[0029] Figure 14 This is a diagram showing a modified example. Detailed implementation manners

[0030] Hereinafter, the implementation manners will be described based on the accompanying drawings. Figure 1 This is a diagram showing the structure of an example of a communication system according to the implementation manner. The communication system 1 includes an access point 10 and a terminal 20. The access point 10 performs wireless LAN communication with terminals within a predetermined service area. Although not shown in Figure 1 , communication between terminals 20 can also be performed.

[0031] Figure 2 This is a diagram showing the hardware configuration of an example of the access point 10. The access point 10 is an access point (AP) for the terminal 20. The access point 10 is not limited to being fixed and can also be mounted on a moving body.

[0032] The access point 10 includes a processor 11, a ROM (Read Only Memory), a RAM (Random Access Memory) 13, a wireless module 14, and a router module 15.

[0033] The processor 11 is a processing device that controls the overall control of the access point 10. The processor 11 is, for example, a CPU (Central Processing Unit). The processor 11 is not limited to a CPU. In addition, an ASIC (Application Specific IC) or the like can be used instead of the CPU. In addition, the processor 11 can be more than one.

[0034] ROM 12 is a storage device dedicated for reading. ROM 12 stores the firmware and various programs required for the operation of the access point 10.

[0035] RAM 13 is a storage device that can be written to arbitrarily. RAM 13 is used as a working area for the processor 11 and temporarily stores the firmware etc. stored in ROM 12.

[0036] The wireless module 14 is a module configured to perform the processing required for wireless LAN communication. The wireless module 14 forms a MAC frame based on, for example, the data forwarded from the processor 11, converts the formed MAC frame into a wireless signal and transmits it to the terminal 20. In addition, the wireless module 14 receives a wireless signal from the terminal 20, reads out the data from the received wireless signal, and forwards it to, for example, the processor 11.

[0037] The router module 15 is provided so that the access point 10 communicates with, for example, a server (not shown) via a network. In addition, the access point 10 does not necessarily have to have the router module 15. The access point 10 can be configured to access a router provided outside the access point 10 through wireless communication or wired communication and connect to the network via the router.

[0038] Figure 3 It is a diagram showing an example of the hardware configuration of the terminal 20. The terminal 20 is a terminal device (station) such as a smart phone. The terminal 20 can be either a mobile terminal, a terminal mounted on a moving body, or a fixed terminal.

[0039] The terminal 20 includes a processor 21, a ROM 22, a RAM 23, a wireless module 24, a display 25, and a storage 26.

[0040] The processor 21 is a processing device that controls the overall operation of the terminal 20. The processor 21 is, for example, a CPU. The processor 21 is not limited to a CPU. In addition, an ASIC etc. can be used instead of the CPU. In addition, the processor 21 can be two or more instead of one.

[0041] ROM 22 is a storage device dedicated for reading. ROM 22 stores the firmware and various programs required for the operation of the terminal 20.

[0042] RAM 23 is a storage device that can be written to arbitrarily. RAM 23 is used as a working area for the processor 21 and temporarily stores the firmware etc. stored in ROM 22.

[0043] The wireless module 24 is a module configured to perform processing required for wireless LAN communication. The wireless module 24 forms a MAC frame for wireless communication based on data forwarded from the processor 21, for example, converts the formed MAC frame into a wireless signal, and transmits it to the access point 10. In addition, the wireless module 24 receives a wireless signal from the access point 10, reads data from the received wireless signal, and forwards it to the processor 21, for example.

[0044] The display 25 is a display device that displays various screens. The display 25 may be a liquid crystal display, an organic EL display, or the like. In addition, the display 25 may be provided with a touch panel.

[0045] The storage 26 is a storage device such as a hard disk. The storage 26 stores various applications executed by the processor 21, for example.

[0046] Figure 4 This is a diagram showing the processing of the MAC (Media Access Control) layer when the access point 10 communicates with the terminal 20. In Figure 4 both the processing on the transmission side and the processing on the reception side are shown. When the wireless module on one of the access point 10 and the terminal 20 performs the processing on the transmission side, the wireless module on the other side performs the processing on the reception side. In the following examples, the wireless modules on the transmission side and the reception side are described without distinction.

