Enabling the operation of legacy (non-EHT) stations in the conditional link of Soft AP MLD

Abstract

A wireless communication protocol that enables legacy (non-EHT) stations (STAs) to operate on a conditional link in soft-AP MLD. Legacy devices can connect to the conditional link to set up a link connection, and a scheduler is configured to enable use of the conditional link by the legacy STAs when no IDC interference issues exist in soft-AP MLD. The enhanced protocol utilizes either a cooperative HCCA schedule created for simultaneous transmission and reception over the basic link and the conditional link, or adaptive polling-based scheduling performed for the conditional link in response to the link status of the basic link.

Description

Technical Field

[0001] 〔Cross - Reference to Related Applications〕 This application claims priority and the benefit thereof to U.S. Patent Application Serial No. 17 / 737,255, filed on May 5, 2022, which is hereby incorporated by reference in its entirety. This application claims priority and the benefit thereof to U.S. Provisional Patent Application Serial No. 63 / 208,551, filed on June 9, 2021, which is hereby incorporated by reference in its entirety.

[0002] 〔Description of Research or Development Sponsored by the Federal Government〕 Not applicable

[0003] 〔Notice of Materials Subject to Copyright Protection〕 Some of the materials in this patent document may be subject to copyright protection under the copyright laws of the United States of America and other countries. The copyright owners do not object to the reproduction of the patent document or patent disclosure by a third party as represented in the public files or records of the United States Patent and Trademark Office, but reserve all copyrights otherwise. The copyright owners do not hereby waive any rights to keep this patent document confidential, including, but not limited to, the rights accorded under 37 C.F.R. § 1.14.

[0004] The technology of this disclosure generally relates to wireless network protocols for operation over multi - link device (MLD) stations, and specifically to enabling the use of conditional links of a soft access point MLD by legacy (non - EHT) MLD stations.

Background Art

[0005] In IEEE 802.11e, a Hybrid Coordination Function (HCF) was proposed to provide Quality-of-Service (QoS) for real-time applications. This protocol uses an Enhanced Distributed Channel Access (EDCA) mechanism for contention-based transfers and a control channel access called HCF Controlled Channel Access (HCCA) mechanism for contention-free transfers. EDCA defines multiple Access Categories (ACs) including AC-specific contention window (CW) sizes, Arbitration Interframe Space (AIFS), and Transmit Opportunity (TXOP) limits to support QoS and prioritization at the MAC level. These standards are targeted at stations with Extremely High Throughput (EHT) designed to provide Wi-Fi over the 2.4 GHz, 5 GHz, and 6 GHz frequency bands.

[0006] Under this protocol, the Soft AP MLD is designed to communicate with legacy (non-EHT) STAs only on the basic link to prevent Intra-Device Coexistence (IDC) interference, thus limiting the achievable quality of service and performance.

[0007] As a result, the capabilities of legacy (non-EHT) devices operating on these advanced networks are severely limited. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] Accordingly, there is a need for advanced means to address the Soft AP issues when enabling legacy (non-EHT) stations. The present disclosure addresses these needs and provides further advantages. MEANS FOR SOLVING THE PROBLEMS

[0009] The present disclosure is a protocol that enables a non-EHT legacy STA, which can be configured for, for example, high throughput (HT), very high throughput (VHT), or high efficiency (HE) protocols, to operate on a conditional link of a soft AP MLD. The legacy device can connect on the conditional link through active or passive scanning to establish a link connection. The scheduler is configured to enable the use of the conditional link by the legacy STA when no IDC interference problem occurs in the soft AP MLD.

[0010] In previous protocols, in order to prevent IDC interference problems on the soft AP side, the soft AP MLD protocol can only communicate with a legacy (non-EHT) STA on a basic link. As a result, the service quality and performance of the legacy STA are degraded due to the limited channel resources of the legacy STA.

[0011] In this advanced protocol, two main methods can be used to overcome these problems. In the first method, a cooperative HCCA schedule for simultaneous transmission and reception via the basic link and the conditional link is created. In the second method, adaptive polling-based scheduling is performed for the conditional link according to the state of the basic link.

[0012] In the following parts of this specification, further aspects of the technology described in this specification will become apparent, and this detailed description is for the purpose of fully disclosing the technology without limiting the preferred embodiments of the technology.

[0013] The technology described in this specification will be fully understood by referring to the following drawings for illustrative purposes only.

Brief Description of the Drawings

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Mode for Carrying Out the Invention

[0015] 1. Introduction 1.1 Hybrid Coordination Function (HCF) In IEEE802.11e, it is proposed to provide QoS for real-time applications. This proposal consists of an Extended Distributed Channel Access (EDCA) mechanism for contention-based transfer and a control channel access called the HCF Control Channel Access (HCCA) mechanism for contention-free transfer.

[0016] 1.2 HCF Control Channel Access (HCCA) HCCA starts a frame exchange sequence using a centralized coordinator called a Hybrid Coordinator (HC) aware of Quality of Service (QoS), and allocates a Transmission Opportunity (TXOP) for contention-free (CF) transmission of QoS data to the local station and other stations (STAs). The HC has a higher Medium Access (MAC) priority than non-Access Point (non-AP) STAs. The HC permits a polling type TXOP with a specified period in a QoS(+)CF-Poll frame to the STA. The STA can start a plurality of frame exchange sequences according to the limit of the TXOP period during the polling type TXOP.

[0017] When it is determined that the wireless medium (WM) is idle at the transmission (Tx) PCF Interframe Space (PIFS) slot boundary, the HC can access the wireless medium (WM) to start the Contention Access Phase (CAP). The HC shall transmit the QoS(+) CF-Poll or the first frame of any permitted frame exchange sequence together with a duration value set to cover a polling type TXOP or an HCCA TXOP respectively.

[0018] The CAP shall not extend beyond the Target Beacon Transmission Time (TBTT) which has a time interval measured in time units (TUs). The occurrence of the TBTT means the end of the CAP, after which the normal channel access procedures (EDCA or HCCA) are resumed. When it is determined that the WM is idle at the TxPIFs slot boundary after an HCCA TXOP, the HC can sense the channel and re-request the channel. If the HC does not re-request the channel at the TxPIFS slot boundary after the end of the HCCA TXOP, the CAP ends.

[0019] Figure 1 shows the HCCA TXOP within the Contention Access Phase (CAP), and the CAP showing the EDCA TXOP and access by legacy STAs using the Distributed Coordination Function (DCF). This figure shows Delivery Traffic Indication Messages (DTIMs) having a period value which is a number determining the frequency at which the beacon frame contains a DTIM, and this number is included in each beacon frame. A beacon is visible at the start of each DTIM. During the CAP or HCCA TXOP period in the figure, or during the EDCA TXOP period as shown, the HC can poll the QoS STA during the EDCA TXOP. The CAP consists of not only the HCCA TXOP but also part of the EDCA TXOP.

[0020] 1.3. Types of TXOP The Extended Distributed Channel Access (EDCA) TXOP is a TXOP obtained using an Arbitration Inter Frame Space (AIFS) that prioritizes one Access Category (AC) over other Access Categories (ACs). The length of the EDCA Function (EDCAF) TXOP is specified in the beacon frame.

[0021] The HCCA TXOP is a TXOP obtained using the PIFS.

[0022] The polling type TXOP is the result of the HCCA TXOP being obtained by a QoS(+) CF-Poll from the HC. The length of the polling type TXOP is specified in the QoS(+) CF-Poll frame.

[0023] Figure 2 shows an example of the polling type TXOP. After acquiring the channel access right, the HC polls the QoS STAs in order using the QoS(+) CF-Poll. The non-AP STA that receives the QoS(+) CF-Poll shall respond within the SIFS regardless of the NAV setting.

[0024] If the polled QoS STA does not have the traffic to be transmitted in the queue, or if the MPDU to be transmitted is too long within the specified TXOP limit, the QoS STA shall transmit a QoS(+) Null frame indicating the corresponding queue size for the HC to reallocate the TXOP. Within the polling type TXOP, the STA shall not use the unused part of the TXOP, and the HC can reallocate it. The polling type TXOP is protected by the NAV set by the Duration field of the QoS(+) CF-Poll frame as shown in the figure. All transmissions including the response frames within the polling type TXOP are considered part of the TXOP. All decisions regarding which MAC Service Data Unit (MSDU), A-MSDU, and / or MAC Management Protocol Data Unit (MMPDU) are transmitted during any TXOP are made by the STA holding the TXOP according to the limits of the polling type TXOP.

[0025] Admission Control in 1.4.HC Admission control in HC is used to guarantee the time for which an STA can access the channel. A Hybrid Coordinator (HC) is used to manage admission control within a network.

[0026] The AP uses the ACM (Admission Control Mandatory) subfield advertised within the EDCA parameter set element to indicate whether admission control is required for each AC, and contention-based admission control is utilized. The ACM subfield is assumed to be static over the lifetime of the Basic Service Set (BSS). The STA shall send an ADD Traffic Stream (ADDTS) request frame to the HC to request approval for traffic in either direction that employs an AC that requires admission control.

[0027] The ADDTS request frame shall include the user priority (UP) associated with the traffic and indicate EDCA as the access policy.

[0028] In a non-AP STA, each EDCA function (EDCAF) shall maintain two MAC variables, namely the admitted_time, which is the permitted medium time by the AP, and the amount of used time called used_time. The STA shall calculate the admitted_time of the specified EDCAF after negotiating with the AP through ADDTS request and response frame exchanges. The STA shall update the value of used_time at certain points in time, such as after the success or failure of each frame exchange.

[0029] When the value of used_time reaches or exceeds admitted_time, the corresponding EDCAF shall no longer transmit QoS data frames or QoS Null frames using the EDCA parameters of that AC specified in the QoS parameter set element.

[0030] However, if admission control is not required for these ACs, the STA can choose to temporarily replace the EDCA parameters of its EDCAF with the EDCA parameters specified for a lower priority AC.

[0031] 1.5. Control Access Admission Control The Hybrid Coordinator (HC) is involved in permitting or denying the polling service to the approved TS based on the associated TSPEC. The polling service based on the approved TS provides "guaranteed channel access" from the scheduler to meet its QoS requirements. If the TS is approved by the HC, the scheduler shall provide service to the STA during the service period (SP) that starts at regular time intervals. The AP shall schedule transmissions within the HCCA TXOP and inform the STA of the service schedule. The AP can also update the service schedule later as long as the service schedule meets the TSPEC requirements. The HC can update the service schedule at any time by transmitting the schedule element in the schedule frame. The updated schedule becomes effective when the HC receives the Ack frame for the schedule frame.

[0032] 1.6. QoS(+)CF-Poll Frame Figure 3 shows the format of a QoS(+)CF-Poll frame having the following fields. The Frame control field specifies the protocol version, type, subtype, and corresponding frame control information. The QoS(+)CF-Poll frame means all four QoS data subtypes with CF-Poll, namely the QoS CF-Poll frame, subtype 1110, the QoS CF-Ack+CF-Poll frame, subtype 1111, the QoS data+CF-Poll frame, subtype 1010, and the QoS data+CF-Ack+CF-Poll frame, subtype 1011.

[0033] In a data frame containing QoS CF-Poll, the Duration / ID field value is set to either (a) the time obtained by adding the TXOP limit to one SIFS if the TXOP limit is not 0, or (b) the time obtained by adding two SIFS to the time required for transmitting one MPDU of the nominal MSDU size and the associated Ack frame if the TXOP limit is 0.

[0034] The Address 1 field identifies the intended recipient of the frame, and the Address 2 field identifies the sender of the frame.

[0035] The Sequence Control field specifies the sequence number and fragment number present in the control frame. The QoS Control field identifies various other QoS-related information, A-MSDU-related information, and mesh-related information regarding the frame, which varies depending on the TC or TS to which the frame belongs, as well as the frame type, subtype, and type of the transmitting STA.

[0036] The HT Control field indicates HT control information for HT and VHT variants. The Frame Body field contains information specific to individual frame types and subtypes. The FCS field contains a 32-bit Cyclic Redundancy Check (CRC). The FCS field value is calculated over all fields of the MAC header and the Frame Body field.

[0037] 1.7 TSPEC Elements Figure 4 shows the Traffic Specification (TSPEC) elements used in parameterized QoS admission control. This element provides information elements for management frames (e.g., ADDTS request / response, ADDTS reservation request, DMS request / response, etc.). This element also defines the characteristics of the traffic stream and the QoS expectation.

[0038] The main parameters of the TSPEC include the following. The Delay Bound field specifies, in microseconds, the maximum time allowed for transmitting an MSDU or A-MSDU belonging to the TS of this TSPEC. Service Start Time (μs): Indicates the time when the STA expects to be first ready to transmit frames and when a power-saving (PS) mode STA needs to be awakened to receive these frames.

[0039] The Minimum Service Interval specifies, in microseconds, the minimum interval between the starts of two consecutive SPs.

[0040] The Maximum Service Interval functions as follows. When the TSPEC element is for admitting an HCCA stream, it specifies, in microseconds, the maximum interval between the starts of two consecutive SPs. When the TSPEC element is for EDCA admission control, the Maximum Service Interval field indicates a latency limit that restricts the amount of aggregation (A-MSDU or A-MPDU) used so that no excessive waiting time occurs.

[0041] The Inactivity Interval field specifies, in microseconds, the minimum time that can elapse without an MPDU belonging to that TS arriving or being transferred before the TS is deleted by the MAC entity of the HC.

