Communication device and method for adjusting frequencies in the 6 GHz band

Abstract

The present disclosure provides a communications device and a communications method for performing frequency coordination in the 6 GHz band, the communications device comprising: a receiver that, in operation, receives information identifying an operating channel of an access point (AP) on a channel different from the operating channel, the information further indicating whether transmitting a probe request frame before receiving an enable signal on the operating channel is permitted; and circuitry that, in operation, determines from the information whether to generate a probe request frame to transmit before receiving an enable signal on the operating channel, the circuitry being further configured to scan the operating channel for an enable signal without transmitting a probe request frame based on a determination that transmitting a probe request frame before receiving an enable signal on the operating channel is not permitted.

Description

[Technical field]

[0001] The present disclosure relates to a communication device and a communication method that perform frequency adjustment, and more particularly, to a communication device and a communication method that perform frequency adjustment in the 6 GHz band. [Background technology]

[0002] The US Federal Communications Commission (FCC) recently opened up the 6 GHz band for unlicensed use, which will play a key role in achieving the throughput targets of upcoming wireless standards such as the IEEE 802.11ax (HE) standard, the IEEE 802.11be (EHT) standard, and the 3GPP 5G standard.

[0003] In an effort to protect current users, the FCC proposed rules in its latest Notice for Proposed Rulemaking (NPRM) regarding the operation of unlicensed devices in the 6 GHz band. This disclosure is particularly relevant to the following points in the NPRM:

[0004] - The U-NII-5 sub-band (5.925-6.425 GHz) and U-NII-7 sub-band (6.525-6.875 GHz) are widely used for point-to-point microwave links, including those that must maintain high availability. Therefore, in these sub-bands, "standard power access points (APs)" using power levels in the U-NII-1 and U-NII-3 bands are permitted to operate at frequencies determined by the Automated Frequency Coordination (AFC) system. U-NII stands for Unlicensed National Information Infrastructure.

[0005] - The U-NII-6 and U-NII-8 subbands are difficult to use for AFC because they are used by mobile stations whose current receiver locations cannot be easily determined from existing databases, so only indoor "low power access points" using the low power levels of the U-NII-2 band may be allowed in these subbands.

[0006] - Client devices may be allowed to operate across the entire 6 GHz band under the control of standard or low power APs.

[0007] However, there has been no discussion up to now about a communication device and a communication method that perform frequency adjustment in the 6 GHz band.

[0008] Therefore, there is a need for a communication device and method that provides a feasible technical solution for frequency coordination in the 6 GHz band.Furthermore, other desirable features and characteristics will become apparent from the following detailed description and appended claims, taken in conjunction with the accompanying drawings and the Background section of this disclosure. Summary of the Invention [Problem to be solved by the invention]

[0009] SUMMARY OF THE DISCLOSURE Non-limiting exemplary embodiments of the present invention facilitate providing a communications device and method for frequency coordination in the 6 GHz band. [Means for solving the problem]

[0010] According to a first embodiment of the present disclosure, there is provided a communications device comprising: a receiver that, in operation, receives information identifying an operating channel of an access point (AP) on a channel different from the operating channel, the information further indicating whether a probe request frame is permitted to be transmitted before receiving an enable signal on the operating channel; and a circuit that, in operation, determines from the information whether to generate a probe request frame to transmit before receiving an enable signal on the operating channel, the circuit being further configured to scan for an enable signal in the operating channel without transmitting a probe request frame based on a determination that a probe request frame is not permitted to be transmitted before receiving an enable signal on the operating channel.

[0011] According to a second embodiment of the present disclosure, there is provided an access point (AP) configured to advertise information of its operating channel on a channel different from the operating channel, the access point (AP) comprising: a circuit for generating, when operating, a signal including information indicating whether the AP is permitted to transmit a probe request frame before receiving an enable signal on the operating channel; and a transmitter for transmitting, when operating, the generated signal on the channel to one or more communication devices.

[0012] According to a third embodiment of the present disclosure, there is provided a communication method, comprising: receiving information identifying an operating channel of an access point (AP) on a channel different from the operating channel, the information further indicating whether a probe request frame is permitted to be transmitted before receiving an enable signal on the operating channel; determining based on the information whether to generate a probe request frame to be transmitted before receiving an enable signal on the operating channel; and scanning for an enable signal in the operating channel without transmitting a probe request frame based on a determination that a probe request frame is not permitted to be transmitted before receiving an enable signal on the operating channel.

[0013] It should be noted that the general or specific embodiments may be implemented as a system, a method, an integrated circuit, a computer program, a storage medium, or any combination thereof.

[0014] Further benefits and advantages of the disclosed embodiments will become apparent from the specification and drawings, and these benefits and / or advantages may be obtained by each embodiment and feature of the specification and drawings individually, and it is not necessary for all of these features to be present in order to obtain one or more of such benefits and / or advantages. [Brief description of the drawings]

[0015] Embodiments of the present disclosure will be better understood and readily apparent to those of ordinary skill in the art upon reading the following description, given by way of example only, and upon reference to the drawings in which: [Figure 1] 1 shows a schematic diagram of the architecture of an AFC system. [Diagram 2] 1 shows a flow diagram illustrating initial frequency availability inquiry and registration between an AP / AP controller and an AFC system. [Diagram 3] 2 shows an example of an AFC enabling signal according to each embodiment. [Figure 4] 13 shows the format of a Transmit Power Envelope element according to each embodiment. [Diagram 5] 2 shows a format of a trigger frame used as an AFC enable signal according to each embodiment. [Figure 6] FIG. 2 shows a schematic diagram of an enablement state machine according to various embodiments. [Figure 7]1 illustrates the format of a 6 GHz Operation Information field used to advertise AFC related information, according to embodiments. [Figure 8] 1 illustrates the format of a Reduced Neighbor Report element used to indicate whether active scanning is permitted in the 6 GHz band, according to embodiments. [Figure 9] 1 illustrates the format of a Neighbor Report element used to indicate whether active scanning is permitted in the 6 GHz band, according to embodiments. [Figure 10] 1 illustrates the format of a FILS (Fast Initial Link Setup) Discovery frame used to indicate whether active scanning is permitted in the 6 GHz band, according to embodiments. [Figure 11] 1 shows a flow diagram illustrating an interference cancellation mechanism in the 6 GHz band according to various embodiments. [Figure 12] 1 illustrates a format of a Cease Transmission Control frame used for interference cancellation according to each embodiment. [Figure 13] 1 illustrates the format of a Cease Transmission element used for interference cancellation according to embodiments. [Figure 14] 1 illustrates a schematic example of a communication device according to embodiments. The communication device may be implemented as an AP or a STA and may be configured to perform frequency coordination in the 6 GHz band according to embodiments of the present disclosure. [Figure 15] 1 shows a flow diagram illustrating a communication method according to embodiments. [Figure 16] 1 illustrates a configuration of a communication device (eg, a communication apparatus or a station (STA)) according to each embodiment. [Figure 17]2 illustrates a configuration of a communication device (eg, AP) according to each embodiment.

