Devices and methods for coordinated spatial reuse in a wireless network

Abstract

An access point, AP, is disclosed for providing network access to one or more non-AP stations associated with the AP and for sharing communication resources of the AP with one or more overlapping basic service set, OBSS, APs in a Multi-AP, M-AP, coordinated transmission under a common M-AP coordination agreement, when the AP obtains a transmission opportunity, TXOP. The AP is configured to transmit during the TXOP a downlink, DL, physical layer protocol data unit, PPDU, to the one or more non-AP stations associated with the AP. The DL PPDU comprises a preamble, wherein the preamble comprises a Coordinated Spatial Reuse, CSR, indication indicative of one or more CSR control parameters for controlling a CSR transmission of a respective further DL PPDU by the one or more OBSS APs to one or more non-AP stations associated with the respective OBSS AP in parallel to the DL PPDU within the TXOP.

Description

[0001] DEVICES AND METHODS FOR COORDINATED SPATIAL REUSE IN A WIRELESS NETWORK

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to wireless communications. More specifically, the present disclosure relates to devices and methods for coordinated spatial reuse by a group of access points, APs, in a wireless communication network, in particular a wireless local area network, WLAN, (also referred to as Wi-Fi network) in accordance with the IEEE 802.11 framework of standards.

[0004] BACKGROUND

[0005] Coordinated Spatial Reuse, CSR or Co-SR, was accepted as a Multi- AP, MAP, coordination scheme for the next generation of the IEEE 802.11 framework of standards. In the CSR scheme APs transmit concurrent DL PPDUs while transmit power is controlled to minimize interference. A TXOP based CSR has been introduced, where the TXOP owner (also referred to as Sharing AP) may announce one or several OBSS APs (also referred to as Shared APs) that they are invited to participate in current TXOP. It has been further defined that the Sharing AP may control the transmit power of Shared APs to ensure desired interference signal at the receiver.

[0006] SUMMARY OF THE INVENTION

[0007] It is an objective of the present disclosure to provide improved devices, in particular access points, APs, and methods allowing for an efficient exchange of control information in a coordinated spatial reuse scheme by a group of access points, APs, in a wireless communication network, in particular a wireless local area network, WLAN, (also referred to as Wi-Fi network) in accordance with the IEEE 802.11 framework of standards.

[0008] The foregoing and other objectives are achieved by the subject matter of the independent claims. Further implementation forms are apparent from the dependent claims, the description and the figures. In the following one or more of the following acronyms and abbreviations may be used:

[0009] A-MPDU Aggregated MPDU

[0010] AP Access Point

[0011] BF Beamforming

[0012] BW Bandwidth

[0013] CoBF Coordinated Beamforming

[0014] CSI Channel State Information

[0015] CSR Coordinated Spatial Reuse

[0016] DL Downlink

[0017] LAN Local Area Network

[0018] MAP Multiple Access Points

[0019] MAC Media Access Control

[0020] MIMO Multiple In Multiple Out

[0021] MPDU MAC Protocol Data Unit

[0022] NDP Null Data PPDU

[0023] NDPR Null Data PPDU Request OBSS Overlapping Basic Serving Set

[0024] OFDMA Orthogonal Frequency-Division Multiple Access

[0025] PER Packet Error Ratio

[0026] PEIY Physical (layer)

[0027] PPDU Physical Layer Protocol Data Unit

[0028] RU Resource Unit

[0029] SNR Signal to Noise Ratio

[0030] STA Station

[0031] SVD Single Value Decomposition

[0032] TB Trigger Based

[0033] TDMA Time Division Multiple Access

[0034] TF Trigger Frame

[0035] TXOP Transmit Opportunity

[0036] UL Uplink

[0037] WLAN Wireless LAN

[0038] According to a first aspect an access point, AP, is disclosed for providing network access to one or more non-AP stations associated with the AP and for sharing communication resources of the AP with one or more overlapping basic service set, OBSS, APs in a Multi-AP, M-AP, coordinated transmission under a common, i.e. the same M-AP coordination agreement, when the AP obtains a transmission opportunity, TXOP, wherein the AP is configured to transmit during the TXOP a downlink, DL, physical layer protocol data unit, PPDU, to the one or more non-AP stations associated with the AP. The DL PPDU comprises a PHY preamble, wherein the preamble comprises a Coordinated Spatial Reuse, CSR, indication indicative of one or more CSR control parameters for controlling a CSR transmission of a respective further DL PPDU by the one or more OBSS APs to one or more non-AP stations associated with the respective OBSS AP in parallel to the DL PPDU within the TXOP.