[0042] The Suspension Interval field specifies, in microseconds, the minimum time that can elapse without an MSDU belonging to that TS arriving or being transferred before the generation of consecutive QoS(+) CF-Polls is suspended for that TS. Certain values, such as 4 294 967 295 (= 232 - 1), disable the suspension interval and indicate that polling for the TS is not interrupted based on inactivity.

[0043] The Service Start Time field specifies, in microseconds, the time at which the first scheduled SP starts. The service start time indicates to the AP the time when the STA is expected to first be ready for frame transmission and power saving (e.g., the M101 - Wi-Fi SiP module). The STA must be powered on to receive frames. If the APSD and schedule subfields are 0, this field is also set to 0 (unspecified).

[0044] The Delay Bound field indicates, in microseconds, the maximum time allowed for transmitting an MSDU or the first MSDU of the MSDUs that make up an A-MSDU belonging to the TS of this TSPEC, measured between the time when the MSDU or the first MSDU of the MSDUs that make up an A-MSDU arrives at the local MAC sublayer from the local MAC SAP and the time when the normal transmission or retransmission of the MSDU or A-MSDU to its destination is completed.

[0045] If there is an associated acknowledgment response frame, the completion of the MSDU or A-MSDU transmission includes the time of transmission of the acknowledgment response frame.

[0046] The Medium Time field includes the time in units of 32 μs / s allowed for access to the medium. This field is reserved in the ADDTS request frame and set by the HC in the ADDTS response frame. This field is not used for control channel access.

[0047] Figure 5 shows the sub-fields within the TS information field shown in Figure 4.

[0048] 2. Motivation and Problems One of the main motivations of the present disclosure is to prevent IDC interference problems on the soft AP side. Normally, the soft AP MLD is designed to communicate with legacy STAs only on the basic link so as to prevent such interference.

[0049] This rule degrades the service quality of legacy STAs by significantly restricting / narrowing the channel resources of legacy STAs. This degradation leads to an increase in latency and a decrease in throughput, which may seriously affect the performance of legacy STAs, especially RTAs.

[0050] When the basic link is a 2.4 GHz and 5 GHz link and the conditional link is a 6 GHz link, the following problems occur. Legacy STAs (e.g., HE STAs) that support 2.4 GHz, 5 GHz, and 6 GHz links waste the advantage of using the 6 GHz channel, which has a much wider bandwidth and lower client density than the basic link.

[0051] When the basic link is a 2.4 GHz and 6 GHz link and the conditional link is a 5 GHz link, the following problems occur. Legacy STAs that support only the 5 GHz channel (e.g., VHT STAs) cannot operate at all. Legacy STAs that support 2.4 GHz and 5 GHz channels (e.g., HT STAs) can only operate at 2.4 GHz, thus wasting all the channel resources of the 5 GHz channel.

[0052] In summary, when a legacy device is only permitted to use basic links, the options of the legacy device are severely restricted. Therefore, in the present disclosure, a system and method for enabling all legacy STAs (HT, VHT, and HE) to operate on conditional links will be described. The legacy device can connect on the conditional link through active or passive scanning. The legacy STA can set up a link connection on the conditional link. When no IDC interference problem occurs in the soft AP MLD, the scheduler must not prevent the legacy STA from using the conditional link.

[0053] 3. Hardware Embodiments The ability to enable a legacy (non-EHT) station to operate on the conditional link of a soft AP MLD can be implemented in various 802.11 hardware configurations shown as an example and not limited to the following.

[0054] 3.1. Station Hardware Configuration FIG. 6 shows an example embodiment 10 of STA hardware configured to execute the protocol of the present disclosure. An external I / O connection 14 is coupled to an internal bus 16 of the circuit 12, and preferably, a CPU 18 and a memory (e.g., RAM) 20 are connected on the internal bus 16 to execute a (single or multiple) program implementing a communication protocol. The host machine houses at least one modem 22 that supports communication, coupled to at least one RF module 24, 28, each of which is connected to one or more antennas 29, 26a, 26b, 26c to 26n. The RF module having a plurality of antennas (e.g., an antenna array) enables beamforming to be performed during transmission and reception. In this way, the STA can transmit signals using multiple sets of beam patterns.

[0055] Bus 14 can connect various devices such as sensors and actuators to the CPU. On processor 18, instructions from memory 20 are executed to run a program that implements a communication protocol to enable the STA to perform the functions of an access point (AP) station or a normal station (non-AP STA). Also, this programming is configured to operate in different modes (TXOP owner, TXOP shared participant, source, intermediate, destination, first AP, other AP, station related to the first AP, station related to other APs, coordinator, coordinatee, AP within OBSS, and STA within OBSS, etc.) according to what role it is playing in the current communication situation.

[0056] Therefore, the illustrated STA HW is composed of at least one modem and associated RF circuitry for providing communication on at least one band. This disclosure is mainly targeted at the sub-6 GHz band.

[0057] It should be understood that this disclosure can be configured using a plurality of modems 22 each coupled to any number of RF circuits. Generally, the more RF circuits used, the wider the coverage of the antenna beam direction. It should be understood that the number of RF circuits and antennas used is determined by the hardware constraints of a particular device. Some of the RF circuits and antennas can be disabled when the STA determines that it does not need to communicate with neighboring STAs. In at least one embodiment, the RF circuit includes a frequency converter and an array antenna controller, etc., and is connected to a plurality of antennas that are controlled to perform beamforming for transmission and reception. In this way, the STA can transmit signals using a set of multiple beam patterns where each beam pattern direction is regarded as an antenna sector.

[0058] Also, multiple instances of local hardware as shown can be combined into a multi-link device (MLD). Usually, this MLD has a processor and memory to coordinate activities, but it is not necessarily the case that each STA within the MLD requires a separate CPU and memory.

[0059] FIG. 7 shows an example embodiment 40 of the hardware configuration of a multi-link device (MLD). A soft AP MLD is an MLD consisting of one or more affiliated STAs operating as an AP. The soft AP MLD should support multiple wireless operations on 2.4 GHz, 5 GHz, and 6 GHz. The basic link set among the multiple wireless links is a link pair that satisfies the simultaneous transmit and receive (STR) mode, such as the basic link set (2.4 GHz and 5 GHz), the basic link set (2.4 GHz and 6 GHz), etc.

[0060] A conditional link is a link that forms a non-simultaneous transmit and receive (NSTR) link pair with some basic link. For example, these link pairs can include a 6 GHz link as a conditional link corresponding to the 5 GHz link when the 5 GHz link is the basic link, and can include a 5 GHz link as a conditional link corresponding to the 6 GHz link when the 6 GHz link is the basic link. The soft AP is used in different scenarios including Wi-Fi hotspots and tethering.

[0061] Multiple STAs belong to the MLD, and each STA operates on links of different frequencies. The MLD has external I / O access to the application, and this access is connected to an MLD management entity 48 having a CPU 62 and memory (e.g., RAM) 64 to enable the execution of a (single or multiple) program that implements a communication protocol at the MLD level. The MLD can here distribute tasks to each affiliated local station exemplified as STA1 42, STA2 44 to STA N46 and collect information from them, and share information among the affiliated STAs.

[0062] In at least one embodiment, each STA of the MLD has its own CPU 50 and memory (RAM) 52, which are coupled via a bus 58 to at least one modem 54 connected to at least one RF circuit 56 having one or more antennas. In this example, the RF circuit has a plurality of antennas 60a, 60b, 60c - 60n in the form of an antenna array. The modem in combination with the RF circuit and the associated (single / multiple) antennas transmits / receives data frames with neighboring STAs. In at least one implementation, the RF module includes a frequency converter, an array antenna controller, and other circuits for interacting with its antennas.

[0063] It should be understood that each STA of the MLD does not necessarily require its own processor and memory, as they can share resources with each other and / or with the MLD management entity depending on the specific MLD implementation. Note that the above MLD diagram is shown as an example and not a limitation, and it should be understood that the present disclosure can operate with a wide range of MLD implementations.

[0064] 4. Network Topology FIG. 8 shows an embodiment of a general multi-link connected network topology example 70. In this figure, the soft AP MLDx 72 is connected to the legacy station 74 and the non-AP STA MLDy 76 via a plurality of wireless links.

[0065] The Soft AP MLD (EHT device) has an identification (ID) denoted as "x", any non-AP MLD (EHT device) has an MLD ID denoted as "y", and any legacy STA (non-EHT device) is exemplified as having an ID as the legacy system (LS) "x, y, z". In this example, the Soft AP MLD x has three affiliated AP stations denoted as APx_1, APx_2, and APx_3. The non-AP MLD y has three affiliated non-AP stations denoted as STAy_1, STAy_2, and STAy_3. APx_1, STAy_1, and LSx operate via Link 1 (L1). APx_2, STAy_2, and LSy operate via Link 2 (L2), and APx_3, STAy_3, and LSz operate via Link 3 (L3).

[0066] FIG. 9 shows an embodiment 90 that exemplifies, for illustrative purposes and not by way of limitation, the network topology to be used. The Soft AP MLD x92 and the non-AP MLD x94 operate on both the 5 GHz 104 and 6 GHz 106 links. LSx100 and LSy102 operate only on the 5 GHz link. LSm96 and LS n98 operate only on the 6 GHz link 106. Since the 2.4 GHz link is a separate basic link that does not suffer from IDC interference from either the 5 GHz link or the 6 GHz link, the following description does not include consideration of the 2.4 GHz link.

[0067] 5. Activation of Legacy STAs on Conditional Links of Soft AP MLD 5.1. Solution 1: Cooperative HCCA Scheduling for NSTR via Basic and Conditional Links FIGS. 10A and 10B show an example embodiment 110 of cooperative HCCA scheduling for NSTR via a basic link 111a and a conditional link 111b.

[0068] The APs on the conditional link and the basic link have the same SME, and in the present disclosure, they are configured to (1) cooperate with each other to process simultaneous EDCA TXOP and HCCA TXOP via the basic link and the conditional link, and (2) perform scheduling and allocation of synchronized UL or DL HCCA TXOP via both links.

[0069] It is assumed that admission control is applied to both links. Initial TS setting and negotiation are mainly performed within the EDCA TXOP (as shown in Example 1-1), and the admitted access policy is HCCA for both the basic link and the conditional link. The MLD listening on both the basic link and the conditional link can execute EDCA access during the EDCA TXOP on both links.

[0070] The AP to which the soft AP MLD belongs is to schedule synchronized HCCA TXOPs 113 and 126 on both links based on the admitted SP information obtained from the TS setting, including at least one of the average data rate, nominal MSDU size, minimum PHY rate, surplus bandwidth allowance, and at least one of the maximum service interval and delay limit, and other desired fields.

[0071] The AP to which the soft AP MLD belongs obtains information such as the TID, traffic in the queue of the STA corresponding to a specific TID, or the next TXOP period requirement of the traffic belonging to a specific TID from the TID subfield and QoS control subfield of all received QoS data frames of the MSDUs. If the request belongs to the TS, the AP can reallocate the TXOP.

[0072] If a stream is added or removed, the AP shall reallocate the HCCA TXOP. The service intervals (SIs) of different approved TSs are not necessarily the same. The AP shall schedule the TXOP as appropriate. Within the HCCA TXOP, there can be multiple frame exchange sequences that follow the TXOP period restrictions. Data exchange as PPDUs on the basic link and conditional link should have both the start time and end time match. This figure shows beacon 112a, 112b, subsequent UL polling type TXOPs 114a, 114b, DL HCCA TXOPs 116a, 116b through the HCCA TXOP to the last UL polling type TXOPs 118a, 118b of the HCCA TXOP period. A PPDU is a physical layer protocol data unit within the protocol and includes a preamble and a data field. Note that for each of these TXOPs, both the start time and end time match between the basic link and the conditional link. Each of these TXOPs also continues to HCCA TXOP 126, exemplified as DL HCCA TXOPs 128a, 128b to UL polling type TXOPs 130a, 130b after another beacon set 124a, 124b in Figure 10B.

[0073] The Soft AP MLD, non-AP MLD, and legacy STA can use any type of padding to match the end time of the transmitted PPDU. The scheduling algorithm between the two links is outside the scope of this proposal. The PS STA shall be activated by the DTIM to receive the beacon and acquire some information such as QoS information and admission information.

[0074] This figure also exemplifies the existence of EDCA TXOP periods 119 and 131. Figure 10A shows EDCA TXOP 120a including CAP 122a and EDCA TXOP 120b with any CAP 122 exemplified near the end. Figure 10B shows EDCA TXOPs 132a, 132b including CAPs 134a, 134b, followed by the transmission of another beacon set 136a, 136b.

[0075] In this solution, access restrictions are assumed to be applied to the basic link and the conditional link. Therefore, the beacon frame shall specify ACM (Admission Control Mandatory) = 1 for all ACs on both links. The TS setting process shall be executed as shown in Example 1-1. During admission control, the soft AP on the basic link and the conditional link shall set the access policy subfield in the TSPEC element to specify HCCA as the access method to be used for the TS, so as to specify the access policy as HCCA in the ADDTS response frame. The non-AP STA that accepts the admission rule shall execute the channel access policy as HCCA.