[0016] Those skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some elements in the illustrations, block diagrams, or flow charts may be exaggerated relative to other elements to facilitate an accurate understanding of the embodiments of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Some embodiments of the present disclosure will now be described, by way of example only, with reference to the drawings in which like reference numbers and characters indicate similar or equivalent elements, and in which:

[0018] In the following paragraphs, a particular exemplary embodiment is described with reference to an access point (AP) and a station (STA) for enhanced direct link communication.

[0019] In the context of IEEE 802.11 (Wi-Fi) technology, a station (also synonymously referred to as a STA) is a communication device capable of using the 802.11 protocol. Based on the definition in IEEE 802.11-2016, a STA can be any device that includes an IEEE 802.11-compliant medium access control (MAC) and physical layer (PHY) interface to the wireless medium (WM).

[0020] An STA may be, for example, a notebook, a desktop personal computer (PC), a personal digital assistant (PDA), an access point, or a Wi-Fi phone in a wireless local area network (WLAN) environment. An STA may be stationary or mobile. In a WLAN environment, the terms "STA", "wireless client", "user", "user device", and "node" are often used synonymously.

[0021] Similarly, an AP (also synonymously known as a Wireless Access Point (WAP) in the context of IEEE 802.11 (Wi-Fi) technology) is a communications device that allows STAs in a WLAN to connect to a wired network. APs are typically connected to a router (through the wired network) as standalone devices, but APs can also be integrated with or used within a router.

[0022] As mentioned above, a STA in a WLAN can function as an AP in other cases, and vice versa. The reason for this is that a communication device in the context of IEEE 802.11 (Wi-Fi) technology may include both STA hardware components and AP hardware components. In this way, the communication device can switch between STA mode and AP mode based on the actual WLAN conditions and / or requirements.

[0023] The Notice of Proposed Rulemaking (NPRM) [2] (https: / / docs.fcc.gov / public / attachments / FCC-18-147A1.pdf) proposes to amend the rules of Title 47, Part 15, subpart E (operation of U-NII devices in the 5 GHz band) of the Code of Federal Regulations (CFR) [7] (https: / / www.govregs.com / regulations / title47_chapterI_part15_subpartE). Some of the relevant rules are shown below.

[0024] - The AFC system is a system in which an access point automatically determines and provides a list of available frequencies in the U-NII-5 subband (5.925 to 6.425 GHz) and U-NII-7 subband (6.525 to 6.875 GHz).

[0025] A client device is a U-NII device that typically transmits under the control of an access point and cannot initiate a network.

[0026] - An access point operating in the U-NII-5 and U-NII-7 subbands shall, prior to transmission, contact the AFC system to determine which frequencies are available in its geographic coordinates. The access point may only transmit on those frequencies indicated as available by the AFC system.

[0027] - Operation of access points in the 6 GHz band is prohibited in moving vehicles such as cars, trains, and aircraft.

[0028] - Operation in the 6 GHz band is prohibited for control of or communication with unmanned aerial systems.

[0029] Additionally, the FCC is seeking comment on whether client devices should be permitted to actively scan channels in the U-NII-5 and U-NII-7 subbands before receiving an "enable signal."

[0030] Similarly, regulatory bodies in other regions, such as ETSI in Europe, are actively planning to open up portions of the 6 GHz band for unlicensed use and may propose rules like the one above in their own regions.

[0031] Therefore, the present invention proposes a procedure for operating an 802.11 Basic Service Set (BSS) under the control of an AFC system in the 6 GHz band, and focuses on the operation of the 802.11 BSS from the perspective of the interaction between the AP and the AFC system, and between the AP and STAs.

[0032] Unlicensed users, such as IEEE 802.11 access points, must contact the AFC system to seek approval to operate their wireless networks when operating in a portion of the 6 GHz band (e.g., the U-NII-5 or U-NII-7 sub-bands). Figure 1 shows a schematic diagram 100 illustrating an example of a wireless network operating under the AFC system.

[0033] - The central AFC database 102 contains information of all current licensed users. The AFC database 102 can be a central or distributed database that maintains a record of all licensed users within a geographical area, and includes current users' transmitter and receiver information such as location, altitude, azimuth, elevation angle (tilt), assigned frequencies, antenna size, etc., and may be maintained by a government regulatory agency (e.g., FCC).

[0034] - one or more AFC systems (e.g. 104 and 106). The AFC system may determine and provide a list of frequencies that the 802.11 BSS can use (e.g. based on calculations of interference that the BSS may cause to nearby incumbent receivers). For this purpose, the AFC system may use information of the incumbent receivers from the AFC database 102 and information of the 802.11 APs, such as their location, altitude, maximum transmit power, and other similar information. The AFC system may also record the frequencies used after being selected by the 802.11 BSS and may have a connection with the systems of the incumbent users (e.g. for interference reporting). The AFC system may be operated by a private company.

[0035] - In the simplest case, a standalone access point such as AP 110 can directly connect to the AFC system (e.g., via the Internet), inquire about the availability of frequency resources, and request approval to operate a wireless network on a permitted frequency.

[0036] In more advanced cases (e.g., enterprise or managed networks), multiple access points such as APs 112 and 114 can connect to the AFC system via a proxy device (e.g., AP controller 108). The AP controller 108 can be a physical device or a logical controller such as a cloud-based AP manager. The AP controller 108 can negotiate with the AFC system 104 on behalf of one or more 802.11 BSSs 116 and 118 and can represent multiple access points such as APs 112 and 114 when interacting with the AFC system 104. IEEE 802.11 wireless networks and access points are shown in this figure as examples of unlicensed users. Another example of an unlicensed user can be a cellular network with base stations acting as access points to cooperate with the AFC system.