[0039] In a further possible implementation form, the one or more CSR control parameters for controlling the CSR transmission of a respective further DL PPDU by the one or more OBSS APs to one or more non-AP stations associated with the respective OBSS AP in parallel to the DL PPDU within the TXOP are indicative of whether or not a CSR transmission is allowed for the one or more OBSS APs in parallel to the DL PPDU within the TXOP.

[0040] In a further possible implementation form, the DL PPDU is an EHT or UHR MU DL PPDU, wherein the EHT or UHR MU DL PPDU comprises a U-SIG field and wherein at least one bit, in particular at least one of the Disregard bits (B20-B24), of the U-SIG field comprises the CSR indication for indicating whether or not a CSR transmission is allowed for the one or more OBSS APs in parallel to the DL PPDU within the TXOP.

[0041] In a further possible implementation form, the PHY preamble comprises a CSR Information field and the CSR Information field contains, i.e. comprises the CSR indication.

[0042] In a further possible implementation form, the CSR Information field contains a subfield indicating the number of the one or more OBSS APs.

[0043] In a further possible implementation form, the PHY preamble comprises for each OBSS AP a CSR Information field and each CSR Information field comprises an identifier of the respective OBSS AP and a CSR indication indicative of one or more CSR control parameters for controlling a CSR transmission of a respective further DL PPDU by the respective OBSS AP to the one or more non-AP stations associated with the respective OBSS AP in parallel to the DL PPDU within the TXOP. In a further possible implementation form, the CSR indication comprises a bit sequence encoding one of at least two different transmission powers from a plurality, e.g. codebook of transmission powers.

[0044] In a further possible implementation form, the bit sequence encodes one of at least two different transmission powers from a plurality, e.g. codebook of transmission powers and a mode for which CSR transmission is not allowed for the one or more OBSS APs in parallel to the DL PPDU within the TXOP.

[0045] In a further possible implementation form, the DL PPDU comprises a UHR-SIG field, wherein the UHR-SIG field comprises the bit sequence.

[0046] In a further possible implementation form, the PPDU comprises a U-SIG field and a bit of the U-SIG field is indicative of the presence of the bit sequence in the UHR-SIG field.

[0047] In a further possible implementation form, a padding portion of the UHR-SIG field comprises the bit sequence.

[0048] In a further possible implementation form, the CSR indication further comprises a flag bit indicative of whether or not CSR transmission is allowed for the one or more OBSS APs in parallel to the DL PPDU within the TXOP.

[0049] In a further possible implementation form, the DL PPDU comprises a UHR-SIG field, wherein the UHR-SIG field comprises the bit sequence and the flag bit.

[0050] In a further possible implementation form, the PPDU comprises a U-SIG field and a bit of the U-SIG field is indicative of the presence of the bit sequence and the flag bit in the UHR-SIG field.

[0051] In a further possible implementation form, a padding portion of the UHR-SIG field comprises the bit sequence and the flag bit.

[0052] According to a second aspect a method is provided for operating an access point, AP, for providing network access to one or more non-AP stations associated with the AP and for sharing communication resources of the AP with one or more overlapping basic service set, OBSS, APs in a Multi-AP, M-AP, coordinated transmission under a common, i.e. the same M-AP coordination agreement, when the AP obtains a transmission opportunity, TXOP. The method according to the second aspect comprises transmitting by the AP during the TXOP a downlink, DL, physical layer protocol data unit, PPDU, to one or more non-AP stations associated with the AP. The DL PPDU comprises a PHY preamble, wherein the preamble comprises a Coordinated Spatial Reuse, CSR, indication indicative of one or more CSR control parameters for controlling a CSR transmission of a respective further DL PPDU by the one or more OBSS APs to one or more non-AP stations associated with the respective OBSS AP in parallel to the DL PPDU within the TXOP.