[0076] Figures 11 and 12A to 12B show Embodiment Examples 150 and 190 of admission control. Admission control by frame exchange of ADDTS request and ADDTS response can be executed based on the non-trigger-based TXOP of all legacy devices (only normal transmissions that do not cause or receive errors due to IDC interference) as shown in Figure 11, or through the trigger-based MU cascading TXOP of HE devices as shown in Figures 12A to 12B.

[0077] FIG. 11 shows an example of TS setting 150 through a non-trigger-based TXOP. It shows the interaction between soft APx_2 152 and LSx100 on the basic link, and between soft APx_3 154 and LSm96 on the conditional link. On the basic link, backoff (BO) 156 is executed and LSx acquires the basic link, and exchanges ADDTS frames with soft APx_2 by sending an ADDTS request 158 and receiving an ADDTS response 162, which is processed according to the cases B-3 to B-6 of Example 1-2 shown in FIG. 15. While LSx is transmitting to soft APx_2 on the basic link, data 160 shown as a UL PPDU can be sent from LSm to soft APx_3 on another link (for example, the conditional link) that does not arbitrarily cause IDC interference on the basic link. On the conditional link, after BO164, another ADDTS request 166 and response 170 are shown while the basic link can be idle 168.

[0078] The initial TS setting sequence for exchanging ADDTS request frames and ADDTS response frames is based on EDCA access, and as shown in the figure (for example, B-3, B-5, and B-7 in FIGS. 15 and 16), the frame exchange may not succeed.

[0079] After the initial TS setting, the exchange of ADDTS request frames and response frames such as update TS setup / negotiation can use an HCCA TXOP that does not follow the process based on the cases B-3 to B-6 of Example 1-2 shown in FIGS. 15 and 16.

[0080] FIGS. 12A and 12B show TS setting 190 through trigger-based TXOP cascading. This figure illustrates a soft AP MLDx192 having APx_1 associated with basic link L1 194, APx_2 associated with basic link L2 196, and APx_3 associated with conditional link L3 198. In this figure, basic link L1 is not used.

[0081] In FIG. 12A, while the conditional link L3 in FIG. 12B is in the idle 200 state, APx_2 on the basic link L2 starts a backoff (BO) 202. When BO 202 counts down to zero, APx_2 and APx_3 simultaneously transmit trigger frames (TF) 206 and 208 on L2 and L3 respectively, to start a simultaneous UL / DL cascade TXOP 204 on L2 and L3 that serves the multi-user (MU) 210 cascading sequence.

[0082] In FIG. 12A, APx_2 can also receive UL MU data 212 as a response to the TF frame 206 from several unicast RUs and allocate (single or multiple) random access RUs (RA-RUs) in TF 206 to receive UL PPDUs. However, this example does not show STAs using RA-RU 212.

[0083] In FIG. 12B, APx_3 receives UL data as a response to TF 208 from one unicast RU and receives two ADDTS request frames from the other two unicast RUs 214. Another RA-RU 214 not used by any STA on L3 is also reserved.

[0084] When APx_2 and APx_3 receive a UL data or ADDTS request frame, they respond with an acknowledgment respectively within the corresponding (single or multiple) unicast RU, and can transmit DL data and / or trigger (TR) frames in a DL cascading sequence as shown in 216, 224, 232 of FIG. 12A and 218, 226, and 234 of FIG. 12B together with a BA or ACK. APx_2 and APx_3 can use the RA-RU frequency slots to transmit several DL data and / or TR frames in a DL cascading sequence as shown in 216 and 224 of FIG. 12A and 218 and 226 of FIG. 12B.

[0085] When the receiving STA receives a TR on the assigned unicast RU (single or multiple), if it has buffered the data and completed the TS setting, it can respond with UL data in the UL cascading sequence as shown in 220, 228 of FIG. 12A and 222, 230 of FIG. 12B. Otherwise, the receiving side can respond without (shown as NONE) in the UL cascading sequence as shown in 222 of FIG. 12B. In the UL cascading sequence as shown in 220, 228 of FIG. 12A and 222, 230 of FIG. 12B, an RA-RU is reserved for (OFDMA) - based random access (UORA).

[0086] In FIG. 12B, after APx_3 responds with ACK218 to the ADDTS request frame 214 on the (single or multiple) unicast RU, it can respond with an ADDTS response frame 226 using this (single or multiple) RU and also transmit DL data and / or a trigger (TR) frame in the DL cascading sequence as shown in 226 of FIG. 12B.

[0087] From this figure, it can be seen that the TS setting is executed during the TB cascade transmission. The non - AP station transmits an ADDTS request frame using a specific RU assigned by the AP and receives an ADDTS response frame. The ADDTS response frame can be transmitted in the next TXOP if it cannot be transmitted in the current TXOP. The TS setting can also be executed during the transmission of only TB UL. In this case, the ADDTS response frame should match the ACK / BA frame transmitted on another (single or multiple) RU.

[0088] 5.1.1. Solution 1 - 2: Tx and Rx between the soft AP and the non - AP MLD in the EDCA TXOP FIG. 13 shows an example embodiment 250 of a second solution showing Tx and Rx between a soft AP MLD and a non-AP MLD in an EDCA TXOP. Soft APs APx_2 252a and APx_3 252b are APs belonging to the same soft AP MLD, and non-AP STAs STAx_2 254a and STAx_3 254b are non-AP STAs belonging to the same non-AP MLD.

[0089] Section A-1 258a starts after APx_2 first acquires (obtains) channel access rights on the basic link (256a). APx_2 transmits a DL PPDU 260 on the basic link, while APx_3 transmits a DL PPDU in synchronization with APx_2 if access is possible on the conditional link, or does not transmit otherwise. Thereafter, the non-AP station transmits a BA 262 simultaneously on the basic link and the conditional link as a response to receiving the DL data.

[0090] In section A-2 258b, APx_3 acquires the conditional link (256b). If the basic link is available, APx_2 and APx_3 transmit a DL PPDU and then a BA simultaneously, or do not transmit otherwise, and reset the EDCA on the conditional link.

[0091] In section A-3 258c, non-AP STA STAx_2 transmits a UL PPDU on the basic link after acquiring the basic link 256c, while on the conditional link, non-AP STA STAx_3 synchronously transmits a UL PPDU if access is available, and a BA 262 as a response to receiving the UL PPDU on each link is seen. If access is not available on the conditional link, no transmission occurs on the conditional link.

[0092] In section A-4 258d, non-AP STAx_3 detects that the conditional link is idle and terminates the BO count when competing for the link. If the basic link is available, non-AP STAx_2 and non-AP STAx_3 simultaneously transmit UL PPDUs and simultaneously receive BAs. Otherwise, they do not transmit and reset the EDCA on the conditional link.

[0093] Note that the availability of access on the conditional link can be determined by PIFS detection, and whether access is available on the basic link can be determined by the EDCA rule.

[0094] Figure 14 shows another embodiment example 290 where LSx294a and LSm294b are legacy stations operating on the basic link and conditional link respectively related to APx_2 292a and APx_3 292b. APx_2 292a and APx_3 292b are APs belonging to the same soft AP MLD.

[0095] It is assumed that the AP belonging to the soft AP MLD can detect whether the received PPDU is from an EHT device or a non-EHT device (legacy device) based on the preamble of the PPDU. When the soft AP MLD receives a non-EHT PPDU, it can perform different responses as shown in the figure.

[0096] In section B-1 298a, APx_2 acquires the channel access right on the basic link (296a) and transmits the DL PPDU300. When the conditional link is available, APx_3 synchronously transmits another DL PPDU302 that coincides with the DL PPDU300 transmitted on the basic link at the end time. On the other hand, when the conditional link is not available, APx_3 does not transmit the DL PPDU. When LSx and LSm receive the coinciding DL PPDUs on the basic link and conditional link, they simultaneously respond with the coinciding BA304 on the corresponding link.

[0097] In section B-2 298b, APx_3 obtains conditional link access (296b). If the basic link is available, APx_2 and APx_3 can transmit their respective matching BAs 304 after simultaneously (matching) transmitting the DL PPDU 300. On the other hand, if the basic link is not available, APx_3 should not transmit, and the EDCA on the conditional link is reset.

[0098] FIG. 15 shows an embodiment 330 showing another example of legacy stations LSx 294a and LSm 294b operating on the basic link and the conditional link respectively associated with APx_2 292a and APx_3 292b. APx_2 292a and APx_3 292b are APs belonging to the same soft AP MLD.

[0099] In section B-3 333a, after LSx first acquires (obtains) the basic link for a non-TB UL transmission (332a), it can transmit the UL PPDU 334 on the basic link and then perform an RTS-CTS frame exchange with APx_2.

[0100] On the conditional link, if access is available and APx_3 can match the frame exchange sequence of the conditional link with that of the basic link, APx_3 should start the UL TB PPDU simultaneously with APx_2. Otherwise, APx_3 should not transmit the frame triggering the UL PPDU nor respond to the received UL PPDU.

[0101] Any UL PPDU on the conditional link that is not synchronized with any UL PPDU on the basic link may be subject to IDC interference 338 at APx_3 due to simultaneous DL TX on the basic link such as BA 336.

[0102] In section B-4 333b, APx_2 first obtains a basic link for TB UL transmission (332b) and starts a TB UL TXOP. It can be seen that on the basic link and the conditional link, after a trigger frame (TF) 342, if available, a UL PPDU is transmitted. If APx_3 cannot use the conditional link simultaneously with APx_2, it should not transmit a UL PPDU. A BA is transmitted in response to any UL PPDU.

[0103] In section B-5 333c, since the current basic link is idle, LSm obtains a conditional link for UL TX (332c) and starts transmitting a UL PPDU 340 on the conditional link. However, if APx_2 obtains the basic link and starts transmitting a DL PPDU, the UL PPDU on this conditional link is not sensed by APx_3. Therefore, the UL PPDU on the conditional link is in progress and will be subject to IDC interference when a DL PPDU is transmitted on the basic link. The DL PPDU on the basic link can be an immediate response to a previously received frame or an emergency DL PPDU that needs to be transmitted immediately.

[0104] In section B-6 333d, APx_3 obtains a conditional link for trigger UL TX (332c). If the basic link is available, APx_2 and APx_3 shall start a trigger for simultaneously triggering a UL PPDU. Otherwise, APx_3 should not transmit anything and should reset the EDCA on the conditional link.

[0105] FIG. 16 shows an exemplary embodiment 390 showing another example of operations on the basic link and the conditional link. It can be seen that legacy stations LSx394a and LSm394b are operating on the basic link and the conditional link respectively related to APx_2 392a and APx_3 392b. APx_2 392a and APx_3 392b are APs belonging to the same soft AP MLD.

[0106] In section B-7 400, when the conditional link is CCA busy 398, the APx_2 of the soft AP MLDx first acquires the basic link (396). After the APx_2 transmits the DL PPDU 402 on the basic link, it receives the BA 406. On the conditional link, since it is CCA busy 398, the APx_3 cannot transmit the DL PPDU and cannot detect the end of the CCA busy due to the interference of the DL TX from the basic link. Due to the IDC interference, the UL PPDU 404 from the LSm on the conditional link cannot be sensed.

[0107] Note that when the soft AP MLD communicates with different non-AP STAs via different links that are not from the same non-AP MLD, the non-AP STAs do not recognize each other's TX / RX status, and thus the channel access situation is covered by B1 to B7 in the previous figure.

[0108] Figures 17A to 17E show an example embodiment 430 of the soft AP MLD communication with a legacy station (LS) during the EDCA TXOP.

[0109] In Figure 17A, a check 432 is performed to determine whether the AP of the soft AP MLD has acquired (obtained) the basic link channel access right. If the AP of the soft AP MLD has acquired the basic link, it is necessary to determine in check 434 whether it is necessary to transmit a (single or multiple) DL PPDU to the legacy system (LS). If the AP of the soft AP MLD needs to transmit a (single or multiple) DL PPDU to the LS on the basic link, it is determined in block 436 whether the conditional link is idle. If the conditional link is idle, in block 438, the basic link AP and the conditional link AP of the same soft AP MLD transmit the DL PPDU simultaneously to maintain the alignment, and the process ends in Figure 17E.

[0110] On the other hand, if the AP of the soft AP MLD has not obtained the basic link in block 432, the execution proceeds to block 448 in FIG. 17C to check whether the AP of the soft AP MLD has obtained (acquired) a conditional link. If the conditional link has not been obtained, the execution proceeds to block 462 in FIG. 17D to check whether the legacy system (LS) has obtained the basic link. If not, the execution proceeds to block 470 in FIG. 17E to check whether the LS has obtained the conditional link. If not, since the link has not been obtained, the process ends.

[0111] Returning to block 448 in FIG. 17C, if the condition is satisfied and the AP of the soft AP MLD has obtained (acquired) the conditional link, the execution proceeds to block 450 to check whether the conditional link AP needs to transmit a DL PPDU to the legacy system (LS). If this condition is not satisfied, the execution proceeds to block 456 to determine whether the conditional link AP needs to trigger a UL PPDU. If this condition is not satisfied, the process ends in FIG. 17E. Otherwise, the AP needs to trigger a (single or multiple) UL PPDU, and the execution proceeds to check 458 to determine whether the basic link is idle at this time. If the basic link is not idle, the execution proceeds to block 454 (described later) in this figure. If the basic link is idle, in block 460, the basic link AP and the conditional link AP of the same soft AP MLD trigger a UL PPDU at the same time and the process ends.

