Communication apparatus and method

Abstract

A first communication device configured to communicate with one or more second communication devices, the first communication device comprising circuitry configured to detect collision detection indication information in data units received from the one or more second communication devices, the one or more second communication devices configured to transmit data units comprising collision detection indication information; determine, based on one or more received collision detection indication information, whether a collision or a reception failure has occurred; and transmit, if it is determined that a collision or a reception failure has occurred, collision resolution indication information indicating that a collision or a reception failure has occurred and / or indicating at least one of the one or more second communication devices that transmitted a data unit that caused the collision or experienced the reception failure.

Description

Technical Field

[0001] This disclosure relates to a first communication device and a second communication device, specifically for conflict detection and resolution. Background Technology

[0002] Enhanced Distributed Channel Access (EDCA) is the primary channel access protocol used in WLANs. This protocol is efficient when the number of stations (STAs; also known as non-AP STAs) contending for channel access is small, but it introduces very long channel access delays as the number of STAs increases. On the other hand, Triggered-Based (TB) channel access is more efficient when the number of STAs is large; however, it also introduces long delays when the access point (AP) is unaware of data traffic arriving at the STA. Despite using this protocol and implementing a backoff process, collisions and channel access delays can still occur when multiple STAs access the same channel.

[0003] The "Background Art" description provided herein is intended to present the general context of this disclosure. The work of the currently named inventors to the extent described in this Background Art section, and aspects of this description that may not have constituted prior art at the time of application, are unintentionally or impliedly acknowledged as prior art to this disclosure. Summary of the Invention

[0004] The objective is to reduce the probability of collisions and / or channel access delays, specifically in WLAN systems. Another objective is to provide a corresponding method, a corresponding computer program, and a non-transitory computer-readable recording medium storing a computer program product for implementing the method.

[0005] According to one aspect, a first communication device is provided, configured to communicate with one or more second communication devices, the first communication device including a circuit system configured to: - Detecting collision detection indication information in a data unit received from one or more second communication devices, wherein the one or more second communication devices are configured to transmit a data unit including the collision detection indication information; - Based on one or more received collision detection indication messages, determine whether a collision has occurred or reception has failed; and - If a conflict or reception failure is determined to have occurred, a conflict resolution instruction message is sent, which indicates that a conflict or reception failure has occurred and / or indicates that at least one of one or more second communication devices that caused the conflict or reception failure is sending data units.

[0006] According to another aspect, a second communication device is provided, configured to communicate with a first communication device, the first communication device being configured to communicate with one or more second communication devices, the second communication device including a circuit system configured to: - Sending data units including collision detection indication information; and - Receive a response or conflict resolution instruction from a first communication device to a transmitted data unit, the conflict resolution instruction indicating that a conflict or reception failure has occurred and / or indicating at least one of one or more second communication devices that transmitted the data unit that caused the conflict or reception failure.

[0007] According to other aspects, corresponding methods are provided, a computer program including a program means for causing the computer to perform the steps of the methods disclosed herein when the computer program is executed on a computer, and a non-transitory computer-readable recording medium storing a computer program product that causes the methods disclosed herein to be performed when executed by a processor.

[0008] The embodiments are defined in the dependent claims. It should be understood that the disclosed method, the disclosed computer program, and the disclosed computer-readable recording medium have similar and / or identical embodiments to the claimed apparatus and as defined in the dependent claims and / or disclosed herein.

[0009] One aspect of this disclosure utilizes collision detection indication information sent from a second communication device (which in one embodiment may be a STA, i.e., operating as an STA, but in another embodiment may be an AP, i.e., operating as an AP) to a first communication device (which in one embodiment may be an AP, i.e., operating as an AP, but in another embodiment may be a STA, i.e., operating as an STA). For example, the collision detection indication information may be sent as a physical layer (PHY) field in a data unit (e.g., a physical layer protocol data unit (PPDU)) in the form of a collision detection field (CoF). Therefore, collision resolution indication information, for example, in the form of a collision resolution field (CRF), indicates to one or more second communication devices that a collision or reception failure has occurred. Furthermore, it may instruct the second communication device that caused the collision or reception failure. This enables the second communication device to detect the collision and, optionally, take collision resolution measures, which may be indicated from the first communication device.

[0010] In this document, the term "collision" should be understood as an event in which two or more transmissions between different second communication devices or between a second communication device and another communication device (e.g., a conventional or interfering device that does not use collision detection indication information) completely or partially overlap in the time and / or frequency domains. For example, an event in which two or more STAs transmit PPDUs that completely or partially overlap in time represents a collision. For example, this may occur when devices simultaneously access the wireless medium after performing contention-based channel access or after receiving indication information from the AP that simultaneous transmission is permitted. Reception failure may be caused not only by the transmitting device but also by external factors affecting data unit reception, such as interference, channel conditions, etc.

[0011] Collision detection indication information should be broadly understood as indication information used in radio media where collisions or packet reception failures may occur. Some exemplary applications of collision detection indication information include one or more of the following: detecting and identifying collision STAs during distributed channel access and preemption scenarios, and identifying the sender of a data unit with failed packet reception. Collision detection indication information can be a signal inserted as a PHY field and composed of one or more OFDM symbols. These OFDM symbols can be truncated to form other periodic signals.

[0012] Contention-based channel access refers to a distributed channel access mechanism such as EDCA, in which a STA requiring access to the channel (or radio medium) performs Carrier Sense (CS) and / or Clear Channel Assessment (CCA) before transmitting to determine if the channel is busy. If the channel is busy, a backoff procedure is invoked, and channel access is performed when the backoff counter reaches zero.

[0013] The foregoing paragraphs have been provided by way of general description and are not intended to limit the scope of the following claims. The described embodiments, along with other advantages, will be best understood by referring to the following detailed description taken in conjunction with the accompanying drawings. Attached Figure Description

[0014] A more complete understanding of the present disclosure and its many accompanying advantages will be readily obtained when considered in conjunction with the accompanying drawings and by referring to the following detailed description, in which: Figure 1 A diagram is shown illustrating a communication scheme for conflict resolution using traditional EDCA behavior.

[0015] Figure 2 A diagram of the communication scheme is shown, illustrating an example of a conflict in frame-based preemption in a downlink scenario.

[0016] Figure 3A diagram illustrating a first embodiment of a communication scheme according to the present disclosure is shown, illustrating conflict resolution in the uplink via conflict detection indication information through trigger-based channel access.

[0017] Figure 4 A flowchart is shown, illustrating an implementation of the general process for conflict detection and resolution at the AP via the Conflict Detection Field (CoF).

[0018] Figure 5 A diagram illustrating a second embodiment of the communication scheme according to this disclosure is shown, illustrating conflict resolution in the uplink via CoF through shared TXOP operation.

[0019] Figure 6 A diagram illustrating a third embodiment of a communication scheme according to the present disclosure is shown, illustrating conflict resolution in the uplink via CoF through delayed channel access.

[0020] Figure 7 A diagram illustrating a fourth embodiment of the communication scheme according to the present disclosure shows a response indication message to a CRF to confirm CoF detection.

[0021] Figure 8 A flowchart is shown, illustrating an implementation of the general operation of a conflict STA.

[0022] Figure 9 A diagram illustrating a fifth embodiment of a communication scheme according to the present disclosure is shown, illustrating conflict resolution based on frame preemption using CoF.

[0023] Figure 10 A diagram illustrating a sixth embodiment of a communication scheme according to this disclosure is shown, illustrating AP contention prior to the transmission of the Collision Resolution Field (CRF).

[0024] Figure 11 A diagram is shown illustrating an implementation of the process for setting up the CoF operation.

[0025] Figure 12 A flowchart illustrating an embodiment of the first communication method according to this disclosure is shown.

[0026] Figure 13 A flowchart illustrating an embodiment of the second communication method according to this disclosure is shown.

[0027] Figure 14 A diagram illustrating a seventh embodiment of a communication scheme according to the present disclosure is shown, illustrating conflict resolution in the downlink.

[0028] Figure 15A diagram illustrating an eighth embodiment of a communication scheme according to the present disclosure is shown, illustrating conflict resolution in the uplink in the event of a conflict between communication devices of different basic service sets.

[0029] Figure 16 A diagram illustrating a ninth embodiment of a communication scheme according to the present disclosure is shown, illustrating conflict resolution in the downlink in the event of a conflict between communication devices of different basic service sets.