[0047] First, the processing on the transmission side will be described. In step S10, the wireless module performs A-MSDU aggregation. Specifically, the wireless module combines a plurality of data input from a higher layer such as the application layer to generate an A-MSDU (Aggregate-MAC service data unit).

[0048] In step S11, the wireless module assigns a sequence number (SN) to the A-MSDU. The sequence number is a unique number used to identify the A-MSDU.

[0049] In step S12, the wireless module segments (fragments) the A-MSDU into a plurality of MPDUs (MAC protocol data units).

[0050] In step S13, the wireless module encrypts each MPDU to generate an encrypted MPDU.

[0051] In step S14, the wireless module attaches a MAC header and an error detection code (FCS) to each encrypted MPDU. The error detection code is, for example, a CRC (Cyclic Redundancy Check) code.

[0052] In step S15, the wireless module performs A-MPDU aggregation. Specifically, the wireless module combines multiple MPDUs to generate an A-MPDU (Aggregate-MAC protocol data unit) that serves as a MAC frame.

[0053] After step S15, the wireless module performs physical layer processing on the MAC frame. That is, the wireless module performs modulation processing and the like on the MAC frame to generate a wireless signal, and sends the wireless signal to the access point 10.

[0054] Next, the processing on the receiving side will be described. If a wireless signal is received, the wireless module performs physical layer processing to recover the MAC frame from the wireless signal. After that, the wireless module performs Figure 4 the MAC layer processing as shown.

[0055] In step S20, the wireless module performs A-MPDU de-aggregation. Specifically, the wireless module divides the A-MPDU into units of MPDUs.

[0056] In step S21, the wireless module performs error detection. For example, the wireless module determines whether the reception of the wireless signal is successful through CRC. When the reception of the wireless signal fails, the wireless module can make a retransmission request. At this time, the wireless module can also request retransmission in units of MPDUs. On the other hand, when the reception of the wireless signal is successful, the wireless module performs the following processing.

[0057] In step S22, the wireless module performs address detection. At this time, the wireless module determines whether the sent MPDU is destined for itself through the address recorded in the MAC header of each MPDU. When it is not destined for itself, the wireless module does not perform the following processing. When it is destined for itself, the wireless module performs the following processing.

[0058] In step S23, the wireless module decrypts the encrypted MPDU.

[0059] In step S24, the wireless module performs defragmentation on the MPDUs. In other words, the wireless module recovers an A-MSDU from multiple MPDUs.

[0060] In step S25, the wireless module performs A-MSDU de-aggregation. Specifically, the wireless module restores the A-MSDU to data in units of MSDUs.

[0061] After step S25, the wireless module outputs the data to the upper layer of the MAC layer. The upper layer is, for example, the application layer.

[0062] Figure 5This is a functional block diagram of access point 10. The access point 10 includes: a data processing unit 101, a wireless signal processing unit 102, and a management unit 103. The data processing unit 101, the wireless signal processing unit 102, and the management unit 103 are implemented, for example, by a processor 11 and a wireless module 14.

[0063] The data processing unit 101 forms a MAC frame based on data forwarded from a server on the network, for example. In addition, the data processing unit 101 restores data based on the MAC frame forwarded from the wireless signal processing unit 102. This data includes reports sent from the terminal 20.

[0064] The wireless signal processing unit 102 performs processing for transmitting or receiving wireless signals. For example, the wireless signal processing unit 102 converts the MAC frame formed by the data processing unit 101 into a wireless signal and transmits the wireless signal to the terminal 20. In addition, the wireless signal processing unit 102 receives a wireless signal from the terminal 20, extracts the MAC frame from the received wireless signal, and forwards it to the data processing unit 101.

[0065] The management unit 103 manages the reports sent from the terminal 20. For example, the management unit 103 stores the reports in advance and uses the information stored in the reports at the required timing. This report includes information related to the delay or fluctuation of the transmission of wireless signals in the terminal 20. The details of the report will be described later.

