Using a primary communication channel and a secondary communication channel in a wireless communication system

Abstract

The present subject matter relates to a method (301) comprising: receiving by a third apparatus (STA3), from a first apparatus (AP1), a notification to, after a time window has elapsed, further use a corresponding secondary communication channel of a wireless communication system or switch to a primary communication channel of the wireless communication system for communication with the first apparatus; wherein the third apparatus (STA3) is configured to communicate, during the time window, with the first apparatus (AP1) the corresponding secondary communication channel and the first apparatus is configured to communicate with a second apparatus (STA2) on the primary communication channel. Apparatuses to perform the methods are also disclosed.

Description

[0001] USING A PRIMARY COMMUNICATION CHANNEL AND A SECONDARY COMMUNICATION CHANNEL IN A WIRELESS COMMUNICATION SYSTEM

[0002] Technical Field

[0003] Various example embodiments relate to telecommunication systems, and more particularly to communication using a primary communication channel and a secondary communication channel.

[0004] Background

[0005] Efficient communication scheduling may be of interest for optimizing wireless network performance, particularly in reducing contention delays and improving resource utilization. Transmission Opportunity (TXOP)-based access may be one such mechanism, as it may allow a station to transmit for a defined duration without contention, improving transmission efficiency. However, these mechanisms may introduce limitations, such as increased latency, restricted flexibility in dynamic traffic scenarios, and potential inefficiencies in resource allocation when traffic demand fluctuates.

[0006] Summary

[0007] Example embodiments provide an apparatus, referred to as first apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus at least to: set a time window during which the first apparatus is configured to communicate with a second apparatus on a primary communication channel of a wireless communication system and to communicate with a third apparatus on a corresponding secondary communication channel of the wireless communication system; and notify the third apparatus to, after the time window has elapsed, further use the corresponding secondary communication channel or switch to the primary communication channel for communication.

[0008] Example embodiments provide a method comprising: setting by a first apparatus a time window during which the first apparatus is configured to communicate with a secondapparatus on a primary communication channel of a wireless communication system and to communicate with a third apparatus on a corresponding secondary communication channel of the wireless communication system; and notifying, by the first apparatus, the third apparatus to, after the time window has elapsed, further use the corresponding secondary communication channel or switch to the primary communication channel for communication.

[0009] Example embodiments provide an apparatus, referred to as third apparatus; the third apparatus comprising at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the third apparatus at least to: receive from a first apparatus, a notification to, after a time window has elapsed, further use a corresponding secondary communication channel of a wireless communication system or switch to a primary communication channel of the wireless communication system for communication with the first apparatus; wherein, during the time window, the third apparatus is configured to communicate with the first apparatus on the corresponding secondary communication channel and the first apparatus is configured to communicate with a second apparatus on the primary communication channel.

[0010] Example embodiments provide a method, comprising: receiving by a third apparatus, from a first apparatus, a notification to, after a time window has elapsed, further use a corresponding secondary communication channel of a wireless communication system or switch to a primary communication channel of the wireless communication system for communication with the first apparatus; wherein the third apparatus is configured to communicate, during the time window, with the first apparatus on the corresponding secondary communication channel and the first apparatus is configured to communicate with a second apparatus on the primary communication channel.

[0011] Example embodiments provide an apparatus, referred to as first apparatus, the first apparatus comprising at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus at least to: determine that a communication process on a secondary communication channel, of a wireless communication system, between the first apparatus and a third apparatus terminates during a time window; wherein during the time window the first apparatus is configured to communicate with a second apparatus on a primarycommunication channel of the wireless communication system and to communicate with the third apparatus on the secondary communication channel; and instruct the third apparatus to switch to the primary communication channel before the end of the time window.

[0012] Example embodiments provide a method, comprising: determining, by a first apparatus, that a communication process on a secondary communication channel, of a wireless communication system, between the first apparatus and a third apparatus terminates during a time window; wherein during the time window the first apparatus is configured to communicate with a second apparatus on a primary communication channel of the wireless communication system and to communicate with the third apparatus on the secondary communication channel; and instructing the third apparatus to switch to the primary communication channel before the end of the time window.

[0013] Example embodiments provide an apparatus, referred to as third apparatus, the third apparatus comprising at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the third apparatus at least to: receive from a first apparatus, an instruction to switch, before the end of a time window, to a primary communication channel of a wireless communication system to communicate with the first apparatus, wherein, during the time window, the third apparatus is configured to communicate with the first apparatus on a corresponding secondary communication channel of the wireless communication system and the first apparatus is configured to communicate with a second apparatus on the primary communication channel.

[0014] Example embodiments provide a method, comprising: receiving, by a third apparatus, from a first apparatus, an instruction to switch, before the end of a time window, to a primary communication channel of a wireless communication system to communicate with the first apparatus, wherein, during the time window, the third apparatus is configured to communicate with the first apparatus on a corresponding secondary communication channel of the wireless communication system and the first apparatus is configured to communicate with a second apparatus on the primary communication channel.Example embodiments provide an apparatus, referred to as first apparatus; the first apparatus comprising at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus at least to: send a frame to a third apparatus with instruction to switch to a primary communication channel of a wireless communication system after the end of a time window, according to a timer having a configuration indicated by a reception of the frame at the third apparatus; wherein during the time window the first apparatus is configured to communicate with a second apparatus on the primary communication channel and to communicate with the third apparatus on a secondary communication channel of the wireless communication system.

[0015] Example embodiments provide a method comprising sending, by a first apparatus, a frame to a third apparatus with instruction to switch to a primary communication channel of a wireless communication system after the end of the time window, according to a timer whose configuration is indicated by a reception of the frame at the third apparatus, wherein during the time window the first apparatus is configured to communicate with a second apparatus on the primary communication channel and to communicate with the third apparatus on a secondary communication channel of the wireless communication system.

[0016] Example embodiments provide an apparatus, referred to as third apparatus, the third apparatus comprising at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the third apparatus at least to: in response to determining that a timer has ended, switch, after the end of a time window, to a primary communication channel of a wireless communication system to communicate with a first apparatus, wherein during the time window the first apparatus is configured to communicate with a second apparatus on the primary communication channel and to communicate with the third apparatus on a secondary communication channel of the wireless communication system.

[0017] Example embodiments provide a method comprising in response to determining, by a third apparatus, that a timer has ended, switching, after the end of a time window, to a primary communication channel of a wireless communication system to communicate with a first apparatus, wherein during the time window the first apparatus is configured tocommunicate with a second apparatus on the primary communication channel and to communicate with the third apparatus on a secondary communication channel of the wireless communication system.

[0018] Example embodiments provide a non-transitory computer readable medium comprising program instructions that, when executed by an apparatus, cause the apparatus to perform at least any of the methods described herein.

[0019] A computer program product comprising processor executable instructions for causing an apparatus to perform any of the methods described herein.

[0020] “First,” “second,” “third,” etc. as used herein, are used as labels for nouns that they precede, and do not necessarily imply any type of ordering (e.g., spatial, temporal, logical) unless explicitly defined as such.

[0021] Brief Description of the Drawings

[0022] The accompanying figures are included to provide a further understanding of examples, and are incorporated in and constitute part of this specification. In the figures:

[0023] FIG.1 illustrates an example wireless communication system in which the present subject matter may be implemented in accordance with an example;

[0024] FIG. 2 is a flowchart of a method for using a primary communication channel of a wireless communication system in accordance with an example of the present subject matter;

[0025] FIG. 3 is a process block of a method for using a primary communication channel of a wireless communication system in accordance with an example of the present subject matter;

[0026] FIG. 4A is a diagram illustrating an example implementation of a notification frame according to an example of the present subject matter;

[0027] FIG. 4B is a diagram illustrating a reserved subfield of the notification frame according to an example of the present subject matterFIG. 4C is a diagram illustrating a reserved subfield of the notification frame according to an example of the present subject matter;

[0028] FIG. 5 is a diagram illustrating an example implementation of a response frame according to the present subject matter;

[0029] FIG. 6 is a diagram illustrating an example implementation of a response frame according to the present subject matter;

[0030] FIG. 7 is a flowchart of a method for early transition from a secondary to a primary communication channel of a wireless communication system in accordance with an example of the present subject matter;

[0031] FIG. 8 is a process block of a method for early transition from a secondary to a primary communication channel of a wireless communication system in accordance with an example of the present subject matter;

[0032] FIG. 9 is a diagram illustrating an example implementation of a data frame according to an example of the present subject matter;

[0033] FIG. 10 is a diagram illustrating an example implementation of a block acknowledgement frame according to an example of the present subject matter;

[0034] FIG. 11 is a flowchart of a method for time-based transition from a secondary to a primary communication channel of a wireless communication system in accordance with an example of the present subject matter;

[0035] FIG. 12 is a process block of a method for time-based transition from a secondary to a primary communication channel of a wireless communication system in accordance with an example of the present subject matter;

[0036] FIG. 13 is a block diagram showing an example of an apparatus according to an example of the present subject matter.Detailed Description

[0037] In the following description, for purposes of explanation and not limitation, specific details are set forth such as particular architectures, interfaces, techniques, etc., in order to provide a thorough understanding of the examples. However, it will be apparent to those skilled in the art that the disclosed subject matter may be practiced in other illustrative examples that depart from these specific details. In some instances, detailed descriptions of well-known devices and / or methods are omitted so as not to obscure the description with unnecessary detail.

[0038] A first apparatus may be provided. The first apparatus may be configured to access or use a primary communication channel of a wireless communication system. The primary communication channel may be used by the first apparatus and other apparatuses which may compete for access to the primary communication channel and is therefore referred to as the primary communication channel. As a result, these apparatuses, including the first apparatus, form a set of apparatuses contending for access to the primary communication channel.

[0039] The primary communication channel may occupy a bandwidth referred to as primary bandwidth, wherein each apparatus of the set of apparatuses has a bandwidth capability that is higher than or equal to the primary bandwidth. Accessing or using the primary communication channel by each given apparatus of the set of apparatuses may include contending by the given apparatus for access to the primary communication channel, and upon successfully gaining access, communicating by the given apparatus on the primary communication channel. Contending by the given apparatus may, for example, be performed through operations such as those in accordance with the Enhanced Distributed Channel Access (EDCA) mechanism, or, in some cases, through other contention-based or scheduled access mechanisms, such as OFDMA-based resource allocation. Communicating on the primary communication channel may comprise transmitting and / or receiving data on at least the primary communication channel. If the bandwidth capability of the given apparatus exceeds the primary bandwidth, the given apparatus may extend its communication beyond the primary bandwidth by aggregating one or more additional channels to the primary communication channel, provided that the total bandwidth usedremains within the bandwidth capability of the given apparatus and within the bandwidth capability of the apparatus with which it is communicating as the receiver of data. Hence, communication by the given apparatus on the primary communication channel may involve a respective frequency range, which may correspond to either the primary communication channel alone or an aggregated channel that includes the primary communication channel along with one or more additional channels. The aggregation may be performed dynamically based on channel availability. In one example implementation of the aggregation, to obtain an aggregated channel, the given apparatus may, upon successfully gaining access to the primary communication channel, evaluate the availability of additional adjacent channels, including those adjacent to the primary communication channel, within a broader bandwidth supported by the given apparatus. If available, the given apparatus may aggregate the primary communication channel with these one or more adjacent channels to form the aggregated channel. An available or free channel may be a channel that is not currently in use by any apparatus of the set of apparatuses other than the given apparatus. In one example implementation of the aggregation, if the given apparatus is not an access point, the given apparatus may perform the aggregation under control of the access point which may determine the set of additional channels available for aggregation e.g., enabling coordinated channel usage among multiple apparatuses to ensure efficient spectrum utilization, minimize contention, and reduce interference. For example, an 80 MHz apparatus may contend on a 20 MHz primary channel using EDCA, and if it wins access, it may check the other 20 MHz channels within the 80 MHz channel that includes the primary 20 MHz and create a channel out of those that are free.

