terminal

Abstract

The terminal of the present invention is provided with: a receiving unit that receives a trigger frame including individual information including a target received power value related to a target value of a received power when an access point receives an uplink response frame (UL response frame); a control unit that estimates a path loss from a transmission power of the trigger frame notified by the trigger frame and a measured received power of the trigger frame, and sets a transmission power of the UL response frame based on the target received power value and the path loss; and a transmission unit that transmits the UL response frame immediately after receiving the trigger frame.

Description

[0001] This application is a divisional application of the invention patent application filed on November 28, 2016, with application number 201680073851.6 and entitled "Communication Device and Communication Method". Technical Field

[0002] This invention relates to a terminal for controlling the transmit power of the uplink. Background Technology

[0003] Within Task Group ax of the IEEE (Institute of Electrical and Electronics Engineers) 802.11 Working Group, the technical specifications for IEEE 802.11ax (hereinafter referred to as 11ax) are being planned and developed as the next standard after 802.11ac. In 11ax, it is anticipated that a multi-user transmission method (hereinafter referred to as MU transmission) based on OFDMA (Orthogonal Frequency-Division Multiple Access) and MU-MIMO (Multi-User-Multi-Input Multi-Output) will be introduced in the uplink (UL).

[0004] During UL MU transmission, the access point (sometimes referred to as the base station) sends control signals to the multiple terminals (sometimes referred to as STAs) it houses as triggers for uplink signals. The terminals transmitting uplink signals send UL response signals (sometimes referred to as UL response frames) to the access point based on the control signals. During UL MU transmission, there are two methods: one where the access point individually designates a terminal to allocate frequency resources (hereinafter referred to as Resource Units (RUs)), and another where the terminal selects an RU based on Random Access (RA). A Trigger Frame (TF) is a control signal that the access point individually designates a terminal to indicate resources, and a Trigger Frame-R (TF-R) is a control signal that the access point indicates at least one resource for random access.

[0005] Furthermore, the TF-R includes allocation information for terminals that secure resources through random access (hereinafter, random access allocation information) and allocation information for terminals that allocate resources individually to specific terminals (hereinafter, individual allocation information). A terminal that sends a UL response signal through random access decodes the RU information for random access from the TF-R, randomly selects one RU from a plurality of random access RUs, and sends a UL response signal using the selected RU (for example, see Non-Patent Document 1).

[0006] Existing technical documents

[0007] Non-patent literature

[0008] Non-patent document 1: IEEE 802.11-15 / 0132r12 "Specification Framework for TGax"

[0009] Non-patent document 2: IEEE 802.11-14 / 1446r0 “Analysis of frequency and power requirements for UL-OFDMA”

[0010] Non-patent document 3: IEEE Std 802.11h-2003

[0011] Non-patent literature 4: 3GPP TS 36.331

[0012] Non-patent document 5: IEEE Std 802.11-2012 Summary of the Invention

[0013] However, in the aforementioned MU transmission, during random access indicated by the Random Access Control Signal (TF-R), the access point side has difficulty determining which terminal secures resources through random access. Therefore, the access point cannot properly set the transmission power of the terminal sending the UL response signal during random access. This leads to problems such as increased received power differences between terminals at the access point, received signals not being contained within the dynamic range of the A / D conversion, or a decrease in SINR (Signal to Interference plus Noise Ratio) due to interference between terminals.

[0014] Therefore, one aspect of the present invention provides a communication method and apparatus that can improve the problems of inter-carrier interference and dynamic range of A / D conversion by effectively controlling the transmission power in the UL response signal sent by the MU during random access, thereby reducing the difference in received power between terminals at the access point.

[0015] One aspect of the communication device of the present invention employs a structure comprising: a target receive power setting unit for setting at least one target receive power value as UL transmit power control information for controlling the uplink transmit power of a plurality of terminals, the target receive power value being a target value of receive power when the plurality of terminals receive uplink signals; a signal generation unit for generating a random access control signal including the at least one target receive power value; and a transmission unit for transmitting the random access control signal.

[0016] Another aspect of the present invention provides a terminal with the following structure: a receiving unit that receives a trigger frame containing separate information, the separate information including a target receive power value related to a target value of receive power when the access point receives an uplink response frame, i.e., a UL response frame; a control unit that estimates path loss by means of the transmit power of the trigger frame as notified by the trigger frame and the measured receive power of the trigger frame, and sets the transmit power of the UL response frame based on the target receive power value and the path loss; and a transmitting unit that transmits the UL response frame immediately after receiving the trigger frame.

[0017] Furthermore, these general or specific methods can be implemented by systems, devices, methods, integrated circuits, computer programs, or recording media, or by any combination of systems, devices, methods, integrated circuits, computer programs, and recording media.

[0018] According to one aspect of the present invention, in the UL response signal transmitted by the MU during random access, the difference in received power between terminals at the access point can be reduced, inter-terminal interference (MU interference) in MU transmission can be reduced, and the received signal can be contained within the dynamic range of A / D conversion.

[0019] Further advantages and effects of one aspect of the invention will become clear from the specification and drawings. These advantages and / or effects can be provided separately by several embodiments and the features described in the specification and drawings, without the need to provide all features in order to obtain one or more of the same features. Attached Figure Description

[0020] Figure 1 A flowchart illustrating the actions of the access point and terminal in Implementation Method 1.

[0021] Figure 2 A block diagram showing the main structure of the access point in Implementation Method 1.

[0022] Figure 3 A block diagram showing the main structure of the terminal in Implementation Method 1.

[0023] Figure 4 A block diagram showing the structure of the access point in Implementation Method 1.

[0024] Figure 5 A block diagram showing the structure of the terminal in Implementation Method 1.

[0025] Figure 6 This diagram illustrates an example of a random access control signal for the transmission power control information and the region setting method 1 of Implementation Method 1.

[0026] Figure 7A This figure shows an example of the target receive power determination method in the target receive power setting method 1 (separate allocation) of the transmit power control information and area setting method 1 of embodiment 1.

[0027] Figure 7B This diagram illustrates an example of the target receive power determination method in the target receive power setting method 2 (separate allocation) of the transmit power control information and area setting method 1 of Embodiment 1.

[0028] Figure 7C This figure illustrates an example of the target receive power determination method in the target receive power setting method 3 (separate allocation) of the transmit power control information and area setting method 1 of Embodiment 1.

[0029] Figure 8A This figure illustrates an example of the allowable power difference based on A / D conversion performance in the transmission power control information and region setting method 1 of Implementation 1.

[0030] Figure 8B This diagram illustrates an example of the allowable power difference based on the number of multiplexing terminals in the transmission power control information and region setting method 1 of Implementation 1.

[0031] Figure 9A This figure shows an example of the target receive power determination method in the target receive power setting method 1 (random access allocation) of the transmit power control information and area setting method 1 of embodiment 1.

[0032] Figure 9B This diagram illustrates an example of the target receive power determination method in the target receive power setting method 2 (random access allocation) of the transmit power control information and area setting method 1 of Implementation Method 1.

[0033] Figure 9C This diagram illustrates the purpose and an example of the target receive power in the target receive power setting method 4 (random access allocation) of the transmit power control information and area setting method 1 in Implementation Method 1.

[0034] Figure 10 This diagram illustrates an example of a random access control signal in the transmission power control information and region setting method 2 of Implementation Method 1.

[0035] Figure 11A This diagram illustrates an example of the target receive power determination method in the target receive power setting method 1' (separate allocation) of the transmit power control information and area setting method 2 in Implementation Method 1.

[0036] Figure 11B This diagram illustrates an example of the target receive power determination method in the target receive power setting method 2' (separate allocation) of the transmit power control information and area setting method 2 in Implementation Method 1.

[0037] Figure 11C This diagram illustrates an example of the target receive power determination method in the target receive power setting method 3' (separate allocation) of the transmit power control information and area setting method 2 in Implementation Method 1.

[0038] Figure 12 This diagram illustrates an example of the target received power value for each response signal category in the transmission power control information and region setting method 3 of Implementation Method 1.

[0039] Figure 13 This diagram illustrates an example of the target received power value for each allocation method in the transmission power control information and region setting method 4 of Implementation Method 1.

[0040] Figure 14 This diagram illustrates an example of a random access control signal in the transmission power control information and region setting method 5 of Implementation Method 1.

[0041] Figure 15 This diagram illustrates an example of the target receive power offset pattern of the transmission power control information and region setting method 5 in Implementation Method 1.

[0042] Figure 16 This diagram illustrates an example of a random access control signal in the transmission power control information and region setting method 6 of Implementation Method 1.

[0043] Figure 17 This diagram illustrates an example of a random access control signal in the transmission power control information and region setting method 7 of Implementation Method 1.

[0044] Figure 18 This is a flowchart illustrating the path loss feedback timing 1 in Implementation Method 1.

[0045] Figure 19 This is a flowchart illustrating the path loss feedback timing 2 in Implementation Method 1.

[0046] Figure 20This is a flowchart illustrating the path loss feedback timing 3 in Implementation Method 1.

[0047] Figure 21 This is a flowchart illustrating the path loss feedback timing 4 in Implementation Method 1.

[0048] Figure 22 A block diagram showing the structure of the terminal in Embodiment 2.

[0049] Figure 23 The diagram illustrates an example of whether the transmission of each response signal category has stopped in the determination method 6 of implementation method 2.

[0050] Figure 24 A block diagram showing the main structure of the access point in Implementation Method 3.

[0051] Figure 25 A diagram illustrating an example of the ULMU transmission process in control method 1 of embodiment 3.

[0052] Figure 26A A diagram illustrating an example of the allowable conditions in method 1 of embodiment 4.

[0053] Figure 26B A diagram illustrating an example of the allowable conditions in method 2 of embodiment 4.

[0054] Figure 26C A diagram illustrating an example of the allowable conditions in method 3 of embodiment 4.

[0055] Figure 27A A diagram showing an example of the range of allowable power values ​​in method 1 for setting the range of allowable power values ​​in embodiment 4.

[0056] Figure 27B A diagram showing an example of the range of allowable power values ​​in method 2 for setting the range of allowable power values ​​in embodiment 4.

[0057] Figure 27C A diagram showing an example of the range of allowable power values ​​in method 3 of embodiment 4, which sets the range of allowable power values.

[0058] Figure 27D A diagram illustrating an example of the range of allowable power values ​​in method 4 of embodiment 4, which sets the range of allowable power values.

[0059] Label Explanation

[0060] 100, 400 access points

[0061] 200, 300 terminals

[0062] 101 Scheduling Unit

[0063] 102 Target Receive Power Setting Unit

[0064] 103 Transmit power control information setting unit

[0065] 104 RA control signal generation unit

[0066] 105, 210 Transmit signal generation unit

[0067] 106, 202 Wireless Transmitter / Receiver Units

[0068] 107, 201 antennas

[0069] 108, 203 Receive signal demodulation unit

[0070] 109 Feedback Information Decoding Unit

[0071] 110 Response Signal Decoding Unit

[0072] 204 RA control signal decoding unit

[0073] 205 Transmit Power Calculation Unit

[0074] 206 Power Control Information Storage Unit

[0075] 207 Path Loss Estimation Unit

[0076] 208 Feedback Information Generation Unit

[0077] 209 Response Signal Generation Unit

[0078] 301, 401 Send Control Unit Detailed Implementation

[0079] (Insights that form the basis of this invention)

[0080] Each of the TF and TF-R includes a common information field (sometimes also called a common field; hereinafter referred to as the "common area") for notifying terminals that have shared control information for transmitting resources to the MU, and a user information field (sometimes also called a STA-specific field or RU-specific field; hereinafter referred to as the "terminal-specific area") for notifying individual control information to each terminal or each RU. The common area includes the trigger type, etc., of the category of the TF notification. Furthermore, the terminal-specific area includes information for identifying the terminal (e.g., AID (Association ID)), MCS (Modulation and Coding Scheme), etc. (e.g., see Non-Patent Document 1).

[0081] Furthermore, multiple TFs and TF-Rs can be continuously transmitted within a TXOP (Transmission Opportunity) (sometimes also referred to as Multiple Trigger Frames in a TXOP). The presence or absence of continuous transmission of TFs and TF-Rs can be explicitly indicated in the cascaded area (sometimes also referred to as the cascaded field) within the TFs and TF-Rs (e.g., see Non-Patent Literature 1).

[0082] In ULMU transmission, issues such as inter-carrier interference and the dynamic range of AD conversion caused by the difference in received power between terminals at the access point are being discussed, and the necessity of controlling the transmit power of each terminal is being addressed (for example, see Non-Patent Literature 2).

[0083] However, regarding uplink transmit power control, while 802.11h defines formats such as TPC report / request, it does not mention specific control methods. The TPC report is included in beacon, probe response, or action frame. The TPC report notifies the transmit power (EIRP: Equivalent Isotopic Radiation Power) and link headroom. Link headroom is control information used to notify of excess quality; terminals receiving link headroom can reduce transmit power by an amount equivalent to the link headroom (e.g., see Non-Patent Document 3).

[0084] Thus, the link margin in the 802.11h transmit power control only indicates excess quality, and therefore does not control to increase transmit power. Consequently, the 802.11h transmit power control is unsuitable as a transmit power control method for addressing the aforementioned issues in UL MU transmission.