[0053] The method according to the second aspect can be performed by the AP according to the first aspect. Thus, further features of the method according to the second aspect result directly from the functionality of the AP according to the first aspect, as well as its different implementation forms described above and below.

[0054] According to a third aspect a computer program product is provided, comprising program code which causes a computer or a processor to perform the method according to the second aspect, when the program code is executed by the computer or the processor.

[0055] Details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In the following, embodiments of the present disclosure are described in more detail with reference to the attached figures and drawings, in which:

[0057] Fig. 1 shows a schematic diagram illustrating a wireless communication network, in particular a WLAN including an AP according to an embodiment with a plurality of associated non-AP stations and an OBSS AP with a further plurality of associated non-AP stations;

[0058] Fig. 2 shows a schematic diagram illustrating different stages of an example of a CSR scheme implemented by an AP and an OBSS AP;

[0059] Fig. 3 shows a schematic diagram illustrating different stages of a CSR scheme implemented by an AP and an OBSS AP according to an embodiment;

[0060] Fig. 4 shows a comparison of the CSR scheme of Fig. 2 with the CSR scheme of Fig. 3 implemented by an AP according to an embodiment illustrating the reduced overhead;

[0061] Fig. 5 shows a schematic diagram illustrating a UHR SIG field of a preamble of a frame including a CSR Information field according to an embodiment;

[0062] Fig. 6 shows a schematic diagram illustrating a single CSR Information field according to an embodiment relevant for all shared APs;

[0063] Fig. 7 shows a schematic diagram illustrating a CSR Information field according to an embodiment with a subfield for each shared AP;

[0064] Fig. 8 shows a schematic diagram illustrating a subfield per shared AP of a CSR Information field according to an embodiment; and

[0065] Fig. 9 shows a flow diagram illustrating steps of a method according to an embodiment for operating an AP.

[0066] In the following, identical reference signs refer to identical or at least functionally equivalent features.

[0067] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0068] In the following description, reference is made to the accompanying figures, which form part of the disclosure, which illustrates specific aspects of embodiments of the present disclosure or specific aspects in which embodiments of the present disclosure may be used. It is understood that embodiments of the present disclosure may be used in other aspects and comprise structural or logical changes not depicted in the figures. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present disclosure is defined by the appended claims.

[0069] For instance, it is to be understood that a disclosure in connection with a described method may also hold true for a corresponding device or system configured to perform the method and vice versa. For example, if one or a plurality of specific method steps are described, a corresponding device may include one or a plurality of units, e.g. functional units, to perform the described one or plurality of method steps (e.g. one unit performing the one or plurality of steps, or a plurality of units each performing one or more of the plurality of steps), even if such one or more units are not explicitly described or illustrated in the figures. On the other hand, for example, if a specific apparatus is described based on one or a plurality of units, e.g. functional units, a corresponding method may include one step to perform the functionality of the one or plurality of units (e.g. one step performing the functionality of the one or plurality of units, or a plurality of steps each performing the functionality of one or more of the plurality of units), even if such one or plurality of steps are not explicitly described or illustrated in the figures. Further, it is understood that the features of the various exemplary embodiments and / or aspects described herein may be combined with each other, unless specifically noted otherwise.

[0070] Fig. 1 shows a wireless communication system 100, in particular a wireless local area network, WLAN, 100 in accordance with the IEEE 802.11 framework of standards (also referred to as a Wi-Fi network 100). The WLAN 100 comprises an access point, AP, 110 in communication with a plurality of non-AP stations HOa-c associated with the AP 110. The WLAN 100 further comprises at least one further AP 120 (which relative to the AP 110 is designated as an OBSS AP 120) in communication with a further plurality of non-AP stations 120a-c associated with the further AP 120. As illustrated in Fig. 1 , by way of example, the non-AP stations 1 lOa-c associated with the AP 110 and the further non-AP stations 120a-c, i.e. the non-AP stations 120a- c associated with the OBSS AP 120 may comprise smartphones, laptop computers, tablet computers, desktop computers or other types of wireless devices configured to be associated with an AP. As indicated in Fig. 1, the AP 110 and the at least one OBSS AP 120 may exchange frames with each other and with their respective associated non-AP stations 1 lOa-c, 120a-c.

