Communication equipment and communication methods

Abstract

The present invention provides a communication device that performs multilink and multiuser communication.　This communication device comprises: a communication unit that is capable of performing wireless communication via a plurality of links; a communication processing unit that performs processing for transmitting data simultaneously to a plurality of reception-side communication devices; and a control unit that performs a control to transmit data using an optimum link for each of the plurality of reception-side communication devices. The control unit, via a link for which a transmission opportunity has been acquired, transmits a trigger request signal for requesting information related to a reception opportunity to the plurality of reception-side communication devices, and performs a control to determine an optimum link for each of the reception-side communication devices on the basis of request response signals from the plurality of reception-side communication devices.

Description

Technical Field

[0001] The technology disclosed in this specification (hereinafter referred to as "this disclosure") relates to a communication device and a communication method for performing wireless communication.

Background Art

[0002] With the increasing use of wireless LAN (Local Area Network) systems and the increasing capacity of content, a situation is arising where using only the channels of one frequency band is insufficient for communication of a predetermined amount of data. Therefore, as a technical study for the successor standard to IEEE802.11ax, in the IEEE task group TG be, a method of performing higher-density data communication by using multiple frequency bands (links) in parallel, specifically, a multi-link operation (MLO) technology for collectively transmitting a lump of content by using multiple frequency bands (links) is being studied.

[0003] In this multi-link operation, a technology for communication is required that regards multiple frequency bands (links) as one transmission path. In this technology, as a device equipped with multiple wireless communication units so that transmission and reception can be performed simultaneously on all links, a device of Enhanced Multi-Link Multi Radio (EMLMR) is assumed. However, as a configuration of a communication device that can only transmit or receive on one link, a device of Enhanced Multi-Link Single Radio (EMLSR) is also assumed. In the network of an actual wireless LAN system, it is also assumed that these two types are mixed.

[0004] In the conventional multi-link operation, a configuration is assumed in which both the access point and the communication terminal perform communication simultaneously using the same multiple links.

[0005] On the other hand, multi-user multiplexing communication is already in practical use in existing wireless LAN systems. For example, wireless LAN systems have been proposed that transmit more data by multiplexing and transmitting multiple streams simultaneously on a single frequency channel. Specifically, an access point can assign arbitrary resources to multiple communication terminals and transmit them, and each receiving communication terminal can receive the desired data by separating and decoding each resource. In other words, in conventional downlink multi-user (DL MU) communication, even if data is unilaterally multiplexed and transmitted from the access point, all communication terminals on that frequency channel (link) can receive the data and separate it into user-specific data based on the information contained in the header information of the received frame.

[0006] IEEE 802.11ax specifies that, regarding resource allocation in multiplexed communication, when implementing uplink and downlink multi-user multiplexed communication, the access point (AP) notifies a Bandwidth Query Report Poll (BQRP) Trigger Frame, and in response, the communication terminal (STA) sends back a Bandwidth Query Report (BQR) containing available channel information in the Bandwidth Query Report Control Subfield. The AP then allocates resources based on the BQR from the STA (see, for example, Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0007] [Non-Patent Document 1] IEEE802.11ax contribution (IEEE802.11-18 / 0031r0) [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] The purpose of this disclosure is to provide a communication device and a communication method for performing wireless communication with multiple users using multiple frequency bands. [Means for solving the problem]

[0009] This disclosure has been made in consideration of the above issues, and its first aspect is: A communication unit capable of wireless communication via multiple links, A communication processing unit that performs the process of simultaneously transmitting data to multiple receiving communication devices, A control unit that performs control to transmit data using the optimal link for each of the multiple receiving communication devices, It is a communication device equipped with the following features.

[0010] The control unit transmits a trigger request signal to the plurality of receiving communication devices requesting information about the receiving opportunity on the link where a transmission opportunity has been acquired, and controls the device to determine the optimal link for each receiving communication device based on the request response signals from the plurality of receiving communication devices.

[0011] Furthermore, the control unit controls the transmission of an allocation signal that includes information about the link assigned to each receiving communication device and information about multi-user multiplex communication.

[0012] Furthermore, the control unit controls the simultaneous transmission of data to the multiple receiving communication devices using the multiple links, based on the link information assigned to each receiving communication device and the information regarding multi-user multiplex communication.

[0013] Furthermore, a second aspect of this disclosure is a communication method in a communication device capable of wireless communication over multiple links, The steps include determining the optimal link for each of the plurality of receiving communication devices, The steps include: using the optimal link for each receiving communication device to simultaneously transmit data to multiple receiving communication devices; This is a communication method that has [a certain characteristic].

[0014] Furthermore, the third aspect of this disclosure is, A communication unit capable of wireless communication via multiple links, A communication processing unit that processes data addressed to itself from among data simultaneously transmitted from a transmitting communication device to multiple receiving communication devices, A control unit that notifies the transmitting communication device of its available link reception opportunities and controls the receiving of data from the transmitting communication device on the specified link, It is a communication device equipped with the following features.

[0015] In response to receiving a trigger request signal from the transmitting communication device, the control unit controls all links that have been able to acquire a reception opportunity to send back a request response signal.

[0016] Furthermore, the control unit controls the link from which the request response signal was transmitted to wait for the transmission of data from the transmitting communication device to be received by multiple receiving communication devices.

[0017] Furthermore, a fourth aspect of this disclosure is a communication method in a communication device capable of wireless communication over multiple links, The steps include notifying the transmitting communication device of information regarding the opportunity to receive links that are available to it, The steps include: receiving data addressed to oneself from among data simultaneously transmitted from the transmitting communication device to multiple receiving communication devices via a link specified by the transmitting communication device; This is a communication method that has [a certain characteristic]. [Effects of the Invention]

[0018] According to this disclosure, it is possible to provide a communication device and a communication method that perform wireless communication with multiple users using multiple links.

[0019] The effects described herein are merely illustrative, and the effects brought about by this disclosure are not limited to those described herein. Furthermore, this disclosure may produce additional effects beyond those described above.

[0020] Further objects, features, and advantages of the present disclosure will become apparent from the more detailed description based on the embodiments described below and the accompanying drawings.

Brief Description of the Drawings

[0021] [Figure 1] FIG. 1 is a diagram showing the network situation of a wireless LAN system. [Figure 2] FIG. 2 is a diagram showing an example of a frequency band and channel allocation used in a wireless LAN system. [Figure 3] FIG. 3 is a diagram showing an example of applying downlink multi-user multiplexing communication (DLMU) to MLO. [Figure 4] FIG. 4 is a diagram showing a modified example of applying downlink multi-user multiplexing communication (DLMU) to MLO. [Figure 5] FIG. 5 is a diagram showing another modified example of applying downlink multi-user multiplexing communication (DLMU) to MLO. [Figure 6] FIG. 6 is a diagram showing a modified example of performing uplink multi-user multiplexing communication (ULMU) after downlink multi-user multiplexing communication (DLMU) to which MLO is applied. [Figure 7] FIG. 7 is a diagram showing an example of the utilization detection status of multi-link at AP10. [Figure 8] FIG. 8 is a diagram showing an example of the utilization detection status of multi-link at STA11 under AP10. [Figure 9] FIG. 9 is a diagram showing an example of the utilization detection status of multi-link at STA12 under AP10. [Figure 10] FIG. 10 is a diagram showing an example of the utilization detection status of multi-link at STA13 under AP10. [Figure 11] FIG. 11 is a diagram showing an example of the utilization detection status of multi-link at STA14 under AP10. [Figure 12]Figure 12 shows an example in which downlink multi-user communication is applied to multilink in AP10. [Figure 13] Figure 13 shows an example in which downlink multi-user communication is applied to multilink in STA11 under AP10. [Figure 14] Figure 14 shows an example in which downlink multi-user communication is applied to multilink in STA12 under AP10. [Figure 15] Figure 15 shows an example in which downlink multi-user communication is applied to multilink in STA13 under AP10. [Figure 16] Figure 16 shows an example of applying downlink multi-user communication to the multilink of an EMLSR device. [Figure 17] Figure 17 shows an example sequence of downlink multi-user multiplexed communication for each link. [Figure 18] Figure 18 shows an example sequence of downlink multi-user multiplexed communication for each link. [Figure 19] Figure 19 shows the functional configuration of the wireless communication device 1900. [Figure 20] Figure 20 shows the internal configuration of the wireless communication module 1905. [Figure 21] Figure 21 shows the configuration of the management framework required for setting up the MLO. [Figure 22] Figure 22 shows the frame format corresponding to each value listed in the Type field of the MU MLO information element. [Figure 23] Figure 23 shows the structure of the MU MLO Information Element field in a Downlink Trigger Request (TR) frame. [Figure 24] Figure 24 shows the structure of the MU MLO Information Element field in a DL Request Response (RR) frame. [Figure 25] Figure 25 shows the structure of the MU MLO Information Element field in the DL Allocation (AL) frame. [Figure 26] Figure 26 shows the configuration of the downlink Block Acknowledgement (BA) frame. [Figure 27] Figure 27 is a flowchart illustrating the actions performed by an access point during downlink communication. [Figure 28] Figure 28 is a flowchart illustrating the actions performed by an access point during downlink communication. [Figure 29] Figure 29 is a flowchart illustrating the actions performed by a communication terminal during downlink communication. [Figure 30] Figure 30 is a flowchart illustrating the actions performed by a communication terminal during downlink communication. [Modes for carrying out the invention]

[0022] The present disclosure will be described below in the following order, with reference to the drawings.