[0037] An important difference between the AFC system in the U-NII-5 and U-NII-7 sub-bands and other similar systems based on databases, such as TVWS (TV White Space) systems, is that in the TVWS spectrum, the database only holds information about licensed transmitters (e.g. TV broadcast stations) and not about receivers. The receivers cannot record their information, since they are passive receivers (e.g. TV). Thus, in TVWS, as long as a licensed transmitter is operating in a certain area in a certain frequency range, all areas that could potentially receive the transmitted signal are considered unavailable for TVWS equipment / networks, regardless of whether there are actually receiving equipment present. This can be considered an overprotective system. However, in the U-NII-5 and U-NII-7 sub-bands, most of the licensed users are fixed service point-to-point systems (e.g. fixed service microwave systems), and it is possible to hold detailed information of all licensed receivers in the AFC database. This allows the AFC system to accurately calculate whether an access point (and its client device) will cause harmful interference to a licensed receiver, provided that the access point information (antenna location, antenna height, transmission power, etc.) is provided. For example, if an unlicensed network happens to be within the boresight of a licensed receiver's antenna and close enough to the receiving antenna, the AFC system can determine that the unlicensed network causes interference to licensed users within the frequency range allocated to the licensed users. The AFC system can also use topographic information (topography, presence of tall buildings and trees, etc.) to more accurately predict interference to licensed users. Although these details are still being worked out, it is likely that the AFC system will require much more sophisticated interference calculation capabilities than traditional systems (such as TVWS). This means that the 6 GHz band is expected to have a much higher frequency spectrum reuse rate.However, this also means that the risk of inadvertent interference with licensed users increases, so AFC systems must implement additional measures to protect incumbent users in the event of inadvertent interference (e.g. provisions for incumbent users to report interference), and must have the ability to quickly identify unlicensed networks that are causing interference and instruct them to stop transmitting when they are interfering.

[0038] FIG. 2 illustrates a flow diagram 200 illustrating a method an access point (AP) may use to initiate a wireless network (also referred to as a Basic Service Set (BSS) or commonly as a Radio Local Area Network (RLAN)) in a regulated sub-band of the 6 GHz band (such as the U-NII-5 or U-NII-7 sub-band).

[0039] At 202, the AP sends a first message (e.g., Frequency Availability Query) to the AFC system to inquire about the availability of a desired frequency range. This message may include the AP's identification information (e.g., regulatory agency provided ID such as FCC ID or ETSI ID, WLAN MAC address), the AP's geolocation (latitude, longitude, altitude), the AP's antenna information (elevation angle, beam width, maximum output power), and the desired frequency range.

[0040] At 204, the AFC system can verify whether the AP is allowed to operate in the area based on the information of the AP, and can further calculate whether the AP or any of the client devices under the control of the AP interfere with the current receiver in the AFC database. The AFC system can send a second message (e.g., a Frequency Availability Response) to the AP to inform the result of the determination. This message can include the available frequency range that the AP can use for the RLAN and the corresponding maximum transmit power that can be used in the frequency range.

[0041] At 206, the AP may select a channel (frequency subset) for its BSS from the frequency range provided in the Frequency Availability Response and send a third message (e.g., an AP Registration Request) to the AFC system to register the unlicensed use of the frequency subset. This message may include the AP's identification information and the selected frequency subset. If interference is reported by a licensed user, the AFC system may use this information to identify the source of interference.

[0042] At 208, the AFC system may record the AP's information (identification, selected frequency subset) in the system and send a fourth message (e.g., AP Registration Response) to the AP. This message may indicate the status of the registration request and may optionally include a re-registration timeout. The re-registration timeout may be a dynamic value determined by the AFC system or may be a fixed value (e.g., 24 hours) specified by a regulatory body. In order to continue using the selected frequency, the AP must re-register itself before the timeout value. The AFC system may also indicate whether active scanning is permitted in the selected frequency subset (i.e., whether a client device is permitted to transmit a probe request frame before receiving an indication from the AP that the channel may be used for transmission). Alternatively, in the more general case, the AFC system may indicate whether an initial transmission from a client device is permitted before receiving an indication from the AP that the channel may be used for transmission.

[0043] At 210, upon receiving the AP registration response with a success status, the AP may initiate a BSS or RLAN on the selected channel.

[0044] After starting a BSS on a channel of the U-NII-5 and U-NII-7 subbands, the AP needs to periodically transmit a signal on the working channel of the BSS to inform its associated client devices (STAs) or potential client devices that it is safe to use the working channel for wireless communication with the AP. This signal can be called an enable signal, a permission signal, or the like. Any frame that the AP periodically transmits on the working channel of the BSS can be considered as an enable signal, but for safety reasons, an explicit signal (e.g., 1 bit) called an AFC Inband Enabling Signal can be included in the Beacon frame transmitted by the AP. FIG. 3 shows an example of an AFC enabling signal 300 according to each embodiment. When a bit of the AFC enabling signal 300 is set to 1, it can indicate that the frame carrying the AFC enabling signal is an AFC enabling signal.

[0045] As will be further explained below, another frame, such as a Probe Response frame, a FILS Discovery frame, or a Trigger frame, may also act as the enabling signal by carrying an AFC Inband Enabling Signal 300. Any of these frames carrying an AFC Inband Enabling Signal 300 set to 1 may be considered an enabling signal by the receiving client device. Regulatory bodies may mandate that client devices are not allowed to transmit anything in the U-NII-5 and U-NII-7 subbands, including interrogation frames such as Probe Request frames, before receiving a valid enabling signal.

[0046] In addition to advertising an enable signal, an AP may also advertise transmit power limitations that apply on the operating channels of the BSS, for example by including a Transmit Power Envelope element in a Beacon or Probe Response frame. Figure 4 illustrates the format of a Transmit Power Envelope element 400 according to embodiments. The transmit power envelope element 400 includes an element ID field, a length field, a transmit power information field, a local maximum transmit power for 20 MHz field, a local maximum transmit power for 40 MHz field, a local maximum transmit power for 80 MHz field, a local maximum transmit power for 160 / 80+80 MHz field, a local maximum transmit power for 240 / 80+160 MHz field, a local maximum transmit power for 320 / 160+160 MHz field, and a local maximum transmit power for 320 / 160+160 MHz field. Additionally, the Transmit Power Information field may include (or consist of) a Local Maximum Transmit Power Count field, a Local Maximum Transmit Power Unit Interpretation field, and a Reserved field.

[0047] The Transmit Power Envelope element 400 may indicate the local maximum transmit power for all applicable channel bandwidths, including 240 MHz or 160+80 MHz channels and 320 MHz or 160+160 MHz channels being considered by the 802.11be task group. The Local Maximum Transmit Power Count field may indicate the number of local maximum transmit power fields included in the element. For example, a value of n indicates that there are n+1 fields, where the value of n may be as shown in the table of FIG. 4. Each of the Local Maximum Transmit Power for X MHz fields may be encoded as an 8-bit 2s complement signed integer ranging from -64 dBm to 63 dBm in 0.5 dB steps. A value of 63.5 dBm may indicate 63.5 dBm or greater (i.e., no local maximum transmit power constraint exists). A client station is not permitted to transmit at a power greater than the value indicated in each applicable field of the Transmit Power Envelope element.