[0085] Furthermore, in random access of LTE (Long Term Evolution), RRC (Radio Resource Control) signaling is used to notify the cell of the common target received power value and power ramping. The terminal controls the transmission power to increase by a corresponding power ramp for each retransmission, starting from the initial target received power. The target received power can be changed to semi-static at a minimum interval of 640ms (for example, see Non-Patent Literature 4).

[0086] Thus, in LTE transmit power control methods, due to the long cycle of changing the target receive power value, it is impossible to change the target receive power value based on the combination of terminals allocated resources in each scheduling. That is, in UL MU transmission, even if LTE transmit power control is applied, it is possible to control the target receive power value, such as for terminals located at the cell edge (hereinafter referred to as cell edge terminals), but it is impossible to dynamically control the target receive power value to match the quality of terminals near the access point and terminals at the cell edge far from the access point. Therefore, it is impossible to obtain the gain for optimal adaptive modulation for each terminal based on the scheduling gain, i.e., the receive quality of each terminal in the access point.

[0087] Therefore, in one aspect of the present invention, the objective is to perform efficient transmit power control during UL MU transmission. Specifically, the objective is to introduce efficient transmit power control into the UL response signal for MU transmission via random access, indicated by a random access control signal, thereby reducing the receive power difference between terminals at the access point and improving issues related to inter-carrier interference and the dynamic range of A / D conversion. Furthermore, the objective is to improve system throughput by dynamically changing the target receive power value in each scheduling operation, based on the receive quality of individually allocated terminals and random access allocation, thus enabling instantaneous application of optimal adaptive modulation for each terminal.

[0088] Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings. Furthermore, in each embodiment, the same reference numerals are used for the same structural elements, and are omitted due to repetition in their description.

[0089] (Implementation Method 1)

[0090] [Overview of Communication Systems]

[0091] The communication system of this embodiment includes: an access point (communication device) 100; and a terminal 200. The access point 100 is an access point corresponding to I1ax, and the terminal 200 is a terminal corresponding to I1ax.

[0092] Figure 1 This describes the processing flow in the communication system of this embodiment.

[0093] exist Figure 1 In the process, access point 100 generates a beacon signal (step (hereinafter referred to as "ST") 101).

[0094] The beacon signal includes the transmit power of access point 100. Specifically, the equivalent isotropic radiated power (EIRP) of access point 100 is set in the transmit power. Generally, the broadcast EIRP is determined based on the antenna gain in the maximum radiation direction of the directional antenna. Therefore, when terminal 200 performs path loss estimation and transmit power setting based on the equivalent isotropic radiated power (described later), a difference may occur between the actual received power and the target received power at the access point. To solve this problem, the total radiated power (TRP) of access point 100 can also be used as the broadcast transmit power. By using the total radiated power, the difference in received power caused by the difference between the position and beam direction of terminal 200 can be reduced when beamforming is applied. Furthermore, the transmit power can be broadcast to terminal 200 in management frames such as probe response and association response, or it can be included in the random access control signal to notify terminal 200.

[0095] The generated beacon signal is wirelessly transmitted from access point 100 to terminal 200 (ST102).

[0096] Access point 100 performs scheduling (frequency allocation, MCS selection) of downlink data (DL Data) / UL response signals (ST103). Access point 100 can also use channel quality information (CSI) fed back from terminal 200 for scheduling.

[0097] Based on the scheduling results, access point 100 sets the target receive power value (ST104) for each terminal that has been allocated resources. The method for setting the target receive power value will be described later.

[0098] Access point 100 generates a random access (RA) control signal (TF-R) (ST105).

[0099] The random access control signal includes at least one random access allocation information, and may also arbitrarily include individual allocation information. In the individual allocation information, a unique ID (STA_ID) distinguishing each terminal 200 is used to explicitly indicate the allocation of the RU. That is, each terminal 200 determines the RU assigned its own ID as the RU that can be used in the transmission of the UL response signal. On the other hand, in the random access allocation information, a random access ID is used to explicitly indicate the allocation of the random access RU. As the random access ID, an ID that has not been assigned to distinguish a specific terminal 200 is used. For example, as the STA_ID, a unique ID assigned when associating with the network to which the access point 100 belongs (BSS: Basic Service Set, multiple terminals 200 under access point 100), namely the association ID (AID), can also be used. As the random access ID, a spare value not typically used in the AID can also be used.

[0100] In this embodiment, access point 100 includes a target received power value in the random access control signal. By using the random access control signal to notify the target received power value, access point 100 can dynamically change the target received power value in each scheduling based on the reception quality of the randomly allocated or individually allocated terminals. This allows for the instantaneous application of optimal adaptive modulation to each terminal 200, improving system throughput.

[0101] Furthermore, the target received power value is a power value (target value) that represents the target received power when the access point 100 receives the UL response signals from each terminal 200. Each terminal 200 controls its transmission power to ensure that the received power of the access point 100 is within a specified allowable power difference (±X [dB]) of the target received power value. The allowable power difference is communicated to the terminal 200 from the access point 100 via management frames such as beacons, probe responses, and association responses. By controlling the allowable power difference with management frames, a suitable value can be set for each BSS (Basic Service Set, multiple terminals under the access point). Alternatively, the allowable power difference can also be communicated using random access control signals. By controlling the allowable power difference with each transmission of the random access control signal, appropriate control can be implemented to follow changes in environments where the conditions of the terminal 200 vary greatly, despite increased overhead. Here, the range of upper and lower limits for the allowable power difference based on the target received power value can also be referred to as the allowable power range.

[0102] Furthermore, the target received power value may not be an absolute value of the received power, but rather an offset from a reference value such as the lowest received quality. Additionally, the allowable power difference and the number of notification bits for the target received power value can be changed through random access allocation and individual allocation. In random access, the received power increases significantly in the event of a collision, becoming the main factor causing power differences. Therefore, for example, in the case of random access allocation, by setting a small allowable power difference, the upper limit of the received power in the event of a collision can be suppressed.

[0103] The generated random access control signal is wirelessly notified from access point 100 to terminal 200 (ST106).

[0104] Terminal 200 determines the usable RU (ST107) from among the RUs shown in the random access control signal notified (broadcast) by access point 100, based on its own terminal information. Specifically, if terminal 200 has control information containing its own STA_ID in the terminal-specific area of ​​the random access control signal, it determines that it will be allocated individually. On the other hand, if terminal 200 has control information containing a random access ID but no local STA_ID in the terminal-specific area, and maintains the signal sent for random access, it determines that it will be allocated randomly and selects an RU according to a prescribed process.

[0105] Terminal 200 estimates the path loss (ST108) from the transmit power, antenna gain, etc., as notified by the beacon signal, provided that the RU can be ensured. The path loss estimate is, for example, expressed by Equation (1).

[0106] pathLoss=ApTxPower+ApTxAntGain-StaRxPower…(1)

[0107] In Equation (1), pathLoss is the estimated path loss [dBm], ApTxPower is the transmit power (TRP) [dBm] of the access point 100 notified from beacons, StaRxPower is the receive power [dBm] of the antenna elements of the preamble and data in the terminal 200, and ApTxAntGain is the antenna gain [dB] of the access point 100.

[0108] Antenna gain includes beamforming gain. ApTxAntGain can be notified to terminal 200 from access point 100 using management frames such as beacon, probe response, and association response, or it can be calculated from the number of transmit antennas of access point 100 in terminal 200. Preferably, access point 100 notifies ApTxPower and ApTxAntGain in the same frame, and terminal 200 measures the received power of that frame. In addition, when measuring the received power of the random access control signal, terminal 200 can also calculate the power of the subcarriers included in the RU transmitting the UL response signal and convert it to full-band power as needed. This can reduce errors caused by interference and frequency selectivity. Furthermore, beamforming gain changes depending on the frame and location (Preamble (Legacy or HE, High Efficiency)) or data) used to measure the received power, so the beamforming gain is also changed according to the measurement object. Specifically, beamforming gain is possible in cases where there is no beamforming gain in broadcast frames such as beacons and random access control signals, in non-HT duplicate PPDUs with backward compatibility with the legacy method, and in cases with a legacy preamble for a single address frame; beamforming gain is possible in cases following the HE preamble for a single address frame. By considering beamforming gain, the accuracy of path loss estimation is improved when measuring the portion following the HE preamble. Received power is either the received power of the signal immediately preceding it or the average received power.

[0109] Furthermore, when the terminal 200 estimates the path loss from a signal for which beamforming is not applicable (e.g., a random access control signal), it can treat ApTxAntGain in equation (1) as beamforming gain and ignore this term, using the following equation (2). Moreover, even when the terminal 200 estimates the path loss from a beamforming-effective signal, if the transmit power ApTxPower is EIRP, since beamforming gain is included in ApTxPower, the following equation (2) can also be used.

[0110] pathLoss=ApTxPowe-StaRxPower…(2)

[0111] Terminal 200 generates UL response signals (e.g., data, transmit buffer status report, or DL ​​Data request signals) sent by MU during random access (ST109).

[0112] Terminal 200 sets the transmission power of the UL response signal (ST110) using the estimated path loss and the target received power value contained in the random access control signal. Furthermore, the path loss is the path loss estimated from the downlink signal (the signal from access point 100 to terminal 200). That is, based on the reversibility of the uplink and downlink propagation paths, the path loss of the downlink signal is used as the path loss for calculating the transmission power of the UL response signal (the signal from terminal 200 to access point 100). The transmission power of the UL response signal is calculated, for example, according to equation (3). Furthermore, if the transmission power exceeds the maximum permissible transmission power of terminal 200, or is below the minimum transmission power, terminal 200 transmits the UL response signal at the maximum or minimum transmission power.

[0113] StaTxPower = α·pathLoss + P target +StaTxAntGain+10log 10 (RUsize)+C…(3)

[0114] In equation (3), StaTxPower is the transmit power [dBm] set by terminal 200, pathLoss is the path loss [dBm] estimated according to equation (1) or equation (2), α is the correction coefficient multiplied by the path loss, and P target This is the target received power value [dBm] notified by the random access control signal, StaTxAntGain is the antenna gain [dB] of terminal 200, and RUsize is the size of the allocated RU. Furthermore, C is an environment-dependent correction constant, set according to the surrounding OBSS (Overlapping BSS) conditions, etc. Moreover, P... target It is the received power in the antenna element.

[0115] The path loss correction factor α can be broadcast from access point 100 to terminal 200 via management frames such as beacons, probe responses, and association responses, or it can be included in the random access control signal and notified to terminal 200. By controlling the correction factor α with management frames, a suitable value can be set for each BSS. Furthermore, by controlling the correction factor α with each transmission of the random access control signal, appropriate control can be performed to keep up with changes in environments where the terminal's condition varies greatly, despite increased overhead.

[0116] For example, in an OBSS environment with densely configured BSSs, the path loss correction factor α is set considering the interference generated by the BSSs. For instance, when there are many surrounding BSSs, the path loss correction factor α is set to a small value (e.g., 0.8) to reduce interference to the surrounding BSSs by suppressing the transmission power of the cell edge terminal. On the other hand, when there are few surrounding BSSs, the path loss correction factor α is set to a large value (e.g., 1.0) to increase the throughput of the cell edge terminal by increasing its transmission power.

[0117] Terminal 200 sends a UL response signal to access point 100 (ST111) at a set transmission power.

[0118] The above describes the processing flow in the communication system of this embodiment.

[0119] Figure 2 This is a block diagram of the main structure of the access point 100 in this embodiment. Figure 2 In the access point 100 shown, the transmit power control information setting unit 103 sets the transmit power control information for each resource based on the target receive power value obtained from the target receive power setting unit 102 and the resource allocation information (individual allocation, random access allocation, etc.) obtained from the scheduling unit 101. The RA control signal generation unit 104 generates a random access control signal (TF-R) that includes allocation information representing at least one transmit frequency resource. The random access control signal includes the target receive power value calculated by the transmit power control information setting unit 103. The wireless transmit / receive unit 106 transmits the random access control signal.

[0120] Figure 3 This is a block diagram of the main structure of the terminal 200 in this embodiment. The wireless transmission / reception unit 202 receives a random access control signal (TF-R) containing allocation information for at least one transmission frequency resource. Here, one of a plurality of random access IDs is allocated to each of the at least one transmission frequency resource. The TF-R control signal decoding unit 204 obtains the target received power value contained in the random access control signal. In the path loss estimation unit 207, the path loss is estimated based on the transmission power notified from the access point 100 and the received power of the received signal. The transmission power calculation unit 205 sets the transmission power of the response signal using the target received power value and the path loss.

[0121] [Structure of Access Point 100]

[0122] Figure 4 This is a block diagram illustrating the structure of access point 100 in this embodiment. Figure 4In this configuration, access point 100 includes a scheduling unit 101, a target receive power setting unit 102, a transmit power control information setting unit 103, an RA control signal generation unit 104, a transmit signal generation unit 105, a wireless transmit / receive unit 106, an antenna 107, a receive signal demodulation unit 108, a feedback information decoding unit 109, and a response signal decoding unit 110. Furthermore, the scheduling unit 101, the target receive power setting unit 102, the transmit power control information setting unit 103, and the RA control signal generation unit 104 constitute an access control (MAC) unit, while the transmit signal generation unit 105, the receive signal demodulation unit 108, the feedback information decoding unit 109, and the response signal decoding unit 110 constitute a baseband (BB) processing unit.