[0071] As further illustrated in Fig. 1, the AP 110 may comprise a processing circuitry 111 and a communication interface 113, in particular a wireless communication interface 113 enabling communication in accordance with the IEEE 802.11 framework of standards. The processing circuitry 111 may be implemented in hardware and / or software and may comprise digital circuitry, or both analog and digital circuitry. Digital circuitry may comprise components such as application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), digital signal processors (DSPs), or general-purpose processors. The AP 110 may further comprise a memory 115 configured to store executable program code which, when executed by the processing circuitry 111, causes the AP 110 to perform the functions and methods described herein.

[0072] Also, the OBSS AP 120 may comprise a processing circuitry 121 and a communication interface 123, in particular a wireless communication interface 123 enabling communication in accordance with the IEEE 802.11 framework of standards. The processing circuitry 121 may be implemented in hardware and / or software and may comprise digital circuitry, or both analog and digital circuitry. Digital circuitry may comprise components such as application-specific integrated circuits (ASICs), field- programmable gate arrays (FPGAs), digital signal processors (DSPs), or general-purpose processors. The OBSS AP 120 may further comprise a memory 125 configured to store executable program code which, when executed by the processing circuitry 121, causes the further AP 120 to perform the functions and methods described herein.

[0073] Likewise, each of the non-AP stations 1 lOa-c, 120a-c may comprise a processing circuitry and a communication interface (not illustrated in Fig. 1), in particular a wireless communication interface enabling a communication in accordance with the IEEE 802.11 framework of standards. The processing circuitry may be implemented in hardware and / or software and may comprise digital circuitry, or both analog and digital circuitry. Digital circuitry may comprise components such as application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), digital signal processors (DSPs), or general-purpose processors. Each non-AP station 1 lOa-c, 120a-c may further comprise a memory (not illustrated in Fig. 1) configured to store executable program code which, when executed by the processing circuitry of the non-AP station, causes the non-AP station to perform the functions and methods described herein.

[0074] As will be described in more detail below, the AP 110 and the at least one OBSS AP 120 of Fig. 1 are configured to implement a Coordinated Spatial Reuse, CSR, scheme. As already mentioned above, CSR has been accepted as a MAP coordination scheme in the IEEE 802.11 framework of standards. In a CSR scheme APs transmit concurrent DL PPDUs while transmit power is controlled to minimize interference. In IEEE 802. Il a TXOP based CSR scheme has been accepted, where the TXOP owner, i.e. the sharing AP may announce one or several OBSS APs, i.e. shared APs that they are invited to participate in a current TXOP. In IEEE 802.11 it is also defined that the sharing AP may control the transmit power of the shared APs to ensure desired interference signal at the receiver.

[0075] As will be described in more detail below, embodiments disclosed herein allow for a more efficient way of exchanging the CSR control parameters between APs, such as between the AP 110, i.e. the sharing AP 110 and the at least one OBSS AP 120, i.e. shared AP 120 of Fig. 1. In an embodiment, the CSR scheme implemented by the sharing AP 110 and the at least one shared AP 120 may be based on or be configured in accordance with one or more of the following principles. All the shared APs 120 may be determined / selected either in a Coordination Agreement negotiation setting procedure or at the beginning of a TXOP. A PPDU may include all the shared APs 120 or any subset of the shared APs 120, but only those that were announced at the beginning of a TXOP. The sharing AP 110 may decide to allow CSR transmission for each shared AP 120 per PPDU within a specific TXOP (some shared AP may be not allowed to transmit in parallel to the specific PPDU). The sharing AP 110 may control the Tx power of the shared APs 120, not vice versa. F or instance, the sharing AP 110 may indicate a required maximum Tx power for the shared AP 120. The shared AP 120 may have no opportunity to request or indicate a desired Tx power to the sharing AP 110. Thus, the shared AP 120 may decide to transmit or not and which parameters to apply for its transmission according to the restriction(s) indicated by the sharing AP 110. The APs 110, 120 may have a priori information for the interference level of each OBSS AP (measured and reported by the STAs based on beacon transmissions of OBSS AP). The start of a PPDU transmitted by the shared AP 110 does not have to be aligned with the start of Sharing AP’s PPDU (at least for those cases where Interference Mitigation is not applied at the receiver).