[0040] The wireless communication system may comprise one or more wireless networks. A wireless network of the wireless communication system may refer to a network comprising one or more network nodes such as access points or the like which are capable of wireless radio communication with apparatuses connected to the wireless network. The set of apparatuses may belong to, or be connected to, a single wireless network within the wireless communication system, or they may belong to two or more neighboring wireless networks within the system, where the neighborhood may enable shared access to the same communication channel.Each apparatus of the set of apparatuses may be any device capable of connecting to and communicating within the wireless communication system. The apparatus may include a client device, such as smartphone, laptop, and Internet of Things (loT) device, or an access point (AP). In one example, each apparatus of the set of apparatuses may comprise a station (STA) and thus may be referred to as station. The apparatus which is not an access point may comprise a station and may thus be referred to as non-AP station. Hence, the station may refer to an access point or a non-AP station. The apparatus may, for example, be configured to operate in accordance with EDCA mechanism and integrating the present subject matter.

[0041] The first apparatus may be configured to set a time window. During the time window, the first apparatus may be configured to communicate with a second apparatus of the set of apparatuses on the primary communication channel. In one example, during the time window, the first apparatus may be configured to communicate with the second apparatus and one or more further second apparatuses of the set of apparatuses on the primary communication channel. These second apparatuses may collectively form a subset of second apparatuses within the set of apparatuses. Communicating on the primary communication channel during the time window with the subset of second apparatuses may comprise communicating with each second apparatus of the subset of second apparatuses on the primary communication channel alone or on an aggregated channel that may include the primary communication channel along with one or more additional available channels, provided that the overall bandwidth remains within the bandwidth capability of the each second apparatus and within the bandwidth capability of the first apparatus. Depending on the transmission technique, the frequency ranges involved in communication on the primary communication channel by the subset of second apparatuses during the time window may at least partially overlap (e.g., at the primary communication channel) or be dynamically allocated across separate bandwidth portions, ensuring a common access mechanism while allowing dynamic bandwidth utilization. During the time window the first apparatus may be configured to communicate with a third apparatus on a corresponding secondary communication channel of the wireless communication system. This third apparatus may be referred to as the specific third apparatus. In one example (referred to as multi-third apparatus communication example), during the time window, the first apparatus may be configured to communicate with the specific third apparatus and one or more further third apparatuses of the set ofapparatuses on their respective corresponding secondary communication channels. These third apparatuses may collectively form a subset of third apparatuses within the set of apparatuses.

[0042] The terms 'second apparatus' and 'third apparatus' may refer to distinct categories of apparatuses within the wireless communication system e.g., each assigned a specific role in communication operations. A 'second apparatus' may generally refer to an apparatus that communicates with the first apparatus on the primary communication channel, while a 'third apparatus' may refer to an apparatus that communicates with the first apparatus on a corresponding secondary communication channel. The term "during" may mean that communication may occur for at least part or the entire duration of the time window, but it does not necessarily imply continuous communication throughout the entire window. The secondary communication channel is referred to as 'secondary' because it may serve as an additional or alternative communication channel distinct from the primary communication channel, facilitating parallel or non-conflicting communication with other apparatuses. The secondary communication channel is referred to as 'corresponding' because it is assigned to the specific third apparatus, with which the first apparatus communicates during the time window. The secondary communication channel may refer to a specific frequency range that may be distinct from the frequency range of the primary communication channel. In the multi-third apparatus communication example, the corresponding secondary communication channels of the subset of third apparatuses may refer to specific frequency ranges, where these frequency ranges are distinct from each other and from the frequency range(s) involved in communication on the primary communication channel during the time window. Each secondary communication channel has bandwidth that is less than or equal to a bandwidth capability of the corresponding third apparatus. The frequency ranges of the secondary communication channels and frequency range(s) involved in communication on the primary communication channel during the time window, collectively may form at least part of a frequency band associated with the first apparatus.

[0043] The second apparatus and the specific third apparatus may be part of the set of apparatuses. The time window may enable the first apparatus and the second apparatus to access the primary communication channel, e.g., excluding other competing apparatuses, while still allowing the specific third apparatus to communicate on thecorresponding secondary communication channel. This may be advantageous because it may reduce contention on the primary communication channel and optimize overall spectrum utilization within the wireless communication system.

[0044] The present subject matter may provide example embodiments for managing access to the primary and secondary communication channels by the specific third apparatus or each third apparatus within the subset of third apparatuses. It is understood that one or more of the examples of the example embodiments may be combined as long as the combined examples are not mutually exclusive.

[0045] First example embodiment.

[0046] The present subject matter of the first example embodiment may enhance communication efficiency by enabling structured access to both primary and secondary communication channels. Specifically, notifying the third apparatus about its post-window communication channel may reduce the signaling overhead associated with repeated channel transitions. By allowing the first apparatus and the third apparatus to establish whether the third apparatus remains on the secondary communication channel beyond the designated period or switches back to the primary communication channel, the present subject matter may minimize unnecessary reconfigurations, optimize resource utilization, and improve overall network responsiveness.

[0047] According to one example of the first example embodiment, the first apparatus may be configured to notify the specific third apparatus to, after the time window has elapsed, further use the corresponding secondary communication channel for communication or switch to the primary communication channel for communication. This process may be referred to as notification operation. The phrase 'further use the corresponding secondary communication channel for communication' may imply that the specific third apparatus may continue transmitting and / or receiving with the first apparatus on the secondary communication channel beyond the time window. Using the secondary communication channel may comprise transmitting and / or receiving data on the secondary communication channel. The term 'switching' may refer to using the primary communication channel instead of the secondary communication channel for communication. The phrase 'for communication' in 'switch to the primary communicationchannel for communication' may imply that the specific third apparatus transitions to (or uses) the primary communication channel so that it may contend again for access to the primary communication channel to perform communication, e.g., with the first apparatus on the primary communication channel.

[0048] According to one example of the first example embodiment, in the multi-third apparatus communication example, each third apparatus of the subset of third apparatuses may, for example, be configured to operate as described herein with the specific third apparatus in accordance with the first example embodiment.

[0049] According to one example of the first example embodiment, notifying the specific third apparatus may comprise providing a notification to the specific third apparatus. In one example, the first apparatus may notify the specific third apparatus, by at least sending a notification to the specific third apparatus. The notification may, for example, indicate or represent an instruction to the specific third apparatus of whether the specific third apparatus, after the time window has elapsed, should continue using the corresponding secondary communication channel for communication or switch to the primary communication channel for communication. The notification may be sent through the primary communication channel, enabling an a priori procedure where the notification is provided in advance, e.g., while the specific third apparatus may still be contending and thus listening to the primary communication channel, such as at the beginning of the time window or right before it. Alternatively, the notification may be sent to the specific third apparatus through the corresponding secondary communication channel, enabling a dynamic decision where the notification may be made based on real-time conditions. This flexibility may be advantageous as it may allow for dynamic spectrum management and reduce congestion on the primary communication channel.

[0050] For example, the first apparatus may be configured to perform the notification based on a criterion. For instance, the first apparatus may be configured to request the specific third apparatus to remain on the secondary communication channel if it determines that there is sufficient low-latency (e.g., urgent) downlink traffic for the specific third apparatus to occupy at least two consecutive time windows.According to one example of the first example embodiment, the switching by the specific third apparatus to the primary communication channel may comprise using the primary communication channel, where such using includes contending for access to the primary communication channel, and upon successfully gaining access, the specific third apparatus transmitting and / or receiving data on the primary communication channel, wherein transmitting and / or receiving data on the primary communication channel may comprise transmitting and / or receiving data on at least the primary communication channel. For example, this may involve transmitting and / or receiving data on the primary communication channel and, if available, on one or more additional channels, provided that the total bandwidth used remains within the bandwidth capability of the specific third apparatus and within the bandwidth capability of the apparatus with which it is communicating as the receiver of data.

[0051] According to one example of the first example embodiment, the notification may be provided as a signaling element, such as a flag or an indicator or message, which may be embedded in an existing frame such as a control frame or included as part of a message such as a scheduling message. Alternatively, the notification may be provided as a dedicated frame, such as a management or control frame, or dedicated message which embeds the signaling element. The first approach may be advantageous in reducing signaling overhead and ensuring efficient use of existing frames, while the second approach may provide greater flexibility by explicitly conveying the notification in a separate frame. In any case, whether using an existing or dedicated frame or message, and whether the signaling element is embedded within a message or within a frame, the frame or message comprising the signaling element may be referred to as a notification frame. A 'frame' may represent a structured data unit used for signaling or data transmission between devices and addressing may ensure that the notification is explicitly directed to the intended recipient.

[0052] According to one example of the first example embodiment, in the multi-third apparatus communication example, each third apparatus of the subset of third apparatuses may be notified as described with reference to the specific third apparatus. The notification frame may contain multiple signaling elements, each associated with a respective third apparatus of the subset of third apparatuses and indicating the notification intended forthat third apparatus. This notification process in the context of the multi-third apparatus communication example, may also be referred to as the notification operation.

[0053] According to one example of the first example embodiment, the first apparatus may be configured to receive from the specific third apparatus a response acknowledging or rejecting the further use of the corresponding secondary communication channel or the switching to the primary communication channel after the time window has elapsed, and determine a scheduling of resources for the specific third apparatus for a period after the time window based on the received response. This submission of this response by the third apparatus may be referred to as response operation.

[0054] According to one example of the first example embodiment, the notification may either indicate that, after the time window has elapsed, the specific third apparatus should continue using the corresponding secondary communication channel or switch to the primary communication channel. In this context, 'acknowledging' may refer to the specific third apparatus confirming the notification, while 'rejecting' indicates that the specific third apparatus does not intend to follow the notification. If the notification specifies further use of the corresponding secondary communication channel, acknowledging may indicate that the specific third apparatus confirms its intention to continue using the corresponding secondary communication channel after the time window has elapsed, while rejecting may indicate that it does not intend to follow this instruction and thus switch to the primary communication channel. If the notification specifies switching to the primary communication channel, the specific third apparatus may have to acknowledge indicating that the specific third apparatus confirms its intention to switch.

[0055] According to one example of the first example embodiment, using the received response the first apparatus may determine a scheduling of resources for the specific third apparatus for the period following the time window. The period following the time window may begin at the end of the time window or after a predefined or dynamically determined interval e.g., depending on network conditions in the wireless communication system. This dynamic scheduling mechanism may be advantageous as it may optimize communication reliability by considering the specific third apparatus’s preferences or constraints.According to one example of the first example embodiment, the response may be received by the first apparatus through the same communication channel used for transmitting the notification or a different communication channel than the one used for transmitting the notification. The response may, for example, be sent by the specific third apparatus via the primary communication channel. This may, for example, be the case if the specific third apparatus was initially notified through the primary communication channel as part of an a priori procedure and has not yet started using the corresponding secondary communication channel. Alternatively, the response may be sent by the specific third apparatus via the corresponding secondary communication channel if the specific third apparatus is still using the corresponding secondary communication channel e.g., even if the notification was received on the primary communication channel.

[0056] According to one example of the first example embodiment, the scheduling of resources by the first apparatus may involve deciding which communication channel (primary or secondary communication channel) to assign to the specific third apparatus for the period following the time window, as well as determining specific time slots at which the specific third apparatus may transmit or receive data on the assigned communication channel. In one example, the first apparatus may follow the response as an explicit request and assign the communication channel accordingly. Alternatively, the first apparatus may treat the response as a preference and adjust the scheduling dynamically based on additional factors such as network conditions. The scheduling of resources by the first apparatus may further involve indicating other transmission parameters such as the bandwidth of transmissions and the modulation and coding scheme.