[0048] 5 shows the format of a Trigger frame 500 for use as an AFC in-band enable signal according to embodiments. The Trigger frame 500 may include (or consist of) a Frame Control field, a Duration field, an RA field, a TA field, a Common Info field, one or more User Info fields, a Padding field, and an FCS field. The Frame Control field may include (or consist of) a Protocol Version field, a Type (Control) field, a Subtype field, a To DS (0) field, a From DS (0) field, a More Frag (0) field, a Retry (0) field, an AFC Inband Enabling Signal field, a More Data field, a Protected Frame (0) field, and a +HTC (0) field. All Trigger frames transmitted in the U-NII-5 and U-NII-7 subbands may be considered as AFC Enabling signals for the addressed STA, or the Trigger frame may explicitly convey an "AFC Inband Enabling Signal" as indicated by the AFC Inband Enabling Signal field of Trigger frame 500. As an example, an unused bit (eg, B12 (power management)) in the Frame Control field of a Trigger frame can be overloaded as an "AFC in-band enable signal."Furthermore, a trigger frame with the "AFC in-band enable signal" set to 1 can be considered as a special enable signal, which allows the associated STA to remain in the AFC Enabled state without the need to receive Beacon frames periodically.

[0049] FIG. 6 shows a schematic diagram of an enablement state machine 600 according to various embodiments. The enablement state machine 600 is a state that a non-AP STA can maintain to track its AFC enablement state in the U-NII-5 and U-NII-7 sub-bands, and can include at least an Unenabled state 602 and an Enabled state 604. A non-AP STA in the Unenabled state 602 does not transmit any frames on the channels in the U-NII-5 and U-NII-7 sub-bands, except for a probe request frame if active scanning is allowed by the AFC system. Alternatively, in the more general case, if the AFC system indicates that initial transmissions of a particular category are allowed from a client device in the Unenabled state 602, the client device is allowed to transmit frames of the selected category (e.g., a generic advertisement service public action frame, etc.). These frames are pre-association frames used by client devices to discover the capabilities of an AP or to discover services provided by a back-end system to which the AP is connected. A non-AP STA may transition to the Enabled state 604 upon receiving an enable signal, such as an AFC in-band enable signal carried in a Beacon frame, a Probe Response frame, a FILS Discovery frame, or a Trigger frame. Additionally, a non-AP STA may reset an AFC Enablement Validity Timer 606 to a value equal to the value of AFC_ENABLEMENT_PERIOD each time it receives an AFC in-band enable signal.In one embodiment, the value of AFC_ENABLEMENT_PERIOD may be received via a signal from an associated AP, and the value of AFC_ENABLEMENT_PERIOD may be defined by the AP, hi another embodiment, AFC_ENABLEMENT_PERIOD may be a fixed value defined in the IEEE 802.11 standard.

[0050] When a non-AP STA is in the Enabled state 604, for example, - A non-AP STA receives a Cease Transmission instruction - A non-AP STA receives an (Extended) Channel Switch Announcement element with the Channel Mode field set to 1. - the non-AP STA fails to receive an AFC in-band enable signal for a period equal to AFC_ENABLEMENT_PERIOD; If the STA is in a power save mode and has been in a doze state for AFC_ENABLEMENT_PERIOD or more, it may return to the Unenabled state 602. This also applies to STAs in a power save mode that have been in a doze state for AFC_ENABLEMENT_PERIOD or more. A non-AP STA may return to the AFC Enabled state upon receiving a Trigger frame carrying an AFC in-band enable signal. The Trigger frame may be in the format of the Trigger frame 500 shown in FIG. 5.

[0051] In the U-NII-5 and U-NII-7 sub-bands, client devices (e.g., non-AP STAs) must receive an enable signal at regular intervals to remain in the AFC Enabled state. If the device fails to receive a valid enable signal for a certain period of time, e.g., longer than AFC_ENABLEMENT_PERIOD, the device transitions to an Unenabled state where no transmission is permitted. For devices operating in active mode (i.e., not in a power-saving mode), this is not an issue since they can expect to receive Beacon frames periodically. However, in certain power-saving modes, non-AP STAs are permitted to remain in a doze state without receiving frames from the AP for an extended period of time in order to conserve battery power. Non-AP STAs can only wake up when they receive an indication of buffered frames from the AP. When operating in some other power saving modes, e.g., Triggered Target Wake Time (TWT), the non-AP STAs wake up only for a certain time period and expect to receive a Trigger frame from the AP at the beginning of the TWT time period. If the AFC_ENABLEMENT_PERIOD is short, the non-AP STAs operating in the power saving mode must wake up frequently to receive an enable signal (e.g., a Beacon frame), which may result in power waste. The Trigger frame can also be qualified as an enable signal for the associated non-AP STAs, so that the non-AP STAs in the power saving mode can continue in the AFC Enabled state without having to wake up for a Beacon frame.All Trigger frames may be considered as an enable signal by default, or the Trigger frame may explicitly carry an AFC in-band enable signal bit, for example in the Frame Control field of Trigger frame 500 as shown in Figure 5. When a non-AP STA wakes up and receives a Trigger frame, if it is still in the AFC Enabled state, it may reset the AFC Enablement Validity Timer to AFC_ENABLEMENT_PERIOD, or if it has already transitioned to the Unenabled state, it may return to the AFC Enabled state and send an uplink frame in response to the received Trigger frame.

[0052] By default, transmission of frames, including discovery frames such as Probe Request frames, is not permitted before receiving an AFC enable signal. Transmission of Probe Request frames before receiving an AFC enable signal is permitted only on channels that explicitly allow active scanning. An AP can indicate whether active scanning is permitted before receiving an AFC enable signal, for example, in the 6 GHz Operation Information field in the HE Operation element conveyed in a Beacon frame or Probe Response frame transmitted in the 6 GHz band. Alternatively, in the more general case, an AP can indicate that initial transmissions of a particular category (e.g., GAS (General Advertisement Service) Public Action frames, Probe Request frames) are permitted before a client device receives an AFC enable signal.