[0076] Power Control is the main tool of a CSR scheme. As already mentioned above, it may be assumed that the non-AP stations 1 lOa-c, 120a-c measure the interference signal from OBSS APs 110, 120 and report the results to the AP 110. The sharing AP 110 may use these reports to control the Tx power of the shared APs 120. The shared APs 120 may also use the reported information to decide on transmission parameters according to power control indicated by the sharing AP 110.

[0077] Embodiments disclosed herein are based on the two following main principles. Firstly, the non-AP stations HOa-c, 120a-c measure and report the interference information based on the broadcasted frames, such as beacons transmitted by the OBSS AP(s) 120. Transmission of those frames is managed by the OBSS AP(s) 120 and may not be triggered by another AP. Secondly, all the information regarding interference from OBSS APs 120 may be collected by the sharing AP 110 at the beginning of a TXOP and may be used during the TXOP to define CSR parameters.

[0078] In the CSR scheme illustrated in Fig. 2 the CSR TF 13 is part of a CSR transmission phase that provides the CSR parameters and also aligns the start of the CSR PPDUs 14a, b. However, as illustrated above, although each CSR PPDU 14a, b may have different parameters, all of them are known at the beginning of the TXOP and may be indicated once in each TXOP (or even once per several TXOPs). Moreover, it has been assumed that the CSR PPDUs 14a, b may not be aligned and thus a TF is not required to synchronize the transmitting APs (at least for those cases where interference mitigation is not applied at the receiver). Moreover, the sharing AP 11 may define a Tx power restriction such that its own transmission is not interfered. But from the perspective of the shared AP 11 it might be a too confined requirement that may even prevent the shared AP 11 from earning any benefit by transmitting concurrently. Thus, the CSR TF 13 of the CSR scheme of Fig. 2 may be considered an overhead that is paid by sharing AP 11 per each CSR PPDU transmission. To address these issues embodiments disclosed herein provide an improved CSR scheme allowing the indication of CSR parameters with minimum overhead for the sharing AP, as will be described in more detail in the following.

[0079] Fig. 3 shows a schematic diagram illustrating different stages of an improved CSR scheme implemented by the AP 110 and the at least one OBSS AP 120 according to an embodiment. As already described above in the context of Fig. 1, the AP 110 is configured to provide network access to the non-AP stations 1 lOa-c associated with the AP 110 and to share communication resources of the AP 110 (i.e. the sharing AP 110) with the one or more OBSS APs 120 (i.e. the one or more shared APs 120) in a Multi-AP, MAP, coordinated transmission under a common, i.e. the same MAP coordination agreement, when the sharing AP 110 obtains a transmission opportunity, TXOP, 300. As illustrated in Fig. 3, the sharing AP 110 is further configured to transmit during the TXOP 300 a downlink, DL, physical layer protocol data unit, PPDU, 320 to the one or more non-AP stations 1 lOa-c associated with the AP 110, wherein the DL PPDU 320 comprises a PHY preamble 320a (and a data portion 320b) and wherein the PHY preamble 320a comprises a Coordinated Spatial Reuse, CSR, indication 340 indicative of one or more CSR control parameters for controlling a CSR transmission of a respective further DL PPDU 330 by the one or more OBSS APs 120 to the one or more non-AP stations 120a-c associated with the respective OBSS AP 120 in parallel to the DL PPDU 320 within the TXOP 300. As will be appreciated, by including the CSR indication 340 in the PHY preamble 320a of the PPDU 320, the OBSS AP 120 may use the one or more CSR control parameters indicated by the CSR indication 340 for transmitting its PPDU 330 (which comprises a PHY preamble 330a and a data portion 330b as well), once the OBSS AP 120 has extracted the one or more CSR control parameters from the PHY preamble 320a of the PPDU 320. In an embodiment, the AP 110 may further transmit a CSR Announcement frame 310 for preparing the one or more OBSS APs 120 for the transmission of the PPDU 320. In an embodiment, the CSR Announcement frame 310 may comprise one or more further CSR control parameters complementing the one or more CSR control parameters indicated by the CSR indication 340 included in the preamble 320a of the PPDU 320. As will be appreciated, in Fig. 3 the AP 110 is transmitting, by way of example, two PPDUs 320 during the TXOP 300.

