First communication device, communication method, and integrated circuit

Abstract

To provide first wireless communication device capable of reducing interference with BSS that performs SR transmission via non-SR transmission.SOLUTION: The first wireless communication device includes: a control circuit that determines the transmission resource used for SR (spatial reuse) operation based on a piece of wireless quality information transmitted from a second wireless communication device; and a transmitting circuit that transmits an SR signal using the transmission resource.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a wireless communication device and a wireless communication method.

Background Art

[0002] In Task Group ax of the IEEE (the Institute of Electrical and Electronics Engineers) 802.11 Working Group, the technical specification of IEEE 802.11ax (hereinafter referred to as "11ax") is being developed as the next-generation standard of 802.11ac.

[0003] In the IEEE 802.11 standard, a BSS (Basic Service Set) is defined as a set of terminals (sometimes called "Station (STA)") that constitute a basic wireless network. The BSS is composed of one access point (sometimes called "Access point (AP)", "base station") and a plurality of terminals in the infrastructure mode, and is composed of a plurality of terminals in the ad-hoc mode.

[0004] A BSS other than the BSS (intra-BSS) to which the own terminal belongs is called an "OBSS (Overlapping BSS, or inter-BSS)". In an environment where a plurality of BSSs exist adjacent to each other, the radio wave interference from the surrounding OBSSs increases, and the system performance deteriorates due to the decrease in the transmission opportunity.

[0005] On the other hand, in 11ax, for the purpose of improving the system performance in an environment where BSSs exist at a high density, the introduction of SR (Spatial reuse) that obtains a transmission opportunity by reusing the radio resources used by the OBSS is defined (for example, see Non-Patent Document 1).

[0006] Non-Patent Document 1 defines two types of SR, namely, "OBSS PD (Packet detect)-based SR" and "SRP based SR". In OBSS PD-based SR, the STA obtains a transmission opportunity by dynamically controlling the CCA (Clear channel assessment) threshold based on the received power of the signal received from the OBSS (hereinafter referred to as the OBSS signal) and the BSS identifier (BSS color) of the OBSS. In SRP based SR, the STA derives the transmission power that satisfies the condition of not exceeding the interference tolerance value of the OBSS based on the interference tolerance value obtained from the OBSS signal ("Spatial reuse parameter (SRP)") and the received signal strength of the OBSS signal ("Received signal strength indication (RSSI)"). The STA transmits the signal with the derived transmission power to obtain a transmission opportunity while reducing the interference to the OBSS (see, for example, Non-Patent Document 2).

[0007] In the following description, the transmission applying the above SR is referred to as "SR transmission", and the transmission not applying the SR is referred to as "non-SR transmission". Also, in the following description, the signal transmitted by SR is referred to as "SR signal", and the signal not transmitted by SR is referred to as "non-SR signal".

Prior Art Documents

Non-Patent Documents

[0008]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0009] However, while the reduction of interference to OBSS by SR transmission is considered, the reduction of interference to a BSS that performs SR transmission by non - SR transmission has not been sufficiently studied.

[0010] One aspect of the present disclosure contributes to providing a wireless communication device and a wireless communication method capable of reducing interference to a BSS that performs SR transmission by non - SR transmission.

Means for Solving the Problems

[0011] A wireless communication device according to one aspect of the present disclosure includes a control circuit that determines a transmission resource of an SR (Spatial Reuse) signal transmitted by SR to a second BSS other than the first BSS based on wireless quality information transmitted from other wireless communication devices within a first BSS (Basic Service Set), and a transmission circuit that transmits the SR signal using the transmission resource.

[0012] A communication method according to one aspect of the present disclosure determines a transmission resource of an SR (Spatial Reuse) signal transmitted by SR to a second BSS other than the first BSS based on wireless quality information transmitted from other wireless communication devices within a first BSS (Basic Service Set), and transmits the SR signal using the transmission resource.

[0013] These general or specific aspects may be implemented in a system, device, method, integrated circuit, computer program, or recording medium, or may be implemented in any combination of a system, device, method, integrated circuit, computer program, and recording medium.

Advantages of the Invention

[0014] According to one aspect of the present disclosure, interference to a BSS that performs SR transmission by non-SR transmission can be reduced.

[0015] Further advantages and effects in one aspect of the present disclosure will be clarified from the specification and the drawings. Such advantages and / or effects are provided by some embodiments and the features described in the specification and the drawings respectively, but not all of them are necessarily provided in order to obtain one or more identical features.

Brief Description of the Drawings

[0016]

Figure 1

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Embodiments for Carrying Out the Invention

[0017] Hereinafter, each embodiment of the present disclosure will be described in detail with reference to the drawings.

[0018] [SRP based SR] SRP based SR will be described in detail with reference to FIG. 1.

[0019] An AP (OBSS AP) belonging to an OBSS existing around its own BSS transmits a trigger frame, which is a control signal that prompts the transmission of an uplink signal (for example, an OFDMA (Orthogonal Frequency Division Multiple Access) signal), to an STA (OBSS STA) within the OBSS to which it belongs. Here, a data frame including the trigger frame is called a "DSRP PPDU (Delayed SRP Physical layer Protocol Data Unit)". The SR initiator of its own BSS receives the DSRP PPDU transmitted from the OBSS AP to the OBSS STA (see the left side of FIG. 1).

[0020] Note that the "SR initiator" is a device (AP or STA) that attempts SR transmission when the SRP obtained from the received OBSS signal takes a predetermined value. Also, the device (AP or STA) that is the communication partner of the SR initiator in SR transmission is called the "SR responder".

[0021] The SR initiator derives the transmission power that reduces interference to the OBSS in order to reuse the radio resources used by the OBSS.

[0022] Specifically, the SR initiator obtains the SRP of the OBSS AP defined by the BSS color included in the SIG-A-field of the received DSRP PPDU and the value of the Spatial reuse subfield within the Common field of the Trigger frame (see, for example, Non-Patent Document 3). The SRP is represented by the following equation (1). SRP = TXPWR AP + Acceptable receiver interference level AP …(1)

[0023] In equation (1), TXPWR AP indicates the transmission power of the OBSS AP, and Acceptable receiver interference level AP indicates the allowable interference level of the OBSS AP.

[0024] Also, the SR initiator measures the RSSI (RSSI Trigger frame ) of the received DSRP PPDU.

[0025] Then, the SR initiator derives the transmission power (TXPWR SR initiator ) of the SR signal from the following equation (2) using the SRP and RSSI. TXPWR SR initiator < SRP - RSSI trigger frame …(2)

[0026] The SR initiator transmits an SR signal to the SR responder using the derived transmission power. By using the transmission power derived from Equation (2), interference to OBSS caused by SR transmission from the SR initiator to the SR responder can be reduced (see the right side of FIG. 1).

[0027] In SRP-based SR, the SR initiator reuses radio resources and improves system performance by transmitting an SR signal to an SR responder belonging to the same BSS as the SR initiator with the derived transmission power during the period (SRP opportunity) when the uplink signal of the OBSS STA detected from the Trigger frame is being transmitted.

[0028] Here, when the SR initiator performs SR transmission to the SR responder with transmission power that reduces interference to OBSS, the SR signal is transmitted at a lower power than the normal transmission power. Therefore, it is desirable that the interference at the SR responder is small.

[0029] However, as shown in FIG. 2, when the SR responder is close to an OBSS (STA1 in FIG. 2), non-SR transmission in the OBSS (STA1) becomes a large interference to the SR responder, and the reception success rate of the SR signal at the SR responder may decrease. In addition, an SR signal that fails to be received at the SR responder can be an interference source to an OBSS that is closer to the SR initiator than the OBSS (OBSS including the AP in FIG. 2) that is the target of interference reduction and is not the target of interference reduction (OBSS including STA2 in FIG. 2).

[0030] Thus, depending on the radio channel condition of the SR responder, interference from the OBSS may be received during SR transmission, the reception success rate of the SR signal at the SR responder may decrease, and the system performance may deteriorate.

[0031] Therefore, in one aspect of the present disclosure, a method for reducing interference received from an OBSS in SR transmission will be described.

[0032] (Embodiment 1) [Configuration of Wireless Communication System] In the wireless communication system according to the present embodiment, a plurality of BSSs exist adjacent to each other. In the wireless communication system, a device (STA or AP) constituting at least one BSS performs SRP-based SR (that is, reuse of wireless resources used by an OBSS) on a surrounding OBSS.

[0033] Hereinafter, as an example, a SR initiator (wireless communication device) 100 and a SR responder (wireless communication device) 200 that perform SRP-based SR are provided. That is, the wireless communication device 100 transmits a SR signal to the wireless communication device 200. For example, the SR initiator is a STA, and the SR responder is an AP.

