Frequency-selective service period

Abstract

Frequency-selective service period An access point (10) of a wireless communication system operates on a first wireless channel. The access point (10) sends an indication of at least one scheduled service period for transmission of first data traffic of a group of one or more devices. The indication comprises information on frequency resources of the first wireless channel which are reserved for the first data traffic. Further, the access point (10) participates in transmission of at least a part of the first data traffic on the reserved frequency resources.

Description

[0001] Frequency-selective service period

[0002] Technical Field

[0003] The present invention relates to methods for controlling wireless transmissions and to corresponding devices, systems, and computer programs.

[0004] Background

[0005] Wireless communication technologies may use licensed frequency bands and / or licenseexempt frequency bands. A typical example of a wireless communication technology operating in license-exempt frequency bands is the WLAN (Wireless Local Area Network) technology, according to "IEEE Standard for Information Technology-Telecommunications and Information Exchange between Systems - Local and Metropolitan Area Networks-Specific Requirements - Part 11 : Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications," in IEEE Std 802.11-2020 (Revision of IEEE Std 802.11-2016), pp.1- 4379, 26 Feb. 2021 , in the following denoted as “IEEE 802.11 standard”. The WLAN technology based on the IEEE 802.11 Standard is also referred to as “Wi-Fi”.

[0006] In a recent amendment to the IEEE 802.11 standard, “IEEE Standard for Information Technology-Telecommunications and Information Exchange between Systems Local and Metropolitan Area Networks-Specific Requirements Part 11 : Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications Amendment 1 : Enhancements for High-Efficiency WLAN”, in the following denoted as “802.11 ax Amendment”, a functionality denoted as target wake-up time (TWT) was introduced. The TWT functionality allows an AP (Access Point) to schedule activity in the BSS (Basic Service Set), with the aim of reducing contention between STAs (stations). Further, the TWT functionality can be used for reducing the required amount of time that a STA utilizing a power management mode needs to be awake. The TWT functionality allows STAs to allocate and operate at nonoverlapping times and / or frequencies, and to concentrate the frame exchanges in predefined service periods (SPs).

[0007] TWT SPs may be set up by negotiation of individual TWT agreements among AP and STA(s) or by announcement of TWT SPs in beacon frames transmitted by the AP. The latter variant is denoted as “Broadcast TWT announcement”. Broadcast TWT announcements indicate upcoming SPs and information about which member STAs should be prepared to participate. In both cases, it is to be noted that even though an AP can force a TWT capable STA to either join a broadcast TWT schedule or set up an individual TWT agreement, the STA may immediately teardown the TWT agreement. To support such negotiations, there are several options that can be signaled between devices to reach an agreement that both sides are satisfied with. Furthermore, an SP may be terminated by an AP if the SP is no longer required for delivery of data, e.g., due to overprovisioning.

[0008] In “Standard for Information technology-Telecommunications and information exchange between systems Local and metropolitan area networks-Specific requirements - Part 11 : Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications Amendment: Enhancements for Extremely High Throughput (EHT)”, in the following denoted as “802.11 be Amendment”, a restricted TWT (R-TWT) was introduced. The R-TWT is based on a similar framework of scheduling STAs as the TWT, but also allows an AP to prioritize certain latency sensitive traffic flows. To protect the SP from other devices trying to access the medium a scheduling AP may signal a quiet interval with the same start time as the SP with a duration of one time unit (TU) (corresponding to 1024 ps). Further, R-TWT capable non- AP STAs must ensure that their TXOP (Transmit Opportunity) ends before an upcoming SP that they are not a member of. Similarly, such non-AP STAs cannot start new data transmissions that will not finish before the SP starts. As compared to the TWT of the 802.11 ax amendment, the R-TWT is based on broadcast TWT operation for setting up periodic SPs. An AP can set up such broadcast TWT operation by signaling a broadcast TWT information element in its beacon frame. Details concerning the possibilities of setting up a broadcast TWT operation are specified in the 802.11 ax Amendment.

[0009] The R-TWT functionality may for example provide benefits for UHR (Ultra High Reliability) applications. For example, EHT devices capable of operating on large bandwidths, such as 160 MHz or 320 MHz, may deliver their critical traffic in a timely manner using the R-TWT mechanism.

[0010] The use of R-TWT across several neighboring BSS is also being considered. Such mechanisms are also referred to as Multi-AP R-TWT mechanism. For example, in “Considerations for AP coordination in UHR: Coordinated Medium Access”, IEEE contribution IEEE 802.11-23 / 226r1 , by Abdel Karim Ajami et al., available online under “https: / / mentor.ieee.org / 802.11 / dcn / 23 / 11-23-0226-01-0uhr-coordination-of-r-twt-for-multi- ap-deployment.pptx” (2023) it is suggested to synchronize the R-TWT SP across neighboring BSSs. Two levels of synchronization are proposed. In the first, simpler, coordination mechanism only APs coordinate their medium access by ending their TXOPs before the other APs’ Coordinated SPs. In the second coordination mechanism not only the APs, but also the STAs within each BSS end their TXOP transmissions when an AP has scheduled a protected SP. However, known Multi-AP R-TWT mechanisms result in reservation of the full operating bandwidth of the BSS, which may be quite large, such as 160 MHz or even 320 MHz. On the other hand, there are certain device types, such as sensors and actuators for industrial applications, or various loT (Internet of Things) devices, that are not capable or not need to operate on very large bandwidths. While such devices may use the R-TWT mechanism to, e.g., provide timely feedback, their operation may be on a rather narrow bandwidth. For example, when assuming that a BSS uses a channel of 320 MHz bandwidth, it may be the case that only 20 MHz bandwidth is used to transmit critical data in the BSS, even if the R- TWT mechanism reserved the entire 320 MHz bandwidth for the SP. Accordingly, the R-TWT mechanism may result in inefficient resource usage. This problem arises mainly because all STAs in the BSS are expected to stay quiet during the R-TWT SP, unless they are explicitly permitted to participate. The inefficiency problem may become even worse if there are multiple neighboring BSSs operating using wide operating channels that have at least some overlap in frequency. In such cases the neighboring BSSs may be prevented from communicating during the scheduled R-TWT SP, even if there might be unused spectrum.

[0011] Accordingly, there is a need for techniques which allow for efficiently utilizing scheduled SPs.

[0012] Summary

[0013] According to an embodiment, a method of controlling wireless transmissions in a wireless communication system is provided. According to the method, an access point (AP) of the wireless communication system operates on a first wireless channel. The AP sends an indication of at least one scheduled service period (SP) for transmission of first data traffic of a group of one or more devices. The indication comprises information on frequency resources of the first wireless channel which are reserved for the first data traffic. Further, the AP participates in transmission of at least a part of the first data traffic on the reserved frequency resources.