[0053] 7 illustrates a format of a 6 GHz Operation Information field 700 used to advertise AFC related information according to embodiments. The 6 GHz Operation Information field 700 may include (or consist of) a Primary Channel field, a Control field, a Channel Center Frequency Segment 0 field, a Channel Center Frequency Segment 1 field, a Minimum Rate field, and an AFC Information field. The Control field may include (or consist of) a Channel Width field, an AFC Information Present field indicating whether the AFC Information field is present, and a Reserved field. The AFC Information field may include (or consist of) an AFC Enablement Period field and an Active Scan Allowed signal field. For example, a value of "0" in the Active Scan Allowed field may indicate that active scanning is not allowed on the indicated channel prior to receiving the AFC enable signal, and a value of "1" may indicate that active scanning is allowed on the indicated channel prior to receiving the AFC enable signal.

[0054] The AP may decide whether to allow active scanning based on an explicit instruction by the AFC system at AP registration time, or it may decide implicitly, for example based on the maximum transmit power allowed on the channel. If the maximum transmit power is below a certain threshold, the AP may infer that the current receiver may be located nearby and may decide not to allow active scanning before receiving an enable signal.

[0055] When operating in the U-NII-5 and U-NII-7 subbands, the AP may also advertise information related to AFC operation in a beacon frame or a probe response frame transmitted in the 6 GHz band, for example by including an AFC Information field in the 6 GHz Operation Information field in the HE Operation element or the EHT Operation element, in addition to other operation parameters. Such a 6 GHz Operation Information field may have the same format as the 6 GHz Operation Information field 700 shown in FIG. 7. The presence of the AFC Information field implicitly indicates that operation on the channel indicated in the 6 GHz Operation Information field is subject to the control of the AFC system, and non-AP STAs operating in a BSS operated by such an AP must follow the AFC state machine shown in FIG. 6 above. The AFC Information field may convey, among other things, an AFC Enablement Period field indicating a value of AFC_ENABLEMENT_PERIOD, and an Active Scan Allowed field indicating whether active scanning is permitted on the operating channel of the BSS (i.e., whether non-AP STAs are permitted to transmit Probe Request frames prior to receiving an enable signal). For example, a value of "0" in the Active Scan Allowed field may indicate that active scanning is not permitted on the indicated channel prior to receiving an AFC enable signal, and a value of "1" may indicate that active scanning is permitted on the indicated channel prior to receiving an AFC enable signal.Information regarding active scanning may also be used by neighboring APs to generate in-band or out-of-band Neighbor Report elements, Reduced Neighbor Report elements, and the like.

[0056] FIG. 8 illustrates a possible format of a Reduced Neighbor Report element, and FIG. 9 illustrates a possible format of a Neighbor Report element. FIG. 8 illustrates a format of a Reduced Neighbor Report element used to indicate whether active scanning is allowed in the 6 GHz band according to embodiments. The Reduced Neighbor Report element may include (or consist of) an Element ID field, a Length field, a TBTT Information Header field, an Operating Class field, a Channel Number field, and a TBTT Information Set field. The TBTT Information Set field may include (or consist of) a Neighbor AP TBTT Offset field, a BSSID (optional) field, a Short-SSID (optional) field, and a BSS Parameters (optional) field. Additionally, the BSS Parameters (optional) field may include (or consist of) an OCT Recommended field, a Member of Co-located ESS field, a 20 TU Probe Response Active field, and an Active Scan Allowed field.

[0057] 9 illustrates a format of a Neighbor Report element 900 used to indicate whether active scanning is allowed in the 6 GHz band, according to embodiments. The Neighbor Report element 900 can include (or consist of) an Element ID field, a Length field, a BSSID field, a BSSID Information field, an Operating Class field, a Channel Number field, a PHY Type field, and an Optional Subelements field. The BSSID Information Set field can include (or consist of) an AP Reachability field, a Co-located AP field, a 20 TU Probe Response Active field, and an Active Scan Allowed field.

[0058] The 6 GHz band is a newly opened frequency band for unlicensed use, but there are currently no unlicensed users in this band. Also, in consideration of possible restrictions, attempts have been made to reduce the transmission of management frames in this band, especially frames related to initial discovery, such as Probe Request frames. Probe Request frames are management frames used by non-AP STAs to discover the presence of APs operating on a channel. The IEEE 802.11ax standard introduces various mechanisms to reduce the transmission of management frames related to initial AP discovery. One such mechanism is out-of-band advertising of co-located APs. Generally, infrastructure AP devices operate as multiple APs simultaneously in multiple frequency bands, such as 2.4 GHz, 5 GHz, and 6 GHz, and such APs are known as co-located APs. An AP operating in the 2.4 GHz or 5 GHz band can advertise that it also operates in the 6 GHz band by including information about the 6 GHz co-located AP in a Reduced Neighbor Report (RNR) or Neighbor Report element in a Beacon or Probe Response frame. The Reduced Neighbor Report element can be in the same format as the Reduced Neighbor Report element 800 shown in Figure 8, and the Neighbor Report element can be in the same format as the Neighbor Report element 900 shown in Figure 9.

[0059] In addition to the operating parameters of the 6 GHz co-located AP, the Reduced Neighbor Report (RNR) and Neighbor Report elements may also indicate whether active scanning is allowed on the operating channel of the 6 GHz BSS of the co-located AP, for example, by indicating a value in the Active Scan Allowed field shown in the Reduced Neighbor Report element 800 or Neighbor Report element 900. For example, a value of "0" may indicate that active scanning is not allowed on the indicated channel prior to receiving an AFC enable signal, and a value of "1" may indicate that active scanning is allowed on the indicated channel prior to receiving an AFC enable signal. Non-AP STAs can receive information about co-located 6 GHz APs through Beacon frames in the 2.4 GHz or 5 GHz bands, or they can request such information by sending Probe Request frames to the 6 GHz APs in the 2.4 GHz or 5 GHz bands using the On-Channel Tunneling (OCT) protocol. Additionally, APs can advertise information about neighboring APs (i.e., non-co-located APs) operating in the 6 GHz band in an abbreviated Neighbor Report (RNR) element or a Neighbor Report element.

[0060] Another mechanism introduced in the IEEE 802.11ax standard to reduce the transmission of management frames related to initial AP discovery is the introduction of preferred scanning channels (PSCs) in the 6 GHz band. PSCs are 20 MHz channels occurring at 80 MHz intervals in the 6 GHz band, and 6 GHz APs can transmit Fast Initial Link Setup (FILS) Discovery frames on the PSCs at regular intervals to advertise that they are operating in the 6 GHz band. Figure 10 shows the format of a FILS Discovery frame 1000 according to various embodiments. The FILS Discovery frame 1000 may include (or consist of) a FILS Discovery Frame Control field, a Timestamp field, a Beacon Interval field, an SSID / Short SSIID field, a Length field, an FD Capability field, an Operating Class field, a Primary Channel field, and a Mobility Domain field. The FD Capability field may include (or consist of) an ANO Presence Indicator field, a Primary Channel Presence Indicator field, an MD Presence Indicator field, and an Active Scan Allowed field.