[0023] A. Overview B. Network Configuration Downlink multi-user multiplex communication applied to C.MLO D.AP and STA Multilink Usage Detection Status E. An example of applying downlink multi-user communication to multilink. F. Sequence of downlink multi-user multiplexing communications for each link G. Configuration of wireless communication equipment H. Frame Configuration I. Example of Downlink Communication Operation J. Effect

[0024] A. Overview From the perspective of ensuring compatibility with conventional wireless LAN systems, there are problems such as the inability to transmit using one of the multiple frequency bands (links) if the transmission path is in use, and the fact that the timing of when transmission becomes possible differs for each frequency band (link). In addition, although it is necessary to set a random backoff for each frequency band (link), there is a problem that even if the transmission path is free, transmission may not start simultaneously on each frequency band (link) depending on the random backoff setting.

[0025] Furthermore, even if a link is available on one communication device, it may not be available on another, which presents a problem in simultaneously sending data to multiple communication devices. For example, if an access point uses three links, from the first to the third, for multilink operation, one communication terminal connected to that access point may have the first and second links available, while another communication terminal may have the first and third links available.

[0026] Regarding multilink operation, there will be devices on the network that are Enhanced Single Radio devices, meaning they cannot receive multiple links simultaneously. Therefore, it is necessary to establish technologies that are consistent with the operation of these communication devices.

[0027] In conventional downlink multi-user communication, all receiving devices are supposed to receive on that frequency channel (link). However, if there are other overlapping BSSs (Blockside Storage Systems) or OBSSs (Optical Network Systems) in the vicinity, there is a high probability that some receiving devices in multilink operation will not be able to correctly receive the header information of the received frame.

[0028] However, the BQRP Trigger Frame, standardized in IEEE 802.11ax, has a problem in that it is only configured to request a BQR response from the STA, and cannot notify the STA of detailed parameters.

[0029] Furthermore, the BQR Control Subfield, standardized in IEEE 802.11ax, has the problem that it can only send short pieces of information back, and can only transmit information for about eight consecutive available channels.

[0030] Furthermore, channel availability is determined based on the detection results of CCA (Clear Channel Assessment). Therefore, even if the Network Allocation Vector (NAV) is set when a signal from OBSS STA is received, if no signal is actually detected, the system will mistakenly determine that the channel is available. This leads to a problem where, when the access point assigns the channel, the NAV is actually set and transmission is not possible.

[0031] This document summarizes the challenges involved in establishing multi-user communication in multilink operations.

[0032] First, there is a problem in that when a transmitting device acquires transmission rights, it cannot determine at that point which links are available to each of the multiple receiving devices. In other words, if a transmitting device acquires transmission rights (TXOP) on all or more links and attempts to transmit data without knowing the availability of these links at each receiving device, the receiving devices will not be able to receive the data correctly.

[0033] Furthermore, Enhanced Single Radio devices have difficulty operating on multiple links, which means they cannot receive signals on multiple links simultaneously in multilink operation. Therefore, Enhanced Single Radio devices need to prioritize the use of available links.

[0034] Therefore, during multilink operation, multiple receiving communication devices acting as multi-users must each notify the transmitting communication device of the Receive Opportunity (RXOP) information for available links. The transmitting communication device must then determine which link to assign data destined for each receiving communication device to, based on the RXOP status of each device.

[0035] Next, this disclosure describes a method by which a receiving communication device exchanges RXOP information when performing multi-user communication in multilink operation, and a method by which an AP acting as a TXOP holder recognizes the RXOP for each STA, determines the availability for each STA, and implements control to appropriately allocate each link in the multilink.

[0036] Downlink multi-user communication using multilink operation (MLO) from an access point (AP) to multiple subordinate communication terminals (STAs) is performed using the following procedure:

[0037] (1) The AP sends a MU-MLO Trigger Request to each receiving STA via a transmittable link. (2) Each STA sends a MU-MLO Request Response to the AP, which includes information about the RXOP in the multilink. (3) The AP sets the downlink resource to be used for reception for each STA based on the RXOP information received from each STA that will be the receiving side. (4) The AP sends MU-MLO Allocation to the STA as needed (or at its discretion) to notify it of the link to be used. (5) The STA performs a listening operation on all links that have sent back a MU-MLO Request Response. (6) When the STA receives MU-MLO Allocation from the AP, it receives data from the AP only on the link assigned to it. (7) When the STA sends the Block ACK back to the AP, it will include RXOP information indicating whether it is still available. (8) When the AP receives a Block Ack returned from the STA, it will notify the Allocation of the retransmission of the undelivered data (optional). (9) Even without a MU-MLO Request Response, the AP may send urgent data using spare links.

[0038] Furthermore, the AP may repeatedly perform downlink MLO consisting of the operations (1) to (9) above for the duration that it has obtained TXOP. In addition, if reverse data transmission, i.e., uplink data transmission, the AP may continue to assign uplink multi-user communication parameters or assign new parameters.

[0039] B. Network Configuration Figure 1 illustrates the network configuration of a wireless LAN system to which this disclosure applies. In the example shown, multiple communication terminals (STA11~STA14) are connected to Basic Service Set 1 (BBS1), a network operated by an access point (AP10).

[0040] Furthermore, other BBSs (OBSSs) exist overlapping around BBS1. In the example shown in Figure 1, there are OBSS2 operated by AP20 and OBSS3 operated by AP30. STA21 and STA22 are connected to OBSS2, and STA31 and STA32 are connected to OBSS3.

[0041] In Figure 1, the radio wave range of each access point AP10, AP20, and AP30 is shown by dotted ellipses, which represent the range of each network.

[0042] In the network configuration shown in Figure 1, STA12 can receive signals from AP20 of BSS2, and STA13 can receive signals from AP30 of BSS3. Therefore, in BSS1, if each adjacent OBSS uses the same link, the network configuration is such that they interfere with or interfere with each other.

[0043] In this embodiment, for example, it is assumed that multilink operation will be performed on BBS1. Furthermore, it is assumed that multilink operation will be performed even in an environment where ELMMR devices and EMLSR devices are mixed within BBS1.

[0044] Figure 2 shows an example of frequency bands and channel allocations used in a wireless LAN system to which this disclosure applies. The figure shows example channel allocations in the 2.4GHz, 5GHz, and 6GHz frequency bands, which are available for use in wireless LANs. In each frequency band, the horizontal axis represents the frequency axis.

[0045] In the 2.4GHz band, when applied to a 20MHz bandwidth OFDM (Orthogonal Frequency Division Multiplexing) wireless signal according to the IEEE 802.11g standard, at least two channels of frequency are set.

[0046] Furthermore, in the 5GHz band, multiple channels can be reserved for OFDM wireless signals with a 20MHz bandwidth, due to standards such as IEEE 802.11a. However, operation in the 5GHz band is subject to the laws and regulations of each country, which dictate the usable frequency range, transmission power, and conditions for determining whether transmission is permitted. In the 5GHz band, channel numbers are assigned along the horizontal axis. In Japan, eight channels from channel 36 to channel 64 and eleven channels from channel 100 to channel 140 are available. In other countries and regions, channels 32, 68, 96, and 144 are also available, and in the higher frequency bands, channels 149 to 173 are available.

[0047] Furthermore, standardization is currently underway to enable the use of the 6GHz band as well. According to the specifications, it will be possible to deploy 25 channels in the 6GHz band A UNii-5 band, 5 channels in the 6GHz band B UNii-6 band, 17 channels in the 6GHz band C UNii-7 band, and 12 channels in the 6GHz band D UNii-8 band.

[0048] In multilink operation as defined herein, a single link is composed of one or more combinations of channels in the channel configuration shown in Figure 2. Furthermore, a single link may be composed of two or more consecutive channels on the frequency axis, or of two or more non-consecutive channels on the frequency axis.

[0049] Downlink multi-user multiplex communication applied to C.MLO Figure 3 shows an example of applying Downlink Multi-User Multiplexing (DL MU) to MLO. In Figure 3, the data transmission and reception status from the AP's perspective is shown for each link from Link 1 to Link 4, starting from the top row, when downlink multi-user multiplexing is performed. However, the horizontal axis represents the time axis, showing the data transmission and reception status for Links 1 to 4. On each time axis, an upward convex state represents the AP performing a transmission operation on the corresponding link, and a downward convex state represents the AP performing a reception operation on the corresponding link.

[0050] The AP sends a Trigger Request (TR) to each STA where the destination data resides, using all available links. The AP sends TRs using links 1 through 4 when all links are available and a TXOP has been obtained, but it may also send TRs only on the links that become available at that time.

[0051] Meanwhile, each receiving STA receives TRs from APs on all available links. If the link on which the TR was received is available, the STA sends back a Request Response (RR). The AP then receives RRs from STAs on each link.