[0112] Next, returning to the description of block 450, if the conditional link AP needs to send a DL PPDU to the LS, the execution reaches block 452 to determine whether the basic link is idle. If the basic link is idle, the execution proceeds to block 438 in FIG. 17A, where the basic link AP and the conditional link AP of the same soft AP MLD simultaneously send a DL PPDU and the process ends. On the other hand, if it is determined in block 452 that the basic link is not idle, in block 454, the conditional link AP determines that the transmission of the DL / UL PPDU is not permitted and the process ends.

[0113] Next, returning to the description of block 434 in FIG. 17A, if the condition that the basic link AP needs to send a DL PPDU to the LS is not satisfied, a check is performed in block 440 of FIG. 17B to determine whether the basic link AP needs to trigger a UL PPDU. If this condition is not satisfied, the execution ends in FIG. 17E. Otherwise, it reaches block 442 to determine whether the conditional link is idle. If the conditional link is not idle, it is determined in block 446 that only the basic link AP should perform the transmission and the execution ends. On the other hand, if the conditional link is idle in block 442, after both the basic link AP and the conditional link AP simultaneously send a UL PPDU in block 444, this process ends.

[0114] Returning to block 436 in FIG. 17A, if the conditional link is not idle, the execution reaches block 446 in FIG. 17B where it is determined that only the basic link AP should perform the transmission and this process ends.

[0115] Next, returning to block 462 in FIG. 17D, if LS has obtained the basic link, the execution proceeds to block 464 to check whether the conditional link AP can schedule a simultaneous UL TXOP with the basic link. If the condition is met, at block 466, the conditional link AP and the basic link AP schedule a simultaneous UL TXOP, and this process ends. On the other hand, if the condition is not met, at block 468, the basic link AP executes a UL TXOP with LS, but the conditional link AP does not transmit the PPDU, and the process ends.

[0116] Next, returning to block 470 in FIG. 17E, if LS has obtained the conditional link, the execution reaches block 472 to determine whether the basic link is available. If the basic link is available, at block 474, the basic link AP and the conditional link AP schedule the transmission of a simultaneous UL TXOP, and then the process ends. On the other hand, if the basic link is not available, at block 476, the conditional link AP is not permitted to transmit the PPDU, and the process ends.

[0117] 5.2. Simultaneous UL / DL HCCA TXOP The scheduled simultaneous UL / DL TXOP can be applied to (a) legacy STAs, (b) stations to which (the same or different) non-AP MLDS belong, and (c) stations to which non-AP MLDS and legacy STAs on the basic link or conditional link belong.

[0118] FIG. 18 shows an exemplary embodiment 510 of the scheduled simultaneous UL / DL TXOP. Both APs belonging to the same soft AP MLD acquire both the basic link 512 and the conditional link 514 simultaneously when these two links are idle at the TxPIFS slot boundary. All stations follow the HCF NAV rule, and each frame transmitted under HCF includes a NAV period value.

[0119] If the AP has no more STAs to poll and no more data frames, management frames, Block Ack Request frames, or Block Ack frames to transmit, the RA can reset the NAV of all QoS STAs within the BSS by transmitting a QoS CF-Poll frame in which the period / ID field is set to 0 and the address 1 field matches the RA's own MAC address.

[0120] When the STA receives a frame addressed to itself and requests an acknowledgment, it shall respond with an Ack or QoS+CF-ACK frame regardless of the NAV. The non-AP STA shall accept a polling-type TXOP by starting a frame exchange sequence regardless of the NAV.

[0121] In the UL TXOP of FIG. 18, the AP to which the soft AP MLD belongs polls these non-AP stations simultaneously by assigning the same polling-type TXOP period to the non-AP stations operating on the basic link and the conditional link. The polling-type TXOP periods 516a, 516b, 518a, 518b, 520a, 520b, 522a, 522b on the basic link and the conditional link are scheduled according to the traffic conditions of the polled stations.

[0122] The polled non-AP station (which is a non-AP QoS STA whose address matches the address 1 field of the received QoS CF-Poll frame) shall not exceed the polling-type TXOP period and can use any type of padding or frame aggregation to maintain the PPDU end time alignment on the basic link and the conditional link.

[0123] If a polled non-AP station uses only a part of the assigned TXOP, the receiving AP shall not perform polling until the polling-type TXOP of the other link is completed. The AP to which the soft AP MLD belongs shall perform polling simultaneously. A polled non-AP station can transmit multiple frame exchange sequences within a given polling-type TXOP in accordance with the TXOP period limit.

[0124] In the DL TXOP of FIG. 18, it is assumed that the AP to which the soft AP MLD belongs simultaneously transmits DL PPDUs to non-AP stations operating on each link by assigning the same HCCA TXOP period to them. The AP to which the soft AP MLD belongs can transmit multiple frame exchange sequences within a given polling-type TXOP in accordance with the TXOP period limit. The AP to which the soft AP MLD belongs can use any padding to match the end times of the transmitted PPDUs.

[0125] 5.2.1. Cooperative Scheduling of Periodic HCCA TXOPs on Basic Links and Conditional Links FIG. 19 shows an example embodiment 550 of cooperative scheduling.

[0126] In block 552, a check is performed to determine whether the same soft AP MLD's AP has acquired (obtained) the basic link and the conditional link. If the condition is not satisfied, after waiting (554), the check is repeated (within the limit). If the condition is satisfied, in block 556, a check is performed to determine whether the soft AP MLD needs to transmit a DL PPDU. If the condition is satisfied, in block 558, the basic link AP and the conditional link AP simultaneously start a DL HCCA PPDU on the basic link and the conditional link, and the process ends. On the other hand, if the condition in block 556 is not satisfied, in block 560, a check is performed to determine whether the soft AP MLD needs to poll a UL PPDU. If polling is not required, the process ends. Otherwise, in block 562, the basic link AP and the conditional link AP simultaneously start a UL polling type TXOP on the basic link and the conditional link, and the process ends.

[0127] 5.3. Example 1-3-1: Recovery from Absence of Expected Reception FIG. 20 shows a topology 590 of Example 1-3-1 regarding the problem of recovery from the absence of expected reception in a hidden terminal situation. Note that the separation between 5 GHz and 6 GHz in the figure represents only the separation of frequency bands, not spatial separation. This figure shows a soft AP MLDy 592 operating on both 5 GHz 608 and 6 GHz 612, each having an affiliated AP such as soft APy_2 and soft APy_3, and a soft AP MLDx 594 operating on both 5 GHz 606 and 6 GHz 610, each having an affiliated AP such as soft APx_2 and soft APx_3. Soft APy_2, soft APy_3, soft APx_2, and soft APx_3 are not shown. The non-AP MLDx 600 operates on both links of 5 GHz 606 and 6 GHz 610 using non-AP STAs such as non-AP STAx_2 and non-AP STAx_3. Non-AP STAx_2 and non-AP STAx_3 are not shown.

[0128] The legacy stations LSx602 and LSy598 are related to one of the APs to which the soft AP MLDx594 operating at 5 GHz belongs. The legacy stations LSm604 and LSn596 are related to one of the APs to which the soft AP MLDx594 operating at 6 GHz belongs. LSy and LSn are respectively located within the coverage ranges of the APs to which the soft APs MLDy on 5 GHz and 6 GHz belong.

[0129] This figure shows an example of a collision occurring between a QoS CF-Poll frame and other management frames in a hidden terminal scenario. Assume that the soft APx_3 of the soft AP MLDx and the soft APy_3 of the soft AP MLDy operate on a 6 GHz channel and cannot sense each other. A collision occurs when the soft APx_3 and the soft APy_3 transmit frames simultaneously and arrive at LSn596. Note that interference frames may not be transmitted to LSn, and the arrows indicate frames that can be sensed by a specific station rather than frames addressed to a specific station.

[0130] Figure 21 shows Example 1-3-1 630, which is an example of an embodiment of a solution to the collision problem caused by the hidden AP problem in Figure 20. This figure shows the interactions between the soft APx_2 632 and LSy598, between the soft APx_3 634 and LSn596, and between the soft APy_3 636 and LSn596. Note that in the figure, LSn is shown as communicating and interacting on two lines. It should be understood that the reason for this is that LSn is involved in the communication between hidden terminals, and one of the hidden terminals is communicating with LSn while the other is interfering with LSn.

[0131] To solve the collision problem caused by a hidden AP transmitting a management frame on one link (e.g., a 6 GHz link), in at least one embodiment of the present disclosure, instead of immediately transmitting a QoS CF-Poll at the start of a TXOP, because the recovery / retransmission time on one link may be affected by the polled UL PPDU size on the other link, a very small (compact) DL PPDU that does not carry a data payload is transmitted.

[0132] In the figure, the soft AP y_3 executes a backoff 638, and the soft APs x_2 and x_3 are also competing for channel access rights. When the soft AP y_3 finishes its backoff countdown and the soft APs x_2 and x_3 detect channel idle at the TxPIFs boundary 640, each of them acquires its respective link simultaneously.

[0133] In the solution to this 1-3-1 problem, when the primary link and the conditional link are idle at the TxPIFS slot boundary, both APs belonging to the soft AP MLDx transmit very small (compact) DL PPDU frames 644 and 645 (e.g., RTS, null, control, or management frames) on both links simultaneously, and element (a) where a NAV 642 that protects the duration of the TXOP in response to the start of the DL PPDU transmission is seen is executed. However, at this same time, the soft AP y_3 transmits a complete DL PPDU 648.

[0134] The condition of element (a) includes (a)(i) indicating that there is a possibility of collision if any AP station cannot receive a CTS / ACK / BA as a response to the DL PPDU after SIFS 646. The retransmission process should (a) repeat this short DL PPDU transmission. Thus, the soft APs x_2 and x_3 acquire the channel again and transmit short DL PPDUs 652 and 656, and NAVs 654 and 660 are started, and it can be seen that the soft AP y_3 is busy 658.

[0135] (a)(ii) If both AP stations receive CTS / ACK / BA as responses 662 and 664 of the DL PPDU after SIFS, they shall poll for the UL TXOPs (666 and 668), or transmit DL TXOPs simultaneously on both the basic link and the conditional link using the updated NAV period 654.

[0136] (a)(iii) Both APs belonging to the soft AP MLDx can limit the number of retransmissions of small DL PPDU frames via both links (when soft APy_3 transmits a very long DL PPDU). If the retransmission meets the retransmission limit, the AP shall receive CTS / ACK / BA as a response to the DL PPDU after SIFS and poll for the UL TXOP, or transmit the DL TXOP alone. An AP that does not receive CTS / ACK / BA as a response to the DL PPDU shall neither poll for the UL TXOP nor transmit the DL TXOP.

[0137] After the CF polling, it can be seen that LSy and LSn transmit UL PPDUs 670 and 672 to the soft AP MLD and receive BAs 674 and 676 from the soft AP MLD.

[0138] FIG. 22 shows topology example 690 of Example 1-3-2 regarding the recovery problem from the absence of expected reception in a hidden terminal in a CFP situation where a collision occurs between QoS CF-poll frames using HCCA. This figure is a modification of FIG. 20, and also shows a soft AP MLDy592 operating on both 5 GHz 608 and 6 GHz 612, each having an associated AP such as soft APy_2 and soft APy_3, and a soft AP MLDx594 operating on both 5 GHz 606 and 6 GHz 610, each having an associated AP such as soft APx_2 and soft APx_3, and soft APy_2, soft APy_3, soft APx_2, and soft APx_3 are not shown. Non-AP MLDx600 operates on both links of 5 GHz 606 and 6 GHz 610 using non-AP STAs such as non-AP STAx_2 and non-AP STAx_3 respectively. Non-AP STAx_2 and non-AP STAx_3 are not shown.

[0139] Legacy stations LSx602 and LSy598 are associated with one of the APs to which the soft AP MLDx594 operating on 5 GHz belongs. Legacy stations LSm604 and LSn596 are associated with one of the APs to which the soft AP MLDx594 operating on 6 GHz belongs. LSy and LSn are located within the coverage ranges of the APs to which the soft AP MLDy belongs on the 5 GHz link and the 6 GHz link respectively.

[0140] This figure shows an example of a collision of QoS CF-Poll frames due to the hidden terminal problem. Soft AP MLDx and soft AP MLDy operate on 5 GHz and 6 GHz links and cannot sense each other. A collision occurs when the APs to which soft APx belongs and the APs to which soft APy belongs simultaneously transmit QoS CF-Poll frames to LSn on the 6 GHz link and LSy on the 5 GHz link.

[0141] Example 1-3-2 710 showing an embodiment of a recovery scheme for the collision problem caused by hidden terminals in a CFP at the start of an HCCA TXOP is shown in FIG. 23. This figure shows the interactions between Soft APx_2 712 and LSy598, between Soft APy_2 714 and LSy598, between Soft APx_3 716 and LSn596, and between Soft APy_3 718 and LSn596.

[0142] To solve the collision problem caused by hidden terminals, QoS CF-Poll frames are transmitted according to the HCCA policy. This process is the same as that described in element (a) of Example 1-3-1 in FIG. 21.

[0143] (a)(i) Any AP indicates that there may be a collision if it cannot receive CTS / ACK / BA as a response to the DL PPDU after SIFS. However, if step (a) is processed directly, subsequent collisions may occur. To avoid subsequent collisions, the simultaneous recovery and / or retransmission of each Soft AP MLD can be started after aSIFSTime + n*aSlotTime, where the random variable is n.