[0061] The FILS Discovery frame is a simplified version of a Beacon or Probe Response frame, but is transmitted much more frequently, for example, once every 20 TUs (time units), where 1 TU is equal to 1024 microseconds. This allows non-AP STAs to perform high-speed passive scanning in 6 GHz by focusing passive scanning on the PSC. The PSC can be the same as the operating channel of the 6 GHz AP, but if different, the AP can also advertise whether active scanning is allowed on its operating channel by including an Active Scan Allowed field in the FILS Discovery frame, for example, by including an Active Scan Allowed field in the FILS Discovery frame 1000 of FIG. 10. For example, a value of "0" in the Active Scan Allowed field may indicate that active scanning is not allowed on the indicated channel prior to receiving the AFC enable signal, and a value of "1" may indicate that active scanning is allowed on the indicated channel prior to receiving the AFC enable signal.

[0062] When a non-AP STA receives information about active scanning on a channel different from the working channel of the AP in the 6 GHz band, if the Active Scan Allowed field indicates that active scanning is not allowed, it does not transmit anything (including a Probe Request frame) on the working channel in the 6 GHz band, but performs passive scanning on the working channel and waits for an enable signal (e.g., a Beacon frame). Only if the Active Scan Allowed field indicates that active scanning is allowed on the working channel, the non-AP STA can transmit a Probe Request frame on the working channel in the 6 GHz band.

[0063] AFC systems are likely to require much higher interference calculation capabilities than conventional systems (such as TVWS), and therefore much higher reuse of the 6 GHz frequency spectrum. However, this means that the risk of inadvertent interference with licensed users may also increase, in which case AFC systems will need to implement additional measures to protect incumbent users in case of inadvertent interference. For example, there will need to be provisions for incumbent users to report interference, and the AFC system will need to have the ability to quickly identify unlicensed networks causing interference and to instruct them to stop interfering transmissions.

[0064] An example of such a mechanism for interference mitigation is shown in Figure 11, which shows a flow diagram 1100 illustrating a mechanism for interference cancellation in the 6 GHz band, according to embodiments. At 1102, an incumbent user detects an interference condition and sends an interference report to an associated AFC system. At 1104, the AFC system identifies the interfering AP and sends a cease operation instruction to the AP, optionally including an alternative frequency for the AP to use. At 1106, upon receiving the cease operation instruction, the AP immediately ceases all transmissions in its BSS and, if an alternative frequency has been provided, transitions the BSS to a new channel within the alternative frequency. However, if an alternative frequency has not been provided by the AFC system and the AP cannot immediately identify another candidate channel, the AP can instruct associated non-AP STAs to cease all transmissions in the BSS by transmitting a Cease Transmission frame.

[0065] The Cease Transmission frame may be, for example, in the format of a Cease Transmission Control frame 1200 as shown in FIG. 12, or may be a frame conveying an element in the format of a Cease Transmission element 1300 (conveyed in a management frame) as shown in FIG. 13. The Cease Transmission Control frame 1200 may include (or consist of) a Frame Control field, a Duration field, an RA field identifying the address of the receiver, a TA field identifying the address of the transmitter, a BSSID field identifying the BSS, a Next Action field, and an FCS field. The Cease Transmission element 1300 may include (or consist of) an Element ID field, a Length field, an Extended Element ID field, a BSSID field identifying the BSS, and a Next Action field.

[0066] In each embodiment, upon receiving a cease transmission instruction from the associated AP, the non-AP STA immediately ceases all transmissions on the channel and performs the next step as instructed by the AP. The next step may be indicated in a Next Action field present in the Cease Transmission Control frame 1200 of Figure 12 and the Cease Transmission element 1300 of Figure 13. Table 1 below shows examples of possible next steps. [Table 1]

[0067] For example, if the Next Action field indicates that it is waiting for a channel switch announcement, the non-AP STA waits for further instructions from the AP and transitions to the new channel provided in the frame indicating a Channel Switch or Extended Channel Switch. However, if the Next Action field indicates that the next action is to seek an alternative connection, the non-AP STA may consider itself disassociated from the current BSS and seek an alternative BSS on another channel (in the 6 GHz band or another band). During this time, the non-AP STA does not transmit anything on the existing operating channel.

[0068] 14 shows a schematic, partially boxed diagram of a communication device 1400 according to embodiments. The communication device 1400 can be implemented as an AP or a STA according to embodiments.

[0069] As shown in Figure 14, the communication device 1400 may include circuitry 1414, at least one wireless transmitter 1402, at least one wireless receiver 1404, and at least one antenna 1412 (only one antenna is shown in Figure 14 for purposes of illustration for simplicity). The circuitry 1414 may include at least one controller 1406 that is used in carrying out the tasks it is designed to perform with the aid of software and hardware, including controlling communications with one or more other communication devices in a wireless network. The circuitry 1414 may further include at least one transmit signal generator 1408 and at least one receive signal processor 1410.The at least one controller 1406 can control at least one transmission signal generator 1408 to generate frames (e.g., a Probe Request frame if the communication device 1400 is an STA, and a Reduced Neighbor Report element, a Neighbor Report element, a FILS Discovery frame, a Beacon frame, a Probe Response frame, a Cease Transmission frame, and a Trigger frame) to be sent to one or more other transmission devices through the at least one wireless transmitter 1402, and further control at least one controller 1406 to generate frames (e.g., a Reduced Neighbor Report element, a Neighbor Report element, a FILS Discovery frame, a Beacon frame, a Probe Response frame, a Cease Transmission frame, and a Trigger frame) to be received from one or more other communication devices through the at least one wireless receiver 1404 under the control of the at least one controller 1406. The at least one transmit signal generator 1408 and the at least one receive signal processor 1410 may be standalone modules of the communication device 1400 that communicate with the at least one controller 1406 for the functions described above, as shown in FIG. 14. Alternatively, the at least one transmit signal generator 1408 and the at least one receive signal processor 1410 may be included in the at least one controller 1406.However, those skilled in the art will appreciate that the arrangement of these functional modules is flexible and may be changed according to actual needs and / or requirements. The data processing device, storage device, and other related control devices may be provided on an appropriate circuit board and / or chipset. In each embodiment, in operation, at least one wireless transmitter 1402, at least one wireless receiver 1404, and at least one antenna 1412 may be controlled by at least one controller 1406.