[0052] In this case, the STA does not send back an RR on links where it is detecting signals from an adjacent OBSS or where it is setting up NAV for the OBSS, in order to avoid interfering with OBSS communication. In other words, the receiving STA sends an RR that includes information indicating that RXOP is available on that link.

[0053] Furthermore, if an STA is an EMLMR device, it may be configured to send RRs on all available links. On the other hand, if an STA is an EMLSR device, it may be configured to send RRs only on the links on which it performs the receiving operation. In other words, resources for sending RRs are allocated to STAs that are requested to send them. For example, multiple STAs may send RRs using an uplink multi-user multiplexing mechanism.

[0054] The AP can determine the available links for multi-user multiplexing communication for each STA based on the reception status of the RRs sent back from each STA. The AP then sends an Allocation (AL) to each STA to notify them in advance of the link to be used for downlink multiplexing communication. Alternatively, the AP may send subsequent downlink multi-user multiplexing data using the link that the STA has notified as available in the RR, without sending an AL.

[0055] Here, when the STA receives an AL from the AP, it receives data on the designated link based on that information. Alternatively, even if the STA does not receive an AL from the AP, it may still perform reception on the link in question to receive data from subsequent multi-user multiplexed communication.

[0056] In the example shown in Figure 3, the AP transmits Downlink User Data 1 and Downlink User Data 2 via DL MU on link 1, Downlink User Data 3 and Downlink User Data 4 via DL MU on link 2, Downlink User Data 5 and Downlink User Data 6 via DL MU on link 3, and Downlink User Data 7 and Downlink User Data 8 via DL MU on link 4.

[0057] In this way, the AP can transmit data to each STA via downlink multi-user multiplex communication.

[0058] Furthermore, each STA that receives data via downlink multi-user multiplexing is configured to send back a Block ACK (BA) as needed. In this case, the AP may pre-specify resources for sending back BAs using, for example, the uplink multi-user multiplexing mechanism, and the STA may use those resources to send back the BA. Alternatively, the STA may send back a BA that includes RXOP information indicating that reception can continue on that link.

[0059] Depending on the reception status of the BA from the STA, the AP may retransmit the data via subsequent downlink multi-user multiplexing if retransmission is necessary.

[0060] Furthermore, if there is remaining time in the TXOP on each link, the AP may send the AL again to each STA, or it may not send this AL. The AP then continues downlink multi-user communication on each link. Additionally, after the downlink multi-user communication is completed, each STA may send a BA back.

[0061] In the example shown in Figure 3, the AP sends the AL again to each STA, then sends Downlink User Data 9 and Downlink User Data 10 via DL MU on Link 1, Downlink User Data 11 and Downlink User Data 12 via DL MU on Link 2, Downlink User Data 13 and Downlink User Data 14 via DL MU on Link 3, and Downlink User Data 15 and Downlink User Data 16 via DL MU on Link 4. Then, each STA sends back the BA.

[0062] Figure 3 shows an example where this series of operations is performed simultaneously on each link, but it may also be performed asynchronously on each link.

[0063] Figure 4 shows a modified example of applying Downlink Multi-User Multiplexing (DL MU) to MLO. In Figure 4, when the AP performs downlink multi-user multiplexing, the STA sends a Clear To Send: CTS (CS) message back to ensure successful communication. In this case, the data transmission and reception status is shown from the perspective of each device (STA) of the EMLSR and ELMMR, which are the data transmission destinations. The horizontal axis is the time axis, and on this time axis, an upward convex state represents the state in which the STAs of the EMLSR and ELMMR are performing transmission operations on link N, while a downward convex state represents the state in which the STAs of the EMLSR and ELMMR are performing reception operations on link N.

[0064] The EMLSR STA is configured to send a Clear to Send: CTS (CS) instead of an RR when it receives a TR signal from an AP, in order to clearly indicate that it is operating on that link. In this case, by clearly sending back a CS, the EMLSR STA can notify devices on the overlapping network (OBSS) that it is setting up a NAV. Furthermore, if retransmission is necessary, for example, the EMLSR STA can indicate its intention to continue using the link by sending a frame equivalent to the CS along with the BA return.

[0065] In the example shown in Figure 4, the EMLSR STA receives Downlink Multi-User Data A from the AP on link N specified by the AL from the AP, then sends back BA and CS, and subsequently receives Downlink Multi-User Data B from the AP and sends back BA. This demonstrates that even when the AP is operating in multilink operation, an effective method for implementing multi-user multiplex communication is obtained, even for EMLSR STA with limited available links.

[0066] Similarly, when an ELMMR STA receives a TR signal from an AP, it sends a CS instead of an RR to clearly indicate that it is operating on that link. In this case, since an ELMMR STA can configure RXOP on other links as well, resources are not necessarily allocated to the link on which the CS was sent. If an AL indicating multi-user multiplexed communication on that link is not received from the AP, or if the AL does not include its own communication, the ELMMR STA may send a Contention Free End (CF-End) (CE) to indicate that reception has ended.

[0067] Furthermore, if an AL (Access Request) for multi-user multiplexed communication is not received on the link from the EMLSR STA to the CS (Communication Station), or if the AL does not include its own communication, the EMLSR STA may also send a CE frame equivalent to a CF-End indicating that reception has ended.

[0068] Figure 5 shows another modification of applying Downlink Multi-User Multiplexing (DL MU) to MLO. Figure 5 shows the data transmission and reception status from the STA's perspective after the STA receives the TR signal from AP on link N. The horizontal axis is the time axis, and on this time axis, an upward convex state represents the state in which the STA is performing a transmission operation on link N, and a downward convex state represents the state in which the STA is performing a reception operation on link N.

[0069] The STA sends a Clear to Send: CTS(CS) on the link where it received the TR from the AP, similar to the example shown in Figure 4 above. In the example shown in Figure 5, the STA sends a BA on link N, which is specified by the AL from the AP, following the receipt of Downlink Multi-User Data A from the AP.

[0070] Any STA, with any link, TRAfter receiving the signal, sending a CS (Critical Sentence) can notify the OBSS device to configure NAV (Network Address Venture). This ensures that the STA can reliably receive downlink multi-user multiplexed communication, even if it is not an EMLSR STA.

[0071] Figure 6 shows a modified example in which uplink multi-user multiplexing (UL MU) is performed after downlink multi-user multiplexing (DL MU) with MLO applied. Figure 6 shows the data transmission and reception status from the AP's perspective after the AP transmits the TR signal on link N. The horizontal axis is the time axis, and on this time axis, an upward convex state represents the AP performing a transmission operation on link N, and a downward convex state represents the AP performing a reception operation on link N.

[0072] The AP receives a return RR from the STA on the link to which it sent the TR. Then, depending on the reception status of the RRs returned by each STA, the AP can send an AL and then transmit data to each STA via downlink multi-user multiplexed communication (same as above). In the example shown in Figure 6, the AP performs Downlink User Data A and Downlink User Data B as downlink multi-user multiplexed communication to the STA on link N. The STA that receives the data from the AP sends a return BA.

[0073] Subsequently, the AP allocates resources for uplink multi-user multiplexed communication on link N and transmits AL on link N. Then, on link N, Uplink User Data C and Uplink User Data D are transmitted from STA to AP as uplink multi-user multiplexed communication (UL MU), and the AP receives these uplink multi-user multiplexed transmitted data. The AP may also send a BA back to the originating STA after the uplink multi-user multiplexed communication.

[0074] D.AP and STA Multilink Usage Detection Status Figure 7 shows an example of the multilink usage detection status at AP10 of the wireless LAN system shown in Figure 1. In the example shown in Figure 7, when AP10 is attempting to perform MLO using links 1 to 4, only link 2 is unable to use because it detects signals from other networks and is in a busy state.

[0075] Figure 8 shows an example of the multilink usage detection status in STA11 under AP10. In the example shown in Figure 8, STA11 is attempting to perform MLO using links 1 to 4, but has not detected any signals from other networks, and all links are available for use.

[0076] Figure 9 shows an example of the multilink usage detection status in STA12 under AP10. In the example shown in Figure 9, when STA12 is attempting to perform MLO using links 1 to 4, it intermittently detects signals from other networks on link 1, making it unavailable and resulting in a Busy state.

[0077] Figure 10 shows an example of the multilink usage detection status in STA13 under AP10. In the example shown in Figure 10, when STA13 attempts to perform MLO using links 1 to 4, it detects signals from other networks on links 3 and 4, rendering them unavailable and resulting in a Busy state. Specifically, STA13 first detects signals from other networks on link 3 and becomes Busy, and then subsequently detects signals from other networks on link 4 and becomes Busy as well.

[0078] Figure 11 shows an example of the multilink usage detection status in STA14 under AP10. In the example shown in Figure 11, STA14 is operating as an EMLSR device and is in a state where it is setting the data RXOP using only link 1 out of links 1 to 4.

[0079] As shown in Figures 7 to 11, it is conceivable that the AP and each STA under it may have different available links; in other words, it may be difficult to perform multilink operations using all links. Furthermore, it is conceivable that some of the STAs under the AP may include EMLSR devices.