[0057] According to one example of the first example embodiment, the response may be provided as a signaling element, such as a flag or an indicator or message, which may be embedded in an existing frame such as a control frame or included as part of a message such as a scheduling message. Alternatively, the response may be provided as a dedicated frame, such as a management or control frame, or dedicated message which embeds the signaling element. In any case, whether using an existing or dedicated frame or message, and whether the signaling element is embedded within a message or within a frame, the frame or message comprising the signaling element of the response may be referred to as a response frame. The response frame may or may not be provided in the same format as the notification frame, with the same format offering advantages such asreduced signaling overhead and improved coordination efficiency. Conversely, using a different format for the response frame may enhance flexibility by allowing the specific third apparatus to reply based on its current communication conditions.

[0058] According to one example of the first example embodiment, the first apparatus may be configured to determine a scheduling of resources for the specific third apparatus for a period after the time window according to the notification. The notification may serve as an indication to the first apparatus regarding whether the specific third apparatus is expected to continue using the corresponding secondary communication channel or switch to the primary communication channel. Since the response from the specific third apparatus is not considered in this example, the scheduling decision may be made solely based on the notification. In one example, the notification itself may represent the scheduling decision. This approach may be advantageous as it may reduce the signaling overhead and latency associated with waiting for a response. Additionally, it may ensure a more deterministic scheduling process.

[0059] According to one example of the first example embodiment, the first apparatus may be configured to determine a first scheduling of resources for the specific third apparatus for a period after the time window according to the notification, receive from the specific third apparatus a response acknowledging or rejecting the further use of the corresponding secondary communication channel or the switching back to the primary communication channel after the time window has elapsed, and adjust the first scheduling of resources for the specific third apparatus for the period after the time window according to (or based on) the received response. This example may enable a hybrid approach combining proactive and reactive scheduling, allowing the first apparatus to determine an initial resource allocation based on the notification while still enabling dynamic adjustments based on the specific third apparatus’s response.

[0060] According to one example of the first example embodiment, the first apparatus may be configured to notify the specific third apparatus by at least sending a frame, addressed to the specific third apparatus. The frame in this example may comprise the notification frame.According to one example of the first example embodiment, the specific third apparatus may be configured to send to the first apparatus the response acknowledging or rejecting the further use of the corresponding secondary communication channel or switching to the primary communication channel.

[0061] According to one example of the first example embodiment, the specific third apparatus may be configured to send the response in a frame, wherein the frame comprising a header and body. The frame in this example may comprise the response frame.

[0062] According to some examples, the header of the response frame comprises a flag in a reserved subfield of the header, wherein the flag indicates the response. A reserved subfield may be a predefined portion of the frame that is allocated for future use, protocol extensions, or specific control information without affecting existing functionalities.

[0063] The present subject matter of the first example embodiment may provide the notification frame using alternative advantageous techniques. One example implementation may be to include a single-bit field in the notification frame, where one value indicates continued use of the secondary communication channel and the other indicates switching to the primary communication channel. Alternatively, a multi-bit field in the notification frame may be provide more flexibility by encoding additional options, such as adaptive switching based on network conditions. Alternatively, without considering specific field contents, the nature of the notification frame or its format may indicate or instruct the continued use of the secondary communication channel, while another format may indicate or instruct a transition to the primary communication channel.

[0064] The present subject matter of the first example embodiment may provide the response frame using alternative advantageous techniques. One example implementation may be to include a single-bit field in the response frame, where one value indicates the rejection of the notification and the other indicates the acknowledgement of the notification. Alternatively, a multi-bit field in the response frame may be provide more flexibility by encoding additional options. Alternatively, without considering specific field contents, the nature of the response frame or its format may indicate the rejection of the notification, while another format may indicate the acknowledgement of the notification.According to one example of the first example embodiment, the specific third apparatus may be configured to switch to the primary communication channel or further use the secondary communication channel depending on the response. For example, if the response acknowledges the notification, the specific third apparatus may apply the instruction indicated in the notification. Alternatively, if the response rejects the notification, the specific third apparatus may deviate from the indicated instruction. For instance, if the notification indicates further use of the corresponding secondary communication channel and the response rejects it, the specific third apparatus may attempt to switch to the primary communication channel instead. This may be advantageous if the first apparatus follows a response-based scheduling approach, allowing for adaptive resource allocation based on the specific third apparatus’s preferences. Alternatively, if the response is not sent by the specific third apparatus, the specific third apparatus may be configured to switch to the primary communication channel or further use the secondary communication channel according to the notification. For example, if the notification indicates further use of the corresponding secondary communication channel, the specific third apparatus may continue usage of the corresponding secondary channel after the time window has elapsed. Conversely, if the notification indicates switching to the primary communication channel, the specific third apparatus may transition to the primary communication channel after the time window has elapsed. This may ensure that communication proceeds even in the absence of a response. This approach may enhance flexibility by accommodating both response-driven and predefined scheduling mechanisms.

[0065] According to one example of the first example embodiment, the notification frame comprises a body and header. The body comprises a first field and a second field, with the first field being applicable for all addressed apparatuses in the notification frame, and the second field being applicable per addressed apparatus in the notification frame. The first apparatus may be configured to perform at least one of the following: insert in the first field a flag indicating the notification, wherein the flag specifies whether the notification applies to a plurality of third apparatuses to further use the corresponding secondary communication channels or for the plurality of third apparatuses to switch to the primary communication channel after the time window has elapsed, the plurality of third apparatuses comprising the specific third apparatus; or insert in the second field an individual flag for a third apparatus of the plurality of the third apparatuses, the individualflag indicating whether the respective third apparatus is to further use the corresponding secondary communication channel or to switch to the primary communication channel after the time window has elapsed.

[0066] According to one example of the first example embodiment, the first field applies to all addressed apparatuses in the notification frame, allowing fora collective indication, while the second field is specific to individual addressed apparatuses, enabling device-specific instructions. The first apparatus may perform at least one of two operations: 1) it may insert a flag in the first field to provide a general notification applicable to the plurality of third apparatuses, indicating whether they should continue using the corresponding secondary communication channels or switch to the primary communication channel after the time window has elapsed and 2) it may insert an individual flag in the second field, assigning a separate notification to each third apparatus, specifying whether that particular third apparatus should continue using the secondary communication channel or transition to the primary communication channel. This approach may reduce signaling overhead when a uniform instruction is sufficient for all addressed apparatuses, while still allowing fine-grained control when individual scheduling decisions are necessary.

[0067] According to one example of the first example embodiment, in the multi-third apparatus communication example, the plurality of the third apparatuses may be the subset of third apparatuses. Each third apparatus of the subset of third apparatuses is associated with a corresponding secondary communication channel. During the time window, the first apparatus may be configured to communicate with each third apparatus of the subset of third apparatuses on the corresponding secondary communication channel.

[0068] According to one example of the first example embodiment, the first apparatus may be configured to perform the setting of the time window by at least sending a message addressed to an apparatus other than the first apparatus, wherein the message indicates the time window. For example, the message may be sent by the first apparatus to the set of apparatuses excluding the first apparatus. For example, the message may be sent by the first apparatus to the second apparatus and the specific third apparatus. The message may, for example, be sent via the primary communication channel. The message may serve as a signaling mechanism to inform the receiving apparatus about when it is permitted to transmit or receive data, ensuring efficient coordination of network resources.For example, the first apparatus may be configured to set the time window so that the first apparatus may be configured to communicate with the second apparatus on the primary communication channel during the time window. The setting of the time window may comprise an operation referred to as time window setting-related operation. The time window setting-related operation may, for example, be performed as follows. Once the first apparatus has gained access to the primary communication channel through contention, it may select the second apparatus (or additional second apparatuses from the set of apparatuses) to participate in communication on the primary communication channel during the time window. To reserve the primary communication channel, the first apparatus may broadcast its intent to communicate. The second apparatus may then respond, confirming its availability and readiness for transmission. Once the first apparatus receives the confirmation response, the time window may be reserved, and other apparatuses, such as a specific third apparatus, may defer access to (contending to) the primary communication channel until at least the end of the time window.

[0069] According to one example of the first example embodiment, the first apparatus may be configured to: perform the setting of the time window and the notification of the specific third apparatus by at least sending a same message indicating the time window and providing the notification to the specific third apparatus. The message may, for example, be sent via the primary communication channel. This may enable a seamless integration of the present subject matter with existing signaling and may reduce congestion.

[0070] According to one example of the first example embodiment, the first apparatus may be configured to allocate to the specific third apparatus the corresponding secondary communication channel. The allocation may further indicate the time window during which the specific third apparatus may be configured to communicate with the first apparatus on the corresponding secondary communication channel. In the multi-third apparatus communication example, the first apparatus may be configured to allocate to each third apparatus of the subset of third apparatuses the corresponding secondary communication channel. This process either performed for one third apparatus or for the subset of third apparatuses may be referred to as allocation operation.According to one example of the first example embodiment, in order to perform the allocation operation, the first apparatus may be configured to gather information from the set of apparatuses, wherein the information provided by each apparatus may include supported communication channels by the apparatus, the time required by the apparatus for channel switching, bandwidth capability of the apparatus, and other details which may be used for performing the allocation operation. This process may be referred to as an initialization operation.

[0071] According to one example of the first example embodiment, the allocation operation may or may not comprise the initialization operation. In one example, the allocation operation may comprise the notification operation. In one example, the allocation operation may comprise the notification operation and the response operation.

[0072] According to one example of the first example embodiment, the allocation operation may form an operation which may be referred to as secondary communication channel coordination operation. Alternatively, the allocation operation and the notification operation may collectively form the secondary communication channel coordination operation. Alternatively, the allocation operation, the notification operation and the response operation may collectively form the secondary communication channel coordination operation. The allocation operation, the notification operation and the response operation may thus be individual operations of the secondary communication channel coordination operation. The initialization operation may provide parameters, configurations, or conditions that may be used for the execution of the secondary communication channel coordination operation.

[0073] The present subject matter of the first example embodiment may enable a time-optimized execution or integration of the secondary communication channel coordination operation and the time window setting-related operation, ensuring that both the communication between the first apparatus and the specific third apparatus, as well as the communication between the first apparatus and the second apparatus, occur within the time window. This may be achieved, for example, by integrating these operations into a unified framework that may ensure efficient resource allocation and seamless channel transitions within the time window. For example, frames or messages exchanged or used in the time window setting-related operation may also serve to perform one or more individual operations ofthe secondary communication channel coordination operation. This reuse of signaling may minimize latency and streamline coordination.

[0074] According to one example of the first example embodiment, the wireless communication system may be a Wi-Fi system, but the disclosure is not limited to Wi-Fi alone. The wireless communication system may also be adapted for use in other wireless communication systems, such as cellular networks, and any other wireless protocols that involve managing access to a shared communication channel. The Wi-Fi system may, for example, operate in accordance with an IEEE 802.11 standard such as, for example, 802.11n, 802.11ac, 802.11ax, 802.11be, or802.11bn.

[0075] According to one example of the first example embodiment, the time window comprises a transmission opportunity (TXOP) interval. For example, the time window is the TXOP interval. Defining the time window as a TXOP interval may seamlessly integrate with existing medium access control mechanisms, wherein the setting of the time window may be performed at least according to an existing channel access procedure, such as EDCA.

[0076] According to one example of the first example embodiment, the notification frame may comprise a multi-user request to send (MU-RTS) frame or a buffer status report poll (BSRP) frame. The first field may, for example, comprise the common info field and the second field may, for example, comprise the user info list field. The single flag may for example be set in a reserved sub-field of the common info field of the notification frame. According to some examples, the reserved sub-field may be any one of: B4 (bit 4) through B15 subfields and B20 through B63 subfields. In the multi-third apparatus communication example, each individual flag may be inserted into a reserved sub-sub-field of a sub-field of the user info list field assigned to the respective third apparatus of the subset of third apparatuses, and the reserved sub-sub-field may be any of the B20 through B39 subfields.