[0144] (a)(ii) This process is the same as that described for (a)(ii) in Example 1-3-1.

[0145] This figure shows that the Soft AP acquires a link at the TxPIFs slot boundary 722 (720) and each transmits a DL PPDU 724. Since these Soft APs do not receive responses to the DL PPDU, they re - compete for channel access rights. Soft APx_2 and Soft APx_3 re - compete for the channel after the SIFS time, and Soft APy_2 and Soft APy_3 re - compete for the channel after SIFS + 2*SlotTime. Then, after SIFS, Soft APx_2 and Soft APx_3 acquire the channel again and transmit short DL PPDUs 730 and 736, NAVs 734 and 740 are started, and it can be seen that Soft APy_2 and 3APy_3 are busy 732 and 738. Both stations of APx_2 and APx_3 poll for the UL TXOP (748 and 750) when receiving CTS / ACK / BA as responses 742 and 746 to the DL PPDU after SIFS. UL PPDUs 752 and 754 are received, and then the AP responds with the relevant BAs 756 and 758.

[0146] 5.3.1. Solution 2: Adaptive Polling - based Scheduling on Conditional Links According to the Basic Link Situation Figure 24 shows an example embodiment 790 of adaptive polling - based scheduling on conditional links according to the basic link situation.

[0147] Stations operating on the basic link access the channel using the EDCA policy. Legacy (non - EHT) devices access the conditional link based on the HCCA policy. EHT devices can access the conditional link either through EDCA or through HEMM which is a hybrid mode of HCCA and EDCA. All stations follow the HCF's NAV rules.

[0148] Since the AP to which the Soft AP MLD belongs has the same station management entity (SME), it recognizes UL / DL transmissions on the basic link. The AP of the Soft AP MLD on the conditional link shall schedule UL / DL transmissions on the conditional link according to simultaneous UL / DL transmissions on the basic link.

[0149] The AP of the Soft AP MLD on the conditional link can negotiate with non-AP legacy STAs during admission control to agree on a large maximum service interval (SI) value. If the AP of the Soft AP MLD cannot provide a TS at the scheduled timing due to simultaneous transmission and reception via the basic link and conditional link, or interference on the conditional link, it can use the maximum SI of the admitted traffic stream (TS) for scheduling. The next service start time meets the maximum SI value admitted on the conditional link, but if there is one or more HCCA TXOP schedules on the conditional link that result in asynchronous UL / DL transmissions with simultaneous basic link transmissions, the AP of the Soft AP MLD on the conditional link should not provide a TS.

[0150] The AP of the Soft AP MLD gives the STA a polling-type TXOP with a period specified in the QoS(+)CF-Poll frame. In the polling-type TXOP, one or more frame exchanges can occur, and it is assumed that the start time and end time of the frame exchange sequences on the basic link and the conditional link are the same.

[0151] FIG. 24 shows an embodiment example 790 in which a STA operating on a basic link 792 accesses a channel based on an EDCA policy, and a legacy (non-EHT) device accesses a conditional link 794 using an HCCA policy. A BO 796 is seen on the basic link, and when the BO counts down to zero, the conditional link is detected as idle at a TxPIF boundary 798. Accordingly, when an EDCA UL TXOP 800 starts on the basic link, a UL polling type TXOP 802 is executed on the conditional link at the same time. Similar examples are also seen for an EDCA DL TXOP 804 on the basic link and a simultaneous DL HCCA TXOP 806 on the conditional link. Also, after the BO, an EDCA DL TXOP 808 starts on the basic link, and a simultaneous DL HCCA TXOP 810 starts on the conditional link. Then, after the BO, an EDCA UL TXOP 812 starts on the basic link, and a simultaneous UL Polled TXOP 814 starts on the conditional link.

[0152] 5.4. Admission Control: Conditional Links for Polling-Based Access Only In this solution, it is assumed that access restrictions are applied only to devices operating on a conditional link. Accordingly, the following applies to the conditional link. The beacon frame sets (specifies) a first state (e.g., "1") where ACM (Admission Control Mandatory) = true for all ACs. The TS setting process is assumed to be executed as described in Example 1-1. When the AP receives an ADDTS request during admission control, it can distinguish between an EHT PPDU and a non-EHT PPDU from header information and the like.

[0153] During admission control, the following applies. When an ADDTS request is received from a non-EHT device (legacy device), the soft AP on the conditional link shall send an ADDTS response frame to the legacy device and specify the channel access policy as HCCA by setting the access policy subfield in the TSPEC element indicating that the approved TS is HCCA. When an ADDTS request is received from an EHT device, the soft AP on the conditional link shall specify the channel access policy as EDCA or HEMM.

[0154] Non-AP legacy STAs and non-AP EHT devices operating on a conditional link that accept admission rules shall comply with the access policy agreed upon during admission control.

[0155] 5.4.1. Example 2-1: UL TXOP Alignment FIG. 25 shows an exemplary embodiment 830 showing the UL TXOP alignment of Example 2-1. This figure shows the interactions between APx_2 832 and LSx602, between APx_3 834 and LSm604, between APx_2 836 and non-AP STAx_2 837, and between APx_3 838 and non-AP STAx_3 839.

[0156] In section (A) of the figure, the basic link AP of the soft AP MLD executes a backoff 840 and sends a TF842 to start a trigger-based UL TXOP for non-EHT devices. During the TF, APx_3 of the same AP MLD can detect that the conditional link is idle at the TxPIFs boundary and simultaneously poll any non-EHT device 844 on the conditional link. The AP receives UL PPDUs 850 and 852 and responds to them with a BA858.

[0157] In section (B) of the figure, a non-EHT device starts a UL TXOP on the basic link along with an RTS frame 860 after BO840. The AP responds with CTS864, and during this time, the conditional link AP of the same AP MLD polls any non-EHT device on the conditional link 866 if it detects that the channel is idle at the TxPIFs boundary. The AP receives UL PPDUs 872 and 874 and responds to them with BA858.

[0158] In section (C) of the figure, the basic link AP of the soft AP MLD starts a UL TXOP for the EHT device using TF846. Simultaneously with TF846, the AP of the soft AP MLD sends TF / QoS CF-Polls 848 on the conditional link if it detects that the channel is idle at the TxPIFs boundary. The AP receives UL PPDUs 854 and 856 and responds to them with BA.

[0159] In section (D) of the figure, the EHT device on the basic link starts a UL TXOP for the soft AP MLD with an RTS frame 862 after BO840, to which the AP responds with CTS868. Simultaneously with CTS868, the AP of the soft AP MLD sends a TF / QoS CF-Poll 870 on the conditional link. The AP receives UL PPDUs 876 and optionally 878 and responds to them with BA.

[0160] The soft AP SME shall ensure the alignment of each simultaneous UL and DL transmission. If the conditional link is busy (e.g., due to overlapping basic service set (OBSS) interference), the conditional link AP shall not send TF / Poll / CTS frames on the conditional link.

[0161] 5.4.2. Example 2-2: DL TXOP Alignment FIG. 26 shows an embodiment example 930 of the DL TXOP alignment of Example 2-2. As shown in the topology example of FIG. 9, it shows the stations with interactions between APx_2 832 and LSx100, between APx_3 834 and LSm96, between APx_2 836 and non-AP STAx_2 94a, and between APx_3 838 and non-AP STAx_3 94b.

[0162] In section (A) of the figure, it can be seen that the basic link AP of the soft AP MLD starts a DL TXOP for non-EHT devices after BO932. The DL TXOP is indicated by DL PPDU934 and BA response 946. When a conditional link is available as shown, the conditional link AP of the same soft AP MLD shall start a DL TXOP for non-EHT devices operating on the conditional link after detecting the idle of the conditional link at the TxPIFs boundary, where the end times of each DL PPDU936 match through fragmentation or padding 944.

[0163] In section (B) of the figure, the basic link AP of the Soft AP MLD starts a DL TXOP for the EHT device after BO932. The DL TXOP is indicated by DL PPDU938 and BA response 946. If a conditional link is available as illustrated here, the conditional link AP of the same Soft AP MLD can transmit DL PPDU940 simultaneously after detecting that the conditional link is idle at the TxPIFs boundary. If the conditional link AP does not have a DL PPDU to transmit, this DL PPDU can be a single DL NULL PPDU with NAV set as the simultaneous DL TXOP on the basic link. If the conditional link AP has a DL PPDU to transmit after transmitting the DL NULL PPDU, it can transmit DL PPDU 942 whose end matches the DL PPDU of the basic link after detecting the idleness of the conditional link at the TxPIFs boundary on the conditional link. Here, a gap occurs between the DL PPDUs, and it can be seen that non-AP STAx_3 performs CCA sensing over the PIFS period to acquire the channel and transmits another DL PPDU942 to match the DL PPDU of the basic link.

[0164] (A) and (B) both state that if a conditional link is not available, the AP of the conditional link must not transmit a DL PPDU on the conditional link.

[0165] Figures 27A to 27D show an embodiment example 970 of a TXOP scheduled on a conditional link according to the basic link status. In this scheduled TXOP process, at check 972, it is determined whether the conditional link is idle. If the conditional link is not idle, the process ends in Figure 27D. Otherwise, at block 974, it is checked whether the AP of the soft AP MLD has obtained the basic link and started the TB UL TXOP. If this condition is met, at block 976, the AP of the same soft AP MLD transmits a trigger frame or a poll frame on the conditional link simultaneously with the trigger frame on the basic link. Execution reaches block 978, where the polling type UP TXOP sets the same TXOP period as the simultaneous UL TXOP on the basic link.

[0166] Execution proceeds to block 994 in Figure 27C, where it is checked whether the polling STA on the conditional link has a UL PPDU to transmit. If the UL PPDU exists, at block 996, each UL PPDU on the conditional link is transmitted to match the UL PPDU on the basic link. At block 998, after the AP of the soft AP MLD receives the UL PPDU, it responds with an ACK / BA simultaneously on the basic link and the conditional link, and then the process ends.

[0167] Next, returning to block 994, if the polled STA does not have a UL PPDU to transmit, only the UL PPDU is transmitted on the basic link at block 1000, and the STA on the conditional link is not permitted access to the conditional link until the NAV expires. Then, at block 1002, after the AP of the soft AP MLD receives the UL PPDU on the basic link, it responds with an ACK / BA, and then the process ends.

[0168] Return to block 974 in FIG. 27A. If the soft AP MLD has not acquired the basic link to start the TB UL TXOP, it reaches block 980. At block 980, it checks whether the AP of the soft AP MLD has received a Request-To-Send (RTS) from the non-AP STA. If this condition is met, at block 982, the AP sends a Clear-To-Send (CTS) as a response. Then, at block 984, the AP of the same soft AP MLD sends a polling frame on the conditional link simultaneously with the CTS frame on the basic link, and the execution reaches block 978 described above.

[0169] Next, return to block 980. If the AP of the soft AP MLD has not received an RTS from the non-AP STA, the execution proceeds to block 986 in FIG. 27B. At block 986, it checks whether the AP of the soft AP MLD has acquired the basic link and started the DL TXOP. If the condition is not met, the process ends in FIG. 27D. Otherwise, since the AP of the soft AP MLD has acquired the basic link and started the DL TXOP, at block 988, it checks whether the AP of the same soft AP MLD has a DL PPDU to send to any non-AP STA on the conditional link.

[0170] If the condition is met, at block 990, the conditional link AP starts a DL TXOP having the same TXOP period as the simultaneous DL TXOP on the basic link, and the execution proceeds to block 1004 in FIG. 27D. At block 1004, padding is applied to match the end time of each DL PPDU on the conditional link with the DL PPDU on the basic link. Then, at block 1006, the AP of the soft AP MLD simultaneously receives an ACK / BA as a response to the DL PPDU from the non-AP STA, and then this process ends.

[0171] Next, returning to block 988 in FIG. 27B, if the AP of the same soft AP MLD does not have a DL PPDU to be sent to any non-AP STA on the conditional link, the execution reaches block 992, and the AP of the conditional link can send a DL NULL PPDU having the same NAV period as the simultaneous DL TXOP period on the basic link, and then the execution proceeds to block 1008 in FIG. 27D.

[0172] In decision block 1008, it is checked whether the conditional link AP has a DL PPDU to be sent after the DL NULL PPDU and before the simultaneous DL PPDU on the basic link ends. If the condition is not met, in block 1012, the AP of the soft AP MLD receives an ACK / BA as a response to the DL PPDU on the basic link and the process ends.

[0173] On the other hand, if the condition in block 1008 is met, in block 1010, the conditional link AP sends a DL PPDU whose end time coincides with the simultaneous DL PPDU on the basic link and the process ends.

[0174] 6. Summary A legacy (non-EHT) device can establish a link connection on a conditional link. The scheduler shall not prevent a legacy STA from using the conditional link if there is no IDC interference problem for the soft AP MLD.

[0175] 6.1. Methodology 1: Cooperative HCCA Scheduling for Simultaneous Transmissions and Receivings via Basic Link and Conditional Link (1) Assume that the APs on the conditional link and the basic link belonging to the same soft AP MLD have the same SME and cooperate with each other to process simultaneous EDCA TXOP and HCCA TXOP via the basic link and the conditional link.

[0176] (2) Admission control is applied to both links. TS setting / negotiation shall mainly proceed with EDCA TXOP, and the schedule of HCCA TXOP shall be based on the approved SP information obtained from the TS setting. The approved access policy shall be HCCA on the basic link and the conditional link.