[0014] According to a further embodiment, a method of controlling wireless transmissions in a wireless communication system is provided. According to the method, a wireless communication device receives, from an AP of the wireless communication system operating on a first wireless channel, an indication of at least one scheduled SP for transmission of first data traffic of a group of one or more devices. The indication comprises information on frequency resources of the first wireless channel which are reserved for the first data traffic. Based on the indication, the wireless communication device controls usage of the first wireless channel by the wireless communication device. According to a further embodiment, an AP for a wireless communication system is provided. The AP is configured to operate on a first wireless channel. Further, the AP is configured to send an indication of at least one scheduled SP for transmission of first data traffic of a group of one or more devices. The indication comprises information on frequency resources of the first wireless channel which are reserved for the first data traffic. Further, the AP is configured to participate in transmission of at least a part of the first data traffic on the reserved frequency resources.

[0015] According to a further embodiment, an AP for a wireless communication system is provided. The AP comprises at least one processor and a memory. The memory contains instructions executable by said at least one processor, whereby the AP is operative to operate on a first wireless channel. Further, the memory contains instructions executable by said at least one processor, whereby the AP is operative to send an indication of at least one scheduled SP for transmission of first data traffic of a group of one or more devices. The indication comprises information on frequency resources of the first wireless channel which are reserved for the first data traffic. Further, the memory contains instructions executable by said at least one processor, whereby the AP is operative to participate in transmission of at least a part of the first data traffic on the reserved frequency resources.

[0016] According to a further embodiment, a wireless communication device for a wireless communication system is provided. The wireless communication device is configured to receive, from an AP of the wireless communication system operating on a first wireless channel, an indication of at least one scheduled SP for transmission of first data traffic of a group of one or more devices. The indication comprises information on frequency resources of the first wireless channel which are reserved for the first data traffic. Further, the wireless communication device is configured to, based on the indication, control usage of the first wireless channel by the wireless communication device.

[0017] According to a further embodiment, a wireless communication device for a wireless communication system is provided. The wireless communication device comprises at least one processor and a memory. The memory contains instructions executable by said at least one processor, whereby the wireless device is operative to receive, from an AP of the wireless communication system operating on a first wireless channel, an indication of at least one scheduled SP for transmission of first data traffic of a group of one or more devices. The indication comprises information on frequency resources of the first wireless channel which are reserved for the first data traffic. Further, the memory contains instructions executable by said at least one processor, whereby the wireless communication device is operative to, based on the indication, control usage of the first wireless channel by the wireless communication device.

[0018] According to a further embodiment, a computer program or computer program product is provided, e.g., in the form of a non-transitory storage medium, which comprises program code to be executed by at least one processor of an AP of a wireless communication system. Execution of the program code causes the AP to operate on a first wireless channel. Further, execution of the program code causes the AP to send an indication of at least one scheduled SP for transmission of first data traffic of a group of one or more devices. The indication comprises information on frequency resources of the first wireless channel which are reserved for the first data traffic. Further, execution of the program code causes the AP to participate in transmission of at least a part of the first data traffic on the reserved frequency resources.

[0019] According to a further embodiment, a computer program or computer program product is provided, e.g., in the form of a non-transitory storage medium, which comprises program code to be executed by at least one processor of a wireless communication device for a wireless communication system. Execution of the program code causes the wireless communication device to receive, from an AP of the wireless communication system operating on a first wireless channel, an indication of at least one scheduled SP for transmission of first data traffic of a group of one or more devices. The indication comprises information on frequency resources of the first wireless channel which are reserved for the first data traffic. Further, execution of the program code causes the wireless communication device to, based on the indication, control usage of the first wireless channel by the wireless device.

[0020] Details of such embodiments and further embodiments will be apparent from the following detailed description.

[0021] Brief Description of the Drawings

[0022] Fig. 1 schematically illustrates a wireless communication system according to an embodiment.

[0023] Fig. 2 schematically illustrates an example of frequency-selective resource reservation in a scheduled SP in accordance with an embodiment of the present disclosure.

[0024] Fig. 3 schematically illustrates a further example of frequency-selective resource reservation in a scheduled SP in accordance with an embodiment of the present disclosure. Fig. 4 schematically illustrates a further example of frequency-selective resource reservation in a scheduled SP in accordance with an embodiment of the present disclosure.

[0025] Fig. 5 schematically illustrates an SP indication in accordance with an embodiment of the present disclosure.

[0026] Fig. 6 shows a flowchart for schematically illustrating a method according to an embodiment of the present disclosure.

[0027] Fig. 7 shows a flowchart for schematically illustrating a further method according to an embodiment of the present disclosure.

[0028] Fig. 8 schematically illustrates structures of an AP according to an embodiment of the present disclosure.

[0029] Fig. 9 schematically illustrates structures of a wireless device according to an embodiment of the present disclosure.

[0030] Detailed Description

[0031] In the following, concepts in accordance with exemplary embodiments of the invention will be explained in more detail and with reference to the accompanying drawings. The illustrated embodiments relate to controlling of wireless transmissions in a wireless communication system. The wireless communication system may be a WLAN system based on a IEEE 802.11 technology. However, it is noted that the illustrated concepts could also be applied to other wireless communication technologies, e.g., to contention-based modes of the LTE (Long Term Evolution) or NR (New Radio) technology specified by 3GPP (3rdGeneration Partnership Project).

[0032] In the illustrated concepts, one or more SPs are scheduled for transmissions on a wireless channel, i.e. , sending and / or receiving, of first data traffic of a group of one or more devices. The first data traffic is herein also denoted as member data traffic. The SP defines timefrequency resources which are reserved for the first data traffic. The SP may be scheduled by a TWT or R-TWT mechanism. However, depending on the utilized radio technology, other types of mechanisms which allow scheduling an SP for certain data traffic can be considered as well. The group may include wireless devices and / or APs. If a device is member of the group, i.e., is a member device, it is allowed to contend for access to the wireless channel during the SP. Other devices, i.e., non-member devices, should however refrain from attempting to transmit on the reserved time-frequency resources of the SP. In the timedimension, the reservation corresponds to the duration of the SP. In the frequency dimension, only certain frequency resources of the wireless channel may be reserved, and such reserved frequency resources are indicated in an SP indication. It may also be possible to reserve nonidentical frequency resources of the wireless channel for different SPs. In particular, if an AP operating on the wireless channel schedules one or more SPs for the first data traffic, it sends an SP indication which indicates the scheduled SP to other devices, typically by broadcasting the SP indication. In the R-TWT mechanism, the SP indication may for example correspond to the broadcasted R-TWT information. The SP indication indicates the timing of the SP(s), e.g., in terms of duration and / or period, and further indicates the frequency resources reserved for the first data traffic, e.g., in terms of the considered wireless channel, the utilized bandwidth, and one or more resource units (Rlls) reserved within this bandwidth. Devices which are not members of the group may therefore still contend for access to the wireless channel during the scheduled SP(s), however only on other frequency resources than those which are reserved for the first data traffic. Further, devices which are member of the group and intending to transmit the first data traffic should contend for access to the wireless channel during the scheduled SP(s) on the reserved frequency resources. For other data traffic than the first data traffic, herein also denoted as second data traffic or non-member data traffic, also the devices which are member of the group should contend for access to the wireless channel outside the scheduled SP(s) or, during the scheduled SP(s), on other frequency resources than those which are reserved for the first data traffic.