[0123] The scheduling unit 101 determines the RU allocation and MCS for each terminal 200 based on the CSI and buffer status report fed back from each terminal 200. These terminals 200 are the terminals 200 for which resources are allocated by the access point 100, and therefore are individually allocated terminals. On the other hand, the scheduling unit 101 ensures the RU for random access when it is necessary to allocate resources to the terminal 200 for random access.

[0124] The target receive power setting unit 102 sets the target receive power value for each RU according to the RU allocation status of the scheduling unit 101. The target receive power setting unit 102 sets at least one target receive power value as UL transmit power control information for controlling the uplink transmit power of each of the multiple terminals 200. Details of the method for setting the target receive power value in the target receive power setting unit 102 will be described later.

[0125] The transmit power control information setting unit 103 generates transmit power control information for each RU from the target receive power value determined by the target receive power setting unit 102 and resource allocation information representing the scheduling result determined by the scheduling unit 101. Details of the control information set by the transmit power control information setting unit 103 will be described later. Furthermore, the scheduling unit 101 may also perform rescheduling actions such as MCS reselection based on the transmit power control information calculated by the transmit power control calculation unit 103.

[0126] The RA control signal generation unit 104 generates a random access control signal for transmitting a UL response signal requested by the terminal 200. The random access control signal includes the trigger type (common area) of the notification control signal category, terminal identification information (terminal-specific area), and MCS (terminal-specific area). In the terminal identification information, a unique ID (STA_ID) is set to distinguish the terminal 200 in the case of individual allocation, and a random access ID is set in the case of random access allocation. Furthermore, the random access control signal includes transmission power control information set by the transmission power control information setting unit 103. Additionally, the random access control signal includes at least one target receive power value. Details regarding the set transmission power control information and the area (common area or terminal-specific area) will be described later.

[0127] The transmit signal generation unit 105 encodes and modulates the random access control signal input from the RA control signal generation unit 104. Furthermore, the transmit signal generation unit 105 encodes and modulates information indicating the transmit power of the access point 100 and information indicating the transmit antenna gain of the access point 100. Then, the transmit signal generation unit 105 adds control signals (also called preambles) for frequency synchronization, timing synchronization pilot signals, channel estimation signals, etc., in the modulated signal to the receiving side (terminal 200), generates a radio frame (transmit signal), and outputs it to the wireless transmit / receive unit 106.

[0128] The wireless transmission and reception unit 106 performs prescribed wireless transmission processing, such as D / A conversion and up-conversion to carrier frequency, on the signal input from the transmission signal generation unit 105, and transmits the processed signal through the antenna 107.

[0129] Upon receiving a UL response signal (a response signal to a random access control signal sent by the access point 100) and feedback information from the terminal 200, the access point 100 operates as follows.

[0130] The wireless signal received by antenna 107 is input to wireless transmission and reception unit 106. Wireless transmission and reception unit 106 applies prescribed wireless reception processing, such as down-conversion of carrier frequency, to the wireless signal, and outputs the processed signal to reception demodulation unit 108.

[0131] The receiving signal demodulation unit 108 extracts the received wireless frames by applying autocorrelation processing to the signal input from the wireless transmitting and receiving unit 106, and outputs them to the feedback information decoding unit 109 and the response signal decoding unit 110.

[0132] The feedback information decoding unit 109 demodulates and decodes the CSI and path loss fed back from the terminal 200 in the wireless frame input from the received signal demodulation unit 108, and outputs it to the scheduling unit 101.

[0133] The response signal decoding unit 110 demodulates and decodes the UL response signal contained in any of the RUs indicated by the control signal in the radio frame input from the received signal demodulation unit 108. The response signal decoding unit 110 outputs the reception result to the scheduling unit 101. The scheduling unit 101 performs retransmission control, etc., based on the reception result.

[0134] [Structure of Terminal 200]

[0135] Figure 5 This is a block diagram illustrating the structure of the terminal 200 in this embodiment. Figure 5 In this terminal 200, there are an antenna 201, a wireless transmission and reception unit 202, a received signal demodulation unit 203, a RA control signal decoding unit 204, a transmit power calculation unit 205, a power control information storage unit 206, a path loss estimation unit 207, a feedback information generation unit 208, a response signal generation unit 209, and a transmit signal generation unit 210. Furthermore, the transmit power calculation unit 205, the power control information storage unit 206, the path loss estimation unit 207, the feedback information generation unit 208, and the response signal generation unit 209 constitute an access control unit (MAC), and the received signal demodulation unit 203, the RA control signal decoding unit 204, and the transmit signal generation unit 210 constitute a baseband (BB) processing unit.

[0136] The wireless transmitting and receiving unit 202 receives signals from access point 100 via antenna 201. Figure 4 The wireless transmission and reception unit 202 performs prescribed wireless reception processing, such as down-conversion and A / D conversion, on the received signal and outputs the processed signal to the received signal demodulation unit 203, while outputting information indicating the received power to the power control information storage unit 206. Furthermore, the wireless transmission and reception unit 202 performs prescribed wireless transmission processing, such as D / A conversion and up-conversion to carrier frequency, on the signal input from the transmission signal generation unit 210 (described later), and transmits the processed signal through the antenna 201.

[0137] The receive signal demodulation unit 203 extracts the received wireless frames by performing autocorrelation processing on the signals input from the wireless transmit / receive unit 202, and outputs them to the RA control signal decoding unit 204. Furthermore, the receive signal demodulation unit 203 outputs information contained in the extracted wireless frames, representing the transmit power and transmit antenna gain of the access point 100, to the power control information storage unit 206.

[0138] The RA control signal decoding unit 204 demodulates and decodes the random access control signal contained in the transmission RU of the random access control signal in the radio frame input from the received signal demodulation unit 203, outputs the transmission power control information to the transmission power calculation unit 205, and outputs the information required for the generation of transmission signals such as MCS to the transmission signal generation unit 210.

[0139] The power control information storage unit 206 stores information indicating the received power input from the wireless transmit / receive unit 202, and information indicating the transmit power and transmit antenna gain of the access point 100 input from the receive signal demodulation unit 203.

[0140] The path loss estimation unit 207 calculates the path loss using Equation (1) or Equation (2) based on the transmit power of the access point 100 (further, transmit antenna gain in Equation (1)) input from the power control information storage unit 206 and the measured receive power, and outputs the result to the transmit power calculation unit 205 and the feedback information generation unit 208.

[0141] The transmit power calculation unit 205 calculates the transmit power of the UL response signal based on the target received power value contained in the transmit power control information input from the RA control signal decoding unit 204 and the path loss input from the path loss estimation unit 207, for example, using equation (3).

[0142] Feedback information generation unit 208 generates feedback information, including estimated channel quality information (CSI, RSSI) and path loss input from path loss estimation unit 207, as needed, and outputs it to transmission signal generation unit 210. The timing of the feedback path loss will be described later.

[0143] The response signal generation unit 209 generates a UL response signal that includes the terminal ID of the terminal 200 and the transmission information of the terminal 200 (data, transmission buffer status notification or DL ​​Data request, etc.), and outputs it to the transmission signal generation unit 210.

[0144] The transmit signal generation unit 210 uses information such as the MCS input from the RA control signal decoding unit 204 to encode and modulate the UL response signal input from the response signal generation unit 209 or the feedback information input from the feedback information generation unit 208. Then, the transmit signal generation unit 210 adds control signals (prefixes) such as pilot signals for frequency synchronization and timing synchronization and channel estimation signals for the receiving side (access point 100) to the modulated signal, generates a radio frame (transmit signal), and outputs it to the wireless transmit / receive unit 202.

[0145] [Methods for sending power control information and setting regions]

[0146] Next, the area set by the transmission power control information and random access control signal for the aforementioned access point 100 will be explained in detail.

[0147] The following sections describe the methods for setting the transmission power control information and the region, 1 to 7.

[0148] <Setup Method 1>

[0149] In setting method 1, access point 100 (RA control signal generation unit 104) configures the target received power value in the terminal-specific area of ​​the random access control signal. Figure 6 This represents an example of a random access control signal for setting method 1. Figure 6 The trigger type indicates the category of the trigger frame, so for example, the trigger type can be set to random access control signal.

[0150] After receiving the random access control signal, terminal 200 obtains the target receive power value configured in the terminal-specific area where the STA_ID or random access ID of terminal 200 (the local machine) is set in the terminal identification ID. Then, terminal 200 calculates the transmit power of the response signal from the path loss calculated by path loss estimation unit 207 and the target receive power value obtained above, for example by equation (3), and performs transmit power control on the response signal.

[0151] [How to set the target received power value]

[0152] Next, the method for setting the target received power value in access point 100 when setting method 1 is applied will be explained. Furthermore, the target received power value is the received power value in the antenna element. Therefore, when determining the target received power value from the received power including the received antenna gain, after the target received power value is determined, access point 100 needs to correct it to a value after removing the received antenna gain and notify terminal 200.

[0153] The following uses Figures 7A to 7C Methods for setting the target received power value when allocating power separately are explained in sections 1 to 3.

[0154] <Target Receive Power Setting Method 1 (Individual Allocation)>

[0155] The target receive power setting unit 102 determines the target receive power value based on the terminal information representing the resources allocated through individual allocation, as determined by the scheduling unit 101, and the MCS of each terminal 200, and on the difference in the minimum required receive power of each MCS among the resources. Furthermore, the minimum required receive power (Minimum sensitivity) of each MCS is defined in the 802.11 specification (for example, refer to Non-Patent Document 5 in the case of 11n).

[0156] Figure 7A This illustrates an example of a target received power determination method within the target received power setting method 1 (separate allocation) of setting method 1. Figure 7A In this process, resources (RU=1, 2, 3) are allocated to the three terminals (ID=1, 2, 3). Furthermore, the MCS for each terminal is #2, #3, and #5, respectively.

[0157] The target received power setting unit 102 sets an offset such that the difference between the maximum and minimum received power, plus each offset (offset 1 to 3), for the minimum required received power of each MCS is contained within the allowable power difference. For example, in Figure 7A In the middle, the target receiving power setting unit 102 sets each offset so that the difference between the minimum required receiving power of MCS#5 (which has the largest minimum required receiving power among MCS#2, #3, and #5) plus offset3 and the minimum required receiving power of MCS#2 (which has the smallest minimum required receiving power) plus offset1 is included within the allowable power difference.

[0158] In this way, by setting the target receive power value for each terminal 200 that has been allocated resources based on the minimum required receive power of each MCS, access point 100 can set the necessary minimum transmit power, thereby reducing the power consumption of terminal 200 and the interference to other access points 100.

[0159] Furthermore, Figure 8A As shown, the allowable power difference can also be changed according to the A / D conversion performance of access point 100. By changing the allowable power difference according to the A / D conversion performance of access point 100, the receiving performance of terminal 200 caused by the receiving power difference can be prevented from deteriorating, and the target receiving power value can be flexibly set, thereby improving the scheduling gain.

[0160] also, Figure 8BAs shown, the allowable power difference can also be changed according to the number of multiplexed terminals in OFDMA / MU-MIMO. When the number of multiplexed terminals is small, the receive power difference between terminals is more likely to be smaller compared to when the number of multiplexed terminals is large. Therefore, by changing the allowable power difference according to the number of multiplexed terminals, the target receive power value can be flexibly set, and the scheduling gain can be improved.

[0161] <Target Receive Power Setting Method 2 (Separate Allocation)>

[0162] The target receive power setting unit 102 determines the target receive power value based on the difference in receive power of the signals previously received by the terminal 200, from the terminal information determined by the scheduling unit 101, which indicates that resources have been allocated through individual allocation.

[0163] Figure 7B This illustrates an example of a target received power determination method within the target received power setting method 2 (separate allocation) of method 1. Figure 7B In the process, the target receiving power setting unit 102 assumes that the scheduling unit 101 has allocated resources to three terminals (ID=1, 2, 3), and sets an offset (offset1~3) based on the difference in receiving power of the signals previously received from the terminal, so that the power difference is contained within the allowable power difference.

[0164] In this way, by setting the target received power value based on the received power of previously received signals, access point 100 can suppress fluctuations in the target received power value of each terminal 200.

[0165] Furthermore, similar to target receiver power setting method 1 (individual allocation), such as Figure 8A , Figure 8B As shown, the allowable power difference can also be changed based on the A / D conversion performance and the number of multiplexing terminals in OFDMA / MU-MIMO.

[0166] <Target Receive Power Setting Method 3 (Separate Allocation)>

[0167] The target receive power setting unit 102 uses terminal information determined by the scheduling unit 101, which indicates that resources have been allocated through individual allocation, to calculate the estimated receive power from the maximum transmit power and path loss of the terminal, and determines the target receive power value based on the difference in estimated power between terminals allocated to each resource.

[0168] Figure 7C This illustrates an example of a target received power determination method within target received power setting method 3 (separate allocation) in method 1. Figure 7CIn this context, the target received power setting unit 102 assumes that the scheduling unit 101 has allocated resources to the three terminals (ID = 1, 2, 3), and sets offsets (offset 1 to 3) to ensure that the estimated received power difference between the terminals 200 is within the allowable power difference range. Furthermore, Figure 7C This is an example where the maximum transmit power of each terminal 200 is equal. For example, the target receive power setting unit 102 uses the value contained in the association request signal as the maximum transmit power of the terminal 200.