[0177] (3) APs belonging to the same soft AP MLD shall schedule and allocate synchronized UL or DL TXOPs via both the basic link and the conditional link during the HCCA TXOP period. (a) APs belonging to the same soft AP MLD can schedule synchronized HCCA TXOPs based on the approved SP information obtained from the TS setting, such as, for example, the average data rate, nominal MSDU size, minimum PHY rate, surplus bandwidth allowance, and at least one of the maximum service interval and delay limit. APs belonging to the soft AP MLD obtain information from the TID subfield and QoS control subfield of all received QoS data frames of MSDUs, such as, for example, TID, traffic in the queue of the STA corresponding to a specific TID, or the next TXOP period requirement for traffic belonging to a specific TID. If the request belongs to the TS, the AP can reallocate the TXOP.

[0178] (4) When a stream is added or deleted, the scheduler shall reallocate the HCCA TXOP.

[0179] (5) The service intervals (SIs) of different approved TSs are not necessarily the same. The AP shall schedule the TXOP as appropriate.

[0180] (6) Within the HCCA TXOP, there can be multiple frame exchange sequences that comply with the TXOP period limit. The PPDUs on the basic link and the conditional link shall have the same start time and end time.

[0181] (7) The Soft AP MLD, non-AP MLD, and legacy STA can use any type of padding to align the end time of the transmitted PPDU.

[0182] (8) The simultaneously scheduled UL / DL HCCA TXOP can be applied to a) legacy STAs, b) stations to which (the same or different) non-AP MLDS belong, and c) stations to which non-AP MLDS and legacy STAs on the basic link and conditional link belong.

[0183] (9) Both APs belonging to the Soft AP MLD acquire both these links simultaneously when the basic link and conditional link are idle at the TxPIFS slot boundary.

[0184] (10) All stations follow the HCF's NAV rules, and each frame transmitted under HCF includes a NAV period value. (a) When the AP has no more STAs to poll and no more data frames, management frames, Block Ack Request frames, or Block Ack frames to transmit, the AP can reset the NAV of all QoS STAs in the BSS by transmitting a QoS CF-Poll frame with the RA matching its own MAC address and the period / ID field set to 0. (b) When a STA receives a frame addressed to itself and requests an acknowledgment response, it shall respond with an Ack or QoS+CF-Ack frame regardless of the NAV. A non-AP STA shall accept a polling-type TXOP by starting a frame exchange sequence regardless of the NAV.

[0185] (11) When scheduling a UL HCCA TXOP (a) The AP belonging to the Soft AP MLD polls non-AP stations operating on the basic link and conditional link simultaneously and assigns the same polling-type TXOP period. (b) (A non-AP QoS STA that matches its own address in the address 1 field of the received QoS CF-Poll frame) The polled non-AP station shall not exceed the polling type TXOP period and can use any type of padding to maintain the coincidence of the PPDU end times on the basic link and the conditional link. (b) (i) If the polled non-AP station uses only a part of the assigned TXOP, the receiving AP shall not perform polling until the polling type TXOP of the other link ends. The APs to which the soft AP MLD belongs shall perform polling simultaneously. (b) (ii) The polled non-AP station can transmit multiple frame exchange sequences within a given polling type TXOP according to the TXOP period limit.

[0186] (12) In the case of a scheduled DL HCCA TXOP (a) The AP to which the soft AP MLD belongs shall simultaneously transmit DL PPDUs to non-AP stations operating on each link and allocate the same HCCA TXOP period. (b) The AP to which the soft AP MLD belongs can transmit multiple frame exchange sequences within a given polling type TXOP according to the TXOP period limit. (c) The AP to which the soft AP MLD belongs can use any padding to match the end times of the transmitted PPDUs.

[0187] (13) To avoid collisions caused by hidden terminals, when the basic link and the conditional link are idle at the TxPIFS slot boundary, both APs belonging to the soft AP MLDx simultaneously transmit very small (compact) DL PPDU frames (e.g., RTS, NULL, control, or management frames) on both links, and the DL PPDU has a NAV setting that protects the TXOP period.

[0188] (a) If any AP station cannot receive CTS / ACK / BA as a response to the DL PPDU after SIFS, it indicates the possibility of a collision. The process can repeat step (13) after aSIFSTime + n*aSlotTime, where n is a random variable.

[0189] (b) If both AP stations receive CTS / ACK / BA as a response to the DL PPDU after SIFS, they shall poll for the UL TXOP or set the updated NAV period and simultaneously transmit the DL TXOP on both the basic link and the conditional link.

[0190] (c) Both AP stations of the same soft AP MLD that handle the retransmission of small DL PPDUs can limit the retransmission time via both links (when an interfering AP, which is a hidden terminal, transmits a very long DL PPDU as interference). If the retransmission meets the retransmission limit, the AP should receive CTS / ACK / BA as a response to the short DL PPDU after SIFS and poll for the UL TXOP or transmit the DL TXOP alone. An AP that does not receive CTS / ACK / BA as a response to the DL PPDU should not poll for the UL TXOP nor transmit the DL TXOP.

[0191] (14) The PS STA shall obtain any QoS and admission information from the beacon.

[0192] 6.2. Methodology 2: Adaptive polling-based schedule on conditional links according to the basic link situation. (1) Stations operating on the basic link access the channel based on the EDCA policy.

[0193] (2) Legacy (non-EHT) devices shall access the conditional link based on the HCCA policy. EHT devices can access the conditional link through EDCA or through HEMM, which is a hybrid mode of HCCA and EDCA.

[0194] (3) Since the conditional link AP and the basic link AP of the same soft AP MLD have the same SME, the conditional link AP recognizes UL / DL transmissions on the basic link.

[0195] (4) The conditional link AP schedules UL / DL transmissions on the conditional link according to simultaneous UL / DL transmissions on the basic link.

[0196] (5) In a scheduled TXOP on the conditional link, one or more frame exchanges can occur. The start time and end time of each PPDU in the frame exchange sequence on the conditional link shall match those of the PPDU on the basic link.

[0197] (6) The soft AP MLD, non-AP MLD, and legacy STA can use any type of padding to align the end time of the transmitted PPDU.

[0198] (7) All stations follow the HCF NAV rule of Methodology 1 (the same as (3)).

[0199] (8) The AP of the soft AP MLD on the conditional link can negotiate with the non-AP legacy STA during admission control to agree on a large maximum SI value.

[0200] (a) If the AP of the soft AP MLD cannot provide a TS at the scheduled timing due to simultaneous transmission and reception via the basic link and the conditional link, or interference on the conditional link, the maximum SI of the admitted TS can be used for scheduling.

[0201] (b) If the next service start time meets the admitted maximum SI value on the conditional link, but there is any HCCA TXOP schedule on the conditional link that results in asynchronous UL / DL transmissions with simultaneous basic link transmissions, the AP of the soft AP MLD on the conditional link should not provide a TS.

[0202] (9) In a scheduled UL TXOP, if a conditional link is available, the conditional link AP shall transmit a polling frame to a non-EHT device on the conditional link when the QoS CF-Poll can match a trigger frame (UL TXOP started by the AP) or a CTS frame (UL TXOP started by a non-AP) transmitted by the basic link AP belonging to the same soft AP MLD.

[0203] (10) In a scheduled DL TXOP, if a conditional link is available, the conditional link APs of the same soft AP MLD shall transmit DL PPDUs simultaneously with the basic link AP. If the conditional link AP does not have a DL PPDU to transmit, it can transmit a single DL NULL PPDU with the NAV set as a simultaneous DL TXOP on the basic link. If the conditional link AP has a DL PPDU to transmit after transmitting the DL NULL PPDU, it can transmit a DL PPDU whose end matches the DL PPDU on the basic link on the conditional link.

[0204] (11) In a scheduled UL / DL TXOP, if a conditional link is not available, the AP of the conditional link shall not transmit a DL PPDU on the conditional link.

[0205] 7. General Scope of the Embodiment In this specification, embodiments of the present technology can be described with reference to methods and systems, and / or procedures, algorithms, steps, operations, mathematical formulas, or other computational representations in the form of a flowchart that can also be implemented as a computer program product. In this regard, each block or step of the flowchart, and combinations of blocks (and / or steps) of the flowchart, as well as any procedure, algorithm, step, operation, mathematical formula, or computational representation can be implemented by various means such as software including one or more computer program instructions embodied in the form of hardware, firmware, and / or computer-readable program code. As will be understood, such any computer program instructions can be executed by one or more computer processors including, but not limited to, a general-purpose computer or a dedicated computer, or any other programmable processing device for producing a machine, so that the computer program instructions executed on the computer processor or other programmable processing device can create means for performing the specified (single or plural) functions.

[0206] Accordingly, the blocks of the flowchart described in this specification, as well as procedures, algorithms, steps, operations, mathematical formulas, or computational representations support computer program instructions that embody in the form of combinations of means for performing specified (single or plural) functions, combinations of steps for performing specified (single or plural) functions, and computer-readable program code logic means for performing specified (single or plural) functions. Also, it will be understood that each block of the flowchart described in this specification, as well as any procedure, algorithm, step, operation, mathematical formula, or computational representation, and combinations thereof can also be implemented by a dedicated hardware-based computer system for performing specified functions or steps, or a combination of dedicated hardware and computer-readable program code.

[0207] Furthermore, these computer program instructions, embodied in the form of computer-readable program code, can be stored in one or more computer-readable memories or memory devices that direct a computer processor or other programmable processing apparatus to function in a particular manner, such that the instructions stored in these computer-readable memories or memory devices produce an article of manufacture that includes instruction means for performing the functions specified within the block(s) of the flowchart(s). The computer program instructions can be executed by a computer processor or other programmable processing apparatus, causing a series of operational steps to be executed on the computer processor or other programmable processing apparatus to generate a computer-implemented process, and the instructions executed on the computer processor or other programmable processing apparatus can provide steps for performing the functions specified within the block(s), procedure(s), algorithm(s), step(s), operation(s), mathematical expression(s), or computational representation(s) of the flowchart(s).

[0208] Furthermore, as used herein, the terms "program" or "program implementation statement" will be understood to mean one or more instructions executable by one or more computer processors to perform one or more of the functions described herein. The instructions can be embodied in software, firmware, or a combination of software and firmware. The instructions can be stored locally on a non-transitory medium of the device, or remotely, such as on a server, or a combination of local and remote storage of all or part of the instructions can be used. Remotely stored instructions can be automatically downloaded (pushed) to the device by a user's initiation or based on one or more factors.

[0209] Furthermore, the terms processor, hardware processor, computer processor, central processing unit (CPU), and computer as used herein are used synonymously to denote a device capable of executing instructions and communicating with an input / output interface and / or peripheral devices, and the terms processor, hardware processor, computer processor, CPU, and computer are intended to include single or multiple devices, single-core devices and multi-core devices, and variants thereof.

[0210] From the description herein, it will be understood that the present disclosure includes a plurality of technical implementations including, but not limited to, the following.

[0211] An apparatus for wireless communication in a network, comprising: (a) a wireless communication circuit of a soft access point (AP) multi-link device (MLD) configured to wirelessly communicate with other wireless stations (STAs) via a basic link and a conditional link when performing multi-link operation (MLO) on a wireless local area network (WLAN) according to the IEEE 802 protocol, and configured to enable a legacy (non-EHT) device to set up a link connection on the conditional link; (b) a processor coupled to the wireless communication circuit and operating as an STA on the WLAN; (c) a non-transitory memory storing instructions executable by the processor for communicating with other STAs; (d) the instructions, when executed by the processor, cause: (d)(i) the soft AP MLD to have an AP STA communicating via the basic link and an AP STA communicating via the conditional link; (d)(ii) the soft AP MLD to have station management entities (SMEs) that cooperate with each other such that the AP STAs on the basic link and the conditional link simultaneously process an extended distributed channel access (EDCA) transmission opportunity (TXOP) and a high throughput control channel access (HCCA) TXOP via the basic link and the conditional link; (d)(iii) perform admission control on both the basic link and the conditional link, and proceed with the setup and negotiation of a traffic stream (TS) in the EDCA TXOP, while the scheduling of the HCCA TXOP is based on approved service period (SP) information in which an access policy approved for HCCA on both the basic link and the conditional link, obtained during the TS setup, is utilized; (d)(iv) an AP belonging to the same soft AP MLD to schedule and allocate a synchronized uplink (UL) or downlink (DL) TXOP via both the basic link and the conditional link during the HCCA TXOP period.