[0077] According to one example of the first example embodiment, the response frame may comprise a QoS Null Data frame orclear-to-send (CTS) frame, and the reserved sub-filed of the header of the response frame is any one of: B8 through B15 subfields in case of the CTS frame; otherwise the reserved sub-filed is any one of: B10 subfield, B11 subfield, B14 subfield or B15 subfield in case of the QoS Null Data frame.Using specific bit positions within reserved sub-fields may optimize frame space utilization by efficiently embedding control information without increasing frame size, minimize signaling overhead because it may eliminate the need for additional dedicated signaling frames, and maintain compatibility with existing protocol structures because it may leverage predefined fields without altering the fundamental frame format or disrupting legacy device operations.

[0078] According to one example of the first example embodiment, the first apparatus comprises an access point and remaining apparatuses of the set of apparatuses comprise non-AP STAs.

[0079] According to one example of the first example embodiment, the set of apparatuses are part of a basic service set (BSS) of the wireless communication system, wherein the first apparatus comprises an access point and remaining apparatuses of the set of apparatuses comprise non-AP STAs. The specific third apparatus may comprise a non-AP STA and the second apparatus may comprise a non-AP STA. The BSS may be an example implementation of the wireless network. In the multi-third apparatus communication example, each third apparatus of the subset of third apparatuses may be a non-AP STA.

[0080] According to one example of the first example embodiment, the notification frame may comprise a MU-RTS frame and the response frame may comprise a CTS frame. In one example, this pair of frames MU-RTS and CTS may further be used for the allocation operation. According to some examples, the notification frame may comprise a BSRP frame and the response frame may comprise a Buffer Status Report (BSR) frame. In one example, this pair of frames BSRP and BSR may further be used for the allocation operation. Hence, these examples may provide an example implementation of the integration of the secondary communication channel coordination operation and the time window setting-related operation, because the pairs of frames MU-RTS / CTS and BSRP / BSR, which may be used for the setting of the TXOP according to a WiFi system, may be adapted or updated in order to enable the notification operation, the response operation as well as the allocation operation.According to one example of the first example embodiment, the secondary communication channel coordination operation may be included in Dynamic Sub-band Operation (DSO), which may be referred to as DSO operation. The term sub-band may refer to a communication channel e.g., a secondary communication channel. The DSO operation may, for example, comprise the allocation operation. The initialization operation may provide parameters, configurations, or conditions that may be used for the execution of the DSO operation. The DSO operation may, for example, be enabled by exchanging between the first apparatus and the specific third apparatus an initial control frame (ICF) which may be referred to as DSO ICF and a Response Control Frame (RCF) which may be referred to as DSO RCF. In the multi-third apparatus communication example, the DSO operation may be enabled by using an ICF collectively for the subset of third apparatuses, while multiple RCFs may be provided by the subset of third apparatuses respectively. In case the time window is a TXOP, the TXOP may be referred to as DSO TXOP. The flag inserted in the notification frame or response frame may be referred to as extended DSO flag.

[0081] The present subject matter of the first example embodiment may improve the DSO operation by adapting the DSO operation. The DSO operation may be adapted by including the notification operation in the DSO operation and optionally additionally the response operation.

[0082] According to one example of the first example embodiment, the first apparatus may comprise an AP and the specific third apparatus (or each third apparatus) may comprise a non-AP STA. In this context the specific third apparatus may be referred to as DSO non-AP STA. The present subject matter may provide a mechanism to enable the AP and non-AP STA to negotiate whether non-AP STA remains on the corresponding secondary communication channel (which may be referred to as DSO location or DSO sub-band) after DSO TXOP. For that, a new field in the DSO ICF may indicate whether the AP wants the non-AP STA to remain in its DSO location after the current DSO TXOP. DSO ICF may either be a newly defined trigger frame or DSO-adapted pre-existing trigger frames such as MU-RTS, BSRP, Basic Trigger etc. Additionally, a new field in the DSO RCF may indicate whether the non-AP STA intends to remain in its DSO location after the current DSO TXOP. The DSO RCF may either be a newly defined control frame or a DSO-adapted pre-existing frame such as CTS, BSR, etc. The DSO ICF may provide anexample implementation of the notification frame. The DSO RCF may provide an example implementation of the response frame. Hence, the DSO ICF may either be a newly defined frame specific to DSO operation or DSO-adapted versions of pre-existing frames, such as MU-RTS, BSRP, or Basic Trigger. These DSO “adaptations” may include elements like an intermediate frame check sequence (FCS), which may allow the addressed non-AP STAs to decode the trigger frame early (e.g., mid-frame) and padding, which may afford non-AP STAs assigned to DSO locations a little extra time to move to their DSO locations. This padding may still not be long enough to allow all non-AP STAs assigned to DSO locations time to get there before the trigger frame completes. The extended DSO flag may be implemented as either one flag for all addressed non-AP STAs, in which case the value holds for all, or one individual flag per addressed non-AP STA. For example, if the AP initiates a DSO TXOP using a DSO-adapted MU-RTS or BSRP, it may include one flag that indicates the AP’s extended DSO preference for all addressed non-AP STAs or one flag per addressed non-AP STA, which indicates the AP’s preference for each. Enabling the AP to negotiate with its non-AP STAs whether they remain on their DSO locations may be useful in terms of the AP’s scheduling. For example, if the AP knows that a non-AP STA plans to return to its primary location after the DSO TXOP, and that the non-AP STA requires N ps to return to that primary location, it may plan to end the non-AP STA’s DL transmissions at least N ps before the end of the DSO TXOP to give the non-AP STA a chance to return to the primary communication channel before it is released for contention.

[0083] The present subject matter of the first example embodiment, may thus maximize the use of the AP’s bandwidth (BW). The present subject matter may reduce the overhead that may be required every time the AP requests its non-AP STAs move to DSO locations. Indeed, giving the AP and non-AP STA the ability to request / agree to the non-AP STA remaining in its DSO location beyond the current TXOP could significantly reduce this overhead.

[0084] Second example embodiment.

[0085] The present subject matter of the second example embodiment may provide a mechanism for a device to transition back to the primary communication channel before a designated period ends, ensuring it is ready to access the primary communicationchannel as soon as it becomes available. For example, if the device no longer has data to transmit or receive, or if it prefers to prioritize timely access to the primary communication channel over utilizing the remaining communication opportunities in the designated period, the present subject matter may facilitate coordination of this early return between the devices, optimizing channel utilization and reducing contention delays.

[0086] According to one example of the second example embodiment, the first apparatus may be configured to determine that a communication process on the secondary communication channel between the first apparatus and the specific third apparatus terminates during the time window. The first apparatus may be configured to determine that, during the time window, the communication process on the secondary communication channel between the first apparatus and the specific third apparatus terminates. For example, the first apparatus may be configured to determine whether, during the time window, the communication process on the secondary communication channel between the first apparatus and the specific third apparatus terminates.

[0087] According to one example of the second example embodiment, the communication process may refer to a structured exchange of data between two or more apparatuses in accordance with an application or a predefined communication protocol. The communication process may involve one or more various types of data, including control messages, application-specific data, and real-time or non-real-time traffic. The characteristics of the communication process may include data priority, latency requirements, and reliability constraints. For example, a low-latency communication process may represent applications such as voice over IP (VoIP), online gaming, or industrial automation. Conversely, a non-time-sensitive communication process may represent applications such as file transfers or background data synchronization. The communication processes may differ from one communication channel to another. For example, after switching to the primary communication channel, the specific third apparatus may be configured to exchange data with the first apparatus according to a different communication process, which may have distinct parameters, requirements, or transmission characteristics compared to the communication process on the corresponding secondary communication channel.According to one example of the second example embodiment, in response to determining that the communication process on the secondary communication channel between the first apparatus and the specific third apparatus terminates during the time window, the first apparatus may be configured to instruct the specific third apparatus to switch to the primary communication channel before the end of the time window. The termination of the communication process occurs during the time window.

[0088] According to one example of the second example embodiment, in the multi-third apparatus communication example, each third apparatus of the subset of third apparatuses may, for example, be configured to operate as described herein with the specific third apparatus in accordance with the second example embodiment.

[0089] According to one example of the second example embodiment, the switching by the specific third apparatus to the primary communication channel may comprise using the primary communication channel, where such using includes contending for access to the primary communication channel, and upon successfully gaining access, the specific third apparatus transmitting and / or receiving data on the primary communication channel, wherein transmitting and / or receiving data on the primary communication channel may comprise transmitting and / or receiving data on at least the primary communication channel. For example, this may involve transmitting and / or receiving data on the primary communication channel and, if available, on one or more additional channels, provided that the total bandwidth used remains within the bandwidth capability of the specific third apparatus and within the bandwidth capability of the apparatus with which it is communicating as the receiver of data.

[0090] According to one example of the second example embodiment, instructing the specific third apparatus may comprise providing an instruction to the specific third apparatus. In one example, the first apparatus may instruct the specific third apparatus, by at least sending an instruction to the specific third apparatus. The instruction may request the specific third apparatus to, before the end of the time window, switch from the corresponding secondary channel to the primary communication channel. The instruction may, for example, be sent to the specific third apparatus through the corresponding secondary communication channel. The instruction may be referred to as switching instruction.According to one example of the second example embodiment, the instruction may be provided as a signaling element, such as a flag or an indicator or message, which may be embedded in an existing frame such as a control frame or included as part of a message such as a scheduling message. Alternatively, the instruction may be provided as a dedicated frame, such as a management or control frame, or dedicated message which embeds the signaling element. The first approach may be advantageous in reducing signaling overhead and ensuring efficient use of existing frames, while the second approach may be advantageous in providing greater flexibility by explicitly conveying the instruction in a separate frame.

[0091] According to one example of the second example embodiment, in the multi-third apparatus communication example, the communication during the time window between each third apparatus of the subset of the third apparatuses with the first apparatus on the corresponding secondary communication channel may be performed in accordance with its respective communication process. The first apparatus may be configured to instruct each third apparatus of at least part of the subset of third apparatuses to switch to the corresponding primary communication channel before the end of the time window, in response to determining the communication process on the secondary communication channel of the each third apparatus terminates during the time window. For example, each third apparatus of the at least part of the subset of third apparatuses may be instructed as described with reference to the specific third apparatus. The at least part of the subset of the third apparatuses may be the third apparatuses for which the first apparatus determined that the corresponding communication process terminates during the time window while the remaining third apparatuses are those for which it was not determined that their corresponding communication process terminates during the time window.

[0092] According to one example of the second example embodiment, the first apparatus may be configured to: instruct the specific third apparatus through a first data frame or a first acknowledgment frame associated with the communication process and transmitted by the first apparatus to the specific third apparatus. For example, the first apparatus may be configured to send the first data frame associated with the communication process to the specific third apparatus. The first data frame may be indicative of the instruction toswitch by the specific third apparatus from the corresponding secondary communication channel to the primary communication channel before the end of the time window. Alternatively, the first apparatus may be configured to send the first acknowledgment frame associated with the communication process to the specific third apparatus. The first acknowledgment frame may be indicative of the instruction to switch by the specific third apparatus from the corresponding secondary communication channel to the primary communication channel before the end of the time window. The terms 'First' and 'Second' preceding frames are used as labels for distinction and do not imply any specific ordering or sequence. This example may enable efficient signaling by allowing the first apparatus to convey instructions within existing data or acknowledgment frames, reducing additional signaling overhead and ensuring seamless coordination with the specific third apparatus.