[0169] In this way, by setting the target receive power value based on the maximum transmit power and path loss of each terminal 200, access point 100 can prevent setting a target receive power value that requires a transmit power exceeding the maximum transmit power that the terminal 200 can set.

[0170] Furthermore, similar to target receiver power setting method 1 (individual allocation), such as Figure 8A , Figure 8B As shown, the allowable power difference can also be changed depending on the A / D conversion performance or the number of multiplexing operations in OFDMA / MU-MIMO.

[0171] Next, in the following, use Figures 9A to 9C Methods for setting the target received power value during random access allocation are explained in sections 1 to 4.

[0172] <Target Receive Power Setting Method 1 (Random Access Allocation)>

[0173] The target receive power setting unit 102 sets the average value of the target receive power values ​​of each terminal that has been allocated resources through individual allocation as the target receive power value of the random access allocation RU.

[0174] Figure 9A This example illustrates the target reception power determination method in Target Reception Power Setting Method 1 (Random Access Allocation) within Setting Method 1. Terminals with IDs 1 and 2 are terminals whose resources were allocated through individual allocation, and ID 0 is a resource for random access. Furthermore, for example, it is assumed that the target reception power values ​​for the resources with IDs 1 and 2 are determined using one of the target reception power setting methods 1 to 3 (Individual Allocation). In this case, the target reception power setting unit 102 calculates the target reception power of the resource for random access (ID = 0) from the average of the target reception power values ​​of the resources with IDs 1 and 2.

[0175] In this way, the average value of the target received power of each terminal that has been allocated resources through individual allocation is set by the access point 100 as the target received power of the random access allocation RU, which can reduce the difference in received power between the randomly allocated terminal and the individually allocated terminal.

[0176] <Target Receive Power Setting Method 2 (Random Access Allocation)>

[0177] The target receive power setting unit 102 sets the minimum value of the target receive power value of each terminal that has been allocated resources through individual allocation as the target receive power value of the random access allocation RU.

[0178] Figure 9B This example illustrates the target reception power determination method of target reception power setting method 2 (random access allocation) in setting method 1. Terminals 200 with IDs 1 and 2 are terminals whose resources are allocated through individual allocation, and ID 0 is a resource for random access. Furthermore, it is assumed that the target reception power value of the resources with IDs 1 and 2 is determined by one of the target reception power setting methods 1 to 3 (individual allocation). The target reception power setting unit 102 selects the lowest value of the target reception power value of the resources with IDs 1 and 2 (...). Figure 9B The target received power value of the resource (ID=0) used for random access is calculated using the target received power value of the resource with ID=2.

[0179] In this way, by setting the minimum target received power value of each terminal whose resources are allocated individually to the target received power value of the random access allocation RU, access point 100 can prevent the difference in received power between the randomly access allocation terminal and other terminals from increasing, even if the received power of random access increases. This is because the reason for increasing the received power of random access is that, in access point 100, it is possible to receive signals from multiple terminals 200 simultaneously due to collisions.

[0180] <Target Received Power Setting Method 3 (Random Access Allocation)>

[0181] The target receive power setting unit 102 sets the average receive power of previously received signals from all or a portion of the terminals connected to the access point 100 as the target receive power value.

[0182] It is impossible to determine which terminal 200 will actually send a response signal in the random access allocation. Therefore, the average received power of the signals previously received by all or a portion of the terminals connected to the access point 100 is set as the target received power value. In the random access allocation, the transmission power required to meet the target received power value is easily contained within the range between the minimum and maximum transmission power of each terminal 200.

[0183] <Target Receive Power Setting Method 4 (Random Access Allocation)>

[0184] The target receiving power setting unit 102 sets a fixed value of target receiving power according to the purpose.

[0185] Figure 9C This section illustrates the purpose and target receive power value of target receive power setting method 4 (random access allocation) in setting method 1. For example, to prioritize receiving signals from cell edge terminals, target receive power setting unit 102 lowers the target receive power value (e.g., -75dBm) so that the required target receive power is met even at cell edge terminals. On the other hand, to prioritize receiving signals from terminals near the access point, target receive power setting unit 102 raises the required target receive power value (e.g., -65dBm).

[0186] In this way, by setting the target receiving power value of the randomly accessed terminal according to the purpose, the access point 100 can give priority to the reception of the cell edge terminal or the terminal near the access point.

[0187] The above explains the method for setting the target received power value in setting method 1.

[0188] In this way, in setting method 1, access point 100 notifies terminal 200 of the target received power value in the terminal-specific area of ​​the random access control signal. Furthermore, terminal 200 performs transmit power control of the response signal based on the estimated path loss and the notified target received power value. This reduces the received power difference among access points 100 where resources are allocated via the random access control signal, improving issues related to inter-carrier interference and the dynamic range of A / D conversion. Moreover, by setting the target received power value for each terminal 200 in its separate area, access point 100 can match the transmit power to the channel quality of each terminal 200.

[0189] <Setup Method 2>

[0190] In setting method 2, access point 100 (RA control signal generation unit 104) configures the target received power value in the common area of ​​the random access control signal. Figure 10 This represents an example of a random access control signal for setting method 2. Figure 10 The trigger type in the context indicates the type of trigger frame. For example, the trigger type is set to random access control signal.

[0191] After receiving the random access control signal, terminal 200 obtains the target received power value configured in the terminal common area. Then, terminal 200 calculates the transmission power of the response signal from the path loss calculated by path loss estimation unit 207 and the target received power value obtained above, for example, using equation (3), and performs transmission power control on the response signal.

[0192] Furthermore, in this example configuration, since the target received power value is the same for each terminal 200, the reception quality of each terminal 200 is approximately the same. Access point 100 can uniquely determine the MCS of each terminal 200 based on the common target received power value. Therefore, it is also possible to configure the system so that information such as the MCS is transmitted in a common area instead of in individual terminal areas. By transmitting the MCS in a common area, the overhead of control signals for random access can be reduced.

[0193] [How to set the target received power value]

[0194] Next, the method for setting the target received power value in access point 100 when setting method 2 is applied will be explained.

[0195] The following uses Figures 11A to 11C The methods for setting the target receiving power when allocating power separately are explained in sections 1' to 3'.

[0196] <Target Receive Power Setting Method 1' (Individual Allocation)>

[0197] The target receive power setting unit 102 determines the target receive power value based on the terminal information and MCS of each terminal, which are determined by the scheduling unit 101 and represent the resources allocated through individual allocation. The minimum required receive power is based on the highest MCS.

[0198] Figure 11A This illustrates an example of the target received power determination method in method 1' (separate allocation) of method 2. Figure 11A In this process, resources (RU=1, 2, 3) are allocated to the three terminals (ID=1, 2, 3). Furthermore, the MCS for each terminal (ID=200) is #2, #3, and #5 respectively.

[0199] The target receive power setting unit 102 adds a certain offset value to the minimum required receive power of the highest MCS among the MCS#2, #3 and #5 of each terminal 200, namely the MCS#5 of terminal ID=3, and sets it as the common target receive power value among each terminal 200.

[0200] In this way, by setting a common target receive power value for all terminals 200 based on the highest MCS among the MCS set for each terminal 200, access point 100 can increase the possibility of receiving the response signals of all terminals without errors.

[0201] <Target Received Power Setting Method 2' (Separate Allocation)>

[0202] The target receive power setting unit 102 determines the target receive power value based on the average receive power of the signals previously received by the terminal 200, from the terminal information determined by the scheduling unit 101, which indicates that resources have been allocated through individual allocation.

[0203] Figure 11B This illustrates an example of a target received power determination method in method 2' (separate allocation) of the target received power setting method 2. Figure 11B In this context, the target received power setting unit 102 assumes that the scheduling unit 101 has allocated resources to the three terminals 200 (ID=1, 2, 3), and sets the average value of the received power of the signals previously received by the terminal 200 as the common target received power value among the terminals 200.

[0204] In this way, by setting the average value of the received power of the signals previously received from the terminal 200 as the target received power value, the transmission power required to meet the target received power value can be easily contained within the range between the minimum and maximum transmission power of each terminal 200.

[0205] <Target Received Power Setting Method 3' (Individual Allocation)>

[0206] The target receive power setting unit 102 uses terminal information determined by the scheduling unit 101, which indicates that resources have been allocated through individual allocation, to calculate the estimated receive power from the maximum transmit power and path loss of the terminal 200, and determines the estimated receive power of the terminal 200 with the lowest estimated receive power as the common target receive power value among all terminals 200.

[0207] Figure 11C This illustrates an example of a target received power determination method in method 3' (separate allocation) of method 2. Figure 11C In this context, the target receiving power setting unit 102 assumes that the scheduling unit 101 has allocated resources to the three terminals 200 (ID=1, 2, 3), and sets the estimated receiving power of the terminal 200 with the lowest estimated receiving power, i.e., terminal ID=3, as the common target receiving power value among all terminals 200.

[0208] In this way, access point 100 estimates the target receive power based on the maximum transmit power and path loss of each terminal 200, and sets the target receive power of the terminal 200 with the lowest target receive power as the common target receive power value for all terminals 200. This allows the target receive power to be set low, reducing the power consumption of the terminal 200 and interference to other access points 100. Furthermore, it prevents the setting of a target receive power value that requires exceeding the maximum transmit power that the terminal 200 can set.

[0209] Next, the method for setting the target receive power value during random access allocation will be explained below.

[0210] <Target Receive Power Setting Method (Random Access Allocation)>

[0211] The target reception power setting unit 102 can also set the target reception power value, which is the same as the target reception power setting methods 1' to 3' (individual allocation) in setting method 2 described above, as the target reception power value for random access allocation RU, which is a common target reception power value set for each terminal 200 that has been allocated resources through individual allocation. Furthermore, the target reception power setting unit 102 can also set the target reception power value using the same setting methods as the target reception power setting methods 3 (random access allocation) and 4 (random access allocation) in setting method 1.

[0212] The above explains the method for setting the target received power value in setting method 2.

[0213] Thus, in setting method 2, access point 100 is accessed via... Figure 10 Configuring the target receive power value within the common area of ​​the random access control signals can shorten the time length of individual terminal areas and reduce the overhead of the random access control signals. Access point 100 cannot determine which of the random access allocation terminals 200 will send a response signal, and therefore cannot individually set the optimal value of the target receive power value for each terminal 200. Thus, even when the proportion of random access allocation terminals 200 is large, performance degradation is minimal when configuring the target receive power value within the common area.

[0214] <Setup Method 3>

[0215] In setting method 3, the access point 100 (RA control signal generation unit 104) is configured with a target receiving power value in the common area of ​​the random access control signal, similar to setting method 2. However, the target receiving power value is set to a different value for each category of response signal (information) transmitted in random access.

[0216] As categories of response signals, for example, enumerable data, control information, management information, etc. Figure 12 This is an example of setting the target received power value for each category of response signal using method 3. The target received power value is set higher when the importance of the response signal is high, and lower when the importance of the response signal is low. Figure 12 In this context, the order of control information, data, and management information indicates the highest priority.

[0217] Furthermore, a higher target received power value means, for example, adding a ZdB offset to the target received power value calculated using setting method 2. Similarly, a lower target received power value means, for example, adding a YdB offset to the target received power value calculated using setting method 2 (where Y... <Z)。

[0218] Furthermore, for example, a response signal with high importance is one whose value is frequently updated, while a response signal with low importance is one whose value is not frequently updated.

[0219] Furthermore, the categories of response signals may not be the so-called data, control information, and management information classifications. Instead, for example, management information can be further subdivided to notify each probe response and association response of the target received power value.

[0220] After receiving a random access control signal, terminal 200 acquires multiple target receive power values ​​configured in the terminal common area and switches the target receive power value to be used based on the type of signal transmitted as a response signal. Then, terminal 200 calculates the transmission power of the response signal from the path loss calculated by path loss estimation unit 207 and the selected target receive power value, for example using equation (3), and performs transmission power control for the response signal.

[0221] Thus, in setting method 3, access point 100 is... Figure 10 The target received power value is configured in the common area of ​​the control signals used for random access, and a different target received power value is set for each category of response signal. Therefore, in random access, even in the event of conflicting response signals, at access point 100, the probability of correctly receiving a response signal with a high target received power value is higher, thus increasing the success rate of receiving signals of higher importance.

[0222] <Setup Method 4>

[0223] In setting method 4, the target received power value is configured in the common area of ​​the random access control signal, similar to setting method 2. However, the target received power value is notified separately for each individually allocated and randomly allocated point.

[0224] Figure 13This is an example illustrating the target received power value for each allocation method in method 4. In the case of individual allocation, no conflict occurs with the response signal, or the maximum and minimum transmission power of the terminal 200 allocating resources to access point 100 can be predicted in advance. Therefore, the difference between the received power of the response signal actually received by access point 100 and the target received power value is considered small. Therefore, access point 100 sets the target received power value more efficiently in the case of individual allocation.

[0225] On the other hand, when the allocation method is random access allocation, collisions of the response signals may occur. Due to these collisions, the difference between the received power of the response signal and the target received power value increases. That is, the probability that the received power of the response signal is considered to exceed the target received power value is high. Therefore, when the allocation method is random access allocation, access point 100 sets the target received power value lower.