[0066] Here, the wireless signal processing unit 102 can be configured to transmit wireless signals through EDCA, for example. In this case, the wireless signal processing unit 102 has transmission queues AC_VO, AC_VI, AC_BE, and AC_BK for each access category (AC). The transmission queue AC_VO is a queue for storing MAC frames classified as VO (Voice). The transmission queue AC_VI is a queue for storing MAC frames classified as VI (Video). The transmission queue AC_BE is a queue for storing MAC frames classified as BE (Best effort). The transmission queue AC_BK is a queue for storing MAC frames classified as BK (Background).

[0067] The wireless signal processing unit 102 maps the MAC frame forwarded from the data processing unit 101 to any one of the four access categories according to the type of data recorded in the MAC frame. According to the result of this mapping, the wireless signal processing unit 102 inputs the MAC frame into the corresponding transmission queue.

[0068] The wireless signal processing unit 102 confirms through carrier sensing for each access type that there is no wireless signal being transmitted by other terminals or the like, and makes the transmission wait for a time specified by the access parameters set for each access type. During the waiting period for transmission, if no other terminals or the like transmit wireless signals, the wireless signal processing unit 102 retrieves the MAC frame from the corresponding transmission queue, converts the MAC frame into a wireless signal, and transmits it.

[0069] Here, access parameters can also be allocated so that the transmission of wireless signals is relatively prioritized in the order of VO, VI, BE, BK. The access parameters can include CWmin, CWmax, AIFS, and TXOPLimit. CWmin and CWmax are respectively the maximum and minimum values of the transmission waiting time, that is, CW (Contention Window). The shorter CWmin and CWmax are, the easier it is for the transmission queue to obtain the transmission right. AIFS (Arbitration Inter Frame Space) is the transmission interval of wireless signals. The smaller AIFS is, the higher the priority of the transmission queue. TXOPLimit is the upper limit value of the channel occupancy time, that is, TXOP (Transmission Opportunity). The larger the value of TXOPLimit, the more wireless signals can be transmitted with one transmission right.

[0070] Figure 6 It is a functional block diagram of the terminal 20. The terminal 20 has a data processing unit 201, a wireless signal processing unit 202, and a measurement unit 203. The data processing unit 201, the wireless signal processing unit 202, and the measurement unit 203 are implemented, for example, by a processor 21 and a wireless module 24.

[0071] The data processing unit 201 constructs a MAC frame based on the data input from, for example, the upper-layer application. In addition, the data processing unit 201 restores the data based on the MAC frame forwarded from the wireless signal processing unit 202. This data is used by, for example, the upper-layer application. And the data processing unit 201 generates a report containing the measurement results of the measurement unit 203. Moreover, the data processing unit 201 constructs a MAC frame based on the report. Here, the application is not limited to a specific application. For example, the application can also be an RTA such as an online game or a control application for industrial robots.

[0072] The wireless signal processing unit 202 performs processing for transmitting or receiving wireless signals. For example, the wireless signal processing unit 202 converts the MAC frame formed by the data processing unit 201 into a wireless signal and transmits the wireless signal to the access point 10, for example. In addition, the wireless signal processing unit 202 receives a wireless signal from the access point 10, extracts the MAC frame from the received wireless signal, and forwards it to the data processing unit 201. Here, the wireless signal processing unit 202 may be configured to transmit a wireless signal by EDCA, for example, in the same manner as the access point 10.

[0073] The measurement unit 203 measures at least one of the delay in the transmission of the wireless signal and the fluctuation of the wireless signal in the terminal 20. For example, the delay is measured based on the time from the start of the transmission of the wireless signal by the wireless signal processing unit 202 until the receipt of an acknowledgment (ACK) from the access point 10. In addition, the delay can be measured based on the queue standby time from when the MAC frame is input to the end of the transmission queue until it reaches the front of the transmission queue. In addition, the delay can also be measured based on the transmission standby time from when the MAC frame reaches the front of the transmission queue until the transmission is performed. In addition, the delay can also be measured based on the required retransmission time from the request for retransmission until the retransmission is performed. Multiple of these delays can also be measured. For example, the fluctuation is measured based on the variance with respect to the average value of the delays. The method for measuring the delay and the method for measuring the fluctuation are not limited to specific methods. In addition, the time information used for the measurement may be provided to each functional unit by a common clock (not shown) provided in the terminal.