[0070] In operation, the communication device 1400 provides a function required for 6 GHz frequency coordination. For example, the communication device 1400 is a STA, and the wireless receiver 1404 in operation can receive information identifying an operating channel of an access point (AP) on a channel different from the operating channel, which further indicates whether a probe request frame is permitted to be transmitted before receiving an enable signal on the operating channel. In operation, the circuit 1414 determines from the information whether to generate a probe request frame to transmit before receiving an enable signal on the operating channel, in which case the circuit 1414 is further configured to scan the operating channel for an enable signal without transmitting a probe request frame based on a determination that a probe request frame is not permitted to be transmitted before receiving an enable signal on the operating channel. Alternatively, as a more general case, the information from the AP can indicate that a particular category of initial transmission from a client device (e.g., a GAS (general advertisement service) public action frame, a probe request frame) is permitted before receiving an enable signal. In operation, the circuit 1414 can determine from the information whether to generate a frame permitted to be transmitted to the AP or to perform a passive scan to receive an enable signal.

[0071] This information can be conveyed in a Reduced Neighbor Report element, a Neighbor Report element, or a Fast Initial Link Setup (FILS) Discovery frame. The enable signal can be a Beacon frame, a Probe Response frame, a Fast Initial Link Setup (FILS) Discovery frame, or a Trigger frame transmitted on the operating channel.

[0072] The communications device 1400 may further be configured to maintain an automatic frequency coordination (AFC) state machine for the operating channel, the AFC state machine transitioning to an Enabled state or remaining in an Enabled state upon receiving an enable signal.

[0073] Further, the communication device 1400 can be configured to start an enablement timer upon receiving an enable signal, where the enablement timer is set to an initial value equal to the value of AFC_ENABLEMENT_PERIOD, and the AFC state machine remains in the Enabled state for a period based on the enablement timer.

[0074] The wireless receiver 1404 may be further configured to receive a signal from the AP indicating a value of AFC_ENABLEMENT_PERIOD, where the value of AFC_ENABLEMENT_PERIOD is defined by the AP.

[0075] The wireless transmitter 1402 can be configured to transmit one or more frames on an operating channel when the AFC state machine is in the Enabled state.

[0076] The AFC state machine may transition to the Unenabled state when an enablement timer expires or when the receiver 1404 receives a stop transmission instruction from the AP, in which case the transmitter 1402 may be further configured not to transmit on the operating channel when the AFC state machine is in the Unenabled state.

[0077] For example, the communications device 1400 can be an AP configured to advertise its operating channel information on a channel different from the operating channel, and the circuitry 1414, in operation, can generate a signal including information indicating whether it is permitted to transmit a probe request frame before receiving an enable signal on the operating channel. The transmitter 1402, in operation, can transmit the generated signal on the channel to one or more communications devices.

[0078] The signal may include information indicative of the AFC parameters of another AP.

[0079] The information may include an Active Scan Allowed field indicating whether or not a probe request frame is permitted to be transmitted prior to receiving an enable signal on the operating channel based on a value of the Active Scan Allowed field, and the receiver 1404, in operation, receives a value of the Active Scan Allowed field for the operating channel from an automatic frequency coordination (AFC) system. The signal may further include information indicating a value of AFC_ENABLEMENT_PERIOD.

[0080] The communications device 1400 may be further configured to determine a value for the Active Scan Allowed field based on a maximum transmit power of the operating channel received from an automatic frequency tuning (AFC) system, such that transmission of a probe request frame is not permitted when the maximum transmit power is below a threshold.

[0081] Further, the circuitry can be further configured to generate a stop transmission instruction, and the transmitter 1402 can be further configured to send the stop transmission instruction to associated STAs of the AP to stop transmitting on the operating channel.

[0082] FIG. 15 shows a flow diagram 1500 illustrating a communication method according to embodiments. In step 1502, information identifying an operating channel of an access point (AP) can be received on a channel different from the operating channel, and the information further indicates whether a probe request frame is permitted to be transmitted before receiving an enable signal on the operating channel. In step 1504, a decision can be made based on the information whether to generate a probe request frame to transmit before receiving an enable signal on the operating channel. In step 1506, based on a determination that a probe request frame is not permitted to be transmitted before receiving an enable signal on the operating channel, a scan for an enable signal can be started on the operating channel without transmitting a probe request frame.

[0083] FIG. 16 illustrates a configuration of a communication device 1600, for example, a communication device, for example, a STA, according to each embodiment. Similar to the schematic example of a communication device illustrated in FIG. 14, the communication device 1600 in the schematic example of FIG. 16 includes at least one antenna 1602 having at least one wireless transmitter and at least one wireless receiver (for the sake of brevity, the wireless transmitter and wireless receiver are not illustrated in FIG. 16), and a circuit 1604. The circuit 1604 may include at least one controller or CPU 1606, which is used when performing the tasks that the CPU 1606 is designed to perform with the assistance of software and hardware, including controlling communications with another communication device, such as another STA or an AP.

[0084] The circuit 1604 may further include a location determination module 1608 responsible for determining the location of the communication device 1600, which may include latitude / longitude information of the geolocation position of the communication device. In some regulatory domains, the AFC system uses the location information to determine frequency channels available to the STA for wireless communication. The circuit 1604 may further include an AFC operation module 1610 responsible for maintaining various parameters related to the operation of AFC (such as AFC_ENABLEMENT_PERIOD and maximum transmit power limit). This module may also be responsible for tracking an AFC enablement timer to ensure that the STA receives an enable signal before the timer expires. The circuit 1704 may further include an AFC enablement state module 1612 that maintains an AFC enablement state when operating on a channel that requires AFC operation.

[0085] FIG. 17 illustrates a configuration of a communication device 1700 (e.g., an AP) according to each embodiment. Similar to the schematic example of a communication device illustrated in FIG. 14, the communication device 1700 in the schematic example of FIG. 17 includes at least one antenna 1702 having at least one wireless transmitter and at least one wireless receiver (the wireless transmitter and wireless receiver are not illustrated in FIG. 17 for the sake of brevity), and a circuit 1704. The circuit 1704 may include at least one controller or CPU 1706, which is used when performing the tasks that the CPU 1706 is designed to perform with the assistance of software and hardware, including controlling communications with another communication device, such as a STA or another AP.

[0086] The circuit 1704 may further include an AFC system interface module 1712, which maintains information necessary to communicate with the AFC system and acts as a gateway to the AFC system and AFC database. The actual communication with the AFC system may be through a wired interface. The circuit 1704 may further include a location determination module 1708, which is responsible for determining the location of the AP device, which may include latitude / longitude information of the AP's geolocation position and the AP's altitude above the ground. The location information may be used by the AFC system to determine the frequency channels that the AP and STAs associated with the AP may use. The circuit 1704 may further include an AFC operation module 1710, which is responsible for maintaining various parameters related to the operation of AFC (such as AFC_ENABLEMENT_PERIOD and maximum transmit power limit). This module may also be responsible for managing the channels being used by the STAs associated with the AP, which may include sending enable signals on the channels, sending AFC parameters, sending stop transmission instructions, etc.