[0226] After receiving a random access control signal, terminal 200 acquires multiple target receive power values ​​configured in the terminal common area. Terminal 200 uses the terminal identification ID in its individual area to determine whether the resource used in transmitting the response signal is allocated through random access. That is, if the terminal identification ID is its own ID, terminal 200 determines it is individually allocated; if it is a random access ID, it determines it is randomly allocated. Terminal 200 switches the target receive power value used in transmitting the response signal based on whether the allocation method is individually allocated or randomly allocated. Then, terminal 200 calculates the transmission power of the response signal using the path loss calculated by path loss estimation unit 207 and the selected target receive power value, for example, using equation (3), and performs transmission power control for the response signal.

[0227] Thus, in setting method 4, access point 100 is... Figure 10 The target received power value is configured in the common area of ​​the random access control signal shown, and a different target received power value is set for each allocation method (individual allocation, random access allocation). Thus, for example, in the case of random access allocation, the received power increases in the event of a collision. Therefore, by setting a target received power value that takes into account the increase in received power caused by a collision in the random access allocation, access point 100 can prevent the degradation of A / D conversion performance and the increase in interference to other terminals in the event of a collision.

[0228] <Setup Method 5>

[0229] In setting method 5, access point 100 configures a target received power value in the common area of ​​the random access control signal. Furthermore, access point 100 configures an offset value (target received power offset) from the target received power value set in the common area in a separate area of ​​the terminal.

[0230] Figure 14 This is an example of a control signal used to set up random access in method 5. Figure 14 The trigger type in the context indicates the type of trigger frame. For example, the trigger type is set to random access control signal.

[0231] After receiving a random access control signal, terminal 200 acquires the target received power value configured in the terminal common area. Furthermore, terminal 200 acquires the target received power offset configured in a terminal-specific area where the STA_ID or random access ID of terminal 200 (the local machine) is set as the terminal identification ID, and adds the target received power offset to the target received power value acquired from the common area. Then, terminal 200 calculates the transmission power of the response signal using, for example, Equation (3), based on the path loss calculated by path loss estimation unit 207 and the target received power value with the added target received power offset, and performs transmission power control on the response signal.

[0232] [How to set the target received power value]

[0233] Next, the method for setting the target received power value in access point 100 when setting method 5 is applied will be explained.

[0234] Figure 15 This is an example of a pattern for setting the target received power offset in method 5. Figure 15 This represents the offset value when the target received power offset is shown in 2 bits. Furthermore, if the target received power offset value is a number of bits less than the target received power value, it can be any number of bits.

[0235] The target received power value when using setting method 5 is calculated using the same steps as in setting method 1. However, unlike setting method 1, where the target received power value set individually for each terminal 200 is set in a terminal-specific region of the random access control signal, in setting method 5, the access point 100 calculates, for example, the average of the target received power values ​​obtained for each terminal 200 and sets the average value in a common region of the random access control signal. Furthermore, the access point 100 measures the difference between the target received power value and the average value for each terminal 200, using... Figure 15 The table quantizes the difference between the target received power value and the averaged target received power value, generating a target received power offset, which is set in a separate area of ​​the terminal.

[0236] Thus, in setting method 5, access point 100 is... Figure 14 The target received power value is configured in the common area of ​​the random access control signal shown, and an offset value from the target received power value set in the common area is configured in the terminal-specific area. In this way, the number of bits of the target received power offset is less than the number of bits of the target received power value, so when there are a large number of terminals, the total time length of the common area and the terminal-specific area can be shortened, and the overhead of the random access control signal can be reduced.

[0237] <Setup Method 6>

[0238] In setting method 6, access point 100 sets different transmit power control information for individually allocated terminals and randomly allocated terminals in the terminal-specific area of ​​the random access control signal. As an example, for individually allocated terminals, access point 100 configures a transmit power value for transmitting uplink signals in the terminal-specific area, and for randomly allocated terminals, it configures a target receive power value in the terminal-specific area.

[0239] Figure 16 This is an example of a control signal used to set up random access in method 6. Figure 16 The trigger type in the context indicates the type of trigger frame. For example, the trigger type is set to random access control signal.

[0240] Access point 100 configures a transmit power value in the area where a separate control signal for the allocation of a terminal's individual area is set, that is, in the area where a unique ID (STA_ID) is set to distinguish the terminal 200. On the other hand, access point 100 configures a target receive power value in the area where a control signal for the allocation of random access in a terminal's individual area is set, that is, in the area where a random access ID (RA_ID) is set.

[0241] After receiving a random access control signal, if there is a terminal-specific region where the STA_ID of terminal 200 is set as the terminal identification ID, terminal 200 obtains the transmission power value configured in the corresponding terminal-specific region and performs transmission power control on the response signal based on the obtained transmission power. On the other hand, if there is a terminal-specific region where the random access ID is set as the terminal identification ID, terminal 200 obtains the target reception power value configured in the corresponding terminal-specific region, calculates the transmission power of the response signal from the path loss calculated by the path loss estimation unit 207 and the obtained target reception power value, for example, using equation (3), and performs transmission power control on the response signal.

[0242] [How to set the target received power value]

[0243] Next, the method for setting the target received power value in the access point 100 when setting method 6 is applied will be explained. Similar to setting method 1, the access point 100 calculates the target received power value for each terminal 200.

[0244] In the case of setting method 6, access point 100 needs to set the transmission power for the individually allocated terminal, so for example, using equation (3), the transmission power of terminal 200 is calculated. Then, access point 100 sets the calculated transmission power value in the terminal-specific area of ​​the random access control signal for the individually allocated terminal. Furthermore, the format (number of bits) of the target receive power value and the transmit power value can also be the same.

[0245] In this way, without notifying the terminal 200 of the transmit antenna gain, where the transmit antenna gain has a significant impact, transmit power control can be performed more accurately by calculating the transmit power for the individually allocated terminal from the access point 100. Furthermore, by notifying the individually allocated terminal of the transmit power, path loss calculation and transmit power calculation can be omitted on the terminal 200 side, thus reducing the power consumption of the terminal 200. Moreover, since the format (number of bits) of the transmit power value and the target receive power value is the same, the position of the terminal identification ID remains unchanged, so the complexity of determining the position of the terminal identification ID does not increase.

[0246] <Setup Method 7>

[0247] In setting method 7, access point 100 configures a target receive power value for the random access allocation terminal in the common area of ​​the random access control signal, and configures a target receive power value for the individually allocated terminal in the terminal-specific area of ​​the random access control signal.

[0248] Figure 17 This is an example of a control signal used to set up random access in method 7. Figure 17 The trigger type indicates the category of the trigger frame; for example, the trigger type is set to random access control signal. Access point 100 configures the target receive power value in a terminal-specific area that is assigned a unique ID (STA_ID) to distinguish terminal 200, but does not configure the target receive power value in a terminal-specific area that is assigned a random access ID (RA_ID). Furthermore, access point 100 configures the target receive power value for random access allocation terminals in the common area.

[0249] After receiving a random access control signal, if there is a terminal-specific region where the STA_ID of terminal 200 is set as the terminal identification ID, terminal 200 obtains the target received power value configured in the corresponding terminal-specific region and performs transmission power control of the response signal based on the obtained target received power value. On the other hand, if the STA_ID of terminal 200 is not set as the terminal identification ID, terminal 200 obtains the target received power value configured in the common region, calculates the transmission power of the response signal from the path loss calculated by the path loss estimation unit 207 and the obtained target received power value, for example, using equation (3), and performs transmission power control of the response signal.

[0250] Thus, in setting method 7, as follows Figure 17 As shown, access point 100 configures the target received power value in the common area for the random access control signal for randomly allocated terminals, and configures the target received power value in the terminal-specific area for the random access control signal for individually allocated terminals. This shortens the combined time of the common area and the terminal-specific area when there are many randomly allocated terminals, reducing the overhead of the random access control signal. Furthermore, access point 100 cannot determine which terminal 200 among the randomly allocated terminals sends the response signal, and cannot set the optimal value of the target received power value for each terminal 200 individually. Therefore, even with a large proportion of randomly allocated terminals 200, performance degradation is minimal when the target received power value is configured in the common area.

[0251] The above describes the methods 1 to 7 for setting the transmission power control information and the region in this embodiment.

[0252] [Path Loss Feedback Timing]

[0253] Next, the timing of the path loss feedback from the terminal 200 to the access point 100 when the path loss is used when the access point 100 calculates the target received power value will be explained in this embodiment.

[0254] The timing of the feedback path loss of terminal 200 is explained in sections 1 to 4 below.

[0255] <Timer 1>

[0256] In time 1, terminal 200 sends a path loss notification signal to access point 100 as a response to a request signal (path loss request signal) from access point 100. Figure 18 This is an example of the path loss feedback processing flow for time 1.

[0257] exist Figure 18In this process, access point 100 generates a beacon signal (ST201). The beacon signal contains the transmission power of access point 100.

[0258] The generated beacon signal is wirelessly transmitted from access point 100 to terminal 200 (ST202).

[0259] Next, access point 100 periodically generates path loss request signals (ST203). For example, the path loss request signal is generated as an action frame. The action frame is a frame used to set measurement requests, TPC requests, etc. (see, for example, non-patent document 3).

[0260] The generated path loss request signal is wirelessly notified from access point 100 to terminal 200 (ST204).

[0261] Upon receiving a path loss request signal, terminal 200 estimates the path loss from the transmit power, antenna gain, etc., as notified by the beacon signal (ST205). For example, the path loss estimate is expressed by equation (1) or equation (2).

[0262] Next, terminal 200 generates a path loss notification signal (ST206). For example, the path loss notification signal is generated as an action frame.

[0263] The generated path loss notification signal is wirelessly transmitted from terminal 200 to access point 100 (ST207).

[0264] Thus, in time 1, terminal 200 sends a path loss request signal to access point 100 as a response to the path loss request. In this way, terminal 200 can notify access point 100 of the path loss request at regular intervals.

[0265] <Timer 2>

[0266] In timing 2, terminal 200 periodically estimates path loss and sends a path loss notification signal to access point 100 when the change in path loss since the timing of the last path loss notification reaches a certain benchmark, or when a certain amount of time has elapsed since the timing of the last path loss notification. Figure 19 This is an example of the path loss feedback processing flow for time 2.

[0267] exist Figure 19 In this process, access point 100 generates a beacon signal (ST211). The beacon signal contains the transmission power of access point 100.

[0268] The generated beacon signal is wirelessly transmitted from access point 100 to terminal 200 (ST212).

[0269] Terminal 200 periodically estimates path loss (ST213) based on the transmit power notified via beacon signals and the antenna gain. For example, the path loss estimate is expressed as Equation (1) or Equation (2). The signal used in the path loss estimate can also be a signal received just before the path loss estimate.

[0270] Terminal 200 determines whether the estimated path loss has changed since the timing of the last path loss notification has reached a certain benchmark, or whether a certain amount of time has elapsed since the timing of the last path loss notification.

[0271] If the determination conditions are met, the terminal 200 generates a path loss notification signal (ST215). For example, the path loss notification signal is generated as an action frame.

[0272] The generated path loss notification signal is wirelessly transmitted from terminal 200 to access point 100 (ST216).

[0273] Thus, in timing 2, terminal 200 only notifies access point 100 of the path loss at the timing when the path loss changes. This reduces the overhead of control information.

[0274] <Timer 3>

[0275] In timing 3, terminal 200 determines the access point 100 to be connected, and when sending the association request signal, the path loss estimated by terminal 200 is included in the association request signal. Figure 20 This is an example of the path loss feedback processing flow for time 3.

[0276] exist Figure 20 In this process, access point 100 generates a beacon signal (ST221). The beacon signal contains the transmission power of access point 100.

[0277] The generated beacon signal is wirelessly communicated from access point 100 to terminal 200 (ST222).

[0278] Terminal 200 selects access point 100 (ST223) to connect to from factors such as reception quality.

[0279] Terminal 200 estimates the path loss (ST224) from the transmit power and antenna gain notified by the beacon signal. For example, the path loss estimate is expressed as Equation (1) or Equation (2).

[0280] Terminal 200 generates an association request signal (ST225). The association request signal is a signal used to notify terminal 200 of information regarding the access point 100 to the destination (e.g., see Non-Patent Document 5). Terminal 200 also includes the estimated path loss in the association request signal.

[0281] The generated association request signal is wirelessly notified from terminal 200 to access point 100 (ST226).

[0282] Thus, in timing 3, by including path loss in the associated request signal, the overhead of control information can be reduced compared to sending path loss separately.

[0283] <Timer 4>

[0284] In timing 4, when sending a buffer status report, terminal 200 includes the path loss estimated by terminal 200 in the buffer status report as a response to the random access control signal. Figure 21 This is an example of the path loss feedback processing flow for timing 4.

[0285] exist Figure 21 In this process, access point 100 generates a beacon signal (ST231). The beacon signal contains the transmission power of access point 100.

[0286] The generated beacon signal is wirelessly transmitted from access point 100 to terminal 200 (ST232).

[0287] In order to confirm the buffer status of terminal 200, access point 100 generates a random access control signal (ST233) for requesting a buffer status report.