[0080] E. An example of applying downlink multi-user communication to multilink. Figure 12 shows an example of applying downlink multi-user communication to a multilink in AP10 of the wireless LAN system shown in Figure 1. Here, the operation of AP10 is shown assuming that downlink multi-user communication as shown in Figure 3 is applied under the multilink usage detection conditions shown in Figure 7. However, the horizontal axis is the time axis and shows the data transmission and reception status of links 1 to 4. On each time axis, an upward convex state represents the state in which AP10 is performing a transmission operation on the corresponding link, and a downward convex state represents the state in which AP10 is performing a reception operation on the corresponding link.

[0081] AP10 is in a busy state on Link 2 due to detecting a signal from OBSS, and therefore cannot perform DL MU communication. Therefore, AP10 sends a TR to STA11-STA14, where the data to be delivered resides, on Links 1, 3, and 4, initiating the DL MU communication process.

[0082] Meanwhile, STA11-STA14, which are the receiving end, receive TRs from AP10 via links 1, 3, and 4. STA11-STA14 then send RRs containing the RXOP information at that time back to AP10 via links 1, 3, and 4.

[0083] AP10 can determine which multi-user multiplexed communication links are available to each of STA11-STA14 based on the reception status of the RRs sent back from STA11-STA14. AP10 then sends ALs to STA11-STA14 on links 1, 3, and 4 to notify them in advance of which links will be used for DL ​​MU communication.

[0084] Next, AP10 performs DL MU communication to STA11-STA14 on Link 1, Link 3, and Link 4, respectively, based on the AL. Specifically, AP10 sends Downlink User Data 1 and Downlink User Data 2 on Link 1, Downlink User Data 5 and Downlink User Data 6 on Link 3, and Downlink User Data 7 and Downlink User Data 8 on Link 4.

[0085] Subsequently, AP10 may pre-allocate resources for returning BAs from STA11-STA14 using uplink multi-user multiplexing technology. STA11-STA14 may then use these resources to return the BAs. AP10 can then determine whether there is any undelivered data that needs to be retransmitted based on the reception status of the BAs from STA11-STA14.

[0086] AP10 can resend AL to STA11-STA14 if there is remaining time in TXOP on each of links 1, 3, and 4. In the example shown in Figure 12, AP10 performs DL MU communication to STA11-STA14 on each of links 1, 3, and 4 based on AL. Specifically, AP10 sends Downlink User Data 9 and Downlink User Data 10 on link 1, Downlink User Data 13 and Downlink User Data 14 on link 3, and Downlink User Data 15 and Downlink User Data 16 on link 4. In the example shown in Figure 12, data transmission is performed on all available links, but depending on the amount of data, data transmission may be performed using only some links.

[0087] Similarly, AP10 may pre-allocate resources for returning BAs from STA11-STA14 using uplink multi-user multiplexing technology. STA11-STA14 may then use these resources to return the BAs. AP10 can determine whether there is any undelivered data that needs to be retransmitted based on the reception status of the BAs from STA11-STA14.

[0088] Figure 13 shows an example of applying downlink multi-user communication to a multilink in STA11 under AP10. Here, the operation of STA11 is shown assuming that downlink multi-user communication as shown in Figure 3 is applied under the multilink usage detection conditions shown in Figure 8. However, the horizontal axis is the time axis and shows the data transmission and reception status of links 1 to 4. On each time axis, an upward convex state indicates that STA11 is performing a transmission operation on the corresponding link, and a downward convex state indicates that SAT11 is performing a reception operation on the corresponding link.

[0089] Since STA11 has not detected any signals from OBSS on links 1 through 4, it receives a TR from AP10 on links 1, 3, and 4, and initiates the series of operations for DL ​​MU communication.

[0090] Then, STA11 sends an RR containing the RXOP information at that time back to AP10 via links 1, 3, and 4. Since DL MU communication may occur on links 1, 3, and 4 from which the RR was sent, STA11 waits for data from AP10 on all of these links.

[0091] Subsequently, STA11 receives AL from AP10 on links 1, 3, and 4. In the example shown in Figure 13, since STA11 is allocated DL MU communication resources on the AL on link 3, STA11 receives DL MU communication data addressed to itself (Downlink User Data 6) on link 3.

[0092] Next, STA11 sends a BA (Block Arbitration) to AP10 describing the data reception status. STA11 sends the BA via link 3, where the data was received, but it may also send the BA via other links as needed. In the example shown in Figure 13, STA11 sends the BA via link 1, link 3, and link 4.

[0093] If AP10 has remaining time on TXOP for each of Link 1, Link 3, and Link 4, DL MU communication may occur thereafter. For this reason, STA11 may be configured to wait for data on each of Link 1, Link 3, and Link 4.

[0094] Then, if STA11 receives an AL from AP10 again on any of Link 1, Link 3, or Link 4, it checks the contents of that AL and waits for data. In the example shown in Figure 13, since STA11 is allocated DL MU communication resources on Links 3 and 4, STA11 receives DL MU communication data addressed to itself on Links 3 and 4 (Downlink User Data 14, Downlink User Data 16).

[0095] Then, STA11 sends back a BA (Block Arbitration) to AP10 on each link, describing the data reception status on links 3 and 4.

[0096] Figure 14 shows an example of applying downlink multi-user communication to a multilink in STA12 under AP10. Here, the operation is assumed to be when STA12 applies downlink multi-user communication as shown in Figure 3, under the multilink usage detection conditions shown in Figure 9. However, the horizontal axis is the time axis, showing the data transmission and reception status of links 1 to 4. On each time axis, an upward convex state represents the state in which STA12 is performing a transmission operation on the corresponding link, and a downward convex state represents the state in which STA12 is performing a reception operation on the corresponding link.

[0097] Since STA12 detects a signal from OBSS on link 1, it receives a TR from AP10 on links 3 and 4 and initiates the DL MU communication process. Then, STA12 sends an RR containing the RXOP information at that time back to AP10 on links 3 and 4. As DL MU communication may occur on links 3 and 4 after the RR is sent back, STA12 waits for data from AP10 on these links.

[0098] Subsequently, STA12 receives AL from AP10 on links 3 and 4. In the example shown in Figure 14, STA12 is allocated DL MU communication resources on links 3 and 4, so STA12 receives DL MU communication data addressed to itself on link 3 (Downlink User Data 5) and DL MU communication data addressed to itself on link 4 (Downlink User Data 8).

[0099] Next, STA12 sends a BA (Block Action) to AP10 describing the data reception status. STA12 sends the BA via links 3 and 4, where the data was received, but may also send the BA via other links if necessary.

[0100] If AP10 has remaining time on TXOP for both Link 3 and Link 4, DL MU communication may occur thereafter. For this reason, STA12 may be configured to wait for data on both Link 3 and Link 4.

[0101] Then, if STA12 receives an AL from AP10 again on either link 3 or link 4, it checks the contents of that AL and waits for data. In the example shown in Figure 14, since STA12 is allocated DL MU communication resources by the ALs on link 3 and link 4, STA12 receives DL MU communication data addressed to itself on link 3 and link 4, respectively (Downlink User Data 13, Downlink User Data 15).

[0102] Then, STA12 sends back a BA (Block Arbitration) to AP10 for each link, describing the data reception status on links 3 and 4.

[0103] Figure 15 shows an example of applying downlink multi-user communication to a multilink in STA13 under AP10. Here, the operation is assumed to be when STA13 applies downlink multi-user communication as shown in Figure 3, under the multilink usage detection conditions shown in Figure 10. However, the horizontal axis is the time axis, showing the data transmission and reception status of links 1 to 4. On each time axis, an upward convex state indicates that STA13 is performing a transmission operation on the corresponding link, and a downward convex state indicates that STA13 is performing a reception operation on the corresponding link.

[0104] Since STA13 detects a signal from OBSS on link 3, it receives a TR from AP10 on links 1 and 4 and initiates a series of DL MU communication operations. Then, STA13 sends an RR containing the RXOP information at that time back to AP10 on links 1 and 4. Since DL MU communication may occur on links 1 and 4 after the RR is sent back, STA13 waits for data from AP10 on these links.

[0105] Subsequently, STA13 receives AL from AP10 on Link 1 and Link 4. In the example shown in Figure 15, STA13 is allocated DL MU communication resources on Link 1 and Link 4. Therefore, STA13 receives DL MU communication data addressed to itself on Link 1 (Downlink User Data 2) and DL MU communication data addressed to itself on Link 4 (Downlink User Data 7).

[0106] However, while STA13 is receiving Downlink User Data 7 on Link 4, it detects a signal from OBSS, causing some data to be missed. Therefore, STA13 includes a BA (Block Arrow) describing the data reception status on Links 1 and 4 in the BA sent back on Link 1, and sends it back to AP10.

[0107] If AP10 has remaining time on TXOP for both Link 1 and Link 4, it may subsequently attempt to retransmit the undelivered data as DL MU communication. Therefore, STA13 will wait for data on all links.