[0030] Figure 17 A diagram illustrating a tenth embodiment of a communication scheme according to the present disclosure is shown, illustrating conflict resolution in the uplink and downlink in the event of a conflict between communication devices of different basic service sets. Detailed Implementation

[0031] Referring now to the accompanying drawings, in which the same reference numerals denote the same or corresponding parts throughout several views. Figure 1 A diagram illustrating a communication scheme using collision resolution with EDCA (Electronic Contention Frame Inter-Frame Spacing) behavior is shown. A first communication device (AP in this embodiment) communicates with two second communication devices (stations STA1 and STA2 in this embodiment). Using EDCA is advantageous for low-latency applications because each STA can immediately begin competing for access to the channel when it has data to transmit, thus avoiding potential delays caused by waiting to be triggered by the AP. To avoid collisions, STAs using EDCA must invoke a backoff procedure when the channel is busy. Therefore, before transmitting, the STA must detect that the channel is idle for the duration of the Arbitration Inter-Frame Spacing (AIFS) and draw a random backoff counter from the interval [0, nCW], where nCW is an integer defining the size of the Contention Window (CW). The STA decrements its backoff counter for each specific time slot duration. When the backoff counter reaches zero, the STA is allowed to transmit. If the STA fails to transmit, for example due to a collision or temporary coverage loss, the STA must invoke the backoff procedure again, but this time it must double its CW, i.e., draw a new backoff counter from the interval [0, 2 × nCW - 1]. This is done to reduce the probability of conflict, but if Figure 1 As shown, it may cause even longer delays.

[0032] Conflicts may also occur in special scenarios based on frame preemption, where protocol changes have been introduced to provide channel access for low-latency applications. Figure 2 A diagram illustrating the communication scheme is shown, illustrating an example of a conflict in frame-based preemption in a downlink scenario. The AP initiates a transmission opportunity (TXOP) and adds an IFS gap (in the frame interval) between specific frames. Figure 2This is represented as a preemptive IFS (pIFS), which has a longer duration than the commonly used Short Interframe Space (SIFS). During these pIFS gaps, other STAs can send preemptive PPDUs (pPPDUs) carrying preemption indication information or data. Typically, a previous PPDU contains an indication to the STA with preemptive traffic notifying them of the upcoming pIFS gap. When more than one STA sends a pPPDU in the same pIFS gap, collisions may occur, such as... Figure 2 The diagram is for STA2 and STA3.

[0033] Because of the specific pIFS gaps that allow STAs to send pPPDUs, collisions may occur more frequently than in regular contention scenarios. This can lead to undesirable latency and reduce the efficiency of TXOPs. Frame-based preemption mechanisms already have inherent efficiency limitations because PPDUs need to have a limited duration to provide regular preemption gaps and support low-latency traffic constraints.

[0034] In many cases, frames are lost when collisions occur because they cannot be decoded, and it is only later that it is known which frame caused the collision. In the case of EDCA, the STA involved in the collision needs to wait for a predetermined timeout period without receiving a response, such as... Figure 1 As shown, they only realize their transmission has failed when they see this. Afterwards, the conflicting STAs compete again using a new backoff counter with doubled CW (in...). Figure 1 (AIFS is included during the timeout period). A collision can only be detected at the AP after one of the STAs has successfully sent a frame containing retransmission indication information.

[0035] exist Figure 2 In the frame-based preemption scenario shown, the AP needs to initiate a Buffered State Report (BSR) procedure to identify which STAs are experiencing conflicts. Furthermore, conflicts can occur during several pIFS intervals during TXOP. Therefore, using the BSR procedure to resolve conflicts in frame-based preemption leads to increased latency and reduced efficiency of data exchange during TXOP.

[0036] Figure 3A diagram illustrating a first embodiment of the communication scheme according to this disclosure shows collision resolution in the uplink via collision detection indication information through triggered (TB) channel access. According to this embodiment, collision detection fields (CoF) 10, 20, representing the embodiment of the collision detection indication information, are added as PHY fields to PPDUs 11, 21, which identify the STA that sent the PPDU. This enables the receiving STA (i.e., the AP in this embodiment) to detect collisions. CoF 10, 20 may, for example, be located after the conventional portion and at least one signaling field in the preamble of PPDUs 11, 21. In the example, CoF may be added to the first PPDU used to acquire the TXOP, which avoids further delays due to the exponential backoff process. CoF also enables the receiving STA (AP) to identify which STAs have collided, even if no other information (including SIG and data fields) can be decoded from the collided PPDUs 11, 21.

[0037] It should be noted that the AP is assumed to be the intended receiver of the CoF. If the AP identifies at least one of the STAs (STA1, STA2) that are colliding, it can modify the channel access to (at least partially) resolve the collision and reduce channel access delay. To this end, it can send a collision resolution indication message indicating that a collision or reception failure has occurred and / or indicating that at least one of the STAs that sent a PPDU that caused the collision or experienced the reception failure. In this embodiment, the Collision Resolution Field (CRF) 30 represents the collision resolution indication message. The receiver can typically determine that a detection failure has occurred when the likelihood value of the detection test does not reach a specific threshold within the selected detection window. This does not mean that the CoF is present or absent, but simply that the detection test did not detect the CoF. When this occurs, a second lower threshold can be used to trigger the initiation of detection window adjustment, or a continuous interference cancellation method can be employed.

[0038] To support the conflict resolution mechanism via CoF, the following can be considered. This can be done as part of the initialization or (re)configuration phase, or within the association process of each STA: CoF generation and distribution to all STAs: The AP should know all CoFs and their allocation to each STA. CoFs can be assigned to a single STA or a group of STAs. CoFs can also be used to indicate simplified traffic priority indicative of buffer status. For example, each STA can have two CoFs, each indicating whether the traffic buffer is below or above a specific level.

[0039] The configuration of the CoF to be used by each STA: CoF duration, CoF modulation parameters, and CoF sequence type.

[0040] The AP can set the definition of TB-PPDU or TXOP duration after collision detection.

[0041] In this implementation, an operating mode is provided in which the STA, which includes a CoF in its PPDU to request channel access, also configures these PPDUs to have equal durations. This ensures that the legacy signaling field (L-SIG) has equal content and increases its decoding reliability. In the event of a conflict, if the AP can extract the duration information from the L-SIG, it can adjust the duration of the scheduled TB-PPDU or TXOP.

[0042] Figure 4 A flowchart is shown illustrating an implementation of a general process 100 for conflict detection and resolution at the AP via CoF. The proposed mechanism for conflict detection and resolution using CoF is explained below.

[0043] In the implementation, there are two main assumptions regarding the format of the PPDU carrying the CoF: the PPDU may or may not contain a data field. In the first case, the PPDU with a data field carries an MPDU that includes Media Access Control (MAC) information in its header, such as the Transmit Address (TA) and Network Allocation Vector (NAV) setting information. Therefore, in the context of MAC information items explained below, it is assumed that the PPDU contains a data field. In the second case, the PPDU carrying the CoF contains only physical layer (PHY) information, and the resulting behavior is independent of the MAC information.

[0044] First, refer to Figure 4 This will explain the potential AP behavior. When energy (L-STF detection) is detected (this can be part of a carrier sense (CS) or idle channel assessment (CCA) process (step 101), the AP processes the PPDU as usual (decoding the preamble and data fields respectively; steps 102 and 105). Additionally, it can run (step 103) the CoF detection process (based on its configuration) in one or more of the following: for the first PPDU of a non-established TXOP, for PPDUs transmitted during a service period allowed for transmission by a specific STA, and for PPDUs within a TXOP where preemption is allowed (specifically, for PPDUs carrying preemption indication information or preemption data). Furthermore, it transmits (step 104) an indication of whether CoF was detected in a subsequent frame. This indication information can be a contention resolution / recovery frame (CRF) (…). Figure 3The part in section 30) will be explained in more detail below. This missing transmission can also be indicative information. If a CoF is detected, the STA ID or ID group is preferably also identified via the CoF. If the PPDU with the CoF also has a data field carrying a successfully decoded MPDU, the frame can also be included in the response PPDU.

[0045] The assessment of whether a collision has occurred can be performed as follows. A collision or packet decoding failure is detected via CoF under the following conditions (AP actions are as follows). Typically, CoF can be detected sequentially after preamble decoding and before data field decoding, or in parallel based on the results of the CS or CCA process. If a CoF is detected, one of the following may occur.