[0034] FIG. 3 is a block diagram showing a partial configuration of the wireless communication device 100 (SR initiator) according to the present embodiment. In the wireless communication device 100 shown in FIG. 3, a SR transmission resource control unit 107 determines a transmission resource of a SR signal transmitted by SR (for example, SRP-based SR) with respect to a second BSS (that is, an OBSS) other than the first BSS based on wireless quality information transmitted from another wireless communication device (SR responder) in the first BSS. The wireless transmission / reception unit 101 transmits a SR signal using the transmission resource.

[0035] [Configuration of SR initiator] FIG. 4 is a block diagram showing a configuration example of the wireless communication device 100 (SR initiator) according to the present embodiment. The wireless communication device 100 determines a transmission resource for a SR signal based on wireless quality information from the wireless communication device 200 that is a SR responder, and transmits the SR signal within a predetermined period.

[0036] The wireless communication device 100 includes a wireless transceiver 101, a received power measurement unit 102, a demodulation unit 103, a decoding unit 104, an SR transmission power reduction unit 105, a wireless quality information holding unit 106, an SR transmission resource control unit 107, an encoding unit 108, a Preamble generation unit 109, and a modulation unit 110. The SR transmission power reduction unit 105 and the SR transmission resource control unit 107 constitute an SR control unit.

[0037] The wireless transceiver 101 receives a wireless signal (OBSS signal) transmitted from an OBSS (for example, an OBSS AP or an OBSS STA) via an antenna, performs predetermined wireless reception processing such as down-conversion and A / D conversion on the wireless signal, and outputs the received signal after the wireless reception processing to the received power measurement unit 102 and the demodulation unit 103.

[0038] Also, the wireless transceiver 101 performs predetermined wireless transmission processing such as D / A conversion and up-conversion to a carrier frequency on the packet signal input from the modulation unit 110, and amplifies the high-frequency signal (that is, the SR signal) according to the transmission power indicated by the transmission power information (described later) input from the SR transmission resource control unit 107, and transmits the amplified high-frequency signal via an antenna.

[0039] The received power measurement unit 102 measures the received power (for example, RSSI) using the received signal (that is, the OBSS signal) input from the wireless transceiver 101, and outputs the measured RSSI to the SR transmission power reduction unit 105.

[0040] The demodulation unit 103 detects the Preamble included in the received signal input from the wireless transceiver 101, extracts the received data including the Trigger frame based on the control information included in the Preamble, and demodulates the received data. The demodulation unit 103 outputs the control information and the received data after demodulation to the decoding unit 104.

[0041] The decoding unit 104 decodes the received data and obtains the Trigger frame based on the control information included in the Preamble input from the demodulation unit 103. Then, the decoding unit 104 outputs the decoded Trigger frame and the control information included in the Preamble to the SR transmission power reduction unit 105 and the SR transmission resource control unit 107.

[0042] The SR transmission power reduction unit 105 determines whether SR transmission is permitted based on the control information included in the Trigger frame input from the decoding unit 104. For example, when the value of the Spatial reuse subfield included in the Common field of the Trigger frame is other than "SRP_DISALLOW" and "SRP_AND_NON - SRG_OBSS - PD_PROHIBITED", the SR transmission power reduction unit 105 determines that SR transmission is permitted. That is, when the value of the Spatial reuse subfield is "SRP_DISALLOW" or "SRP_AND_NON - SRG_OBSS - PD_PROHIBITED", the SR transmission power reduction unit 105 determines that SR transmission is not permitted (non - permitted).

[0043] When the SR transmission power reduction unit 105 determines that SR transmission is permitted, it reduces the transmission power in SR transmission. Specifically, the SR transmission power reduction unit 105 uses the SRP [dBm] included in the Trigger frame and the RSSI (RSSI trigger frame ) of the Trigger frame input from the received power measurement unit 102 to determine the transmission power (TXPWR SR initiator ) that satisfies Equation (2). The SR transmission power reduction unit 105 outputs information indicating the determined transmission power to the SR transmission resource control unit 107.

[0044] On the other hand, when it is determined that SR transmission is not permitted, the SR transmission power reduction unit 105 outputs nothing (output OFF) to the SR transmission resource control unit 107, or outputs information instructing non-SR transmission to the SR transmission resource control unit 107, thereby aborting SR transmission. Also, the SR transmission power reduction unit 105 may abort SR transmission even when it cannot reduce the transmission power to satisfy formula (2) due to, for example, implementation constraints.

[0045] The radio quality information holding unit 106 holds the radio quality information received from the wireless communication device 200 (SR responder). For example, the radio quality information may be notified from the wireless communication device 200 at a predetermined period or at a predetermined timing via a management frame or a control frame. Also, the radio quality information may be information indicating the radio quality for each predetermined band. The radio quality information holding unit 106 outputs, for example, the most recently received radio quality information to the SR transmission resource control unit 107. Details of the radio quality information will be described later.

[0046] The SR transmission resource control unit 107 determines the SR transmission resources (e.g., time resources, frequency resources, transmission power resources) of the SR signal transmitted in SR transmission for OBSS. For example, the SR transmission resource control unit 107 sets the time resource of the SR signal (also called SRP opportunity) to a time shorter than that of the Trigger-based PPDU (non-SR signal) based on the information regarding the packet length of the Trigger-based PPDU obtained from the Trigger frame. Also, the SR transmission resource control unit 107 determines the availability of SR transmission for each band based on the radio quality information for each predetermined band input from the radio quality information holding unit 106 with respect to the frequency resources. Note that the SR transmission resource control unit 107 may abort SR transmission when there is no band available for SR transmission. Also, the SR transmission resource control unit 107 sets the transmission power resource to the transmission power indicated by the information input from the SR transmission power reduction unit 105.

[0047] Then, the SR transmission resource control unit 107 outputs information indicating the determined SR transmission resources (time resource information, transmission bandwidth information, transmission power information) to the encoding unit 108, the Preamble generation unit 109, and the wireless transceiver unit 101, respectively.

[0048] Details of the method for determining the frequency resources of the SR signal in the SR transmission resource control unit 107 will be described later.

[0049] The encoding unit 108 determines the length of the PSDU (PHY Service Data Unit) that can be transmitted within the section indicated by the time resource information input from the SR transmission resource control unit 107, and uses the MCS (Modulation and Coding Scheme) obtained from the reception quality estimation value (such as wireless quality information) in the wireless communication device 200 (SR responder) to encode the SR signal (including data, etc.), and outputs the encoded signal to the modulation unit 110.

[0050] The Preamble generation unit 109 generates a Preamble including control information including the bandwidth allocation information of the SR signal (also called RU allocation information) and a reference signal based on the transmission bandwidth information input from the SR transmission resource control unit 107, and outputs the generated Preamble to the modulation unit 110. Details of the method for generating the bandwidth allocation information of the SR signal will be described later.

[0051] The modulation unit 110 performs modulation (for example, QAM (Quadrature Amplitude Modulation)) on the signal input from the encoding unit 108. Then, the modulation unit 110 assigns the modulated signal to the band indicated by the band allocation information of the SR signal included in the Preamble (the SR transmittable band), and generates an OFDM (Orthogonal Frequency Division Multiplexing) signal by performing IFFT (Inverse Fast Fourier Transform) processing, thereby generating a data signal composed of the OFDM signal. Then, the modulation unit 110 generates a radio frame (packet signal) with the Preamble added to the data signal, and outputs the packet signal to the radio transceiver unit 101.

[0052] [Configuration of SR responder] FIG. 5 is a block diagram showing the configuration of the wireless communication device 200 (SR responder) according to the present embodiment. The wireless communication device 200 transmits wireless quality information for each predetermined band (for example, information such as interference level, SINR (Signal to Interference and Noise Ratio), etc.) to the wireless communication device 100 which is an SR initiator, and receives an SR signal from the wireless communication device 100.

[0053] The wireless communication device 200 includes a wireless transceiver unit 201, a demodulation unit 202, a decoding unit 203, a wireless quality measurement unit 204, a wireless quality information generation unit 205, and a modulation unit 206.

[0054] The wireless transceiver unit 201 receives a signal from a BSS (for example, an SR initiator) or an OBSS (for example, an OBSS AP or an OBSS STA) via an antenna, performs predetermined wireless reception processing such as down-conversion and A / D conversion on the received signal, and outputs the received signal after the wireless reception processing to the demodulation unit 202 or the wireless quality measurement unit 204.

[0055] In addition, the wireless transceiver unit 201 performs predetermined wireless transmission processing such as D / A conversion and up-conversion to the carrier frequency on the signal (including wireless quality information) input from the modulation unit 206, and notifies the wireless quality information to the STAs (including the wireless communication device 100) within the BSS to which it belongs via the antenna.

[0056] The demodulation unit 202 detects the Preamble from the received signal input from the wireless transceiver unit 201, and acquires the frequency allocation information from the band allocation information included in the Preamble. Then, the demodulation unit 202 extracts the wireless frame including the desired data (corresponding to the SR signal) based on the frequency allocation information, and outputs it to the decoding unit 203.

[0057] The decoding unit 203 decodes the received data (SR signal) based on the control information included in the received signal input from the demodulation unit 202, and acquires the data included in the SR signal.