[0108] At this time, STA13 can only receive AL from AP10 on link 1 because it has detected signals from OBSS on links 3 and 4. Then, when STA13 confirms that it has been allocated resources addressed to it by receiving AL again from AP10 on link 1, it receives the undelivered data of the retransmitted Downlink User Data 7 as DL MU communication data (Downlink User Data 10) addressed to it on link 1.

[0109] Then, STA13 sends a BA (Block Arbitration) describing the data reception status on link 1 back to AP10 via link 1.

[0110] Figure 16 shows an example of applying downlink multi-user communication to the multilink of an EMLSR device. Here, similar to the example shown in Figure 11, STA14 under AP10 is operating as an EMLSR device, and is in a state where it is setting the RXOP for data using only Link 1 of Links 1 to 4, and the figure shows the operation assuming that downlink multi-user communication as shown in Figure 3 is applied. In this figure, the horizontal axis is the time axis and the data transmission state of Link 1 is shown, with an upward convex state representing the state in which STA14 is performing a transmission operation on Link 1, and a downward convex state representing the state in which STA14 is performing a reception operation on Link 1.

[0111] When STA14 receives a TR from AP10 on link 1, it sends an RR containing the RXOP information at that time back to AP10 on link 1. Since DL MU communication may take place on link 1 after the RR is sent back, STA14 waits for data from AP10 on link 1.

[0112] Subsequently, STA14 receives AL from AP10 on link 1. In the example shown in Figure 16, STA14 is allocated DL MU communication resources on link 1's AL. Therefore, STA14 receives DL MU communication data addressed to itself on link 1 (Downlink User Data 1). Then, STA14 sends a BA describing the data reception status back to AP10 on link 1.

[0113] Furthermore, if AP10 has remaining time on TXOP on link 1, DL MU communication may occur thereafter. For this reason, STA14 will wait for data on link 1.

[0114] When STA14 confirms that it has been assigned a source addressed to itself in the AL received again from AP10 on Link 1, it receives the DL MU communication data (Downlink User Data 9) addressed to itself on Link 1.

[0115] Then, STA14 sends a BA (Block Arbitration) describing the data reception status on link 1 back to AP10 via link 1.

[0116] F. Sequence of downlink multi-user multiplexing communications for each link Section F describes the sequence of downlink multi-user multiplexed communication for each link, assuming the usage detection status of each link as shown in Figures 7 to 11, in AP10 of the wireless LAN system shown in Figure 1.

[0117] Figure 17 shows the sequence of downlink multi-user multiplex communication on Link 1. In the illustrated sequence, control information and user data are exchanged between AP10 and the STA11-STA14 under its control.

[0118] First, AP10 sends a TR (DL MU MLO Trigger Request) to the subordinate STA11-STA14, which triggers the start of MLO with DL MU communication applied.

[0119] Next, STA11, STA13, and STA14, having received the TR from AP10, send back an RR (DL MU MLO Request Response) containing RXOP information to AP10.

[0120] Here, AP10 allocates DL MU communication resources based on the RXOP information of STA11, STA13, and STA14, and if necessary, sends AL (DL MU MLO Resource Allocation) to STA13 and STA14, which are multiplexed on link 1.

[0121] Then, AP10 transmits multiplexed data (DL User Data) to STA13 and STA14 respectively via Link 1. As shown in Figures 15 and 16, Downlink User Data 2 is transmitted to STA13 and Downlink User Data 1 is transmitted to STA14.

[0122] When STA13 and STA14 receive this multiplexed data (DL User Data), they each send a BA (DL MLO Block Ack) describing the reception status to AP10 via Link 1.

[0123] Figure 18 shows the sequence of downlink multi-user multiplex communication on Link 4. In the illustrated sequence, control information and user data are exchanged between AP10 and the STA11-STA14 under its control.

[0124] First, AP10 sends a TR (DL MU MLO Trigger Request) to the subordinate STA11-STA14, which triggers the start of MLO with DL MU communication applied.

[0125] Next, STA11~STA13, having received the TR from AP10, send back an RR (DL MU MLO Request Response) containing RXOP information to AP10.

[0126] Here, AP10 allocates DL MU communication resources to STA12 and STA13 based on the information of each RXOP of STA11 to STA13, and if necessary, sends AL (DL MU MLO Resource Allocation) to STA12 and STA13 which are multiplexed on link 4.

[0127] Then, AP10 transmits the multiplexed data (DL User Data) to STA12 and STA13 respectively via Link 4.

[0128] When STA12 and STA13 receive this multiplexed data (DL User Data), they send a BA (Brief Account) describing the reception status back to AP10 via link 4. As shown in Figures 14 and 15, Downlink User Data 8 is sent to STA12 and Downlink User Data 7 is sent to STA13. However, while STA13 is receiving Downlink User Data 7, it detects a signal from OBSS, causing some data to be lost. Therefore, STA13 includes a BA describing the data reception status on links 1 and 4 in the BA sent back via link 1 and sends it back to AP10.

[0129] STA12 and STA13 each send a BA (DL MLO Block Ack) via link 4 to AP10, which describes the reception status of the multiplexed data (DL User Data). At this time, STA13 will indicate in the BA that some of the data was not delivered.

[0130] G. Configuration of wireless communication equipment Figure 19 schematically shows the functional configuration of a wireless communication device 1900 to which this disclosure applies. The illustrated wireless communication device 1900 can operate as an access point (AP) in, for example, the wireless LAN system shown in Figure 1. Of course, the wireless communication device 1900 may also operate as a communication terminal (STA) under any access point.

[0131] The illustrated communication device 1900 comprises the following functional modules: a network connection module 1901, an information input module 1902, an equipment control module 1903, an information output module 1904, and a wireless communication module 1905. The communication device 1900 may further comprise other functional modules not shown, but these are not essential for realizing this disclosure and are therefore omitted from the illustration.

[0132] The network connection module 1901 is configured to implement functions such as a communication modem for connecting to a wide-area communication network such as the Internet, for example, when the wireless communication device 1900 operates as an access point. For example, the network connection module 1901 establishes an Internet connection via a public communication line and an Internet service provider.

[0133] The information input module 1902 is a module that inputs information conveying instructions from the user, and consists of, for example, push buttons, a keyboard, a touch panel, a mouse, or other input devices.

[0134] The device control module 1903 is the part that controls the communication device intended by the user to operate as an access point.

[0135] The information output module 1904 is the part that specifically displays the operating status of the wireless communication device 1900 and information obtained via the network. It consists of display elements such as an LED (Light Emitting Diode) display, a liquid crystal panel, or an organic EL (Electro-Luminescence) display, as well as a speaker that outputs sound or music, and can display or notify the user of the necessary information as needed.

[0136] The wireless communication module 1905 is a functional module for processing wireless communication. This disclosure is essentially realized by the functions provided by the wireless communication module 1905.

[0137] Figure 20 shows in detail the internal configuration of the wireless communication module 1905, which is one of the functional modules included in the wireless communication device 1900 shown in Figure 19. The illustrated wireless communication module 1905 comprises an interface 2001, a transmit buffer 2002, a transmit sequence management unit 2003, a transmit frame construction unit 2004, a network management unit 2005, a multilink management unit 2006, a multiuser multiplexing processing unit 2007, a multilink access control unit 2008, a transmit unit 2009, an antenna control unit 2010, an antenna unit 2011, a detection unit 2012, a receive unit 2013, a receive frame analysis unit 2014, a receive sequence management unit 2015, and a receive buffer 2016.

[0138] Interface 2001 is connected to other modules within the wireless communication device 1900 (such as the equipment control module 1903) to exchange various types of information and data.

[0139] The transmit buffer 2002 temporarily stores data to be transmitted wirelessly, for example, data received from other modules.

[0140] The transmission sequence management unit 2003 understands the data to be transmitted for each destination and manages the transmission sequence. The transmission frame construction unit 2004 constructs a transmission frame for each destination.

[0141] The Network Management Unit 2005 manages information on access points and communication terminals belonging to its own network (BSS). The Multilink Management Unit 2006 manages the operation of the MLO.

[0142] The multi-user multiplexing processing unit 2007 performs processing for multi-user multiplex communication.

[0143] The multilink access control unit 2008 controls transmission and reception on each link of the multilink based on a predetermined access control procedure.

[0144] The transmitter 2009 processes the transmission of the data to be transmitted. The transmitter 2009 includes multiple transmitters A to D (corresponding to the number of multilinks) to process the transmission of each link of the multilink and the user-multiplexed data individually. Although four transmitters A to D are shown in Figure 20 for convenience, the number of transmitters may be three or fewer, or five or more. However, if the wireless communication device 1900 is an EMLSR device, the transmitter 2009 may consist of only one transmitter.

[0145] The antenna control unit 2010 controls the antenna unit 2011, which transmits and receives wireless signals. The antenna unit 2011 is equipped with antenna elements that actually perform the transmit and receive operations. The antenna unit 2011 is provided with a number of antennas A to D corresponding to the number of multilinks as needed, but it may be three or fewer or five or more.