[0033] In the illustrated concepts, the R-TWT mechanism may thus be extended in such a way that the broadcasted R-TWT information also includes frequency information about the SP, allowing for SP reservation in both time and frequency. In this way, an R-TWT SP would not only start at a certain instant of time and last for a certain duration, but also be defined in the frequency dimension, e.g., to span only a fraction of the BSS operating bandwidth. In the present disclosure, such frequency selective R-TWT operation is also denoted as Subchannel Selective R-TWT (SS-R-TWT) operation.

[0034] Fig. 1 illustrates an exemplary wireless communication system according to an embodiment. In the illustrated example, the wireless communication system includes multiple APs 10, in the illustrated example referred to as AP1 , AP2, AP3, AP4, and multiple stations 20, in the illustrated example referred to as STA11 , STA12, STA13, STA21 , STA22, STA31 , and STA41. STA11 , STA12, and STA13 are served by AP1 , in a first BSS (Basic Service Set) denoted as BSS1. STA21 and STA22 are served by AP2, in a second BSS denoted as BSS2. STA31 is served by AP3, in a third BSS denoted as BSS3. STA41 is served by AP4, in a fourth BSS denoted as BSS4. The stations 20 may be non-AP STAs and correspond to various kinds of wireless devices, for example user terminals, such as mobile or stationary computing devices like smartphones, laptop computers, desktop computers, tablet computers, gaming devices, or the like. Further, the stations 20 could for example correspond to other kinds of equipment like smart home devices, printers, multimedia devices, data storage devices, or the like.

[0035] In the example of Fig. 1 , each of the stations 20 may connect through a radio link to one of the APs 10. For example, depending on location or channel conditions experienced by a given station 20, the station 20 may select an appropriate AP 10 and BSS for establishing the radio link. The radio link may be based on one or more OFDM carriers from a frequency spectrum which is shared on the basis of a contention-based mechanism, e.g., an unlicensed or licenseexempt band like the 2.4 GHz ISM (Industrial, Scientific and Medical) band, the 5 GHz band, the 6 GHz band, or the 60 GHz band.

[0036] Each AP 10 may provide data connectivity of the stations 20 connected to the AP 10. As further illustrated, the APs 10 may be connected to a data network (DN) 110. In this way, the APs 10 may also provide data connectivity between stations 20 connected to different APs 10. Further, the APs 10 may also provide data connectivity of the stations 20 to other entities, e.g., to one or more servers, service providers, data sources, data sinks, user terminals, or the like. Accordingly, the radio link established between a given station 20 and its serving AP 10 may be used for providing various kinds of services to the station 20, e.g., a voice service, a multimedia service, or other data service. Such services may be based on applications which are executed on the station 20 and / or on a device linked to the station 20. By way of example, Fig. 1 illustrates an application service platform 150 provided in the DN 110. The application(s) executed on the station 20 and / or on one or more other devices linked to the station 20 may use the radio link for data communication with one or more other stations 20 and / or the application service platform 150, thereby enabling utilization of the corresponding service(s) at the station 20. Further, it is noted that in some scenarios also direct radio links between stations 20 or radio links between the APs 10 could be utilized. The latter radio links could for example be used for forwarding data from one BSS to another BSS and / or for coordination of operation of the APs 10.

[0037] In accordance with the illustrated concepts one or more of the APs 10 may utilize an SS-R- TWT mechanism as outlined above. In this way, the AP 10 may coordinate usage of its operating wireless channel more efficiently, e.g., in view of increasing probability of successful channel access for critical data traffic. Such AP 10 would thus schedule one or more SPs for certain data traffic, e.g., critical data traffic, and indicate information concerning the scheduled SPs in broadcasted SS-R-TWT information. Such SS-R-TWT information would indicate timing, e.g., in terms of start time and duration, of the scheduled SP, and further also frequency resources of the wireless channel which are reserved for the SP, e.g., for the critical data traffic. Based on the SS-R-TWT information, a station 20 served by the AP 10 will know whether it is a member of the group of the corresponding SS-R-TWT agreement and control its usage of the wireless channel accordingly. For example, if it is a member of the group and needs to transmit the data traffic for which the SP was scheduled, it will contend for access to the reserved frequency resources within the SP. Otherwise, e.g., if a station 20 is not member of the group or needs to transmit other data traffic, it may contend for access to other frequency resources within the SP, or it may contend for access to the wireless channel outside the SP. Stations 20 served by other APs 10 or other APs 10 may act in a similar manner. In this way, it can be avoided that frequency resources are unnecessarily blocked and efficiency of spectrum usage improved.

[0038] Fig. 2 schematically shows an example for illustrating usage of the SS-R-TWT operation in a single BSS, denoted as BSS1. For example, this BSS could correspond to BSS1 of Fig. 1 , where the serving AP 10 is denoted by AP1. In the illustrated example, it is assumed that BSS1 operates on a wireless channel of 320 MHz bandwidth and that the 320 MHz bandwidth include four subchannels of 80 MHz bandwidth, denoted as SC1 , SC2, SC3, and SC4. As illustrated in Fig. 1 , AP1 serves three stations 20, namely STA11 , STA12 and STA13, in BSS1. It is further assumed that AP1 has recurring critical data traffic only to and / or from STA11 and that this data traffic is handled using the SS-R-TWT operation of the illustrated concepts, using only a part of the overall operating bandwidth, namely only a single subchannel of 80 MHz.

[0039] The SS-R-TWT operation may involve that AP1 sets up reoccurring SS-R-TWT SPs to serve STA11. As illustrated in Fig. 2, the SS-R-TWT SPs may be scheduled on SC4 to reoccur periodically every 10 ms and last for 1 ms. For this purpose, AP1 may broadcast corresponding SS-R-TWT information, e.g., in one or more beacons. Accordingly, already when setting up the SS-R-TWT SP, AP1 targets only a single subchannel, namely SC4, and informs its associated stations accordingly. Specifically, AP1 would inform STA11 , STA12, and STA13 that SS-R-TWT SPs dedicated to STA11 are planned to occur periodically only on SC4 and that the remaining three subchannels are free to be used for regular non-R-TWT traffic and are not restrcited by R-TWT related rules. As a result, STA12 and STA13 are allowed to use the remaining three subchannels in a relaxed manner for regular non-R-TWT traffic, and may access these remaining three subchannels in a regular manner, e.g., using contention based on the Enhanced Distributed Channel Access (EDCA) method of the IEEE 802.11 Standard. An example of such a relaxed operation is that STA12 and STA13 would be able to continue with their ongoing TXOPs or start new TXOPs in one or more of the remaining subchannels, without being further restricted by the SS-R-TWT scheduled on only SC4. The non-member devices of the scheduled SS-R-TWT SP, i.e., in the present example STA12 and STA13, may be provided with some additional information to help ensuring appropriate usage of the wireless channel. Such additional information may enable the non-member devices to align their transmissions with respect to end-time with the data traffic traffic of the member devices, in the illustrated example STA11. Such additional information could for example be an indication of planned transmission direction of the data traffic considered in the SP, i.e., whether the data traffic corresponds to downlink (DL) data traffic and / or to uplink (UL) data traffic, and a maximum allowed transmit duration. Based on such additional information, the non-member device could for example decide to access the three remaining subchannels only for UL data traffic and only for the maximum allowed transmit duration.