[0093] According to one example of the second example embodiment, the first apparatus may be configured to: to insert a flag in a subfield of a header of the first data frame indicating the switching instruction to the primary communication channel. Alternatively, the first apparatus may be configured to: to insert a flag in a subfield of a header of the first acknowledgment frame indicating the switching instruction to the primary communication channel. The first data frame may, for example, be the last data frame associated with the communication process that is transmitted on the corresponding secondary communication channel, after which: no further data remains to be sent or no additional data is scheduled for transmission, and the specific third apparatus may switch to the primary communication channel. The first acknowledgment frame may, for example, be the last acknowledgment frame associated with the communication process that is transmitted on the corresponding secondary communication channel, after which: no further data remains to be sent or no additional data is scheduled for transmission, and the specific third apparatus may switch to the primary communication channel. Inserting a flag in a subfield of the header of a data or acknowledgment frame may enable compact and efficient signaling, reducing additional transmission overhead while ensuring timely and seamless coordination for the specific third apparatus to switch to the primary communication channel.

[0094] According to one example of the second example embodiment (referred to as first determination example), the first apparatus may be configured to: perform the determining that the communication process terminates during the time window by atleast determining that: no data associated with the communication process remains to be transmitted by the first apparatus to the specific third apparatus, and / or no data remains to be received by the first apparatus from the specific third apparatus in accordance with the communication process. For example, the first apparatus may be configured to determine that, during the time window, the communication process terminates by determining that no data associated with the communication process remains to be transmitted by the first apparatus to the third apparatus, and / or determining that no data remains to be received by the first apparatus from the third apparatus in accordance with the communication process. This example may ensure efficient resource management by allowing the first apparatus to dynamically identify communication termination, minimizing unnecessary channel occupancy.

[0095] According to one example of the second example embodiment (referred to as second determination example), the first apparatus may be configured to perform the determining that the communication process terminates during the time window by at least one of the following: receiving from the specific third apparatus a request to terminate the communication process; or receiving from the specific third apparatus a second data frame indicating a termination of the communication process during the time window; or receiving from the specific third apparatus a second acknowledgement frame indicating a termination of the communication process during the time window. For example, the first apparatus may be configured to determine that, during the time window, the communication process terminates by receiving from the specific third apparatus a request to terminate the communication process or receiving from the specific third apparatus a second data frame indicating a termination of the communication process during the time window or receiving from the specific third apparatus a second acknowledgement frame indicating a termination of the communication process during the time window. This example may enhance communication efficiency by enabling the first apparatus to promptly detect the termination of the communication process based on explicit signaling from the specific third apparatus, reducing unnecessary resource allocation.

[0096] According to one example of the second example embodiment (referred to as third determination example), the first apparatus may be configured to perform the determining that the communication process terminates during the time window by at leastdetermining that the communication process does not involve low latency data following a termination time of the communication process. For example, the first apparatus may be configured to determine that, during the time window, the communication process terminates by at least determining that the communication process does not involve low latency data following a termination time of the communication process. This example may optimize resource allocation by ensuring that channel transitions are managed efficiently for prioritizing low-latency data transmissions and preventing unnecessary delays for time-sensitive communication.

[0097] According to one example of the second example embodiment, the first apparatus may be configured to: perform the determining that the communication process terminates during the time window by at least: informing the specific third apparatus of a termination of the communication process during the time window and receiving a response from the specific third apparatus confirming the termination. For example, the first apparatus may be configured to perform any one of the first, second and third determination examples, and additionally: inform the specific third apparatus of a termination of the communication process during the time window and receive a response from the specific third apparatus confirming the termination. Alternatively, the first apparatus may rely solely on this exchange, informing the third apparatus and receiving confirmation, as the sole method of determining that the communication process has ended during the time window. This example may ensure clear coordination between the apparatuses, reducing ambiguity about communication status.

[0098] According to one example of the second example embodiment, the informing of the specific third apparatus and the receiving of the response are performed during an association of the specific third apparatus with the wireless communication system. This process may be part of an initialization operation. Performing the informing of the specific third apparatus and receiving the response during the association of the specific third apparatus with the wireless communication system may ensure that communication termination procedures are established early, enabling seamless transitions.

[0099] According to one example of the second example embodiment, the first apparatus may be configured to: receive a flag in a subfield of a header of the second data frame indicating a termination of the communication process during the time window; or receivea flag in a subfield of a header of the acknowledgement frame indicating a termination of the communication process during the time window.

[0100] According to one example of the second example embodiment, the communication process terminates in response to at least one of the following: completion of the communication process, interruption of the communication process, or a determination that communication in accordance with the communication process is not required.

[0101] According to one example of the second example embodiment, the specific third apparatus may be configured to receive the instruction in a first data frame comprising a flag in a subfield of a header of the first data frame indicating the switch to the primary communication channel. According to one example, the specific third apparatus may be configured to receive the instruction in a first acknowledgement frame comprising a flag in a subfield of a header of the first acknowledgement frame indicating the switch to the primary communication channel.

[0102] According to one example of the second example embodiment, the specific third apparatus may be configured to: receive the instruction in response to sending to the first apparatus a second data frame indicating a termination of the communication process during the time window; or receive the instruction in response to sending to the first apparatus a second acknowledgement frame indicating a termination of the communication process during the time window.

[0103] According to one example of the second example embodiment, the specific third apparatus may be configured to: send a flag in a subfield of a header of the second data frame indicating a termination of the communication process during the time window, or send a flag in a subfield of a header of the second acknowledgement frame indicating a termination of the communication process during the time window.

[0104] According to one example of the second example embodiment, the first apparatus may be configured to set the time window according to the time window setting-related operation.According to one example of the second example embodiment, the first apparatus may be configured to allocate to the specific third apparatus the corresponding secondary communication channel. The allocation may further indicate the time window during which the specific third apparatus may be configured to communicate with the first apparatus on the corresponding secondary communication channel. In the multi-third apparatus communication example, the first apparatus may be configured to allocate to each third apparatus of the subset of third apparatuses the corresponding secondary communication channel. This process either performed for one third apparatus or for the subset of third apparatuses may be referred to as allocation operation.

[0105] According to one example of the second example embodiment, in order to perform the allocation operation, the first apparatus may be configured to gather information from the set of apparatuses, wherein the information provided by each apparatus may include supported communication channels by the apparatus, the time required by the apparatus for channel switching, bandwidth capability of the apparatus, and other details which may be used for performing the allocation operation. This process may be part of the initialization operation. The allocation operation may or may not comprise the initialization operation. The initialization operation may provide parameters, configurations, or conditions that may be used the execution of the allocation operation.

[0106] According to one example of the second example embodiment, the setting of the time window comprises allocating to the specific third apparatus the corresponding secondary communication channel. For example, the setting of the time window may comprise the allocation operation.

[0107] According to one example of the second example embodiment, the wireless communication system may be a Wi-Fi system, but the disclosure is not limited to Wi-Fi alone. The wireless communication system may also be adapted for use in other wireless communication systems, such as cellular networks, and any other wireless protocols that involve managing access to a shared communication channel. The Wi-Fi system may, for example, operate in accordance with an IEEE 802.11 standard such as, for example, 802.11n, 802.11ac, 802.11ax, 802.11be, or802.11bn.According to one example of the second example embodiment, the time window comprises a TXOP interval. Defining the time window as a TXOP interval may seamlessly integrate with existing medium access control mechanisms, wherein the setting of the time window may be performed at least according to an existing channel access procedure, such as EDCA.

[0108] According to one example of the second example embodiment, the first apparatus comprisesan access point and remaining apparatuses of the set of apparatuses comprise non-AP STAs.

[0109] According to one example of the second example embodiment, the set of apparatuses are part of a BSS of the wireless communication system, wherein the first apparatus comprisesan access point and remaining apparatuses of the set of apparatuses comprise non-AP STAs. The specific third apparatus may comprise a non-AP STA and the second apparatus may comprise a non-AP STA. The BSS may be an example implementation of the wireless network. In the multi-third apparatus communication example, each third apparatus of the subset of third apparatuses may be a non-AP STA.

[0110] According to one example of the second example embodiment, the allocation operation may comprise DSO, which may be referred to as DSO operation. The term sub-band may refer to a communication channel e.g., a secondary communication channel. The DSO operation may, for example, comprise the allocation operation. The initialization operation may provide parameters, configurations, or conditions that may be used for the execution of the DSO operation. The DSO operation may, for example, be enabled by exchanging between the first apparatus and the specific third apparatus an ICF which may be referred to as DSO ICF and a RCF which may be referred to as DSO RCF. In the multi-third apparatus communication example, the DSO operation may be enabled by using an ICF collectively for the subset of third apparatuses, while multiple RCFs may be provided by the subset of third apparatuses respectively. In case the time window is a TXOP, the TXOP may be referred to as DSO TXOP. The flag inserted in the first data frame, second data frame, first acknowledgement frame, or second acknowledgement frame may be referred to as end DSO flag.The present subject matter of the second example embodiment may improve the DSO operation by adapting the DSO operation. The adaptation of the DSO operation may be performed by, for example, adapting the initialization operation of the DSO operation. The initialization operation may further include the informing of the specific third apparatus of a termination of the communication process during the time window and the receiving of a response from the specific third apparatus confirming the termination.

[0111] According to one example of the second example embodiment, the first apparatus may comprise an AP and the specific third apparatus (or each third apparatus) may comprise a non-AP STA. In this context, the specific third apparatus may be referred to as DSO non-AP STA. The present subject matter may provide a mechanism to enable AP and non-AP STA to trigger early return (e.g., before end of TXOP) of non-AP STA to the primary communication channel from the corresponding secondary communication channel (which may be referred to as DSO location or DSO sub-band). For that, a new field in the data frame that allows the AP or the non-AP STA to indicate it will not send any more data frames in the current TXOP may be provided. And a new field in the (block-) acknowledgement frame that allows the AP or the non-AP STA to indicate it will not receive any more data frames in the current TXOP may be provided. These features may allow the AP to “release” the non-AP STA from the DSO location earlier than the end of the TXOP, so that the non-AP STA is ready to contend for the primary communication channel when it becomes free. This may particularly be useful when the AP no longer has downlink (DL) traffic to send the non-AP STA. Similarly, these features may let the non-AP STA indicate to the AP that it plans to return to the primary communication channel earlier than the end of the TXOP, and therefore not to send it any more data or schedule any more uplink (UL) transmission opportunities.

[0112] According to one example of the second example embodiment, a flag may be defined. The flag may be inserted into the headers of data and acknowledgement frames and enable the AP and non-AP STA to indicate an end to their DSO communication for the time being. This flag may be referred to as an end DSO flag. The flag may be a permanent flag that is set to 0 or 1 depending on whether the sender wants to end or continue DSO, or it can be a flag that is only inserted when the AP or non-AP STA wants to end DSO. In either case, when an AP sends this flag = 1 , it indicates that the AP will no longer transmit data to the non-AP STA or trigger UL transmission opportunities for the non-AP STA.This releases the non-AP STA to return to the primary communication channel as soon as the current frame exchange sequence completes. Similarly, if the non-AP STA transmits this flag =1 in a data or block acknowledgment (BA) frame to the AP, it indicates to the AP that the non-AP STA will be returning to the primary communication channel as soon as the current frame exchange sequence completes. This capability may allow the AP to signal to its non-AP STA to return early to the primary communication channel if it no longer has data to send the non-AP STA. The AP and non-AP STA may also preagree (during DSO setup e.g., during the initialization operation) that the AP will “release” the non-AP STA early from the DSO TXOP whenever possible (e.g., if it doesn’t have urgent low latency downlink traffic for the non-AP STA). It may also enable the non-AP STA to signal to the AP that the non-AP STA intends to return to the primary communication channel as soon as the current frame exchange sequence completes. The non-AP STA may do this if it gets urgent low latency uplink traffic and want to contend for the primary communication channel the moment it is free.

[0113] Third example embodiment.

[0114] The present subject matter of the third example embodiment may enable precise and automated channel transitions, reducing signaling overhead and ensuring synchronized coordination between devices. Specifically, the present subject matter may allow the first apparatus and the third apparatus to establish an agreement on when the third apparatus should return to its primary communication channel e.g., if a current communication channel cannot be reserved in the next contention period. By predefining the waiting duration before transitioning back, the present subject matter may ensure efficient use of available communication resources, prevent unnecessary delays, and avoid transmission conflicts.