[0146] The detection unit 2012 detects the signal received by the antenna unit 2011. The detection unit 2012 includes multiple detection units A to D (corresponding to the number of multilinks). Although four detection units A to D are shown in Figure 20 for convenience, the number of detection units may be three or fewer, or five or more. However, even if the wireless communication device 1900 is an EMLSR device, a detection unit equal to the number of links is provided.

[0147] The receiver unit 2013 processes the data received via the antenna unit 2011 and the detection unit 2012. The receiver unit 2013 includes multiple receiver units A to D (corresponding to the number of multilinks) to process the data from each link of the multilink and the user-multiplexed data. Although four receiver units A to D are shown in Figure 20 for convenience, the number of receiver units may be three or fewer, or five or more. However, if the wireless communication device 1900 is an EMLSR device, the transmitter unit 2009 may have only one receiver unit.

[0148] The received frame analysis unit 2014 decodes predetermined data from the signals received by each receiving unit A to D and constructs the received data. The received sequence management unit 2015 extracts the data (payload) portion from the received frame and manages the received sequence. The received buffer 2016 temporarily stores the received data.

[0149] When the wireless communication device 1900 operates as an access point, the TR and AL are instructed to transmit by the multilink management unit 2006 and constructed as their respective transmission frames by the transmission frame construction unit 2004.

[0150] Furthermore, when the wireless communication device 1900 operates as an access point, the RR and BA transmitted from the communication terminal are processed by each receiving unit A to D for each individual link and each individual user, and are processed as received frames by the received frame analysis unit 2014.

[0151] On the other hand, when the wireless communication device 1900 operates as a communication terminal and receives a TR, the received frame analysis unit 2014 recognizes the TR, the multilink management unit 2006 collects RXOP information, sets the RR to be transmitted to the access point, and the transmission frame construction unit 2004 constructs the RR frame.

[0152] Furthermore, when the wireless communication device 1900 operates as a communication terminal and receives an AL from the connected access point, the received frame analysis unit 2014 recognizes the AL, and the multilink management unit 2006 is instructed to perform reception processing using the DL MU communication resources allocated by that AL.

[0153] Furthermore, when the wireless communication device 1900 operates as a communication terminal, the receiving sequence management unit 2015 constructs a BA frame according to the reception status of data addressed to itself, and the transmitting frame construction unit 2004 constructs a BA frame from this.

[0154] H. Frame Configuration Section H describes the structure of frames used in wireless LAN systems to which this disclosure applies.

[0155] Figure 21 shows the configuration of the management frame required for MLO settings. The management frame here includes the DL Trigger Request (TR) frame, DL Request Response (RR) frame, and DL Allocation (AL) frame.

[0156] The frame shown in Figure 21 consists of the following fields as a predetermined MAC (Media Access Control) header: Frame Control, which identifies the type of frame; Duration, which indicates the duration of the frame; Receive Address, which specifies the receiving device; and Transmit Address, which specifies the sending device.

[0157] Furthermore, the frame shown in Figure 21 includes a Multi-User Multi-Link Operation (MU MLO) information element as a MAC payload, and a frame check sequence (FCS) for data error detection is added to the end of the frame.

[0158] The MU MLO information element includes a Type indicating the format of the MU MLO frame, a Length indicating the information length, and parameters required for the actual MLO operation. The configuration of this MU MLO information element differs for each management frame. Details of the configuration of this information element in each management frame will be described later.

[0159] Figure 22 shows the correspondence between the values ​​entered in the Type field of the MU MLO information element and the corresponding frame format. In this figure, 1: DL Trigger Request, 2: DL Request Response, 3: DL Allocation, 5: UL Trigger Request, 6: UL Request Response, and 7: UL Allocation are defined.

[0160] Figure 23 shows the structure of the MU MLO Information Element field in a DL Trigger Request (TR) frame.

[0161] This information element is indicated as Type=01, representing the MU MLO information element of a DL Trigger Request. This information element consists of Multi-Link Information, which indicates parameters related to multilink operation; Multi-User Information, which indicates parameters related to multi-user communication; TXOP Max. Duration, which indicates the maximum length of the downlink communication transmission opportunity; TXOP Min. Duration, which indicates the minimum required length; and other parameters that may be added as needed. Upon receiving the TR frame, the communication terminal can estimate the remaining transmission time available to the sender based on the maximum transmission time information described in TXOP Max. Duration. In addition, any other parameters may be included as needed.

[0162] The Multi-Link Information field consists of parameters such as Multi-Link Counts, which indicates the number of multilinks; Request Multi-Link Bitmap, which identifies the channels of the requested multilinks in bitmap format; and 1st Link Info~Nth Link Info, which shows information for the first to Nth links.

[0163] Furthermore, the Multi-User Information field consists of parameters such as Multi-User Type, which indicates the method of multi-user multiplexing; Number of Streams, which indicates the number of multiplexing operations per link; and Request Streams, which indicates the number of streams to request to be received simultaneously from the receiving communication terminal.

[0164] Figure 24 shows the structure of the MU MLO Information Element field in a DL Request Response (RR) frame.

[0165] This information element is indicated as Type=02, representing the MU MLO information element for DL ​​Request Response. This information element consists of Multi-Link Information, which indicates parameters related to multilink operation; Multi-User Information, which indicates parameters related to multi-user communication; RXOP Max. Duration, which indicates the maximum length of downlink communication reception opportunities; RXOP Min. Duration, which indicates the minimum required length; and other parameters that may be added as needed.

[0166] The Multi-Link Information field consists of parameters such as Multi-Link Counts, which indicates the number of multilinks; Available Multi-Link Bitmap, which identifies the available multilink channels in bitmap format; and 1st Link Info to Nth Link Info, which show information for the first to Nth links.

[0167] The Multi-User Information field also consists of parameters such as Multi-User Type, which indicates the method of multi-user multiplexing, and Available Streams, which indicates the number of available streams per link.

[0168] Furthermore, this information element includes other parameters such as EMLSR / EMLMR, which identifies whether the communication terminal is an EMLSR or an ELMMR.

[0169] Figure 25 shows the structure of the MU MLO Information Element field in the DL Allocation (AL) frame.

[0170] This information element is indicated as Type=03, which means it is a DL Allocation MU MLO information element. This information element consists of Multi-Link Information, which indicates parameters related to multilink operation; Multi-User Information, which indicates parameters related to multi-user communication; Current TXOP Duration, which indicates the opportunity to send downlink communication in this Allocation frame; Total TXOP Duration, which indicates the opportunity to send transmission if continued use is required; and other parameters that may be added as needed, such as ACK Policy, which indicates how to return the ACK; and After Allocation, which indicates the subsequent resource allocation. The ACK Policy parameter can be used to notify the allocation of resources to receive block ACKs from the receiving side.

[0171] The Multi-Link Information field consists of parameters such as Multi-Link Counts, which indicates the number of multilinks; Allocate Multi-Link Bitmap, which identifies the allocated multilink channels in bitmap format; and Multi-Link Allocation, which corresponds to parameters such as the bandwidth of the link from which the Allocation frame was sent.

[0172] Furthermore, the Multi-User Information field consists of parameters such as Multi-User Allocation, which indicates the method of multi-user multiplexing; Number of Streams, which indicates the number of multiplexing attempts per link; and 1st Used Info to Mth User Info, which show user information from the 1st to the Mth. Each user's information consists of parameters such as Resource, which indicates the allocated resource, and Device, which identifies the device.

[0173] Figure 26 shows the structure of a downlink Block Acknowledgement (BA) frame. The BA frame has a structure that contains information equivalent to that of a conventional BA frame, and includes a predetermined MAC header (same as above), followed by the BA Control and BA Information fields, with an FCS for error detection added at the end.

[0174] The BA Control field consists of the following parameters: BA Ack Policy, BA Type, MLO Control, and TID_INFO. BA Type indicates the format of the BA frame. Figure 26 shows the correspondence between the values ​​entered in the BA Type field and the corresponding BA frame formats. In this embodiment, 12:MU MLO is defined as a new BA Type.

[0175] Furthermore, in this embodiment, the bit portion of the BA Control field that was conventionally set to Reserved contains MLO Control parameters as needed. This MLO Control consists of parameters such as More Data, which indicates that more data is needed; TXOP / RXOP, which identifies whether TXOP or RXOP can be configured; Multi-Link Counts, which indicates the number of links that can operate in multi-link mode; and Available Link Bitmap, which shows the available links in bitmap format.

[0176] I. Example of Downlink Communication Operation Section I describes the operations performed by access points and communication terminals during downlink communication in a wireless LAN system to which this disclosure applies.

[0177] Figures 27 and 28 show the operations performed by the access point during downlink communication in flowchart form. Here, the downlink multi-user multiplexing communication described herein is shown as part of the MLO, and the operation sequence initiated by the access point sending a trigger is shown in flowchart form.

[0178] First, when the access point receives transmission data from the upper layer of the communication protocol (Yes in step S2701), it stores that data in the transmission buffer 2002 (step S2702) and obtains the address of the receiving communication device (step S2703).

[0179] Then, if the access point is to perform downlink multi-user communication over multiple links (Yes in step S2704), it sets the multi-user and multi-link parameters (step S2705) and performs access control on each link that operates as a multi-link (step S2706).