[0074] Figure 7A It is a diagram showing a first example of the format of the reported MAC payload. The reported payload includes a data field of the measurement results for each access type. The measurement results are at least one of the measurement results of the delay and the measurement results of the fluctuation. The measurement results may be the measured values of the delay or the fluctuation measured in each measurement, or may be statistical values calculated by performing statistical processing on the measured values measured in multiple measurements. Statistical values include values such as the average value, the median value, the maximum value, and the minimum value, for example. The reported payload may store any one of these statistical values for each access type, or may store multiple of them for each access type. Here, when calculating these statistical values such as the average value, the median value, the maximum value, and the minimum value, it is preferable to exclude outliers that deviate significantly from the results of other measurements from the results of multiple measurements. In addition, when measuring both the delay and the fluctuation, when the fluctuation is large, outliers are likely to occur. For example, the number of measured values used in the calculation of the average value can be reduced.

[0075] For example, Figure 7AThe shown report can be sent using the Action frame in the IEEE802.11 standard. For example, when the access point requests reports from each terminal, the request for the report can also be made through an Action frame with a new field added that contains a status notification request for requesting the report. The terminal replies with a report by receiving the Action frame. When replying with a report, the terminal can use an Action frame with a new field added that stores measurement results such as the storage delay. In this case, as Figure 8A shown, after receiving a request from the access point, the terminal can perform the normal CSMA / CA procedure to reply with a report. Additionally, as Figure 8B shown, after receiving a request from the access point, the terminal can also reply with a report quickly without performing the CSMA / CA procedure, for example, after passing through SIFS (Short Inter Frame Space) or PIFS (PCF Inter Frame Space). Additionally, the access point can also periodically report management frames or control frames for requesting reports, and each terminal sends a report. For example, the access point can also include a request for the report in a frame such as a beacon that is periodically sent. As Figure 9A shown, the terminal can also reply with a report to the request for the report through an Action frame. Additionally, as Figure 9B shown, the terminal can also append the report to a data frame. For example, when the terminal sends data with a limited delay, by applying information such as the delay measured when sending data of the same type (access type, etc.) as the previous time, the delay status can be notified to the access point in a relatively real-time manner. When appending a report to a data frame, for example, a new field for storing information such as the storage delay can be added to the header of the data frame.

[0076] Additionally, in Figure 7A , the measurement results are stored according to each access type. However, it is not necessarily required to store the report payload according to each access type. For example, there is also a wireless LAN transmission control method without priority control for each access type. In this case, there is no need to store the measurement results according to each access type. Additionally, instead of the access type, the measurement results can also be stored according to each traffic type (TID). A TID is assigned for each application (session) processed by the terminal 20. The mapping to the aforementioned access type can be based on the TID. By storing the measurement results according to each TID, the delay and fluctuation can be measured according to each application differentiation.

[0077] Figure 7BThis is a diagram showing a second example of the format of the MAC payload of a report. The payload of the report includes, in addition to the data fields of the measurement results for each access type, attribute information about the measurement results. The attribute information includes, for example, information related to the terminal such as the location of the terminal 20 at the time of measurement of delay or fluctuation, the type of the terminal 20, and the type of application being executed on the terminal 20.

[0078] Next, the operation of the communication system 1 will be described. In the following description, the terminal 20 transmits a wireless signal and the access point 10 receives the wireless signal.

[0079] Figure 10 This is a flowchart showing the transmission process of an example of the terminal 20. In step S31, the data processing unit 201 determines whether data to be transmitted from a higher layer such as the application layer is input. In step S31, when it is determined that no data is input, Figure 10 the process ends. In step S31, when it is determined that data is input, the process moves to step S32.

[0080] In step S32, the data processing unit 201 performs Figure 4 the processing of the MAC layer as shown, and generates a MAC frame. The data processing unit 201 outputs the MAC frame to the wireless signal processing unit 202.

[0081] In step S33, the wireless signal processing unit 202 performs the transmission process using EDCA. That is, the wireless signal processing unit 202 inputs the MAC frame into the transmission queue according to the access type corresponding to the type of the data. Moreover, the wireless signal processing unit 202 performs carrier sensing to determine the state of the channel, and waits for transmission according to the time specified by the access parameters for each access type. Moreover, if the channel is not being used by other terminals or the like, the MAC frame is converted into a wireless signal and the wireless signal is transmitted.