[0080] Fig. 4 shows a comparison of the CSR scheme of Fig. 2 with the CSR scheme of Fig. 3 implemented by the AP 110 according to an embodiment illustrating the reduced overhead provided by the CSR scheme of Fig. 3.

[0081] In an embodiment, the CSR indication 340 included in the preamble 320a of the PPDU 320 may indicate whether CSR is allowed for the shared AP(s) 120 for the current PPDU 320. This enables the sharing AP 110 to decide to allow or not allow the CSR according to its own needs and channel conditions. In an embodiment, the sharing AP 110 may indicate that CSR is allowed or not allowed by using a CSR indication 340 in the form of a single flag bit. For such an embodiment, all the shared APs 120 should follow the same rule, either transmit or not transmit. The required Tx power level is the same for all the shared APs 120 and should be indicated by the sharing AP at the beginning of the TXOP 300, for instance, by means of the CSR Announcement frame 310. In a further embodiment, the sharing AP 110 may be configured to allow CSR transmission only to a subset of the shared APs 120 by means of the CSR indication 340, as will be described in more detail below. The one-bit CRS indication 340 may be included in the U-SIG field, for instance, one of the Disregard bits (B20-B24) of the U-SIG field.

[0082] According to further embodiments, the sharing AP 110 may be configured to provide several options for the Tx power at the beginning of the TXOP 300 and then indicate by means of the CSR indication 340 which of these Tx power options are to be used by the shared AP(s) 120 during the current PPDU 320. For example, the sharing AP 110 may indicate four different Tx power values, and indicate by the CSR indication 340 in the form of two bits which specific Tx power value should be applied. In this case, similar to the previous embodiment, all the shared APs 120 may use the same Tx power value indicated by the two-bit CSR indication 340. In a further embodiment, the CSR indication 340 may comprise N bits, wherein one combination of the bits of the CSR indication 340 encode the information “CSR is not allowed” and the other bit combinations may encode the information “CSR is allowed with a specific Tx power value to be applied”. In further embodiments described in more detail in the following, the CSR indication 340 may be configured to indicate specific CSR control parameters for specific OBSS APs 120, i.e. the CSR indication 340 may indicate CSR parameters per shared AP 120. In an embodiment, the CSR indication 340 may be contained in a CSR Information field. Fig. 5 shows an embodiment, wherein the CSR Information field 505 containing the CSR indication 340 is part of a UHR-SIG field (UHR variant of EHT- SIG). In an embodiment, the presence of the CSR Information field 505 may be indicated by a single bit in U-SIG. As illustrated in Fig. 5, in addition to the CSR Information field 505 containing the CSR indication 340 the UHR-SIG field may further comprise several User Fields 501a-n, Tail and CRC fields 503a-n and a padding bits 507. In an embodiment, the CSR Information field 505 may be part of or adjacent to the padding bits 507. It may be assumed that the UHR-SIG will have a similar format as the EHT-SIG, where there is the list of User Fields 501a-n corresponding to the all the non-AP stations 110a- c allocated in the current PPDU 320.

[0083] As will be appreciated, by including the CSR Information field 505 containing the CSR indication in the padding bits 507, the CSR Information field 505 will be treated as padding bits the non-AP stations 1 lOa-c and, therefore, will not negatively impact the behavior of the non-AP stations 1 lOa-c, while being decodable by the shared AP(s) 120 for extracting the one or more CSR control parameters indicated by the CSR indication 340 contained in the CSR Information field 505.

[0084] Fig. 6 shows a schematic diagram illustrating a single CSR Information field 505 according to an embodiment relevant for all shared APs 120. In this embodiment, the CSR Information field 505 may comprise a subfield 601 for indicating the number of shared APs 120 included in the CSR Information field 505 as well as respective AP identifiers 603a-n and one or more CSR control parameters including a Tx power parameter 605a-n for each shared AP 120. As all the bits of the single CSR Information field 505 may be encoded together, tail bits and CRC 607 may be added at the end of the CSR Information field 505.