[0040] Within the overall operating bandwidth, the bandwidth portions not targeted by the SS-R-TWT SP, in the example of Fig. 2 the subchannels SC1 , SC2, and SC3, may be used in a flexible manner. Fo example, the remaining bandwidth portions could also be used for peer-to-peer communications between non-member devices, and such peer-to-peer communication may occur in parallel with the SS-R-TWT SPs.

[0041] Furthermore, if the AP scheduling the SS-R-TWT SP has advanced capabilities, such as support for sub-band (SBFD) full duplex operation, the AP could also support DL and / or UL communication in parallel with the SS-R-TWT SPs. In this way, the AP could serve non-AP STAs that are not members of the SS-R-TWT SP(s), using the bandwidth portions that are not targeted by the SS-R-TWT SP(s). For example, in the scenario underlying the example of Fig. 2, AP1 could use its SBFD capability to send DL data traffic to STA12 and / or STA13 during the SS-R-TWT scheduled for the critical data traffic of STA11. Here, it is noted that the SBFD operation would involve simultaneous transmitting and receiving on non-overlapping frequency resources of the same wirelesss channel. Such advanced capabilities of the AP can allow parallel DL and / or UL operations using different subchannels without requiring restrictions on start-time alignment and / or end-time alignment of the transmissions.

[0042] In some cases, e.g., if the AP is not capable of SBFD operation, the AP could also orchestrate trigger-based communication to ensure appropriate start time and / or end time and frequency separation of transmissions, e.g., using OFDMA (Orthogonal Frequency Division Multiple Access). Also in this way, the bandwidth portions not targeted by the SS-R-TWT SP can be efficiently used for regular DL data traffic and / or UL data traffic in parallel with the SS-R-TWT SPs.

[0043] Additionally, there may be some flexibility in terms of allowing some guard band between the bandwidth portions targeted by the SS-R-TWT SP and the remaining bandwidth portions of the operating bandwidth. For example, in the example of Fig. 2, the AP1 could indicate in the SS-R-TWT information that only SC4 is reserved for the member data traffic of the SS-R-TWT SP, but only the first subchannel (SC1) and the second subchannel (SC2) are allowed to be used for non-member data traffic, keeping the third subchannel (SC3) as guard band, i.e., empty. Accordingly, spectral separation of the member data traffic and of the non-member data traffic can be achieved. Such spectral separation may for example be beneficial for reliable SBFD operation of the AP.

[0044] A specific example of SS-R-TWT operation as illustrated in the example of Fig. 2 may thus involve the following:

[0045] - In a first SS-R-TWT SP scheduled for STA11 , in the figure denoted as SP1 , and targeting SC4, STA12 and STA13 may use the remaining subchannels (SC1 , SC2, and / or SC3) for peer-to-peer communication among them. Further, if the AP1 is capable of SBFD operation, STA12 and / or STA13 may communicate DL data traffic and / or UL data traffic with AP1 in parallel with SP1.

[0046] - In a second SS-R-TWT SP scheduled for STA11 , in the figure denoted as SP2, and targeting SC4, STA12 and / or STA13 may continue an ongoing TXOP that does not involve SC4.

[0047] - At the beginning of a third SS-R-TWT SP scheduled for STA11 , in the figure denoted as SP3, and targeting SC4, a previously started TXOP owned by STA12 or STA13 and spanning the full operating bandwidth is ended to ensure AP1 can start SP3 as planned. If AP1 is not full duplex capable, AP1 could use frequency multiplexing, e.g., using OFDMA, to serve STA12 and STA13 in parallel during the TXOP.

[0048] As can be seen from this example, by only reserving a part of the operating bandwidth for the SS-R-TWT SPs, AP1 can improve the performance in its BSS by allowing the remaining frequency resources to be used in parallel for various types of communications.

[0049] The SS-R-TWT operation of the illustrated concepts may also be beneficial for performance across multiple BSSs. This is further demonstrated by examples as illustrated by Figs. 3 and 4.

[0050] In the example of Fig. 3, it is assumed that there are two neighoring APs with largely overlapping service areas, denoted as AP1 and AP2. These APs may for example correspond to AP1 and AP2 of Fig. 1 , which serve BSSs denoted as BSS1 and BSS2. These APs may agree to coordinate their respective SS-R-TWT SPs. Further, it is assumed that both APs operate on the same wireless channel of 320 MHz bandwidth. Similar to the example of Fig. 2, the wireless channel includes four subchannels of 80 MHz bandwidth, denoted as SC1 , SC2, SC3, and SC4. It is noted that similar considerations as explained in the following would also apply if the APs would use operating bandwidths which are only partly overlapping. Using the conventional R-TWT mechanism, an R-TWT SP reserved by one of the APs would result in protection of the entire 320 MHz operating bandwidth for the duration of the SP.

[0051] In the illustrated concepts, the SS-R-TWT SP however targerts only a certain part of the operating bandwidth, which is indicated by the SS-R-TWT information, e.g., broadcasted in a beacon transmitted by the AP scheduling the SS-R-TWT. In the example of Fig. 3, it is assumed that AP1 schedules an SS-R-TWT which targets only the fourth subchannel (SC4), reoccurs evry 10 ms, and has a duration of 1 ms. By the SS-R-TWT information, AP1 informs its associated stations accordingly. Further, the SS-R-TWT information also accordingly informs AP2 and its associated stations. In some scenarios, stations associated with AP2 may directly receive the SS-R-TWT information sent by AP1. In other cases, the SS-R-TWT information may be further distributed by AP2 to the stations in BSS2. As a result, the operations in BSS2 are performed in such a way that the bandwidth portion targeted by the SS-R-TWT SP scheduled by AP1 , i.e., SC4, remains protected during the SS-R-TWT SP. For example, this may involve that there is no traffic in BSS2 on the targeted bandwidth portions during the SS-R-TWT. On the other hand, operations in the bandwidth portions not targeted by the SS-R-TWT SP scheduled by AP1 , i.e., SC1 , SC2, and SC3, remain possible in both BSS1 and BSS2. Such operations may for example involve that a non-member device or a member device that needs to transmit non-member data traffic access these remaining three subchannels in a regular manner, e.g., using contention based on the EDCA method of the IEEE 802.11 Standard.