[0082] In step S34, the wireless signal processing unit 202 obtains the time when the wireless signal is transmitted as the transmission start time. The wireless signal processing unit 202 outputs the transmission start time, the sequence number assigned to the MAC frame, and the access type to which the MAC frame is mapped to the measurement unit 203.

[0083] In step S35, the wireless signal processing unit 202 determines whether an acknowledgment (ACK) is received from the access point 10. In step S35, before the ACK is received, the wireless signal processing unit 202 waits for processing. In step S35, when it is determined that the ACK is received, the process moves to step S36. Although not shown in Figure 10 when there is a retransmission request from the access point 10, the wireless signal processing unit 202 can retransmit the MAC frame. This retransmission can be performed in units of MPDU.

[0084] In step S36, the wireless signal processing unit 202 acquires the time when the ACK is received as the transmission completion time. The wireless signal processing unit 202 outputs the transmission completion time, together with the sequence number assigned to the MAC frame and the access type to which the MAC frame is mapped, to the measurement unit 203.

[0085] In step S37, the measurement unit 203 calculates the delay and the fluctuation for each access type. For example, the delay is calculated based on the time difference between the transmission completion time and the transmission start time. On the other hand, the fluctuation can be calculated, for example, based on the variance with respect to the average value of the delay. The measurement unit 203 outputs the measurement result, together with the access type and the sequence number, to the data processing unit 201.

[0086] In step S38, the data processing unit 201 stores the measurement results of the delay and the fluctuation. Then, the process returns to step S31. The measurement results can be stored, for example, in the storage 26.

[0087] Figure 11 It is a flowchart showing the reporting process in the terminal 20. For example, the reporting process is performed at a constant period such as every hour, every day, or every week. This constant period can be set appropriately. In addition, when the measured value or the statistical value exceeds the threshold set as the request condition through an application or the like, in addition to periodically, the reporting process can be performed immediately.

[0088] In step S41, the data processing unit 201 determines whether to generate a report. For example, when a constant period has elapsed, when a measurement result sufficient to calculate a statistical value is obtained, or when there is a request from the access point 10, it is determined to generate a report. In step S41, when it is determined that no report is generated, the process moves to step S45. In step S41, when it is determined that a report is generated, the process moves to step S42. When a request for report transmission is received from the access point through an Action frame, it can be determined to generate a report. When the delay at the time of sending the previous data frame is applied each time a data frame is sent, etc., it can be set as a trigger for determining to generate a report for sending the data frame.

[0089] In step S42, the data processing unit 201 acquires the measurement results stored in the storage 26, for example, for each access type.

[0090] In step S43, the data processing unit 201 generates Figure 7A or Figure 7B the report shown. As needed, the data processing unit 201 performs statistical processing such as calculating the average value for each access type of the acquired measurement results.

[0091] In step S44, the data processing unit 201 stores the report. The report can be stored, for example, in the storage 26.

[0092] In step S45, the data processing unit 201 determines whether to send a report to the access point 10. For example, when a constant period has elapsed, when the measured value or statistical value exceeds a threshold value that is a request condition set by an application or the like, or when there is a request from the access point 10, it is determined to send a report. In step S45, when it is determined to send a report, the process moves to step S46. In step S45, when it is determined not to send a report, Figure 11 the process ends.

[0093] In step S46, the data processing unit 201 obtains report data from the storage 26, for example. Moreover, the data processing unit 201 performs Figure 4 the processing of the MAC layer as shown, and generates a MAC frame. The data processing unit 201 outputs the generated MAC frame to the wireless signal processing unit 202.

[0094] In step S47, the wireless signal processing unit 202 performs transmission processing using EDCA.

[0095] In step S48, the wireless signal processing unit 202 determines whether an ACK is received from the access point 10. In step S48, before an ACK is received, the wireless signal processing unit 202 waits for processing. In step S48, when it is determined that an ACK is received, Figure 11 the process ends.