[0085] Fig. 7 shows a schematic diagram illustrating a CSR Information field 505 according to an embodiment with a CSR subfield 701a-n for each shared AP 120. In this embodiment, each CSR subfield 701a-n of the CSR Information field 505 may be followed by tail bits and CRC 703a-n. Fig. 8 shows a schematic diagram illustrating an embodiment of a respective CSR subfield 701a-n per shared AP 120 of the CSR Information field 505 of Fig. 7. As illustrated in Fig. 8, the CSR subfield 701a- n for each shared AP 120 may comprise an AP identifier 801 and one or more CSR control parameters including a Tx power parameter 803 for that shared AP 120. Tail bits and CRC 805 may be added at the end of each CSR subfield 701a-n.

[0086] Fig . 9 shows a flow diagram illustrating a method 900 for operating an AP, such as the AP 110 of Fig . 1 , for providing network access to the non-AP stations 1 lOa-c associated with the AP 110 and for sharing communication resources of the AP 110 with the at least one OBSS AP 120 in a MAP coordinated transmission under a common, i.e. the same MAP coordination agreement, when the AP 110 obtains a TXOP 300. The method 900 comprises a step 901 of transmitting by the AP 110 during the TXOP 300 a downlink, DL, physical layer protocol data unit, PPDU, 320 to the non-AP stations 1 lOa-c associated with the AP 110. As alreadv described above, the DL PPDU 320 comprises a preamble 320a and the preamble 320a comprises a Coordinated Spatial Reuse, CSR, indication 340 indicative of one or more CSR control parameters for controlling a CSR transmission of a respective further DL PPDU 330 by the OBSS AP(s) 120 to one or more non-AP stations 120a-c associated with the respective OBSS AP 120 in parallel to the DL PPDU 320 within the TXOP 300.

[0087] The person skilled in the art will understand that the "blocks" ("units") of the various figures (method and apparatus) represent or describe functionalities of embodiments of the present disclosure (rather than necessarily individual "units" in hardware or software) and thus describe equally functions or features of apparatus embodiments as well as method embodiments (unit = step).

[0088] In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus, and method may be implemented in other manners. For example, the described embodiment of an apparatus is merely exemplary. For example, the unit division is merely logical function division and may be another division in an actual implementation. For example, a plurality of units or components may be combined or integrated into another system, or some features may be ignored or not performed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections may be implemented by using some interfaces. The indirect couplings or communication connections between the apparatuses or units may be implemented in electronic, mechanical, or other forms.

[0089] The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one position, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the objectives of the solutions of the embodiments.

[0090] In addition, functional units in the embodiments of the disclosure may be integrated into one processing unit, or each of the units may exist alone physically, or two or more units are integrated into one unit.

Claims

CLAIMS1. An access point, AP, (110) for providing network access to one or more non-AP stations (1 lOa-c) associated with the AP (110) and for sharing communication resources of the AP (110) with one or more overlapping basic service set, OBSS, APs (120) in a Multi-AP, MAP, coordinated transmission under a common MAP coordination agreement, when the AP (110) obtains a transmission opportunity, TXOP (300), wherein the AP (110) is configured to: transmit during the TXOP (300) a downlink, DL, physical layer protocol data unit, PPDU, (320) to the one or more non-AP stations (1 lOa-c) associated with the AP (110), wherein the DL PPDU (320) comprises a preamble (320a) and wherein the preamble (320a) comprises a Coordinated Spatial Reuse, CSR, indication (340; 803) indicative of one or more CSR control parameters for controlling a CSR transmission of a respective further DL PPDU (330) by the one or more OBSS APs (120) to one or more non-AP stations (120a-c) associated with the respective OBSS AP (120) in parallel to the DL PPDU (320) within the TXOP (300).

2. The AP (110) of claim 1, wherein the one or more CSR control parameters for controlling the CSR transmission of a respective further DL PPDU (330) by the one or more OBSS APs (120) to one or more non-AP stations (120a-c) associated with the respective OBSS AP (120) in parallel to the DL PPDU (320) within the TXOP (300) are indicative of whether or not a CSR transmission is allowed for the one or more OBSS APs (120) in parallel to the DL PPDU (320) within the TXOP (300).