[0212] An apparatus for wireless communication in a network, comprising: (a) a wireless communication circuit of a soft access point (AP) multi-link device (MLD) configured to wirelessly communicate with other wireless stations (STAs) via a basic link and a conditional link when performing multi-link operation (MLO) on a wireless local area network (WLAN) according to the IEEE 802 protocol, and configured to enable a legacy (non-EHT) device to set up a link connection on the conditional link; (b) a processor coupled to the wireless communication circuit and operating as an STA on the WLAN; (c) a non-transitory memory storing instructions executable by the processor for communicating with other STAs; (d) the instructions, when executed by the processor, (d)(i) access the basic link based on an extended distributed channel access (EDCA) policy; (d)(ii) access the conditional link based on a Hybrid Coordination Function Controlled Channel Access (HCCA) policy for a legacy station that is not configured to operate at extremely high throughput (EHT) and is thus a non-EHT STA; (d)(iii) access the conditional link through either EDCA or a Hybrid EDCA and HCCA Mode (HEMM); (d)(iv) since the AP accessing the conditional link and the AP accessing the basic link of the same soft AP MLD share a Station Management Entity (SME), recognize that UL / DL transmission is being performed on the basic link; (d)(v) schedule a transmission opportunity (TXOP) as UL / DL transmission on the conditional link by the AP of the conditional link according to simultaneous UL / DL transmission on the basic link; (d)(vi) communicate one or more frames of a Physical Layer Protocol Data Unit (PPDU) in a frame exchange sequence during the scheduled TXOP on the conditional link, and the start time and end time of each PPDU in the frame exchange sequence on the conditional link match the PPDU communicated on the basic link, the apparatus performing one or more steps including the above.

[0213] A wireless communication method in a network, comprising: (a) performing multi-link operation (MLO) on a wireless local area network (WLAN) according to an IEEE 802 protocol configured to enable a legacy (non-EHT) device to set up a link connection on a conditional link, and performing wireless communication between a soft access point (AP) multi-link device (MLD) and another wireless station (STA) via a basic link and a conditional link; (b) the soft AP MLD having an AP STA communicating via the basic link and an AP STA communicating via the conditional link; (c) the soft AP MLD having a station management entity (SME) that cooperates with each other so that the AP STA on the basic link and the AP STA on the conditional link simultaneously process an extended distributed channel access (EDCA) transmission opportunity (TXOP) and a high throughput control channel access (HCCA) TXOP via the basic link and the conditional link; (d) performing admission control on both the basic link and the conditional link, and while setting and negotiating a traffic stream (TS) in the EDCA TXOP, scheduling of the HCCA TXOP is based on approved service period (SP) information in which an access policy approved for HCCA on both the basic link and the conditional link, obtained during TS setting, is used; (e) APs belonging to the same soft AP MLD scheduling and allocating synchronized uplink (UL) or downlink (DL) TXOPs via both the basic link and the conditional link during the HCCA TXOP period.

[0214] A wireless communication method in a network, comprising: when performing multi-link operation (MLO) on a wireless local area network (WLAN) according to an IEEE 802 protocol configured to enable a legacy (non-EHT) device to set up a link connection on a conditional link, wirelessly communicating between a soft access point (AP) multi-link device (MLD) and another wireless station (STA) via a basic link and a conditional link; accessing the basic link based on an extended distributed channel access (EDCA) policy; accessing the conditional link based on a Hybrid Coordination Function Controlled Channel Access (HCCA) policy for a legacy station that is not configured to operate at extremely high throughput (EHT) and is thus a non-EHT STA; accessing the conditional link through either EDCA or a Hybrid HCCA-EDCA Mode (HEMM); since the AP accessing the conditional link and the AP accessing the basic link of the same soft AP MLD share a Station Management Entity (SME), the access point (AP) accessing the conditional link recognizes that uplink / downlink (UL / DL) transmission is being performed on the basic link; scheduling a transmission opportunity (TXOP) as UL / DL transmission on the conditional link by the AP of the conditional link according to simultaneous UL / DL transmission on the basic link; and during the scheduled TXOP on the conditional link, communicating one or more frames of a Physical Layer Protocol Data Unit (PPDU) in a frame exchange sequence, wherein the start time and end time of each PPDU in the frame exchange sequence on the conditional link match the PPDU communicated on the basic link.

[0215] During the HCCA TXOP period, scheduling and allocating a synchronized UL or DL TXOP via both the basic link and the conditional link involves: (a) the AP to which the soft AP MLD belongs schedules a synchronized HCCA TXOP based on the approved SP information obtained from the TS settings; (b) obtaining information regarding in-queue traffic for the AP STA corresponding to a specific traffic identifier (TID) or the next TXOP period request for traffic belonging to a specific TID from the TID subfield and the Quality of Service (QoS) control subfield of the received QoS data frames of all MAC service data units (MSDUs); and (c) the AP of the soft AP MLD being configured to reallocate the TXOP if the request belongs to a given TS. This includes any prior implementation's apparatus or method.

[0216] The approved SP information from the TS settings is selected from a group of communication information consisting of at least one of the average data rate, nominal MSDU size, minimum PHY rate, excess bandwidth allowance, and at least one of the maximum service interval and delay boundary. This includes any prior implementation's apparatus or method.

[0217] The HCCA TXOP is reallocated by the STA's scheduler when a stream is added or removed. This includes any prior implementation's apparatus or method.

[0218] Since the AP is configured to schedule the TXOP appropriately, the service intervals (SIs) of different approved traffic streams (TSs) do not have to be the same. This includes any prior implementation's apparatus or method.

[0219] Within the HCCA TXOP, multiple frame exchange sequences can be executed under the condition that it is restricted to the TXOP period and each PPDU on the basic link and the conditional link has matching start and end times. This includes any prior implementation's apparatus or method.

[0220] An apparatus or method of any previous implementation that can utilize padding to match the end times of each transmitted PPDU.

[0221] An apparatus or method of any previous implementation in which a legacy STA, or a STA to which a same or different non-AP MLD belongs, or a STA to which a non-AP MLD and a legacy STA belong can utilize a simultaneously scheduled UL / DL HCCA TXOP on a basic link and a conditional link.

[0222] An apparatus or method of any previous implementation in which an AP belonging to a soft AP MLD acquires both links simultaneously when both the basic link and the conditional link are idle at a transmission PCF Inter Frame Space (PIFS), i.e., at a TxPIFS slot boundary.

[0223] An apparatus or method of any previous implementation in which all STAs follow the HCF NAV rule and each frame transmitted under HCF includes a NAV period value.

[0224] During the scheduling of a UL HCCA TXOP, (a) the AP to which a soft AP MLD belongs polls non-AP stations operating on both the basic link and the conditional link simultaneously to allocate the same polling type TXOP period, (b) a polled non-AP station that is a non-AP QoS STA whose address 1 field of the received QoS CF-Poll frame matches the local station's address is not permitted to exceed the polling type TXOP period, and (b)(i) when the polled non-AP station uses only a part of the assigned TXOP, the receiving AP does not perform polling until the polling type TXOP on the other link is completed and the AP to which the soft AP MLD belongs performs polling simultaneously, and / or (b)(ii) the polled non-AP station transmits a plurality of frame exchange sequences within a given polling type TXOP on the condition that it is restricted by the TXOP period. An apparatus or method of any previous implementation.

[0225] Scheduling for DL HCCA TXOP is performed, and (a) the AP to which the soft AP MLD belongs assigns the same HCCA TXOP period to non-AP stations operating on each link to simultaneously transmit DL PPDUs to them, (b) the AP to which the soft AP MLD belongs transmits multiple frame exchange sequences within a given polling-type TXOP in accordance with the TXOP period limit, and (c) the AP to which the soft AP MLD belongs can use padding to align the end times of the transmitted PPDUs, a device or method of any previous implementation.

[0226] To avoid collisions by hidden terminals, both APs belonging to the soft AP MLD simultaneously transmit DL PPDU frames without data payloads on the primary link and the conditional link when both links are idle at the TxPIFS slot boundary, and the DL PPDU has a NAV setting to protect the TXOP period, a device or method of any previous implementation.

[0227] The DL PPDU frame is selected from a group of frames consisting of a request to send (RTS) frame, a null frame, a control frame, or a management frame, a device or method of any previous implementation.

[0228] The power saving (PS) station obtains QoS and admission information from the received beacon frame, a device or method of any previous implementation.

[0229] The AP of the conditional link of the soft AP MLD negotiates with the non-AP legacy STA during admission control to agree on a large maximum SI value, a device or method of any previous implementation.

[0230] If a conditional link can be used to execute a scheduled UL TXOP, the AP of the conditional link may send a polling frame to a non-EHT STA on the conditional link when a quality of service (QoS) contention-free (CF) poll can match the trigger frame of an uplink (UL) TXOP initiated by the AP, or the clear to send (CTS) frame of a non-AP-initiated UL TXOP sent by the AP of a basic link belonging to the same soft AP MLD. Any prior implementation device or method.

[0231] If a conditional link can be used for a scheduled DL TXOP, the AP of the conditional link of the same soft AP MLD may send a simultaneous downlink (DL) PPDU as if it were executed on a basic link. Any prior implementation device or method.

[0232] If the AP of the conditional link does not have a DL PPDU to send, it may send a single DL NULL PPDU with the NAV set as a simultaneous DL TXOP on the basic link. Any prior implementation device or method.

[0233] If the AP of the conditional link has a DL PPDU to send after sending a DL NULL PPDU, it may send a DL PPDU that matches the end of the DL PPDU on the basic link on the conditional link. Any prior implementation device or method.

[0234] If a conditional link cannot be used for a scheduled UL / DL TXOP, the AP of the conditional link may not send a DL PPDU on the conditional link. Any prior implementation device or method.

[0235] As used herein, the term "implementation" is intended to include, without limitation, embodiments, examples, or other forms for practicing the technology described herein.

[0236] As used herein, the singular forms "a," "an," and "the" include the plural reference unless the context clearly dictates otherwise. A reference to an item in the singular is not meant to mean "only one" unless explicitly stated as such, but rather "one or more than one."

[0237] Expressions such as "A, B, and / or C" in the present disclosure represent that any one of A, B, or C, or any combination of items A, B, and C, may exist. An expression structure indicating that a group of elements listed after "at least one of" follows, when applicable, indicates that at least one of these listed elements exists, including any conceivable combination of these listed elements.

[0238] References to the phrases "an embodiment," "at least one embodiment," or similar phrases in the present disclosure indicate that a particular feature, structure, or characteristic described in connection with the described embodiment is included in at least one embodiment of the present disclosure. Accordingly, these various embodiments' expressions do not necessarily mean all the same embodiment or a particular embodiment different from all other described embodiments. The expression "embodiment" should be interpreted to mean that a particular feature, structure, or characteristic of a given embodiment can be combined in any suitable form in one or more embodiments of the disclosed device, system, or method.

[0239] The term "set" as used herein means a collection of one or more items. Thus, for example, a set of items can include a single item or multiple items.

[0240] Relational terms such as first and second, top and bottom, etc. in this document are used only to distinguish one entity or action from another entity or action, and do not necessarily require or imply any actual relationship or order between such entities or actions.

[0241] The terms "comprises", "comprising", "has", "having", "includes", "including", "contains", "containing", or any other variations of these terms are intended to include non-exclusive inclusion. Thus, a process, method, article, or apparatus that comprises, has, or includes a list of elements does not include only those elements but may also include other elements not expressly listed or inherent to such process, method, article, or apparatus. Elements followed by "comprises... a", "has... a", "includes... a", or "contains... a" do not preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises, has, or includes that element, without further limitation.

[0242] The terms "approximately", "approximate", "substantially", "essentially", and "about", or any variations thereof, as used herein are for the purpose of describing and accounting for minor variations. These terms, when used in relation to an event or situation, can mean that the event or situation will occur without fail, and when the likelihood of such event or situation occurring is very high. These terms, when used in relation to a numerical value, can mean a variation range of ±10% or less, such as ±5% or less, ±4% or less, ±3% or less, ±2% or less, ±1% or less, ±0.5% or less, ±0.1% or less, or ±0.05% or less of that numerical value. For example, "substantially" aligned can mean an angular variation range of ±10° or less, such as ±5° or less, ±4° or less, ±3° or less, ±2° or less, ±1° or less, ±0.5° or less, ±0.1° or less, or ±0.05° or less.

[0243] In addition, in this specification, amounts, ratios, and other numerical values may be presented in a range format. Such a range format is used for convenience and simplicity, and includes the numerical values clearly specified as the limits of the range. However, it should be understood flexibly that all individual numerical values or partial ranges included in this range are also included as if each of these numerical values and partial ranges were clearly indicated. For example, a ratio within the range of about 1 to about 200 includes the clearly enumerated limit values of about 1 and about 200, but it should also be understood to include individual ratios such as about 2, about 3, about 4, etc., and partial ranges such as about 10 to about 50, about 20 to about 100, etc.

[0244] As used herein, the term "coupled" is defined as "connected", but it is not necessarily a direct mechanical connection. A device or structure "configured" in a particular form is configured at least in that form, but it can also be configured in forms not listed.

[0245] Advantages, benefits, problem-solving means, and any (single or plural) elements that give rise to or make more prominent any advantage, benefit, or solution should not be construed as important, necessary, or essential features or elements of the technology described herein, or of some or all of the claims.

[0246] Also, in the above disclosure, for the purpose of rationalizing the disclosure, various features can be grouped together in various embodiments. The method of this disclosure should not be construed as reflecting an intention that the embodiments described in the claims require more features than those explicitly described in each claim. The subject matter of the present invention can be implemented by less than all the features of a single disclosed embodiment.

[0247] The abstract of this disclosure is presented with the understanding that it is not used to interpret or limit the scope of the claims or their meaning, but rather to enable a reader to quickly ascertain the essence of the technical disclosure.

[0248] Depending on the jurisdiction, it should be understood that there is also a practice of seeking deletion of one or more portions of the present disclosure after filing. Accordingly, the reader should refer to the application as filed at the filing date for the original content of the present disclosure. Any deletion of the disclosed content should not be construed as a waiver, forfeiture, or dedication to the public of any subject matter of the application as originally filed.