[0180] If there is a link that can transmit data (Yes in step S2707), the access point sends a Trigger Request (TR) frame on that link (step S2708). If the access point is able to receive a Request Response (RR) frame from a Communication Terminal (STA) on that link (Yes in step S2709), the access point sequentially stores the responding STA and response parameters along with the corresponding link information (step S2710).

[0181] Then, returning to step S2707, the access point performs the transmission of this TR frame on all transmittable links.

[0182] Subsequently, once the reception of RR frames is complete on all transmittable links (No in step S2707), the access point obtains information from the responding STAs on each link (step S2711). If the responding STA is a device with significant constraints on available links or resources, such as an EMLSR device (Yes in step S2712), the access point prioritizes allocating the response link to that device (step S2714). If the response is from an STA that does not have significant constraints on available links or resources, such as an EMLSR device (No in step S2712), but has undelivered data (Yes in step S2713), the access point prioritizes allocating the response link to that device (step S2714). For any other responses from STAs, the access point allocates the remaining resources as appropriate (step S2715). In steps S2714 and S2715, the access point sets parameters related to multilink operation based on the allocated resources, as well as parameters related to multiuser communication.

[0183] Once the access point has completed resource allocation for all STAs that have responded to the TR frame (Yes in step S2716), if there are any resources remaining (Yes in step S2717), it may, if necessary, duplicate resources for data requiring highly reliable communication (step S2718).

[0184] The access point then generates an AL frame containing the parameters related to multilink operation and multiuser communication set in step S2714 or S2715, and transmits the AL frame on an available link (step S2719). Subsequently, the access point retrieves the data stored in the transmit buffer 2002 in step S2702 (step S2720), and performs downlink multiuser communication on each link according to the resource allocation described above (step S2721).

[0185] Subsequently, the access point receives BA frames from each receiving STA using the resources allocated by the ACK Policy parameter of the AL frame (step S2722). Then, the access point checks for any undelivered data based on the acknowledgment status of the BA frames received from each STA (step S2723).

[0186] If there is no undelivered data (Yes in step S2723), the access point terminates this process.

[0187] On the other hand, if there is any undelivered data (No. in step S2723), the access point checks if there is any remaining time for TXOP (S2724).

[0188] If there is remaining time in TXOP (Yes in S2724), the access point can return to step S2705 and perform downlink multi-user multiplex communication again on each link if it needs to continue. If there is no remaining time in TXOP (No in step S2724), the access point terminates this process.

[0189] Figures 29 and 30 show the operations performed by a communication terminal during downlink communication in flowchart form. Here, the downlink multi-user multiplexing communication described in this disclosure is shown as part of MLO, and the operation sequence initiated when the communication terminal receives a trigger from the access point is shown in flowchart form.

[0190] First, the communication terminal performs a receive operation on the operating link of the multilink operation (step S2901). Even if the communication terminal is a device with significant constraints on the available links or resources, such as an EMLSR device, it may be configured to perform the detection operation of a predetermined preamble signal on a multilink.

[0191] Here, if the communication terminal receives a signal destined for OBSS or other communication devices (Yes in step S2902), it sets the link to enter a BUSY state (step S2903). Alternatively, in step S2903, if the communication terminal receives an RTS (Request To Send) or CTS (Clear To Send) frame, it may set a network allocation vector (NAV) for virtual carrier sensing according to the Duration time information contained therein.

[0192] On the other hand, if the communication terminal receives a trigger frame for downlink multi-user multiplex communication from the connected access point (Yes in step S2904), it obtains the parameters for MLO in DL MO communication from the received frame (S2905), and if RXOP can be set on the link in question (S2906), the communication terminal sets the received parameters (step S2907). However, if NAV is set on the link in question, the communication terminal does not set RXOP on that link.

[0193] Next, the communication terminal checks whether it is a device with significant limitations on available links or resources, like an EMLSR device (step S2908). If the communication terminal is a device with significant limitations on available links or resources, like an EMLSR device, and further specifies the link to be used, it may be configured to send a CTS frame to the access point as needed (step S2910). If the communication terminal is not a device with significant limitations on available links or resources, like an EMLSR device, or for any other reason, it sends an RR frame (step S2909).

[0194] The communication terminal then waits for downlink multi-user communication data on the link from which the CTS frame or RR frame was transmitted (step S2911).

[0195] Here, when the communication terminal receives an AL frame from the access point it is connected to, (step S 2912 ), and according to that setting, receive the data for subsequent downlink multi-user communications (step S 2913 ).

[0196] Next, the communication terminal checks whether it was able to successfully receive data (MAC Protocol Data Unit: MPDU) in the MLO during DL MU communication (step S2914). If the data was successfully received (Yes in step S2914), the access point stores the received data in the receive buffer 2016 (step S2915) and stores the received sequence number as ACK information (S2916). If there is an error in the received data, the received data is not stored, and its sequence number is not stored as ACK information.

[0197] Furthermore, after receiving all the data, if the communication terminal is requested to return a BA frame (Yes in S2917), it obtains the ACK information collected in the preceding step S2916 (step S2918). Then, if the communication terminal has not detected any signals from OBSS, or if there are no errors in the data, and the access point's TXOP can continue and RXOP can be configured on that link (step S2919), the communication terminal proceeds to set the request response parameters (S2920).

[0198] Then, when the communication terminal obtains, for example, the parameters of the resource for sending the BA back that is set following the DL MU communication (S2921), it sends the BA frame using the resource specified in the ACK Policy parameter of the AL frame (step S2922).

[0199] The communication terminal then terminates this process if it has finished receiving all data addressed to itself (Yes in step S2923). If it is not requested to send a BA frame back (No in S2917) or if it has not finished receiving all data addressed to itself (No in step S2923), it returns to S2902 and repeats the above operation.

[0200] Although Figures 29 and 30 describe the operation as being confined to a single link, if the communication terminal uses multiple links to receive multi-user communication, the reception process may be performed simultaneously on each link. The operation described in step S2912 is to repeat these processes each time a frame is received on each link.

[0201] J. Effect Section J summarizes the effects of this disclosure.

[0202] (1) The transmitting communication device can identify which links are available for use in multilink mode for each receiving communication device by receiving reception opportunity information (RXOP) from the receiving communication device on the link on which it obtained a transmission opportunity (TXOP).

[0203] (2) In an environment where OBSS exists, even if multilink is not available on all receiving communication devices, the transmitting communication device can perform multi-user communication using the links available on the receiving communication devices each time.

[0204] (3) The receiving communication device, which is an EMLSR, can also send RXOP information back to the transmitting communication device using the link it is currently receiving from. Therefore, the transmitting communication device can determine which link the receiving communication device, which is an EMLSR, is using to communicate.

[0205] (4) The transmitting communication device can identify the available links at that time through a communication sequence in which the transmitting communication device sends a Trigger Request frame and the receiving communication device returns a Request Response.

[0206] (5) The transmitting communication device can assign the most suitable link to each receiving communication device based on the status of receiving the Request Response sent back from the receiving communication device, and can efficiently utilize the multilinks for which transmission opportunities have been obtained.

[0207] (6) The receiving communication device can determine whether retransmission is necessary by sending back a Block ACK frame as needed. Furthermore, if the transmitting communication device can continue to use the transmission path, the receiving communication device can send back a response containing RXOP information, allowing the transmitting communication device to continue transmitting.

[0208] (7) In short, the transmitting communication device does not only transmit data to one communication terminal per link, but also uses multi-user multiplex communication technology to perform data communication using links that the communication terminal can receive. Therefore, by applying multi-user communication to MLO, the transmission path can be used efficiently. [Industrial applicability]

[0209] The present disclosure has been described in detail above with reference to specific embodiments. However, it will be obvious that those skilled in the art can modify or substitute these embodiments without departing from the gist of the present disclosure.

[0210] This disclosure is applicable, for example, to network environments where it is difficult to utilize all channels in multilink operation. Each communication terminal notifies the access point of the multilinks on which it can set up a receiving opportunity, and the access point allocates links to each communication terminal to transmit data based on the notified information, thereby realizing downlink multi-user multiplexed communication applicable to multilink operation. Furthermore, according to this disclosure, since the access point sets up a receiving opportunity for downlink multiplexed communication for each communication terminal under its control and transmits data, it is possible to effectively allocate the resources of the link on which the communication terminal is operating to the EMLSR communication terminal as well. In other words, according to this disclosure, it is possible to improve the overall throughput of the network by applying it to network environments where it is difficult to perform multilink operation using all channels.

[0211] Of course, this disclosure can also be applied to networks where multilink operation using all channels is easy, allowing access points to efficiently allocate data transmission link resources to each communication terminal according to the amount of data to be transmitted, thereby improving overall network throughput.

[0212] Furthermore, while this specification has primarily described embodiments in which the disclosure is applied to a wireless LAN system based on the IEEE 802.11 standard, the scope of application of this disclosure is not limited to a specific wireless standard, and the disclosure can be similarly applied to various types of wireless networks.

[0213] In short, this disclosure has been explained in the form of examples, and the contents of this specification should not be interpreted restrictively. The claims should be considered in order to determine the gist of this disclosure.