3. The AP (110) of claim 2, wherein the DL PPDU (320) is an EHT or UHR MU DL PPDU (320), wherein the EHT or UHR MU DL PPDU (320) comprises a U-SIG field and wherein at least one bit of the U-SIG field comprises the CSR indication (340) for indicating whether or not a CSR transmission is allowed for the one or more OBSS APs (120) in parallel to the DL PPDU (320) within the TXOP (300).

4. The AP (110) of any one of the preceding claims, wherein the preamble (320) comprises a CSR Information field (505) and wherein the CSR Information field (505) contains the CSR indication (340).

5. The AP (110) of claim 4, wherein the CSR Information field (505) contains a subfield (601) indicating the number of the one or more OBSS APs (120).

6. The AP (110) of any one of claims 1 to 3, wherein the preamble (320a) comprises for each OBSS AP (120) a CSR Information field (701a-n) and wherein each CSR Information field (701a-n) comprises an identifier (801) of the respective OBSS AP (120) and a CSR indication (803) indicative of one or more CSR control parameters for controlling a CSR transmission of a respective further DL PPDU (330) by the respective OBSS AP (120) to the one or more non-AP stations (120a-c) associated with the respective OBSS AP (120) in parallel to the DL PPDU (320) within the TXOP (300).

7. The AP (110) of any one of the preceding claims, wherein the CSR indication (803) comprises a bit sequence encoding one of at least two different transmission powers.

8. The AP (110) of claim 7, wherein the bit sequence encodes one of at least two different transmission powers and a mode for which CSR transmission is not allowed for the one or more OBSS APs (120) in parallel to the DL PPDU (320) within the TXOP (300).

9. The AP (110) of claim 7 or 8, wherein the DL PPDU (320) comprises a UHR-SIG field and wherein the UHR-SIG field comprises the bit sequence.

10. The AP (110) of claim 9, wherein the DL PPDU (320) comprises a U-SIG field and wherein a bit of the U-SIG field is indicative of the presence of the bit sequence in the UHR-SIG field.

11. The AP (110) of claim 9 or 10, wherein a padding portion of the UHR-SIG field comprises the bit sequence.

12. The AP (110) of claim 7, wherein the CSR indication (803) further comprises a flag bit indicative of whether or not CSR transmission is allowed for the one or more OBSS APs (120) in parallel to the DL PPDU (320) within the TXOP (300).

13. The AP (110) of claim 12, wherein the DL PPDU (320) comprises a UHR-SIG field and wherein the UHR-SIG field comprises the bit sequence and the flag bit.

14. The AP (110) of claim 13, wherein the DL PPDU (320) comprises a U-SIG field and wherein a bit of the U-SIG field is indicative of the presence of the bit sequence and the flag bit in the UHR-SIG field.

15. The AP (110) of claim 14, wherein a padding portion of the UHR-SIG field comprises the bit sequence and the flag bit.

16. A method (900) for operating an access point, AP, (110) for providing network access to one or more non-AP stations (1 lOa-c) associated with the AP (110) and for sharing communication resources of the AP (110) with one or more overlapping basic service set, OBSS, APs (120) in a Multi-AP, MAP, coordinated transmission under a common MAP coordination agreement, when the AP (110) obtains a transmission opportunity, TXOP (300), wherein the method (900) comprises: transmitting (901) by the AP (110) during the TXOP (300) a downlink, DL, physical layer protocol data unit, PPDU, (320) to the one or more non-AP stations (HOa-c) associated with the AP (110), wherein the DL PPDU (320) comprises a preamble (320a) and wherein the preamble (320a) comprises a Coordinated Spatial Reuse, CSR, indication (340) indicative of one or more CSR control parameters for controlling a CSR transmission of a respective further DL PPDU (330) by the one or more OBSS APs (120) to one or more non-AP stations (120a-c) associated with the respective OBSS AP (120) in parallel to the DL PPDU (320) within the TXOP (300).

17. A computer program product comprising a computer-readable storage medium for storing program code which causes a computer or a processor to perform the method (900) of claim 16, when the program code is executed by the computer or the processor.

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