[0046] In the first case, the PPDU, including the data field, is correctly decoded (step 105). This PPDU contains at least one MPDU, where the sending STA identified by the sender address (TA) does not match an STA identified via CoF or a STA included in a group of STAs identified via CoF, as checked in step 106. In this case, a collision is detected (step 107), but a TXOP can be established for the STA that sent the correctly decoded MPDU. The AP can initiate the TXOP by sending a response frame to the STA (step 104) and allow the TXOP to be established. In this response frame, the AP can include channel access information to the STA identified via CoF. Further mechanisms are explained below.

[0047] In the second case, the PHY preamble decoding fails (step 108), or, if the PPDU contains a data field, all MPDUs in the PPDU fail to be successfully decoded (step 105). This situation does not necessarily mean a collision has occurred, as decoding failure could also be due to coverage interruption. However, since the CoF is detected, the transmitting STA can be identified (step 109), and the AP can decide whether to provide channel access (step 104) (the AP can use this as a collision resolution mechanism for granting channel access).

[0048] If at least two CoFs are detected in step 103, this is interpreted as a conflict, and the following mechanisms for conflict resolution (steps 109, 104, 110) explained below can be applied.

[0049] In the absence of collisions, it is assumed that the PPDU can be successfully decoded. The AP can determine (this is detected in step 111) whether the CoF was added via indication information in the PPDU preamble or via a previous negotiation phase, in which it was determined which STAs would use the CoF. If the CoF is not detected in step 111, and if the CoF was added in the PPDU, the AP can request (step 110) a CoF configuration change to the STA that sent the PPDU, or to all STAs in a group of STAs sharing the same CoF configuration, or to all STAs in the BSS. Furthermore, the AP can send a CoF report (step 110) in a separate frame to the STA identified by the TA in the decoded PPDU. This CoF report contains information about the detection value of the CoF (e.g., the likelihood ratio of the detection test, the detection probability, and / or the false alarm probability). It should be noted that the CoF is designed to be as robust as or more robust than the PHY preamble to ensure that the probability of a correctly decoded PPDU without a detected CoF should be very low. Assuming the PPDU contains a data field, if a CoF is detected and if the CoF identifies the same STA as the one identified by the TA of the MPDU carried in the PPDU, no further action is required regarding CoF processing, except (optionally) sending a CoF report to the sending STA to collect statistics on CoF detection performance. PPDU processing should continue as usual.

[0050] If at least one MPDU has been successfully decoded in step 105, and if the MPDU addresses the STA and the acknowledgment policy requires acknowledgment, then an acknowledgment is sent (step 112).

[0051] The following will explain the implementation of the collision resolution method according to this disclosure. If a collision or packet failure is detected via CoF, the AP will perform a predetermined inter-frame interval (IFS) after the medium is idle (e.g., after a collision occurs). Figure 3 The system (represented as IFS1) sends a Collision Resolution / Recovery Frame (CRF) to resolve a collision or to attempt to restore channel access if the attempt fails.

[0052] like Figure 3As shown, CRF can enable uplink TB channel access. The AP triggers (using CRF 30 itself and / or trigger frame TF 31) the STA identified in CoF 10, 20 to transmit data in TB-PPDU 12, 12a, 22, 22a, where the TB-PPDU duration can be determined by one of the following: the time duration of the collision (which can be estimated as the difference between the end of the collision (taken as the time when the radio medium is listened to as idle) and the start of the collision PPDU detection (e.g., from CS / CCA)), or a predetermined fixed value set by the AP or a previously negotiated value, or the duration information in the successfully decoded L-SIG (in the case that the collision PPDUs have equal lengths). Furthermore, the AP triggers the STA to collect BSR and continue uplink TB channel access.

[0053] like Figure 3 As shown, CRF 30 can act as a trigger frame, scheduling the first two PPDUs 12 and 22. Since the AP doesn't fully know how much traffic STA1 and STA2 need to send, the length of the first PPDUs 12 and 22 may be insufficient. Therefore, the second trigger 31 can be used to allow STA1 and STA2 to complete or continue their data transmission. Alternatively, CRF 30 can act as the trigger, but it first collects the buffer state from the STAs, which is the first PPDU 12 and 22, and then triggers the uplink data, i.e., the second PPDUs 12a and 22a.

[0054] In another implementation, the CRF can initiate a shared TXOP operation with one or more conflicting STAs or other STAs that need to send data. Figure 5 A diagram illustrating a second embodiment of the communication scheme according to this disclosure shows conflict resolution in the uplink via CoF through shared TXOP operations. Furthermore, TXOPs can be shared between downlink and / or peer-to-peer (P2P) traffic. The AP can assign priorities to one or more specific STAs, for example, based on Access Class (AC) or Traffic Identifier (TID).

[0055] In another implementation, the CRF can postpone, for example, channel access for a group of specific STAs with low-priority traffic. Figure 6 A diagram illustrating a third embodiment of the communication scheme according to this disclosure shows collision resolution in the uplink via CoF through delayed channel access. The AP may request STA2 not to double CW 24, 25 compared to the original CW 23 to avoid additional delays due to increased exponential backoff.

[0056] exist Figure 6In the example shown, STA2 is deferred in favor of STA1, giving STA1 priority. The next TXOP32 is initiated by the AP because it typically has a shorter backoff counter. At this point, STA2 initiates contention for channel access using a new backoff counter 24 that is not doubled. This modification allows STA2 to avoid long waiting times before transmitting. For example, in this scenario, STA1 might have data arriving during the AP's TXOP 32. Without this modification to the length of CW 24, STA1 would likely win the contention before STA2.

[0057] In another implementation, the AP can move frame switching to another link.

[0058] In addition, a CRF can also indicate one or more of the following: If other STAs are able to extract NAV information from the conflicting PPDU, reset the NAV for all other STAs, assuming the conflicting PPDU contains the data field carrying the MPDU; The STAs involved in the collision (or failed transmission) extracted from the detected CoF, as well as indications of whether these STAs are allowed to extract new backoff counters in the case of doubling the CW, indications of whether one or more of these STAs can use other EDCA parameters (e.g., reduced AIFS), and / or indications of whether one or more of these STAs will be triggered in the upcoming TXOP. The collision STAs that are not detected by the CoF (the AP does not know who they are) are instructed to be able to draw a new backoff counter without doubling the CW, which is only allowed if the collision is (at least partially) resolved, meaning that the CRF grants channel access to at least one collision STA; Instruct delayed and / or unscheduled STAs to start their TXOPs with mandatory CoF using only short frames, and also to use a more robust CoF configuration.

[0059] The expected response to a CRF frame can be configured as follows. Depending on the conflict resolution mechanism triggered by the CRF, the STA can reply with a PPDU containing data, or as follows: Figure 6 No response as shown, or as Figure 7 The response shown is a short response. Figure 7 A diagram illustrating a fourth embodiment of the communication scheme according to the present disclosure shows a response indication message to a CRF to confirm CoF detection.

[0060] In very rare cases, it may happen that the CoF detected by the AP is incorrect and an incorrect STA is identified as a conflicting STA. For example, in Figure 7 In the example shown, STA3 is identified as a conflicting STA, but only STA1 and STA2 are conflicting. To address this situation, the AP can request in CRF 30 that all STAs identified as conflicting always respond with indication information indicating whether they are involved in the conflict. This request can be included in CRF 30 or added to an additional response field 36 of that CRF. This response indication information can be in a separate short PPDU, such as... Figure 7 The response frames R16 and R46 are shown in the middle.

[0061] Collision STAs not identified in CRF 30 can be allowed to re-pump the backoff counter without doubling the CW, or optionally utilize a short AIFS. Figure 7 In the example, this mechanism allows STA2 to have shorter contention (compared to doubled CW), avoiding further delays (e.g., otherwise STA3 would gain channel access before STA2).

[0062] If there is no response to the CRF, the AP should fall back to standard EDCA rules, such as initiating a new backoff procedure to schedule the conflicting STA. For example, if the STA addressed in CRF 30 suffers a temporary interruption (e.g., shadowing effects or external interference prevents it from decoding the CRF), no response may occur.