[0058] The wireless quality measurement unit 204 measures the wireless quality (received power or interference level) using the received signal (for example, an OBSS signal or a signal of the BSS to which it belongs) input from the wireless transceiver unit 201, and outputs the measurement result to the wireless quality information generation unit 205. Details of the wireless quality measurement in the wireless quality measurement unit 204 will be described later.

[0059] The wireless quality information generation unit 205 generates wireless quality information including the measurement result input from the wireless quality measurement unit 204, and outputs the wireless quality information to the modulation unit 206.

[0060] For example, the radio quality information generation unit 205 generates a management frame or a control frame addressed to the SR initiator (wireless communication device 100) that includes the measurement results input from the radio quality measurement unit 204. For example, when the SR responder is an AP, the radio quality information generation unit 205 may use a beacon frame, which is a management frame, or a Trigger frame, which is a control frame. Also, when the SR responder is a STA, the radio quality information generation unit 205 may use a BQR (Bandwidth Query Report) as a response to a Trigger frame with a Trigger type of BQRP (Bandwidth Query Report Poll) transmitted by the AP (wireless communication device 100), which is the SR initiator.

[0061] The modulation unit 206 allocates a signal obtained by modulating the radio quality information input from the radio quality information generation unit 205 to a predetermined band and outputs it to the radio transceiver unit 201.

[0062] [Operations of Wireless Communication Device 100 and Wireless Communication Device 200] Next, the operations of the wireless communication device 100 and the wireless communication device 200 according to the present embodiment will be described in detail.

[0063] In the present embodiment, the SR initiator (wireless communication device 100) determines an SR transmission resource (including a transmission band and transmission power) for the SR signal based on the radio quality information from the SR responder (wireless communication device 200).

[0064] FIG. 6 is a sequence diagram showing an example of the operation of the wireless communication system according to the present embodiment. FIG. 6 shows, as an example, the operation when an SR initiator and an SR responder belonging to a predetermined BSS apply SRP-based SR to an OBSS (including an OBSS AP and an OBSS STA) adjacent to the BSS.

[0065] In FIG. 6, the SR responder (radio quality measurement unit 204) measures the received power or interference level for each predetermined band using signals from a predetermined BSS or OBSS, and generates radio quality information based on the measurement results (ST101). Then, the SR responder notifies the STA (including the SR initiator) within the BSS of the signal including the generated radio quality information (ST102).

[0066] Note that in ST102, the radio quality information may be notified at a predetermined timing or a predetermined period defined in advance. For example, the SR responder may measure the radio quality at a predetermined period in ST101 and notify the radio quality information each time the radio quality is measured, or may be notified at other timings other than the above.

[0067] The OBSS AP generates a Trigger frame that prompts the OBSS STA to perform an uplink transmission, and transmits the Trigger frame to the OBSS STA (ST103). The Trigger frame transmitted from the OBSS AP to the OBSS STA is also received by the SR initiator.

[0068] The SR initiator (SR transmission power reduction unit 105) determines the transmission power of the SR signal (hereinafter, also referred to as the SR transmission power) for reducing the interference to the OBSS AP using the interference tolerance value (SRP) of the OBSS AP obtained from the Trigger frame received from the OBSS AP in ST103 and the RSSI measured using the Trigger frame (ST104).

[0069] The SR initiator (SR transmission resource control unit 107) determines the SR transmission period (SRP opportunity, i.e., time resource) based on the packet length information of the non-SR signal transmitted by the OBSS STA, which is obtained from the Trigger frame received from the OBSS AP in ST103 (ST105). Also, the SR initiator (SR transmission resource control unit 107) determines the transmission resource (frequency resource) of the SR signal for which the desired reception quality can be expected based on the radio quality information for each predetermined band received from the SR responder in ST102 (ST105).

[0070] Note that in ST105, the SR initiator determines the transmission resource of the SR signal when transmitting the SR signal during the transmission period of the non-SR signal (also called SRP opportunity) obtained based on, for example, the Trigger frame received in ST103. When not transmitting the SR signal during the transmission period of the non-SR signal (for example, when transmission is not possible), the SR initiator may not determine the transmission resource of the SR signal. Thereby, the SR initiator only needs to perform transmission resource control for the SR signal only when the transmission of the SR signal is necessary, and the processing amount can be reduced.

[0071] On the other hand, the OBSS STA transmits an uplink signal (i.e., non-SR signal) to the OBSS AP based on the instruction by the Trigger frame received from the OBSS AP in ST103 (ST106).

[0072] The SR initiator transmits the SR signal to the SR responder using the SR transmission power determined in ST104 and the transmission resource determined in ST105 within the SR transmission period (SRP opportunity) determined in ST105 (ST107).

[0073] The SR responder receives the SR signal transmitted from the SR initiator in ST107 and decodes the received SR signal (ST108).

[0074] Also, the OBSS AP receives the non-SR signal transmitted from the OBSS STA at ST106 and decodes the received non-SR signal (ST109).

[0075] FIGS. 7 and 8 show operation examples of SRP-based SR (SR resource control using radio quality information) according to this embodiment.

[0076] In FIG. 7, the SR responder notifies the SR initiator of radio quality information indicating that interference from the OBSS is small. In this case, the SR initiator determines that SR transmission is possible based on the received radio quality information. Therefore, the SR initiator performs SR transmission using available transmission resources (i.e., transmission resources with little interference from the OBSS and where a desired reception quality can be expected).

[0077] That is, in FIG. 7, since the SR initiator transmits the SR signal using a resource with little interference from the non-SR signal of the OBSS STA, the occurrence of decoding errors of the SR signal at the SR responder can be reduced.

[0078] Also, in FIG. 7, the SR signal transmitted from the SR initiator can cause interference to the OBSS AP. However, since the transmission power is reduced by the transmission power control at the SR initiator (ST104 in FIG. 6) so that the interference power is below the allowable value, the occurrence of decoding errors of the non-SR signal at the OBSS AP can be reduced.

[0079] Also, in FIG. 7, an OBSS that is not the target of the co-channel interference reduction process of SR transmission (STA2 in FIG. 7) cannot transmit because it is interfered with by the SR transmission.

[0080] On the other hand, in FIG. 8, the SR responder notifies the SR initiator of radio quality information indicating that the interference from the OBSS is large. In this case, the SR initiator determines that SR transmission is impossible based on the received radio quality information. Therefore, the SR initiator aborts the SR transmission.

[0081] That is, in FIG. 8, the SR initiator does not perform SR transmission in a resource where the interference by the non-SR signal from the OBSS STA is large and the decoding error of the SR signal in the SR responder is likely to occur. As a result, in FIG. 8, since the SR signal is not transmitted, the occurrence of the decoding error of the non-SR signal in the OBSS AP can be reduced. Further, in FIG. 8, the OBSS (STA2 in FIG. 8) that is not the target of the interference reduction process for SR transmission becomes transmittable because the interference by the SR transmission disappears.

[0082] As shown in FIGS. 7 and 8, the SR initiator determines a transmission resource (band) where the SR signal can be transmitted in consideration of the interference by the non-SR signal transmitted from the OBSS (here, the OBSS STA) based on the radio quality information from the SR responder, transmits the SR signal in the transmission resource where transmission is possible, and does not transmit SR in resources other than the transmission resource where transmission is possible. Thereby, even when the non-SR signal can cause interference depending on the radio channel situation (such as the surrounding environment) of the SR responder, the SR signal is transmitted in a band with small interference, and the SR signal is not transmitted in a band that is easily interfered with, so that the occurrence of the decoding error of the SR signal in the SR responder can be reduced.

[0083] [SR Signal Frequency Resource Determination Method] Next, the method for determining the frequency resource of the SR signal in the SR transmission resource control unit 107 of the wireless communication device 100 (SR initiator) will be described in more detail.

[0084] The SR transmission resource control unit 107 determines the frequency resource of the SR signal based on the radio quality information received from the wireless communication device 200 (SR responder).

[0085] <Radio quality information> Here, the radio quality information is information indicating the radio quality generated by the SR responder for each predetermined band, and for example, indicates the following information. (1) The CCA result (Idle / Busy) indicating whether the SR responder can receive the SR signal (that is, whether the SR initiator can transmit the SR signal) (2) Information indicating whether the interference level measured by the SR responder is higher or lower than a predetermined threshold (3) The interference level measured by the SR responder (4) The reception quality information (e.g., SINR) from the SR initiator to the SR responder

[0086] For example, in the case of (2), when the SR transmission resource control unit 107 receives radio quality information indicating that the interference level is lower than a predetermined threshold, it may determine that the SR responder can receive the SR signal. Also, in the case of (3), the SR transmission resource control unit 107 determines whether the interference level is lower than a predetermined threshold, and if the interference level is lower than the threshold, it may determine that the SR responder can receive the SR signal. Also, in the case of (4), the SR transmission resource control unit 107 determines whether the SINR is higher than a predetermined threshold, and if the SINR is higher than the threshold, it may determine that the SR responder can receive the SR signal.