[0096] Figure 12 is a flowchart showing the reception processing of the access point 10. In step S51, the wireless signal processing unit 102 determines whether a wireless signal is received. In step S51, when it is determined that a wireless signal is not received, Figure 12 the process ends. In step S51, when it is determined that a wireless signal is received, the process moves to step S52.

[0097] In step S52, the wireless signal processing unit 102 performs reception processing. That is, the wireless signal processing unit 102 demodulates the wireless signal and performs other processing to extract the MAC frame. The wireless signal processing unit 102 outputs the MAC frame to the data processing unit 101. The data processing unit 101 performs MAC layer processing on the MAC frame to restore the data.

[0098] In step S53, the data processing unit 101 determines whether the reception is successful. For example, it can be determined whether the reception is successful by CRC. In step S53, when it is determined that the reception is successful, the process moves to step S54. In step S53, when it is determined that the reception is not successful, the process moves to step S55.

[0099] In step S54, the data processing unit 101 causes the wireless signal processing unit 102 to send an ACK.

[0100] In step S55, the data processing unit 101 causes the wireless signal processing unit 102 to request retransmission of the MAC frame. The retransmission request can also be made in units of MPDUs.

[0101] In step S56, the data processing unit 101 outputs the data to a higher layer such as the application layer. Then, the process returns to step S51.

[0102] Figure 13 It is a flowchart showing the reporting process in the access point 10. For example, the reporting process is performed at regular intervals such as every hour, every day, or every week. This regular interval can be set as appropriate.

[0103] In step S61, the management unit 103 determines whether to request a report. For example, when a constant period has elapsed and there is a need to request a report for RTA delay control, it is determined that a report is requested. In step S61, when it is determined that no report is requested, Figure 13 the process ends. In step S61, when it is determined that a report is requested, the process moves to step S62.

[0104] In step S62, the management unit 103 causes the wireless signal processing unit 102 to request a report.

[0105] In step S63, the wireless signal processing unit 102 performs reception processing. That is, the wireless signal processing unit 102 demodulates the wireless signal and performs other processing to extract the MAC frame. The wireless signal processing unit 102 outputs the MAC frame to the data processing unit 101. The data processing unit 101 performs MAC layer processing on the MAC frame to recover the reported data.

[0106] In step S64, the data processing unit 101 determines whether the reception is successful. In step S64, when it is determined that the reception is successful, the process moves to step S65. In step S64, when it is determined that the reception is not successful, the process moves to step S66.

[0107] In step S65, the data processing unit 101 causes the wireless signal processing unit 102 to send an ACK. The data processing unit 101 outputs the reported data to the management unit 103.

[0108] In step S66, the data processing unit 101 causes the wireless signal processing unit 102 to request retransmission of the MAC frame. The retransmission requirement can also be made in units of MPDUs.

[0109] In step S67, the management unit 103 stores the report. Then, the process returns to step S61. The measurement results can also be stored in the ROM 12, for example.

[0110] As described above, according to the embodiment, the terminal measures at least one of the delay and the fluctuation when transmitting a wireless signal. Further, the terminal transmits a report of data including the measurement result to the access point. Therefore, the access point can grasp the state of the wireless section with the corresponding terminal based on the measurement result recorded in the report. Thereby, the access point can predict whether the request conditions for delay or fluctuation are satisfied before actually inputting RTA traffic, and take countermeasures as needed. For example, in the case where the request conditions are not satisfied, the access point determines not to process the RTA traffic and can reject it when a request for switching of the RTA traffic is received. Alternatively, the access point can also adjust access parameters or the like to satisfy the request conditions. In addition, the access point can also evaluate the reports of multiple terminals (calculate average, variance, etc.) when making these determinations. In this way, in the embodiment, even in the case where there are absolute request conditions for delay and fluctuation, information beneficial for ensuring the request conditions can be provided to the access point.

[0111] [Modification Example]

[0112] Hereinafter, a modification example of the embodiment will be described. The report may have information related to the interference situation in the terminal in addition to the measurement results of the delay or the fluctuation for each access type of the terminal. There is a case where even within the same service area of the access point, depending on the location of the terminal, it is impossible to obtain a transmission opportunity (TXOP) due to the influence of other interference sources, and the delay becomes large. In the case of such a terminal, the delay characteristics deviate. For example, by sending information related to such interference to the access point as a report, the access point can distinguish terminals with larger interference and smaller interference, and thereby, an improvement in the accuracy of the delay characteristics within the service area can be expected.