[0115] According to one example of the third example embodiment, the first apparatus may be configured to send a frame to the specific third apparatus with instruction to switch to the primary communication channel after the end of the time window, according to a timer having a configuration indicated by a reception of the frame at the specific third apparatus. For example, the first apparatus may be configured to send a frame to the specific third apparatus, providing an instruction to switch from the corresponding secondary communication channel to the primary communication channel after the time window hasended. The switching process may be performed using the timer, which is configured based on information contained in the received frame and / or derived from the reception of the frame. Upon receiving the frame, the specific third apparatus may determine the timer configuration and execute the switching operation accordingly, ensuring a controlled and timely transition between communication channels.

[0116] According to one example of the third example embodiment, in the multi-third apparatus communication example, each third apparatus of the subset of third apparatuses may, for example, be configured to operate as described herein with the specific third apparatus in accordance with the third example embodiment. For example, in the multi-third apparatus communication example, the first apparatus may be configured to send a frame to each third apparatus of at least part of the subset of third apparatuses with instruction to switch to the primary communication channel after the end of the time window, according to a respective timer whose configuration is indicated by a reception of the frame at the each third apparatus.

[0117] According to one example of the third example embodiment, the switching by the specific third apparatus to the primary communication channel may comprise using the primary communication channel, where such using includes contending for access to the primary communication channel, and upon successfully gaining access, the specific third apparatus transmitting and / or receiving data on the primary communication channel, wherein transmitting and / or receiving data on the primary communication channel may comprise transmitting and / or receiving data on at least the primary communication channel. For example, this may involve transmitting and / or receiving data on the primary communication channel and, if available, on one or more additional channels, provided that the total bandwidth used remains within the bandwidth capability of the specific third apparatus and within the bandwidth capability of the apparatus with which it is communicating as the receiver of data.

[0118] According to one example of the third example embodiment, the frame indicates a duration of the timer. The frame may indicate the duration of the timer explicitly as a predefined value or dynamically based on network conditions. Alternatively, the timer duration may be represented through an encoded parameter, such as a scaling factor, offset, or reference to a previously agreed-upon duration. The indication may also beimplicit, inferred from other timing parameters within the frame, such as a contention window or a scheduling reference. By providing flexibility in how the timer duration is conveyed, this approach may enhance adaptability to varying network scenarios.

[0119] According to one example of the third example embodiment, the first apparatus may be configured to: perform a negotiation process with the specific third apparatus, the negotiation process resulting in determining a duration of the timer. Performing a negotiation process to determine the duration of the timer may allow for adaptive timing control, ensuring that the duration is optimized based on both network conditions and device-specific constraints.

[0120] According to one example of the third example embodiment, the first apparatus may be configured to perform the setting of the time window by at least sending a message addressed to an apparatus other than the first apparatus, wherein the message indicates the time window. For example, the message may be sent by the first apparatus to the set of apparatuses excluding the first apparatus. For example, the message may be sent by the first apparatus to the second apparatus and the specific third apparatus. The message may, for example, be sent via the primary communication channel.

[0121] According to one example of the third example embodiment, the negotiation process may, for example, involve the first apparatus sending a proposal to the specific third apparatus indicating a suggested duration for the timer. The specific third apparatus may then respond with an acknowledgment confirming the proposed duration or a counterproposal suggesting an alternative duration based on its operational requirements. This exchange may continue until an agreement is reached, at which point the final timer duration is determined provided in the frame by the first apparatus. This approach may ensure that the timer configuration is adaptive to both network conditions and device-specific constraints.

[0122] According to one example of the third example embodiment, the specific third apparatus may be configured to: receive a frame from the first apparatus indicative of a configuration of the timer, define the configuration of the timer based on the frame, wherein the configuration of the timer comprises at least one of the following: a start time of the timer, a duration of the timer, a stop time of the timer, or a restart time of the timer, and operatethe timer according the defined configuration. The start time may ensure that the timer begins counting at a predefined or dynamically assigned moment. The duration may dictate how long the timer remains active, defining the period during which a specific operation, such as staying on the secondary communication channel or delaying a switch, is maintained. The stop time may determine when the timer expires, triggering an event such as a transition to the primary communication channel. The restart time may allow the timer to reset and begin a new countdown or count-up. This approach may enable precise timing control, facilitating coordinated channel transitions.

[0123] According to one example of the third example embodiment, the start of the timer is a reception time of the start or of the end of the frame. The start of the frame may refer to the beginning of the frame which may be the moment when the first bit or symbol of the frame is received by the specific third apparatus. The end of the frame may refer to the moment when the last bit or symbol of the frame is received. By defining the timer’s start point relative to the frame reception, this example may enable precise timing control.

[0124] According to one example of the third example embodiment, the specific third apparatus may be configured to: stop the timer upon receiving the frame and restart the timer upon stopping the timer. The timer may, for example, be stopped at the moment when the first bit or symbol of the frame is received. By stopping the timer upon frame reception, the specific third apparatus may prevent unnecessary countdowns or increments e.g., when an update or new instruction is received. Restarting the timer after stopping, with a predefined threshold or minimal delay, may avoid dead time and unintended delays, ensuring continuous timing control and seamless execution of subsequent operations without disruption.

[0125] According to one example of the third example embodiment, the duration of the timer includes the time window and an additional time interval. The duration of the timer may be the sum of the durations of the time window and additional time interval. Including the additional time interval in the timer duration may enable a controlled switch to the primary communication channel after the time window has elapsed.

[0126] According to one example of the third example embodiment, the wireless communication system is a Wi-Fi system, and the additional interval comprises one or more shortinterframe spaces, SIFs, a contention period, and one or more SIFs. The additional interval comprises in sequence one or more SIFs, the contention period, and one or more SIFs. That is, the additional interval comprises the combined duration or is the sum of one or more SIFs, the contention period, and one or more SIFs.

[0127] According to one example of the third example embodiment, the start of the timer is the end of the time window. The timer may begin counting immediately after the time window expires, meaning that the timing mechanism is activated precisely at the end of the time window. This may ensure that subsequent actions, such as switching channels or initiating contention, follow a predefined schedule without delay or ambiguity.

[0128] According to one example of the third example embodiment, the wireless communication system is a Wi-Fi system, and the end of the time window is defined by expiration of a network allocation vector (NAV) timer. Using the NAV timer expiration to determine the end of the time window may enable seamless integration with existing Wi-Fi coordination mechanisms and may also allow it to be controlled together with other channel access and scheduling operations. A timer expiring or ending may mean that the timer has completed its predefined countdown or count-up duration.

[0129] According to one example of the third example embodiment, the specific third apparatus may be configured to: stop the timer upon receiving the frame and restart the timer at the end of the time window. The timer may, for example, be stopped at the moment when the first bit or symbol of the frame is received. This may enable controlled transition to the primary communication channel after the time window elapsed.

[0130] According to one example of the third example embodiment, the duration of the timer includes one or more SIFs, a contention period, and one or more SIFs. The duration of the timer may be the combined duration or is the sum one or more SIFs, the contention period, and one or more SIFs.

[0131] According to one example of the third example embodiment, the specific third apparatus may be configured to: in response to determining that the timer has expired during the time window, wait until the end of the time window to perform the switching. Waiting untilthe end of the time window to perform switching upon timer expiration may ensure orderly channel transitions and prevent premature disruption.

[0132] According to one example of the third example embodiment, the frame indicates the time window. The frame may, for example, indicate the time window by explicitly including information about its start time, duration, or end time. This may enable a multi-purpose function for the frame by not only facilitating precise timing synchronization but also supporting efficient scheduling.

[0133] According to one example of the third example embodiment, wherein the frame is any one of: a management frame, data frame, or beacon management frame. Allowing the frame to be any of a management frame, data frame, or beacon management frame may enable efficient integration with existing communication protocols while minimizing additional overhead.

[0134] According to one example of the third example embodiment, the wireless communication system may be a Wi-Fi system, but the disclosure is not limited to Wi-Fi alone. The wireless communication system may also be adapted for use in other wireless communication systems, such as cellular networks, and any other wireless protocols that involve managing access to a shared communication channel. The Wi-Fi system may, for example, operate in accordance with an IEEE 802.11 standard such as, for example, 802.11n, 802.11ac, 802.11ax, 802.11be, or802.11bn.

[0135] According to one example of the third example embodiment, the time window comprises a TXOP interval. Defining the time window as a TXOP interval may seamlessly integrate with existing medium access control mechanisms, wherein the setting of the time window may be performed at least according to an existing channel access procedure, such as EDCA.

[0136] According to one example of the third example embodiment, the first apparatus comprises an access point and remaining apparatuses of the set of apparatuses comprise non-AP STAs.According to one example of the third example embodiment, the set of apparatuses are part of a BSS of the wireless communication system, wherein the first apparatus comprisesan access point and remaining apparatuses of the set of apparatuses comprise non-AP STAs. The specific third apparatus may comprise a non-AP STA and the second apparatus may comprise a non-AP STA. The BSS may be an example implementation of the wireless network. In the multi-third apparatus communication example, each third apparatus of the subset of third apparatuses may be a non-AP STA.

[0137] According to one example of the third example embodiment, the first apparatus may be configured to allocate to the specific third apparatus the corresponding secondary communication channel. The allocation may further indicate the time window during which the specific third apparatus may be configured to communicate with the first apparatus on the corresponding secondary communication channel. In the multi-third apparatus communication example, the first apparatus may be configured to allocate to each third apparatus of the subset of third apparatuses the corresponding secondary communication channel. This process either performed for one third apparatus or for the subset of third apparatuses may be referred to as allocation operation.

[0138] According to one example of the third example embodiment, the allocation operation may refer to DSO, which may be referred to as DSO operation. The term sub-band may refer to a communication channel e.g., a secondary communication channel. The DSO operation may, for example, comprise the allocation operation. The initialization operation may provide parameters, configurations, or conditions that may be used for the execution of the DSO operation. The DSO operation may, for example, be enabled by exchanging between the first apparatus and the specific third apparatus an ICF which may be referred to as DSO ICF and a RCF which may be referred to as DSO RCF. In the multi-third apparatus communication example, the DSO operation may be enabled by using an ICF collectively for the subset of third apparatuses, while multiple RCFs may be provided by the subset of third apparatuses respectively. In case the time window is a TXOP, the TXOP may be referred to as DSO TXOP.

[0139] The present subject matter of the third example embodiment may improve the DSO operation by adapting the DSO operation. The adaptation of the DSO operation may be performed by, for example, adapting the initialization operation or the allocation operationof the DSO operation. The initialization operation may further include the first apparatus sending the frame to the specific third apparatus with instruction to switch to the primary communication channel after the end of the time window according to the timer. Alternatively, the allocation operation may further include the first apparatus sending the frame to the specific third apparatus with instruction to switch to the primary communication channel after the end of the time window according to the timer, wherein the frame may also be used for the allocation of the secondary communication channel(s).

[0140] According to one example of the third example embodiment, the frame sent by the first apparatus to the specific third apparatus with instruction to switch to the primary communication channel after the end of the time window according to the timer, may comprise a DSO ICF, data frame or acknowledgement frame.

[0141] According to one example of the third example embodiment, the first apparatus may be configured to send the frame to the specific third apparatus with instruction to switch to the primary communication channel after the end of the time window according to the timer in response to receiving information from the specific third apparatus, wherein the information may be provided in DSO RCF, data frame or acknowledgement frame.

[0142] According to one example of the third example embodiment, the first apparatus may comprise an AP and the specific third apparatus (or each third apparatus) may comprise a non-AP STA. In this context, the specific third apparatus may be referred to as DSO non-AP STA. The present subject matter may provide a mechanism to enable the AP and non-AP STA to negotiate a “DSO inactivity” timer, that triggers the non-AP STA’s return to the primary communication channel if, for example, the non-AP STA does not hear from its AP on the DSO location within that time. This may avoid the scenario where interference on the DSO location may leave the non-AP STA without the ability to communicate with the AP for an extended period of time.