[0087] Also, the predetermined band defining the radio quality information may be, for example, as shown in FIG. 9, the band of the minimum allocation unit (RU (Resource Unit) unit) of OFDMA. FIG. 9 is, as an example, the radio quality information (SR availability information) for each RU indicating whether the SR initiator in (1) above can transmit the SR signal (transmittable or non-transmittable).

[0088] In the case of Fig. 9, the SR transmission resource control unit 107 allocates the frequency resources of the SR signal to the RUs (RUs with low interference levels) for which SR transmission is permitted. On the other hand, the SR transmission resource control unit 107 does not allocate the frequency resources of the SR signal to the RUs (RUs with high interference levels) for which SR transmission is not permitted.

[0089] Here, the non-SR signal from the OBSS STA indicated by the Trigger frame is a UL OFDMA signal, and is a signal in which signals from a plurality of STAs are multiplexed by frequency multiplexing in units of RUs. Therefore, in the non-SR signal, it is assumed that the interference level varies greatly in units of RUs depending on the OFDMA allocation by a plurality of STAs.

[0090] Therefore, by defining the radio quality information in units of RUs, the SR transmission resource control unit 107 can allocate the frequency resources of the SR signal in consideration of the increase and decrease of the interference level depending on the OFDMA allocation of the STA that transmits the non-SR signal, can prevent a decrease in the reception success rate of the SR signal at the SR responder, and can improve the system performance.

[0091] Alternatively, the predetermined band for defining the radio quality information may be, for example, a band in units of 20 MHz bands as shown in Fig. 10. Fig. 10 shows, as an example, the radio quality information (SR permission / non-permission information) for each channel in a 20 MHz band indicating whether or not the SR initiator in (1) above can transmit an SR signal (transmittable or non-transmittable).

[0092] In the case of Fig. 10, the SR transmission resource control unit 107 allocates the frequency resources of the SR signal to the bands for which SR transmission is permitted (20 MHz channels with low interference levels). On the other hand, the SR transmission resource control unit 107 does not allocate the frequency resources of the SR signal to the bands for which SR transmission is not permitted (20 MHz channels with high interference levels).

[0093] Here, the average interference level received by the SR responder depends on the arrangement of APs existing in the vicinity. Also, since the primary channel set by each AP is in units of 20 MHz, it is assumed that, regarding the interference received by the SR responder, the interference level varies significantly in units of 20 MHz depending on the arrangement of the surrounding APs.

[0094] Therefore, by defining radio quality information in units of 20 MHz, the SR transmission resource control unit 107 can allocate the frequency resources of the SR signal in consideration of the increase and decrease of the interference level depending on the surrounding AP environment of the SR responder, prevent the decrease in the reception success rate of the SR signal at the SR responder, and improve the system performance.

[0095] [Method for Generating Band Allocation Information of SR Signal] Next, the method for generating the band allocation information (RU allocation information) of the SR transmission signal in the Preamble generation unit 109 of the wireless communication device 100 (SR initiator) will be described in more detail.

[0096] Based on the transmission band information input from the SR transmission resource control unit 107, the Preamble generation unit 109 determines the band allocation information (RU allocation information) in consideration of the amount of signaling bits and the degree of allocation freedom.

[0097] For example, the Preamble generation unit 109 may generate the band allocation information by arranging a flag indicating the presence or absence of the allocated band of the SR signal in a bitmap for each predetermined band (for example, in units of RU or 20 MHz). Thereby, the frequency resources of the SR signal can be allocated freely (i.e., without restrictions) for each predetermined band. On the other hand, in the bitmap arrangement for each predetermined band, the amount of signaling bits increases.

[0098] Alternatively, the Preamble generation unit 109 may generate band allocation information by bitmap-arranging a flag indicating the presence or absence of the allocated band of the SR signal for each RU group (RUG) composed of a plurality of consecutive RUs. Thereby, compared with the bitmap arrangement in terms of RU units, the amount of signaling bits can be reduced. On the other hand, a constraint of RUG units is imposed on the frequency resource allocation of the SR signal, and the scheduling gain is reduced compared with the allocation in terms of RU units.

[0099] Also, the Preamble generation unit 109 may generate band allocation information by reusing the RU Allocation subfield included in the User Info field of the Trigger frame. Thereby, implementation becomes easy by applying the allocation rules of the existing system, and the amount of signaling bits can also be reduced. On the other hand, a constraint is imposed on the frequency resource allocation of the SR signal, and the scheduling gain is reduced.

[0100] The Preamble generation unit 109 may determine the generation method in consideration of the allowable amount of overhead (amount of signaling bits) assumed in the wireless communication system and the expected scheduling gain, and generate the band allocation information. Thereby, the system performance can be improved.

[0101] Note that the method for generating the band allocation information of the SR signal described above can be similarly applied to the radio quality information generation unit 205 of the SR responder. Specifically, the radio quality information generation unit 205 may notify radio quality information such as the magnitude of the measured interference level or the transmission availability (reception availability) of the SR signal as 1-bit information for each predetermined band (for example, RU or 20 MHz). In this case, the radio quality information generation unit 205 may determine the generation method of the radio quality information in consideration of the amount of signaling bits and the degree of freedom of notification of the radio quality information as described above. Thereby, the radio quality information generation unit 205 can generate appropriate radio quality information in consideration of the allowable amount of overhead assumed in the wireless communication system and the expected scheduling gain, and improve the system performance.

[0102] The above describes the method for generating the band allocation information.

[0103] [Effect] As described above, according to this embodiment, the wireless communication device 100 (SR initiator) determines the transmission resource (frequency resource) of the SR signal transmitted by SR to an OBSS other than the BSS to which it belongs based on the wireless quality information transmitted from another wireless communication device 200 (SR responder) within the BSS to which it belongs, and transmits the SR signal using the determined transmission resource.

[0104] Thereby, the SR initiator can determine the transmission resource (band) of the SR signal according to the wireless channel situation (for example, interference situation) in the SR responder and transmit the SR signal. Therefore, according to this embodiment, in the SR responder, interference to the BSS (SR responder) that performs SR transmission by non-SR transmission of the OBSS can be reduced, the reception success rate of the SR signal can be improved, and the system performance can be improved.

[0105] Also, in this embodiment, the SR initiator does not transmit the SR signal in the band where it is determined that the reception success rate of the SR signal in the SR responder is low. Thereby, in the band where the SR signal is not transmitted, it is possible to prevent the SR signal from becoming an interference source to an OBSS that is closer to the SR initiator than the OBSS that is the target of interference reduction and is not the target of interference reduction.

[0106] (Embodiment 2) In this embodiment, a method for the SR initiator to control SR transmission based on the BSS color will be described.

[0107] In the following description, a group of BSSs having a specific BSS color is referred to as an "SRG (Spatial Reuse Group)".

[0108] BSSs belonging to different SRGs are managed by different operators. Therefore, in this embodiment, when the SR initiator performs an SR transmission to an OBSS belonging to an SRG different from the BSS to which it belongs, the SR initiator controls the SR transmission so as not to interfere with the surrounding OBSSs other than the OBSS that is the target of the SR transmission.

[0109] Since the SR initiator and the SR responder according to this embodiment have the same basic configuration as the wireless communication device 100 and the wireless communication device 200 according to Embodiment 1, they will be described with reference to FIGS. 4 and 5.

[0110] [Configuration of SR initiator] The wireless communication device 100 (SR initiator) according to this embodiment receives a wireless frame including a Trigger frame transmitted from an OBSS, determines whether SR transmission is possible based on the BSS color or SRG of the obtained OBSS and the wireless quality information transmitted from the SR responder, and if SR transmission is possible, transmits an SR signal within a predetermined period.

[0111] The operation of the SR transmission resource control unit 107 of the wireless communication device 100 according to this embodiment is different from that of the wireless communication device 100 according to Embodiment 1.

[0112] Also, the wireless quality information held by the wireless quality information holding unit 106 is wireless quality information for each SRG or for each BSS color (BSS).

[0113] Specifically, the SR transmission resource control unit 107 acquires the BSS color corresponding to the OBSS (the OBSS to which the OBSS STA that transmits a non-SR signal belongs) that is a source of interference with the SR signal from the control information included in the Preamble input from the decoding unit 104.

[0114] Further, the SR transmission resource control unit 107 determines whether an OBSS (BSS color) that is a source of interference for the SR signal belongs to the same SRG as the BSS to which the own device (wireless communication device 100) belongs, based on the SRG information (e.g., SRG BSS Color Bitmap subfield) included in the beacon frame transmitted by the AP within the BSS to which the own device belongs. In the following description, a BSS having a BSS color belonging to the same group as the BSS color of the BSS (own BSS) to which the SR initiator and the SR responder belong is simply referred to as "SRG", and a BSS having a BSS color belonging to another group is referred to as "Non-SRG".