[0063] Now refer to Figure 8 Explain the behavior of conflicting STAs. Figure 8 A flowchart is shown illustrating an implementation of the general operation 200 for a conflicting STA. Initially, the STA and AP agree on the use and configuration of the CoF. Upon startup, the STA either competes for channel access via EDCA (step 201) or acquires channel access during a preemptive pIFS interval (step 202). In step 203, the STA adds the CoF to the PPDU in one or more of the following cases: for the first PPDU of a non-established TXOP, for a PPDU transmitted during a service period in which a particular STA is allowed to transmit, or for a PPDU within a TXOP that allows preemptive operation (e.g., ...). Figure 9 As shown, Figure 9 A diagram illustrating a fifth embodiment of a communication scheme according to the present disclosure is shown, which illustrates frame-based conflict resolution for preemption using CoF, specifically for a PPDU carrying preemption indication information or preemption data.

[0064] If the colliding STA receives a response frame as normal (checked in step 204), and the STA receives an indication that the CoF was successfully detected (step 205), this means there was no collision and CoF detection worked as expected, therefore no further action is needed; that is, frame switching can continue within the TXOP (step 206). If the colliding STA receives an indication of CoF failure (or missing CoF information), this means the PPDU was correctly decoded at the receiver, but the CoF was not detected. The colliding STA can then modify the CoF configuration upon request from the AP (step 207).

[0065] If a CRF is received (step 208) and it conveys the action addressed to the conflicting STA, the conflicting STA follows the instructions of the AP (step 209), such as responding to the TF, responding to a frame of scheduled shared TXOP operation (e.g., MU-RTS), delaying channel access by extracting a new backoff counter and (if permitted) not doubling the CW and optionally modifying the AIFS before competing again (this can be done in the same channel after the current TXOP ends, or in a separate link if indicated in the CRF), or modifying the EDCA parameters, such as not doubling the CW or changing the AIFS duration.

[0066] If a CRF is received but it does not contain any action or information regarding the STA involved in the collision (step 210), this means the AP is unaware that the STA is also part of the collision. If permitted (indicated in the CRF), the STA may not increment its CW, extract a new backoff counter, and optionally change the EDCA parameters as indicated in the CRF. If indicated in the CRF, a short frame with a mandatory CoF and a more robust CoF configuration can be used in the next channel access attempt.

[0067] If no response frame is received within the predetermined timeout period, the STA should fall back to standard backoff (2 × CW - 1) operation (step 201 or 202). The timeout period value is set based on the expected duration required for the response to be received. This may include AIFS, receiver PHY delay, and the length of the response frame.

[0068] For frame-based preemption scenarios, conflict resolution examples are provided in... Figure 9 As shown, STA2 and STA3 are conflicting STAs. In this case, the STAs with preemptive traffic (STA2, STA3) should include CoF 20, 40 in PPDUs 27, 47 carrying preemptive indication information or data. This allows the AP to identify which STAs are involved in the conflict and initiate a conflict resolution mechanism from the mechanisms defined above (as explained for conflict resolution). Figure 9In the example shown, CRF 30 triggers a conflict STA to reduce latency caused by the additional BSR process.

[0069] Normally, if a conflict exists on the CRF, all STAs should fall back to traditional behavior, double the CW, and wait for the AIFS before the countdown backoff counter.

[0070] In the IEEE 802.11 standard, a TXOP is typically established through the successful exchange of two PPDUs, where the STA initiating the exchange obtains channel access via EDCA. To comply with standard operation, one of the following rules can be implemented: In the event of a collision detected via CoF detection, the AP can perform a backoff procedure before sending a CRF, such as... Figure 10 As shown, Figure 10 A diagram illustrating a sixth embodiment of the communication scheme according to this disclosure is shown, illustrating AP contention 33 prior to the transmission of CRF 30. In the event that a collision is detected at the AP via CoF detection, the AP can initiate TXOP without performing a backoff procedure, for example, as... Figure 5 As shown. Furthermore, at least one frame in the TXOP should be scheduled to resolve collisions and allow at least one conflicting STA to transmit data (e.g., the TF and / or CRF should schedule the conflicting STA). The duration of the TXOP containing the transmission of the conflicting STA can be set to a predetermined duration.

[0071] As described above, the AP should determine the STA ID based on CoF detection. To achieve this, the AP can correlate the received signal with all possible CoF signals and select those whose likelihood values ​​are above a predetermined threshold. If the number of possible CoFs is too large (e.g., more than hundreds), this operation can become highly complex. To reduce complexity, several STAs can be grouped into a single CoF signal, and after detection, the AP can trigger the STAs corresponding to that group to identify the transmitting STA.

[0072] In the operational implementation, each CoF signal can identify a different transmitting STA, necessitating the generation of several different CoF signals. The cross-correlation between the CoF signals determines the detection performance at the receiver; lower cross-correlation implies higher detection reliability. Furthermore, conflict transmissions are typically not synchronous, requiring the cross-correlation between CoF signals to be low even with time and frequency offsets.

[0073] There are two main design parameters for generating CoF signals: the duration of the CoF signal and the number of different CoF signals to be generated, denoted as Ncof.

[0074] The duration of the CoF signal determines the number of sampling points it has (e.g., based on the PPDU bandwidth). More CoF sampling points result in higher detection reliability. Furthermore, a larger number of CoF sampling points makes it easier to separate Ncof signals; specifically, it is desirable for the number of CoF sampling points to be greater than or equal to Ncof.

[0075] Figure 11 A diagram is shown illustrating an implementation of the process 300 for setting up CoF operation. This process involves defining key parameters (e.g., number of STAs), CoF configuration, signal generation, and distribution.

[0076] The general process for generating and distributing CoF signals can be as follows. In block 302, the duration of the CoF signal within the PPDU is defined. Several durations can be defined to map to several CoF configurations. Therefore, it is advantageous to define the duration with a predetermined step size. For example, for a 20MHz bandwidth, 4µs is a practical step size containing 80 sampling points, which corresponds to one OFDM symbol with an FFT size of NFFT = 64 plus a guard interval (GI) of 16 sampling points.

[0077] In box 301, the number of different CoF signals to be generated is defined, denoted as Ncof. They can be calculated as follows: Ncof=(ceil(N_contending_STAs / N_STA_groups)×N_ind_per_STA) Where ceil() represents the rounding operation to the nearest largest integer value. N_contending_STAs is the number of STAs competing for channel access. When using CoF to provide more information than STA identification, N_ind_per_STA is the amount of indication information per STA. This additional information includes, for example, buffer status indication information for each STA (each STA may have, for example, two CoFs, one indicating short packets below a certain threshold and the other indicating larger packets above that threshold) and the priority level of the data to be transmitted, which can be defined based on TID, AC, or Flow Classification Service (SCS) characteristics. N_STA_groups is the number of groups of STAs grouped together for shared CoF allocation.

[0078] In box 303, the CoF signal is generated. Specifically, the complex-valued sequence is generated by one of the following: A binary sequence is created and modulated using PSK modulation (e.g., BPSK or QPSK) to obtain a complex-valued sequence with low cross-correlation. The binary sequence can be a common sequence with low cross-correlation, such as a Gold sequence, or a randomly generated sequence, wherein the PSK-modulated complex-valued sequence has a cross-correlation below a predetermined threshold.

[0079] Create complex-valued sequences based on DFT or Hadamard matrices.

[0080] The bits corresponding to each STA ID are encoded using robust channel coding operations (e.g., BCC with a code rate of 1 / 2 or 1 / 3), and the encoded bits are modulated using robust modulation (e.g., BPSK) to create a complex-valued sequence.

[0081] In block 304, the complex-valued sequence is modulated into the waveform to be transmitted. This can be done using a time-domain waveform, where the complex-valued sequence can be phase-shifted and transmitted using pulse amplitude modulation (PAM). Alternatively, this can be done using an OFDM waveform, where the complex-valued sequence can be phase-shifted and mapped onto subcarriers in an OFDM grid, which are then modulated into OFDM symbols and transmitted.

[0082] In box 305, CoF signals are assigned to STAs. When each STA has several different CoF signals assigned to it (e.g., each with additional indication information), the signal with the greater cross-correlation with its own and the CoF signals assigned to other STAs is selected. When more than one STA is identified by different CoF signals, STAs unlikely to simultaneously compete for channel access (e.g., if they have non-overlapping regular activity intervals) are grouped together.

[0083] In box 306, information is exchanged between the AP and all STAs in the BSS, so that each STA knows which CoF signal to use (and what additional indication information can be conveyed), and the AP knows all CoFs corresponding to each STA. For the AP, all CoF signals and their STA assignments, plus the additional indication information, should be known. CoF signal generation can be done centrally at the AP, which then sends indication information to each STA regarding how to generate its own CoF signal or the CoF signal itself.