[0143] According to one example of the third example embodiment, the timer may be dictated by the AP or negotiated on a “per non-AP STA” basis, and either option can be done in a variety of ways. It may be done during DSO initialization (e.g., during the initialization operation), which can occur during non-AP STA association and then re-run any time by having the AP or non-AP STA resend a DSO setup frame. However, this information mayalso be set by the AP and updated in the beacons or a management frame. This timer may also be set or updated by the AP in the ICF or by the non-AP STA in the RCF e.g., as part of the DSO operation.

[0144] According to one example of the third example embodiment, the non-AP STA with extended DSO enabled has a DSO timer (e.g., which counts upward) that shall be reset to '0' and (re-)started after the non-AP STA receives a DSO ICF from its AP. The specific start time can be set to: start or end of the DSO ICF received by the non-AP STA, start or end of the DSO RCF transmitted by the non-AP STA; start or end of the first data frame or acknowledgement (ACK) received from the AP in the DSO TXOP, or end of the DSO TXOP (per NAV). The value of the timer may be up to the implementer, but an example value may be based on when the timer is set to (re-)start. For example, if the timer (restarts when the DSO ICF is first received, the value may be set to the length of the DSO TXOP + SIFs + contention + SIFs. On the other hand, if the timer (re-)starts at the end of a DSO TXOP, the timer may be set to SIFs + contention + SIFs.

[0145] According to one example of the third example embodiment, the timer may always stop upon receiving a DSO ICF from the AP, regardless of when it is set to start. Thus, if the start time is the start of the DSO ICF, the timer stops, resets to ‘O’, and re-starts immediately. If, on the other hand, the start time is the end of the DSO TXOP, then the timer stops at the start of the DSO ICF and only restarts at the end of the DSO TXOP. In one example, the timer’s start and end times may be implemented as part of the definition of the timer itself, in which case these parameters may not need to be configured during DSO setup / initialization. With this timer, when DSO is enabled and the non-AP STA is in its DSO location, the non-AP STA may return to the primary communication channel when the timer expires. This may be useful in case the AP does not manage to capture the DSO location(s) within the time required by the non-AP STA (e.g., if the non-AP STA knows it carries low latency uplink traffic, it may set the timer to expire "SIFs + contention period + SIFs” after the current DSO TXOP), then the non-AP STA may return to the primary communication channel immediately with the AP’s knowledge.

[0146] According to one example of the third example embodiment, the AP and the non-AP STA may agree upon (or the AP sets) a “maximum DSO duration” after which the non-AP STA returns to the primary communication channel. Once this maximum duration is reached,the non-AP STA either waits until the end of the current DSO TXOP or until it sends a data / ACK frame with the end DSO flag before it returns to its primary location. This may avoid having the non-AP STA switch locations in the middle of receiving or transmitting a frame.

[0147] FIG. 1 illustrates an example wireless communication system in which the present subject matter may be implemented in accordance with an example. The wireless communication system 100 is a Wi-Fi system comprising a BSS including an access point AP1 and three non-AP STAs STA1 , STA2 and STA3.

[0148] As illustrated in FIG. 1 , the access point AP1 and the non-AP STA STA1 may be a pair of apparatuses that communicate using a communication channel, with one apparatus functioning as the transmitter and the other apparatus as the receiver. Furthermore, the access point AP1 and the non-AP station STA2 may be a pair of apparatuses that communicate using the communication channel, with one apparatus functioning as the transmitter and the other apparatus as the receiver. Furthermore, the access point AP1 and the non-AP STA STA3 may be a pair of apparatuses that communicate using a communication channel, with one apparatus functioning as the transmitter and the other apparatus as the receiver.

[0149] Hence, the access point AP1 and the non-AP STAs STA1 , STA2 and STA3 may form a set of apparatuses according to an example of the present subject matter.

[0150] The limited number of apparatuses is used for simplification and exemplification purposes, but the wireless communication system is not restricted to these specific components or quantities and may include additional or different apparatuses.

[0151] FIG. 2 is a flowchart of a method for using a primary communication channel of a wireless communication system in accordance with an example of the present subject matter. For the purpose of explanation, the method described in reference to FIG. 2 may be implemented in a first apparatus such as the access point illustrated and described in reference to FIG. 1 or apparatus illustrated and described in reference to FIG. 13 but is not limited to this implementation.In block 201 , a time window may be set during which the first apparatus is configured to communicate with a second apparatus on a primary communication channel of a wireless communication system and to communicate with a third apparatus on a corresponding secondary communication channel of the wireless communication system.

[0152] The third apparatus may be notified in block 203 to, after the time window has elapsed, further use the corresponding secondary communication channel or switch to the primary communication channel for communication.

[0153] FIG. 3 is a process block of a method for using a primary communication channel of a wireless communication system in accordance with an example of the present subject matter. For the purpose of explanation, the method described in reference to FIG. 3 may be implemented in a third apparatus such as the non-AP STA illustrated and described in reference to FIG. 1 or apparatus illustrated and described in reference to FIG. 13 but is not limited to this implementation.

[0154] The third apparatus may receive in block 301 from a first apparatus, a notification to, after a time window has elapsed, further use a corresponding secondary communication channel of a wireless communication system or switch to a primary communication channel of the wireless communication system for communication with the first apparatus; wherein, during the time window, the third apparatus is configured to communicate with the first apparatus the corresponding secondary communication channel and the first apparatus is configured to communicate with a second apparatus on the primary communication channel.

[0155] FIG. 4A is a diagram illustrating an example implementation of a notification frame according to the present subject matter. The notification frame may, for example, comprise a DSO ICF. The DSO ICF 400 may comprise a medium access control (MAC) header 401 and a frame body 402 containing various fields for data transmission. The MAC header 401 includes fields such as frame control field, which defines the frame type and control parameters, duration field, specifying the time required for the frame transmission, and receiver address (RA) and transmitter address (TA) fields, which identify the intended recipient and sender of the frame, respectively. The frame body contains common info field, a section applicable to all addressed devices in the frame, and a user info list field, which provides specific information for each addressed deviceindividually. Additionally, the frame includes padding, which may be used for alignment or timing adjustments, and an FCS field. The flag associated with the notification operation may be provided either in the common info field or the user info fields in the DSO ICF 400. The flag may be referred to as extended DSO flag.

[0156] More specifically, if the AP has the same extended DSO preference for all non-AP STAs involved in the DSO TxOP (e.g., the AP wants all the non-AP STAs involved in the DSO TxOP to remain in their DSO locations after the TxOP completes), it may only need one extended DSO flag, which may be placed in the common info field of the DSO ICF 400. The extended DSO preference may refer either to the instruction to further use the secondary communication channel, after the end of the TXOP or the instruction to switch to the primary communication channel, after the end of the TXOP. The extended DSO flag may be assigned to bit 63 of the common info field, which is currently reserved for all trigger frames as indicated in FIG. 4B. Alternatively, for any given DSO ICF (whether a newly defined DSO ICF or a DSO-enabled existing trigger frame), any of the labeled but reserved (i.e. , set to ‘0’ by default and ignored by the receiver) subfields of the common info field may be used to carry the extended DSO flag. For example, in the case of a DSO-enabled MU-RTS frame, all the highlighted subfields (B4 through B15 and B20 through B63) in FIG. 4B are considered reserved (i.e., unused). Any one of these subfields may be assigned the extended DSO flag, in which case a “1” vs. “0” in that subfield would indicate a request by the AP that all addressed non-AP STAs in DSO locations either remain there after the TXOP completes or return to the primary communication channel.

[0157] On the other hand, if the AP has different extended DSO preferences for the non-AP STAs involved in the DSO TXOP, the extended DSO flag may be inserted into reserved bit 39 at the end of each user info field in a basic trigger frame as shown in FIG. 4C. Alternatively, for any given DSO ICF, any of the labeled but reserved subfields (i.e., set to ‘0’ by default and ignored by the receiver) of the user info field may be used to carry the extended DSO flag. For example, in the case of a DSO-enabled MU-RTS frame, all the highlighted subfields (B20 through B39) in FIG. 4C are considered reserved (i.e., unused). Any one of these subfields could be assigned the extended DSO flag, in which case a “1” vs. “0” in that subfield would indicate a request by the AP that the specific non-AP STA either remain in its DSO location after the TXOP completes or return to the primary communication channel.

[0158] FIGs. 5 and 6 are diagrams each illustrating an example implementation of a response frame according to the present subject matter. The response frame may, for example, comprise a DSO RCF.

[0159] The DSO RCF (e.g., CTS and BSR) may not comprise a body. In this case, there are several subfields in the MAC header’s frame control field that serve no purpose. FIGs. 5 and 6 show the reserved (i.e. , unused) frame control subfields in CTS and BSR frames, respectively. When DSO is enabled, one of these subfields may be used forthe extended DSO flag that a non-AP STA may use to inform the AP of its intention to either remain in its DSO location or return to its primary channel after the current DSO TXOP. Since the “More Fragments”, “Retry”, “Protected Frame”, and “+HTC” subfields are reserved in both CTS and BSR frames, one of them may be used as the extended DSO flag in DSO RCFs.

[0160] FIG. 7 is a flowchart of a method for early transition from a secondary to a primary communication channel of a wireless communication system in accordance with an example of the present subject matter. For the purpose of explanation, the method described in reference to FIG. 7 may be implemented in a first apparatus such as the access point illustrated and described in reference to FIG. 1 or apparatus illustrated and described in reference to FIG. 13 but is not limited to this implementation.

[0161] In block 701 , it may be determined, by the first apparatus, that a communication process on a secondary communication channel, of the wireless communication system, between the first apparatus and a third apparatus terminates during a time window, wherein during the time window the first apparatus is configured to communicate with a second apparatus on a primary communication channel of the wireless communication system and to communicate with the third apparatus on the secondary communication channel.

[0162] The first apparatus may instruct in block 703 the third apparatus to, before the end of the time window, switch to the primary communication channel.

[0163] FIG. 8 is a process block of a method for early transition from a secondary to a primary communication channel of a wireless communication system in accordance with anexample of the present subject matter. For the purpose of explanation, the method described in reference to FIG. 8 may be implemented in a third apparatus such as the non-AP STA illustrated and described in reference to FIG. 1 or apparatus illustrated and described in reference to FIG. 13 but is not limited to this implementation.

[0164] The third apparatus may receive in block 801 from a first apparatus, an instruction to switch, before the end of a time window, to the primary communication channel of the wireless communication system to communicate with the first apparatus, wherein, during the time window, the third apparatus is configured to communicate with the first apparatus on a corresponding secondary communication channel of the wireless communication system and the first apparatus is configured to communicate with a second apparatus on the primary communication channel.

[0165] FIG. 9 is a diagram illustrating an example implementation of a data frame according to the present subject matter.

[0166] The data frame may for example be QoS data frame 900. The QoS data frame 900 comprises a MAC header, frame body and FCS field. The frame body may carry the data payload, while the FCS field may ensure data integrity by detecting transmission errors. The diagram illustrates the structure of the MAC header, detailing its various fields and their respective bit allocations. The MAC header comprises multiple sections, starting with the frame control field, which includes bits such as the protocol version, frame type, and subtype, followed by fields that may indicate whether the frame is destined to or from the distribution system (DS), fragment control, and retransmission status (Retry). The frame control field further comprises bits for power management, more data field, protected frame field and +HTC field. The MAC header also includes duration field, which may specify the time for which the channel is reserved, and up to four address fields (address 1-4), enabling device identification in different communication scenarios.

[0167] This structure may, for example, enable the AP and non-AP STA to use the more data bit in the frame control header to signal an end not only to data transmissions in the current DSO TXOP, but an end to the non-AP STA’s residence on the DSO location for the time being.