[0115] Then, the SR transmission resource control unit 107 determines whether SR transmission is possible based on the radio quality information for each SRG or for each BSS color input from the radio quality information holding unit 106. For example, the SR transmission resource control unit 107 determines whether SR transmission is possible based on the radio quality information of the group (SRG or Non-SRG) to which the OBSS that is a source of interference for the SR signal belongs, among the radio quality information for each SRG. Alternatively, the SR transmission resource control unit 107 determines whether SR transmission is possible based on the radio quality information of the BSS color corresponding to the OBSS that is a source of interference for the SR signal, among the radio quality information for each BSS color.

[0116] When the SR transmission resource control unit 107 determines that SR transmission is impossible, the SR transmission resource control unit 107 turns off the output from the SR transmission resource control unit 107, or outputs information instructing non-transmission of SR, thereby aborting SR transmission.

[0117] On the other hand, when the SR transmission resource control unit 107 determines that SR transmission is possible, it determines the time resource and transmission power resource of the SR signal in the same manner as in the first embodiment. That is, the SR transmission resource control unit 107 sets the transmission power input from the SR transmission power reduction unit 105 as the transmission power resource. Further, the SR transmission resource control unit 107 sets a time shorter than the packet length of the Trigger-based PPDU (non-SR signal) as the time resource. Further, the SR transmission resource control unit 107 sets a predetermined band corresponding to the transmission data size of the SR signal including, for example, the Primary channel as the frequency resource.

[0118] The SR transmission resource control unit 107 outputs the determined SR transmission resources to the encoding unit 108 and the wireless transmission / reception unit 101. Details of the method for determining the SR transmission resources according to the BSS or SRG in the SR transmission resource control unit 107 will be described later.

[0119] [Configuration of SR responder] The wireless communication device 200 (SR responder) according to the present embodiment transmits wireless quality information indicating the interference level, SINR, SR transmission availability, etc. for each group (SRG or Non-SRG) or BSS color related to a predetermined BSS color to the wireless communication device 100, and receives an SR signal from the wireless communication device 100.

[0120] The wireless communication device 200 according to the present embodiment has different operations of the wireless quality measurement unit 204 and the wireless quality information generation unit 205 compared to the wireless communication device 200 according to the first embodiment.

[0121] Specifically, the wireless quality measurement unit 204 measures the wireless quality in units of BSS color or SRG. That is, the wireless quality measurement unit 204 measures the reception power or interference level of the reception signal input from the wireless transmission / reception unit 201 for each BSS color or SRG, and outputs the measurement result to the wireless quality information generation unit 205.

[0122] Then, the radio quality information generation unit 205 generates radio quality information for each BSS color or radio quality information for each SRG using the measurement results of the radio quality measured in units of BSS color or SRG.

[0123] [Method for determining whether to transmit SR signal] Next, a method for determining whether to transmit an SR signal in the SR transmission resource control unit 107 of the wireless communication device 100 (SR initiator) will be described in detail.

[0124] The SR transmission resource control unit 107 determines whether to transmit SR based on the radio quality information received from the SR responder.

[0125] [Radio quality information] BSSs that are Non-SRG are managed by different operators from BSSs that are SRG (including its own BSS). Therefore, when the SR initiator applies SR transmission to a Non-SRG OBSS, it is assumed to reduce co-interference to OBSSs other than the target OBSS.

[0126] Therefore, in the present embodiment, the radio quality measurement unit 204 of the SR responder determines the BSS color of the received signal and measures the radio quality (e.g., interference level) of each of SRG and Non-SRG.

[0127] Then, the radio quality information generation unit 205 of the SR responder sets thresholds for SRG and Non-SRG respectively, and determines that SR transmission is possible (i.e., the SR signal can be received) when the interference level of the received signal measured by the radio quality measurement unit 204 is below the threshold, and determines that SR transmission is impossible (i.e., the SR signal cannot be received) when the interference level is above the threshold. That is, the radio quality information indicates the radio quality for each of SRG and Non-SRG. For example, FIG. 11 shows the radio quality information (SR transmission availability information) indicating the transmission availability of the SR signal for SRG and Non-SRG generated in the radio quality information generation unit 205.

[0128] Accordingly, by determining whether to perform SR transmission in consideration of the increase and decrease of the interference level for each of the SRG and Non-SRG depending on the OBSS environment around the SR responder, it is possible to prevent a decrease in the reception success rate of the SR signal at the SR responder and improve the system performance.

[0129] As described above, since the Non-SRG is managed by an operator different from the BSS to which the SR initiator and the SR responder belong, it is desirable that the interference caused by SR transmission to the Non-SRG be small. Therefore, for example, in order to reduce the interference caused by SR transmission to the OBSS that is the Non-SRG, in generating the radio quality information at the SR responder, the threshold value for the interference level of the Non-SRG may be set smaller than the threshold value for the interference level of the SRG. As a result, compared with the SRG, the possibility of applying SR transmission to the Non-SRG is reduced. By doing so, in the Non-SRG, the possibility of being interfered with by SR transmission can be reduced.

[0130] Also, the radio quality information generation unit 205 may prohibit all SR transmissions to the Non-SRG and set a threshold value for the interference level for the SRG. For example, the radio quality information generation unit 205 may not generate radio quality information for the Non-SRG, or may always make it impossible to transmit radio quality information for the Non-SRG. In this case, the SR radio resource control unit 107 of the SR initiator may determine whether SR transmission is possible based on the radio quality information when the received signal is the SRG. Accordingly, the SR initiator can determine whether SR is possible in consideration of only the increase and decrease of the interference level of the SRG depending on the OBSS environment around the SR responder, so that a decrease in the reception success rate of the SR signal at the SR responder can be prevented and the system performance can be improved.

[0131] In addition, the interference given to the SR responder depends on the arrangement of surrounding OBSSs. Depending on the arrangement of OBSSs, the SR responder is assumed to receive strong interference from a specific OBSS. Therefore, the radio quality measurement unit 204 of the SR responder may measure the interference level in units of BSS color (that is, BSS units). Then, the radio quality information generation unit 205 sets an interference level threshold common to all BSS colors, and as shown in FIG. 12, for each BSS color, if the interference level is less than the threshold, it is determined that SR transmission is possible, and if the interference level is equal to or greater than the threshold, it is determined that SR transmission is impossible. That is, the radio quality information indicates the radio quality for each BSS. Thereby, it is possible to determine whether SR is possible in consideration of the increase and decrease of the interference level in individual OBSS units depending on the OBSS environment around the SR responder, so that it is possible to prevent a decrease in the reception success rate of SR signals at the SR responder and improve the system performance.

[0132] Note that the radio quality information notified by the SR responder to the SR initiator is not limited to the information indicating whether the SR signal can be transmitted as shown in FIGS. 11 and 12. For example, radio quality information indicating the interference level of each of the SRG and Non-SRG may be notified. In this case, the SR transmission resource control unit 107 of the SR initiator may determine whether SR transmission is possible based on the interference level indicated in the radio quality information and the set threshold.

[0133] Also, in FIG. 11, the case of using radio quality information for two groups of SRG and Non-SRG has been described, but the radio quality information may use radio quality information for three or more groups (for example, SRG and a plurality of Non-SRG).

[0134] [SR signal transmission resource determination method] Next, the method for determining the SR signal transmission resource in the SR transmission resource control unit 107 of the SR initiator will be described in more detail.

[0135] The SR transmission resource control unit 107 determines whether SR transmission is possible based on the radio quality information received from the SR responder and the BSS color of the received signal (OBSS signal). That is, the SR transmission resource control unit 107 determines whether SR transmission is possible based on the radio quality information for each SRG / Non-SRG or for each BSS color (see, for example, FIGS. 11 or 12), specifically, based on the radio quality information of the group (SRG or Non-SRG) to which the BSS color included in the received signal belongs.

[0136] When the determination result of SR transmission for the BSS color of the received signal indicates that transmission is possible, the SR transmission resource control unit 107 determines the time resource and transmission power resource of the SR signal in the same manner as in Embodiment 1. That is, the SR transmission resource control unit 107 sets the transmission power input from the SR transmission power reduction unit 105 as the transmission power resource. Also, the SR transmission resource control unit 107 sets a time shorter than the packet length of the Trigger-based PPDU (non-SR signal) as the time resource. Further, the SR transmission resource control unit 107 sets a predetermined band corresponding to the transmission data size of the SR signal including the Primary channel as the frequency resource.

[0137] On the other hand, when the determination result of SR transmission for the BSS color of the received signal indicates that transmission is not possible, the SR transmission resource control unit 107 turns off the output from the SR transmission resource control unit 107 or outputs information indicating non-SR transmission to abort the SR transmission.

[0138] The method for determining the transmission resources of the SR signal has been described above.

[0139] [Effect] Thus, in this embodiment, the SR initiator (wireless communication device 100) controls SR transmission in units of SRG / Non-SRG or BSS based on the radio quality information from the SR responder (wireless communication device 200). Thereby, the SR initiator can preferentially apply SR transmission to an OBSS which is a group or BSS capable of SR transmission (for example, a group or BSS with less interference to the SR responder). Therefore, according to this embodiment, in the SR responder, interference from the OBSS to the SR responder can be reduced, the reception success rate of the SR signal can be improved, and the system performance can be improved.