[0249] The following claims are incorporated into the present disclosure in a manner that each claim stands on its own as a separate inventive subject matter.

[0250] Although the description herein contains many details, these should not be construed as limiting the scope of the present disclosure, but rather as merely exemplifying some of the presently preferred embodiments. Accordingly, it will be understood that the scope of the present disclosure fully encompasses other embodiments that would be apparent to those skilled in the art.

[0251] Structural and functional equivalents of elements of embodiments of the present disclosure well-known to those skilled in the art are also expressly incorporated herein by reference and are intended to be included within the scope of the present claims. Further, elements, components, or method steps of the present disclosure are not intended to be generally disclosed as such, whether or not they are expressly recited in the claims. With respect to the elements of the claims herein, unless an element is expressly recited using the phrase "means for", it should not be construed as a "means-plus-function" element. Also, with respect to the elements of the claims herein, unless an element is expressly recited using the phrase "step for", it should not be construed as a "step-plus-function" element.

Description of Reference Numerals

[0252] 96 LSm 100 LSx 150 Embodiment Example 152 Soft APx_2 154 Soft APx_3 156 BO 158 ADDTS Request 160 UL PPDU 162 ADDTS Response 164 BO 166 ADDTS Request 168 Idle 170 ADDTS Response

Claims

1. An apparatus for wireless communication in a network, comprising: (a) a wireless communication circuit of a software access point (AP) multi-link device (MLD) configured to wirelessly communicate with other wireless stations (STAs) via a basic link and a conditional link when performing multi-link operation (MLO) on a wireless local area network (WLAN) according to the IEEE 802 protocol, and configured to enable a legacy (non-EHT) device to set up a link connection on the conditional link; (b) a processor coupled to the wireless communication circuit and operating as an STA on the wireless local area network (WLAN); (c) a non-transitory memory storing instructions executable by the processor for communicating with other STAs; wherein (d) the instructions, when executed by the processor, cause the apparatus to: (i) the software access point (AP) multi-link device (MLD) to have an AP STA communicating via the basic link and an AP STA communicating via the conditional link; (ii) the software access point (AP) multi-link device (MLD) to have a station management entity (SME) that cooperates with each other such that the AP STAs on the basic link and the AP STAs on the conditional link simultaneously process an extended distributed channel access (EDCA) transmission opportunity (TXOP) and a hybrid coordination function (HCF) controlled channel access (HCCA) TXOP via the basic link and the conditional link; (iii) perform admission control on both the basic link and the conditional link, and proceed with the setup and negotiation of a traffic stream (TS) in the EDCA TXOP, while the scheduling of the HCCA TXOP is based on approved service period (SP) information of an access policy approved for the HCCA on both the basic link and the conditional link obtained during the TS setup; (iv) an AP belonging to the same software AP MLD to schedule and allocate a synchronized uplink (UL) or downlink (DL) TXOP via both the basic link and the conditional link during the HCCA TXOP period; perform one or more steps including; An apparatus characterized by the above.

2. During the HCC A TXOP period, scheduling and allocating a synchronized UL or DL TXOP via both the basic link and the conditional link is (a) the AP to which the soft access point (AP) multi-link device (MLD) belongs schedules a synchronized HCC A TXOP based on the approved SP information obtained from the TS setting; (b) obtaining information regarding traffic in the queue for the AP STA corresponding to a specific traffic identifier (TID), or a request for the next TXOP period for traffic belonging to a specific TID, from the TID subfield and the quality of service (QoS) control subfield of the received QoS data frame of all MAC service data units (MSDUs); (c) when the TXOP period request belongs to a given TS, the AP of the soft access point (AP) MLD is configured to reallocate the TXOP. The apparatus according to claim 1, comprising.

3. The approved SP information from the TS setting is selected from a group of communication information consisting of an average data rate, a nominal MSDU size, a minimum PHY rate, an excess bandwidth allowance, and at least one of a maximum service interval and a delay boundary. The apparatus according to claim 1.

4. The HCC A TXOP is reallocated by the STA's scheduler when a stream is added or removed. The apparatus according to claim 1.

5. Since the AP is configured to schedule the TXOP appropriately, the service intervals (SIs) of different approved traffic streams (TSs) do not have to be the same. The apparatus according to claim 1.

6. Within the HCC A TXOP, multiple frame exchange sequences can be executed under the condition that each PPDU on the basic link and the conditional link has a matching start time and end time, limited to the duration of the TXOP. The apparatus according to claim 1.

7. Padding is used to match the end times of each transmitted PPDU. The apparatus according to claim 1.

8. On the basic link and the conditional link, UL / DL HCCCA TXOPs scheduled simultaneously are utilized by a legacy STA, or a STA to which the same or different non-AP MLDs belong, or a STA to which a non-AP MLD and a legacy STA belong. The apparatus according to claim 1.

9. When both the basic link and the conditional link are idle at the transmission PCF frame interspace (PIFS), i.e., the T x PIFS slot boundary, the AP belonging to the soft access point (AP) multi-link device (MLD) acquires both links simultaneously. The apparatus according to claim 1.

10. All STAs follow the NAV rules of the HCF, and each frame transmitted under the HCF includes a NAV period value. The apparatus according to claim 1.

11. During the scheduling of an uplink (UL) HCCCA TXOP, (a) The AP belonging to the soft access point (AP) multi-link device (MLD) polls non-AP stations operating on the basic link and the conditional link simultaneously to allocate the same polling type TXOP period. (b) A polled non-AP station that is a non-AP QoS STA whose address 1 field of the received QoS CF-Poll frame matches the station's own address is not permitted to exceed the polling type TXOP period. (i) When the polled non-AP station uses only a part of the assigned TXOP, the receiving AP does not perform polling until the polling type TXOP on the other link is completed and the AP belonging to the soft AP MLD performs polling simultaneously, and / or (ii) The polled non-AP station transmits a plurality of frame exchange sequences within a given polling type TXOP on the condition that it is restricted by the TXOP period. The apparatus according to claim 1.

12. Scheduling for a DL HCCCA TXOP is executed. (a) The AP belonging to the soft access point (AP) multi-link device (MLD) transmits DL PPDUs to the non-AP stations simultaneously by allocating the same HCCCA TXOP period to the non-AP stations operating on each link. (b) The AP to which the soft access point (AP) multi-link device (MLD) belongs transmits a plurality of frame exchange sequences within a given polling-type TXOP in accordance with the TXOP period limit. (c) The AP to which the soft access point (AP) multi-link device (MLD) belongs uses padding to align the end times of the transmitted PPDUs. (2) The apparatus according to claim 1. (13) To avoid collisions by hidden terminals, both APs belonging to the soft access point (AP) multi-link device (MLD) simultaneously transmit a DL PPDU frame without a data payload on both the primary link and the conditional link when both links are idle at the TxPIFS slot boundary. The DL PPDU has a NAV setting to protect the TXOP period. (2) The apparatus according to claim 1. (14) (7) The DL PPDU frame without a data payload is selected from a group of frames consisting of a request to send (RTS) frame, a null frame, a control frame, or a management frame. (2) The apparatus according to claim 1. (15) A power saving (PS) station obtains QoS and admission information from the received beacon frame. (2) The apparatus according to claim 1. (16) (1) An apparatus for wireless communication in a network, (a) configured to wirelessly communicate with other wireless stations (STAs) via a primary link and a conditional link when performing multi-link operation (MLO) on a wireless local area network (WLAN) according to the IEEE 802 protocol, and configured to enable a legacy (non-EHT) device to establish a link connection on the conditional link; a wireless communication circuit of a soft access point (AP) multi-link device (MLD); (b) a processor coupled to the wireless communication circuit and operating as an STA on the wireless local area network (WLAN); (c) a non-transitory memory storing instructions executable by the processor for communicating with other STAs; comprising, and (d) the instructions, when executed by the processor, (i) accessing the primary link based on an extended distributed channel access (EDCA) policy; (ii) not configured to operate at extremely high throughput (EHT), and thus accessing a conditional link based on a Hybrid Coordination Function (HCF) Controlled Channel Access (HCCA) policy for a legacy station that is a non-EHT STA, and (iii) accessing the conditional link through either Enhanced Distributed Channel Access (EDCA) or a Hybrid of HCCA-EDCA Mixed Mode (HEMM), and (iv) since the AP accessing the conditional link of the same soft AP MLD and the AP accessing the basic link share a Station Management Entity (SME), the access point (AP) accessing the conditional link recognizes that uplink / downlink (UL / DL) transmission is being performed on the basic link, and (v) scheduling a Transmission Opportunity (TXOP) as UL / DL transmission on the conditional link by the AP of the conditional link according to simultaneous UL / DL transmission on the basic link, and (vi) communicating one or more frames of a Physical Layer Protocol Data Unit (PPDU) in a frame exchange sequence during a scheduled TXOP on the conditional link, and the start time and end time of each PPDU in the frame exchange sequence on the conditional link being consistent with the PPDU communicated on the basic link, and performing one or more steps including an apparatus characterized by the above. **Claim 17** Padding can be used to match the end time of the transmitted PPDU, The apparatus according to claim 16. **Claim 18** The STA follows the Network Allocation Vector (NAV) rules of the Hybrid Coordination Function (HCF) under IEEE 802.11, The apparatus according to claim 16. **Claim 19** The AP of the conditional link of the soft access point (AP) Multi-Link Device (MLD) negotiates with a non-AP legacy STA during admission control to agree on a maximum SI value, The apparatus according to claim 16. **Claim 20** When a conditional link can be used to execute a scheduled UL TXOP, the AP of the conditional link may send a poll frame to a non-EHT STA on the conditional link when a quality of service (QoS) conflict-free (CF) poll matches the trigger frame of an uplink (UL) TXOP initiated by the AP or the clear to send (CTS) frame of a UL TXOP initiated by a non-AP that is sent by the AP of a basic link belonging to the same soft AP MLD. The apparatus according to claim 16. **Claim 21** When a conditional link can be used for a scheduled DL TXOP, the AP of the conditional link of the same soft AP MLD sends a simultaneous downlink (DL) PPDU as if it were executed on a basic link. The apparatus according to claim 16. **Claim 22** When the AP of the conditional link does not have a DL PPDU to send, it sends a single DL NULL PPDU on the basic link with the NAV set as a simultaneous DL TXOP. The apparatus according to claim 21. **Claim 23** When the AP of the conditional link has a DL PPDU to send after sending a DL NULL PPDU, it sends a DL PPDU on the conditional link that matches the end of the DL PPDU on the basic link. The apparatus according to claim 22. **Claim 24** When a conditional link cannot be used for a scheduled UL / DL TXOP, the AP of the conditional link does not send a DL PPDU on the conditional link. The apparatus according to claim 23. **Claim 25** A wireless communication method in a network, (a) Performing multi-link operation (MLO) on a wireless local area network (WLAN) according to the IEEE 802 protocol configured to enable a legacy (non-EHT) device to establish a link connection on a conditional link, and performing wireless communication between a soft access point (AP) multi-link device (MLD) and other wireless stations (STAs) via a basic link and a conditional link; (b) The soft access point (AP) multi-link device (MLD) having an AP STA communicating via a basic link and an AP STA communicating via a conditional link; (c) the soft access point (AP) multi-link device (MLD) has a station management entity (SME) that cooperates with each other so that the AP STA on the basic link and the AP STA on the conditional link simultaneously process an extended distributed channel access (EDCA) transmission opportunity (TXOP) and a HCF control channel access (HCCA) TXOP via the basic link and the conditional link; (d) performing admission control on both the basic link and the conditional link, and proceeding with the setting and negotiation of a traffic stream (TS) in an EDCA TXOP, while the scheduling of the HCCA TXOP is based on the approved service period (SP) information in which the HCCA-approved access policies on both the basic link and the conditional link, obtained during the TS setting, are utilized; (e) an AP belonging to the same soft AP MLD schedules and allocates a synchronized uplink (UL) or downlink (DL) TXOP via both the basic link and the conditional link during the HCCA TXOP period; A method characterized by including the above.

26. A wireless communication method in a network, (a) When performing multi-link operation (MLO) on a wireless local area network (WLAN) according to the IEEE 802 protocol configured to enable a legacy (non-EHT) device to set up a link connection on a conditional link, wireless communication is performed between a soft access point (AP) multi-link device (MLD) and another wireless station (STA) via a basic link and a conditional link; (b) accessing the basic link based on an extended distributed channel access (EDCA) policy; (c) not being configured to operate at extremely high throughput (EHT), and thus accessing the conditional link based on an HCF control channel access (HCCA) policy for a legacy station that is a non-EHT STA; (d) accessing the conditional link through either EDCA or an HCCA-EDCA hybrid mode (HEMM); Since an access point (AP) accessing a conditional link of the same soft AP MLD and an AP accessing a basic link share a station management entity (SME), the access point (AP) accessing the conditional link recognizes that uplink / downlink (UL / DL) transmission is being performed on the basic link. Schedule a transmission opportunity (TXOP) as UL / DL transmission on the conditional link by the AP of the conditional link according to simultaneous UL / DL transmission on the basic link. During the scheduled TXOP on the conditional link, communicate one or more frames of a physical layer protocol data unit (PPDU) in a frame exchange sequence, and the start time and end time of each PPDU in the frame exchange sequence on the conditional link match the PPDU communicated on the basic link. A method characterized by including the above.

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