[0087] As described above, the embodiments of the present disclosure provide an advanced communication system, communication method, and communication device that enable 6 GHz frequency coordination.

[0088] The present disclosure can be implemented by software, by hardware, or by software cooperating with hardware. Each functional block used in the description of each embodiment above can be implemented in part or in whole by an LSI such as an integrated circuit, and each process described in each embodiment can be controlled in part or in whole by the same LSI or a combination of LSIs. The LSI can be formed as a chip individually, or a single chip can be formed to include some or all of the functional blocks. The LSI can include a data input / output unit coupled to it. Depending on the degree of integration, the LSI can also be called an IC, a system LSI, a super LSI, or an ultra LSI. However, the technology for implementing an integrated circuit is not limited to an LSI, and can be implemented by using a dedicated circuit, a general-purpose processor, or a dedicated processor. Furthermore, an FPGA (field programmable gate array) that can be programmed after the LSI is manufactured, or a reconfigurable processor that can reconfigure the connections and settings of the circuit cells arranged inside the LSI can also be used. The present disclosure can be implemented as digital processing or analog processing. If, as a result of advances in semiconductor technology or other derivative technologies, LSI is replaced by a future integrated circuit technology, the future integrated circuit technology can be used to integrate the functional blocks. Biotechnology can also be applied.

[0089] The present disclosure may be implemented by any kind of apparatus, device or system having a communication capability (referred to as a communication apparatus).

[0090] A communication device may include a transceiver and processing / control circuitry. The transceiver may include a receiver and a transmitter and / or function as a receiver and a transmitter. The transceiver as a transmitter and a receiver may include an RF (radio frequency) module including an amplifier, an RF modulator / demodulator, etc., and one or more antennas.

[0091] Some non-limiting examples of such communications devices include phones (e.g., cell phones, smartphones), tablets, personal computers (PCs) (e.g., laptops, desktops, notebooks), cameras (e.g., digital still / video cameras), digital players (digital audio / video players), wearable devices (e.g., wearable cameras, smart watches, tracking devices), game consoles, e-book readers, telehealth / telemedicine equipment, vehicles that provide communications capabilities (e.g., cars, airplanes, ships), and various combinations thereof.

[0092] Communications devices are not limited to portable or portable, but can also include any type of equipment, device, or system that is non-portable or stationary, such as smart home devices (e.g., appliances, lights, smart meters, control panels), vending machines, and any other "things" in the Internet of Things (IoT) network.

[0093] Communications may include, for example, exchanging data through cellular systems, wireless LAN systems, satellite systems, etc., as well as various combinations thereof.

[0094] A communications device may include devices such as a controller or a sensor coupled to the communications device to perform the communications functions described in this disclosure. For example, a communications device may include a controller or a sensor that generates control or data signals used by the communications device to perform the communications functions of the communications device.

[0095] The communications apparatus may further include infrastructure facilities, such as base stations, access points, and any other apparatus, devices, or systems that communicate with or control apparatuses such as the apparatuses in the non-limiting examples above.

[0096] Although certain features of each embodiment are described with reference to a device, the corresponding features also apply to the method of each embodiment, and vice versa.

[0097] It will be appreciated by those skilled in the art that numerous changes and / or modifications may be made to the present disclosure as set forth in the specific embodiments without departing from the spirit or scope of the present disclosure as broadly described, and the embodiments herein are therefore to be considered in all respects as illustrative and not restrictive.

Claims

1. 1. A communication device, comprising: a receiver that, in operation, receives information identifying an operating channel of an access point (AP) in a 6 GHz band on a channel different from the operating channel of the 6 GHz band, the information further indicating whether a probe request frame is permitted to be transmitted before receiving an enable signal on the operating channel of the 6 GHz band; a circuit for determining, in operation, from said information whether to generate a probe request frame for transmission prior to receiving said enable signal on said 6 GHz operating channel; Equipped with the circuitry is further configured to scan for the enable signal in the 6 GHz operating channel without transmitting the probe request frame based on a determination that the probe request frame is not permitted to be transmitted prior to receiving the enable signal in the 6 GHz operating channel. Communications equipment.

2. The information is conveyed in a Reduced Neighbor Report element, a Neighbor Report element, or a Fast Initial Link Setup (FILS) Discovery frame. The communication device according to claim 1 .

3. The enable signal is a trigger frame transmitted on the 6 GHz operating channel. The communication device according to claim 1 .

4. the communication device is further configured to maintain an automatic frequency control (AFC) state machine for an operating channel in the 6 GHz band, and upon receiving the enable signal, the automatic frequency control (AFC) state machine transitions to an enabled state or remains in an enabled state. The communication device according to claim 1 .

5. the communication device is further configured to start an enablement timer upon receiving the enable signal, the enablement timer being set to an initial value equal to a value of AFC_ENABLEMENT_PERIOD, and the AFC state machine remaining in the Enable state for a period based on the enablement timer. The communication device according to claim 4.

6. the receiver is further configured to receive a signal from the AP indicating the value of the AFC_ENABLEMENT_PERIOD, the value of the AFC_ENABLEMENT_PERIOD being defined by the AP. The communication device according to claim 5.

7. a transmitter that, in operation, transmits one or more frames on an operating channel in the 6 GHz band when the AFC state machine is in the enabled state. The communication device according to claim 5.

8. The AFC state machine is further configured to transition to an Unenabled state when the enablement timer expires or when the receiver receives a stop transmission instruction from the AP, and the transmitter is further configured not to transmit on the operating channel in the 6 GHz band when the AFC state machine is in the Unenabled state. The communication device according to claim 7.

9. 1. A communication method comprising: receiving information identifying an operating channel of an access point (AP) in a 6 GHz band on a channel different from the operating channel of the 6 GHz band, the information further indicating whether a probe request frame is permitted to be transmitted before receiving an enable signal on the operating channel of the 6 GHz band; determining, based on the information, whether to generate a probe request frame to transmit before receiving the enable signal on the 6 GHz operating channel; based on a determination that transmission of the probe request frame is not permitted prior to receiving the enable signal in the 6 GHz operating channel, scanning the 6 GHz operating channel for the enable signal without transmitting the probe request frame; A communication method comprising:

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