[0084] Based on the general process of creating a CoF signal described above, it may be desirable to have several CoF configurations available to dynamically balance reliability, signaling overhead, and complexity. Different CoF configurations can be obtained by changing one or more of the following parameters: the duration and / or length of the CoF signal, the modulation parameters (modulation and coding scheme when the coded STA ID is used to generate the CoF signal; FFT size, guard interval, and subcarrier mapping used in the case of OFDM modulation), and the sequence type, such as one of the low cross-correlation pseudo-random sequence types (e.g., Gold, Kasami, JPL) and orthogonal sequences (DFT or Hadamard).

[0085] Figure 12 A flowchart illustrating an embodiment of a first communication method 400 according to a first communication device (AP) of the present disclosure is shown. This first communication method can be executed by a circuit system or a programming computer of a separate unit or processor of the first communication device. In a first step 401, collision detection indication information is detected in data units received from one or more second communication devices (STAs) configured to transmit data units including collision detection indication information. In a second step 402, based on one or more received collision detection indication messages, it is determined whether a collision or reception failure has occurred. In a third step 403, if a collision or reception failure is determined to have occurred, collision resolution indication information is transmitted, indicating that a collision or reception failure has occurred and / or indicating at least one of the one or more second communication devices that transmitted the data unit that caused the collision or experienced the reception failure.

[0086] Figure 13 A flowchart illustrating an embodiment of a second communication method 500 according to the present disclosure for a second communication device (any of the STAs) is shown. This second communication method can be executed by a programming computer of the circuitry or a separate unit or processor of the second communication device. In a first step 501, a data unit including collision detection indication information is transmitted. In a second step 502, a response to the transmitted data unit is received from the first communication device, or collision resolution indication information is received indicating that a collision or reception failure has occurred and / or indicating that at least one of the one or more second communication devices transmitted the data unit that caused the collision or reception failure.

[0087] Reference Figures 3 to 11In the described embodiments, a first communication device is configured to operate as an AP, and one or more second communication devices are configured to operate as a STA / non-AP STA. These embodiments relate to uplink (UL) scenarios. Hereinafter, embodiments of this disclosure relating to downlink (DL) scenarios will be presented, wherein a first communication device is configured to operate as a STA / non-AP STA, a second communication device is configured to operate as an AP, and additional second communication devices are also configured as STA / non-AP STA. Furthermore, embodiments of this disclosure relating to hybrid UL / DL scenarios will be presented, wherein conflicts occur between communication devices of different (overlapping) Basic Service Sets ((O)BSS).

[0088] Figure 14 A diagram illustrating a seventh embodiment of the communication scheme according to this disclosure shows collision resolution in the downlink. The AP includes a Collision Detection Field (CoF) 50 in its PPDU 51, for example, in the PPDU preamble. CoF 50 corresponds to the CoF assigned to the receiving STA or the collision responder (the STA assumed to reply with CRF), in this case STA2 (the first communication device in this embodiment). The non-AP STA (STA2) only replies with CRF if it detects a CoF assigned to itself. Since this particular CoF 50 can only be used by the non-AP STA2, this implicitly means that the AP sent it (i.e., it implicitly identifies the AP as the sender). The non-AP STA2 is assumed to reply with CRF 60. A colliding non-AP STA1 can send another CoF 70 in PPDU 71, which can be configured and / or contain information as explained above for CoF 10.

[0089] According to this conflict resolution mechanism, CRF 60 notifies all other STAs (STA1, STA3...STAN, representing other second communication devices in this embodiment, and APs) of a DL conflict or packet failure. Therefore, all non-AP STAs (STA1, STA3...STAN) postpone channel access for a fixed period. Conflicting STAs can compete again after the current DL TXOP ends without increasing the contention window (CW).

[0090] An AP acquires channel access and initiates its TXOP. An AP can initiate a TXOP by triggering a buffer status report from a conflicting STA. CRF 60 can also include identification of other conflicting STAs, allowing the AP to trigger them or initiate a shared TXOP. This can increase complexity at non-AP STAs, as it requires detecting more CoFs than just those used to identify itself.

[0091] Figure 15 A diagram illustrating an eighth embodiment of the communication scheme according to this disclosure shows conflict resolution in the uplink in the event of a conflict between communication devices in different Basic Service Sets (BSSs). In this embodiment, AP1 and AP2 represent first communication devices, and STA represents a second communication device. The CoF design may be limited such that communication devices in different BSSs may use the same CoF to identify different non-AP STAs. To overcome this potential problem, service set information indicating the BSS to which the device belongs can be included within or added to the CoF. Figure 15 In this context, CoF(1,1) 72 sent by STA1 (which exists in BSS1) identifies STA1 as the sender of CoF 72 and BSS1 as the BSS to which STA1 belongs. CoF(3,2) 82 sent by STA3 (which exists in BSS2 and is the OBSS of BSS1) identifies STA3 as the sender of CoF 82 and BSS2 as the BSS to which STA3 belongs. CoF 72 and CoF 82 can be sent in the corresponding PPDUs 73 and 83.

[0092] For non-AP STAs, CoF 72 and 82 identify themselves as the sender and their respective BSS. For AP STAs, CoF 72 and 82 identify the target receiver within their BSS and its respective BSS. (See above for reference.) Figure 14 As explained, when the AP uses the CoF assigned to the receiving STA itself, the receiving STA implicitly understands that the AP sent that CoF.

[0093] exist Figure 15 The document specifically illustrates a UL-to-UL scenario, where a conflict exists between STA1 (of BSS1) and STA3 (of BSS2), also referred to herein as an OBSS conflict (i.e., the two communication devices belong to different BSSs). To resolve this conflict, a method is proposed that allows the AP to identify OBSS conflicts. If an OBSS conflict is detected (e.g., CoF 82 identifies BSS2 through an evaluation of CoF 82 by AP1), one or more of the following steps can be taken.

[0094] As a first option, a designated AP can respond with CRF 52. The AP priority order can be fixed (e.g., AP1>AP2>AP3, ...), meaning the order in which APs can send messages can be set, and only the highest priority AP can then respond with CRF. Furthermore, this order can be changed in a polling manner at regular intervals to avoid fairness issues. As a second option, short backoff can be implemented, allowing only APs to contend for channel access, which reduces the likelihood of CRF collisions. This short backoff can be accomplished using EDCA parameters different from those used during regular EDCA operation. If a CRF collision occurs, a fallback to Enhanced Distributed Channel Access (EDCA) can be implemented (for non-AP STAs, this means waiting a specific amount of time (e.g., EIFS) and initiating a backoff process with an increased CW when they want to access the channel again; for APs, this means they will not receive a CRF response until the timer expires during the timeout period, meaning collision resolution fails and they need to wait a certain amount of time and initiate another backoff process when they need to access the channel). As a third option, a BSS-specific short wait time (e.g., inter-frame interval, IFS) can be set, which is different. This establishes a priority order among APs, reducing the likelihood of CRF conflicts. IFS can be changed in a round-robin fashion at regular intervals to avoid fairness issues.

[0095] Therefore, CRF 52 indicates an OBSS collision and identifies the STA (here, STA1) that should initiate a TXOP, while other STAs should postpone channel access and the initiation of a TXOP. Optionally, CRF 92 (which may be a copy of CRF 52) can be broadcast by AP2 to avoid further OBSS collisions.

[0096] Figure 16 A diagram illustrating a ninth embodiment of a communication scheme according to this disclosure is shown, illustrating conflict resolution in the downlink in the event of conflicts between communication devices in different basic service sets. In this embodiment, STA1 and STA3 represent first communication devices, and AP and other STAs represent second communication devices.

[0097] exist Figure 16 The diagram illustrates a DL-to-DL scenario, where a conflict exists between AP1 (of BSS1) and AP2 (of BSS2), also known as an OBSS conflict. To resolve this conflict, non-AP STAs (e.g., STA1, STA3) detect CoF 50, 90 in PPDU 51, 91 and identify their BSS and themselves as the intended receivers. If a non-AP STA (STA1, STA3) identifies an OBSS conflict, the above reference can be used before sending CRF 74, 84. Figure 15The method described. Otherwise, CRF 74, 84 can be sent using CoF 75, 85, which identifies its corresponding BSS. The AP can then identify OBSS conflicts and follow the above reference. Figure 15 The options described.