[0214] Furthermore, this disclosure may also take the following form.

[0215] (1) A communication unit capable of wireless communication via multiple links, A communication processing unit that performs the process of simultaneously transmitting data to multiple receiving communication devices, A control unit that performs control to transmit data using the optimal link for each of the multiple receiving communication devices, A communication device equipped with the following.

[0216] (2) The control unit controls the link on which a transmission opportunity has been acquired to send a trigger request signal to the plurality of receiving communication devices requesting information about the reception opportunity. The communication device described in (1) above.

[0217] (3) The control unit controls to receive a request response signal in response to the trigger request signal. The communication device described in (2) above.

[0218] (4) The control unit determines the optimal link for each receiving communication device based on the request response signals from the plurality of receiving communication devices. The communication device described in (3) above.

[0219] (5) The control unit prioritizes the request response signals received from receiving communication devices with significant communication resource constraints and determines the optimal link for each receiving communication device. The communication device described in (4) above.

[0220] (6) The control unit controls the transmission of an allocation signal that includes information about the link assigned to each receiving communication device and information about multi-user multiplex communication. A communication device as described in any of (1) through (5) above.

[0221] (7) The control unit controls the simultaneous transmission of data to the multiple receiving communication devices using the multiple links, based on the link information assigned to each receiving communication device and the information regarding multi-user multiplex communication. The communication device described in (4) above.

[0222] (8) The control unit controls the allocation of resources to receive block ACKs from the plurality of receiving communication devices. A communication device as described in any of (1) through (7) above.

[0223] (9) If there is remaining time for the transmission opportunity, the control unit repeatedly transmits the allocation signal. A communication device as described in either (6) or (7) above.

[0224] (10) A communication method in a communication device capable of wireless communication over multiple links, The steps include determining the optimal link for each of the plurality of receiving communication devices, The steps include: using the optimal link for each receiving communication device to simultaneously transmit data to multiple receiving communication devices; A communication method that includes [something].

[0225] (11) A communication unit capable of wireless communication via multiple links, A communication processing unit that processes data addressed to itself from among data simultaneously transmitted from a transmitting communication device to multiple receiving communication devices, A control unit that notifies the transmitting communication device of its available link reception opportunities and controls the receiving of data from the transmitting communication device on the specified link, A communication device equipped with the following.

[0226] (12) The control unit, in response to receiving a trigger request signal from the transmitting communication device, controls the device to send back a request response signal on a link where it can obtain a reception opportunity. The communication device described in (11) above.

[0227] (13) The control unit controls the system to send back a request response signal on all links where it has obtained a reception opportunity. The communication device described in (12) above.

[0228] (14) If the communication unit or the communication processing unit has significant limitations on communication resources, the control unit controls the link on which reception is performed to transmit a Clear To Send signal. A communication device as described in any of (11) to (13) above.

[0229] (15) The control unit controls the link from which the request response signal was transmitted to wait for the transmission of data from the transmitting communication device to be received by multiple receiving communication devices. A communication device as described in either (12) or (13) above.

[0230] (15-1) The control unit controls the link specified by the allocation signal received from the transmitting communication device to wait for the reception of data from the transmitting communication device to a plurality of receiving communication devices. A communication device as described in any of (12) to (14) above.

[0231] (16) The control unit controls the sending communication device to send a block ACK back. A communication device as described in any of (11) to (15) above.

[0232] (17) The control unit controls the transmission of the block ACK using the resources allocated from the transmitting communication device. The communication device described in (16) above.

[0233] (18) The control unit controls the system to perform signal waiting processing when data retransmission from the transmitting communication device is required. A communication device as described in either (16) or (17) above.

[0234] (19) If the transmitting communication device has remaining transmission time, the control unit shall return information regarding its own reception time. A communication device as described in any of (11) to (18) above.

[0235] (20) A communication method in a communication device capable of wireless communication over multiple links, The steps include notifying the transmitting communication device of information regarding the opportunity to receive links that are available to it, The steps include: receiving data addressed to oneself from among data simultaneously transmitted from the transmitting communication device to multiple receiving communication devices via a link specified by the transmitting communication device; A communication method that includes [something]. [Explanation of Symbols]

[0236] 1900... Wireless communication device, 1901... Network connection module 1902... Information input module, 1903... Equipment control module 1904…Information output module, 1905…Wireless communication module 2001…Interface, 2002…Transmit buffer 2003…Transmission Sequence Management Unit, 2004…Transmission Frame Construction Unit 2005…Network Management Department, 2006…Multilink Management Department 2007…Multi-user multiplexing processing unit 2008…Multilink access control unit, 2009…Transmitter unit 2010…Antenna control unit, 2011…Antenna unit 2012...Detection unit, 2013...Receiver unit 2014…Received Frame Analysis Unit, 2015…Received Sequence Management Unit 2016…Receive buffer

Claims

1. A communication processing unit that performs the process of simultaneously transmitting data to multiple receiving communication devices via a communication unit capable of wireless communication over multiple links with different frequency bands, A control unit that performs control to transmit data to each of the plurality of receiving communication devices, It is equipped with, The control unit identifies whether each of the plurality of receiving communication devices can communicate simultaneously on multiple links or can only transmit or receive on one link, and determines the optimal link with a different frequency band for each of the plurality of receiving communication devices. A communication device equipped with the following.

2. The control unit identifies, based on the information contained in the signals received from each of the plurality of receiving communication devices, whether the receiving communication device can communicate simultaneously on multiple links or can only transmit or receive on one link. The communication device according to claim 1.

3. The control unit, In a link where a transmission opportunity has been acquired, a trigger request signal is sent to the multiple receiving communication devices requesting information regarding the reception opportunity, and they are controlled to receive a request response signal in response to the trigger request signal. Based on the information contained in the request response signals from the multiple receiving communication devices, the receiving communication device identifies whether it can communicate simultaneously on multiple links or whether it can only transmit or receive on one link. The communication device according to claim 1.

4. The control unit preferentially assigns a link to the receiving communication device of the EMLSR. The communication device according to claim 3.

5. The control unit prioritizes assigning a link to receiving communication devices where undelivered data exists. The communication device according to claim 1.

6. The control unit controls the transmission of an allocation signal that includes information about the link assigned to each receiving communication device and information about multi-user multiplex communication. The communication device according to claim 1.

7. The control unit controls the simultaneous transmission of data to the multiple receiving communication devices using the multiple links, based on information regarding the links assigned to each receiving communication device and information regarding multi-user multiplex communication. The communication device according to claim 1.

8. The control unit controls the allocation of resources to receive block ACKs from the plurality of receiving communication devices. The communication device according to claim 1.

9. The control unit, if there is remaining time for transmission, repeatedly transmits the allocation signal. The communication device according to claim 6.

10. A communication method in a communication device capable of wireless communication over multiple links with different frequency bands, The steps include identifying whether each of the multiple receiving communication devices can communicate simultaneously on multiple links or can only transmit or receive on one link, and determining the optimal link with a different frequency band for each of the multiple receiving communication devices, The steps include: simultaneously transmitting data to multiple receiving communication devices using the optimal link with different frequency bands for each receiving communication device; A communication method that includes [something].

11. A communication processing unit that performs the process of receiving data addressed to itself from among data simultaneously transmitted from a transmitting communication device to multiple receiving communication devices via a communication unit capable of wireless communication over multiple links with different frequency bands, A control unit that sends a signal to the transmitting communication device that includes information indicating that it can communicate on multiple links simultaneously and information regarding the opportunity to receive data on the available links, and controls the receiving of data from the transmitting communication device on the designated link. A communication device equipped with the following.

12. The control unit, in response to receiving a trigger request signal from the transmitting communication device, controls the device to return a request response signal on a link where it can acquire a reception opportunity. The communication device according to claim 11.

13. The control unit controls the system to send back a request response signal on all links where it has obtained a reception opportunity. The communication device according to claim 12.

14. If the communication unit or the communication processing unit has significant limitations on communication resources, the control unit controls the link on which reception is performed to transmit a Clear To Send signal. The communication device according to claim 11.

15. The control unit controls the link from which the request response signal was transmitted to wait for the transmission of data from the transmitting communication device to be received by multiple receiving communication devices. The communication device according to claim 12.

16. The control unit controls the sending communication device to return a block ACK. The communication device according to claim 11.

17. The control unit controls the transmission of the block ACK using the resources allocated from the transmitting communication device. The communication device according to claim 16.

18. The control unit controls the system to perform signal waiting processing when data retransmission from the transmitting communication device is required. The communication device according to claim 16.

19. The control unit, if the transmitting communication device has remaining transmission time, returns information regarding its own reception time. The communication device according to claim 11.

20. A communication method in a communication device capable of wireless communication over multiple links with different frequency bands, The steps include sending a signal to the transmitting communication device that includes information indicating that it can communicate on multiple links simultaneously and information regarding the availability of links for receiving communications, The steps include: receiving data addressed to oneself from among data simultaneously transmitted from the transmitting communication device to multiple receiving communication devices via a link specified by the transmitting communication device; A communication method that includes [something].

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