[0140] Also, in this embodiment, the SR initiator does not apply SR transmission to an SRG or BSS for which it is determined that the reception success rate of the SR signal is low in the SR responder. Thereby, it is possible to prevent the SR signal from becoming an interference source for an OBSS that is closer to the SR initiator than the OBSS that is the target of interference reduction and is not the target of interference reduction.

[0141] As described above, it is assumed that Non-SRGs different from the SRG including the BSS to which the SR initiator and the SR responder belong are managed by different operators. In contrast, according to this embodiment, even when the SR initiator performs SR transmission to an OBSS belonging to an SRG different from the BSS to which it belongs, if the interference from the non-SR signal from the OBSS of the Non-SRG is large and decoding errors of the SR signal in the SR responder are likely to occur, the SR transmission is aborted. Thereby, in the Non-SRG, interference caused by SR transmission is eliminated. That is, the SR initiator can control SR transmission so as not to interfere with the surrounding OBSS other than the OBSS targeted for SR transmission in the Non-SRG.

[0142] (Embodiment 3) Regarding the transmission power of the SR signal, the maximum power is derived by Equation (2) to reduce interference to OBSS, but the minimum power is not determined. Therefore, depending on the values of SRP and RSSI obtained from the Trigger frame transmitted by OBSS, the transmission power of the SR signal may decrease, and the reception success rate at the SR responder may decline.

[0143] Therefore, in this embodiment, a method for guaranteeing the reception quality of the SR signal at the SR responder and improving the reception success rate of the SR signal at the SR responder will be described.

[0144] [Configuration of SR initiator]

[0145] FIG. 13 is a block diagram showing a configuration example of the wireless communication device 300 according to this embodiment. The wireless communication device 300 (SR initiator) according to this embodiment determines whether SR transmission is possible based on information obtained from the Trigger frame from OBSS (for example, SRP and RSSI) and radio quality information from the SR responder, and transmits an SR signal within a predetermined period when SR transmission is possible.

[0146] In FIG. 13, the same components as those in Embodiment 1 (FIG. 4) are denoted by the same reference numerals, and the description thereof is omitted. Specifically, the wireless communication device 300 does not include the SR transmission power reduction unit 105 with respect to the wireless communication device 100 according to Embodiment 1, and the operation of the SR transmission resource control unit 301 is different.

[0147] In addition, the radio quality information held by the radio quality information holding unit 106 is information indicating the SINR at the SR responder when communicating from the SR initiator (wireless communication device 300) to the SR responder (wireless communication device 200).

[0148] Specifically, the SR transmission resource control unit 301 uses the SRP [dBm] included in the Trigger frame input from the decoding unit 104 and the RSSI of the Trigger frame (RSSI trigger frame ) input from the received power measurement unit 102 to calculate the transmission power of the SR signal (corresponding to the allowable power described later. That is, the transmission power calculated from the SRP).

[0149] Also, the SR transmission resource control unit 301 calculates the guaranteed power that satisfies a predetermined PER (Packet Error Rate) in the SR responder based on the radio quality information (SINR information) acquired from the radio quality information holding unit 106.

[0150] Then, when the transmission power calculated from the SRP does not satisfy the guaranteed power (when it is less than the guaranteed power), the SR transmission resource control unit 301 determines that SR transmission is impossible and aborts the SR transmission.

[0151] On the other hand, when the transmission power calculated from the SRP satisfies the guaranteed power (when the transmission power calculated from the SRP is greater than the guaranteed power), the SR transmission resource control unit 301 determines that SR transmission is possible and determines the transmission resource of the SR signal. Specifically, the SR transmission resource control unit 301 determines the time resource and the frequency resource in the same manner as in Embodiment 1 or 2. That is, the SR transmission resource control unit 301 sets a time shorter than the packet length of the Trigger-based PPDU (non-SR signal) as the time resource, and sets a predetermined band corresponding to the transmission data size of the SR transmission signal including the Primary channel as the frequency resource.

[0152] Also, the SR transmission resource control unit 301 determines the transmission power resource based on the transmission power and the guaranteed power calculated from the SRP. Details of the method for determining the SR transmission resource (transmission power resource) in the SR transmission resource control unit 301 will be described later.

[0153] [Configuration of SR responder] Since the SR responder according to this embodiment has the same basic configuration as the wireless communication device 200 according to Embodiment 1, it will be described with reference to FIG. 5.

[0154] The wireless communication device 200 (SR responder) according to this embodiment uses the received signal from the SR initiator to transmit wireless quality information indicating SINR or the like to the wireless communication device 100, and receives the SR signal from the wireless communication device 100.

[0155] The operation of the wireless quality measurement unit 204 and the wireless quality information generation unit 205 of the wireless communication device 200 according to this embodiment is different from that of the wireless communication device 200 according to Embodiment 1.

[0156] Specifically, the wireless quality measurement unit 204 measures the reception quality (for example, SINR) from the received signal of the SR initiator input from the wireless transmission / reception unit 201, and outputs the measurement result to the wireless quality information generation unit 205.

[0157] The wireless quality information generation unit 205 generates a management frame or a control frame addressed to the SR initiator including the measurement result including SINR input from the wireless quality measurement unit 204, and outputs it to the modulation unit 206.

[0158] [Method for Determining Transmission Power of SR Transmission Signal] Next, the method for determining the transmission power resource in the SR transmission resource control unit 301 will be described in more detail.

[0159] When the SR initiator performs SR transmission to the OBSS, depending on the transmission power of the SR signal obtained by the interference reduction process for the OBSS (that is, the transmission power calculated from the SRP), due to the influence of the interference on the SR responder based on the arrangement of the surrounding OBSSs, it is assumed that the received SINR of the SR signal in the SR responder does not satisfy the required quality and the reception success rate decreases.

[0160] Therefore, the SR transmission resource control unit 301 of the SR initiator determines the transmission power of the SR signal based on the reception quality indicated by the radio quality information received from the SR responder. Here, the reception quality indicated by the radio quality information is, for example, the SINR when the SR initiator transmits to the SR responder at a predetermined power. Specifically, the SR transmission resource control unit 301 uses the SINR information included in the radio quality information to calculate the transmission power (guaranteed power) required for the PER of a predetermined MCS (for example, the most robust MCS) to meet the target value.

[0161] Then, the SR transmission resource control unit 301 uses the calculated guaranteed power, the SRP [dBm] included in the Trigger frame, and the RSSI of the Trigger frame (RSSI trigger frame ) input from the received power measurement unit 102 to determine the transmission power (TXPWR SR initiator ) of the SR signal as follows.

[0162] To suppress the interference to the OBSS within the allowable value, the SR transmission resource control unit 301 needs to suppress the transmission power of the SR signal to be less than the power (referred to as the allowable power (TXPWR Allowed )) calculated according to the following formula (3). TXPWR Allowed = SRP - RSSI trigger frame …(3)

[0163] Specifically, when the allowable power is greater than the guaranteed power (Guaranteed power < TXPWR Allowed ), the SR transmission resource control unit 301 sets the transmission power (TXPWR SR initiatorSet it within the range shown in Equation (4.1) (a range greater than the guaranteed power and less than the allowable power). In this case, the SR initiator can use a transmission power that minimizes the interference to the OBSS that is the target of SR transmission while ensuring the reception quality in the SR responder. As a result, the interference to the OBSS that is not the target of SR transmission can also be reduced, so the transmission opportunity of the OBSS can be increased and the system performance is improved.

Number

[0164] Also, when the allowable power is less than or equal to the guaranteed power (Guaranteed power ≧ TXPWR Allowed ), since the transmission power of the SR signal does not satisfy the guaranteed power, the SR transmission is aborted (prohibited). As a result, the SR initiator can avoid SR transmission with a low reception success rate in the SR responder. Therefore, a decrease in the reception success rate of the SR signal can be prevented and the system performance is improved.

[0165] [Effect] As described above, in this embodiment, the SR initiator performs SR transmission with a transmission power that guarantees the reception quality of the SR signal in the SR responder. That is, the SR initiator does not perform SR transmission when it cannot guarantee the reception quality of the SR signal in the SR responder. In this way, the SR initiator can determine the transmission resource (transmission power) of the SR signal according to the radio channel condition (for example, SINR) in the SR responder and transmit the SR signal. Therefore, according to this embodiment, in the SR responder, by reducing the interference to the SR responder by the OBSS and ensuring the reception quality of the SR signal in the SR responder, the reception success rate of the SR signal can be improved and the system performance can be improved.

[0166] Also, in the present embodiment, the SR initiator does not transmit an SR signal in a band where it is determined that the reception success rate of the SR signal is low in the SR responder. As a result, in a band where the SR signal is not transmitted, it is possible to prevent the SR signal from becoming an interference source for an OBSS that is closer to the SR initiator than the OBSS that is the target of interference reduction and is not the target of interference reduction.