[0098] Figure 17 A diagram illustrating a tenth embodiment of a communication scheme according to this disclosure is shown, illustrating conflict resolution in the uplink and downlink in the event of conflicts between communication devices in different basic service sets. In this embodiment, STA1 and AP2 represent first communication devices, and AP1 and other STAs represent second communication devices.

[0099] exist Figure 17 The example illustrates the UL vs. DL scenario, where a conflict exists between AP1 (BSS1) and STA3 (BSS2), also known as an OBSS conflict. If AP2 identifies an OBSS conflict with AP1, AP2 will not respond to it using CRF. To resolve this conflict, the non-AP STA (STA1) correctly detects CoF 50 and identifies its BSS and itself as the intended receiver. If a non-AP STA identifies an OBSS conflict, the above reference can be used. Figure 15 The method described. Otherwise, it can send CRF 74, where CoF 75 identifies itself as the sender and its corresponding BSS. AP1 then decodes CRF 74, and if it does not identify another CoF within the CRF, meaning there is no CRF collision, it can initiate its TXOP.

[0100] Therefore, according to the reference Figures 14 to 17 In the described implementation, the collision indication information may include an implicit receiver identifier for DL ​​(Deep Flow) cases and / or a BSS (Best Support Message) identifier for OBSS (Overlapping Message) cases. The STA receiving the collision indication information that identifies itself responds with a CRF (Content Requested) that identifies the collision as DL. If the STA receiving the collision indication information identifies its BSS and another BSS from an overlapping transmission, the CRF may indicate that an OBSS collision has occurred. Typically, the CRF may include the collision indication information in its preamble, specifically if it is a non-AP (Area-of-Service) STA.

[0101] In summary, according to embodiments of this disclosure, a communication device, such as an AP, can detect PHY indication information in a received PPDU and extract information identifying the transmitting device for each transmitted PPDU, determine whether a collision or packet reception failure has occurred between PPDUs, and, if a collision or packet failure has occurred, send indication information to the transmitting STA and other STAs, indicating which STAs were involved in the collision or packet failure and / or identified in the detected PHY indication information. The transmitting / collision communication device, such as an STA, may include PHY indication information, including information identifying the STA as the sender, at least in the first PPDU transmitted to establish a TXOP, or during a service period when a particular STA is allowed to transmit, or during a predetermined IFS gap within an established TXOP that allows preemption of data transmission. The PHY indication information receives the indication information from the AP and determines whether it was involved in a collision or packet failure when transmitting the PPDU.

[0102] The device can be implemented by corresponding units or circuit systems that perform the functions of the device, such as processors, processing circuit systems, computers, dedicated hardware, etc. Alternatively, common units or circuit systems, such as common processors or computers, can implement the various functions of the device, or individual units or elements that together represent the circuit system can be used.

[0103] Therefore, the foregoing discussion discloses and describes exemplary embodiments of this disclosure only. As those skilled in the art will understand, this disclosure may be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the disclosure of this disclosure is intended to be illustrative and not to limit the scope of this disclosure and the other claims. This disclosure, including any readily identifiable variations taught herein, partially defines the scope of the foregoing claim terms so that no inventive subject matter is donated to the public.

[0104] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude a plurality. A single element or other unit may fulfill the function of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used advantageously.

[0105] Since embodiments of this disclosure have been described as being implemented by a data processing apparatus that is at least partially controlled by software, it will be appreciated that non-transitory machine-readable media carrying such software, such as optical discs, magnetic disks, semiconductor memories, etc., are also considered to represent embodiments of this disclosure. Furthermore, such software may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunications systems.

[0106] The elements of the disclosed devices, apparatuses, and systems can be implemented by corresponding hardware and / or software elements, such as appropriate circuits or circuit systems. A circuit is a structural assembly of electronic components, including conventional circuit elements, including application-specific integrated circuits (ASICs), standard integrated circuits, application-specific standard products, and field-programmable gate arrays (FPGAs). Furthermore, circuits include central processing units, graphics processing units, and microprocessors programmed or configured according to software code. Circuits do not include pure software, although they include the aforementioned hardware that executes the software. A circuit or circuit system can be implemented by a single device or unit, multiple devices or units, a chipset, or a processor.

[0107] The following are alternative implementations of the disclosed subject matter: 1. A first communication device configured to communicate with one or more second communication devices, the first communication device including a circuit system configured to: - Detecting collision detection indication information in a data unit received from one or more second communication devices, wherein the one or more second communication devices are configured to transmit a data unit including the collision detection indication information; - Based on one or more received collision detection indication messages, determine whether a collision has occurred or reception has failed; and - If a conflict or reception failure is determined to have occurred, a conflict resolution instruction message is sent, which indicates that a conflict or reception failure has occurred and / or indicates that at least one of one or more second communication devices has sent data units that caused the conflict or reception failure.

[0108] 2. According to the first communication device of Embodiment 1, The circuit system is configured to detect collision detection indication information in data units received from one or more second communication devices after performing contention-based channel access, during a predetermined service period, or during a predetermined time interval within an established transmission opportunity, wherein the one or more second communication devices are configured to transmit data units including collision detection indication information.

[0109] 3. The first communication device according to any one of embodiments 1 to 2, The circuit system is configured to acquire and / or instruct and / or exchange with one or more second communication devices information indicating one or more of the following: - The distribution of collision detection indication information to one or more second communication devices; - Should the collision detection indication information be included in subsequent data units sent by one or more second communication devices? -Whether the subsequent data unit can initiate a transmission opportunity; - Does the collision detection indication information indicate the traffic priority and / or buffer status of the corresponding second communication device? - Configuration of conflict detection indication information; and - The maximum length of the data unit including collision detection indication information.

[0110] 4. According to the first communication device of embodiment 3, The circuit system is configured to acquire and / or indicate and / or exchange configuration information with one or more second communication devices indicating collision detection indication information, the configuration of which includes one or more of the following: duration, modulation parameters, sequence type, subcarrier index allocation, time / symbol sequence index allocation, definition of trigger-based data units and / or transmission opportunity duration that the first communication device can set after the detection of a collision or reception failure.

[0111] 5. The first communication device according to any one of embodiments 1 to 4, The circuit system is configured to determine whether a collision or reception failure has occurred based on one or more received collision detection indications by detecting one or more of the following: - The transmission information that indicates the second communication device as the sender of the collision detection indication information included in the collision detection indication information does not match the transmission information included in the data unit received and correctly decoded by the first communication device; - At least one collision detection indication was detected, and decoding of the preamble and / or data field of one or more data units failed; - Receive at least two collision detection indication messages from different second communication devices.

[0112] 6. The first communication device according to any one of embodiments 1 to 5, The circuit system is configured to perform one or more of the following actions if no collision detection indication information is detected from the second communication device, but the first communication device knows that the second communication device should have sent the collision detection indication information: - Send a request to one or more second communication devices to change the configuration of the collision detection indication information; and - Send a collision detection report to one or more second communication devices, the collision detection report including information about the detection value of the collision detection indication information.

[0113] 7. The first communication device according to any one of embodiments 1 to 6, The circuit system is configured to send a conflict resolution indication message if a collision occurs or reception fails. This conflict resolution indication message is configured to notify at least one or more of the following to one or more second communication devices indicated by the received conflict detection indication message: - Enable trigger-based channel access; - Schedule the transmission of one or more second communication devices; -Initiate a shared TXOP operation with the first communication device; - Delay channel access; - Move data exchange to another link; - Modify network assignment vector settings; - Send a response indicating whether the second communication device is involved in the conflict; - Indicates whether an OBSS conflict has occurred, i.e., a conflict with the transmission of the first or second communication device of the overlapping BSS (OBSS); - Indicates whether the second communication device is allowed to extract a new backoff counter and / or whether the second communication device is allowed to extract a new backoff counter without increasing the contention window; - Indicates whether the second communication device can use other channel access parameters; - Indicates whether the second communication device will be triggered in the upcoming transmission opportunity; and - Indicates whether the second communication device is able to initiate a transmission opportunity with mandatory collision detection indication information using only short frames and / or use a more robust configuration with collision detection indication information.

[0114] 8. The first communication device according to any one of embodiments 1 to 7, The circuit system is configured to send a collision resolution instruction in a broadcast data unit if a collision or reception failure occurs. This broadcast data unit is configured to notify one or more of the following from a second communication device that previously transmitted the data unit: - Modify network assignment vector settings; - Delay channel access; - Whether the second communication device is allowed to extract a new backoff counter and / or whether the second communication device is allowed to extract a new backoff counter without increasing the contention window; - Indicates whether the second communication device can use other channel access parameters; and - Indicates whether the second communication device is able to initiate a transmission opportunity with mandatory collision detection indication information using only short frames and / or use a more robust configuration with collision detection indication information.