[0288] The generated random access control signal is wirelessly notified from access point 100 to terminal 200 (ST234).

[0289] Terminal 200 estimates the path loss (ST235) from the transmit power and antenna gain notified by the beacon signal. For example, the path loss estimate is expressed by equation (1) or equation (2).

[0290] Terminal 200 generates a buffer status report (ST236) to notify the local machine of the buffer status. Terminal 200 also includes the estimated path loss in the buffer status report.

[0291] The generated buffer status report is wirelessly notified from access point 100 to terminal 200 (ST237).

[0292] Thus, in timing 4, the buffer status report and path loss are sent simultaneously via terminal 200. Compared to sending the path loss separately, this reduces the overhead of control information. Furthermore, the buffer status report and path loss are used for random access scheduling and transmit power control. Because they are used at the same time, simultaneous feedback is highly efficient.

[0293] The above explains the timing of path loss feedback 1 to 4.

[0294] Thus, in this embodiment, access point 100 notifies terminal 200 of the target received power value using a random access control signal. Terminal 200 calculates the transmit power based on the estimated path loss and the notified target received power value, and performs transmit power control. Therefore, when access point 100 receives signals multiplexed by multiple terminals 200 via UL MU-MIMO or OFDMA, the receive power difference between terminals 200 can be reduced. This reduces MU interference and brings the received signal within the dynamic range of A / D conversion. Therefore, according to this embodiment, by efficiently performing transmit power control on the UL response signal transmitted by the MU during random access, the receive power difference between terminals 200 is reduced, thus improving the problems of inter-carrier interference and the dynamic range of A / D conversion.

[0295] Furthermore, in this embodiment, by notifying the target received power value using a random access control signal, the target received power value can be dynamically changed in each scheduling based on the received quality of randomly allocated terminals or individually allocated terminals, allowing for instantaneous application of optimal adaptive modulation for each terminal 200. Through these methods, the system throughput can be improved in this embodiment.

[0296] (Implementation Method 2)

[0297] As mentioned above, by using random access control signals to notify the target receive power value of the terminal through the access point, and performing transmit power control on the terminal side, when the access point receives signals that have been multiplexed from multiple terminals in the form of UL MU-MIMO or OFDMA, the receive power difference between terminals in the access point can be reduced.

[0298] However, terminals corresponding to 11ax have limited transmit power control capabilities. For example, some terminals corresponding to 11ax may only allow for a few levels of transmit power adjustment, while others may lack transmit power control functionality altogether. Therefore, even though the transmit power is calculated from the notified target receive power value, limitations on the terminal's maximum transmit power, minimum transmit power, and the variable range of transmit power may prevent the transmission of a response signal from meeting the target receive power value at the access point.

[0299] Therefore, this embodiment describes a method for controlling the terminal's transmission when it is difficult to meet the target received power value due to limitations in the terminal's maximum transmission power, minimum transmission power, and the variable range of transmission power. This reduces the difference in received power between terminals at access points.

[0300] Figure 22 This is a block diagram illustrating the structure of the terminal 300 in this embodiment. Figure 22 Zhongyu Figure 5 The difference lies in that the information output by the transmit power calculation unit 205 and the information output by the RA control signal demodulation unit 204 are input to the transmit control unit 301, and the output of the transmit control unit 301 is input to the wireless transmit / receive unit 202. Furthermore, regarding the structure of the access point 100, it differs from that of Embodiment 1 (…). Figure 4 )same.

[0301] In this embodiment, the transmission control unit 301 controls the wireless transmission and reception unit 202 to cancel signal transmission based on the calculated transmission power value, which differs from embodiment 1 (details will be described later).

[0302] The transmit power calculation unit 205 calculates the transmit power using equation (3) based on the target received power value input from the RA control signal decoding unit 204 and the path loss value input from the path loss estimation unit 207.

[0303] The transmission control unit 301, based on the transmission power value input from the transmission power calculation unit 205, information input from the RA control signal decoding unit 204 (target receive power value, etc.), and the maximum transmission power, minimum transmission power, and transmission power variable amplitude of the terminal 300, determines whether the transmission of the signal has stopped from the viewpoint of whether the transmission power can be set within the allowable power difference of the target receive power value, and outputs information indicating whether transmission has stopped to the wireless transmission and reception unit 202. Furthermore, the method for determining whether transmission has stopped will be described later.

[0304] When the wireless transmission and reception unit 202 receives a transmission stop instruction from the transmission control unit 301, it does not transmit the corresponding signal. On the other hand, when the wireless transmission and reception unit 202 does not receive a transmission stop instruction from the transmission control unit 301, it performs prescribed wireless transmission processing on the signal input from the transmission signal generation unit 210, such as D / A conversion and up-conversion to carrier frequency, and transmits the processed signal through the antenna 201.

[0305] The following sections explain methods 1 through 6 for determining whether sending has stopped.

[0306] <Judgment Method 1>

[0307] In determination method 1, the transmission control unit 301 does not issue a transmission stop indication at any transmission power.

[0308] Thus, in determination method 1, the transmission control unit 301 does not issue a transmission stop instruction. Therefore, if there are many terminals 300 that cannot be set to a transmission power within the allowable power difference to meet the target received power value due to transmission power limitations, the power difference of the received signal in access point 100 may exceed the specified value. However, when the number of terminals is small, the possibility of the received power difference being contained within the specified range increases. Therefore, by not issuing a transmission stop instruction, the transmission control unit 301 can make efficient use of resources. Furthermore, when the A / D conversion performance of access point 100 is high, there is no problem with the dynamic range of A / D conversion caused by the transmission power difference.

[0309] <Judgment Method 2>

[0310] In determination method 2, if the transmission control unit 301 cannot set the transmission power within the allowable power difference that satisfies the target received power value as the transmission power calculated by the transmission power calculation unit 205 due to the limitations of the maximum transmission power, minimum transmission power, and variable transmission power of the terminal 300, the transmission control unit 301 instructs the transmission to stop.

[0311] In this way, the transmission control unit 301 will always stop transmitting if it cannot set a transmission power within the allowable power difference that satisfies the target received power value of the terminal 300. This prevents the received power difference between the terminals 300 from increasing to the point where the target received power value cannot be met. In addition, by stopping the transmission of signals that may fail to be received due to not meeting the target received power value, the collision rate of random access allocation can be reduced.

[0312] <Judgment Method 3>

[0313] In determination method 3, the transmission control unit 301 does not issue a transmission stop instruction at any transmission power level under the condition of individual allocation. On the other hand, under the condition of random access allocation, if the transmission control unit 301 cannot set a transmission power within the allowable power difference that satisfies the target received power value due to the limitations of the maximum transmission power, minimum transmission power, and variable transmission power range of the terminal 300, it instructs to stop transmission.

[0314] In this way, in the random access allocation at access point 100, where terminal 300 cannot determine which terminal 300 is actually sending a response signal (i.e., without knowing the transmission power control capabilities of terminal 300 such as maximum and minimum transmission power), it only instructs the terminal 300 that may have a target receive power value set at access point 100 to stop transmission based on its transmission power. This prevents the difference in receive power between terminals 300 from increasing and failing to meet the target receive power value. On the other hand, in individual allocation, at access point 100, the target receive power value can be set considering the transmission power control capabilities of the terminal 300 allocating resources, such as maximum and minimum transmission power. Therefore, the target receive power value changes less drastically due to transmission power limitations, and in individually allocated terminals, a response signal is always sent regardless of the transmission power, improving resource utilization efficiency.

[0315] <Judgment Method 4>

[0316] In determination method 4, if the maximum transmission power, minimum transmission power, and variable transmission power range of terminal 300 prevent setting a transmission power within the allowable power difference to satisfy the target received power value, a signaling instruction is sent from access point 100 to terminal 300 to determine whether transmission should be stopped. Terminal 300 then specifies whether transmission should be stopped based on the signaling instruction (0: do not transmit, 1: transmit).

[0317] In this way, the terminal 300 can change the transmission control based on the signaling from the access point 100 by switching whether to stop transmission when the transmission power cannot be set within the allowable power difference to meet the target received power value, and can also change the transmission control based on the A / D conversion performance of the access point 100.

[0318] <Judgment Method 5>

[0319] In determination method 5, the transmission control unit 301 does not issue a transmission stop instruction even at any transmission power in the case of individual allocation. However, in the case of random access allocation, based on the BSS LOAD notified by beacons, if the transmission power cannot be set within the allowable power difference to satisfy the target received power value due to limitations on the maximum transmission power, minimum transmission power, and variable transmission power amplitude of the terminal 300, the transmission control unit 301 indicates a transmission stop. That is, the transmission control unit 301 does not issue a transmission stop instruction when the BSS LOAD is low, and issues a transmission stop instruction when the BSS LOAD is high. BSS LOAD is information provided by the access point 100 to the terminal 300 via beacons regarding the number of terminals connected to the BSS and the congestion level corresponding to the traffic volume (for example, see Non-Patent Document 5).

[0320] In this way, the terminal 300 switches between sending and receiving stops during random access allocation based on the BSS LOAD. For signals that may fail to be received due to not meeting the target received power value, and in cases where the probability of collisions in random access is high (i.e., when the BSS LOAD is high), sending stops can reduce the probability of collisions in random access.

[0321] <Judgment Method 6>

[0322] In determination method 6, the transmission control unit 301 does not issue a transmission stop indication in any transmission power under the case of individual allocation, and switches between transmission stop and no transmission stop according to each category of response signal in the case of random access allocation.

[0323] As categories of response signals, for example, enumerable data, control information, management information, etc. Figure 23 This example illustrates the determination method 6 based on the category of the response signal to determine whether transmission has stopped. In the case of a response signal category with high importance, the transmission control unit 301 does not issue a transmission stop instruction at any transmission power. On the other hand, in the case of a response signal category with low importance, if the transmission control unit 301 cannot set a transmission power within the allowable power difference to satisfy the target received power value due to limitations of the terminal 300's maximum transmission power, minimum transmission power, and transmission power variable amplitude, it instructs the transmission to stop.

[0324] In this way, by switching between sending and receiving stop during random access allocation based on the type of response signal, terminal 300 can prevent the inability to send high-importance signals during random access. Furthermore, the operation of the sending stop indication is not limited to completely stopping transmission. For example, by suppressing the probability of sending random access signals, a lower priority operation can also be performed.

[0325] The above describes methods 1 to 6 for determining whether transmission has stopped in the transmission control unit 301.

[0326] Furthermore, the switching of the aforementioned determination method can be broadcast from access point 100 to terminal 300 using management frames such as beacons, probe responses, and association responses, or it can be included in random access control signals and communicated to terminal 300. By controlling with management frames, appropriate values ​​can be set for each BSS. Moreover, although control is performed with each transmission of random access control signals, while increasing overhead, appropriate control can be implemented to keep pace with changes in the state of terminal 300, even in environments where the status of terminal 300 fluctuates significantly.

[0327] Thus, in this embodiment, if the terminal 300 is unable to transmit a UL response signal at the target received power notified by the access point 100 due to limitations in its transmission power control capabilities (performance), such as the maximum transmission power, minimum transmission power, and variable transmission power range of the terminal 300, the transmission control unit 301 stops the transmission processing of the terminal 300 according to the situation. Therefore, regardless of the performance of the terminal 300, i.e., the limitations in its maximum transmission power, minimum transmission power, and variable transmission power range, the difference in received power between the terminals 300 in the access point 100 can be reduced. Therefore, according to this embodiment, MU interference can be reduced, the received signal can be contained within the dynamic range of the A / D conversion, and the system throughput can be improved.

[0328] (Implementation Method 3)

[0329] As mentioned earlier, by stopping the transmission of response signals that cannot meet the target receiving power based on the situation, the difference in receiving power between terminals in the access point can be reduced, regardless of the terminal's performance. However, by stopping transmission, depending on the target receiving power value set, the number of terminals that may send response signals may increase significantly.

[0330] Therefore, in this embodiment, a method is described to prevent a significant reduction in the transmission opportunities of response signals from specific terminals, such as terminals with low transmission power control capabilities, by changing the target receive power value in each transmission when continuously transmitting random access control signals.

[0331] Figure 24 This is a block diagram showing the structure of access point 400 in this embodiment. Figure 24 Zhongyu Figure 4The difference lies in that the resource allocation information determined by the scheduling unit 101 and the target receiving power value calculated by the target receiving power setting unit 102 are input to the transmission control unit 401, and the transmission control unit 401 outputs instruction control information to the scheduling unit 101 and the target receiving power setting unit 102. Furthermore, regarding the structure of the terminal 300, it differs from embodiment 2 (…). Figure 22 )same.

[0332] In this embodiment, the operation of the scheduling unit 101 and the target receiving power setting unit 102 for each transmission count when the transmission control unit 401 continuously transmits the random access control signal is different from that in embodiment 1 (details will be described later).

[0333] In the transmission control unit 401, the resource allocation information determined by the scheduling unit 101 and the target receive power value calculated by the target receive power setting unit 102 are input. The transmission control unit 401 stores the input resource allocation information (including MCS) and target receive power value for each transmission of the random access control signal.