[0052] As further illustrated in Fig. 3, the actual SS-R-TWT SPs may be preceded by an indication which causes devices to refrain from transmitting on the bandwidth portion targeted by the SS-R-TWT. Such indication may for example correspond to a Quiet Element (QE) of the IEEE 802.11 Standard, which would also be considered by devices which have no dedicated support for the SS-R-TWT of the illustrated concepts.

[0053] The limitation of the SS-R-TWT to a portion of the operating bandwidth may be indicated already when setting up an SS-R-TWT agreement, for example by using beacons. Accordingly, when setting up the SS-R-TWT agreement, AP1 may inform its associated stations and AP2 that its SS-R-TWT SPs are setup on the 320 MHz operating channel, but will target only specific sub-portion(s) of the operating bandwidth. Alternatively, the targeted bandwidth portions may be indicated when AP1 reserves the wireless channel for the SS-R- TWT. The latter option may provide the benefit that AP1 may dynamically decide how much bandwidth to use for each SS-R-TWT SP without reserving it in advance. This may for example be beneficial for serving event-based traffic in DL and / or UL. Fig. 4 illustrates a corresponding example. The example of Fig. 4 is generally similar to that of Fig. 3, but involve dynamically setting the protected bandwidth portions for each SS-R-TWT SP, which may be done taking into account the current bandwidth demand for the member data traffic of the SS-R-TWT.

[0054] In the example of Fig. 4, AP1 uses 80 MHz (SC4) for its first R-TWT SP, while it uses 160 MHz (SC3 and SC4) and 320 MHz (SC1 , SC2, SC3 and SC4) for the second and the third R- TWT SP. Non-R-TWT data traffic in both BSS1 and BSS2 are accordingly adapted as illustrated.

[0055] In a variant, the dynamic indication of the targeted bandwidth portions as explained in connection with Fig. 4 could also be combined with a previous initial indication of candidate targeted bandwidth portions, e.g., provided when setting up the SS-R-TWT agreement. For example, AP1 could first indicate that SC2, SC3, and SC4 are candidates for being reserved in a SS-R-TWT SP, and a final selection among these subchannels could then be performed for each individual SS-R-TWT SP.

[0056] In some scenarios, the selection of the targeted bandwidth portions of an SS-R-TWT may also consider the primary 20 MHz subchannel of the BSS in which the SS-R-TWT is being scheduled and / or the respective primary 20 MHz subchannel of one or more neighboring BSSs. In this way, it can be taken into account that certain devices, in particular legacy devices that support only the IEEE 802.11 be Amendment or earlier versions of the IEEE 802.11 Standard, can only transmit if the primary 20 MHz subchannel of the BSS is idle.

[0057] For example, if the SS-R-TWT operation of the illustrated concepts is being used within a single BSS and if there are legacy STAs present, then the serving AP may set up the SS-R- TWT SPs to target only bandwidth portions that do not include the primary 20 MHz subchannel, thereby enebling also legacy devices to transmit in parallel with these SS-R-TWT SPs. For example, if the BSS operating bandwidth is 80 MHz, and there are legacy STAs present, the serving AP may set up the SS-R-TWT SPs on bandwidth portions up to 60 MHz, by excluding the primary 20 MHz subchannel. If need arises to quiet the legacy devices to ensure that channel access can be gained on the desired bandwidth portions at the planned time instances, existing mechanisms of the IEEE 802.11 Standard can be utilized, such as transmission of a QE.

[0058] If the SS-R-TWT operation of the illustrated concepts is being used in a coordinated manner across multiple BSSs, the APs serving the BSSs may coordinate the set up of the corresponding SS-R-TWT SPs in such a way that primary 20 MHz channels of all coordinating BSSs are excluded from the targeted bandwdiths of the SS-R-TWT SPs. The SS-R-TWT operation of the illustrated concepts may be enabled by extending the R-TWT- signaling of the IEEE 802.11 be Amendment. Specifically, the Broadcast TWT Info subfield of the Broadcast TWT Parameter Set field in a TWT request or TWT response may be supplemented by information on the frequency resources reserved for the SS-R-TWT SP, i.e., the targeted bandwidth portions. A corresponding example format of the Broadcast TWT Information is illustrated in Fig. 5.

[0059] In the example of Fig. 5, a “Frequency and Bandwidth Information” field is added to the Broadcast TWT Info subfield. By means of this additional field, information on the targeted bandwidth portions of an SS-R-TWT SP may be communicated between devices in the same BSS and / or across APs in Multi-AP coordination scenarios.

[0060] The “Frequency and Bandwidth Information” field may indicate the wireless channel on which the SS-R-TWT is being scheduled, e.g., in terms of a channel identifier. Alternatively or in addition, the “Frequency and Bandwidth Information” field may indicate the bandwidth of the wireless channel, e.g., in terms of a bandwidth indentifier. “Frequency and Bandwidth Information” field may indicate the specific reserved frequency resources, e.g., in terms of one or more Rll identifiers.

[0061] In addition, the “Frequency and Bandwidth Information” field may be supplemented with various additional information, e.g., an indication of whether the SS-R-TWT is scheduled for UL data traffic, for DL data traffic, and / or for data traffic between APs, one or more timing indications, e.g., for start-time alignment or end-time alignment, an indication of an SB-FD capability or other FD capability of the AP scheduling the SS-R-TWT SP, an indication of a channel access mode for the member data traffic of the SS-R-TWT SP, and / or an indication of a channel access mode for the non-member data traffic of the SS-R-TWT SP.

[0062] Fig. 6 shows a flowchart for illustrating a method of controlling wireless transmissions in a wireless communication system, which may be utilized for implementing the illustrated concepts. The method of Fig. 6 may be used for implementing the illustrated concepts in an AP of a wireless communication system, e.g., one of the above-mentioned APs 10. The wireless communication system may be based on a wireless local area network, WLAN, technology, e.g., according to the IEEE 802.11 standards family.

[0063] If a processor-based implementation of the AP is used, at least some of the steps of the method of Fig. 6 may be performed and / or controlled by one or more processors of the AP. Such AP may also include a memory storing program code for implementing at least some of the below described functionalities or steps of the method of Fig. 6. At step 610, the AP operates on a first wireless channel. For example, the AP may use the first wireless channel to serve a number of associated wireless devices in a first BSS.

[0064] At step 620, the AP sends an indication of at least one scheduled SP for transmission of first data traffic of a group of one or more devices, e.g., wireless devices associated with the AP. The indication comprises information on frequency resources of the first wireless channel which are reserved for the first data traffic. The above-mentioned SS-R-TWT is an example of such scheduled SP. If the indication indicates multiple scheduled SPs for transmission of the first data traffic, the frequency resources reserved for the first data traffic may differ between at least some of these multiple SPs.