[0115] 9. A first communication device according to any one of embodiments 1 to 8, The circuit system is configured as follows: - Perform the backoff procedure before transmitting conflict resolution instructions; or - When the wireless medium is identified as idle after a collision or packet error has been determined, a transmission opportunity is initiated without performing a backoff process by sending a data unit carrying a collision resolution indication message, which schedules the transmission of the data unit of the second communication device; or - Seize existing transmission opportunities to schedule the transmission of data units of the second communication device after the transmission of conflict resolution instruction information from the first communication device.

[0116] 10. A first communication device according to any one of embodiments 1 to 9, The circuit system is configured to generate and / or indicate collision detection indication information to one or more second communication devices via one or more of the following configurations: - Define the duration of the conflict detection indication information within the data unit; - Define the number of different conflict detection indication messages; - Create a sequence of complex values ​​representing or included in collision detection indication information; - Modulate the complex-valued sequence into a waveform to be transmitted as a collision detection indication message; - Assign one or more collision detection indication messages to one or more second communication devices; and - Notify the second communication device associated with the first communication device of the allocation of one or more collision detection indication messages to one or more second communication devices.

[0117] 11. A second communication device configured to communicate with a first communication device, the first communication device being configured to communicate with one or more second communication devices, the second communication device including a circuit system configured to: - Sending data units including collision detection indication information; and - Receive a response or conflict resolution instruction from a first communication device to a transmitted data unit, the conflict resolution instruction indicating that a conflict or reception failure has occurred and / or indicating at least one of one or more second communication devices that transmitted the data unit that caused the conflict or reception failure.

[0118] 12. The second communication device according to embodiment 11, The circuit system is configured to receive conflict resolution instruction information from a first communication device, which identifies a second communication device as a participant in a conflict as determined by the first communication device by detecting conflict detection instruction information.

[0119] 13. The second communication device according to embodiment 11 or 12, Specifically, the circuit system is configured to include collision detection indication information in the preamble of the data unit, specifically in the physical layer preamble of the physical layer protocol data unit.

[0120] 14. The second communication device according to any one of embodiments 11 to 13, The circuit system is configured to transmit data units including collision detection indication information after performing contention-based channel access, or during a predetermined service period, or during a predetermined time interval within an established transmission opportunity, and / or is configured to include the collision detection indication information in one or more of the following: - The first data unit transmitted after performing contention-based channel access; - Data units transmitted during service periods when one or more second communication devices are permitted to transmit; and - A data unit that carries preemption indication information and / or preemption data.

[0121] 15. A second communication device according to any one of embodiments 11 to 14, The circuit system is configured to include one or more of the following in the collision detection indication information: - The second communication device is designated as the sender of the collision detection indication information; - Designating the first communication device as the recipient of the conflict detection information and / or designating it as the target information for the device to resolve the conflict; and - Service set information indicating the basic service set of the second communication device.

[0122] 16. A second communication device according to any one of embodiments 11 to 15, The circuit system is configured to perform one or more of the following in response to a received conflict resolution instruction: - Sending a response and / or a data unit containing data; - Trigger-based channel access is performed by sending trigger-based data units; - Send traffic according to the received schedule; -Initiate a shared TXOP operation with the first communication device; - Delay channel access; - Move data exchange to another link; - Modify network assignment vector settings; - Send a response indicating whether the second communication device is involved in the conflict; - Extract a new retreat counter; - If the second communication device is not indicated or the channel access of the second communication device is delayed in the collision detection indication information, a new backoff counter is extracted without increasing the contention window; - Use other channel access parameters; - Only use short frames to initiate transmission opportunities with mandatory collision detection indication information; and - A more robust configuration using conflict detection indication information.

[0123] 17. A second communication device according to any one of embodiments 11 to 16, The circuit system is configured to modulate one or more complex-valued sequences into waveforms to be transmitted as collision detection indication information.

[0124] 18. A first communication method for a first communication device, the first communication device being configured to communicate with one or more second communication devices, the first communication method comprising: - Detecting collision detection indication information in a data unit received from one or more second communication devices, wherein the one or more second communication devices are configured to transmit a data unit including the collision detection indication information; - Based on one or more received collision detection indication messages, determine whether a collision has occurred or reception has failed; and - If a conflict or reception failure is determined to have occurred, a conflict resolution instruction message is sent, which indicates that a conflict or reception failure has occurred and / or indicates that at least one of one or more second communication devices that caused the conflict or reception failure is sending data units.

[0125] 19. A second communication method for a second communication device, the second communication device being configured to communicate with a first communication device, the first communication device being configured to communicate with one or more second communication devices, the second communication method comprising: - Sending data units including collision detection indication information; and - Receive a response or conflict resolution instruction from a first communication device to a transmitted data unit, the conflict resolution instruction indicating that a conflict or reception failure has occurred and / or indicating at least one of one or more second communication devices that transmitted the data unit that caused the conflict or reception failure.

[0126] 20. A non-transitory computer-readable recording medium storing a computer program product that, when executed by a processor, causes the execution of a method according to embodiment 18 or 19.

[0127] 21. A computer program including program code means for causing the computer to perform the steps of the method according to embodiment 18 or 19 when the computer program is executed on a computer.

[0128] 22. The first communication device according to any one of embodiments 1 to 10, The circuit system is configured as follows: - Determine whether the detected collision detection indication information is assigned to the first communication device and / or instructs the first communication device to resolve the collision; and - If it has been determined that the detected conflict detection indication information has been assigned to the first communication device, then the steps of determining whether a conflict has occurred or reception failure and / or sending conflict resolution indication information are performed.

[0129] 23. A first communication device according to any one of embodiments 1 to 11 and 22, The first communication device is configured to operate as a station; and The conflict resolution instruction is configured to notify a second communication device configured to operate as a site to postpone channel access, and to notify a second communication device configured to operate as an access point to initiate a transmission opportunity and / or trigger a buffer status report from another second communication device.

[0130] 24. A first communication device according to any one of embodiments 1 to 12 and 22 to 23, The circuit system is configured as follows: - Based on one or more received collision detection indication messages including service set information, determine whether an OBSS collision has occurred, i.e., a collision with the transmission of a first or second communication device with an overlapping BSS (OBSS), wherein the service set information indicates the basic service set (BSS) of the second communication device; and - If an OBSS conflict occurs, perform one or more of the following: - Send a conflict resolution instruction message that indicates one or more of the following: the priority of subsequent transmissions, the identity of the second communication device that is allowed to initiate a transmission opportunity, one or more second communication devices that should postpone the initiation of a transmission opportunity; and its own BSS; - Delay channel access; -Initiate retreat; and -Including BSS-specific inter-frame intervals.

[0131] 25. The first communication device according to embodiment 24, Wherein, if the first communication device is configured to operate as an access point, the circuit system is configured not to send conflict resolution indication information if an OBSS conflict occurs with another first communication device of the OBSS; and / or Wherein, if the first communication device is configured to operate as a station, the circuit system is configured to send a conflict resolution indication message indicating that it is the sender and its BSS.

[0132] 26. A second communication device according to any one of embodiments 11 to 17, The circuit system is configured to initiate a transmission opportunity if the service set information included in the received collision detection indication information indicates its own basic service set (BSS), and if no collision detection indication information is received from the overlapping BSS (OBSS).

Claims

1. A first communication device configured to communicate with one or more second communication devices, the first communication device including a circuit system configured to: - Detecting collision detection indication information in a data unit received from one or more of the second communication devices, wherein the one or more of the second communication devices are configured to transmit a data unit including the collision detection indication information; - Based on one or more received collision detection indication messages, determine whether a collision has occurred or reception has failed; as well as - If a conflict or reception failure is determined to have occurred, a conflict resolution instruction message is sent, which indicates that a conflict or reception failure has occurred and / or indicates that at least one of the one or more second communication devices that caused the conflict or reception failure is to send.

2. The first communication device according to claim 1, in, The circuit system is configured to detect collision detection indication information in data units received from one or more second communication devices after performing contention-based channel access, during a predetermined service period, or during a predetermined time interval within an established transmission opportunity, wherein the one or more second communication devices are configured to transmit data units including collision detection indication information.