[0167] As described above, each embodiment of the present disclosure has been described.

[0168] (Other embodiments) (1) You may apply by combining at least two of Embodiment 1, Embodiment 2, and Embodiment 3. For example, as described in Embodiment 2, the SR initiator determines whether to transmit an SR signal in units of SRGs, and further, in an SRG capable of transmitting an SR signal, as described in Embodiment 1, it may determine whether to transmit an SR signal in units of a predetermined band. Also, for example, as described in Embodiment 1 and / or Embodiment 2, the SR initiator determines whether to transmit an SR signal, and as described in Embodiment 3, it may transmit the SR signal so as to satisfy the guaranteed power.

[0169] (2) In the wireless communication device 100 (see FIG. 4) according to Embodiment 1 and Embodiment 2, the processing of the SR transmission resource control unit 107 (that is, the determination of the transmission resource) and the processing of the SR transmission power reduction unit 105 (that is, the reduction of the transmission power based on the SRP) may be in either order. For example, when the SR transmission resource control unit 107 determines that SR transmission is impossible (SR transmission is aborted) based on the radio quality information, the SR transmission power reduction unit 105 does not perform the processing. As a result, the processing amount in the wireless communication device 100 can be reduced.

[0170] (3) The SR responder may update the radio quality information when receiving a BSS signal or an OBSS signal, and notify the radio quality information to the STAs within the BSS to which the SR responder belongs.

[0171] (4) In the above-described embodiment, the case where the SR initiator is a STA and the SR responder is an AP has been described, but the present invention is not limited thereto. For example, even when the SR initiator is an AP and the SR responder is a STA, the above-described embodiment can be applied, and the same effects can be obtained.

[0172] Note that the operation when the SR initiator is an AP and the SR responder is a STA is the same as the operation example shown in FIG. 6. That is, similar to FIG. 6, the SR responder (STA) transmits radio quality information to the SR initiator (AP) at a predetermined period or at a predetermined timing. The SR initiator (AP) determines whether SR transmission is possible based on the radio quality information from the SR responder (STA), and when SR transmission is possible, performs SR transmission using available transmission resources.

[0173] Note that the SR initiator (AP) may transmit a signal (radio quality information request signal) for requesting radio quality information to the STAs within the BSS to which it belongs (not shown). The STA that has received the radio quality information request signal transmits a response signal including the radio quality information to the SR initiator (AP). For example, the SR initiator (AP) may use a Trigger frame (Trigger type is BQRP (Bandwidth Query Report Poll) Trigger frame) that requests the STA to transmit a BQR (Bandwidth Query Report) as the radio quality information request signal and transmit it to the STAs within the BSS to which it belongs. In this case, the STA transmits the BQR as the radio quality information as a response signal to the radio quality information request signal. In this way, by using the means for acquiring radio quality information already defined in 11ax, the process of requesting radio quality information can be easily realized.

[0174] Also, even when both the SR initiator and the SR responder are STAs, the above-described embodiment can be applied, and the same effects can be obtained.

[0175] (5) In the above embodiment, SRP-based SR (DSRP_PPDU-based SR) using an OBSS Trigger frame was described as an example, but the above embodiment can also be applied to other SRP-based SRs, and the same effects can be obtained.

[0176] When applying the above embodiment to other SRP-based SRs, the method for obtaining SRP and the method for measuring RSSI are different from those of DSRP_PPDU-based SR. Note that other SRP-based SRs include, for example, TSRP (Trigger-based SRP)_PPDU-based SR using a PPDU that is not an OBSS Trigger frame, ULSRP (Uplink SRP)_PPDU-based SR using an OBSS beacon and response frame, or DLSRP (Downlink SRP)_PPDU-based SR using an OBSS CTS (Clear to Send) (see, for example, Non-Patent Document 1). Hereinafter, these SRP-based SR methods will be referred to as "SRP-based SR using a preceding signal".

[0177] FIG. 14 is a sequence diagram showing an operation example of SRP-based SR using a preceding signal. In FIG. 14, the same operations as those in FIG. 6 are denoted by the same reference numerals, and the description thereof is omitted.

[0178] In FIG. 14, the OBSS AP transmits a preceding signal to the OBSS STA (ST301). The preceding signal is a signal having the same BSS color as the signal transmitted by the OBSS STA. Specifically, the preceding signal is a PPDU that cannot be distinguished from a Trigger frame, a beacon frame, a CTS frame, a BA (Block ACK) frame, or an ACK (Acknowledgement) frame.

[0179] In ST301, the SR initiator receives the preceding signal transmitted by the OBSS AP, measures the RSSI for each frame type of the received preceding signal, and stores it.

[0180] Next, the SR initiator receives a non-SR signal transmitted by the OBSS STA to the OBSS AP, and obtains the SRP and the packet length of the non-SR signal based on the non-SR signal (ST302). Further, the SR initiator identifies the PPDU format in the non-SR signal, and obtains the RSSI of a signal that satisfies a predetermined condition (for example, being a frame type corresponding to the PPDU format) from the stored RSSIs of the preceding signals. Then, the SR initiator determines the transmission power of the SR signal for reducing interference to the OBSS AP (for example, refer to Equation (2)) using the obtained SRP and RSSI (ST303). Also, the SR initiator determines the SR transmission period (SRP opportunity) based on the packet length of the obtained non-SR signal (ST304).

[0181] That is, in FIG. 14, the SR initiator is different from FIG. 6 in that it obtains the SRP and the packet length of the non-SR signal from the non-SR signal transmitted from the OBSS, and obtains the RSSI measured from the preceding signal according to the format of the non-SR signal.

[0182] FIG. 15 is a block diagram showing a configuration example of a wireless communication device 400 which is an SR initiator that performs SRP-based SR using a preceding signal. In FIG. 15, the same components as those in Embodiment 1 (FIG. 4) are denoted by the same reference numerals, and the description thereof is omitted. Specifically, the wireless communication device 400 is different from FIG. 4 in that it includes a received power holding unit 401.

[0183] The received power holding unit 401 acquires the RSSI measured using the preceding signal of the OBSS from the received power measurement unit 102 and stores it for a predetermined period. Further, the received power holding unit 401 acquires the BSS color, data format, and SRP information obtained from the non-SR signal of the OBSS from the decoding unit 104 and stores them for a predetermined period.

[0184] Then, when a PPDU having a predetermined SRP is input, the received power holding unit 401 outputs the RSSI of the preceding signal that satisfies a predetermined condition corresponding to the format of the input PPDU to the SR transmission power reduction unit 105. On the other hand, when a signal having no predetermined SRP is input, or when the RSSI of the preceding signal that satisfies the predetermined condition is not held, the received power holding unit 401 stores the information included in the input signal. In this case, the SR initiator (for example, the SR control unit) aborts the SR transmission.

[0185] (6) In the above embodiment, the description has been made on the premise of SRP-based SR. However, even in the case of OBSS PD-based SR, the above embodiment can be applied and the same effects can be obtained.

[0186] FIG. 16 is a sequence diagram showing an operation example of OBSS PD-based SR. In FIG. 16, the same operations as those in FIG. 6 are denoted by the same reference numerals, and the description thereof is omitted.

[0187] In FIG. 16, the OBSS STA transmits a non-SR signal to the OBSS AP (ST401). At this time, the SR initiator is receiving the non-SR signal transmitted from the OBSS STA to the OBSS AP.

[0188] Based on the BSS color of the non-SR signal transmitted by the OBSS STA, the SR initiator determines whether the OBSS is an SRG or a Non-SRG, and the received power of the non-SR signal is the OBSS_PD determined based on the following formula (5). Threshold When the received power is as follows, the transmission power of the SR signal is determined (ST402). At this time, the SR initiator does not consider the interference tolerance value of the OBSS AP.

Equation

[0189] In formula (5), OBSS_PD Threshold_min is the minimum value taken by OBSS_PD Threshold and OBSS_PD Threshold_max is the maximum value taken by OBSS_PD Threshold TXPWR ref is the reference transmission power, and TXPWR is the SR transmission power.

[0190] Next, the SR initiator determines the transmission resource of the SR signal for which the desired reception quality can be expected based on the radio quality information regarding the predetermined transmission resource received from the SR responder (ST403). Here, based on the operations and formula (5) described in Embodiment 3, the SR transmission power is represented by the following formulas (6.1) and (6.2).

Equation

[0191] In the case of formula (6.1), if the reception level from the OBSS (OBSS_PD level ) is less than or equal to the minimum value of the OBSS level (OBSS_PD min ), the maximum SR transmission power (TXPWR max ) only needs to satisfy a value greater than the guaranteed power. On the other hand, in the case of formula (6.2), if the reception level from the OBSS is greater than the maximum value of the OBSS PD threshold (OBSS_PD max) If a value within the range of the maximum value and the minimum value is adopted, the SR transmission power is defined within a range of values that is greater than the guaranteed power and less than the reference transmission power. Also, if equations (6.1) and (6.2) are not satisfied, the SR initiator aborts the SR transmission.