[0334] When transmitting continuous random access control signals, the transmission control unit 401 controls the target receive power value included in the random access control signals. Specifically, when continuously transmitting random access control signals, the transmission control unit 401 controls the scheduling unit 101 and the target receive power setting unit 102 based on the target receive power value and resource allocation information previously notified to the terminal 300 via the random access control signals, so as to set different target receive power values ​​and resource allocation information for each transmission cycle. Furthermore, the control method in the transmission control unit 401 will be described later.

[0335] The scheduling unit 101 determines resource allocation based on the instructions from the transmission control unit 401 and outputs resource allocation information to the transmission power control information setting unit 103 and the RA control signal generation unit 104. The target reception power setting unit 102 determines the target reception power value based on the instructions from the transmission control unit 401 and outputs the target reception power value to the transmission power control information setting unit 103.

[0336] Figure 25 An example of the UL MU transmission process during continuous transmission of the random access control signal (TF-R) in Implementation 3.

[0337] exist Figure 25In the ULMU transmission process within the TXOP interval of access point 400 (AP) which has obtained transmission rights via CSMA / CA, TF-R#1 is the first transmitted random access control signal, and TF-R#2 is the second transmitted random access control signal. Furthermore, in Figure 25 In this context, UL MU is the UL response signal, and ACK (or M-BA (Multi-STA Block ACK)) indicates successful reception of the UL response signal. Furthermore, in... Figure 25 In this context, P1 and P2 are the target received power values ​​for each transmission count.

[0338] Furthermore, continuous transmission means that the random access control signal is transmitted continuously within the TXOP. After obtaining the transmission right via CSMA / CA, the access point 400 counts the number of transmissions. In addition, the access point 400 uses one of the target receive power setting methods (random access allocation) of Embodiment 1 to set the target receive power value applicable to the first transmitted random access control signal (TF-R#1).

[0339] The control methods 1 to 3 of the transmission control unit 401 are described below.

[0340] <Control Method 1>

[0341] In control method 1, when continuously transmitting random access control signals, the transmission control unit 401 controls the reduction of the target receive power value of the random access allocation terminal at each transmission. Furthermore, as the transmission control unit 401 reduces the target receive power with each transmission of the random access control signal, it also reduces the MCS level of the response signal (i.e., changes it to a lower transmission speed MCS). The MCS level can also be uniquely set based on the target receive power value.

[0342] For example, the transmission control unit 401 applies target reception power setting method 1 (random access allocation) in calculating the target reception power value P1 notified by the first transmitted random access control signal. Then, the transmission control unit 401 reduces the target reception power value P2 notified by the second transmitted random access control signal from the first notified target reception power P1 by 10 dB (P2 = P1 - 10 [dB]). Preferably, this difference between different target reception powers is determined based on the value of the allowable power difference. For example, the allowable power difference can be set to ±5 dB, and the change in the target reception power value can be set to 10 dB.

[0343] In this way, during the continuous transmission of the random access control signal, the transmission control unit 401 reduces the target receive power value and the MCS level with each transmission. That is, the access point 400 (transmission control unit 401) performs a UL MU-MIMO / OFDMA transmission process with a target receive power value P2 (< P1) immediately after the UL MU-MIMO / OFDMA transmission process with the random access control signal specifying the target receive power value P1.

[0344] Therefore, in the first random access control signal, since the target received power value is high, even if the terminal 300 cannot send a response signal due to the maximum transmit power limit, it can still send a response signal in the second random access control signal, where the target received power value of the reduced received power is below the maximum transmit power of the terminal 300.

[0345] That is, it can prevent a significant reduction in the transmission opportunities of response signals from specific terminals 300, such as those at the cell edge. Furthermore, by changing the target received power value based on the allowable power difference, it can also provide transmission opportunities for terminals that do not have transmit power control functions.

[0346] In addition, control method 1 can also be applied to control the suppression of access by terminals 300 at the cell edge by using a first random access control signal and the suppression of access by terminals 300 near the access point by using a second random access control signal.

[0347] <Control Method 2>

[0348] In control method 2, the transmission control unit 401 increases the allowable power difference with each transmission while continuously transmitting random access control signals. For example, the transmission control unit 401 sets a target receive power value according to target receive power setting method 1 (random access allocation). Furthermore, the transmission control unit 401 accommodates terminals 300 that average power with a smaller allowable power difference when the first random access control signal is transmitted. Then, by increasing the allowable power difference when the second random access control signal is transmitted, the transmission control unit 401 can accommodate terminals 300 that were unable to respond to the signal due to the first random access control signal.

[0349] In this way, when continuously transmitting random access control signals, the transmission control unit 401 increases the permissible power difference with each transmission of the random access control signal. As a result, the permissible power difference of the target received power value increases with each transmission, so even if a terminal 300 was unable to transmit a response signal during a previous transmission due to limitations of maximum transmission power, minimum transmission power, and the variable amplitude of transmission power, it can still transmit a response signal in a subsequent transmission. That is, it is easy to transmit a response signal from a terminal 300 whose target received power value, generated by a large difference between the target received power value specified by the access point 400 and the transmission power that the terminal 300 can transmit, each time.

[0350] <Control Method 3>

[0351] In control method 3, similar to control method 1, the transmission control unit 401 reduces the target received power value and MCS for each transmission during the continuous transmission of the random access control signal. Furthermore, the transmission control unit 401 increases the PPDU length of each transmitted UL MU.

[0352] In this way, during the continuous transmission of the random access control signal, by reducing the target receive power value and MCS level for each transmission and increasing the PPDU length, in addition to achieving the same effect as control method 1, it is also possible to make the amount of information that can be transmitted using the first UL response signal and the second UL response signal equal. That is, the inequality between the terminal 300 transmitting with the first UL response signal and the terminal 300 transmitting with the second UL response signal can be eliminated.

[0353] Furthermore, the tiered reduction of the target received power value, as described below, also improves the efficiency of time resource utilization and latency characteristics. Specifically, when the target received power value is low, the terminal 300 with a margin in the link budget (i.e., the terminal 300 with a power margin for path loss) may reduce its transmission power to transmit. In this case, compared to using a low-speed MCS at the maximum transmittable speed, a longer transmission time is required for the same amount of data. In contrast, in this embodiment, by first setting a large target received power value, the possibility of the high-speed transmission terminal 300 transmitting the response signal with a high-speed MCS and a shorter PPDU without reducing its speed is increased. As a result, the efficiency of time resource utilization and the transmission latency can be improved.

[0354] The above describes control methods 1 to 3 for the transmission control unit 401.

[0355] Furthermore, continuous transmission is not limited to transmission within the TXOP interval where transmission rights are pre-obtained. Within the cascaded field (also called the cascaded area) included in the random access control signal, the interval where the random access control signal is continuously transmitted (the interval marked "1" in the cascaded field) can also be considered as the continuous transmission interval. Moreover, the transmission control unit 401 can perform transmission control even if there are three or more consecutive transmissions.

[0356] Thus, in this embodiment, when the random access control signal is continuously transmitted, the transmission control unit 401 performs actions to reduce the target receive power value and MCS level for each consecutive transmission. This prevents a significant reduction in the transmission opportunities for response signals from terminals with low transmit power control capabilities, such as terminal 300, or specific terminals 300.

[0357] (Implementation Method 4)

[0358] In 11ax, there are two types of terminal classes (also known as STA Classes) with different accuracy requirements for parameters such as transmit power setting accuracy and RSSI measurement accuracy. Class A terminals are high-function terminals, and the transmit power (absolute value) setting accuracy is required to be within ±3dB. That is, Class A terminals allow a maximum setting error of 3dB for the transmit power indicated by the access point. On the other hand, Class B terminals are low-function terminals, and the transmit power (absolute value) setting accuracy is required to be within ±9dB. That is, Class B terminals allow a maximum setting error of 9dB for the transmit power indicated by the access point.

[0359] As mentioned above, from the perspective of whether the terminal's transmit power can be set to meet the condition of being within the allowable power difference from the target received power value, it is determined whether there is a signal transmission halt and the transmission of the response signal is stopped. This reduces MU interference and keeps the received signal within the dynamic range of the A / D conversion. Furthermore, it can improve system throughput. In this embodiment, from the perspective of whether the terminal's transmit power can be set to meet the transmit power condition based on the allowable condition of the target received power set by the access point, it is determined whether there is a signal transmission prohibition.

[0360] Therefore, in this embodiment, when it is difficult to meet the allowable conditions by limiting the maximum transmission power, minimum transmission power, and variable transmission power of the terminal, the difference in receiving power between terminals in the access point can be reduced by prohibiting the terminal from transmitting.

[0361] Regarding the structure of terminal 300, and implementation method 2 ( Figure 22 The structure of access point 100 is the same as in implementation 1. Figure 4 )same.

[0362] The transmit power calculation unit 205 calculates the transmit power value using equation (3) based on the target received power value input from the RA control signal decoding unit 204 and the path loss value input from the path loss estimation unit 207.

[0363] The transmission control unit 301 determines whether a transmission power value satisfying the allowable conditions can be set based on the transmission power value input from the transmission power calculation unit 205, information input from the RA control signal decoding unit 204 (such as the target receive power value), and the maximum transmission power, minimum transmission power, and transmission power variable amplitude of the terminal 300. Then, if a transmission power value satisfying the allowable conditions cannot be set, the transmission control unit 301 generates a transmission prohibition message. Thus, the transmission control unit 301 determines whether a transmission power value satisfying the allowable conditions can be set; if it cannot be set, it outputs the transmission prohibition message to the wireless transmission and reception unit 202. Furthermore, details regarding the method for setting the allowable conditions will be described later.

[0364] When the wireless transmission and reception unit 202 receives a transmission prohibition message from the transmission control unit 301, it does not transmit the signal input from the transmission signal generation unit 210. On the other hand, when the wireless transmission and reception unit 202 does not receive a transmission stop message from the transmission control unit 301, it performs prescribed wireless transmission processing on the signal input from the transmission signal generation unit 210, such as D / A conversion and up-conversion to carrier frequency, and transmits the processed signal through the antenna 201.

[0365] The following uses Figures 26A-26C Methods 1 to 3 for setting the allowable conditions are explained respectively.

[0366] <Method 1 for setting allowable conditions>

[0367] Figure 26AThis is an example of the allowable condition setting method in allowable condition setting method 1. In allowable condition setting method 1, by limiting the terminal's maximum transmission power, minimum transmission power, and variable transmission power amplitude, when the terminal cannot transmit a response signal using the transmission power value calculated by equation (3), the terminal estimates the received power value at the access point if it transmits a response signal with the actual transmitable transmission power value. Then, even if the terminal sets the transmission power value to the maximum transmission power value, if the estimated received power value at the access point is lower than the lower limit of the allowable power range set based on the target received power value, the terminal's transmission is prohibited. Furthermore, even if the terminal sets the transmission power value to the minimum transmission power value, if the estimated received power value at the access point still exceeds the upper limit of the allowable power range, the terminal's transmission is prohibited. In addition, if the interval (step) of the transmit power values ​​that the terminal can set is too coarse, making it impossible to set the transmission power value so that the estimated received power value at the access point is within the allowable power range from the target received power value, the terminal's transmission is prohibited. In other words, if the estimated received power at the access point is between the lower and upper limits of the permissible power range, and there is no transmit power value that the terminal can set, then the terminal's transmission is prohibited. Furthermore, the method for setting the permissible power range will be described later.

[0368] Thus, when the maximum and minimum transmit power of the terminal, as well as the variable range of transmit power, limit the received power at the access point to the upper and lower limits of the allowable power range, and there is no transmit power value that the terminal can set, transmission is prohibited. This prevents the received power difference at the access point from increasing and reduces MU interference.

[0369] <Method 2 for setting allowable conditions>

[0370] Figure 26BThis is an example of the allowable condition setting method in allowable condition setting method 2. In allowable condition setting method 2, when the terminal cannot send a response signal at the transmission power value calculated using equation (3) due to limitations on the terminal's maximum transmission power, minimum transmission power, and variable transmission power range, the terminal estimates the received power value at the access point if it sends a response signal at the actual transmittable transmission power value. Moreover, even if the terminal sets its transmission power value to the minimum transmission power value, if the estimated received power value at the access point exceeds the upper limit of the allowable power range set based on the target received power value, the terminal's transmission is prohibited. Furthermore, if the spacing of the terminal's settable transmission power values ​​is too coarse, and it is impossible to set the estimated received power value at the access point to a transmission power value below the upper limit of the allowable power range, the terminal's transmission is prohibited. In other words, if the estimated received power value at the access point is below the upper limit of the allowable power range, and there is no settable transmission power value for the terminal, the terminal's transmission is prohibited.

[0371] In this way, by limiting the terminal's maximum transmit power, minimum transmit power, and variable transmit power range, transmission can be prohibited only when the estimated received power at the access point is below the upper limit of the permissible power range and there is no transmit power value that the terminal can set. This prevents the transmission of response signals that significantly interfere with the received signals of other terminals. In other words, by prohibiting the transmission of response signals with estimated received power values ​​that exceed the target received power value at the access point to a certain extent, MU interference can be reduced. Furthermore, by allowing transmission below the permissible lower power limit, the terminal's transmission opportunities can be prevented from decreasing.