[0065] The information may indicate a subchannel of the first wireless channel, and the subchannel may be reserved for the first data traffic of the group. The subchannel may be different from a primary subchannel of the AP, in particular different from a primary 20 MHz subchannel of a BSS served by the AP.

[0066] The indication may be receivable by a further AP of the wireless communication system. The further AP may operate on a second wireless channel which at least partially overlaps in frequency with the first wireless channel. In such case, the subchannel may be different from a primary subchannel of the further AP, in in particular different from a primary 20 MHz subchannel of a BSS served by the further AP.

[0067] In some scenarios, the information may comprise an indication of the first wireless channel. Alternatively or in addition, the information may comprise an indication of a bandwidth of the first wireless channel. Alternatively or in addition, the information comprises an indication of one or more Rlls of the first wireless channel, in particular of one or more Rlls corresponding to the reserved frequency resources.

[0068] In some scenarios, the information may comprise an indication that the at least one SP applies to DL data traffic from the AP. Alternatively or in addition, the information may comprise an indication that the at least one SP applies to UL data traffic to the AP. Alternatively or in addition, the information may comprise an indication that the at least one SP applies to data traffic between wireless devices. One or more of these wireless devices could be associated with the AP. Alternatively or in addition, the information may comprise an indication that the at least one SP applies to data traffic between the AP and another AP. If the indication indicates multiple scheduled SPs for transmission of the first data traffic, these multiple SPs may apply to different combinations of these types of data traffic, e.g., one or more of the multiple SPs could apply to DL data traffic from the AP, one or more of the multiple SPs could apply to UL data traffic to the AP, one or more of the multiple SPs could apply to data traffic between wireless devices, and / or one or more of the multiple SPs could apply to data traffic between the AP and another AP.

[0069] In some scenarios, the information may comprise an indication of required frequency separation of the reserved frequency resources from other frequency resources of the first wireless channel, e.g., to provide a guard band. The other frequency resources may for example be used for data traffic without reservation, e.g., for the above-mentioned nonmember data traffic.

[0070] In some scenarios, the information may comprise an indication of an FD capability of the AP, in particular an indication of an SBFD capability of the AP.

[0071] In some scenarios, the information may comprise an indication of a channel access mode for the reserved frequency resources of the first wireless channel. Alternatively or in addition, the information may comprise an indication of a channel access mode for other frequency resources of the first wireless channel. The channel access mode may for example involve contention-based access, e.g., using the EDCA method, or trigger-based access.

[0072] At step 630, the AP participates in transmission of at least a part of the first data traffic on the reserved frequency resources. This may for example involve sending at least a part of the first data traffic and / or receiving at least a part of the first data traffic.

[0073] Fig. 7 shows a flowchart for illustrating a method of controlling wireless transmissions in a wireless communication system, which may be utilized for implementing the illustrated concepts. The method of Fig. 7 may be used for implementing the illustrated concepts in wireless communication device for operation in a wireless communication system, e.g., one of the above-mentioned STAs 20 or in one of the above-mentioned APs 10. The wireless communication system may be based on a wireless local area network, WLAN, technology, e.g., according to the IEEE 802.11 standards family.

[0074] If a processor-based implementation of the wireless communication device is used, at least some of the steps of the method of Fig. 7 may be performed and / or controlled by one or more processors of the wireless communication device. Such wireless communication device may also include a memory storing program code for implementing at least some of the below described functionalities or steps of the method of Fig. 7. At step 710, the wireless communication device receives, from an AP of the wireless communication system operating on a first wireless channel, an indication of at least one scheduled SP for transmission of first data traffic of a group of one or more devices. The indication comprises information on frequency resources of the first wireless channel which are reserved for the first data traffic. The AP may for example correspond to one of the above- mentioned APs 10. The wireless communication device may be a wireless device associated with the AP or another AP of the wireless communication system. If the indication indicates multiple scheduled SPs for transmission of the first data traffic, the frequency resources reserved for the first data traffic may differ between at least some of these multiple SPs.

[0075] The information may indicate a subchannel of the first wireless channel, and the subchannel may be reserved for the first data traffic of the group. The subchannel may be different from a primary subchannel of the AP, in particular different from a primary 20 MHz subchannel of a BSS served by the AP.

[0076] The indication may be receivable by a further AP of the wireless communication system. The further AP may operate on a second wireless channel which at least partially overlaps in frequency with the first wireless channel. In such case, the subchannel may be different from a primary subchannel of the further AP, in in particular different from a primary 20 MHz subchannel of a BSS served by the further AP.

[0077] In some scenarios, the information may comprise an indication of the first wireless channel. Alternatively or in addition, the information may comprise an indication of a bandwidth of the first wireless channel. Alternatively or in addition, the information comprises an indication of one or more Rlls of the first wireless channel, in particular of one or more Rlls corresponding to the reserved frequency resources.

[0078] In some scenarios, the information may comprise an indication that the at least one SP applies to DL data traffic from the AP. Alternatively or in addition, the information may comprise an indication that the at least one SP applies to UL data traffic to the AP. Alternatively or in addition, the information may comprise an indication that the at least one SP applies to data traffic between wireless devices. One or more of these wireless devices could be associated with the AP. Alternatively or in addition, the information may comprise an indication that the at least one SP applies to data traffic between the AP and another AP. If the indication indicates multiple scheduled SPs for transmission of the first data traffic, these multiple SPs may apply to different combinations of these types of data traffic, e.g., one or more of the multiple SPs could apply to DL data traffic from the AP, one or more of the multiple SPs could apply to UL data traffic to the AP, one or more of the multiple SPs could apply to data traffic between wireless devices, and / or one or more of the multiple SPs could apply to data traffic between the AP and another AP.

[0079] In some scenarios, the information may comprise an indication of required frequency separation of the reserved frequency resources from other frequency resources of the first wireless channel, e.g., to provide a guard band. The other frequency resources may for example be used for data traffic without reservation, e.g., for the above-mentioned nonmember data traffic.

[0080] In some scenarios, the information may comprise an indication of an FD capability of the AP, in particular an indication of an SBFD capability of the AP.

[0081] In some scenarios, the information may comprise an indication of a channel access mode for the reserved frequency resources of the first wireless channel. Alternatively or in addition, the information may comprise an indication of a channel access mode for other frequency resources of the first wireless channel. The channel access mode may for example involve contention-based access, e.g., using the EDCA method, or trigger-based access.

[0082] At step 720, the wireless communication device controls, based on the information obtained at step 710, usage of the first wireless channel by the wireless communication device. This may for example involve that, in response to the wireless communication device being member of the group, the wireless communication device participates in transmission of at least a part of the first data traffic on the reserved frequency resources, as indicated by step 730. Alternatively or in addition, step 720 involve that, in response to the wireless communication device being member of the group and having a need to transmit second data traffic, the wireless device contends for access to other frequency resources of the first wireless channel to transmit the second data traffic to the AP. Alternatively or in addition, step 720 involve that, in response to the wireless communication device not being member of the group, the wireless communication device contends for access to other frequency resources of the first wireless channel to transmit third data traffic.