[0192] That is, in the OBSS PD-based SR, in terms of the two points that the SR initiator does not perform interference reduction processing for a specific OBSS based on the information obtained from the signal of the OBSS AP as in the above-described embodiment, and the power control method (equations (6.1) and (6.2)) of Embodiment 3, the operation is different from that of the SRP-based SR described in the above-described embodiment.

[0193] (7) Also, in the above-described embodiment, the case where RSSI is used as an example of the received power has been described, but the parameter representing the received power is not limited to RSSI. Also, the case where SINR is used as an example of the reception quality when communicating from the SR initiator to the SR responder has been described, but the parameter representing the reception quality is not limited to SINR.

[0194] (8) This disclosure can be implemented by software, hardware, or software in cooperation with hardware. Each functional block used in the description of the above embodiments can be realized, partially or wholly, as an LSI which is an integrated circuit, and each process described in the above embodiments can be controlled, partially or wholly, by one LSI or a combination of LSIs. The LSI may be composed of individual chips, or may be composed of one chip so as to include part or all of the functional blocks. The LSI may be provided with data input and output. Depending on the degree of integration, the LSI may also be referred to as an IC, a system LSI, a super LSI, or an ultra LSI. The technique of integrating into a circuit is not limited to LSI, and may be realized by a dedicated circuit, a general-purpose processor, or a dedicated processor. Also, after manufacturing the LSI, an FPGA (Field Programmable Gate Array) which can be programmed, or a reconfigurable processor which can reconfigure the connection and setting of circuit cells inside the LSI may be used. This disclosure may be realized as digital processing or analog processing. Furthermore, if a technique of integrating into a circuit which replaces the LSI appears due to the progress of semiconductor technology or another derived technology, naturally, the integration of functional blocks may be performed using that technology. The application of biotechnology etc. is possible as a possibility.

[0195] This disclosure can be implemented in all kinds of devices, apparatuses, systems having a communication function (collectively referred to as communication apparatuses). Non-limiting examples of communication apparatuses include telephones (mobile phones, smartphones, etc.), tablets, personal computers (PCs) (laptops, desktops, notebooks, etc.), cameras (digital still / video cameras, etc.), digital players (digital audio / video players, etc.), wearable devices (wearable cameras, smartwatches, tracking devices, etc.), game consoles, digital book readers, telehealth / telemedicine (remote healthcare / medical prescription) devices, vehicles or mobile transportation means with a communication function (automobiles, airplanes, ships, etc.), and combinations of the above various apparatuses.

[0196] The communication device is not limited to being portable or movable, and includes all kinds of devices, apparatuses, and systems that are not portable or are fixed, such as smart home devices (home appliances, lighting devices, smart meters or measuring devices, control panels, etc.), vending machines, and all other "Things" that can exist on the IoT (Internet of Things) network.

[0197] Communication includes data communication by cellular systems, wireless LAN systems, communication satellite systems, etc., as well as data communication by combinations of these.

[0198] In addition, the communication device also includes devices such as controllers and sensors that are connected or coupled to a communication device that executes the communication function described in the present disclosure. For example, controllers and sensors that generate control signals and data signals used by the communication device that executes the communication function of the communication device are included.

[0199] In addition, the communication device includes infrastructure facilities, such as base stations, access points, and all other devices, apparatuses, and systems that communicate with or control the above-mentioned various devices.

[0200] The wireless communication device of the present disclosure includes a control circuit that determines a transmission resource of an SR (Spatial Reuse) signal transmitted by SR with respect to a second BSS other than the first BSS based on wireless quality information transmitted from other wireless communication devices within the first BSS, and a transmission circuit that transmits the SR signal using the transmission resource.

[0201] In the wireless communication device of the present disclosure, the control circuit determines a band in which the SR signal can be transmitted based on the wireless quality information, the transmission circuit transmits the SR signal in the band in which the SR signal can be transmitted, and does not transmit the SR signal in a band other than the band in which the SR signal can be transmitted.

[0202] In the wireless communication device of the present disclosure, when the control circuit transmits the SR signal during a period obtained based on the signal from the second BSS, the control circuit determines the transmission resource, and when the SR is not transmitted during the period, the control circuit does not determine the transmission resource.

[0203] In the wireless communication device of the present disclosure, the wireless quality information indicates the wireless quality for each predetermined band.

[0204] In the wireless communication device of the present disclosure, the predetermined band is a band in units of RUs (Resource Units).

[0205] In the wireless communication device of the present disclosure, the predetermined band is a band in units of 20 MHz.

[0206] In the wireless communication device of the present disclosure, the wireless quality information indicates any one of whether the SR signal can be received in the other wireless communication device, whether the interference level in the other wireless communication device is lower than a threshold value, the interference level in the other wireless communication device, and the reception quality when communicating from the wireless communication device to the other wireless communication device.

[0207] In the wireless communication device of the present disclosure, the wireless quality information indicates the wireless quality for each BSS.

[0208] In the wireless communication device of the present disclosure, the wireless quality information indicates the wireless quality for BSSs belonging to a first group including the first BSS and the wireless quality for BSSs belonging to a second group different from the first group.

[0209] In the wireless communication device of the present disclosure, the wireless quality information includes reception quality when communicating from the wireless communication device to the other wireless communication device, and the control circuit calculates a first transmission power that satisfies a predetermined error rate in the other wireless communication device based on the reception quality, calculates a second transmission power based on the signal from the second BSS, and determines transmission of the SR signal when the second transmission power is greater than the first transmission power.

[0210] In the wireless communication device of the present disclosure, the transmission power of the SR signal is greater than the first transmission power and less than the second transmission power.

[0211] The wireless communication method of the present disclosure determines a transmission resource of an SR (Spatial Reuse) signal transmitted by SR for a second BSS other than the first BSS based on wireless quality information transmitted from another wireless communication device within a first BSS (Basic Service Set), and transmits the SR signal using the transmission resource.

[0212] The disclosure contents of the specification, drawings, and abstracts included in the Japanese application of Japanese Patent Application No. 2018-035456 filed on February 28, 2018 are all incorporated herein by reference.

Industrial Applicability

[0213] One aspect of the present disclosure is useful for a wireless communication system.

Explanation of Signs

[0214] 100, 200, 300, 400 Wireless communication device 101, 201 Wireless transmission / reception unit 102 Reception power measurement unit 103, 202 Demodulation unit 104, 203 Decoding unit 105 SR transmission power reduction unit 106 Wireless quality information holding unit 107, 301 SR transmission resource control unit 108 Encoding unit 109 Preamble Generation Unit 110, 206 Modulation Unit 204 Wireless Quality Measurement Unit 205 Wireless Quality Information Generation Unit 401 Received Power Holding Unit

Claims

1. a first communication device, a receiver that receives control information related to SR (Spatial Reuse) transmission from a second communication device; a circuit for determining transmission resources relating to at least one of time resources, frequency resources, and transmit power resources based on the control information; a transmitting circuit configured to transmit data to a third communication device based on the transmission resource; A first communication device comprising:

2. The control information includes a transmission power parameter determined by the second communication device based on a measurement result obtained by the second communication device. The first communication device according to claim 1 .

3. The control information is transmitted in a trigger frame. The first communication device according to claim 1 .

4. The control information is transmitted from the second communication device to the first communication device at a predetermined timing or periodically. The first communication device according to claim 1 .

5. The control information includes information regarding a maximum value of the transmission power of the first communication device. The first communication device according to claim 1 .

6. The data is transmitted from the first communication device to the third communication device at a transmission power determined based on the control information. The first communication device according to claim 1 .

7. The control information includes information about results measured on one or more resource units (RUs). The first communication device according to claim 1 .

8. The first communication device receiving control information related to Spatial Reuse (SR) transmission from a second communication device; determining transmission resources relating to at least one of time resources, frequency resources, and transmission power resources based on the control information; transmitting data to a third communication device based on the transmission resource; A wireless communication method comprising:

9. The control information includes a transmission power parameter determined by the second communication device based on a measurement result obtained by the second communication device. The communication method according to claim 8.

10. The control information is transmitted in a trigger frame. The communication method according to claim 8.

11. The control information is transmitted from the second communication device to the first communication device at a predetermined timing or periodically. The communication method according to claim 8.

12. The control information includes information regarding a maximum value of the transmission power of the first communication device. The communication method according to claim 8.

13. The data is transmitted from the first communication device to the third communication device at a transmission power determined based on the control information. The communication method according to claim 8.

14. The control information includes information about results measured on one or more resource units (RUs). The communication method according to claim 8.

15. 1. An integrated circuit for use in a first communication device, comprising: receiving control information related to Spatial Reuse (SR) transmission from a second communication device; determining transmission resources relating to at least one of time resources, frequency resources, and transmit power resources based on the control information; transmitting data to a third communication device based on the transmission resource; An integrated circuit that controls

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