3. The first communication device according to claim 1, in, The circuit system is configured to acquire and / or instruct and / or exchange with the one or more second communication devices information indicating one or more of the following: - Distribution of conflict detection indication information to the one or more second communication devices; - Should the collision detection indication information be included in subsequent data units sent by one or more second communication devices? -Whether the subsequent data unit is able to initiate a transmission opportunity; - Does the collision detection indication information indicate the traffic priority and / or buffer status of the corresponding second communication device? -Configuration of conflict detection indication information; as well as - The maximum length of the data unit including collision detection indication information.

4. The first communication device according to claim 3, in, The circuit system is configured to acquire and / or indicate and / or exchange configuration information with the one or more second communication devices indicating collision detection indication information, the configuration of which includes one or more of the following: duration, modulation parameters, sequence type, subcarrier index allocation, time / symbol sequence index allocation, definition of trigger-based data units and / or transmission opportunity duration that the first communication device can set after the detection of a collision or reception failure.

5. The first communication device according to claim 1, in, The circuit system is configured to determine, based on one or more of the received collision detection indications, that a collision has occurred or a reception failure has occurred by detecting one or more of the following: - The transmission information that indicates the second communication device as the sender of the conflict detection indication information, included in the conflict detection indication information, does not match the transmission information included in the data unit received and correctly decoded by the first communication device; - At least one collision detection indication was detected, and decoding of the preamble and / or data field of one or more data units failed; - Receive at least two collision detection indication messages from different second communication devices.

6. The first communication device according to claim 1, in, The circuit system is configured to perform one or more of the following if no collision detection indication information is detected from the second communication device, but the first communication device knows that the second communication device should have sent the collision detection indication information: - Send a request to one or more second communication devices to change the configuration of the collision detection indication information; and - Send a collision detection report to one or more second communication devices, the collision detection report including information about the detection value of the collision detection indication information.

7. The first communication device according to claim 1, in, The circuit system is configured to send a conflict resolution indication message if a collision occurs or reception fails. The conflict resolution indication message is configured to notify at least one or more of the following to the one or more second communication devices indicated by the received conflict detection indication message: - Enable trigger-based channel access; - Schedule the transmission of one or more second communication devices; -Initiate a shared TXOP operation with the first communication device; - Delay channel access; - Move data exchange to another link; - Modify network assignment vector settings; - Send a response indicating whether the second communication device is involved in the conflict; - Indicates whether an OBSS conflict has occurred, wherein the OBSS conflict is a conflict with the transmission of a first or second communication device of an overlapping BSS (OBSS); - Indicates whether the second communication device is allowed to extract a new backoff counter and / or whether the second communication device is allowed to extract a new backoff counter without increasing the contention window; - Indicates whether the second communication device can use other channel access parameters; - Indicates whether the second communication device will be triggered in the upcoming transmission opportunity; as well as - Indicates whether the second communication device is able to initiate a transmission opportunity with mandatory collision detection indication information using only short frames and / or use a more robust configuration with said collision detection indication information.

8. The first communication device according to claim 1, in, The circuit system is configured to send a collision resolution instruction in a broadcast data unit if a collision or reception failure occurs. The broadcast data unit is configured to notify one or more of the following to a second communication device that previously transmitted the data unit: - Modify network assignment vector settings; - Delay channel access; - Whether the second communication device is allowed to extract a new backoff counter and / or whether the second communication device is allowed to extract a new backoff counter without increasing the contention window; - Indicates whether the second communication device can use other channel access parameters; as well as - Indicates whether the second communication device is able to initiate a transmission opportunity with mandatory collision detection indication information using only short frames and / or use a more robust configuration with said collision detection indication information.

9. The first communication device according to claim 1, in, The circuit system is configured as follows: - Perform a backoff process before transmitting the conflict resolution instruction information; or - When the wireless medium is identified as idle after a collision or packet error has been determined, a transmission opportunity is initiated without performing a backoff process by sending a data unit carrying a collision resolution instruction message, which schedules the transmission of the data unit of the second communication device. or - Preempt existing transmission opportunities to schedule the transmission of data units of the second communication device after the transmission of the conflict resolution instruction information of the first communication device.

10. The first communication device according to claim 1, in, The circuit system is configured to generate and / or indicate collision detection indication information to one or more second communication devices via one or more of the following configurations: - Define the duration of the conflict detection indication information within the data unit; - Define the number of different conflict detection indication messages; - Create a sequence of complex values ​​representing or included in collision detection indication information; - Modulate the complex-valued sequence into a waveform to be transmitted as a collision detection indication message; - Assign one or more collision detection indication messages to one or more second communication devices; as well as - Notify the second communication device associated with the first communication device of the allocation of one or more conflict detection indication messages to one or more second communication devices.

11. A second communication device configured to communicate with a first communication device, the first communication device being configured to communicate with one or more second communication devices, the second communication device including a circuit system configured to: - Sending data units including collision detection indication information; and - Receive from the first communication device a response or conflict resolution indication information for the transmitted data unit, the conflict resolution indication information indicating that a conflict or reception failure has occurred and / or indicating at least one of one or more second communication devices that sent the data unit that caused the conflict or reception failure.

12. The second communication device according to claim 11, in, The circuit system is configured to receive conflict resolution instruction information from the first communication device, the conflict resolution instruction information identifying the second communication device as a participant in a conflict as determined by the first communication device by detecting conflict detection instruction information.

13. The second communication device according to claim 11, in, The circuit system is configured to include the collision detection indication information in the preamble of the data unit, specifically in the physical layer preamble of the physical layer protocol data unit.

14. The second communication device according to claim 11, in, The circuit system is configured to transmit the data unit including the collision detection indication information after performing contention-based channel access, or during a predetermined service period, or during a predetermined time interval within an established transmission opportunity, and / or is configured to include the collision detection indication information in one or more of the following: - The first data unit transmitted after performing contention-based channel access; - Data units transmitted during service periods when one or more second communication devices are permitted to transmit; as well as - A data unit that carries preemption indication information and / or preemption data.

15. The second communication device according to claim 11, in, The circuit system is configured to include one or more of the following into the collision detection indication information: - The second communication device is designated as the sender of the conflict detection indication information; - Designate the first communication device as the recipient of the conflict detection information and / or as the target information of the device to resolve the conflict; as well as - Service set information indicating the basic service set of the second communication device.

16. The second communication device according to claim 11, in, The circuit system is configured to perform one or more of the following in response to a received conflict resolution instruction: - Sending a response and / or a data unit containing data; - Trigger-based channel access is performed by sending trigger-based data units; - Send traffic according to the received schedule; -Initiate a shared TXOP operation with the first communication device; - Delay channel access; - Move data exchange to another link; - Modify network assignment vector settings; - Send a response indicating whether the second communication device is involved in the conflict; - Extract a new retreat counter; - If the second communication device is not indicated or the channel access of the second communication device is postponed in the collision detection indication information, a new backoff counter is extracted without increasing the contention window; - Use other channel access parameters; - Only use short frames to initiate transmission opportunities with mandatory collision detection indication information; as well as - A more robust configuration using the aforementioned conflict detection indication information.

17. The second communication device according to claim 11, in, The circuit system is configured to modulate one or more complex-valued sequences into waveforms to be transmitted as collision detection indication information.

18. A first communication method for a first communication device, the first communication device being configured to communicate with one or more second communication devices, the first communication method comprising: - Detecting collision detection indication information in a data unit received from one or more of the second communication devices, wherein the one or more of the second communication devices are configured to transmit a data unit including the collision detection indication information; - Based on one or more received collision detection indication messages, determine whether a collision has occurred or reception has failed; as well as - If a conflict or reception failure is determined to have occurred, a conflict resolution instruction message is sent, which indicates that a conflict or reception failure has occurred and / or indicates that at least one of the one or more second communication devices that caused the conflict or reception failure is to send.

19. A second communication method for a second communication device, the second communication device being configured to communicate with a first communication device, the first communication device being configured to communicate with one or more second communication devices, the second communication method comprising: - Send a data unit that includes collision detection indication information; as well as - Receive from the first communication device a response or conflict resolution indication information for the transmitted data unit, the conflict resolution indication information indicating that a conflict or reception failure has occurred and / or indicating at least one of one or more second communication devices that sent the data unit that caused the conflict or reception failure.

20. A non-transitory computer-readable recording medium storing a computer program product therein, the computer program product causing, when executed by a processor, to perform the method according to claim 18 or 19.

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