[0372] <Method 3 for setting allowable conditions>

[0373] Figure 26C This is an example of the permission setting method in permission setting method 3. In permission setting method 3, when the terminal cannot send a response signal using the transmission power value calculated by equation (3), the terminal estimates the received power value at the access point if the response signal is sent with the actual transmittable transmission power value. Then, even if the terminal sets the transmission power value to the minimum transmission power value, if the estimated received power value at the access point exceeds the target received power value, the terminal's transmission is prohibited. Furthermore, if the interval between the transmit power values ​​that the terminal can set is too coarse, and the estimated received power value at the access point cannot be set to a transmission power value below the target received power value, the terminal's transmission is prohibited. In other words, the terminal's transmission is prohibited only if the estimated received power value at the access point exceeds the target received power value notified by the access point.

[0374] In this way, transmission is prohibited only when the estimated received power at the access point exceeds the target received power value notified by the access point due to limitations on the terminal's maximum transmit power, minimum transmit power, and transmit power variable amplitude. Therefore, the transmission of the response signal can be restricted under stricter conditions than in method 2 of setting permissible conditions, further reducing MU interference. Furthermore, by allowing transmissions below the target received power value, the reduction in the terminal's transmission opportunities can be further prevented.

[0375] The above describes methods 1 to 3 for setting the permissible conditions in this embodiment.

[0376] The following uses Figures 27A to 27D Methods 1 to 4 for setting the range of allowable power values ​​in methods 1 to 3 for setting allowable conditions are explained respectively.

[0377] <Method 1 for setting the range of allowable power values>

[0378] Figure 27A This is an example of a method for setting the range of allowable power values ​​in Method 1. In Method 1, the range of allowable power values ​​is changed according to the performance of the terminal (e.g., Class A, Class B). For example, the range of allowable power values ​​is increased for Class A terminals, while the range of allowable power values ​​is decreased for Class B terminals compared to Class A terminals. This is because the setting accuracy of the transmission power of Class A terminals is higher than that of Class B terminals.

[0379] Thus, in terminals with lower performance, the difference between the actual received power value and the target received power value at the access point is more likely to increase due to the lower accuracy of received power estimation. Therefore, by adjusting the range of the allowable power value according to the terminal's performance, it is easy to prohibit the transmission of terminals with lower performance and reduce MU interference.

[0380] <Method 2 for setting the range of allowable power values>

[0381] Figure 27B This is an example of a method for setting the range of allowable power values ​​in Method 2. In Method 2, the range of allowable power values ​​is changed based on random access allocation or individual allocation. For example, the range of allowable power values ​​is increased in individual allocation and decreased in random access allocation.

[0382] In random access allocation, the access point side has difficulty determining which terminal secures resources through random access, so the scheduler cannot allocate resources considering the difference in received power. Therefore, random access allocation is more prone to increasing interference from adjacent RUs caused by the difference in received power compared to individual allocation. Thus, there is a tendency for interference caused by the difference in received power to easily occur. Therefore, according to this setting method 2, MU interference can be reduced by easily disabling the transmission of terminals in random access allocation.

[0383] <Method 3 for setting the range of allowable power values>

[0384] Figure 27C This is an example of a method for setting the range of allowable power values ​​in Method 3. In Method 3, the range of allowable power values ​​is changed based on the number of terminals connected to the access point and information about traffic volume (BSS LOAD). For example, when the BSS LOAD is low, i.e., when the number of terminals connected to the access point is small, the range of allowable power values ​​is increased. Conversely, when the BSS LOAD is high, i.e., when the number of terminals connected to the access point is large, the range of allowable power values ​​is decreased. Furthermore, the BSS LOAD is communicated via beacons.

[0385] When BSS LOAD is high, resource utilization is considered high, so the likelihood of adjacent RUs being used and signal collisions during random access are higher. Therefore, according to this setting method 3, MU interference can be reduced by easily disabling the transmission of terminals with high BSS LOAD.

[0386] <Method 4 for setting the range of allowable power values>

[0387] Figure 27D This is an example of a method for setting the range of allowable power values ​​in method 4. In method 4, the range of allowable power values ​​is changed based on the portion of the received power estimate at the access point that exceeds or falls below the target received power value, calculated using equation (3). For example, the range of allowable power values ​​is decreased in the portion exceeding the target received power value, and increased in the portion falling below the target received power value.

[0388] When the target receive power value is exceeded, there is a tendency for increased interference to other terminals. Therefore, according to this setting method 4, MU interference can be reduced by easily prohibiting the transmission of response signals by terminals that can only transmit at a transmit power value exceeding the target receive power value.

[0389] The above describes methods 1 to 4 for setting the range of allowable power values ​​in this embodiment.

[0390] Furthermore, the range of permissible power values ​​can be the power difference from the target received power value, or it can be a range defined by the upper and lower limits of the permissible power value range. Additionally, in method 2 for setting the permissible conditions described above, only the upper limit of the permissible power value can be set.

[0391] Furthermore, the range of permissible power values ​​can use either predefined values ​​or values ​​notified by the access point.

[0392] Furthermore, the methods for setting the range of each permissible power value can also be combined.

[0393] Furthermore, the method for setting the permissible conditions and the method for setting the range of permissible power values ​​can also be dynamically changed according to the signaling from the access point.

[0394] Thus, in this embodiment, if the terminal 300's transmission power control capability (performance), such as limitations on the maximum transmission power, minimum transmission power, and variable transmission power range, prevents the terminal 300 from transmitting a UL response signal at a transmission power level that meets the allowable conditions based on the target received power value notified by the access point 100, the transmission control unit 301 prohibits the terminal 300 from transmitting. Therefore, regardless of the terminal 300's performance, i.e., limitations on its maximum transmission power, minimum transmission power, and variable transmission power range, the received power difference between terminals 300 in the access point 100 can be reduced. Therefore, according to this embodiment, MU interference can be reduced and system throughput improved.

[0395] The above describes various embodiments of the present invention.

[0396] [Other Implementation Methods]

[0397] (1) In the above embodiments, the random access control signal is a structure that always transmits the target received power value. However, it is also possible to have a structure that does not perform transmission power control, i.e., does not transmit the target received power value, based on the A / D conversion performance of the access point. It is also possible to switch whether to transmit the target received power value according to the trigger type.

[0398] (2) Furthermore, in the above embodiments, an example was given of a case in which the present invention is constituted by hardware, but the present invention can be implemented in software in conjunction with hardware.

[0399] Furthermore, while the above embodiments describe the use of a random access control signal that includes random access allocation, the method is not limited to this and can also be applied to cases that only include individual allocation. In particular, this is useful when the access point cannot properly evaluate path loss and the terminal's transmit power control capabilities due to reasons such as changes in the terminal's state and location.

[0400] Furthermore, in the communication method of the present invention, the transmit power (TRP) of the access point notified by the beacon, TF, TF-R, etc. can also be set to the power in the antenna connector that does not include the influence of antenna directivity, or, in the case of multiple antennas, to the sum of the powers in the multiple antenna connectors, i.e., the combined power.

[0401] Furthermore, the functional blocks described in the above embodiments are typically implemented as integrated circuits, i.e., LSIs. These integrated circuits control the functional blocks used in the above embodiments and may include input and output terminals. These integrated circuits can be integrated individually as a single chip, or they can contain some or all of the functional blocks integrated into a single chip. Here, although referred to as an LSI, depending on the degree of integration, they are sometimes also called ICs, system LSIs, Super LSIs, or Ultra LSIs.

[0402] Furthermore, the integrated circuit approach is not limited to LSIs; it can also be implemented using dedicated circuits or general-purpose processors. Alternatively, FPGAs (Field Programmable Gate Arrays) that are programmable after LSI fabrication can be used, or reconfigurable processors that connect and configure the internal circuitry of the reconfigurable LSI can be employed.

[0403] Furthermore, with advancements in semiconductor technology and the emergence of other derivative technologies, if an integrated circuit technology becomes available to replace LSI, it can certainly be used for the integration of functional blocks. There are also possibilities for its application in biotechnology and other fields.

[0404] The communication device of the present invention has the following structure: a target receive power setting unit that sets at least one target receive power value as UL transmit power control information for controlling the uplink transmit power of multiple terminals, wherein the target receive power value is a target value of the receive power when the multiple terminals receive uplink signals; a signal generation unit that generates a random access control signal containing at least one target receive power value; and a transmission unit that transmits the random access control signal.

[0405] In the communication device of the present invention, the random access control signal has: a common area for notifying common control information in multiple terminals; and a terminal-specific area for notifying individual control information of each of the multiple terminals. The signal generation unit configures the target received power value in the terminal-specific area of ​​the random access control signal.

[0406] In the communication device of the present invention, the random access control signal has: a common area for notifying common control information among multiple terminals; and a terminal-specific area for notifying individual control information of each of the multiple terminals. The signal generation unit configures the target received power value in the common area of ​​the random access control signal.

[0407] In the communication device of the present invention, the target reception power value is set to a different value for each category of information sent in random access.

[0408] In the communication device of the present invention, a target receive power value is assigned and randomly accessed for each individually allocated target.

[0409] In the communication device of the present invention, the signal generation unit configures the target received power value in the common area of ​​the random access control signal, and configures the offset value offset from the target received power value in the terminal-specific area of ​​the random access control signal.

[0410] In the communication device of the present invention, the signal generation unit configures the target receive power value in a separate area of ​​the terminal for a random access allocation terminal, and configures the transmit power value for transmitting uplink signals in a separate area of ​​the terminal for a separately allocated terminal.

[0411] In the communication device of the present invention, the signal generation unit configures the target received power value in a common area for randomly accessed and allocated terminals, and configures the target received power value in a terminal-specific area for individually allocated terminals.

[0412] The communication device of the present invention further includes: a transmission control unit that controls the target received power value contained in the random access control signal during continuous random access control signals.

[0413] In the communication device of the present invention, the target receive power setting unit sets a first target receive power value and a second target receive power value, and the transmission control unit performs a UL MU-MIMO / OFDMA transmission process with a random access control signal specifying the first target receive power value immediately after the UL MU-MIMO / OFDMA transmission process with a random access control signal specifying the second target receive power value.

[0414] In the communication device of the present invention, the transmission control unit sets the second target received power value to a value smaller than the first target received power value.

[0415] The communication method of the present invention includes: setting at least one target receive power value as UL transmit power control information for controlling the uplink transmit power of multiple terminals, wherein the target receive power value is a target value of the receive power when the multiple terminals receive uplink signals, generating a random access control signal containing at least one target receive power value, and transmitting the random access control signal.

[0416] In the communication method of the present invention, the random access control signal has: a common area for notifying common control information in multiple terminals; and a terminal-specific area for notifying individual control information of each of the multiple terminals, wherein the target received power value is configured in the terminal-specific area of ​​the random access control signal.

[0417] In the communication method of the present invention, the random access control signal has: a common area for notifying common control information in multiple terminals; and a terminal-specific area for notifying individual control information of each of the multiple terminals, wherein the target received power value is configured in the common area of ​​the random access control signal.

[0418] In the communication method of the present invention, the target received power value is set to a different value for each category of information sent in random access.

[0419] In the communication method of the present invention, a target receive power value is notified for each individually allocated, randomly accessed allocation.

[0420] In the communication method of the present invention, the target received power value is configured in the common area of ​​the random access control signal, and the offset value offset from the target received power value is configured in the terminal separate area of ​​the random access control signal.

[0421] In the communication method of the present invention, the target receive power value for the random access allocation terminal is configured in a separate area of ​​the terminal, and the transmit power value for transmitting the uplink signal of the separate allocation terminal is configured in a separate area of ​​the terminal.

[0422] In the communication method of the present invention, the target received power value for randomly accessed and allocated terminals is configured in a common area, and the target received power value for individually allocated terminals is configured in a terminal-specific area.

[0423] In the communication method of the present invention, when transmitting continuous random access control signals, the target received power value contained in the random access control signals is controlled.

[0424] In the communication method of the present invention, a first target receive power value and a second target receive power value are set, and a UL MU-MIMO / OFDMA transmission process with a random access control signal specifying the first target receive power value is performed immediately after the UL MU-MIMO / OFDMA transmission process with a random access control signal specifying the second target receive power value.

[0425] In the communication method of the present invention, the second target received power value is set to a value smaller than the first target received power value.

[0426] One aspect of the present invention, in UL MU-MIMO / OFDMA, is useful in improving inter-carrier interference and the dynamic range of AD conversion by reducing the difference in received power between terminals.

Claims

1. Terminal, equipped with: The receiving unit receives a trigger frame containing individual information, the individual information including a target receive power value related to the target value of the receive power when the access point receives the uplink response frame, i.e., the UL response frame. The control unit estimates the path loss by using the transmit power of the trigger frame notified by the trigger frame and the measured receive power of the trigger frame, and sets the transmit power of the UL response frame based on the target receive power value and the path loss; and The sending unit sends the UL response frame immediately after receiving the trigger frame. The trigger frame includes: The system includes a common area containing shared information for multiple terminals receiving the trigger frame and a separate area containing individual information for each of the multiple terminals. The individual information includes the modulation and coding scheme, i.e., MCS. The individual region contains multiple pieces of individual information for each of the plurality of terminals. The first piece of information included in the plurality of individual pieces of information contains a terminal identification ID for identifying the terminal corresponding to the first piece of information. The trigger frame is a random access control signal. The UL response frame is a random access response. The first separate piece of information includes resource unit allocation information for random access. Set a random access ID in the terminal identification ID.

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