[0083] Fig. 8 illustrates a processor-based implementation of an AP 800. The structures as illustrated in Fig. 8 may be used for implementing the above-described concepts. The AP 800 may for example correspond to one of above-mentioned APs 10.

[0084] As illustrated, the AP 800 includes a radio interface 810. The radio interface 810 may for example be based on a WLAN technology, e.g., according to an IEEE 802.11 family standard. However, other wireless technologies could be supported as well, e.g., the LTE technology or the NR technology. Further, the AP 800 is provided with a network interface 820 for connecting to a data network, e.g., using a wire-based connection.

[0085] Further, the AP 800 may include one or more processors 850 coupled to the interfaces 810, 820, and a memory 860 coupled to the processor(s) 850. By way of example, the interfaces 810, 820, the processor(s) 850, and the memory 860 could be coupled by one or more internal bus systems of the AP 800. The memory 860 may include a Read-Only-Memory (ROM), e.g., a flash ROM, a Random Access Memory (RAM), e.g., a Dynamic RAM (DRAM) or Static RAM (SRAM), a mass storage, e.g., a hard disk or solid state disk, or the like. As illustrated, the memory 860 may include software 870 and / or firmware 880. The memory 860 may include suitably configured program code to be executed by the processor(s) 850 so as to implement the above-described functionalities for controlling wireless transmissions, such as explained in connection with the method of Fig. 6 or in connection with the method of Fig. 7.

[0086] It is to be understood that the structures as illustrated in Fig. 8 are merely schematic and that the AP 800 may actually include further components which, for the sake of clarity, have not been illustrated, e.g., further interfaces or further processors. Also, it is to be understood that the memory 860 may include further program code for implementing known functionalities of an AP in an IEEE 802.11 standard compliant technology. According to some embodiments, also a computer program may be provided for implementing functionalities of the AP 800, e.g., in the form of a physical medium storing the program code and / or other data to be stored in the memory 860 or by making the program code available for download or by streaming.

[0087] Fig. 9 illustrates a processor-based implementation of wireless device 900. The structures as illustrated in Fig. 9 may be used for implementing the above-described concepts. The wireless device 900 may for example correspond to one of above-mentioned stations 20.

[0088] As illustrated, the wireless device 900 includes a radio interface 910. The radio interface 910 may for example be based on a WLAN technology, e.g., according to an IEEE 802.11 family standard. However, other wireless technologies could be supported as well, e.g., the LTE technology or the NR technology.

[0089] Further, the wireless device 900 may include one or more processors 950 coupled to the radio interface 910 and a memory 960 coupled to the processor(s) 950. By way of example, the radio interface 910, the processor(s) 950, and the memory 960 could be coupled by one or more internal bus systems of the wireless device 900. The memory 960 may include a ROM, e.g., a flash ROM, a RAM, e.g., a DRAM or SRAM, a mass storage, e.g., a hard disk or solid state disk, or the like. As illustrated, the memory 960 may include software 970 and / or firmware 980. The memory 960 may include suitably configured program code to be executed by the processor(s) 950 so as to implement the above-described functionalities for controlling wireless transmissions, such as explained in connection with the method of Fig. 7.

[0090] It is to be understood that the structures as illustrated in Fig. 9 are merely schematic and that the wireless device 900 may actually include further components which, for the sake of clarity, have not been illustrated, e.g., further interfaces or further processors. Also, it is to be understood that the memory 960 may include further program code for implementing known functionalities of STA in an IEEE 802.11 standard compliant technology. According to some embodiments, also a computer program may be provided for implementing functionalities of the wireless device 900, e.g., in the form of a physical medium storing the program code and / or other data to be stored in the memory 960 or by making the program code available for download or by streaming.

[0091] As can be seen, the concepts as described above may be used for using scheduled SPs in a resource efficient manner, by avoiding blocking excessively large bandwidth portions from being used by other devices, which are not allowed to participate in the SP, or for other data traffic. The proposed SS-R-TWT operation results in better spectrum utilization in cases where R-TWT mechanism is needed for timely delivery of critical traffic, which would not use the full available operating bandwidth of the AP for delivery. Within a single BSS, such a benefit may be significant when the operating bandwidth in the BSS is large, e.g., 320 MHz, and the STAs using the R-TWT mechanism for delivery of critical data traffic operate on smaller bandwidth than the full operating bandwidth of the AP or when the packet sizes of the critical traffic can be more efficiently handlerd when using a smaller bandwidth than the full operating bandwidth of the AP. In scenarios where APs are densely deployed, the illustrated concepts can provide further benefits, because excessive protection of frequency resources of the SP across multiple BSSs can be avoided. This, in turn, provides the possibility to manage allocation of SP resources among the APs in a more efficient manner, by using a smaller frequency granularity for the allocation.

[0092] It is to be understood that the examples and embodiments as explained above are merely illustrative and susceptible to various modifications. For example, the illustrated concepts may be applied in connection with various kinds of wireless technologies, without limitation to WLAN technologies. Further, the illustrated concepts may be applied with respect to various categories of data traffic. Moreover, it is to be understood that the above concepts may be implemented by using correspondingly designed software to be executed by one or more processors of an existing device or apparatus, or by using dedicated device hardware. Further, it should be noted that the illustrated apparatuses or devices may each be implemented as a single device or as a system of multiple interacting devices or modules.

Claims

Claims1. A method of controlling wireless transmissions in a wireless communication system, the method comprising: an access point (10; 800) of the wireless communication system operating on a first wireless channel; the access point (10; 800) sending an indication of at least one scheduled service period for transmission of first data traffic of a group of one or more devices (10, 20; 800, 900), the indication comprising information on frequency resources of the first wireless channel which are reserved for the first data traffic; and the access point (10; 800) participating in transmission of at least a part of the first data traffic on the reserved frequency resources.

2. The method according to claim 1 , wherein the information indicates a subchannel of the first wireless channel, the subchannel being reserved for the first data traffic of the group.

3. The method according to claim 2, wherein the subchannel is different from a primary subchannel of the access point.

4. The method according to claim 2 or 3, wherein the indication is receivable by a further access point of the wireless communication system, the further access point operating on a second wireless channel which at least partially overlaps in frequency with the first wireless channel, and wherein the subchannel is different from a primary subchannel of the further access point.

5. The method according to any of claims 1 to 4, wherein the information comprises an indication of the first wireless channel.

6. The method according to any of claims 1 to 5, wherein the information comprises an indication of a bandwidth of the first wireless channel.

7. The method according to any of claims 1 to 6, wherein the information comprises an indication of one or more resource units of the first wireless channel.

8. The method according to any of claims 1 to 7,wherein the information comprises an indication that the at least one service period applies to downlink data traffic from the access point (10; 800).

9. The method according to any of claims 1 to 8, wherein the information comprises an indication that the at least one service period applies to uplink data traffic to the access point (10; 800).