[0168] FIG. 10 is a diagram illustrating an example implementation of a block acknowledgement frame according to an example of the present subject matter.The block acknowledgement frame 1000 comprises a MAC header having the structure of the MAC header of the frame 400 described with reference to FIG. 4A. The block acknowledgement frame 1000 further comprises block acknowledgment (BA) control field, BA information field and FCS field.

[0169] As shown, the block acknowledgement frame 1000 contains frame control fields with several unused subfields, including the more fragments bit. The more fragments bit may, for example, be used as the end DSC flag, which the AP or non-AP STA can use to signal an end to data and ack exchanges between the AP and non-AP STA for the current DSC TXOP. This may release the non-AP STA to immediately return to its primary location rather than wait until the end of the DSC TXOP.

[0170] FIG. 11 is a flowchart of a method for time-based transition from a secondary to a primary communication channel of a wireless communication system in accordance with an example of the present subject matter. For the purpose of explanation, the method described in reference to FIG. 11 may be implemented in a third apparatus such as the non-AP STA illustrated and described in reference to FIG. 1 or apparatus illustrated and described in reference to FIG. 13 but is not limited to this implementation.

[0171] In response to determining in block 1110, by a third apparatus, that a timer has expired, the third apparatus may switch in block 1113, after the end of a time window, to a primary communication channel of a wireless communication system to communicate with a first apparatus, wherein during the time window the first apparatus is configured to communicate with a second apparatus on the primary communication channel and to communicate with the third apparatus on a secondary communication channel of the wireless communication system. In response to determining by the third apparatus that the timer has not expired, the third apparatus may continue using the secondary communication channel for communication with the first apparatus at least while the timer is still running.

[0172] FIG. 12 is a process block of a method for time-based transition from a secondary to a primary communication channel of a wireless communication system in accordance with an example of the present subject matter. For the purpose of explanation, the method described in reference to FIG. 12 may be implemented in a first apparatus such as theaccess point illustrated and described in reference to FIG. 1 or apparatus illustrated and described in reference to FIG. 13 but is not limited to this implementation.

[0173] A frame may be sent in block 1220 to a third apparatus with instruction to switch to a primary communication channel of a wireless communication system after the end of the time window, according to a timer whose configuration is indicated by a reception of the frame at the third apparatus, wherein during the time window the first apparatus is configured to communicate with a second apparatus on the primary communication channel and to communicate with the third apparatus on a secondary communication channel of the wireless communication system.

[0174] In FIG. 13, a block circuit diagram illustrating a configuration of an apparatus 1370 is shown, which is configured to implement at least part of the present subject matter. The apparatus may be a user equipment or an access point for wireless communication. It is to be noted that the apparatus 1370 shown in FIG. 13 may comprise several further elements or functions besides those described herein below, which are omitted herein for the sake of simplicity as they are not essential for the understanding. Furthermore, the apparatus may be also another device having a similar function, such as a chipset, a chip, a module etc., which can also be part of an apparatus or attached as a separate element to the apparatus 1370, or the like. The apparatus 1370 may comprise a processing function or processor, or controller 1371, such as a central processing unit (CPU) or the like, which executes instructions given by programs or the like related to a flow control mechanism. The processor 1371 may comprise one or more processing portions dedicated to specific processing as described below, or the processing may be run in a single processor. Portions for executing such specific processing may be also provided as discrete elements or within one or more further processors or processing portions, such as in one physical processor like a CPU or in several physical entities, for example. Reference sign 1372 denotes transceiver or input / output (I / O) units (interfaces) connected to the processor 1371. The I / O units 1372 may be used for communicating with one or more other network elements, entities, terminals or the like. The I / O units 1372 may be a combined unit comprising communication equipment towards several network elements or may comprise a distributed structure with a plurality of different interfaces for different network elements. Reference sign 1373 denotes a memory usable,for example, for storing data and instructions, such as programs to be executed by the processor 1371 and / or as a working storage of the processor 1371.

[0175] The processor 1371 is configured to execute processing related to the above described subject matter. In particular, the apparatus 1370 may be configured to perform the method as described in connection with FIG. 2, 3, 7, 8, 11, or 12.

[0176] As will be appreciated by one skilled in the art, aspects of the present invention may be embodied as an apparatus, method, computer program or computer program product. Accordingly, aspects of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit,” “module” or “system.” Furthermore, aspects of the present invention may take the form of a computer program product embodied in one or more computer readable medium(s) having computer executable code embodied thereon. A computer program comprises the computer executable code or "program instructions".

[0177] Any combination of one or more computer readable medium(s) may be utilized. The computer readable medium may be a computer readable storage medium. A ‘computer-readable storage medium’ as used herein encompasses any tangible storage medium which may store instructions which are executable by a processor of a computing device. The computer-readable storage medium may be referred to as a computer-readable non-transitory storage medium. The computer-readable storage medium may also be referred to as a tangible computer readable medium. In some embodiments, a computer-readable storage medium may also be able to store data which is able to be accessed by the processor of the computing device.

[0178] ‘Computer memory’ or ‘memory’ is an example of a computer-readable storage medium. Computer memory is any memory which is directly accessible to a processor. ‘Computer storage’ or ‘storage’ is a further example of a computer-readable storage medium. Computer storage is any non-volatile computer-readable storage medium. In some embodiments computer storage may also be computer memory or vice versa.A ‘processor1as used herein encompasses an electronic component which is able to execute a program or machine executable instruction or computer executable code. References to the computing device comprising “a processor” should be interpreted as possibly containing more than one processor or processing core. The processor may for instance be a multi-core processor. A processor may also refer to a collection of processors within a single computer system or distributed amongst multiple computer systems. The term computing device should also be interpreted to possibly refer to a collection or network of computing devices each comprising a processor or processors. The computer executable code may be executed by multiple processors that may be within the same computing device or which may even be distributed across multiple computing devices.

[0179] Computer executable code may comprise machine executable instructions or a program which causes a processor to perform an aspect of the present invention. Computer executable code for carrying out operations for aspects of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C++ orthe like and conventional procedural programming languages, such as the "C" programming language or similar programming languages and compiled into machine executable instructions. In some instances the computer executable code may be in the form of a high level language or in a pre-compiled form and be used in conjunction with an interpreter which generates the machine executable instructions on the fly.

[0180] Generally, the program instructions can be executed on one processor or on several processors. In the case of multiple processors, they can be distributed over several different entities. Each processor could execute a portion of the instructions intended for that entity. Thus, when referring to a system or process involving multiple entities, the computer program or program instructions are understood to be adapted to be executed by a processor associated or related to the respective entity.

Claims

54CLAIMS1. An apparatus, referred to as first apparatus comprising: at least one processor;and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus at least to:set a time window during which the first apparatus is configured to communicate with a second apparatus on a primary communication channel of a wireless communication system and to communicate with a third apparatus on a corresponding secondary communication channel of the wireless communication system; andnotify the third apparatus to, after the time window has elapsed, further use the corresponding secondary communication channel or switch to the primary communication channel for communication.

2. The apparatus of claim 1 , wherein the instructions, when executed by at least one processor, further cause the first apparatus to:receive from the third apparatus a response acknowledging or rejecting the further use of the corresponding secondary communication channel or the switching to the primary communication channel after the time window has lapsed; anddetermine a scheduling of resources for the third apparatus for a period after the time window based on the received response.

3. The first apparatus of claim 1, wherein the instructions, when executed by the at least one processor, further cause the first apparatus to:determine a scheduling of resources for the third apparatus for a period after the time window according to the notification.

4. The first apparatus of claim 1, wherein the instructions, when executed by the at least one processor, further cause the first apparatus to:determine a first scheduling of resources for the third apparatus for a period after the time window according to the notification;55receive from the third apparatus a response acknowledging or rejecting the further use of the corresponding secondary communication channel or the switching to the primary communication channel after the time window has lapsed; andadjust the first scheduling of resources for the third apparatus for the period after the time window according to the received response.

5. The first apparatus of any of the preceding claims, wherein the instructions, when executed by the at least one processor, further cause the first apparatus to:perform the setting of the time window by at least sending a message, addressed to an apparatus other than the first apparatus, the message indicating the time window.

6. The first apparatus of any of the preceding claims, wherein the instructions, when executed by the at least one processor, further cause the first apparatus to:perform the setting of the time window and the notification of the third apparatus by at least sending a same message indicating the time window and providing the notification to the third apparatus.

7. The first apparatus of any of the preceding claims, wherein the instructions, when executed by the at least one processor, further cause the first apparatus to:notify the third apparatus by at least sending a frame, addressed to the third apparatus.

8. The first apparatus of claim 7, the frame comprising a body and header, the body comprising a first field and a second field, the first field being applicable for all addressed apparatuses in the frame, and the second field being applicable per addressed apparatus in the frame, wherein the instructions, when executed by the at least one processor, further cause the first apparatus to perform at least one of the following:insert in the first field a flag indicating the notification, wherein the flag specifies whether the notification applies to a plurality of third apparatuses to further use the corresponding secondary communication channel or for the plurality of third apparatuses to switch to the primary communication56channel after the time window has lapsed, the plurality of third apparatuses comprising the third apparatus; orinsert in the second field an individual flag for a third apparatus of the plurality of the third apparatuses, the individual flag indicating whether the respective third apparatus is to further use the corresponding secondary communication channel or to switch to the primary communication channel after the time window has lapsed.

9. The first apparatus of any of the preceding claims, wherein the instructions, when executed by the at least one processor, further cause the first apparatus to:allocate to the third apparatus the corresponding secondary communication channel.

10. A method comprising:setting by a first apparatus a time window during which the first apparatus is configured to communicate with a second apparatus on a primary communication channel of a wireless communication system and to communicate with a third apparatus on a corresponding secondary communication channel of the wireless communication system; and Notifying, by the first apparatus, the third apparatus to, after the time window has elapsed, further use the corresponding secondary communication channel or switch to the primary communication channel for communication.

11. A computer program product comprising processor executable instructions for causing an apparatus to perform the method of claim 10.

12. An apparatus, referred to as third apparatus; the third apparatus comprising at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the third apparatus at least to: receive from a first apparatus, a notification to, after a time window has elapsed, further use a corresponding secondary communication channel of a wireless communication system or switch to a primary communication channel of the wireless communication system for communication with the first apparatus; wherein, during the time window, the third apparatus is configured to57communicate with the first apparatus the corresponding secondary communication channel and the first apparatus is configured to communicate with a second apparatus on the primary communication channel.

13. The third apparatus of claim 12, wherein the instructions, when executed by the at least one processor, further cause the third apparatus to:send to the first apparatus a response acknowledging or rejecting the further use of the corresponding secondary communication channel or switching to the primary communication channel.

14. The third apparatus of claim 13, wherein the instructions, when executed by the at least one processor, further cause the third apparatus to:send the response in a frame, the frame comprising a header and body.

15. The third apparatus of claim 14, the header comprising a flag in a reserved subfield of the header, the flag indicating the response.

16. The third apparatus of any of the preceding claims 13 to 15, wherein the instructions, when executed by the at least one processor, further cause the third apparatus to:switch to the primary communication channel or further use the secondary communication channel depending on the response.

17. The third apparatus of claim 12, wherein the instructions, when executed by the at least one processor, further cause the third apparatus to:switch to the primary communication channel or further use the secondary communication channel depending on the notification.

18. A method comprising:receiving by a third apparatus, from a first apparatus, a notification to, after a time window has elapsed, further use a corresponding secondary communication channel of a wireless communication system or switch to a primary communication channel of the wireless communication system for communication with the first apparatus; wherein the third apparatus is configured to communicate, during thetime window, with the first apparatus on the corresponding secondary communication channel and the first apparatus is configured to communicate with a second apparatus on the primary communication channel.

19. A computer program product comprising processor executable instructions for causing an apparatus to perform the method of claim 18.

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