[0113] When the access point communicates with the terminal, as Figure 14 shown, the access point 10 periodically transmits beacons. The terminal 20 calculates the reception success rate of the beacons from the access point 10 as information for evaluating the interference in the terminal 20. In addition, the terminal 20 calculates the difference between the time (timestamp) stored in the beacon when the access point 10 creates the beacon and the time when the beacon is received as information for evaluating the interference in the terminal 20. The terminal 20 includes this information for evaluating the interference in the report and transmits it to the access point 10. In addition, the information for evaluating the interference in the terminal 20 is not limited to specific information.

[0114] In addition, in the foregoing embodiment and its modification example, the terminal measures at least one of the delay and the fluctuation, and reports the measurement result from the terminal to the access point. Conversely, the access point measures at least one of the delay and the fluctuation, and reports the measurement result from the access point to the terminal. In this case, at the access point, Figure 10 andFigure 11 Processing is performed at the terminal. Figure 12 And Figure 13 Processing. In the case of an access point, the measurement result can be included in a beacon and sent to the terminal.

[0115] In addition, each process according to the above-described embodiment can also be stored as a program to be executed by a processor of a computer. Further, it can be stored in a storage medium of an external storage device such as a magnetic disk, an optical disk, or a semiconductor memory and distributed. Moreover, the processor reads the program stored in the storage medium of the external storage device and controls operations through the read program, thereby being able to execute the above-described processes.

[0116] Description of Reference Numerals

[0117] 1... Communication system

[0118] 10... Access point

[0119] 11... Processor

[0120] 12... ROM

[0121] 13... RAM

[0122] 14... Wireless module

[0123] 15... Router module

[0124] 20... Terminal

[0125] 21... Processor

[0126] 22... ROM

[0127] 23... RAM

[0128] 24... Wireless module

[0129] 25... Display

[0130] 26... Storage

[0131] 101... Data processing unit

[0132] 102... Wireless signal processing unit

[0133] 103... Management unit

[0134] 201... Data processing unit

[0135] 202... Wireless signal processing unit

[0136] 203... Measurement unit.

Claims

1. A terminal, comprising: a measurement unit that measures at least one of a delay when transmitting a wireless signal to an access point and a fluctuation of the wireless signal; a data processing unit that generates information including the result of the measurement; and a wireless signal processing unit that transmits the information to the access point, wherein the measurement unit measures the delay based on the time from when the wireless signal processing unit starts transmitting the wireless signal until a confirmation is received from the access point.

2. The terminal according to claim 1, wherein the measurement unit measures the delay based on the time from when a MAC frame including data of the wireless signal is input to the end of the transmission queue of the wireless signal processing unit until it reaches the front end.

3. The terminal according to claim 1, wherein the measurement unit measures the delay based on the time from when a MAC frame including data of the wireless signal reaches the front end of the transmission queue of the wireless signal processing unit until the wireless signal processing unit transmits the wireless signal.

4. The terminal according to claim 1, wherein the measurement unit measures the delay based on the time from when a retransmission request for the wireless signal is received from the access point until the wireless signal processing unit retransmits the wireless signal.

5. A communication method, comprising: measuring at least one of a delay when transmitting a wireless signal to an access point and a fluctuation of the wireless signal in a terminal; the terminal generating information including the result of the measurement in the terminal; and the terminal transmitting the information to the access point, wherein performing the measurement includes: measuring the delay based on the time from when the terminal starts transmitting the wireless signal until a confirmation is received from the access point.

6. A recording medium, readable by a processor that records a communication program, the communication program causing the processor of a terminal to execute: measuring at least one of a delay when transmitting a wireless signal to an access point and a fluctuation of the wireless signal in a terminal; the terminal generating information including the result of the measurement in the terminal; and the terminal transmitting the information to the access point, wherein performing the measurement includes: measuring the delay based on the time from when the terminal starts transmitting the wireless signal until a confirmation is received from the access point.

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