10. The method according to any of claims 1 to 9, wherein the information comprises an indication that the at least one service period applies to data traffic between the wireless devices (20; 900).

11. The method according to any of claims 1 to 10, wherein the information comprises an indication that the at least one service period applies to data traffic between the access point (10; 800) and another access point (10; 800).

12. The method according to any of claims 1 to 11 , wherein the information comprises an indication of required frequency separation of the reserved frequency resources from other frequency resources of the first wireless channel.

13. The method according to any of claims 1 to 12, wherein the information comprises an indication of a full-duplex capability of the access point (10; 800).

14. The method according to any of claims 1 to 13, wherein the information comprises an indication of a channel access mode for the reserved frequency resources of the first wireless channel.

15. The method according to any of claims 1 to 14, wherein the information comprises an indication of a channel access mode for other frequency resources of the first wireless channel.

16. The method according to any one of claims 1 to 15, wherein the wireless communication system is based on a Wireless Local Area Network technology according to the IEEE 802.11 standards family.

17. A method of controlling wireless transmissions in a wireless communication system, the method comprising:a wireless communication device (10, 20; 800; 900) receiving, from an access point (10; 800) of the wireless communication system operating on a first wireless channel, an indication of at least one scheduled service period for transmission of first data traffic of a group of one or more devices (10, 20; 800, 900), the indication comprising information on frequency resources of the first wireless channel which are reserved for the first data traffic; and based on the indication, the wireless communication device (10, 20; 800; 900) controlling usage of the first wireless channel by the wireless communication device (10, 20; 800; 900).

18. The method according to claim 17, comprising: in response to the wireless communication device (10, 20; 800; 900) being member of the group, the wireless communication device (10, 20; 800; 900) participating in transmission of at least a part of the first data traffic on the reserved frequency resources.

19. The method according to claim 17 or 18, comprising: in response to the wireless communication device (10, 20; 800; 900) being member of the group and a need to transmit second data traffic, the wireless communication device (10, 20; 800; 900) contending for access to other frequency resources of the first wireless channel to transmit the second data traffic to the access point (10; 800).

20. The method according to any of claim 17 to 19, comprising: in response to the wireless communication device (10, 20; 800; 900) not being member of the group, the wireless communication device (10, 20; 800; 900) contending for access to other frequency resources of the first wireless channel to transmit third data traffic.

21. The method according to any of claims 17 to 20, wherein the information indicates a subchannel of the first wireless channel, the subchannel being reserved for the first data traffic of the group.

22. The method according to claim 21 , wherein the subchannel is different from a primary subchannel of the access point.

23. The method according to claim 21 or 22, wherein the indication is receivable by a further access point (10; 800) of the wireless communication system, the further access point (10; 800) operating on a second wireless channel which at least partially overlaps in frequency with the first wireless channel, and wherein the subchannel is different from a primary subchannel of the further access point(10; 800) .

24. The method according to any of claims 17 to 23, wherein the information comprises an indication of the first wireless channel.

25. The method according to any of claims 17 to 24, wherein the information comprises an indication of a bandwidth of the first wireless channel.

26. The method according to any of claims 17 to 25, wherein the information comprises an indication of one or more resource units of the first wireless channel.

27. The method according to any of claims 17 to 26, wherein the information comprises an indication that the at least one service period applies to downlink data traffic from the access point (10; 800).

28. The method according to any of claims 17 to 27, wherein the information comprises an indication that the at least one service period applies to uplink data traffic to the access point (10; 800).

29. The method according to any of claims 17 to 28, wherein the information comprises an indication that the at least one service period applies to data traffic between wireless devices (20; 900).

30. The method according to any of claims 17 to 29, wherein the information comprises an indication that the at least one service period applies to data traffic between the access point (10; 800) and another access point (10; 800).

31. The method according to any of claims 17 to 30, wherein the information comprises an indication of required frequency separation of the reserved frequency resources from other frequency resources of the first wireless channel.

32. The method according to any of claims 17 to 31 , wherein the information comprises an indication of a full-duplex capability of the access point (10; 800).

33. The method according to any of claims 17 to 32, wherein the information comprises an indication of a channel access mode for the reserved frequency resources of the first wireless channel.

34. The method according to any of claims 17 to 33, wherein the information comprises an indication of a channel access mode for other frequency resources of the first wireless channel.

35. The method according to any of emodiments 17 to 34, wherein the wireless communication device is a wireless device associated with the access point (10; 800).

36. The method according to any of claims 17 to 34, wherein the wireless communication device is another access point (10; 800) of the wireless communication system.

37. The method according to any one of claims 17 to 36, wherein the wireless communication system is based on a Wireless Local Area Network technology according to the IEEE 802.11 standards family.

38. An access point (10; 800) for a wireless communication system, the access point (10; 800) being configured to:- operate on a first wireless channel;- send an indication of at least one scheduled service period for transmission of first data traffic of a group of one or more devices, the indication comprising information on frequency resources of the first wireless channel which are reserved for the first data traffic; and- participate in transmission of at least a part of the first data traffic on the reserved frequency resources.

39. The access point (10; 800) according to claim 38, wherein the access point (10; 800) is configured to perform a method according to any one of claims 2 to 16.

40. The access point (10; 800) according to claim 38 or 39, comprising: at least one processor (850), and a memory (860) containing program code executable by the at least one processor (850), whereby execution of the program code by the at least one processor (850) causes the access point (10; 800) to perform a method according to any one of claims 1 to 16.41 . A wireless communication device (10, 20; 800; 900) for a wireless communication system, the wireless communication device (10, 20; 800; 900) being configured to:- receive, from an access point (10; 800) of the wireless communication system operating on a first wireless channel, an indication of at least one scheduled service period for transmission of first data traffic of a group of one or more devices, the indication comprising information on frequency resources of the first wireless channel which are reserved for the first data traffic; and- based on the indication, control usage of the first wireless channel by the wireless communication device (10, 20; 800; 900).

42. The wireless communication device (10, 20; 800; 900) according to claim 41 , wherein the wireless communication device (10, 20; 800; 900) is configured to perform a method according to any one of claims 18 to 37.

43. The wireless communication device (10, 20; 800; 900) according to claim 41 or 42, comprising: at least one processor (850; 950), and a memory (860; 960) containing program code executable by the at least one processor (850; 950), whereby execution of the program code by the at least one processor (850; 950) causes the wireless communication device (10, 20; 800; 900) to perform a method according to any one of claims 17 to 37.

44. A computer program or computer program product comprising program code to be executed by at least one processor (850) of an access point (10; 800), whereby execution of the program code causes the access point (10; 800) to perform a method according to any one of claims 1 to 16.

45. A computer program or computer program product comprising program code to be executed by at least one processor (850, 950) of a wireless communication device (10, 20; 800; 900), whereby execution of the program code causes the wireless communication device (10, 20; 800; 900) to perform a method according to any one of claims 17 to 37.

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